On 2014-8-18 22:27, Catalin Marinas wrote:
On Mon, Aug 04, 2014 at 04:28:12PM +0100, Hanjun Guo wrote:
There are two flags: PSCI_COMPLIANT and PSCI_USE_HVC. When set, the former signals to the OS that the hardware is PSCI compliant.
Actually it signals that the firmware is PSCI compliant. The hardware doesn't care much.
Right, I will update it.
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h index 6400312..6e04868 100644 --- a/arch/arm64/include/asm/acpi.h +++ b/arch/arm64/include/asm/acpi.h @@ -19,6 +19,18 @@ 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);
+}
Do we actually need !! here? Shouldn't the compiler figure out conversion to bool automatically?
I thought !! will explicitly show that it's a bool value and improve the readability of the code, but I'm ok to remove !! here.
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index 9cf9127..69a315d 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -11,6 +11,8 @@
- published by the Free Software Foundation.
*/ +#define pr_fmt(fmt) "ACPI: " fmt
#include <linux/init.h> #include <linux/acpi.h> #include <linux/cpumask.h> @@ -47,6 +49,26 @@ void __init __acpi_unmap_table(char *map, unsigned long size) 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 version,
* and there is a minor version of FADT which was introduced
* by ACPI 5.1, we only deal with ACPI 5.1 or higher version
* to get arm boot flags, or we will disable ACPI.
*/
- if (table->revision < 5 || fadt->minor_revision < 1) {
If we ever get revision 6.0, this would trigger.
Yes, good catch, actually I already fixed that in my local git repo,
+ if (table->revision > 5 || + (table->revision == 5 && fadt->minor_revision >= 1)) { + return 0; + } else { + pr_info("FADT revision is %d.%d, no PSCI support, should be 5.1 or higher\n", + table->revision, fadt->minor_revision); + disable_acpi(); + return -EINVAL; + }
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 85c6326..dfc4e4f3 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -395,6 +395,8 @@ void __init setup_arch(char **cmdline_p) efi_idmap_init(); cpu_logical_map(0) = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;
- acpi_boot_init();
- unflatten_device_tree();
Unless that's changed in a subsequent patch, do we still need to call unflatten_device_tree() if ACPI was successful?
No, we don't. in [PATCH v2 16/18], we will not call unflatten_device_tree() if ACPI is successful. Since the CONFIG_ACPI is not enabled for ARM64 (will enable it in the last patch), so acpi_boot_init() is a stub empty function here.
psci_init();
I would also rename this to something like psci_dt_init() and move the acpi_disabled check here rather than in the callee.
thanks for the suggestion, I will update my patch :)
Thanks Hanjun