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>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index 06f03914f022..ff39fa6cd2bc 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -172,6 +172,7 @@ struct dw_dma_regs {
 
 enum dw_dmac_flags {
         DW_DMA_IS_CYCLIC = 0,
+        DW_DMA_IS_SOFT_LLP = 1,
 };
 
 struct dw_dma_chan {
@@ -182,6 +183,10 @@ struct dw_dma_chan {
         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 @@ struct dw_dma_chan {
 
         /* hardware configuration */
         unsigned int            block_size;
+        bool                    nollp;
 
         /* configuration passed via DMA_SLAVE_CONFIG */
         struct dma_slave_config dma_sconfig;