On 2014年09月15日 15:05, Olof Johansson wrote:
On Fri, Sep 12, 2014 at 10:00:10PM +0800, Hanjun Guo wrote:
Introduce a new function map_gicc_mpidr() to allow MPIDRs to be obtained from the GICC Structure introduced by ACPI 5.1.
MPIDR is the CPU hardware ID as local APIC ID on x86 platform, so we use MPIDR not the GIC CPU interface ID to identify CPUs.
Signed-off-by: Hanjun Guo hanjun.guo@linaro.org
arch/arm64/include/asm/acpi.h | 32 ++++++++++++++++++++++++++++++++ arch/arm64/kernel/acpi.c | 1 - drivers/acpi/processor_core.c | 37 +++++++++++++++++++++++++++++++++++++ 3 files changed, 69 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h index da8f74a..2c48f70e 100644 --- a/arch/arm64/include/asm/acpi.h +++ b/arch/arm64/include/asm/acpi.h @@ -12,6 +12,8 @@ #ifndef _ASM_ACPI_H #define _ASM_ACPI_H +#include <asm/smp_plat.h>
/* Basic configuration for ACPI */ #ifdef CONFIG_ACPI #define acpi_strict 1 /* No out-of-spec workarounds on ARM64 */ @@ -38,6 +40,36 @@ static inline void disable_acpi(void) acpi_noirq = 1; } +/* MPIDR value provided in GICC structure is 64 bits, but
- the acpi processor driver use the 32 bits cpu hardware
- ID (apic_id on intel platform) everywhere, it is pretty
- hard to modify the acpi processor driver to accept the
- 64 bits MPIDR value, at the same time, only 32 bits of
- the MPIDR is used in the 64 bits MPIDR, just pack the
- Affx fields into a single 32 bit identifier to accommodate
- the acpi processor drivers.
- */
This is a pretty run-on comment.
I'd much rather value something like:
Existing apic_id is 32-bit, to conform to the same datatype we need to repack the GICC structure MPIDR.
The two formats are:
<show how the 64-bit format is laid out> <show how the 32-bit format is laid out>
+static inline u32 pack_mpidr_into_32_bits(u64 mpidr)
That's a pretty long name for an exported function.
+{
- /*
* Bits [0:7] Aff0;* Bits [8:15] Aff1;* Bits [16:23] Aff2;* Bits [32:39] Aff3;*/With the format description above added, then this comment can be removed.
ok, I will update it.
- return (u32) ((mpidr & 0xff00000000) >> 8) | mpidr;
+}
+/*
- The ACPI processor driver for ACPI core code needs this macro
- to find out this cpu was already mapped (mapping from CPU hardware
- ID to CPU logical ID) or not.
- cpu_logical_map(cpu) is the mapping of MPIDR and the logical cpu,
- and MPIDR is the cpu hardware ID we needed to pack.
- */
+#define cpu_physical_id(cpu) pack_mpidr_into_32_bits(cpu_logical_map(cpu))
/*
- 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 644b8b8..2ef8721 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -24,7 +24,6 @@ #include <linux/bootmem.h> #include <linux/smp.h> -#include <asm/smp_plat.h> #include <asm/cputype.h> #include <asm/cpu_ops.h> diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c index e32321c..4007313 100644 --- a/drivers/acpi/processor_core.c +++ b/drivers/acpi/processor_core.c @@ -64,6 +64,38 @@ static int map_lsapic_id(struct acpi_subtable_header *entry, return 0; } +/*
- On ARM platform, MPIDR value is the hardware ID as apic ID
- on Intel platforms
- */
+static int map_gicc_mpidr(struct acpi_subtable_header *entry,
int device_declaration, u32 acpi_id, int *mpidr)+{
- struct acpi_madt_generic_interrupt *gicc =
container_of(entry, struct acpi_madt_generic_interrupt, header);- if (!(gicc->flags & ACPI_MADT_ENABLED))
return -ENODEV;- /* In the GIC interrupt model, logical processors are
* required to have a Processor Device object in the DSDT,* so we should check device_declaration here*/- if (device_declaration && (gicc->uid == acpi_id)) {
/** Only bits [0:7] Aff0, bits [8:15] Aff1, bits [16:23] Aff2* and bits [32:39] Aff3 are meaningful, so pack the Affx* fields into a single 32 bit identifier to accommodate the* acpi processor drivers.*/Here's duplicated information again. Reusing the same macro as in the header file would help overall readability, I think.
The problem is that it will cause compile error on x86 and ia64 platform, it is ARM64 specific only.
*mpidr = ((gicc->arm_mpidr & 0xff00000000) >> 8)| gicc->arm_mpidr;return 0;- }
- return -EINVAL;
+}