Sansa AMS: Disable DMA clocks when not in use

Add dma_retain() and dma_release() to reference count the users

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@19344 a1c6a512-1295-4272-9138-f99709370657

4 files changed, 30 insertions, 3 deletions

diff --git a/firmware/target/arm/as3525/ata_sd_as3525.c b/firmware/target/arm/as3525/ata_sd_as3525.c
index b71941adad..edde02b593 100644
--- a/firmware/target/arm/as3525/ata_sd_as3525.c
+++ b/firmware/target/arm/as3525/ata_sd_as3525.c
@@ -568,6 +568,8 @@ static int sd_transfer_sectors(IF_MV2(int drive,) unsigned long start,
         goto sd_transfer_error;
     }
 
+    dma_retain();
+
     while(count)
     {
         /* 128 * 512 = 2^16, and doesn't fit in the 16 bits of DATA_LENGTH
@@ -628,6 +630,8 @@ static int sd_transfer_sectors(IF_MV2(int drive,) unsigned long start,
 
     while (1)
     {
+        dma_release();
+
 #ifndef BOOTLOADER
         sd_enable(false);
 #endif
diff --git a/firmware/target/arm/as3525/dma-pl081.c b/firmware/target/arm/as3525/dma-pl081.c
index 3de4e73c12..8ec2919714 100644
--- a/firmware/target/arm/as3525/dma-pl081.c
+++ b/firmware/target/arm/as3525/dma-pl081.c
@@ -26,6 +26,7 @@
 #include "panic.h"
 #include "kernel.h"
 
+static int dma_used = 0;
 static struct wakeup transfer_completion_signal[2]; /* 2 channels */
 static void (*dma_callback[2])(void); /* 2 channels */
 
@@ -34,11 +35,26 @@ inline void dma_wait_transfer(int channel)
     wakeup_wait(&transfer_completion_signal[channel], TIMEOUT_BLOCK);
 }
 
+void dma_retain(void)
+{
+    if(++dma_used == 1)
+    {
+        CGU_PERI |= CGU_DMA_CLOCK_ENABLE;
+        DMAC_CONFIGURATION |= (1<<0);
+    }
+}
+
+void dma_release(void)
+{
+    if(--dma_used == 0)
+    {
+        DMAC_CONFIGURATION &= ~(1<<0);
+        CGU_PERI &= ~CGU_DMA_CLOCK_ENABLE;
+    }
+}
+
 void dma_init(void)
 {
-    /* Enable DMA controller */
-    CGU_PERI |= CGU_DMA_CLOCK_ENABLE;
-    DMAC_CONFIGURATION |= (1<<0);   /* TODO: disable controller when not used */
     DMAC_SYNC = 0;
     VIC_INT_ENABLE |= INTERRUPT_DMAC;
 
diff --git a/firmware/target/arm/as3525/dma-target.h b/firmware/target/arm/as3525/dma-target.h
index 26037999f0..6e373b89a6 100644
--- a/firmware/target/arm/as3525/dma-target.h
+++ b/firmware/target/arm/as3525/dma-target.h
@@ -37,3 +37,6 @@ void dma_enable_channel(int channel, void *src, void *dst, int peri,
                         size_t size, int nwords, void (*callback)(void));
 inline void dma_disable_channel(int channel);
 inline void dma_wait_transfer(int channel);
+
+void dma_retain(void);
+void dma_release(void);
diff --git a/firmware/target/arm/as3525/pcm-as3525.c b/firmware/target/arm/as3525/pcm-as3525.c
index cf0333f24c..e5cbdc48ee 100644
--- a/firmware/target/arm/as3525/pcm-as3525.c
+++ b/firmware/target/arm/as3525/pcm-as3525.c
@@ -94,6 +94,8 @@ void pcm_play_dma_start(const void *addr, size_t size)
     dma_size = size;
     dma_start_addr = (unsigned char*)addr;
 
+    dma_retain();
+
     play_start_pcm();
 }
 
@@ -102,6 +104,8 @@ void pcm_play_dma_stop(void)
     dma_disable_channel(1);
     dma_size = 0;
 
+    dma_release();
+
     CGU_PERI &= ~CGU_I2SOUT_APB_CLOCK_ENABLE;
     CGU_AUDIO &= ~(1<<11);
 }