Commit 36c5014e authored by Wyes Karny's avatar Wyes Karny Committed by Rafael J. Wysocki
Browse files

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



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: default avatarHuang Rui <ray.huang@amd.com>
Reviewed-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Tested-by: default avatarWyes Karny <wyes.karny@amd.com>
Signed-off-by: default avatarPerry Yuan <perry.yuan@amd.com>
Signed-off-by: default avatarWyes Karny <wyes.karny@amd.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent e22abc6b

drivers/cpufreq/amd-pstate.c

+29 −10
Original line number Diff line number Diff line
@@ -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;

	}
@@ -671,17 +682,25 @@ 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;

	size = strlen(str);

	mode_idx = get_mode_idx_from_str(str, size);



	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");

	} else if (!strcmp(str, "passive"))

		cppc_load = 1;



		return 0;

	}



	return -EINVAL;

}

early_param("amd_pstate", amd_pstate_param);



MODULE_AUTHOR("Huang Rui <ray.huang@amd.com>");

include/linux/amd-pstate.h

+17 −0
Original line number Diff line number Diff line
@@ -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 */