dw_dmac: introduce software emulation of LLP transfers
Some controllers have the reduced functionality where the LLP multi block
transfers are not supported. This patch introduces a support of such
controllers. In case of memory copy or scatter-gather lists it emulates LLP
transfers via bunch of the regular single block ones.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index 06f0391..ff39fa6 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -172,6 +172,7 @@
enum dw_dmac_flags {
DW_DMA_IS_CYCLIC = 0,
+ DW_DMA_IS_SOFT_LLP = 1,
};
struct dw_dma_chan {
@@ -182,6 +183,10 @@
bool paused;
bool initialized;
+ /* software emulation of the LLP transfers */
+ struct list_head *tx_list;
+ struct list_head *tx_node_active;
+
spinlock_t lock;
/* these other elements are all protected by lock */
@@ -195,6 +200,7 @@
/* hardware configuration */
unsigned int block_size;
+ bool nollp;
/* configuration passed via DMA_SLAVE_CONFIG */
struct dma_slave_config dma_sconfig;