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 bfcb1a6..d6c35a7 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 40e0924..c5a9b97 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();