dmaengine: dw-axi-dmac: Set constraint to the Max segment size

Add support for DMA Scatter-Gather (SG) constraint so that DMA clients can
handle the AxiDMA limitation.

Without supporting DMA constraint the default Max segment size reported by
dmaengine is 64KB, which is not supported by Intel KeemBay AxiDMA.

Signed-off-by: Sia Jee Heng <jee.heng.sia@intel.com>
Tested-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Link: https://lore.kernel.org/r/20210125013255.25799-17-jee.heng.sia@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
index a1dddec95316afab6780e225d1f2273f92e94bca..88d4923dee6c5e69056e320dd54c635b83ff565d 100644 (file)
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
@@ -12,6 +12,7 @@
 #include <linux/device.h>
 #include <linux/dmaengine.h>
 #include <linux/dmapool.h>
+#include <linux/dma-mapping.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
@@ -1340,6 +1341,13 @@ static int dw_probe(struct platform_device *pdev)
        dw->dma.device_prep_slave_sg = dw_axi_dma_chan_prep_slave_sg;
        dw->dma.device_prep_dma_cyclic = dw_axi_dma_chan_prep_cyclic;
 
+       /*
+        * Synopsis DesignWare AxiDMA datasheet mentioned Maximum
+        * supported blocks is 1024. Device register width is 4 bytes.
+        * Therefore, set constraint to 1024 * 4.
+        */
+       dw->dma.dev->dma_parms = &dw->dma_parms;
+       dma_set_max_seg_size(&pdev->dev, MAX_BLOCK_SIZE);
        platform_set_drvdata(pdev, chip);
 
        pm_runtime_enable(chip->dev);

diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
index 3a357f7fda0240d08cb5690bec19d6d00fc06fc1..1e937ea2a96dec6837987178f8d985f4dcb74126 100644 (file)
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
@@ -54,6 +54,7 @@ struct axi_dma_chan {
 struct dw_axi_dma {
        struct dma_device       dma;
        struct dw_axi_dma_hcfg  *hdata;
+       struct device_dma_parameters    dma_parms;
 
        /* channels */
        struct axi_dma_chan     *chan;