[PATCH] dmaengine: sun6i: Set the maximum segment size

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



The sun6i DMA engine supports segment sizes up to 2^25-1 bytes. This is
explicitly stated in newer SoC documentation (H6, D1), and it is implied
in older documentation by the 25-bit width of the "bytes left in the
current segment" register field.

Exposing the real segment size limit (instead of the 64k default)
reduces the number of SG list segments needed for a transaction.

Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>
---
Tested on A64, verified that the maximum ALSA PCM period increased, and
that audio playback still worked.

 drivers/dma/sun6i-dma.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
index b7557f437936..1425f87d97b7 100644
--- a/drivers/dma/sun6i-dma.c
+++ b/drivers/dma/sun6i-dma.c
@@ -9,6 +9,7 @@
 
 #include <linux/clk.h>
 #include <linux/delay.h>
+#include <linux/dma-mapping.h>
 #include <linux/dmaengine.h>
 #include <linux/dmapool.h>
 #include <linux/interrupt.h>
@@ -1334,6 +1335,8 @@ static int sun6i_dma_probe(struct platform_device *pdev)
 	INIT_LIST_HEAD(&sdc->pending);
 	spin_lock_init(&sdc->lock);
 
+	dma_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(25));
+
 	dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
 	dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
 	dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
-- 
2.35.1




[Index of Archives]     [Linux Kernel]     [Linux ARM (vger)]     [Linux ARM MSM]     [Linux Omap]     [Linux Arm]     [Linux Tegra]     [Fedora ARM]     [Linux for Samsung SOC]     [eCos]     [Linux PCI]     [Linux Fastboot]     [Gcc Help]     [Git]     [DCCP]     [IETF Announce]     [Security]     [Linux MIPS]     [Yosemite Campsites]

  Powered by Linux