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SAML21 DMA: BASEADDR and WRBADDR can only be written while the DMAC is disabled

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This commit is contained in:
Gregory Nutt 2015-06-14 11:46:44 -06:00
parent a13a691bff
commit e6df02fc17
1 changed files with 9 additions and 15 deletions
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24
arch/arm/src/samdl/sam_dmac.c
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@ -618,11 +618,7 @@ static int sam_single(struct sam_dmach_s *dmach)
{
struct dma_desc_s *head = &g_base_desc[dmach->dc_chan];
/* Clear any pending interrupts from any previous DMAC transfer.
*
* REVISIT: If DMAC interrupts are disabled at the NVIKC, then reading the
* EBCISR register could cause a loss of interrupts!
*/
/* Clear any pending interrupts from any previous DMAC transfer. */
#warning Missing logic
/* Set up the DMA */
@ -651,11 +647,7 @@ static int sam_multiple(struct sam_dmach_s *dmach)
{
struct dma_desc_s *head = &g_base_desc[dmach->dc_chan];
/* Clear any pending interrupts from any previous DMAC transfer.
*
* REVISIT: If DMAC interrupts are disabled at the NVIKC, then reading the
* EBCISR register could cause a loss of interrupts!
*/
/* Clear any pending interrupts from any previous DMAC transfer. */
#warning Missing logic
/* Set up the initial DMA */
@ -729,15 +721,17 @@ void weak_function up_dmainitialize(void)
(void)irq_attach(SAM_IRQ_DMAC, sam_dmainterrupt);
/* Enable the DMA controller */
putreg16(DMAC_CTRL_DMAENABLE, SAM_DMAC_CTRL);
/* Set the LPRAM DMA descriptor table addresses */
/* Set the LPRAM DMA descriptor table addresses. These can only be
* written when the DMAC is disabled.
*/
putreg32((uint32_t)g_base_desc, SAM_DMAC_BASEADDR);
putreg32((uint32_t)g_writeback_desc, SAM_DMAC_WRBADDR);
/* Enable the DMA controller */
putreg16(DMAC_CTRL_DMAENABLE, SAM_DMAC_CTRL);
/* Enable the IRQ at the NVIC (still disabled at the DMA controller) */
up_enable_irq(SAM_IRQ_DMAC);