dmaengine: dw: override LLP support if asked in platform data

There are at least two known devices, e.g. DMA controller found on ARC AXS101
SDP board, that have LLP register and no multi block transfer support at the
same time.

Override autodetection by user provided data.

Reported-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Reviewed-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index 80e7421..da18b18 100644 (file)
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -1571,11 +1571,7 @@ int dw_dma_probe(struct dw_dma_chip *chip)
                                (dwc_params >> DWC_PARAMS_MBLK_EN & 0x1) == 0;
                } else {
                        dwc->block_size = pdata->block_size;
-
-                       /* Check if channel supports multi block transfer */
-                       channel_writel(dwc, LLP, DWC_LLP_LOC(0xffffffff));
-                       dwc->nollp = DWC_LLP_LOC(channel_readl(dwc, LLP)) == 0;
-                       channel_writel(dwc, LLP, 0);
+                       dwc->nollp = pdata->is_nollp;
                }
        }
 

diff --git a/include/linux/platform_data/dma-dw.h b/include/linux/platform_data/dma-dw.h
index 4636c93..5f0e11e 100644 (file)
--- a/include/linux/platform_data/dma-dw.h
+++ b/include/linux/platform_data/dma-dw.h
@@ -40,6 +40,7 @@ struct dw_dma_slave {
  * @is_private: The device channels should be marked as private and not for
  *     by the general purpose DMA channel allocator.
  * @is_memcpy: The device channels do support memory-to-memory transfers.
+ * @is_nollp: The device channels does not support multi block transfers.
  * @chan_allocation_order: Allocate channels starting from 0 or 7
  * @chan_priority: Set channel priority increasing from 0 to 7 or 7 to 0.
  * @block_size: Maximum block size supported by the controller
@@ -51,6 +52,7 @@ struct dw_dma_platform_data {
        unsigned int    nr_channels;
        bool            is_private;
        bool            is_memcpy;
+       bool            is_nollp;
 #define CHAN_ALLOCATION_ASCENDING      0       /* zero to seven */
 #define CHAN_ALLOCATION_DESCENDING     1       /* seven to zero */
        unsigned char   chan_allocation_order;