cppc_set_epp - write energy performance preference register value, based on
ACPI 6.5, s8.4.6.1.7
cppc_get_auto_act_window - read autonomous activity window register value,
based on ACPI 6.5, s8.4.6.1.6
cppc_set_auto_act_window - write autonomous activity window register value,
based on ACPI 6.5, s8.4.6.1.6
Reviewed-by: Pierre Gondois <pierre.gondois@arm.com>
Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
---
drivers/acpi/cppc_acpi.c | 80 ++++++++++++++++++++++++++++++++++++++++
include/acpi/cppc_acpi.h | 24 ++++++++++++
2 files changed, 104 insertions(+)
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index ef2394c074e3..3d5eace44af5 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1608,6 +1608,86 @@ int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
}
EXPORT_SYMBOL_GPL(cppc_set_epp_perf);
+/**
+ * cppc_set_epp() - Write the EPP register.
+ * @cpu: CPU on which to write register.
+ * @epp_val: Value to write to the EPP register.
+ */
+int cppc_set_epp(int cpu, u64 epp_val)
+{
+ if (epp_val > CPPC_ENERGY_PERF_MAX)
+ return -EINVAL;
+
+ return cppc_set_reg_val(cpu, ENERGY_PERF, epp_val);
+}
+EXPORT_SYMBOL_GPL(cppc_set_epp);
+
+/**
+ * cppc_get_auto_act_window() - Read autonomous activity window register.
+ * @cpu: CPU from which to read register.
+ * @auto_act_window: Return address.
+ *
+ * According to ACPI 6.5, s8.4.6.1.6, the value read from the autonomous
+ * activity window register consists of two parts: a 7 bits value indicate
+ * significand and a 3 bits value indicate exponent.
+ */
+int cppc_get_auto_act_window(int cpu, u64 *auto_act_window)
+{
+ unsigned int exp;
+ u64 val, sig;
+ int ret;
+
+ ret = cppc_get_reg_val(cpu, AUTO_ACT_WINDOW, &val);
+ if (ret)
+ return ret;
+
+ sig = val & CPPC_AUTO_ACT_WINDOW_MAX_SIG;
+ exp = (val >> CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE) & CPPC_AUTO_ACT_WINDOW_MAX_EXP;
+ *auto_act_window = sig * int_pow(10, exp);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(cppc_get_auto_act_window);
+
+/**
+ * cppc_set_auto_act_window() - Write autonomous activity window register.
+ * @cpu: CPU on which to write register.
+ * @auto_act_window: usec value to write to the autonomous activity window register.
+ *
+ * According to ACPI 6.5, s8.4.6.1.6, the value to write to the autonomous
+ * activity window register consists of two parts: a 7 bits value indicate
+ * significand and a 3 bits value indicate exponent.
+ */
+int cppc_set_auto_act_window(int cpu, u64 auto_act_window)
+{
+ /* The max value to stroe is 1270000000 */
+ u64 max_val = CPPC_AUTO_ACT_WINDOW_MAX_SIG * int_pow(10, CPPC_AUTO_ACT_WINDOW_MAX_EXP);
+ int exp = 0;
+ u64 val;
+
+ if (auto_act_window > max_val)
+ return -EINVAL;
+
+ /*
+ * The max significand is 127, when auto_act_window is larger than
+ * 129, discard the precision of the last digit and increase the
+ * exponent by 1.
+ */
+ while (auto_act_window > CPPC_AUTO_ACT_WINDOW_SIG_CARRY_THRESH) {
+ auto_act_window /= 10;
+ exp += 1;
+ }
+
+ /* For 128 and 129, cut it to 127. */
+ if (auto_act_window > CPPC_AUTO_ACT_WINDOW_MAX_SIG)
+ auto_act_window = CPPC_AUTO_ACT_WINDOW_MAX_SIG;
+
+ val = (exp << CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE) + auto_act_window;
+
+ return cppc_set_reg_val(cpu, AUTO_ACT_WINDOW, val);
+}
+EXPORT_SYMBOL_GPL(cppc_set_auto_act_window);
+
/**
* cppc_get_auto_sel() - Read autonomous selection register.
* @cpu: CPU from which to read register.
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index 31767c65be20..325e9543e08f 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -32,6 +32,15 @@
#define CMD_READ 0
#define CMD_WRITE 1
+#define CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE (7)
+#define CPPC_AUTO_ACT_WINDOW_EXP_BIT_SIZE (3)
+#define CPPC_AUTO_ACT_WINDOW_MAX_SIG ((1 << CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE) - 1)
+#define CPPC_AUTO_ACT_WINDOW_MAX_EXP ((1 << CPPC_AUTO_ACT_WINDOW_EXP_BIT_SIZE) - 1)
+/* CPPC_AUTO_ACT_WINDOW_MAX_SIG is 127, so 128 and 129 will decay to 127 when writing */
+#define CPPC_AUTO_ACT_WINDOW_SIG_CARRY_THRESH 129
+
+#define CPPC_ENERGY_PERF_MAX (0xFF)
+
/* Each register has the folowing format. */
struct cpc_reg {
u8 descriptor;
@@ -159,6 +168,9 @@ extern int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val);
extern int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val);
extern int cppc_get_epp_perf(int cpunum, u64 *epp_perf);
extern int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable);
+extern int cppc_set_epp(int cpu, u64 epp_val);
+extern int cppc_get_auto_act_window(int cpu, u64 *auto_act_window);
+extern int cppc_set_auto_act_window(int cpu, u64 auto_act_window);
extern int cppc_get_auto_sel(int cpu, bool *enable);
extern int cppc_set_auto_sel(int cpu, bool enable);
extern int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf);
@@ -229,6 +241,18 @@ static inline int cppc_get_epp_perf(int cpunum, u64 *epp_perf)
{
return -EOPNOTSUPP;
}
+static inline int cppc_set_epp(int cpu, u64 epp_val)
+{
+ return -EOPNOTSUPP;
+}
+static inline int cppc_get_auto_act_window(int cpu, u64 *auto_act_window)
+{
+ return -EOPNOTSUPP;
+}
+static inline int cppc_set_auto_act_window(int cpu, u64 auto_act_window)
+{
+ return -EOPNOTSUPP;
+}
static inline int cppc_get_auto_sel(int cpu, bool *enable)
{
return -EOPNOTSUPP;
--
2.33.0On 4/9/2025 1:57 AM, Lifeng Zheng wrote:
> cppc_set_epp - write energy performance preference register value, based on
> ACPI 6.5, s8.4.6.1.7
>
> cppc_get_auto_act_window - read autonomous activity window register value,
> based on ACPI 6.5, s8.4.6.1.6
>
> cppc_set_auto_act_window - write autonomous activity window register value,
> based on ACPI 6.5, s8.4.6.1.6
>
> Reviewed-by: Pierre Gondois <pierre.gondois@arm.com>
> Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
> ---
> drivers/acpi/cppc_acpi.c | 80 ++++++++++++++++++++++++++++++++++++++++
> include/acpi/cppc_acpi.h | 24 ++++++++++++
> 2 files changed, 104 insertions(+)
>
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index ef2394c074e3..3d5eace44af5 100644
> --- a/drivers/acpi/cppc_acpi.c
> +++ b/drivers/acpi/cppc_acpi.c
> @@ -1608,6 +1608,86 @@ int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
> }
> EXPORT_SYMBOL_GPL(cppc_set_epp_perf);
>
> +/**
> + * cppc_set_epp() - Write the EPP register.
> + * @cpu: CPU on which to write register.
> + * @epp_val: Value to write to the EPP register.
> + */
> +int cppc_set_epp(int cpu, u64 epp_val)
Any reason this is a u64 argument when the biggest value you can support
is 0xFF? Presumably you could drop the the bounds check below if you
limited the variable size.
> +{
> + if (epp_val > CPPC_ENERGY_PERF_MAX)
> + return -EINVAL;
> +
> + return cppc_set_reg_val(cpu, ENERGY_PERF, epp_val);
> +}
> +EXPORT_SYMBOL_GPL(cppc_set_epp);
> +
> +/**
> + * cppc_get_auto_act_window() - Read autonomous activity window register.
> + * @cpu: CPU from which to read register.
> + * @auto_act_window: Return address.
> + *
> + * According to ACPI 6.5, s8.4.6.1.6, the value read from the autonomous
> + * activity window register consists of two parts: a 7 bits value indicate
> + * significand and a 3 bits value indicate exponent.
> + */
> +int cppc_get_auto_act_window(int cpu, u64 *auto_act_window)
> +{
> + unsigned int exp;
> + u64 val, sig;
> + int ret;
> +
> + ret = cppc_get_reg_val(cpu, AUTO_ACT_WINDOW, &val);
> + if (ret)
> + return ret;
> +
> + sig = val & CPPC_AUTO_ACT_WINDOW_MAX_SIG;
> + exp = (val >> CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE) & CPPC_AUTO_ACT_WINDOW_MAX_EXP;
> + *auto_act_window = sig * int_pow(10, exp);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(cppc_get_auto_act_window);
Since this is exported code, do you perhaps want a check that
auto_act_window is not NULL to avoid a possible accidental NULL pointer
dereference?
> +
> +/**
> + * cppc_set_auto_act_window() - Write autonomous activity window register.
> + * @cpu: CPU on which to write register.
> + * @auto_act_window: usec value to write to the autonomous activity window register.
> + *
> + * According to ACPI 6.5, s8.4.6.1.6, the value to write to the autonomous
> + * activity window register consists of two parts: a 7 bits value indicate
> + * significand and a 3 bits value indicate exponent.
> + */
> +int cppc_set_auto_act_window(int cpu, u64 auto_act_window)
> +{
> + /* The max value to stroe is 1270000000 */
store
> + u64 max_val = CPPC_AUTO_ACT_WINDOW_MAX_SIG * int_pow(10, CPPC_AUTO_ACT_WINDOW_MAX_EXP);
> + int exp = 0;
> + u64 val;
> +
> + if (auto_act_window > max_val)
> + return -EINVAL;
> +
> + /*
> + * The max significand is 127, when auto_act_window is larger than
> + * 129, discard the precision of the last digit and increase the
> + * exponent by 1.
> + */
> + while (auto_act_window > CPPC_AUTO_ACT_WINDOW_SIG_CARRY_THRESH) {
> + auto_act_window /= 10;
> + exp += 1;
> + }
> +
> + /* For 128 and 129, cut it to 127. */
> + if (auto_act_window > CPPC_AUTO_ACT_WINDOW_MAX_SIG)
> + auto_act_window = CPPC_AUTO_ACT_WINDOW_MAX_SIG;
> +
> + val = (exp << CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE) + auto_act_window;
> +
> + return cppc_set_reg_val(cpu, AUTO_ACT_WINDOW, val);
> +}
> +EXPORT_SYMBOL_GPL(cppc_set_auto_act_window);
> +
> /**
> * cppc_get_auto_sel() - Read autonomous selection register.
> * @cpu: CPU from which to read register.
> diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
> index 31767c65be20..325e9543e08f 100644
> --- a/include/acpi/cppc_acpi.h
> +++ b/include/acpi/cppc_acpi.h
> @@ -32,6 +32,15 @@
> #define CMD_READ 0
> #define CMD_WRITE 1
>
> +#define CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE (7)
> +#define CPPC_AUTO_ACT_WINDOW_EXP_BIT_SIZE (3)
> +#define CPPC_AUTO_ACT_WINDOW_MAX_SIG ((1 << CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE) - 1)
> +#define CPPC_AUTO_ACT_WINDOW_MAX_EXP ((1 << CPPC_AUTO_ACT_WINDOW_EXP_BIT_SIZE) - 1)
> +/* CPPC_AUTO_ACT_WINDOW_MAX_SIG is 127, so 128 and 129 will decay to 127 when writing */
> +#define CPPC_AUTO_ACT_WINDOW_SIG_CARRY_THRESH 129
> +
> +#define CPPC_ENERGY_PERF_MAX (0xFF)
> +
> /* Each register has the folowing format. */
> struct cpc_reg {
> u8 descriptor;
> @@ -159,6 +168,9 @@ extern int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val);
> extern int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val);
> extern int cppc_get_epp_perf(int cpunum, u64 *epp_perf);
> extern int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable);
> +extern int cppc_set_epp(int cpu, u64 epp_val);
> +extern int cppc_get_auto_act_window(int cpu, u64 *auto_act_window);
> +extern int cppc_set_auto_act_window(int cpu, u64 auto_act_window);
> extern int cppc_get_auto_sel(int cpu, bool *enable);
> extern int cppc_set_auto_sel(int cpu, bool enable);
> extern int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf);
> @@ -229,6 +241,18 @@ static inline int cppc_get_epp_perf(int cpunum, u64 *epp_perf)
> {
> return -EOPNOTSUPP;
> }
> +static inline int cppc_set_epp(int cpu, u64 epp_val)
> +{
> + return -EOPNOTSUPP;
> +}
> +static inline int cppc_get_auto_act_window(int cpu, u64 *auto_act_window)
> +{
> + return -EOPNOTSUPP;
> +}
> +static inline int cppc_set_auto_act_window(int cpu, u64 auto_act_window)
> +{
> + return -EOPNOTSUPP;
> +}
> static inline int cppc_get_auto_sel(int cpu, bool *enable)
> {
> return -EOPNOTSUPP;
On 2025/4/10 2:59, Mario Limonciello wrote:
> On 4/9/2025 1:57 AM, Lifeng Zheng wrote:
>> cppc_set_epp - write energy performance preference register value, based on
>> ACPI 6.5, s8.4.6.1.7
>>
>> cppc_get_auto_act_window - read autonomous activity window register value,
>> based on ACPI 6.5, s8.4.6.1.6
>>
>> cppc_set_auto_act_window - write autonomous activity window register value,
>> based on ACPI 6.5, s8.4.6.1.6
>>
>> Reviewed-by: Pierre Gondois <pierre.gondois@arm.com>
>> Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
>> ---
>> drivers/acpi/cppc_acpi.c | 80 ++++++++++++++++++++++++++++++++++++++++
>> include/acpi/cppc_acpi.h | 24 ++++++++++++
>> 2 files changed, 104 insertions(+)
>>
>> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
>> index ef2394c074e3..3d5eace44af5 100644
>> --- a/drivers/acpi/cppc_acpi.c
>> +++ b/drivers/acpi/cppc_acpi.c
>> @@ -1608,6 +1608,86 @@ int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
>> }
>> EXPORT_SYMBOL_GPL(cppc_set_epp_perf);
>> +/**
>> + * cppc_set_epp() - Write the EPP register.
>> + * @cpu: CPU on which to write register.
>> + * @epp_val: Value to write to the EPP register.
>> + */
>> +int cppc_set_epp(int cpu, u64 epp_val)
>
> Any reason this is a u64 argument when the biggest value you can support is 0xFF? Presumably you could drop the the bounds check below if you limited the variable size.
cppc_get_epp_perf() uses u64, so I think it is better to keep the same.
>
>> +{
>> + if (epp_val > CPPC_ENERGY_PERF_MAX)
>> + return -EINVAL;
>> +
>> + return cppc_set_reg_val(cpu, ENERGY_PERF, epp_val);
>> +}
>> +EXPORT_SYMBOL_GPL(cppc_set_epp);
>> +
>> +/**
>> + * cppc_get_auto_act_window() - Read autonomous activity window register.
>> + * @cpu: CPU from which to read register.
>> + * @auto_act_window: Return address.
>> + *
>> + * According to ACPI 6.5, s8.4.6.1.6, the value read from the autonomous
>> + * activity window register consists of two parts: a 7 bits value indicate
>> + * significand and a 3 bits value indicate exponent.
>> + */
>> +int cppc_get_auto_act_window(int cpu, u64 *auto_act_window)
>> +{
>> + unsigned int exp;
>> + u64 val, sig;
>> + int ret;
>> +
>> + ret = cppc_get_reg_val(cpu, AUTO_ACT_WINDOW, &val);
>> + if (ret)
>> + return ret;
>> +
>> + sig = val & CPPC_AUTO_ACT_WINDOW_MAX_SIG;
>> + exp = (val >> CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE) & CPPC_AUTO_ACT_WINDOW_MAX_EXP;
>> + *auto_act_window = sig * int_pow(10, exp);
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(cppc_get_auto_act_window);
>
> Since this is exported code, do you perhaps want a check that auto_act_window is not NULL to avoid a possible accidental NULL pointer dereference?
Yes. Make sense. Thanks!
>
>> +
>> +/**
>> + * cppc_set_auto_act_window() - Write autonomous activity window register.
>> + * @cpu: CPU on which to write register.
>> + * @auto_act_window: usec value to write to the autonomous activity window register.
>> + *
>> + * According to ACPI 6.5, s8.4.6.1.6, the value to write to the autonomous
>> + * activity window register consists of two parts: a 7 bits value indicate
>> + * significand and a 3 bits value indicate exponent.
>> + */
>> +int cppc_set_auto_act_window(int cpu, u64 auto_act_window)
>> +{
>> + /* The max value to stroe is 1270000000 */
>
> store
Thanks!
>
>> + u64 max_val = CPPC_AUTO_ACT_WINDOW_MAX_SIG * int_pow(10, CPPC_AUTO_ACT_WINDOW_MAX_EXP);
>> + int exp = 0;
>> + u64 val;
>> +
>> + if (auto_act_window > max_val)
>> + return -EINVAL;
>> +
>> + /*
>> + * The max significand is 127, when auto_act_window is larger than
>> + * 129, discard the precision of the last digit and increase the
>> + * exponent by 1.
>> + */
>> + while (auto_act_window > CPPC_AUTO_ACT_WINDOW_SIG_CARRY_THRESH) {
>> + auto_act_window /= 10;
>> + exp += 1;
>> + }
>> +
>> + /* For 128 and 129, cut it to 127. */
>> + if (auto_act_window > CPPC_AUTO_ACT_WINDOW_MAX_SIG)
>> + auto_act_window = CPPC_AUTO_ACT_WINDOW_MAX_SIG;
>> +
>> + val = (exp << CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE) + auto_act_window;
>> +
>> + return cppc_set_reg_val(cpu, AUTO_ACT_WINDOW, val);
>> +}
>> +EXPORT_SYMBOL_GPL(cppc_set_auto_act_window);
>> +
>> /**
>> * cppc_get_auto_sel() - Read autonomous selection register.
>> * @cpu: CPU from which to read register.
>> diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
>> index 31767c65be20..325e9543e08f 100644
>> --- a/include/acpi/cppc_acpi.h
>> +++ b/include/acpi/cppc_acpi.h
>> @@ -32,6 +32,15 @@
>> #define CMD_READ 0
>> #define CMD_WRITE 1
>> +#define CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE (7)
>> +#define CPPC_AUTO_ACT_WINDOW_EXP_BIT_SIZE (3)
>> +#define CPPC_AUTO_ACT_WINDOW_MAX_SIG ((1 << CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE) - 1)
>> +#define CPPC_AUTO_ACT_WINDOW_MAX_EXP ((1 << CPPC_AUTO_ACT_WINDOW_EXP_BIT_SIZE) - 1)
>> +/* CPPC_AUTO_ACT_WINDOW_MAX_SIG is 127, so 128 and 129 will decay to 127 when writing */
>> +#define CPPC_AUTO_ACT_WINDOW_SIG_CARRY_THRESH 129
>> +
>> +#define CPPC_ENERGY_PERF_MAX (0xFF)
>> +
>> /* Each register has the folowing format. */
>> struct cpc_reg {
>> u8 descriptor;
>> @@ -159,6 +168,9 @@ extern int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val);
>> extern int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val);
>> extern int cppc_get_epp_perf(int cpunum, u64 *epp_perf);
>> extern int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable);
>> +extern int cppc_set_epp(int cpu, u64 epp_val);
>> +extern int cppc_get_auto_act_window(int cpu, u64 *auto_act_window);
>> +extern int cppc_set_auto_act_window(int cpu, u64 auto_act_window);
>> extern int cppc_get_auto_sel(int cpu, bool *enable);
>> extern int cppc_set_auto_sel(int cpu, bool enable);
>> extern int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf);
>> @@ -229,6 +241,18 @@ static inline int cppc_get_epp_perf(int cpunum, u64 *epp_perf)
>> {
>> return -EOPNOTSUPP;
>> }
>> +static inline int cppc_set_epp(int cpu, u64 epp_val)
>> +{
>> + return -EOPNOTSUPP;
>> +}
>> +static inline int cppc_get_auto_act_window(int cpu, u64 *auto_act_window)
>> +{
>> + return -EOPNOTSUPP;
>> +}
>> +static inline int cppc_set_auto_act_window(int cpu, u64 auto_act_window)
>> +{
>> + return -EOPNOTSUPP;
>> +}
>> static inline int cppc_get_auto_sel(int cpu, bool *enable)
>> {
>> return -EOPNOTSUPP;
>
© 2016 - 2026 Red Hat, Inc.