5 files changed, 119 insertions, 27 deletions

diff --git a/firmware/drivers/rds.c b/firmware/drivers/rds.c
index 09bc33807c..828c28b672 100644
--- a/firmware/drivers/rds.c
+++ b/firmware/drivers/rds.c
@@ -36,14 +36,46 @@ static char rt_copy[65];
 static int rt_segment;
 static int rt_abflag;
 
+#ifdef SI4700_RDS_ASYNC
+/* Functions are called in ISR context */
+#define rds_disable_irq_save() disable_irq_save()
+#define rds_restore_irq(old) restore_irq(old)
+/* Need triple buffer so string isn't clobbered while caller is using it */
+static inline char * get_ps(void)
+{
+    static char ps_out[9];
+    int oldlevel = rds_disable_irq_save();
+    strcpy(ps_out, ps_copy);
+    rds_restore_irq(oldlevel);
+    return ps_out;
+}
+static inline char * get_rt(void)
+{
+    static char rt_out[65];
+    int oldlevel = rds_disable_irq_save();
+    strcpy(rt_out, rt_copy);
+    rds_restore_irq(oldlevel);
+    return rt_out;
+}
+#else /* ndef SI4700_RDS_ASYNC */
+#define rds_disable_irq_save() 0
+#define rds_restore_irq(old) ((void)(old))
+static inline char * get_ps(void) { return ps_copy; }
+static inline char * get_rt(void) { return rt_copy; }
+#endif /* SI4700_RDS_ASYNC */
+
 /* resets the rds parser */
 void rds_reset(void)
 {
+    int oldlevel = rds_disable_irq_save();
+
     ps_copy[0] = '\0';
     ps_segment = 0;
     rt_copy[0] = '\0';
     rt_segment = 0;
     pi = 0;
+
+    rds_restore_irq(oldlevel);
 }
 
 /* initialises the rds parser */
@@ -172,6 +204,9 @@ bool rds_process(uint16_t data[4])
     return false;
 }
 
+/* TODO: The caller really should provide the buffer in order to regulate
+   access */
+
 /* returns the programme identification code */
 uint16_t rds_get_pi(void)
 {
@@ -181,12 +216,12 @@ uint16_t rds_get_pi(void)
 /* returns the most recent valid programme service name */
 char* rds_get_ps(void)
 {
-    return ps_copy;
+    return get_ps();
 }
 
 /* returns the most recent valid RadioText message */
 char* rds_get_rt(void)
 {
-    return rt_copy;
+    return get_rt();
 }
 
diff --git a/firmware/drivers/tuner/si4700.c b/firmware/drivers/tuner/si4700.c
index bebbd0c881..0684d2042f 100644
--- a/firmware/drivers/tuner/si4700.c
+++ b/firmware/drivers/tuner/si4700.c
@@ -556,6 +556,34 @@ void si4700_dbg_info(struct si4700_dbg_info *nfo)
 }
 
 #ifdef HAVE_RDS_CAP
+
+#ifdef SI4700_RDS_ASYNC
+/* Read raw RDS info for processing - asynchronously */
+
+/* Assumes regbuf is 32 bytes */
+void si4700_rds_read_raw_async(void)
+{
+    si4700_read_raw_async((RDSD - STATUSRSSI + 1) * 2);
+}
+
+void si4700_rds_read_raw_async_complete(unsigned char *regbuf,
+                                        uint16_t data[4])
+{
+    const int index = (RDSA - STATUSRSSI) * 2;
+
+    for (int i = 0; i < 4; i++) {
+        data[i] = regbuf[index] << 8 | regbuf[index + 1];
+        regbuf += 2;
+    }
+}
+
+/* Set the event flag */
+void si4700_rds_set_event(void)
+{
+    rds_event = 1;
+}
+
+#else
 /* Read raw RDS info for processing */
 bool si4700_rds_read_raw(uint16_t data[4])
 {
@@ -582,6 +610,7 @@ void si4700_rds_set_event(void)
     rds_event = 1;
     mutex_unlock(&fmr_mutex);
 }
+#endif /* SI4700_RDS_ASYNC */
 
 char * si4700_get_rds_info(int setting)
 {
diff --git a/firmware/export/config/gigabeats.h b/firmware/export/config/gigabeats.h
index 04e7b156b6..9a34791ab1 100644
--- a/firmware/export/config/gigabeats.h
+++ b/firmware/export/config/gigabeats.h
@@ -90,6 +90,7 @@
 #define CONFIG_TUNER SI4700
 
 #define HAVE_RDS_CAP
+#define SI4700_RDS_ASYNC
 
 /* Define this if you have the WM8978 audio codec */
 #define HAVE_WM8978
@@ -163,7 +164,7 @@
 #define GPIO_EVENT_MASK (USE_GPIO1_EVENTS)
 
 /* Define this if target has an additional number of threads specific to it */
-#define TARGET_EXTRA_THREADS 3
+#define TARGET_EXTRA_THREADS 2
 
 /* Type of mobile power - check this out */
 #define BATTERY_CAPACITY_DEFAULT 700 /* default battery capacity */
diff --git a/firmware/export/si4700.h b/firmware/export/si4700.h
index 761ad1ca24..fe55dd3853 100644
--- a/firmware/export/si4700.h
+++ b/firmware/export/si4700.h
@@ -44,10 +44,18 @@ bool si4700_st(void);
 
 /** RDS support **/
 void si4700_rds_init(void);
-/* Read raw RDS info for processing */
-bool si4700_rds_read_raw(uint16_t data[4]);
 /* Radio is fully powered up or about to be powered down */
 void si4700_rds_powerup(bool on);
+#ifdef SI4700_RDS_ASYNC
+/* Read raw RDS info for processing - asynchronously */
+void si4700_read_raw_async(int count);
+void si4700_rds_read_raw_async(void);
+void si4700_rds_read_raw_async_complete(unsigned char *regbuf,
+                                        uint16_t data[4]);
+#else
+/* Read raw RDS info for processing */
+bool si4700_rds_read_raw(uint16_t data[4]);
+#endif
 /* Obtain specified string */
 char* si4700_get_rds_info(int setting);
 /* Set the event flag */
diff --git a/firmware/target/arm/imx31/gigabeat-s/fmradio-i2c-gigabeat-s.c b/firmware/target/arm/imx31/gigabeat-s/fmradio-i2c-gigabeat-s.c
index e0457e367a..a7b9bc21da 100644
--- a/firmware/target/arm/imx31/gigabeat-s/fmradio-i2c-gigabeat-s.c
+++ b/firmware/target/arm/imx31/gigabeat-s/fmradio-i2c-gigabeat-s.c
@@ -128,15 +128,52 @@ bool si4700_st(void)
 
 
 /* Low-level RDS Support */
-static struct semaphore rds_sema;
-static uint32_t rds_stack[DEFAULT_STACK_SIZE/sizeof(uint32_t)];
 
-/* RDS GPIO interrupt handler */
+/* Transfer descriptor for RDS async operations */
+struct si4700_i2c_transfer_desc
+{
+    struct i2c_transfer_desc xfer;
+    unsigned char regbuf[32];
+} si4700_xfer =
+{
+    .xfer = { .node = &si4700_i2c_node }
+};
+
+static void si4700_rds_read_raw_callback(struct i2c_transfer_desc *xfer)
+{
+    struct si4700_i2c_transfer_desc *xf =
+        (struct si4700_i2c_transfer_desc *)xfer;
+
+    if (xfer->rxcount != 0)
+        return; /* Read didn't finish */
+
+    uint16_t rds_data[4];
+
+    si4700_rds_read_raw_async_complete(xf->regbuf, rds_data);
+
+    if (rds_process(rds_data))
+        si4700_rds_set_event();
+}
+
+/* Callback from si4700_rds_read_raw to execute the read */
+void si4700_read_raw_async(int count)
+{
+    si4700_xfer.xfer.txdata = NULL;
+    si4700_xfer.xfer.txcount = 0;
+    si4700_xfer.xfer.rxdata = si4700_xfer.regbuf;
+    si4700_xfer.xfer.rxcount = count;
+    si4700_xfer.xfer.callback = si4700_rds_read_raw_callback;
+    si4700_xfer.xfer.next = NULL;
+
+    i2c_transfer(&si4700_xfer.xfer);
+}
+
+/* RDS GPIO interrupt handler - start RDS data read */
 void si4700_stc_rds_event(void)
 {
     /* read and clear the interrupt */
     SI4700_GPIO_STC_RDS_ISR = (1ul << SI4700_GPIO_STC_RDS_LINE);
-    semaphore_release(&rds_sema);
+    si4700_rds_read_raw_async(); 
 }
 
 /* Called with on=true after full radio power up, and with on=false before
@@ -152,26 +189,8 @@ void si4700_rds_powerup(bool on)
     }
 }
 
-/* Captures RDS data and processes it */
-/* Use of a thread here is likely temporary */
-static void NORETURN_ATTR rds_thread(void)
-{
-    uint16_t rds_data[4];
-
-    while (1)
-    {
-        semaphore_wait(&rds_sema, TIMEOUT_BLOCK);
-
-        if (si4700_rds_read_raw(rds_data) && rds_process(rds_data))
-            si4700_rds_set_event();
-    }
-}
-
 /* One-time RDS init at startup */
 void si4700_rds_init(void)
 {
-    semaphore_init(&rds_sema, 1, 0);
     rds_init();
-    create_thread(rds_thread, rds_stack, sizeof(rds_stack), 0, "rds"
-                  IF_PRIO(, PRIORITY_REALTIME) IF_COP(, CPU));    
 }