Re: [Linaro-acpi] [RFC 3/3] CPPC: Add ACPI accessors to CPC registers

+ Rafael [corrected email addr]

On 14 August 2014 15:57, Ashwin Chaugule ashwin.chaugule@linaro.org wrote:

If the firmware supports CPPC natively in the firmware then we can use the ACPI defined semantics to access the CPPC specific registers.

Signed-off-by: Ashwin Chaugule ashwin.chaugule@linaro.org

drivers/cpufreq/Kconfig | 9 +++++ drivers/cpufreq/Makefile | 1 + drivers/cpufreq/cppc.h | 4 +-- drivers/cpufreq/cppc_acpi.c | 80 +++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 92 insertions(+), 2 deletions(-) create mode 100644 drivers/cpufreq/cppc_acpi.c

diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig index d8e8335..c5f3c0b 100644 --- a/drivers/cpufreq/Kconfig +++ b/drivers/cpufreq/Kconfig @@ -206,6 +206,15 @@ config CPPC_CPUFREQ (e.g. BMC) interpret and optimize it for power and performance in a platform specific manner.

+config CPPC_ACPI

•   bool "CPPC with ACPI accessors"
  

•   depends on ACPI && ACPI_PCC
  

•   default n
  

•   help
  

•   This driver implements the low level accessors to the registers as described
  

•   in the ACPI 5.1 spec. Select this driver if you know your platform supports CPPC
  

•   and PCC in the firmware.
  

menu "x86 CPU frequency scaling drivers" depends on X86 source "drivers/cpufreq/Kconfig.x86" diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index b392c8c..d49a999 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -15,6 +15,7 @@ obj-$(CONFIG_CPU_FREQ_GOV_COMMON) += cpufreq_governor.o

obj-$(CONFIG_GENERIC_CPUFREQ_CPU0) += cpufreq-cpu0.o obj-$(CONFIG_CPPC_CPUFREQ) += cppc.o +obj-$(CONFIG_CPPC_ACPI) += cppc_acpi.o

################################################################################## # x86 drivers. diff --git a/drivers/cpufreq/cppc.h b/drivers/cpufreq/cppc.h index 3adbd3d..a119c3b 100644 --- a/drivers/cpufreq/cppc.h +++ b/drivers/cpufreq/cppc.h @@ -175,7 +175,7 @@ struct cpc_funcs { };

extern struct cpc_funcs *cppc_func_ops; -extern u64 cpc_read64(struct cpc_register_resource *reg); -extern int cpc_write64(u64 val, struct cpc_register_resource *reg); +extern u64 cpc_read64(struct cpc_register_resource *reg, void __iomem *base_addr); +extern int cpc_write64(u64 val, struct cpc_register_resource *reg, void __iomem *base_addr);

#endif /* _CPPC_H */ diff --git a/drivers/cpufreq/cppc_acpi.c b/drivers/cpufreq/cppc_acpi.c new file mode 100644 index 0000000..1835fe7 --- /dev/null +++ b/drivers/cpufreq/cppc_acpi.c @@ -0,0 +1,80 @@ +/*

• • Copyright (C) 2014 Linaro Ltd.
    

• • Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
    

• • This program is free software; you can redistribute it and/or modify
• • it under the terms of the GNU General Public License as published by
• • the Free Software Foundation; either version 2 of the License, or
• • (at your option) any later version.
• • This program is distributed in the hope that it will be useful,
• • but WITHOUT ANY WARRANTY; without even the implied warranty of
• • MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
• • GNU General Public License for more details.
• */

+#include <linux/acpi.h>

+#include "cppc.h"

+static u32 acpi_get_highest_perf(struct cpudata *cpu) +{

•   struct cpc_register_resource *high_perf = &cpu->cpc_desc->cpc_regs[HIGHEST_PERF];
  

•   return cpc_read64(high_perf, cpu->pcc_comm_address);
  

+}

+static u64 acpi_get_ref_perf_ctr(struct cpudata *cpu) +{

•   struct cpc_register_resource *ref_perf = &cpu->cpc_desc->cpc_regs[REFERENCE_CTR];
  

•   return cpc_read64(ref_perf, cpu->pcc_comm_address);
  

+}

+static u32 acpi_get_lowest_perf(struct cpudata *cpu) +{

•   struct cpc_register_resource *low_perf = &cpu->cpc_desc->cpc_regs[LOWEST_PERF];
  

•   return cpc_read64(low_perf, cpu->pcc_comm_address);
  

+}

+static void acpi_set_desired_perf(struct cpudata *cpu, u32 val) +{

•   struct cpc_register_resource *desired_perf = &cpu->cpc_desc->cpc_regs[DESIRED_PERF];
  

•   cpc_write64(val, desired_perf, cpu->pcc_comm_address);
  

+}

+static u64 acpi_get_delivered_ctr(struct cpudata *cpu) +{

•   struct cpc_register_resource *delivered_ctr = &cpu->cpc_desc->cpc_regs[DELIVERED_CTR];
  

•   return cpc_read64(delivered_ctr, cpu->pcc_comm_address);
  

+}

+struct cpc_funcs acpi_cppc_func_ops = {

•   .pid_policy = {
  

•           .sample_rate_ms = 10,
  

•           .deadband = 0,
  

•           .setpoint = 97,
  

•           .p_gain_pct = 20,
  

•           .d_gain_pct = 0,
  

•           .i_gain_pct = 0,
  

•   },
  

•   .get_highest_perf       =       acpi_get_highest_perf,
  

•   .get_ref_perf_ctr       =       acpi_get_ref_perf_ctr,
  

•   .get_lowest_perf        =       acpi_get_lowest_perf,
  

•   .set_desired_perf       =       acpi_set_desired_perf,
  

•   .get_delivered_ctr      =       acpi_get_delivered_ctr,
  

+};

+static int __init acpi_cppc_init(void) +{

•   if (acpi_disabled)
  

•           return 0;
  

•   cppc_func_ops = &acpi_cppc_func_ops;
  

•   pr_info("Registered ACPI CPPC function ops\n");
  

•   return 0;
  

+} +early_initcall(acpi_cppc_init);

-- 1.9.1