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cpufreq: amd-pstate: optimize driver working mode selection in amd_pstate_param()

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The amd-pstate driver may support multiple working modes.
Introduce a variable to keep track of which mode is currently enabled.
Here we use cppc_state var to indicate which mode is enabled.
This change will help to simplify the the amd_pstate_param() to choose
which mode used for the following driver registration.

Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Wyes Karny 2023-01-31 17:00:08 +08:00 committed by Rafael J. Wysocki
parent e22abc6bb9
commit 36c5014e54
2 changed files with 46 additions and 10 deletions
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39
drivers/cpufreq/amd-pstate.c
View file

@ -60,7 +60,18 @@
* module parameter to be able to enable it manually for debugging.
*/
static struct cpufreq_driver amd_pstate_driver;
static int cppc_load __initdata;
static int cppc_state = AMD_PSTATE_DISABLE;
static inline int get_mode_idx_from_str(const char *str, size_t size)
{
int i;
for (i=0; i < AMD_PSTATE_MAX; i++) {
if (!strncmp(str, amd_pstate_mode_string[i], size))
return i;
}
return -EINVAL;
}
static inline int pstate_enable(bool enable)
{
@ -626,10 +637,10 @@ static int __init amd_pstate_init(void)
/*
* by default the pstate driver is disabled to load
* enable the amd_pstate passive mode driver explicitly
* with amd_pstate=passive in kernel command line
* with amd_pstate=passive or other modes in kernel command line
*/
if (!cppc_load) {
pr_debug("driver load is disabled, boot with amd_pstate=passive to enable this\n");
if (cppc_state == AMD_PSTATE_DISABLE) {
pr_debug("driver load is disabled, boot with specific mode to enable this\n");
return -ENODEV;
}
@ -671,16 +682,24 @@ device_initcall(amd_pstate_init);
static int __init amd_pstate_param(char *str)
{
size_t size;
int mode_idx;
if (!str)
return -EINVAL;
if (!strcmp(str, "disable")) {
cppc_load = 0;
pr_info("driver is explicitly disabled\n");
} else if (!strcmp(str, "passive"))
cppc_load = 1;
size = strlen(str);
mode_idx = get_mode_idx_from_str(str, size);
return 0;
if (mode_idx >= AMD_PSTATE_DISABLE && mode_idx < AMD_PSTATE_MAX) {
cppc_state = mode_idx;
if (cppc_state == AMD_PSTATE_DISABLE)
pr_info("driver is explicitly disabled\n");
return 0;
}
return -EINVAL;
}
early_param("amd_pstate", amd_pstate_param);

17
include/linux/amd-pstate.h
View file

@ -74,4 +74,21 @@ struct amd_cpudata {
bool boost_supported;
};
/*
* enum amd_pstate_mode - driver working mode of amd pstate
*/
enum amd_pstate_mode {
AMD_PSTATE_DISABLE = 0,
AMD_PSTATE_PASSIVE,
AMD_PSTATE_ACTIVE,
AMD_PSTATE_MAX,
};
static const char * const amd_pstate_mode_string[] = {
[AMD_PSTATE_DISABLE] = "disable",
[AMD_PSTATE_PASSIVE] = "passive",
[AMD_PSTATE_ACTIVE] = "active",
NULL,
};
#endif /* _LINUX_AMD_PSTATE_H */