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@xxxxxxxxxx>
---
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@xxxxxxxxxx>
+ *
+ * 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
--
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