Introduce HW_SAMPR_MIN_GE_22 macro

Gives us the lowest HW sample rate that's >= 22KHz.

Needed because some targets that don't support 22K support 11K or 8K, so
HW_SAMPR_MIN will give us much lower quality than is acceptable.

Take advantage of this new macro in the SDL, MIDI, and MIKMOD plugins,
and implement a crude "fast enough" test to enable higher sample rates
on more capable targets.

Change-Id: I6ad38026fb3410c62da028e78512e027729bb851

apps/plugins/midi/midiutil.h

@@ -27,28 +27,67 @@
 #define NBUF   2
 #define MAX_SAMPLES 512
 
-#ifndef SIMULATOR
+#ifdef SIMULATOR
 
-#define SAMPLE_RATE SAMPR_44        /* 44100 */
+/* Simulator requires 44100Hz, and we can afford to use more voices */
+#define SAMPLE_RATE SAMPR_44
+#define MAX_VOICES 48
+
+#elif (CONFIG_PLATFORM & PLATFORM_HOSTED)
+
+/* All hosted targets have CPU to spare */
+#define MAX_VOICES 48
+#define SAMPLE_RATE SAMPR_44
+
+#elif defined(CPU_PP)
 
 /* Some of the pp based targets can't handle too many voices
    mainly because they have to use 44100Hz sample rate, this could be
    improved to increase MAX_VOICES for targets that can do 22kHz */
-#ifdef CPU_PP
-#define MAX_VOICES 16
-#elif (CONFIG_PLATFORM & PLATFORM_HOSTED)
-#define MAX_VOICES 48
+#define SAMPLE_RATE HW_SAMPR_MIN_GE_22
+#if HW_SAMPR_CAPS & SAMPR_CAP_22
+#define MAX_VOICES 24 /* General MIDI minimum */
 #else
-#define MAX_VOICES 24 /* Note: 24 midi channels is the minimum general midi spec implementation */
-#endif /* CPU_PP */
-
-#else   /* Simulator requires 44100Hz, and we can afford to use more voices */
-
-#define SAMPLE_RATE SAMPR_44
-#define MAX_VOICES 48
-
+#define MAX_VOICES 16
 #endif
 
+#elif defined(CPU_MIPS)
+
+/* All MIPS targets are pretty fast */
+#define MAX_VOICES 48
+#define SAMPLE_RATE SAMPR_44
+
+#elif defined(CPU_ARM)
+
+/* ARMv4 targets are slow, but treat everything else as fast */
+
+#if (ARM_ARCH >= 6)
+#define MAX_VOICES 32
+#define SAMPLE_RATE SAMPR_44
+#elif (ARM_ARCH >= 5)
+#define MAX_VOICES 32
+#define SAMPLE_RATE HW_SAMPR_MIN_GE_22
+#else /* ie v4 */
+#define SAMPLE_RATE HW_SAMPR_MIN_GE_22
+#if HW_SAMPR_CAPS & SAMPR_CAP_22
+#define MAX_VOICES 24 /* General MIDI minimum */
+#else
+#define MAX_VOICES 16
+#endif
+#endif /* ARM_ARCH < 5*/
+
+#else /* !CPU_ARM */
+
+/* Treat everything else as slow */
+#define SAMPLE_RATE HW_SAMPR_MIN_GE_22
+#if HW_SAMPR_CAPS & SAMPR_CAP_22
+#define MAX_VOICES 24 /* General MIDI minimum */
+#else
+#define MAX_VOICES 16
+#endif
+
+#endif /* Wrap it up. */
+
 #define BYTE unsigned char
 
 /* Data chunk ID types, returned by readID() */

apps/plugins/mikmod/mikmod_supp.h

@@ -63,8 +63,29 @@ int mmsupp_sprintf(char *buf, const char *fmt, ... );
 
 extern const struct plugin_api * rb;
 
+#ifdef SIMULATOR
 
-#define SAMPLE_RATE SAMPR_44        /* 44100 */
+#define SAMPLE_RATE SAMPR_44  /* Required by Simulator */
+
+#elif ((CONFIG_PLATFORM & PLATFORM_HOSTED) || defined(CPU_MIPS))
+
+#define SAMPLE_RATE SAMPR_44 /* All MIPS and hosted targets are fast */
+
+#elif defined(CPU_ARM)
+
+/* Treat ARMv5+ as fast */
+#if (ARM_ARCH >= 5)
+#define SAMPLE_RATE SAMPR_44
+#else
+#define SAMPLE_RATE SAMPR_MIN_GE_22
+#endif
+
+#else /* !CPU_ARM */
+
+/* Treat everyone else as slow */
+#define SAMPLE_RATE HW_SAMPR_MIN_GE_22
+
+#endif /* !SIMULATOR */
 
 #define BUF_SIZE 4096*8
 #define NBUF   2

apps/plugins/sdl/include/SDL_config_rockbox.h

@@ -47,11 +47,7 @@
 #ifdef SIMULATOR
 #define RB_SAMPR SAMPR_44
 #else
-#if HW_SAMPR_CAPS & SAMPR_CAP_22
-#define RB_SAMPR SAMPR_22
-#else
-#define RB_SAMPR HW_SAMPR_MIN
-#endif
+#define RB_SAMPR HW_SAMPR_MIN_GE_22 /* Min HW rate at least 22KHz */
 #endif
 
 /* Enable the stub cdrom driver (src/cdrom/dummy/\*.c) */

firmware/export/pcm_sampr.h

@@ -80,6 +80,11 @@
                          SAMPR_CAP_24 | SAMPR_CAP_22 | SAMPR_CAP_16 | \
                          SAMPR_CAP_12 | SAMPR_CAP_11 | SAMPR_CAP_8)
 
+/* List of sampling rates that are good enough for most purposes. */
+#define SAMPR_CAP_ALL_GE_22   (SAMPR_CAP_96 | SAMPR_CAP_88 | SAMPR_CAP_64 | \
+                               SAMPR_CAP_48 | SAMPR_CAP_44 | SAMPR_CAP_32 | \
+                               SAMPR_CAP_24 | SAMPR_CAP_22)
+
 #ifndef PCM_SAMPR_CONFIG_ONLY
 /* Master list of all "standard" rates supported. */
 extern const unsigned long audio_master_sampr_list[SAMPR_NUM_FREQ];
@@ -231,6 +236,17 @@ extern const unsigned long hw_freq_sampr[HW_NUM_FREQ];
 # define HW_SAMPR_MIN   SAMPR_44
 #endif
 
+#define HW_SAMPR_CAPS_QUAL (HW_SAMPR_CAPS & SAMPR_CAP_ALL_GE_22)
+#if HW_SAMPR_CAPS_QUAL & SAMPR_CAP_22
+# define HW_SAMPR_MIN_GE_22  SAMPR_22
+#elif HW_SAMPR_CAPS_QUAL & SAMPR_CAP_24
+# define HW_SAMPR_MIN_GE_22  SAMPR_24
+#elif HW_SAMPR_CAPS_QUAL & SAMPR_CAP_32
+# define HW_SAMPR_MIN_GE_22  SAMPR_32
+#else
+# define HW_SAMPR_MIN_GE_22  SAMPR_44
+#endif
+
 #ifdef HAVE_RECORDING
 
 #ifndef PCM_SAMPR_CONFIG_ONLY