diff options
| author | Keith Packard <keithp@keithp.com> | 2012-04-06 22:39:45 -0700 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2012-04-06 22:39:45 -0700 |
| commit | 0bcc23c3be1a20a362fea268901c600f9f0d287a (patch) | |
| tree | f6fc4cc475779daddfeeda22c8e3f29eb834a8e4 /src | |
| parent | 20926b62a87154a846cb950dc542c737cd54826d (diff) | |
altos: Disable DMA unit when idle
Should save a bit of power
Signed-off-by: Keith Packard <keithp@keithp.com>
Diffstat (limited to 'src')
| -rw-r--r-- | src/stm/ao_dma_stm.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/src/stm/ao_dma_stm.c b/src/stm/ao_dma_stm.c index 70b9e48a..f996e7cd 100644 --- a/src/stm/ao_dma_stm.c +++ b/src/stm/ao_dma_stm.c @@ -27,6 +27,7 @@ uint8_t ao_dma_done[NUM_DMA]; static struct ao_dma_config ao_dma_config[NUM_DMA]; static uint8_t ao_dma_mutex[NUM_DMA]; +static uint8_t ao_dma_active; static void ao_dma_isr(uint8_t index) { @@ -58,10 +59,12 @@ ao_dma_set_transfer(uint8_t index, uint32_t ccr) { ao_mutex_get(&ao_dma_mutex[index]); + if (ao_dma_active++ == 0) + stm_rcc.ahbenr |= (1 << STM_RCC_AHBENR_DMA1EN); stm_dma.channel[index].ccr = ccr | (1 << STM_DMA_CCR_TCIE); stm_dma.channel[index].cndtr = count; - stm_dma.channel[index].cpar = (uint32_t) peripheral; - stm_dma.channel[index].cmar = (uint32_t) memory; + stm_dma.channel[index].cpar = peripheral; + stm_dma.channel[index].cmar = memory; } void @@ -75,6 +78,8 @@ void ao_dma_done_transfer(uint8_t index) { stm_dma.channel[index].ccr &= ~(1 << STM_DMA_CCR_EN); + if (--ao_dma_active == 0) + stm_rcc.ahbenr &= ~(1 << STM_RCC_AHBENR_DMA1EN); ao_mutex_put(&ao_dma_mutex[index]); } @@ -89,8 +94,6 @@ ao_dma_init(void) { int index; - stm_rcc.ahbenr |= (1 << STM_RCC_AHBENR_DMA1EN); - for (index = 0; index < STM_NUM_DMA; index++) { stm_nvic_set_enable(STM_ISR_DMA1_CHANNEL1_POS + index); stm_nvic_set_priority(STM_ISR_DMA1_CHANNEL1_POS + index, 4); |