From mboxrd@z Thu Jan 1 00:00:00 1970 From: Geoff Levand Subject: Re: [PATCH 10/19] ARM64 / ACPI: Get the enable method for SMP initialization in ACPI way Date: Thu, 31 Jul 2014 11:52:04 -0700 Message-ID: <1406832724.8971.29.camel@smoke> References: <1406206825-15590-1-git-send-email-hanjun.guo@linaro.org> <1406206825-15590-11-git-send-email-hanjun.guo@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from bombadil.infradead.org ([198.137.202.9]:41704 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952AbaGaSwN (ORCPT ); Thu, 31 Jul 2014 14:52:13 -0400 In-Reply-To: <1406206825-15590-11-git-send-email-hanjun.guo@linaro.org> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Hanjun Guo Cc: Catalin Marinas , "Rafael J. Wysocki" , Mark Rutland , Mark Brown , Liviu Dudau , Lv Zheng , Lorenzo Pieralisi , Daniel Lezcano , Robert Moore , linux-acpi@vger.kernel.org, Grant Likely , Charles.Garcia-Tobin@arm.com, Robert Richter , Jason Cooper , Arnd Bergmann , Marc Zyngier , Will Deacon , Tomasz Nowicki , linaro-acpi-private@linaro.org, Bjorn Helgaas , linux-arm-kernel@lists.infradead.org, Graeme Gregory , Randy Dunlap , linux-kernel@vger.ke Hi Hanjun, On Thu, 2014-07-24 at 21:00 +0800, 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(-) > > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index 5ce85f8..6240327 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -14,6 +14,27 @@ > > /* Basic configuration for ACPI */ > #ifdef CONFIG_ACPI ^^ This seems to be a tab (\t) character here, which is a strange thing for me to see... > +/* > + * ACPI 5.1 only has two explicit methods to > + * boot up SMP, PSCI and Parking protocol, > + * but the Parking protocol is only defined > + * 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. > + * > + * This enum is intend to make the boot method > + * scalable when above updates are happended, > + * which NOT means to support all of them. > + */ This comment will become out of date soon (I hope), and it is often the case that these short term comments are not removed, so I think it better to put this kind of note into the commit message, not the code. > +enum acpi_smp_boot_protocol { > + ACPI_SMP_BOOT_PSCI, > + ACPI_SMP_BOOT_PARKING_PROTOCOL, > + ACPI_SMP_BOOT_PROTOCOL_MAX > +}; > + > +enum acpi_smp_boot_protocol smp_boot_protocol(void); > + > extern int acpi_disabled; > extern int acpi_noirq; > extern int acpi_pci_disabled; > diff --git a/arch/arm64/include/asm/cpu_ops.h b/arch/arm64/include/asm/cpu_ops.h > index d7b4b38..2a7c6fd 100644 > --- a/arch/arm64/include/asm/cpu_ops.h > +++ b/arch/arm64/include/asm/cpu_ops.h > @@ -61,7 +61,14 @@ struct cpu_operations { > }; > > extern const struct cpu_operations *cpu_ops[NR_CPUS]; > -extern int __init cpu_read_ops(struct device_node *dn, int cpu); > +extern int __init cpu_of_read_ops(struct device_node *dn, int cpu); > + > +#ifdef CONFIG_ACPI > +extern int __init cpu_acpi_read_ops(int cpu); > +#else > +static inline int __init cpu_acpi_read_ops(int cpu) { return -ENODEV; } > +#endif This looks messy and not scalable for new enable methods. It seems a better way is to retain cpu_read_ops() and its functionality, which is to return the proper enable method for that cpu in a generic way. Is there some reason you can't integrate acpi into the existing cpu_ops and need to make this completely parallel method? > extern void __init cpu_read_bootcpu_ops(void); > > #endif /* ifndef __ASM_CPU_OPS_H */ > diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h > index a498f2c..a5cea56 100644 > --- a/arch/arm64/include/asm/smp.h > +++ b/arch/arm64/include/asm/smp.h > @@ -39,7 +39,7 @@ 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) > + * Platform specific SMP operations > */ > extern void smp_init_cpus(void); > > 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 > > 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. > + */ Again, this comment will get old fast (I hope). > + 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; > + } > + > + return 0; > +} > +#endif > + > void __init cpu_read_bootcpu_ops(void) > { > - struct device_node *dn = of_get_cpu_node(0, NULL); > + struct device_node *dn; > + > + if (!acpi_disabled) { > + cpu_acpi_read_ops(0); > + return; > + } > + > + dn = of_get_cpu_node(0, NULL); > if (!dn) { > pr_err("Failed to find device node for boot cpu\n"); > return; > } > - cpu_read_ops(dn, 0); > + cpu_of_read_ops(dn, 0); > } > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > index 8f1d37c..cb71662 100644 > --- a/arch/arm64/kernel/smp.c > +++ b/arch/arm64/kernel/smp.c > @@ -315,7 +315,7 @@ static void (*smp_cross_call)(const struct cpumask *, unsigned int); > * 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) > +static void __init of_smp_init_cpus(void) > { > struct device_node *dn = NULL; > unsigned int i, cpu = 1; > @@ -387,7 +387,7 @@ void __init smp_init_cpus(void) > if (cpu >= NR_CPUS) > goto next; > > - if (cpu_read_ops(dn, cpu) != 0) > + if (cpu_of_read_ops(dn, cpu) != 0) > goto next; > > if (cpu_ops[cpu]->cpu_init(dn, cpu)) > @@ -418,6 +418,31 @@ next: > set_cpu_possible(i, true); > } > > +/* > + * In ACPI mode, the cpu possible map was enumerated before SMP > + * initialization when MADT table was parsed, so we can get the > + * possible map here to initialize CPUs. > + */ > +static void __init acpi_smp_init_cpus(void) > +{ > + int cpu; > + > + for_each_possible_cpu(cpu) { > + if (cpu_acpi_read_ops(cpu) != 0) > + continue; > + > + cpu_ops[cpu]->cpu_init(NULL, cpu); > + } > +} > + > +void __init smp_init_cpus(void) > +{ > + if (acpi_disabled) > + of_smp_init_cpus(); > + else > + acpi_smp_init_cpus(); > +} This is the same as cpu_ops, is acpi so special we need a completely parallel method of initializing secondary cpus? -Geoff From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752412AbaGaSwP (ORCPT ); Thu, 31 Jul 2014 14:52:15 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:41704 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952AbaGaSwN (ORCPT ); Thu, 31 Jul 2014 14:52:13 -0400 Message-ID: <1406832724.8971.29.camel@smoke> Subject: Re: [PATCH 10/19] ARM64 / ACPI: Get the enable method for SMP initialization in ACPI way From: Geoff Levand To: Hanjun Guo Cc: Catalin Marinas , "Rafael J. Wysocki" , Mark Rutland , Mark Brown , Liviu Dudau , Lv Zheng , Lorenzo Pieralisi , Daniel Lezcano , Robert Moore , linux-acpi@vger.kernel.org, Grant Likely , Charles.Garcia-Tobin@arm.com, Robert Richter , Jason Cooper , Arnd Bergmann , Marc Zyngier , Will Deacon , Tomasz Nowicki , linaro-acpi-private@linaro.org, Bjorn Helgaas , linux-arm-kernel@lists.infradead.org, Graeme Gregory , Randy Dunlap , linux-kernel@vger.kernel.org, Sudeep Holla Date: Thu, 31 Jul 2014 11:52:04 -0700 In-Reply-To: <1406206825-15590-11-git-send-email-hanjun.guo@linaro.org> References: <1406206825-15590-1-git-send-email-hanjun.guo@linaro.org> <1406206825-15590-11-git-send-email-hanjun.guo@linaro.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Hanjun, On Thu, 2014-07-24 at 21:00 +0800, 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(-) > > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index 5ce85f8..6240327 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -14,6 +14,27 @@ > > /* Basic configuration for ACPI */ > #ifdef CONFIG_ACPI ^^ This seems to be a tab (\t) character here, which is a strange thing for me to see... > +/* > + * ACPI 5.1 only has two explicit methods to > + * boot up SMP, PSCI and Parking protocol, > + * but the Parking protocol is only defined > + * 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. > + * > + * This enum is intend to make the boot method > + * scalable when above updates are happended, > + * which NOT means to support all of them. > + */ This comment will become out of date soon (I hope), and it is often the case that these short term comments are not removed, so I think it better to put this kind of note into the commit message, not the code. > +enum acpi_smp_boot_protocol { > + ACPI_SMP_BOOT_PSCI, > + ACPI_SMP_BOOT_PARKING_PROTOCOL, > + ACPI_SMP_BOOT_PROTOCOL_MAX > +}; > + > +enum acpi_smp_boot_protocol smp_boot_protocol(void); > + > extern int acpi_disabled; > extern int acpi_noirq; > extern int acpi_pci_disabled; > diff --git a/arch/arm64/include/asm/cpu_ops.h b/arch/arm64/include/asm/cpu_ops.h > index d7b4b38..2a7c6fd 100644 > --- a/arch/arm64/include/asm/cpu_ops.h > +++ b/arch/arm64/include/asm/cpu_ops.h > @@ -61,7 +61,14 @@ struct cpu_operations { > }; > > extern const struct cpu_operations *cpu_ops[NR_CPUS]; > -extern int __init cpu_read_ops(struct device_node *dn, int cpu); > +extern int __init cpu_of_read_ops(struct device_node *dn, int cpu); > + > +#ifdef CONFIG_ACPI > +extern int __init cpu_acpi_read_ops(int cpu); > +#else > +static inline int __init cpu_acpi_read_ops(int cpu) { return -ENODEV; } > +#endif This looks messy and not scalable for new enable methods. It seems a better way is to retain cpu_read_ops() and its functionality, which is to return the proper enable method for that cpu in a generic way. Is there some reason you can't integrate acpi into the existing cpu_ops and need to make this completely parallel method? > extern void __init cpu_read_bootcpu_ops(void); > > #endif /* ifndef __ASM_CPU_OPS_H */ > diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h > index a498f2c..a5cea56 100644 > --- a/arch/arm64/include/asm/smp.h > +++ b/arch/arm64/include/asm/smp.h > @@ -39,7 +39,7 @@ 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) > + * Platform specific SMP operations > */ > extern void smp_init_cpus(void); > > 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 > > 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. > + */ Again, this comment will get old fast (I hope). > + 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; > + } > + > + return 0; > +} > +#endif > + > void __init cpu_read_bootcpu_ops(void) > { > - struct device_node *dn = of_get_cpu_node(0, NULL); > + struct device_node *dn; > + > + if (!acpi_disabled) { > + cpu_acpi_read_ops(0); > + return; > + } > + > + dn = of_get_cpu_node(0, NULL); > if (!dn) { > pr_err("Failed to find device node for boot cpu\n"); > return; > } > - cpu_read_ops(dn, 0); > + cpu_of_read_ops(dn, 0); > } > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > index 8f1d37c..cb71662 100644 > --- a/arch/arm64/kernel/smp.c > +++ b/arch/arm64/kernel/smp.c > @@ -315,7 +315,7 @@ static void (*smp_cross_call)(const struct cpumask *, unsigned int); > * 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) > +static void __init of_smp_init_cpus(void) > { > struct device_node *dn = NULL; > unsigned int i, cpu = 1; > @@ -387,7 +387,7 @@ void __init smp_init_cpus(void) > if (cpu >= NR_CPUS) > goto next; > > - if (cpu_read_ops(dn, cpu) != 0) > + if (cpu_of_read_ops(dn, cpu) != 0) > goto next; > > if (cpu_ops[cpu]->cpu_init(dn, cpu)) > @@ -418,6 +418,31 @@ next: > set_cpu_possible(i, true); > } > > +/* > + * In ACPI mode, the cpu possible map was enumerated before SMP > + * initialization when MADT table was parsed, so we can get the > + * possible map here to initialize CPUs. > + */ > +static void __init acpi_smp_init_cpus(void) > +{ > + int cpu; > + > + for_each_possible_cpu(cpu) { > + if (cpu_acpi_read_ops(cpu) != 0) > + continue; > + > + cpu_ops[cpu]->cpu_init(NULL, cpu); > + } > +} > + > +void __init smp_init_cpus(void) > +{ > + if (acpi_disabled) > + of_smp_init_cpus(); > + else > + acpi_smp_init_cpus(); > +} This is the same as cpu_ops, is acpi so special we need a completely parallel method of initializing secondary cpus? -Geoff From mboxrd@z Thu Jan 1 00:00:00 1970 From: geoff@infradead.org (Geoff Levand) Date: Thu, 31 Jul 2014 11:52:04 -0700 Subject: [PATCH 10/19] ARM64 / ACPI: Get the enable method for SMP initialization in ACPI way In-Reply-To: <1406206825-15590-11-git-send-email-hanjun.guo@linaro.org> References: <1406206825-15590-1-git-send-email-hanjun.guo@linaro.org> <1406206825-15590-11-git-send-email-hanjun.guo@linaro.org> Message-ID: <1406832724.8971.29.camel@smoke> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Hanjun, On Thu, 2014-07-24 at 21:00 +0800, 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(-) > > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index 5ce85f8..6240327 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -14,6 +14,27 @@ > > /* Basic configuration for ACPI */ > #ifdef CONFIG_ACPI ^^ This seems to be a tab (\t) character here, which is a strange thing for me to see... > +/* > + * ACPI 5.1 only has two explicit methods to > + * boot up SMP, PSCI and Parking protocol, > + * but the Parking protocol is only defined > + * 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. > + * > + * This enum is intend to make the boot method > + * scalable when above updates are happended, > + * which NOT means to support all of them. > + */ This comment will become out of date soon (I hope), and it is often the case that these short term comments are not removed, so I think it better to put this kind of note into the commit message, not the code. > +enum acpi_smp_boot_protocol { > + ACPI_SMP_BOOT_PSCI, > + ACPI_SMP_BOOT_PARKING_PROTOCOL, > + ACPI_SMP_BOOT_PROTOCOL_MAX > +}; > + > +enum acpi_smp_boot_protocol smp_boot_protocol(void); > + > extern int acpi_disabled; > extern int acpi_noirq; > extern int acpi_pci_disabled; > diff --git a/arch/arm64/include/asm/cpu_ops.h b/arch/arm64/include/asm/cpu_ops.h > index d7b4b38..2a7c6fd 100644 > --- a/arch/arm64/include/asm/cpu_ops.h > +++ b/arch/arm64/include/asm/cpu_ops.h > @@ -61,7 +61,14 @@ struct cpu_operations { > }; > > extern const struct cpu_operations *cpu_ops[NR_CPUS]; > -extern int __init cpu_read_ops(struct device_node *dn, int cpu); > +extern int __init cpu_of_read_ops(struct device_node *dn, int cpu); > + > +#ifdef CONFIG_ACPI > +extern int __init cpu_acpi_read_ops(int cpu); > +#else > +static inline int __init cpu_acpi_read_ops(int cpu) { return -ENODEV; } > +#endif This looks messy and not scalable for new enable methods. It seems a better way is to retain cpu_read_ops() and its functionality, which is to return the proper enable method for that cpu in a generic way. Is there some reason you can't integrate acpi into the existing cpu_ops and need to make this completely parallel method? > extern void __init cpu_read_bootcpu_ops(void); > > #endif /* ifndef __ASM_CPU_OPS_H */ > diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h > index a498f2c..a5cea56 100644 > --- a/arch/arm64/include/asm/smp.h > +++ b/arch/arm64/include/asm/smp.h > @@ -39,7 +39,7 @@ 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) > + * Platform specific SMP operations > */ > extern void smp_init_cpus(void); > > 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 > > 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. > + */ Again, this comment will get old fast (I hope). > + 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; > + } > + > + return 0; > +} > +#endif > + > void __init cpu_read_bootcpu_ops(void) > { > - struct device_node *dn = of_get_cpu_node(0, NULL); > + struct device_node *dn; > + > + if (!acpi_disabled) { > + cpu_acpi_read_ops(0); > + return; > + } > + > + dn = of_get_cpu_node(0, NULL); > if (!dn) { > pr_err("Failed to find device node for boot cpu\n"); > return; > } > - cpu_read_ops(dn, 0); > + cpu_of_read_ops(dn, 0); > } > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > index 8f1d37c..cb71662 100644 > --- a/arch/arm64/kernel/smp.c > +++ b/arch/arm64/kernel/smp.c > @@ -315,7 +315,7 @@ static void (*smp_cross_call)(const struct cpumask *, unsigned int); > * 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) > +static void __init of_smp_init_cpus(void) > { > struct device_node *dn = NULL; > unsigned int i, cpu = 1; > @@ -387,7 +387,7 @@ void __init smp_init_cpus(void) > if (cpu >= NR_CPUS) > goto next; > > - if (cpu_read_ops(dn, cpu) != 0) > + if (cpu_of_read_ops(dn, cpu) != 0) > goto next; > > if (cpu_ops[cpu]->cpu_init(dn, cpu)) > @@ -418,6 +418,31 @@ next: > set_cpu_possible(i, true); > } > > +/* > + * In ACPI mode, the cpu possible map was enumerated before SMP > + * initialization when MADT table was parsed, so we can get the > + * possible map here to initialize CPUs. > + */ > +static void __init acpi_smp_init_cpus(void) > +{ > + int cpu; > + > + for_each_possible_cpu(cpu) { > + if (cpu_acpi_read_ops(cpu) != 0) > + continue; > + > + cpu_ops[cpu]->cpu_init(NULL, cpu); > + } > +} > + > +void __init smp_init_cpus(void) > +{ > + if (acpi_disabled) > + of_smp_init_cpus(); > + else > + acpi_smp_init_cpus(); > +} This is the same as cpu_ops, is acpi so special we need a completely parallel method of initializing secondary cpus? -Geoff