tools/power/turbostat: Cache graphics sysfs path

Graphics drivers (i915/Xe) have different sysfs knobs on different
platforms, and it is possible that different sysfs knobs fit into the
same turbostat columns.

Instead of specifying different sysfs knobs every time, detect them
once and cache the path for future use.

No functional change.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Author: zhang-rui

tools/power/x86/turbostat/turbostat.c

@@ -276,6 +276,19 @@ bool no_msr;
 bool no_perf;
 enum amperf_source amperf_source;
 
+enum gfx_sysfs_idx {
+	GFX_rc6,
+	GFX_MHz,
+	GFX_ACTMHz,
+	GFX_MAX
+};
+
+struct gfx_sysfs_info {
+	const char *path;
+};
+
+static struct gfx_sysfs_info gfx_info[GFX_MAX];
+
 int get_msr(int cpu, off_t offset, unsigned long long *msr);
 
 /* Model specific support Start */
@@ -4620,7 +4633,7 @@ int snapshot_gfx_rc6_ms(void)
 	FILE *fp;
 	int retval;
 
-	fp = fopen_or_die("/sys/class/drm/card0/power/rc6_residency_ms", "r");
+	fp = fopen_or_die(gfx_info[GFX_rc6].path, "r");
 
 	retval = fscanf(fp, "%lld", &gfx_cur_rc6_ms);
 	if (retval != 1)
@@ -4645,9 +4658,7 @@ int snapshot_gfx_mhz(void)
 	int retval;
 
 	if (fp == NULL) {
-		fp = fopen("/sys/class/drm/card0/gt_cur_freq_mhz", "r");
-		if (!fp)
-			fp = fopen_or_die("/sys/class/graphics/fb0/device/drm/card0/gt_cur_freq_mhz", "r");
+		fp = fopen_or_die(gfx_info[GFX_MHz].path, "r");
 	} else {
 		rewind(fp);
 		fflush(fp);
@@ -4674,9 +4685,7 @@ int snapshot_gfx_act_mhz(void)
 	int retval;
 
 	if (fp == NULL) {
-		fp = fopen("/sys/class/drm/card0/gt_act_freq_mhz", "r");
-		if (!fp)
-			fp = fopen_or_die("/sys/class/graphics/fb0/device/drm/card0/gt_act_freq_mhz", "r");
+		fp = fopen_or_die(gfx_info[GFX_ACTMHz].path, "r");
 	} else {
 		rewind(fp);
 		fflush(fp);
@@ -5338,14 +5347,24 @@ static void probe_intel_uncore_frequency(void)
 static void probe_graphics(void)
 {
 	if (!access("/sys/class/drm/card0/power/rc6_residency_ms", R_OK))
-		BIC_PRESENT(BIC_GFX_rc6);
+		gfx_info[GFX_rc6].path = "/sys/class/drm/card0/power/rc6_residency_ms";
 
-	if (!access("/sys/class/drm/card0/gt_cur_freq_mhz", R_OK) ||
-	    !access("/sys/class/graphics/fb0/device/drm/card0/gt_cur_freq_mhz", R_OK))
-		BIC_PRESENT(BIC_GFXMHz);
+	if (!access("/sys/class/drm/card0/gt_cur_freq_mhz", R_OK))
+		gfx_info[GFX_MHz].path = "/sys/class/drm/card0/gt_cur_freq_mhz";
+	else if (!access("/sys/class/graphics/fb0/device/drm/card0/gt_cur_freq_mhz", R_OK))
+		gfx_info[GFX_MHz].path = "/sys/class/graphics/fb0/device/drm/card0/gt_cur_freq_mhz";
+
+
+	if (!access("/sys/class/drm/card0/gt_act_freq_mhz", R_OK))
+		gfx_info[GFX_ACTMHz].path = "/sys/class/drm/card0/gt_act_freq_mhz";
+	else if (!access("/sys/class/graphics/fb0/device/drm/card0/gt_act_freq_mhz", R_OK))
+		gfx_info[GFX_ACTMHz].path = "/sys/class/graphics/fb0/device/drm/card0/gt_act_freq_mhz";
 
-	if (!access("/sys/class/drm/card0/gt_act_freq_mhz", R_OK) ||
-	    !access("/sys/class/graphics/fb0/device/drm/card0/gt_act_freq_mhz", R_OK))
+	if (gfx_info[GFX_rc6].path)
+		BIC_PRESENT(BIC_GFX_rc6);
+	if (gfx_info[GFX_MHz].path)
+		BIC_PRESENT(BIC_GFXMHz);
+	if (gfx_info[GFX_ACTMHz].path)
 		BIC_PRESENT(BIC_GFXACTMHz);
 }