From mboxrd@z Thu Jan 1 00:00:00 1970 From: hanjun.guo@linaro.org (Hanjun Guo) Date: Fri, 25 Jul 2014 18:51:37 +0800 Subject: [PATCH 10/19] ARM64 / ACPI: Get the enable method for SMP initialization in ACPI way In-Reply-To: <20140724154745.GD26190@leverpostej> References: <1406206825-15590-1-git-send-email-hanjun.guo@linaro.org> <1406206825-15590-11-git-send-email-hanjun.guo@linaro.org> <20140724154745.GD26190@leverpostej> Message-ID: <53D236B9.7000302@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 2014-7-24 23:47, Mark Rutland wrote: > On Thu, Jul 24, 2014 at 02:00:16PM +0100, Hanjun Guo wrote: >> ACPI 5.1 only has two explicit methods to boot up SMP, >> PSCI and Parking protocol, but the Parking protocol is >> only suitable 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. >> >> Signed-off-by: Hanjun Guo >> Signed-off-by: Tomasz Nowicki >> --- >> arch/arm64/include/asm/acpi.h | 21 +++++++++++++++ >> arch/arm64/include/asm/cpu_ops.h | 9 ++++++- >> arch/arm64/include/asm/smp.h | 2 +- >> arch/arm64/kernel/acpi.c | 9 +++++++ >> arch/arm64/kernel/cpu_ops.c | 52 ++++++++++++++++++++++++++++++++++---- >> arch/arm64/kernel/smp.c | 29 +++++++++++++++++++-- >> 6 files changed, 113 insertions(+), 9 deletions(-) [...] >> /* >> - * Setup the set of possible CPUs (via set_cpu_possible) >> + * Platform specific SMP operations >> */ >> extern void smp_init_cpus(void); > > While the originial comment is out of date, the new form is plain wrong. > > Something like "Discover the set of possible CPUs and determine their > SMP operations" would be a better description of what's going on here. Agreed. > >> >> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c >> index ff0f6a0..2af6662 100644 >> --- a/arch/arm64/kernel/acpi.c >> +++ b/arch/arm64/kernel/acpi.c >> @@ -184,6 +184,15 @@ static int __init acpi_parse_madt_gic_cpu_interface_entries(void) >> return 0; >> } >> >> +/* Protocol to bring up secondary CPUs */ >> +enum acpi_smp_boot_protocol smp_boot_protocol(void) >> +{ >> + if (acpi_psci_present) >> + return ACPI_SMP_BOOT_PSCI; >> + else >> + return ACPI_SMP_BOOT_PARKING_PROTOCOL; >> +} >> + >> static int __init acpi_parse_fadt(struct acpi_table_header *table) >> { >> struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table; >> diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c >> index d62d12f..4d9b3cf 100644 >> --- a/arch/arm64/kernel/cpu_ops.c >> +++ b/arch/arm64/kernel/cpu_ops.c >> @@ -16,11 +16,13 @@ >> * along with this program. If not, see . >> */ >> >> -#include >> -#include >> #include >> #include >> #include >> +#include >> + >> +#include >> +#include > > Was the header move just for consistency with other files, or is there > some ordering requirement here? Ordering requirement, it will meet compile error for "return -ENODEV;" in the head file which I introduced, I know I can include the right head file in asm/cpu_ops.h, but I think move the asm/xx.h after the include of linux/xx.h would be fine. > >> >> extern const struct cpu_operations smp_spin_table_ops; >> extern const struct cpu_operations cpu_psci_ops; >> @@ -52,7 +54,7 @@ static const struct cpu_operations * __init cpu_get_ops(const char *name) >> /* >> * Read a cpu's enable method from the device tree and record it in cpu_ops. >> */ >> -int __init cpu_read_ops(struct device_node *dn, int cpu) >> +int __init cpu_of_read_ops(struct device_node *dn, int cpu) >> { >> const char *enable_method = of_get_property(dn, "enable-method", NULL); >> if (!enable_method) { >> @@ -76,12 +78,52 @@ int __init cpu_read_ops(struct device_node *dn, int cpu) >> return 0; >> } >> >> +#ifdef CONFIG_ACPI >> +/* >> + * Read a cpu's enable method in the ACPI way and record it in cpu_ops. >> + */ >> +int __init cpu_acpi_read_ops(int cpu) >> +{ >> + /* >> + * For ACPI 5.1, only two kind of methods are provided, >> + * Parking protocol and PSCI, but Parking protocol is >> + * used on ARMv7 only, so make PSCI as the only method >> + * for SMP initialization before the ACPI spec or Parking >> + * protocol spec is updated. >> + */ > > That comment is a little misleading. The parking protocol is _specified_ > for ARMv7 only. Agreed. But I'm just wondering if the Parking protocol is modified and then support ARMv8, how to describe it in the comments? > >> + switch (smp_boot_protocol()) { >> + case ACPI_SMP_BOOT_PSCI: >> + cpu_ops[cpu] = cpu_get_ops("psci"); >> + break; >> + case ACPI_SMP_BOOT_PARKING_PROTOCOL: >> + default: >> + cpu_ops[cpu] = NULL; >> + break; >> + } >> + >> + if (!cpu_ops[cpu]) { >> + pr_warn("CPU %d: unsupported enable-method, only PSCI is supported\n", >> + cpu); >> + return -EOPNOTSUPP; >> + } > > That's going to require changes as things get updated, and > "enable-method" is a term from DT rather than ACPI. > > How about: > > "CPU%d: boot protocol unsupported or unknown\n". Pretty fine to me :) Thanks Hanjun