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[15/15] dmaengine: dw-axi-dmac: Set constraint to the Max segment size

Message ID 20201012042200.29787-16-jee.heng.sia@intel.com (mailing list archive)
State Changes Requested
Headers show
Series dmaengine: dw-axi-dmac: support Intel KeemBay AxiDMA | expand

Commit Message

Sia Jee Heng Oct. 12, 2020, 4:22 a.m. UTC 
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.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Sia Jee Heng <jee.heng.sia@intel.com>
---
 drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 8 ++++++++
 drivers/dma/dw-axi-dmac/dw-axi-dmac.h          | 1 +
 2 files changed, 9 insertions(+)
diff mbox series

Patch

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 d4fca3ffe67f..bd56e21663c3 100644
--- 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>
@@ -1407,6 +1408,13 @@  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 f64e8d33b127..67669049cead 100644
--- 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;