cleanup linux cpuinfo code

sonynwz: quirk for cpufreq broken driver

There was some redundancy between frequency_linux(cpu, true) and
current_scaling_frequency(), also I see no reason to compile the cpuinfo stuff
unconditionally and the scaling info only on DX since it was already printed
some partial scaling info anyway. Thus compile all the code unconditionally
and simplify the logic in the debug menu. Also avoid putting buffers of size
PATH_MAX on stack since it can be quite big and we only requires 64 bytes
for those paths.

On Sony NWZ, the cpu driver reports frequency in MHz instead of kHz thus we need
to make the cpuinfo code aware of that bug.

Change-Id: I61af45ab5f179ecc909b4841b9137a915a60193a

3 files changed, 27 insertions, 29 deletions

diff --git a/apps/debug_menu.c b/apps/debug_menu.c
index 5224dbe267..4947f30695 100644
--- a/apps/debug_menu.c
+++ b/apps/debug_menu.c
@@ -240,9 +240,13 @@ static const char* get_cpuinfo(int selected_item, void *data,
         {
             int cpu = (selected_item - 5) / (state_count + 1);
             int cpu_line = (selected_item - 5) % (state_count + 1);
-#if defined(DX50) || defined(DX90)
+
+            /* scaling info */
             int min_freq = min_scaling_frequency(cpu);
             int cur_freq = current_scaling_frequency(cpu);
+            /* fallback if scaling frequency is not available */
+            if(cur_freq <= 0)
+                cur_freq = frequency_linux(cpu);
             int max_freq = max_scaling_frequency(cpu);
             char governor[20];
             bool have_governor = current_scaling_governor(cpu, governor, sizeof(governor));
@@ -256,16 +260,6 @@ static const char* get_cpuinfo(int selected_item, void *data,
                         cur_freq > 0 ? cur_freq/1000 : -1,
                         max_freq > 0 ? max_freq/1000 : -1);
             }
-#else
-            int freq1 = frequency_linux(cpu, false);
-            int freq2 = frequency_linux(cpu, true);
-            if (cpu_line == 0)
-            {
-                sprintf(buffer, " CPU%d: Cur/Scal freq: %d/%d MHz", cpu,
-                                freq1 > 0 ? freq1/1000 : -1,
-                                freq2 > 0 ? freq2/1000 : -1);
-            }
-#endif
             else
             {
                 cpustatetimes_linux(cpu, states, ARRAYLEN(states));
diff --git a/firmware/target/hosted/cpuinfo-linux.c b/firmware/target/hosted/cpuinfo-linux.c
index 8158673349..c3669a9f5c 100644
--- a/firmware/target/hosted/cpuinfo-linux.c
+++ b/firmware/target/hosted/cpuinfo-linux.c
@@ -35,11 +35,9 @@
 #include "cpuinfo-linux.h"
 #include "gcc_extensions.h"
 
-#if defined(DX50) || defined(DX90)
 #include <limits.h>
 #include <string.h>
 #include "debug.h"
-#endif
 
 #undef open /* want the *real* open here, not sim_open or the like */
 #if (CONFIG_PLATFORM & PLATFORM_ANDROID) || defined(DX50) || defined(DX90)
@@ -51,6 +49,14 @@
 #define NUM_SAMPLES_MASK (NUM_SAMPLES-1)
 #define SAMPLE_RATE  4
 
+/* Some targets like the Sony NWZ have a broken cpu driver that reports frequencies in MHz instead
+ * of kHz */
+#if defined(SONY_NWZ_LINUX)
+#define FREQ_MULTIPLIER     1000
+#else
+#define FREQ_MULTIPLIER     1
+#endif
+
 struct cputime_sample {
     struct tms sample;
     time_t time;
@@ -143,24 +149,21 @@ int cpucount_linux(void)
     return get_nprocs();
 }
 
-int frequency_linux(int cpu, bool scaling)
+int frequency_linux(int cpu)
 {
     char path[64];
     char temp[10];
     int cpu_dev, ret = -1;
-    snprintf(path, sizeof(path),
-        "/sys/devices/system/cpu/cpu%d/cpufreq/%s_cur_freq",
-        cpu, scaling ? "scaling" : "cpuinfo");
+    snprintf(path, sizeof(path), "/sys/devices/system/cpu/cpu%d/cpufreq/cpuinfo_cur_freq", cpu);
     cpu_dev = open(path, O_RDONLY);
     if (cpu_dev < 0)
         return -1;
     if (read(cpu_dev, temp, sizeof(temp)) >= 0)
-        ret = atoi(temp);
+        ret = atoi(temp) * FREQ_MULTIPLIER;
     close(cpu_dev);
     return ret;
 }
 
-#if defined(DX50) || defined(DX90)
 bool current_scaling_governor(int cpu, char* governor, int governor_size)
 {
     if((cpu < 0) || (governor == NULL) || (governor_size <= 0))
@@ -168,7 +171,7 @@ bool current_scaling_governor(int cpu, char* governor, int governor_size)
         return false;
     }
 
-    char path[PATH_MAX];
+    char path[64];
     snprintf(path,
              sizeof(path),
              "/sys/devices/system/cpu/cpu%d/cpufreq/scaling_governor",
@@ -212,13 +215,13 @@ static int read_cpu_frequency(int cpu, enum cpu_frequency_options freqOpt)
         return -1;
     }
 
-    char path[PATH_MAX];
+    char path[64];
     switch(freqOpt)
     {
         case SCALING_MIN_FREQ:
         {
             snprintf(path,
-                     PATH_MAX,
+                     sizeof(path),
                      "/sys/devices/system/cpu/cpu%d/cpufreq/scaling_min_freq",
                      cpu);
             break;
@@ -227,7 +230,7 @@ static int read_cpu_frequency(int cpu, enum cpu_frequency_options freqOpt)
         case SCALING_CUR_FREQ:
         {
             snprintf(path,
-                     PATH_MAX,
+                     sizeof(path),
                      "/sys/devices/system/cpu/cpu%d/cpufreq/scaling_cur_freq",
                      cpu);
             break;
@@ -236,7 +239,7 @@ static int read_cpu_frequency(int cpu, enum cpu_frequency_options freqOpt)
         case SCALING_MAX_FREQ:
         {
             snprintf(path,
-                     PATH_MAX,
+                     sizeof(path),
                      "/sys/devices/system/cpu/cpu%d/cpufreq/scaling_max_freq",
                      cpu);
             break;
@@ -264,7 +267,7 @@ static int read_cpu_frequency(int cpu, enum cpu_frequency_options freqOpt)
     }
 
     fclose(f);
-    return(freq);
+    return freq * FREQ_MULTIPLIER;
 }
 
 
@@ -284,7 +287,6 @@ int max_scaling_frequency(int cpu)
 {
     return(read_cpu_frequency(cpu, SCALING_MAX_FREQ));
 }
-#endif
 
 int cpustatetimes_linux(int cpu, struct time_state* data, int max_elements)
 {
diff --git a/firmware/target/hosted/cpuinfo-linux.h b/firmware/target/hosted/cpuinfo-linux.h
index 0483a3a9aa..defbf2f374 100644
--- a/firmware/target/hosted/cpuinfo-linux.h
+++ b/firmware/target/hosted/cpuinfo-linux.h
@@ -39,9 +39,12 @@ struct time_state {
 };
 
 int cpuusage_linux(struct cpuusage* u);
-int frequency_linux(int cpu, bool scaling);
+/* Return the frequency of a CPU. Note that whenever CPU frequency scaling is supported by the
+ * driver, this frequency may not be accurate and may vaguely reflect the cpu mode. Use
+ * current_scaling_frequency() to get the actual frequency if scaling is supported.
+ * Return -1 on error. */
+int frequency_linux(int cpu);
 
-#if defined(DX50) || defined(DX90)
 /*
     Get the current cpufreq scaling governor.
     cpu [in]: The number of the cpu to query.
@@ -60,7 +63,6 @@ bool current_scaling_governor(int cpu, char* governor, int governor_size);
 int min_scaling_frequency(int cpu);
 int current_scaling_frequency(int cpu);
 int max_scaling_frequency(int cpu);
-#endif
 
 int cpustatetimes_linux(int cpu, struct time_state* data, int max_elements);
 int cpucount_linux(void);