Commit 2ff4b59f authored by Kaushlendra Kumar's avatar Kaushlendra Kumar Committed by Len Brown
Browse files

tools/power x86_energy_perf_policy: Add Android MSR device support 



Add support for Android MSR device paths which use /dev/msrN format
instead of the standard Linux /dev/cpu/N/msr format. The tool now
probes both path formats at startup and uses the appropriate one.

This enables x86_energy_perf_policy to work on Android systems where
MSR devices follow a different naming convention while maintaining
full compatibility with standard Linux systems.

Signed-off-by: default avatarKaushlendra Kumar <kaushlendra.kumar@intel.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent d71cb404

tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c

+46 −8
Original line number Diff line number Diff line
@@ -95,6 +95,9 @@ unsigned int bdx_highest_ratio; 
#define PATH_TO_CPU "/sys/devices/system/cpu/"

#define SYSFS_PATH_MAX 255



/* keep Default as a linux path */

static int use_android_msr_path;



/*

 * maintain compatibility with original implementation, but don't document it:

 */
@@ -678,16 +681,41 @@ void err_on_hypervisor(void) 
		    "not supported on this virtual machine");

}



static void probe_msr_path_format(void)

{

	struct stat sb;

	char test_path[32];



	/* Test standard Linux path */

	sprintf(test_path, "/dev/cpu/%d/msr", base_cpu);

	if (stat(test_path, &sb) == 0) {

		use_android_msr_path = 0;

		return;

	}



	/* Test Android-style path */

	sprintf(test_path, "/dev/msr%d", base_cpu);

	if (stat(test_path, &sb) == 0) {

		use_android_msr_path = 1;

		return;

	}



	/* If neither exists, keep the default Linux format */

	use_android_msr_path = 0;

}



int get_msr(int cpu, int offset, unsigned long long *msr)

{

	int retval;

	char pathname[32];

	int fd;



	sprintf(pathname, "/dev/cpu/%d/msr", cpu);

	sprintf(pathname, use_android_msr_path ? "/dev/msr%d" : "/dev/cpu/%d/msr", cpu);

	fd = open(pathname, O_RDONLY);

	if (fd < 0)

		err(-1, "%s open failed, try chown or chmod +r /dev/cpu/*/msr, or run as root", pathname);

		err(-1, "%s open failed, try chown or chmod +r %s, or run as root",

		   pathname, use_android_msr_path ? "/dev/msr*" : "/dev/cpu/*/msr");





	retval = pread(fd, msr, sizeof(*msr), offset);

	if (retval != sizeof(*msr)) {
@@ -708,10 +736,11 @@ int put_msr(int cpu, int offset, unsigned long long new_msr) 
	int retval;

	int fd;



	sprintf(pathname, "/dev/cpu/%d/msr", cpu);

	sprintf(pathname, use_android_msr_path ? "/dev/msr%d" : "/dev/cpu/%d/msr", cpu);

	fd = open(pathname, O_RDWR);

	if (fd < 0)

		err(-1, "%s open failed, try chown or chmod +r /dev/cpu/*/msr, or run as root", pathname);

		err(-1, "%s open failed, try chown or chmod +r %s, or run as root",

		   pathname, use_android_msr_path ? "/dev/msr*" : "/dev/cpu/*/msr");



	retval = pwrite(fd, &new_msr, sizeof(new_msr), offset);

	if (retval != sizeof(new_msr))
@@ -1427,11 +1456,16 @@ void probe_dev_msr(void) 
	struct stat sb;

	char pathname[32];



	sprintf(pathname, "/dev/cpu/%d/msr", base_cpu);

	if (stat(pathname, &sb))

		if (system("/sbin/modprobe msr > /dev/null 2>&1"))

	sprintf(pathname, use_android_msr_path ? "/dev/msr%d" : "/dev/cpu/%d/msr", base_cpu);

	if (stat(pathname, &sb)) {

		if (system("/sbin/modprobe msr > /dev/null 2>&1")) {

			if (use_android_msr_path)

				err(-5, "no /dev/msr0, Try \"# modprobe msr\" ");

			else

				err(-5, "no /dev/cpu/0/msr, Try \"# modprobe msr\" ");

		}

	}

}



static void get_cpuid_or_exit(unsigned int leaf,

			     unsigned int *eax, unsigned int *ebx,
@@ -1547,6 +1581,10 @@ void parse_cpuid(void) 
int main(int argc, char **argv)

{

	set_base_cpu();



	/* probe MSR path */

	probe_msr_path_format();



	probe_dev_msr();

	init_data_structures();