CPU hardware ID (phys_id) is defined as u32 in structure acpi_processor, but phys_id is used as int in acpi processor driver, so it will lead to some inconsistence for the drivers.

Further more, when ARM64 was introduced into ACPI, CPU hardware ID used by ARM64 is 64 bits, u32 or int is not suitable.

So introduce typedef u32 phys_cpuid_t for x86 and ia64, and introduce a macro CPU_PHYS_ID_INVALID as (u32)(-1), use phys_cpuid_t when phys_id defined in acpi processor driver, and replace CPU_PHYS_ID_INVALID as -1 for phys_id, this will solve the inconsistence in acpi processor driver, and will prepare for the ACPI on ARM64 too.

phys_cpuid_t was suggested by Lorenzo and Catalin, and CPU_PHYS_ID_INVALID was suggested by Rafael.

CC: Rafael J Wysocki rjw@rjwysocki.net Signed-off-by: Hanjun Guo hanjun.guo@linaro.org --- arch/ia64/include/asm/acpi.h | 4 ++++ arch/ia64/kernel/acpi.c | 2 +- arch/x86/include/asm/acpi.h | 4 ++++ arch/x86/kernel/acpi/boot.c | 2 +- drivers/acpi/acpi_processor.c | 7 ++++--- drivers/acpi/processor_core.c | 30 +++++++++++++++--------------- include/acpi/processor.h | 6 +++--- include/linux/acpi.h | 2 +- 8 files changed, 33 insertions(+), 24 deletions(-)

diff --git a/arch/ia64/include/asm/acpi.h b/arch/ia64/include/asm/acpi.h index a1d91ab..ca1f0e4 100644 --- a/arch/ia64/include/asm/acpi.h +++ b/arch/ia64/include/asm/acpi.h @@ -34,6 +34,10 @@ #include <linux/numa.h> #include <asm/numa.h>

+typedef u32 phys_cpuid_t; + +#define CPU_PHYS_ID_INVALID (u32)(-1) + #ifdef CONFIG_ACPI extern int acpi_lapic; #define acpi_disabled 0 /* ACPI always enabled on IA64 */ diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c index e795cb8..368abeb 100644 --- a/arch/ia64/kernel/acpi.c +++ b/arch/ia64/kernel/acpi.c @@ -893,7 +893,7 @@ static int _acpi_map_lsapic(acpi_handle handle, int physid, int *pcpu) }

/* wrapper to silence section mismatch warning */ -int __ref acpi_map_cpu(acpi_handle handle, int physid, int *pcpu) +int __ref acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, int *pcpu) { return _acpi_map_lsapic(handle, physid, pcpu); } diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h index 3a45668..cd788dd 100644 --- a/arch/x86/include/asm/acpi.h +++ b/arch/x86/include/asm/acpi.h @@ -32,6 +32,10 @@ #include <asm/mpspec.h> #include <asm/realmode.h>

+typedef u32 phys_cpuid_t; + +#define CPU_PHYS_ID_INVALID (u32)(-1) + #ifdef CONFIG_ACPI extern int acpi_lapic; extern int acpi_ioapic; diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index b9e30da..3f78219 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -750,7 +750,7 @@ static int _acpi_map_lsapic(acpi_handle handle, int physid, int *pcpu) }

/* wrapper to silence section mismatch warning */ -int __ref acpi_map_cpu(acpi_handle handle, int physid, int *pcpu) +int __ref acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, int *pcpu) { return _acpi_map_lsapic(handle, physid, pcpu); } diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c index 1020b1b..e6c7c56 100644 --- a/drivers/acpi/acpi_processor.c +++ b/drivers/acpi/acpi_processor.c @@ -170,7 +170,7 @@ static int acpi_processor_hotadd_init(struct acpi_processor *pr) acpi_status status; int ret;

- if (pr->phys_id == -1) + if (pr->phys_id == CPU_PHYS_ID_INVALID) return -ENODEV;

status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta); @@ -215,7 +215,8 @@ static int acpi_processor_get_info(struct acpi_device *device) union acpi_object object = { 0 }; struct acpi_buffer buffer = { sizeof(union acpi_object), &object }; struct acpi_processor *pr = acpi_driver_data(device); - int phys_id, cpu_index, device_declaration = 0; + phys_cpuid_t phys_id; + int cpu_index, device_declaration = 0; acpi_status status = AE_OK; static int cpu0_initialized; unsigned long long value; @@ -263,7 +264,7 @@ static int acpi_processor_get_info(struct acpi_device *device) }

phys_id = acpi_get_phys_id(pr->handle, device_declaration, pr->acpi_id); - if (phys_id < 0) + if (phys_id == CPU_PHYS_ID_INVALID) acpi_handle_debug(pr->handle, "failed to get CPU physical ID.\n"); pr->phys_id = phys_id;

diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c index 02e4839..f3b10a9 100644 --- a/drivers/acpi/processor_core.c +++ b/drivers/acpi/processor_core.c @@ -13,7 +13,7 @@ ACPI_MODULE_NAME("processor_core");

static int map_lapic_id(struct acpi_subtable_header *entry, - u32 acpi_id, int *apic_id) + u32 acpi_id, phys_cpuid_t *apic_id) { struct acpi_madt_local_apic *lapic = container_of(entry, struct acpi_madt_local_apic, header); @@ -29,7 +29,7 @@ static int map_lapic_id(struct acpi_subtable_header *entry, }

static int map_x2apic_id(struct acpi_subtable_header *entry, - int device_declaration, u32 acpi_id, int *apic_id) + int device_declaration, u32 acpi_id, phys_cpuid_t *apic_id) { struct acpi_madt_local_x2apic *apic = container_of(entry, struct acpi_madt_local_x2apic, header); @@ -46,7 +46,7 @@ static int map_x2apic_id(struct acpi_subtable_header *entry, }

static int map_lsapic_id(struct acpi_subtable_header *entry, - int device_declaration, u32 acpi_id, int *apic_id) + int device_declaration, u32 acpi_id, phys_cpuid_t *apic_id) { struct acpi_madt_local_sapic *lsapic = container_of(entry, struct acpi_madt_local_sapic, header); @@ -64,12 +64,12 @@ static int map_lsapic_id(struct acpi_subtable_header *entry, return 0; }

-static int map_madt_entry(int type, u32 acpi_id) +static phys_cpuid_t map_madt_entry(int type, u32 acpi_id) { unsigned long madt_end, entry; static struct acpi_table_madt *madt; static int read_madt; - int phys_id = -1; /* CPU hardware ID */ + phys_cpuid_t phys_id = CPU_PHYS_ID_INVALID; /* CPU hardware ID */

if (!read_madt) { if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_MADT, 0, @@ -105,12 +105,12 @@ static int map_madt_entry(int type, u32 acpi_id) return phys_id; }

-static int map_mat_entry(acpi_handle handle, int type, u32 acpi_id) +static phys_cpuid_t map_mat_entry(acpi_handle handle, int type, u32 acpi_id) { struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; union acpi_object *obj; struct acpi_subtable_header *header; - int phys_id = -1; + phys_cpuid_t phys_id = CPU_PHYS_ID_INVALID;

if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer))) goto exit; @@ -137,27 +137,27 @@ exit: return phys_id; }

-int acpi_get_phys_id(acpi_handle handle, int type, u32 acpi_id) +phys_cpuid_t acpi_get_phys_id(acpi_handle handle, int type, u32 acpi_id) { - int phys_id; + phys_cpuid_t phys_id;

phys_id = map_mat_entry(handle, type, acpi_id); - if (phys_id == -1) + if (phys_id == CPU_PHYS_ID_INVALID) phys_id = map_madt_entry(type, acpi_id);

return phys_id; }

-int acpi_map_cpuid(int phys_id, u32 acpi_id) +int acpi_map_cpuid(phys_cpuid_t phys_id, u32 acpi_id) { #ifdef CONFIG_SMP int i; #endif

- if (phys_id == -1) { + if (phys_id == CPU_PHYS_ID_INVALID) { /* * On UP processor, there is no _MAT or MADT table. - * So above phys_id is always set to -1. + * So above phys_id is always set to CPU_PHYS_ID_INVALID. * * BIOS may define multiple CPU handles even for UP processor. * For example, @@ -178,7 +178,7 @@ int acpi_map_cpuid(int phys_id, u32 acpi_id) if (nr_cpu_ids <= 1 && acpi_id == 0) return acpi_id; else - return phys_id; + return -1; }

#ifdef CONFIG_SMP @@ -196,7 +196,7 @@ int acpi_map_cpuid(int phys_id, u32 acpi_id)

int acpi_get_cpuid(acpi_handle handle, int type, u32 acpi_id) { - int phys_id; + phys_cpuid_t phys_id;

phys_id = acpi_get_phys_id(handle, type, acpi_id);

diff --git a/include/acpi/processor.h b/include/acpi/processor.h index b95dc32..4188a4d 100644 --- a/include/acpi/processor.h +++ b/include/acpi/processor.h @@ -196,7 +196,7 @@ struct acpi_processor_flags { struct acpi_processor { acpi_handle handle; u32 acpi_id; - u32 phys_id; /* CPU hardware ID such as APIC ID for x86 */ + phys_cpuid_t phys_id; /* CPU hardware ID such as APIC ID for x86 */ u32 id; /* CPU logical ID allocated by OS */ u32 pblk; int performance_platform_limit; @@ -310,8 +310,8 @@ static inline int acpi_processor_get_bios_limit(int cpu, unsigned int *limit) #endif /* CONFIG_CPU_FREQ */

/* in processor_core.c */ -int acpi_get_phys_id(acpi_handle, int type, u32 acpi_id); -int acpi_map_cpuid(int phys_id, u32 acpi_id); +phys_cpuid_t acpi_get_phys_id(acpi_handle, int type, u32 acpi_id); +int acpi_map_cpuid(phys_cpuid_t phys_id, u32 acpi_id); int acpi_get_cpuid(acpi_handle, int type, u32 acpi_id);

/* in processor_pdc.c */ diff --git a/include/linux/acpi.h b/include/linux/acpi.h index d459cd1..d5e91e7 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -147,7 +147,7 @@ void acpi_numa_arch_fixup(void);

#ifdef CONFIG_ACPI_HOTPLUG_CPU /* Arch dependent functions for cpu hotplug support */ -int acpi_map_cpu(acpi_handle handle, int physid, int *pcpu); +int acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, int *pcpu); int acpi_unmap_cpu(int cpu); #endif /* CONFIG_ACPI_HOTPLUG_CPU */

From: Graeme Gregory graeme.gregory@linaro.org

Now with the base changes to the arm memory mapping it is safe to convert to using ioremap to map in the tables after acpi_gbl_permanent_mmap is set.

CC: Rafael J Wysocki rjw@rjwysocki.net Tested-by: Robert Richter rrichter@cavium.com Acked-by: Robert Richter rrichter@cavium.com Signed-off-by: Al Stone al.stone@linaro.org Signed-off-by: Graeme Gregory graeme.gregory@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org --- drivers/acpi/osl.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c index f9eeae8..39748bb 100644 --- a/drivers/acpi/osl.c +++ b/drivers/acpi/osl.c @@ -336,11 +336,11 @@ acpi_map_lookup_virt(void __iomem *virt, acpi_size size) return NULL; }

-#ifndef CONFIG_IA64 -#define should_use_kmap(pfn) page_is_ram(pfn) -#else +#if defined(CONFIG_IA64) || defined(CONFIG_ARM64) /* ioremap will take care of cache attributes */ #define should_use_kmap(pfn) 0 +#else +#define should_use_kmap(pfn) page_is_ram(pfn) #endif

static void __iomem *acpi_map(acpi_physical_address pg_off, unsigned long pg_sz)

From: Al Stone al.stone@linaro.org

As we want to get ACPI tables to parse and then use the information for system initialization, we should get the RSDP (Root System Description Pointer) first, it then locates Extended Root Description Table (XSDT) which contains all the 64-bit physical address that pointer to other boot-time tables.

Introduce acpi.c and its related head file in this patch to provide fundamental needs of extern variables and functions for ACPI core, and then get boot-time tables as needed. - asm/acenv.h for arch specific ACPICA environments and implementation, It is needed unconditionally by ACPI core; - asm/acpi.h for arch specific variables and functions needed by ACPI driver core; - acpi.c for ARM64 related ACPI implementation for ACPI driver core;

acpi_boot_table_init() is introduced to get RSDP and boot-time tables, it will be called in setup_arch() before paging_init(), so we should use eary_memremap() mechanism here to get the RSDP and all the table pointers.

FADT Major.Minor version was introduced in ACPI 5.1, it is the same as ACPI version.

In ACPI 5.1, some major gaps are fixed for ARM, such as updates in MADT table for GIC and SMP init, without those updates, we can not get the MPIDR for SMP init, and GICv2/3 related init information, so we can't boot arm64 ACPI properly with table versions predating 5.1.

If firmware provides ACPI tables with ACPI version less than 5.1, OS has no way to retrieve the configuration data that is necessary to init SMP boot protocol and the GIC properly, so disable ACPI if we get an FADT table with version less that 5.1 when acpi_boot_table_init() called.

CC: Catalin Marinas catalin.marinas@arm.com CC: Will Deacon will.deacon@arm.com CC: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Tested-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com Tested-by: Yijing Wang wangyijing@huawei.com Tested-by: Mark Langsdorf mlangsdo@redhat.com Tested-by: Jon Masters jcm@redhat.com Tested-by: Timur Tabi timur@codeaurora.org Tested-by: Robert Richter rrichter@cavium.com Acked-by: Robert Richter rrichter@cavium.com Signed-off-by: Al Stone al.stone@linaro.org Signed-off-by: Graeme Gregory graeme.gregory@linaro.org Signed-off-by: Tomasz Nowicki tomasz.nowicki@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org --- arch/arm64/include/asm/acenv.h | 18 ++++++++ arch/arm64/include/asm/acpi.h | 45 ++++++++++++++++++ arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/acpi.c | 101 +++++++++++++++++++++++++++++++++++++++++ arch/arm64/kernel/setup.c | 5 ++ 5 files changed, 170 insertions(+) create mode 100644 arch/arm64/include/asm/acenv.h create mode 100644 arch/arm64/include/asm/acpi.h create mode 100644 arch/arm64/kernel/acpi.c

diff --git a/arch/arm64/include/asm/acenv.h b/arch/arm64/include/asm/acenv.h new file mode 100644 index 0000000..b49166f --- /dev/null +++ b/arch/arm64/include/asm/acenv.h @@ -0,0 +1,18 @@ +/* + * ARM64 specific ACPICA environments and implementation + * + * Copyright (C) 2014, Linaro Ltd. + * Author: Hanjun Guo hanjun.guo@linaro.org + * Author: Graeme Gregory graeme.gregory@linaro.org + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef _ASM_ACENV_H +#define _ASM_ACENV_H + +/* It is required unconditionally by ACPI core, update it when needed. */ + +#endif /* _ASM_ACENV_H */ diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h new file mode 100644 index 0000000..8b837ab --- /dev/null +++ b/arch/arm64/include/asm/acpi.h @@ -0,0 +1,45 @@ +/* + * Copyright (C) 2013-2014, Linaro Ltd. + * Author: Al Stone al.stone@linaro.org + * Author: Graeme Gregory graeme.gregory@linaro.org + * Author: Hanjun Guo hanjun.guo@linaro.org + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation; + */ + +#ifndef _ASM_ACPI_H +#define _ASM_ACPI_H + +/* Basic configuration for ACPI */ +#ifdef CONFIG_ACPI +#define acpi_strict 1 /* No out-of-spec workarounds on ARM64 */ +extern int acpi_disabled; +extern int acpi_noirq; +extern int acpi_pci_disabled; + +static inline void disable_acpi(void) +{ + acpi_disabled = 1; + acpi_pci_disabled = 1; + acpi_noirq = 1; +} + +/* + * It's used from ACPI core in kdump to boot UP system with SMP kernel, + * with this check the ACPI core will not override the CPU index + * obtained from GICC with 0 and not print some error message as well. + * Since MADT must provide at least one GICC structure for GIC + * initialization, CPU will be always available in MADT on ARM64. + */ +static inline bool acpi_has_cpu_in_madt(void) +{ + return true; +} + +static inline void arch_fix_phys_package_id(int num, u32 slot) { } + +#endif /* CONFIG_ACPI */ + +#endif /*_ASM_ACPI_H*/ diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index eaa77ed..8bdc6bd 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -34,6 +34,7 @@ arm64-obj-$(CONFIG_KGDB) += kgdb.o arm64-obj-$(CONFIG_EFI) += efi.o efi-stub.o efi-entry.o arm64-obj-$(CONFIG_PCI) += pci.o arm64-obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o +arm64-obj-$(CONFIG_ACPI) += acpi.o

obj-y += $(arm64-obj-y) vdso/ obj-m += $(arm64-obj-m) diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c new file mode 100644 index 0000000..f052e7a --- /dev/null +++ b/arch/arm64/kernel/acpi.c @@ -0,0 +1,101 @@ +/* + * ARM64 Specific Low-Level ACPI Boot Support + * + * Copyright (C) 2013-2014, Linaro Ltd. + * Author: Al Stone al.stone@linaro.org + * Author: Graeme Gregory graeme.gregory@linaro.org + * Author: Hanjun Guo hanjun.guo@linaro.org + * Author: Tomasz Nowicki tomasz.nowicki@linaro.org + * Author: Naresh Bhat naresh.bhat@linaro.org + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#define pr_fmt(fmt) "ACPI: " fmt + +#include <linux/acpi.h> +#include <linux/bootmem.h> +#include <linux/cpumask.h> +#include <linux/init.h> +#include <linux/irq.h> +#include <linux/irqdomain.h> +#include <linux/memblock.h> +#include <linux/smp.h> + +int acpi_noirq; /* skip ACPI IRQ initialization */ +int acpi_disabled; +EXPORT_SYMBOL(acpi_disabled); + +int acpi_pci_disabled; /* skip ACPI PCI scan and IRQ initialization */ +EXPORT_SYMBOL(acpi_pci_disabled); + +/* + * __acpi_map_table() will be called before page_init(), so early_ioremap() + * or early_memremap() should be called here to for ACPI table mapping. + */ +char *__init __acpi_map_table(unsigned long phys, unsigned long size) +{ + if (!phys || !size) + return NULL; + + return early_memremap(phys, size); +} + +void __init __acpi_unmap_table(char *map, unsigned long size) +{ + if (!map || !size) + return; + + early_memunmap(map, size); +} + +static int __init acpi_parse_fadt(struct acpi_table_header *table) +{ + struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table; + + /* + * Revision in table header is the FADT Major revision, and there + * is a minor revision of FADT which was introduced by ACPI 5.1, + * we only deal with ACPI 5.1 or newer revision to get GIC and SMP + * boot protocol configuration data, or we will disable ACPI. + */ + if (table->revision > 5 || + (table->revision == 5 && fadt->minor_revision >= 1)) + return 0; + + pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will disable ACPI\n", + table->revision, fadt->minor_revision); + disable_acpi(); + + return -EINVAL; +} + +/* + * acpi_boot_table_init() called from setup_arch(), always. + * 1. find RSDP and get its address, and then find XSDT + * 2. extract all tables and checksums them all + * 3. check ACPI FADT revision + * + * We can parse ACPI boot-time tables such as MADT after + * this function is called. + */ +void __init acpi_boot_table_init(void) +{ + /* If acpi_disabled, bail out */ + if (acpi_disabled) + return; + + /* Initialize the ACPI boot-time table parser. */ + if (acpi_table_init()) { + disable_acpi(); + return; + } + + if (acpi_table_parse(ACPI_SIG_FADT, acpi_parse_fadt)) { + /* disable ACPI if no FADT is found */ + disable_acpi(); + pr_err("Can't find FADT\n"); + } +} diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 20fe293..ecd1a77 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -17,6 +17,7 @@ * along with this program. If not, see http://www.gnu.org/licenses/. */

+#include <linux/acpi.h> #include <linux/export.h> #include <linux/kernel.h> #include <linux/stddef.h> @@ -45,6 +46,7 @@ #include <linux/efi.h> #include <linux/personality.h>

+#include <asm/acpi.h> #include <asm/fixmap.h> #include <asm/cpu.h> #include <asm/cputype.h> @@ -398,6 +400,9 @@ void __init setup_arch(char **cmdline_p) efi_init(); arm64_memblock_init();

+ /* Parse the ACPI tables for possible boot-time configuration */ + acpi_boot_table_init(); + paging_init(); request_standard_resources();

From: Graeme Gregory graeme.gregory@linaro.org

ACPI 5.1 does not currently support S states for ARM64 hardware but ACPI code will call acpi_target_system_state() for device power managment, so introduce sleep_arm.c to allow other drivers to function until S states are defined.

Since it is arm64 specific stub holder, so let sleep_arm.c to ARM64 specific.

CC: Rafael J. Wysocki rjw@rjwysocki.net Tested-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com Tested-by: Yijing Wang wangyijing@huawei.com Tested-by: Mark Langsdorf mlangsdo@redhat.com Tested-by: Jon Masters jcm@redhat.com Tested-by: Timur Tabi timur@codeaurora.org Tested-by: Robert Richter rrichter@cavium.com Acked-by: Robert Richter rrichter@cavium.com Signed-off-by: Graeme Gregory graeme.gregory@linaro.org Signed-off-by: Tomasz Nowicki tomasz.nowicki@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org --- arch/arm64/kernel/Makefile | 2 +- arch/arm64/kernel/acpi_sleep.c | 28 ++++++++++++++++++++++++++++ drivers/acpi/Makefile | 2 ++ 3 files changed, 31 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/kernel/acpi_sleep.c

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 8bdc6bd..f2c488b 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -34,7 +34,7 @@ arm64-obj-$(CONFIG_KGDB) += kgdb.o arm64-obj-$(CONFIG_EFI) += efi.o efi-stub.o efi-entry.o arm64-obj-$(CONFIG_PCI) += pci.o arm64-obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o -arm64-obj-$(CONFIG_ACPI) += acpi.o +arm64-obj-$(CONFIG_ACPI) += acpi.o acpi_sleep.o

obj-y += $(arm64-obj-y) vdso/ obj-m += $(arm64-obj-m) diff --git a/arch/arm64/kernel/acpi_sleep.c b/arch/arm64/kernel/acpi_sleep.c new file mode 100644 index 0000000..54578ef --- /dev/null +++ b/arch/arm64/kernel/acpi_sleep.c @@ -0,0 +1,28 @@ +/* + * ARM64 Specific Sleep Functionality + * + * Copyright (C) 2013-2014, Linaro Ltd. + * Author: Graeme Gregory graeme.gregory@linaro.org + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/acpi.h> + +/* + * Currently the ACPI 5.1 standard does not define S states in a + * manner which is usable for ARM64. These two stubs are sufficient + * that system initialises and device PM works. + */ +u32 acpi_target_system_state(void) +{ + return ACPI_STATE_S0; +} +EXPORT_SYMBOL_GPL(acpi_target_system_state); + +int __init acpi_sleep_init(void) +{ + return -ENOSYS; +} diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile index f74317c..753785d 100644 --- a/drivers/acpi/Makefile +++ b/drivers/acpi/Makefile @@ -23,7 +23,9 @@ acpi-y += nvs.o

# Power management related files acpi-y += wakeup.o +ifneq (,$(findstring $(ARCH),x86 ia64)) acpi-y += sleep.o +endif acpi-y += device_pm.o acpi-$(CONFIG_ACPI_SLEEP) += proc.o

From: Al Stone al.stone@linaro.org

This implements the following policy to decide whether ACPI should be used to boot the system: - acpi=off: ACPI will not be used to boot the system, even if there is no alternative available (e.g., device tree is empty) - acpi=force: only ACPI will be used to boot the system; if that fails, there will be no fallback to alternative methods (such as device tree) - otherwise, ACPI will be used as a fallback if the device tree turns out to lack a platform description; the heuristic to decide this is whether /chosen is the only node present at depth 1

CC: Catalin Marinas catalin.marinas@arm.com CC: Will Deacon will.deacon@arm.com CC: Rafael J. Wysocki rjw@rjwysocki.net Signed-off-by: Al Stone al.stone@linaro.org Signed-off-by: Graeme Gregory graeme.gregory@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org --- Documentation/kernel-parameters.txt | 3 ++- arch/arm64/include/asm/acpi.h | 7 +++++ arch/arm64/kernel/acpi.c | 52 +++++++++++++++++++++++++++++++++---- 3 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 176d4fe..d6a952e 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -165,7 +165,7 @@ multipliers 'Kilo', 'Mega', and 'Giga', equalling 2^10, 2^20, and 2^30 bytes respectively. Such letter suffixes can also be entirely omitted.

- acpi= [HW,ACPI,X86] + acpi= [HW,ACPI,X86,ARM64] Advanced Configuration and Power Interface Format: { force | off | strict | noirq | rsdt } force -- enable ACPI if default was off @@ -175,6 +175,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. strictly ACPI specification compliant. rsdt -- prefer RSDT over (default) XSDT copy_dsdt -- copy DSDT to memory + For ARM64, ONLY "acpi=off" or "acpi=force" are available

See also Documentation/power/runtime_pm.txt, pci=noacpi

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h index 95c95d7..111c8fa 100644 --- a/arch/arm64/include/asm/acpi.h +++ b/arch/arm64/include/asm/acpi.h @@ -39,6 +39,13 @@ static inline void disable_acpi(void) acpi_noirq = 1; }

+static inline void enable_acpi(void) +{ + acpi_disabled = 0; + acpi_pci_disabled = 0; + acpi_noirq = 0; +} + /* * It's used from ACPI core in kdump to boot UP system with SMP kernel, * with this check the ACPI core will not override the CPU index diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index f052e7a..bdcc9fc 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -22,15 +22,49 @@ #include <linux/irq.h> #include <linux/irqdomain.h> #include <linux/memblock.h> +#include <linux/of_fdt.h> #include <linux/smp.h>

-int acpi_noirq; /* skip ACPI IRQ initialization */ -int acpi_disabled; +int acpi_noirq = 1; /* skip ACPI IRQ initialization */ +int acpi_disabled = 1; EXPORT_SYMBOL(acpi_disabled);

-int acpi_pci_disabled; /* skip ACPI PCI scan and IRQ initialization */ +int acpi_pci_disabled = 1; /* skip ACPI PCI scan and IRQ initialization */ EXPORT_SYMBOL(acpi_pci_disabled);

+static bool __initdata param_acpi_off; +static bool __initdata param_acpi_force; + +static int __init parse_acpi(char *arg) +{ + if (!arg) + return -EINVAL; + + /* "acpi=off" disables both ACPI table parsing and interpreter */ + if (strcmp(arg, "off") == 0) + param_acpi_off = true; + else if (strcmp(arg, "force") == 0) /* force ACPI to be enabled */ + param_acpi_force = true; + else + return -EINVAL; /* Core will print when we return error */ + + return 0; +} +early_param("acpi", parse_acpi); + +static int __init dt_scan_depth1_nodes(unsigned long node, + const char *uname, int depth, + void *data) +{ + /* + * Return 1 as soon as we encounter a node at depth 1 that is + * not the /chosen node. + */ + if (depth == 1 && (strcmp(uname, "chosen") != 0)) + return 1; + return 0; +} + /* * __acpi_map_table() will be called before page_init(), so early_ioremap() * or early_memremap() should be called here to for ACPI table mapping. @@ -83,10 +117,18 @@ static int __init acpi_parse_fadt(struct acpi_table_header *table) */ void __init acpi_boot_table_init(void) { - /* If acpi_disabled, bail out */ - if (acpi_disabled) + /* + * Enable ACPI instead of device tree unless + * - ACPI has been disabled explicitly (acpi=off), or + * - the device tree is not empty (it has more than just a /chosen node) + * and ACPI has not been force enabled (acpi=force) + */ + if (param_acpi_off || + (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL))) return;

+ enable_acpi(); + /* Initialize the ACPI boot-time table parser. */ if (acpi_table_init()) { disable_acpi();

From: Graeme Gregory graeme.gregory@linaro.org

There are two flags: PSCI_COMPLIANT and PSCI_USE_HVC. When set, the former signals to the OS that the firmware is PSCI compliant. The latter selects the appropriate conduit for PSCI calls by toggling between Hypervisor Calls (HVC) and Secure Monitor Calls (SMC).

FADT table contains such information in ACPI 5.1, FADT table was parsed in ACPI table init and copy to struct acpi_gbl_FADT, so use the flags in struct acpi_gbl_FADT for PSCI init.

Since ACPI 5.1 doesn't support self defined PSCI function IDs, which means that only PSCI 0.2+ is supported in ACPI.

CC: Lorenzo Pieralisi lorenzo.pieralisi@arm.com CC: Catalin Marinas catalin.marinas@arm.com CC: Will Deacon will.deacon@arm.com Tested-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com Tested-by: Yijing Wang wangyijing@huawei.com Tested-by: Mark Langsdorf mlangsdo@redhat.com Tested-by: Jon Masters jcm@redhat.com Tested-by: Timur Tabi timur@codeaurora.org Tested-by: Robert Richter rrichter@cavium.com Acked-by: Robert Richter rrichter@cavium.com Signed-off-by: Graeme Gregory graeme.gregory@linaro.org Signed-off-by: Tomasz Nowicki tomasz.nowicki@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org --- arch/arm64/include/asm/acpi.h | 15 +++++++++ arch/arm64/include/asm/psci.h | 3 +- arch/arm64/kernel/psci.c | 78 ++++++++++++++++++++++++++++++------------- arch/arm64/kernel/setup.c | 8 +++-- 4 files changed, 76 insertions(+), 28 deletions(-)

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h index 111c8fa..b813019 100644 --- a/arch/arm64/include/asm/acpi.h +++ b/arch/arm64/include/asm/acpi.h @@ -32,6 +32,18 @@ extern int acpi_disabled; extern int acpi_noirq; extern int acpi_pci_disabled;

+/* 1 to indicate PSCI 0.2+ is implemented */ +static inline bool acpi_psci_present(void) +{ + return acpi_gbl_FADT.arm_boot_flags & ACPI_FADT_PSCI_COMPLIANT; +} + +/* 1 to indicate HVC must be used instead of SMC as the PSCI conduit */ +static inline bool acpi_psci_use_hvc(void) +{ + return acpi_gbl_FADT.arm_boot_flags & ACPI_FADT_PSCI_USE_HVC; +} + static inline void disable_acpi(void) { acpi_disabled = 1; @@ -60,6 +72,9 @@ static inline bool acpi_has_cpu_in_madt(void)

static inline void arch_fix_phys_package_id(int num, u32 slot) { }

+#else +static inline bool acpi_psci_present(void) { return false; } +static inline bool acpi_psci_use_hvc(void) { return false; } #endif /* CONFIG_ACPI */

#endif /*_ASM_ACPI_H*/ diff --git a/arch/arm64/include/asm/psci.h b/arch/arm64/include/asm/psci.h index e5312ea..2454bc5 100644 --- a/arch/arm64/include/asm/psci.h +++ b/arch/arm64/include/asm/psci.h @@ -14,6 +14,7 @@ #ifndef __ASM_PSCI_H #define __ASM_PSCI_H

-int psci_init(void); +int psci_dt_init(void); +int psci_acpi_init(void);

#endif /* __ASM_PSCI_H */ diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c index f1dbca7..0ec0dc5 100644 --- a/arch/arm64/kernel/psci.c +++ b/arch/arm64/kernel/psci.c @@ -15,6 +15,7 @@

#define pr_fmt(fmt) "psci: " fmt

+#include <linux/acpi.h> #include <linux/init.h> #include <linux/of.h> #include <linux/smp.h> @@ -24,6 +25,7 @@ #include <linux/slab.h> #include <uapi/linux/psci.h>

+#include <asm/acpi.h> #include <asm/compiler.h> #include <asm/cpu_ops.h> #include <asm/errno.h> @@ -304,6 +306,33 @@ static void psci_sys_poweroff(void) invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0); }

+static void __init psci_0_2_set_functions(void) +{ + pr_info("Using standard PSCI v0.2 function IDs\n"); + psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_0_2_FN64_CPU_SUSPEND; + psci_ops.cpu_suspend = psci_cpu_suspend; + + psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF; + psci_ops.cpu_off = psci_cpu_off; + + psci_function_id[PSCI_FN_CPU_ON] = PSCI_0_2_FN64_CPU_ON; + psci_ops.cpu_on = psci_cpu_on; + + psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN64_MIGRATE; + psci_ops.migrate = psci_migrate; + + psci_function_id[PSCI_FN_AFFINITY_INFO] = PSCI_0_2_FN64_AFFINITY_INFO; + psci_ops.affinity_info = psci_affinity_info; + + psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE] = + PSCI_0_2_FN_MIGRATE_INFO_TYPE; + psci_ops.migrate_info_type = psci_migrate_info_type; + + arm_pm_restart = psci_sys_reset; + + pm_power_off = psci_sys_poweroff; +} + /* * PSCI Function IDs for v0.2+ are well defined so use * standard values. @@ -337,29 +366,7 @@ static int __init psci_0_2_init(struct device_node *np) } }

- pr_info("Using standard PSCI v0.2 function IDs\n"); - psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_0_2_FN64_CPU_SUSPEND; - psci_ops.cpu_suspend = psci_cpu_suspend; - - psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF; - psci_ops.cpu_off = psci_cpu_off; - - psci_function_id[PSCI_FN_CPU_ON] = PSCI_0_2_FN64_CPU_ON; - psci_ops.cpu_on = psci_cpu_on; - - psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN64_MIGRATE; - psci_ops.migrate = psci_migrate; - - psci_function_id[PSCI_FN_AFFINITY_INFO] = PSCI_0_2_FN64_AFFINITY_INFO; - psci_ops.affinity_info = psci_affinity_info; - - psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE] = - PSCI_0_2_FN_MIGRATE_INFO_TYPE; - psci_ops.migrate_info_type = psci_migrate_info_type; - - arm_pm_restart = psci_sys_reset; - - pm_power_off = psci_sys_poweroff; + psci_0_2_set_functions();

out_put_node: of_node_put(np); @@ -412,7 +419,7 @@ static const struct of_device_id psci_of_match[] __initconst = { {}, };

-int __init psci_init(void) +int __init psci_dt_init(void) { struct device_node *np; const struct of_device_id *matched_np; @@ -427,6 +434,29 @@ int __init psci_init(void) return init_fn(np); }

+/* + * We use PSCI 0.2+ when ACPI is deployed on ARM64 and it's + * explicitly clarified in SBBR + */ +int __init psci_acpi_init(void) +{ + if (!acpi_psci_present()) { + pr_info("is not implemented in ACPI.\n"); + return -EOPNOTSUPP; + } + + pr_info("probing for conduit method from ACPI.\n"); + + if (acpi_psci_use_hvc()) + invoke_psci_fn = __invoke_psci_fn_hvc; + else + invoke_psci_fn = __invoke_psci_fn_smc; + + psci_0_2_set_functions(); + + return 0; +} + #ifdef CONFIG_SMP

static int __init cpu_psci_cpu_init(struct device_node *dn, unsigned int cpu) diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index cf29cd8..c83e909 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -409,10 +409,12 @@ void __init setup_arch(char **cmdline_p) efi_idmap_init(); early_ioremap_reset();

- if (acpi_disabled) + if (acpi_disabled) { unflatten_device_tree(); - - psci_init(); + psci_dt_init(); + } else { + psci_acpi_init(); + }

cpu_read_bootcpu_ops(); #ifdef CONFIG_SMP

MADT contains the information for MPIDR which is essential for SMP initialization, parse the GIC cpu interface structures to get the MPIDR value and map it to cpu_logical_map(), and add enabled cpu with valid MPIDR into cpu_possible_map.

ACPI 5.1 only has two explicit methods to boot up SMP, PSCI and Parking protocol, but the Parking protocol is only specified for ARMv7 now, so make PSCI as the only way for the SMP boot protocol before some updates for the ACPI spec or the Parking protocol spec.

Parking protocol patches for SMP boot will be sent to upstream when the new version of Parking protocol is ready.

CC: Lorenzo Pieralisi lorenzo.pieralisi@arm.com CC: Catalin Marinas catalin.marinas@arm.com CC: Will Deacon will.deacon@arm.com CC: Mark Rutland mark.rutland@arm.com Tested-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com Tested-by: Yijing Wang wangyijing@huawei.com Tested-by: Mark Langsdorf mlangsdo@redhat.com Tested-by: Jon Masters jcm@redhat.com Tested-by: Timur Tabi timur@codeaurora.org Tested-by: Robert Richter rrichter@cavium.com Acked-by: Robert Richter rrichter@cavium.com Signed-off-by: Hanjun Guo hanjun.guo@linaro.org Signed-off-by: Tomasz Nowicki tomasz.nowicki@linaro.org --- arch/arm64/include/asm/acpi.h | 2 + arch/arm64/include/asm/cpu_ops.h | 1 + arch/arm64/include/asm/smp.h | 5 +- arch/arm64/kernel/acpi.c | 149 ++++++++++++++++++++++++++++++++++++++- arch/arm64/kernel/cpu_ops.c | 2 +- arch/arm64/kernel/setup.c | 7 +- arch/arm64/kernel/smp.c | 2 +- 7 files changed, 160 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h index b813019..88932a9 100644 --- a/arch/arm64/include/asm/acpi.h +++ b/arch/arm64/include/asm/acpi.h @@ -71,10 +71,12 @@ static inline bool acpi_has_cpu_in_madt(void) }

static inline void arch_fix_phys_package_id(int num, u32 slot) { } +void __init acpi_init_cpus(void);

#else static inline bool acpi_psci_present(void) { return false; } static inline bool acpi_psci_use_hvc(void) { return false; } +static inline void acpi_init_cpus(void) { } #endif /* CONFIG_ACPI */

#endif /*_ASM_ACPI_H*/ diff --git a/arch/arm64/include/asm/cpu_ops.h b/arch/arm64/include/asm/cpu_ops.h index 6f8e2ef..5615970 100644 --- a/arch/arm64/include/asm/cpu_ops.h +++ b/arch/arm64/include/asm/cpu_ops.h @@ -66,5 +66,6 @@ struct cpu_operations { extern const struct cpu_operations *cpu_ops[NR_CPUS]; int __init cpu_read_ops(struct device_node *dn, int cpu); void __init cpu_read_bootcpu_ops(void); +const struct cpu_operations *cpu_get_ops(const char *name);

#endif /* ifndef __ASM_CPU_OPS_H */ diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h index 780f82c..bf22650 100644 --- a/arch/arm64/include/asm/smp.h +++ b/arch/arm64/include/asm/smp.h @@ -39,9 +39,10 @@ extern void show_ipi_list(struct seq_file *p, int prec); extern void handle_IPI(int ipinr, struct pt_regs *regs);

/* - * Setup the set of possible CPUs (via set_cpu_possible) + * Discover the set of possible CPUs and determine their + * SMP operations. */ -extern void smp_init_cpus(void); +extern void of_smp_init_cpus(void);

/* * Provide a function to raise an IPI cross call on CPUs in callmap. diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index bdcc9fc..3b4c44b 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -25,6 +25,10 @@ #include <linux/of_fdt.h> #include <linux/smp.h>

+#include <asm/cputype.h> +#include <asm/cpu_ops.h> +#include <asm/smp_plat.h> + int acpi_noirq = 1; /* skip ACPI IRQ initialization */ int acpi_disabled = 1; EXPORT_SYMBOL(acpi_disabled); @@ -32,6 +36,12 @@ EXPORT_SYMBOL(acpi_disabled); int acpi_pci_disabled = 1; /* skip ACPI PCI scan and IRQ initialization */ EXPORT_SYMBOL(acpi_pci_disabled);

+/* Processors with enabled flag and sane MPIDR */ +static int enabled_cpus; + +/* Boot CPU is valid or not in MADT */ +static bool __initdata bootcpu_valid; + static bool __initdata param_acpi_off; static bool __initdata param_acpi_force;

@@ -85,6 +95,129 @@ void __init __acpi_unmap_table(char *map, unsigned long size) early_memunmap(map, size); }

+/** + * acpi_map_gic_cpu_interface - generates a logical cpu number + * and map to MPIDR represented by GICC structure + * @mpidr: CPU's hardware id to register, MPIDR represented in MADT + * @enabled: this cpu is enabled or not + * + * Returns the logical cpu number which maps to MPIDR + */ +static int __init acpi_map_gic_cpu_interface(u64 mpidr, u8 enabled) +{ + int i; + + if (mpidr == INVALID_HWID) { + pr_info("Skip MADT cpu entry with invalid MPIDR\n"); + return -EINVAL; + } + + total_cpus++; + if (!enabled) + return -EINVAL; + + if (enabled_cpus >= NR_CPUS) { + pr_warn("NR_CPUS limit of %d reached, Processor %d/0x%llx ignored.\n", + NR_CPUS, total_cpus, mpidr); + return -EINVAL; + } + + /* Check if GICC structure of boot CPU is available in the MADT */ + if (cpu_logical_map(0) == mpidr) { + if (bootcpu_valid) { + pr_err("Firmware bug, duplicate CPU MPIDR: 0x%llx in MADT\n", + mpidr); + return -EINVAL; + } + + bootcpu_valid = true; + } + + /* + * Duplicate MPIDRs are a recipe for disaster. Scan + * all initialized entries and check for + * duplicates. If any is found just ignore the CPU. + */ + for (i = 1; i < enabled_cpus; i++) { + if (cpu_logical_map(i) == mpidr) { + pr_err("Firmware bug, duplicate CPU MPIDR: 0x%llx in MADT\n", + mpidr); + return -EINVAL; + } + } + + if (!acpi_psci_present()) + return -EOPNOTSUPP; + + cpu_ops[enabled_cpus] = cpu_get_ops("psci"); + /* CPU 0 was already initialized */ + if (enabled_cpus) { + if (!cpu_ops[enabled_cpus]) + return -EINVAL; + + if (cpu_ops[enabled_cpus]->cpu_init(NULL, enabled_cpus)) + return -EOPNOTSUPP; + + /* map the logical cpu id to cpu MPIDR */ + cpu_logical_map(enabled_cpus) = mpidr; + } + + enabled_cpus++; + return enabled_cpus; +} + +static int __init +acpi_parse_gic_cpu_interface(struct acpi_subtable_header *header, + const unsigned long end) +{ + struct acpi_madt_generic_interrupt *processor; + + processor = (struct acpi_madt_generic_interrupt *)header; + + if (BAD_MADT_ENTRY(processor, end)) + return -EINVAL; + + acpi_table_print_madt_entry(header); + + acpi_map_gic_cpu_interface(processor->arm_mpidr & MPIDR_HWID_BITMASK, + processor->flags & ACPI_MADT_ENABLED); + + return 0; +} + +/* Parse GIC cpu interface entries in MADT for SMP init */ +void __init acpi_init_cpus(void) +{ + int count, i; + + /* + * do a partial walk of MADT to determine how many CPUs + * we have including disabled CPUs, and get information + * we need for SMP init + */ + count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT, + acpi_parse_gic_cpu_interface, 0); + + if (!count) { + pr_err("No GIC CPU interface entries present\n"); + return; + } else if (count < 0) { + pr_err("Error parsing GIC CPU interface entry\n"); + return; + } + + if (!bootcpu_valid) { + pr_err("MADT missing boot CPU MPIDR, not enabling secondaries\n"); + return; + } + + for (i = 0; i < enabled_cpus; i++) + set_cpu_possible(i, true); + + /* Make boot-up look pretty */ + pr_info("%d CPUs enabled, %d CPUs total\n", enabled_cpus, total_cpus); +} + static int __init acpi_parse_fadt(struct acpi_table_header *table) { struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table; @@ -96,8 +229,20 @@ static int __init acpi_parse_fadt(struct acpi_table_header *table) * boot protocol configuration data, or we will disable ACPI. */ if (table->revision > 5 || - (table->revision == 5 && fadt->minor_revision >= 1)) - return 0; + (table->revision == 5 && fadt->minor_revision >= 1)) { + /* + * ACPI 5.1 only has two explicit methods to boot up SMP, + * PSCI and Parking protocol, but the Parking protocol is + * only specified for ARMv7 now, so make PSCI as the only + * way for the SMP boot protocol before some updates for + * the Parking protocol spec. + */ + if (acpi_psci_present()) + return 0; + + pr_warn("No PSCI support, will not bring up secondary CPUs\n"); + return -EOPNOTSUPP; + }

pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will disable ACPI\n", table->revision, fadt->minor_revision); diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c index cce9524..fb8ff9b 100644 --- a/arch/arm64/kernel/cpu_ops.c +++ b/arch/arm64/kernel/cpu_ops.c @@ -35,7 +35,7 @@ static const struct cpu_operations *supported_cpu_ops[] __initconst = { NULL, };

-static const struct cpu_operations * __init cpu_get_ops(const char *name) +const struct cpu_operations * __init cpu_get_ops(const char *name) { const struct cpu_operations **ops = supported_cpu_ops;

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index c83e909..4b89e6c 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -412,13 +412,16 @@ void __init setup_arch(char **cmdline_p) if (acpi_disabled) { unflatten_device_tree(); psci_dt_init(); + cpu_read_bootcpu_ops(); +#ifdef CONFIG_SMP + of_smp_init_cpus(); +#endif } else { psci_acpi_init(); + acpi_init_cpus(); }

- cpu_read_bootcpu_ops(); #ifdef CONFIG_SMP - smp_init_cpus(); smp_build_mpidr_hash(); #endif

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 7ae6ee0..5aaf5a4 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -323,7 +323,7 @@ void __init smp_prepare_boot_cpu(void) * cpu logical map array containing MPIDR values related to logical * cpus. Assumes that cpu_logical_map(0) has already been initialized. */ -void __init smp_init_cpus(void) +void __init of_smp_init_cpus(void) { struct device_node *dn = NULL; unsigned int i, cpu = 1;

From: Tomasz Nowicki tomasz.nowicki@linaro.org

ACPI kernel uses MADT table for proper GIC initialization. It needs to parse GIC related subtables, collect CPU interface and distributor addresses and call driver initialization function (which is hardware abstraction agnostic). In a similar way, FDT initialize GICv1/2.

NOTE: This commit allow to initialize GICv1/2 basic functionality. While now simple GICv2 init call is used, any further GIC features require generic infrastructure for proper ACPI irqchip initialization. That mechanism and stacked irqdomains to support GICv2 MSI/vitalization extension, GICv3/4 and its ITS are considered as next steps.

CC: Jason Cooper jason@lakedaemon.net CC: Marc Zyngier marc.zyngier@arm.com CC: Thomas Gleixner tglx@linutronix.de Tested-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com Tested-by: Yijing Wang wangyijing@huawei.com Tested-by: Mark Langsdorf mlangsdo@redhat.com Tested-by: Jon Masters jcm@redhat.com Tested-by: Timur Tabi timur@codeaurora.org Tested-by: Robert Richter rrichter@cavium.com Acked-by: Robert Richter rrichter@cavium.com Signed-off-by: Tomasz Nowicki tomasz.nowicki@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org --- arch/arm64/include/asm/acpi.h | 2 + arch/arm64/kernel/acpi.c | 25 +++++++++ drivers/irqchip/irq-gic.c | 102 +++++++++++++++++++++++++++++++++++ drivers/irqchip/irqchip.c | 3 ++ include/linux/acpi.h | 17 ++++++ include/linux/irqchip/arm-gic-acpi.h | 29 ++++++++++ 6 files changed, 178 insertions(+) create mode 100644 include/linux/irqchip/arm-gic-acpi.h

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h index 5244d11..b71d116 100644 --- a/arch/arm64/include/asm/acpi.h +++ b/arch/arm64/include/asm/acpi.h @@ -13,6 +13,8 @@ #define _ASM_ACPI_H

#include <linux/mm.h> +#include <linux/irqchip/arm-gic-acpi.h> + #include <asm/smp_plat.h> #include <asm/cputype.h>

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index 8a7a089..69cdcee 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -359,3 +359,28 @@ void __init acpi_boot_table_init(void) pr_err("Can't find FADT\n"); } } + +void __init acpi_gic_init(void) +{ + struct acpi_table_header *table; + acpi_status status; + acpi_size tbl_size; + int err; + + if (acpi_disabled) + return; + + status = acpi_get_table_with_size(ACPI_SIG_MADT, 0, &table, &tbl_size); + if (ACPI_FAILURE(status)) { + const char *msg = acpi_format_exception(status); + + pr_err("Failed to get MADT table, %s\n", msg); + return; + } + + err = gic_v2_acpi_init(table); + if (err) + pr_err("Failed to initialize GIC IRQ controller"); + + early_acpi_os_unmap_memory((char *)table, tbl_size); +} diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c index d617ee5..7f874d6 100644 --- a/drivers/irqchip/irq-gic.c +++ b/drivers/irqchip/irq-gic.c @@ -33,12 +33,14 @@ #include <linux/of.h> #include <linux/of_address.h> #include <linux/of_irq.h> +#include <linux/acpi.h> #include <linux/irqdomain.h> #include <linux/interrupt.h> #include <linux/percpu.h> #include <linux/slab.h> #include <linux/irqchip/chained_irq.h> #include <linux/irqchip/arm-gic.h> +#include <linux/irqchip/arm-gic-acpi.h>

#include <asm/cputype.h> #include <asm/irq.h> @@ -1083,3 +1085,103 @@ IRQCHIP_DECLARE(msm_8660_qgic, "qcom,msm-8660-qgic", gic_of_init); IRQCHIP_DECLARE(msm_qgic2, "qcom,msm-qgic2", gic_of_init);

#endif + +#ifdef CONFIG_ACPI +static phys_addr_t dist_phy_base, cpu_phy_base; +static int cpu_base_assigned; + +static int __init +gic_acpi_parse_madt_cpu(struct acpi_subtable_header *header, + const unsigned long end) +{ + struct acpi_madt_generic_interrupt *processor; + phys_addr_t gic_cpu_base; + + processor = (struct acpi_madt_generic_interrupt *)header; + + if (BAD_MADT_ENTRY(processor, end)) + return -EINVAL; + + /* + * There is no support for non-banked GICv1/2 register in ACPI spec. + * All CPU interface addresses have to be the same. + */ + gic_cpu_base = processor->base_address; + if (cpu_base_assigned && gic_cpu_base != cpu_phy_base) + return -EINVAL; + + cpu_phy_base = gic_cpu_base; + cpu_base_assigned = 1; + return 0; +} + +static int __init +gic_acpi_parse_madt_distributor(struct acpi_subtable_header *header, + const unsigned long end) +{ + struct acpi_madt_generic_distributor *dist; + + dist = (struct acpi_madt_generic_distributor *)header; + + if (BAD_MADT_ENTRY(dist, end)) + return -EINVAL; + + dist_phy_base = dist->base_address; + return 0; +} + +int __init +gic_v2_acpi_init(struct acpi_table_header *table) +{ + void __iomem *cpu_base, *dist_base; + int count; + + /* Collect CPU base addresses */ + count = acpi_parse_entries(ACPI_SIG_MADT, + sizeof(struct acpi_table_madt), + gic_acpi_parse_madt_cpu, table, + ACPI_MADT_TYPE_GENERIC_INTERRUPT, 0); + if (count <= 0) { + pr_err("No valid GICC entries exist\n"); + return -EINVAL; + } + + /* + * Find distributor base address. We expect one distributor entry since + * ACPI 5.1 spec neither support multi-GIC instances nor GIC cascade. + */ + count = acpi_parse_entries(ACPI_SIG_MADT, + sizeof(struct acpi_table_madt), + gic_acpi_parse_madt_distributor, table, + ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR, 0); + if (count <= 0) { + pr_err("No valid GICD entries exist\n"); + return -EINVAL; + } else if (count > 1) { + pr_err("More than one GICD entry detected\n"); + return -EINVAL; + } + + cpu_base = ioremap(cpu_phy_base, ACPI_GIC_CPU_IF_MEM_SIZE); + if (!cpu_base) { + pr_err("Unable to map GICC registers\n"); + return -ENOMEM; + } + + dist_base = ioremap(dist_phy_base, ACPI_GICV2_DIST_MEM_SIZE); + if (!dist_base) { + pr_err("Unable to map GICD registers\n"); + iounmap(cpu_base); + return -ENOMEM; + } + + /* + * Initialize zero GIC instance (no multi-GIC support). Also, set GIC + * as default IRQ domain to allow for GSI registration and GSI to IRQ + * number translation (see acpi_register_gsi() and acpi_gsi_to_irq()). + */ + gic_init_bases(0, -1, dist_base, cpu_base, 0, NULL); + irq_set_default_host(gic_data[0].domain); + return 0; +} +#endif diff --git a/drivers/irqchip/irqchip.c b/drivers/irqchip/irqchip.c index 0fe2f71..5855240 100644 --- a/drivers/irqchip/irqchip.c +++ b/drivers/irqchip/irqchip.c @@ -8,6 +8,7 @@ * warranty of any kind, whether express or implied. */

+#include <linux/acpi.h> #include <linux/init.h> #include <linux/of_irq.h> #include <linux/irqchip.h> @@ -26,4 +27,6 @@ extern struct of_device_id __irqchip_of_table[]; void __init irqchip_init(void) { of_irq_init(__irqchip_of_table); + + acpi_irq_init(); } diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 121f532..7b13eb2 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -549,6 +549,23 @@ static inline int acpi_device_modalias(struct device *dev,

#endif /* !CONFIG_ACPI */

+#if defined(CONFIG_ACPI) && defined(CONFIG_ARM64) +static inline void acpi_irq_init(void) +{ + /* + * Hardcode ACPI IRQ chip initialization to GICv2 for now. + * Proper irqchip infrastructure will be implemented along with + * incoming GICv2m|GICv3|ITS bits. + */ + acpi_gic_init(); +} +#else +static inline void acpi_irq_init(void) +{ + return; +} +#endif + #ifdef CONFIG_ACPI void acpi_os_set_prepare_sleep(int (*func)(u8 sleep_state, u32 pm1a_ctrl, u32 pm1b_ctrl)); diff --git a/include/linux/irqchip/arm-gic-acpi.h b/include/linux/irqchip/arm-gic-acpi.h new file mode 100644 index 0000000..d5b2c79 --- /dev/null +++ b/include/linux/irqchip/arm-gic-acpi.h @@ -0,0 +1,29 @@ +/* + * Copyright (C) 2014, Linaro Ltd. + * Author: Tomasz Nowicki tomasz.nowicki@linaro.org + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef ARM_GIC_ACPI_H_ +#define ARM_GIC_ACPI_H_ + +#ifdef CONFIG_ACPI + +/* + * Hard code here, we can not get memory size from MADT (but FDT does), + * Actually no need to do that, because this size can be inferred + * from GIC spec. + */ +#define ACPI_GICV2_DIST_MEM_SIZE (SZ_4K) +#define ACPI_GIC_CPU_IF_MEM_SIZE (SZ_8K) + +struct acpi_table_header; + +int gic_v2_acpi_init(struct acpi_table_header *table); +void acpi_gic_init(void); +#endif + +#endif /* ARM_GIC_ACPI_H_ */

From: Al Stone al.stone@linaro.org

ACPI reduced hardware mode is disabled by default, but ARM64 can only run properly in ACPI hardware reduced mode, so select ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64.

CC: Catalin Marinas catalin.marinas@arm.com CC: Will Deacon will.deacon@arm.com Reviewed-by: Grant Likely grant.likely@linaro.org Tested-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com Tested-by: Yijing Wang wangyijing@huawei.com Tested-by: Mark Langsdorf mlangsdo@redhat.com Tested-by: Jon Masters jcm@redhat.com Tested-by: Timur Tabi timur@codeaurora.org Tested-by: Robert Richter rrichter@cavium.com Acked-by: Robert Richter rrichter@cavium.com Signed-off-by: Al Stone al.stone@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org --- arch/arm64/Kconfig | 1 + 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index b1f9a20..c19ae5d 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1,5 +1,6 @@ config ARM64 def_bool y + select ACPI_REDUCED_HARDWARE_ONLY if ACPI select ARCH_BINFMT_ELF_RANDOMIZE_PIE select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select ARCH_HAS_GCOV_PROFILE_ALL

From: Graeme Gregory graeme.gregory@linaro.org

Add documentation for the guidelines of how to use ACPI on ARM64.

Reviewed-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com Reviewed-by: Yi Li phoenix.liyi@huawei.com Reviewed-by: Mark Langsdorf mlangsdo@redhat.com Reviewed-by: Ashwin Chaugule ashwinc@codeaurora.org Acked-by: Robert Richter rrichter@cavium.com Signed-off-by: Graeme Gregory graeme.gregory@linaro.org Signed-off-by: Al Stone al.stone@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org --- Documentation/arm64/arm-acpi.txt | 506 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 506 insertions(+) create mode 100644 Documentation/arm64/arm-acpi.txt

diff --git a/Documentation/arm64/arm-acpi.txt b/Documentation/arm64/arm-acpi.txt new file mode 100644 index 0000000..24cf832 --- /dev/null +++ b/Documentation/arm64/arm-acpi.txt @@ -0,0 +1,506 @@ +ACPI on ARMv8 Servers +--------------------- +ACPI can be used for ARMv8 general purpose servers designed to follow +the ARM SBSA (Server Base System Architecture) [0] and SBBR (Server +Base Boot Requirements) [1] specifications. Please note that the SBBR +can be retrieved simply by visiting [1], but the SBSA is currently only +available to those with an ARM login due to ARM IP licensing concerns. + +The ARMv8 kernel implements the reduced hardware model of ACPI version +5.1 or later. Links to the specification and all external documents +it refers to are managed by the UEFI Forum. The specification is +available at http://www.uefi.org/specifications and documents referenced +by the specification can be found via http://www.uefi.org/acpi. + +If an ARMv8 system does not meet the requirements of the SBSA and SBBR, +or cannot be described using the mechanisms defined in the required ACPI +specifications, then ACPI may not be a good fit for the hardware. + +While the documents mentioned above set out the requirements for building +industry-standard ARMv8 servers, they also apply to more than one operating +system. The purpose of this document is to describe the interaction between +ACPI and Linux only, on an ARMv8 system -- that is, what Linux expects of +ACPI and what ACPI can expect of Linux. + + +Why ACPI on ARM? +---------------- +Before examining the details of the interface between ACPI and Linux, it is +useful to understand why ACPI is being used. Several technologies already +exist in Linux for describing non-enumerable hardware, after all. In this +section we summarize a blog post [2] from Grant Likely that outlines the +reasoning behind ACPI on ARMv8 servers. Actually, we snitch a good portion +of the summary text almost directly, to be honest. + +The short form of the rationale for ACPI on ARM is: + +-- ACPI’s bytecode (AML) allows the platform to encode hardware behavior, + while DT explicitly does not support this. For hardware vendors, being + able to encode behavior is a key tool used in supporting operating + system releases on new hardware. + +-- ACPI’s OSPM defines a power management model that constrains what the + platform is allowed to do into a specific model, while still providing + flexibility in hardware design. + +-- In the enterprise server environment, ACPI has established bindings (such + as for RAS) which are currently used in production systems. DT does not. + Such bindings could be defined in DT at some point, but doing so means ARM + and x86 would end up using completely different code paths in both firmware + and the kernel. + +-- Choosing a single interface to describe the abstraction between a platform + and an OS is important. Hardware vendors would not be required to implement + both DT and ACPI if they want to support multiple operating systems. And, + agreeing on a single interface instead of being fragmented into per OS + interfaces makes for better interoperability overall. + +-- The new ACPI governance process works well and Linux is now at the same + table as hardware vendors and other OS vendors. In fact, there is no + longer any reason to feel that ACPI is only belongs to Windows or that + Linux is in any way secondary to Microsoft in this arena. The move of + ACPI governance into the UEFI forum has significantly opened up the + specification development process, and currently, a large portion of the + changes being made to ACPI is being driven by Linux. + +Key to the use of ACPI is the support model. For servers in general, the +responsibility for hardware behaviour cannot solely be the domain of the +kernel, but rather must be split between the platform and the kernel, in +order to allow for orderly change over time. ACPI frees the OS from needing +to understand all the minute details of the hardware so that the OS doesn’t +need to be ported to each and every device individually. It allows the +hardware vendors to take responsibility for power management behaviour without +depending on an OS release cycle which is not under their control. + +ACPI is also important because hardware and OS vendors have already worked +out the mechanisms for supporting a general purpose computing ecosystem. The +infrastructure is in place, the bindings are in place, and the processes are +in place. DT does exactly what Linux needs it to when working with vertically +integrated devices, but there are no good processes for supporting what the +server vendors need. Linux could potentially get there with DT, but doing so +really just duplicates something that already works. ACPI already does what +the hardware vendors need, Microsoft won’t collaborate on DT, and hardware +vendors would still end up providing two completely separate firmware +interfaces -- one for Linux and one for Windows. + + +Kernel Compatibility +-------------------- +One of the primary motivations for ACPI is standardization, and using that +to provide backward compatibility for Linux kernels. In the server market, +software and hardware are often used for long periods. ACPI allows the +kernel and firmware to agree on a consistent abstraction that can be +maintained over time, even as hardware or software change. As long as the +abstraction is supported, systems can be updated without necessarily having +to replace the kernel. + +When a Linux driver or subsystem is first implemented using ACPI, it by +definition ends up requiring a specific version of the ACPI specification +-- it's baseline. ACPI firmware must continue to work, even though it may +not be optimal, with the earliest kernel version that first provides support +for that baseline version of ACPI. There may be a need for additional drivers, +but adding new functionality (e.g., CPU power management) should not break +older kernel versions. Further, ACPI firmware must also work with the most +recent version of the kernel. + + +Relationship with Device Tree +----------------------------- +ACPI support in drivers and subsystems for ARMv8 should never be mutually +exclusive with DT support at compile time. + +At boot time the kernel will only use one description method depending on +parameters passed from the bootloader (including kernel bootargs). + +Regardless of whether DT or ACPI is used, the kernel must always be capable +of booting with either scheme (in kernels with both schemes enabled at compile +time). + + +Booting using ACPI tables +------------------------- +The only defined method for passing ACPI tables to the kernel on ARMv8 +is via the UEFI system configuration table. Just so it is explicit, this +means that ACPI is only supported on platforms that boot via UEFI. + +When an ARMv8 system boots, it can either have DT information, ACPI tables, +or in some very unusual cases, both. If no command line parameters are used, +the kernel will try to use DT for device enumeration; if there is no DT +present, the kernel will try to use ACPI tables, but only if they are present. +In neither is available, the kernel will not boot. If acpi=force is used +on the command line, the kernel will attempt to use ACPI tables first, but +fall back to DT if there are no ACPI tables present. The basic idea is that +the kernel will not fail to boot unless it absolutely has no other choice. + +Processing of ACPI tables may be disabled by passing acpi=off on the kernel +command line; this is the default behavior. + +In order for the kernel to load and use ACPI tables, the UEFI implementation +MUST set the ACPI_20_TABLE_GUID to point to the RSDP table (the table with +the ACPI signature "RSD PTR "). If this pointer is incorrect and acpi=force +is used, the kernel will disable ACPI and try to use DT to boot instead; the +kernel has, in effect, determined that ACPI tables are not present at that +point. + +If the pointer to the RSDP table is correct, the table will be mapped into +the kernel by the ACPI core, using the address provided by UEFI. + +The ACPI core will then locate and map in all other ACPI tables provided by +using the addresses in the RSDP table to find the XSDT (eXtended System +Description Table). The XSDT in turn provides the addresses to all other +ACPI tables provided by the system firmware; the ACPI core will then traverse +this table and map in the tables listed. + +The ACPI core will ignore any provided RSDT (Root System Description Table). +RSDTs have been deprecated and are ignored on arm64 since they only allow +for 32-bit addresses. + +Further, the ACPI core will only use the 64-bit address fields in the FADT +(Fixed ACPI Description Table). Any 32-bit address fields in the FADT will +be ignored on arm64. + +Hardware reduced mode (see Section 4.1 of the ACPI 5.1 specification) will +be enforced by the ACPI core on arm64. Doing so allows the ACPI core to +run less complex code since it no longer has to provide support for legacy +hardware from other architectures. Any fields that are not to be used for +hardware reduced mode must be set to zero. + +For the ACPI core to operate properly, and in turn provide the information +the kernel needs to configure devices, it expects to find the following +tables (all section numbers refer to the ACPI 5.1 specfication): + + -- RSDP (Root System Description Pointer), section 5.2.5 + + -- XSDT (eXtended System Description Table), section 5.2.8 + + -- FADT (Fixed ACPI Description Table), section 5.2.9 + + -- DSDT (Differentiated System Description Table), section + 5.2.11.1 + + -- MADT (Multiple APIC Description Table), section 5.2.12 + + -- GTDT (Generic Timer Description Table), section 5.2.24 + + -- If PCI is supported, the MCFG (Memory mapped ConFiGuration + Table), section 5.2.6, specifically Table 5-31. + +If the above tables are not all present, the kernel may or may not be +able to boot properly since it may not be able to configure all of the +devices available. + + +ACPI Detection +-------------- +Drivers should determine their probe() type by checking for a null +value for ACPI_HANDLE, or checking .of_node, or other information in +the device structure. This is detailed further in the "Driver +Recommendations" section. + +In non-driver code, if the presence of ACPI needs to be detected at +runtime, then check the value of acpi_disabled. If CONFIG_ACPI is not +set, acpi_disabled will always be 1. + + +Device Enumeration +------------------ +Device descriptions in ACPI should use standard recognized ACPI interfaces. +These may contain less information than is typically provided via a Device +Tree description for the same device. This is also one of the reasons that +ACPI can be useful -- the driver takes into account that it may have less +detailed information about the device and uses sensible defaults instead. +If done properly in the driver, the hardware can change and improve over +time without the driver having to change at all. + +Clocks provide an excellent example. In DT, clocks need to be specified +and the drivers need to take them into account. In ACPI, the assumption +is that UEFI will leave the device in a reasonable default state, including +any clock settings. If for some reason the driver needs to change a clock +value, this can be done in an ACPI method; all the driver needs to do is +invoke the method and not concern itself with what the method needs to do +to change the clock. Changing the hardware can then take place over time +by changing what the ACPI method does, and not the driver. + +In DT, the parameters needed by the driver to set up clocks as in the example +above are known as "bindings"; in ACPI, these are known as "Device Properties" +and provided to a driver via the _DSD object. + +ACPI tables are described with a formal language called ASL, the ACPI +Source Language (section 19 of the specification). This means that there +are always multiple ways to describe the same thing -- including device +properties. For example, device properties could use an ASL construct +that looks like this: Name(KEY0, "value0"). An ACPI device driver would +then retrieve the value of the property by evaluating the KEY0 object. +However, using Name() this way has multiple problems: (1) ACPI limits +names ("KEY0") to four characters unlike DT; (2) there is no industry +wide registry that maintains a list of names, minimzing re-use; (3) +there is also no registry for the definition of property values ("value0"), +again making re-use difficult; and (4) how does one maintain backward +compatibility as new hardware comes out? The _DSD method was created +to solve precisely these sorts of problems; Linux drivers should ALWAYS +use the _DSD method for device properties and nothing else. + +The _DSM object (ACPI Section 9.14.1) could also be used for conveying +device properties to a driver. Linux drivers should only expect it to +be used if _DSD cannot represent the data required, and there is no way +to create a new UUID for the _DSD object. Note that there is even less +regulation of the use of _DSM than there is of _DSD. Drivers that depend +on the contents of _DSM objects will be more difficult to maintain over +time because of this; as of this writing, the use of _DSM is the cause +of quite a few firmware problems and is not recommended. + +Drivers should look for device properties in the _DSD object ONLY; the _DSD +object is described in the ACPI specification section 6.2.5, but this only +describes how to define the structure of an object returned via _DSD, and +how specific data structures are defined by specific UUIDs. Linux should +only use the _DSD Device Properties UUID [5]: + + -- UUID: daffd814-6eba-4d8c-8a91-bc9bbf4aa301 + + -- http://www.uefi.org/sites/default/files/resources/_DSD-device-properties-UUI... + +The UEFI Forum provides a mechanism for registering device properties [4] +so that they may be used across all operating systems supporting ACPI. +Device properties that have not been registered with the UEFI Forum should +not be used. + +Before creating new device properties, check to be sure that they have not +been defined before and either registered in the Linux kernel documentation +as DT bindings, or the UEFI Forum as device properties. While we do not want +to simply move all DT bindings into ACPI device properties, we can learn from +what has been previously defined. + +If it is necessary to define a new device property, or if it makes sense to +synthesize the definition of a binding so it can be used in any firmware, +both DT bindings and ACPI device properties for device drivers have review +processes. Use them both. When the driver itself is submitted for review +to the Linux mailing lists, the device property definitions needed must be +submitted at the same time. A driver that supports ACPI and uses device +properties will not be considered complete without their definitions. Once +the device property has been accepted by the Linux community, it must be +registered with the UEFI Forum [4], which will review it again for consistency +within the registry. This may require iteration. The UEFI Forum, though, +will always be the canonical site for device property definitions. + +It may make sense to provide notice to the UEFI Forum that there is the +intent to register a previously unused device property name as a means of +reserving the name for later use. Other operating system vendors will +also be submitting registration requests and this may help smooth the +process. + +Once registration and review have been completed, the kernel provides an +interface for looking up device properties in a manner independent of +whether DT or ACPI is being used. This API should be used [6]; it can +eliminate some duplication of code paths in driver probing functions and +discourage divergence between DT bindings and ACPI device properties. + + +Programmable Power Control Resources +------------------------------------ +Programmable power control resources include such resources as voltage/current +providers (regulators) and clock sources. + +With ACPI, the kernel clock and regulator framework is not expected to be used +at all. + +The kernel assumes that power control of these resources is represented with +Power Resource Objects (ACPI section 7.1). The ACPI core will then handle +correctly enabling and disabling resources as they are needed. In order to +get that to work, ACPI assumes each device has defined D-states and that these +can be controlled through the optional ACPI methods _PS0, _PS1, _PS2, and _PS3; +in ACPI, _PS0 is the method to invoke to turn a device full on, and _PS3 is for +turning a device full off. + +There are two options for using those Power Resources. They can: + + -- be managed in a _PSx method which gets called on entry to power + state Dx. + + -- be declared separately as power resources with their own _ON and _OFF + methods. They are then tied back to D-states for a particular device + via _PRx which specifies which power resources a device needs to be on + while in Dx. Kernel then tracks number of devices using a power resource + and calls _ON/_OFF as needed. + +The kernel ACPI code will also assume that the _PSx methods follow the normal +ACPI rules for such methods: + + -- If either _PS0 or _PS3 is implemented, then the other method must also + be implemented. + + -- If a device requires usage or setup of a power resource when on, the ASL + should organize that it is allocated/enabled using the _PS0 method. + + -- Resources allocated or enabled in the _PS0 method should be disabled + or de-allocated in the _PS3 method. + + -- Firmware will leave the resources in a reasonable state before handing + over control to the kernel. + +Such code in _PSx methods will of course be very platform specific. But, +this allows the driver to abstract out the interface for operating the device +and avoid having to read special non-standard values from ACPI tables. Further, +abstracting the use of these resources allows the hardware to change over time +without requiring updates to the driver. + + +Clocks +------ +ACPI makes the assumption that clocks are initialized by the firmware -- +UEFI, in this case -- to some working value before control is handed over +to the kernel. This has implications for devices such as UARTs, or SoC-driven +LCD displays, for example. + +When the kernel boots, the clocks are assumed to be set to reasonable +working values. If for some reason the frequency needs to change -- e.g., +throttling for power management -- the device driver should expect that +process to be abstracted out into some ACPI method that can be invoked +(please see the ACPI specification for further recommendations on standard +methods to be expected). The only exceptions to this are CPU clocks where +CPPC provides a much richer interface than ACPI methods. If the clocks +are not set, there is no direct way for Linux to control them. + +If an SoC vendor wants to provide fine-grained control of the system clocks, +they could do so by providing ACPI methods that could be invoked by Linux +drivers. However, this is NOT recommended and Linux drivers should NOT use +such methods, even if they are provided. Such methods are not currently +standardized in the ACPI specification, and using them could tie a kernel +to a very specific SoC, or tie an SoC to a very specific version of the +kernel, both of which we are trying to avoid. + + +Driver Recommendations +---------------------- +DO NOT remove any DT handling when adding ACPI support for a driver. The +same device may be used on many different systems. + +DO try to structure the driver so that it is data-driven. That is, set up +a struct containing internal per-device state based on defaults and whatever +else must be discovered by the driver probe function. Then, have the rest +of the driver operate off of the contents of that struct. Doing so should +allow most divergence between ACPI and DT functionality to be kept local to +the probe function instead of being scattered throughout the driver. For +example: + +static int device_probe_dt(struct platform_device *pdev) +{ + /* DT specific functionality */ + ... +} + +static int device_probe_acpi(struct platform_device *pdev) +{ + /* ACPI specific functionality */ + ... +} + +static int device_probe(struct platform_device *pdev) +{ + ... + struct device_node node = pdev->dev.of_node; + ... + + if (node) + ret = device_probe_dt(pdev); + else if (ACPI_HANDLE(&pdev->dev)) + ret = device_probe_acpi(pdev); + else + /* other initialization */ + ... + /* Continue with any generic probe operations */ + ... +} + +DO keep the MODULE_DEVICE_TABLE entries together in the driver to make it +clear the different names the driver is probed for, both from DT and from +ACPI: + +static struct of_device_id virtio_mmio_match[] = { + { .compatible = "virtio,mmio", }, + { } +}; +MODULE_DEVICE_TABLE(of, virtio_mmio_match); + +static const struct acpi_device_id virtio_mmio_acpi_match[] = { + { "LNRO0005", }, + { } +}; +MODULE_DEVICE_TABLE(acpi, virtio_mmio_acpi_match); + + +ASWG +---- +The ACPI specification changes regularly. During the year 2014, for instance, +version 5.1 was released and version 6.0 substantially completed, with most of +the changes being driven by ARM-specific requirements. Proposed changes are +presented and discussed in the ASWG (ACPI Specification Working Group) which +is a part of the UEFI Forum. + +Participation in this group is open to all UEFI members. Please see +http://www.uefi.org/workinggroup for details on group membership. + +It is the intent of the ARMv8 ACPI kernel code to follow the ACPI specification +as closely as possible, and to only implement functionality that complies with +the released standards from UEFI ASWG. As a practical matter, there will be +vendors that provide bad ACPI tables or violate the standards in some way. +If this is because of errors, quirks and fixups may be necessary, but will +be avoided if possible. If there are features missing from ACPI that preclude +it from being used on a platform, ECRs (Engineering Change Requests) should be +submitted to ASWG and go through the normal approval process; for those that +are not UEFI members, many other members of the Linux community are and would +likely be willing to assist in submitting ECRs. + + +Linux Code +---------- +Individual items specific to Linux on ARM, contained in the the Linux +source code, are in the list that follows: + +ACPI_OS_NAME This macro defines the string to be returned when + an ACPI method invokes the _OS method. On ARM64 + systems, this macro will be "Linux" by default. + The command line parameter acpi_os=<string> + can be used to set it to some other value. The + default value for other architectures is "Microsoft + Windows NT", for example. + +ACPI Objects +------------ +Detailed expectations for ACPI tables and object are listed in the file +Documentation/arm64/acpi_object_usage.txt. + + +References +---------- +[0] http://silver.arm.com -- document ARM-DEN-0029, or newer + "Server Base System Architecture", version 2.3, dated 27 Mar 2014 + +[1] http://infocenter.arm.com/help/topic/com.arm.doc.den0044a/Server_Base_Boot_R... + Document ARM-DEN-0044A, or newer: "Server Base Boot Requirements, System + Software on ARM Platforms", dated 16 Aug 2014 + +[2] http://www.secretlab.ca/archives/151, 10 Jan 2015, Copyright (c) 2015, + Linaro Ltd., written by Grant Likely. A copy of the verbatim text (apart + from formatting) is also in Documentation/arm64/why_use_acpi.txt. + +[3] AMD ACPI for Seattle platform documentation: + http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2012/10/Seattle_ACPI_... + +[4] http://www.uefi.org/acpi -- please see the link for the "ACPI _DSD Device + Property Registry Instructions" + +[5] http://www.uefi.org/acpi -- please see the link for the "_DSD (Device + Specific Data) Implementation Guide" + +[6] Kernel code for the unified device property interface can be found in + include/linux/property.h and drivers/base/property.c. + + +Authors +------- +Al Stone al.stone@linaro.org +Graeme Gregory graeme.gregory@linaro.org +Hanjun Guo hanjun.guo@linaro.org + +Grant Likely grant.likely@linaro.org, for the "Why ACPI on ARM?" section +