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* [V2] dmaengine: fsl-edma: support little endian for edma driver
@ 2019-06-13 10:27 Peng Ma
  2019-06-24 12:00 ` Vinod Koul
  0 siblings, 1 reply; 2+ messages in thread
From: Peng Ma @ 2019-06-13 10:27 UTC (permalink / raw)
  To: dan.j.williams, vkoul, leoyang.li; +Cc: dmaengine, linux-kernel, Peng Ma

Our platforms with below registers(CHCFG0 - CHCFG15) of eDMA
*-----------------------------------------------------------*
|     Offset   | Big endian Register| Little endian Register|
|--------------|--------------------|-----------------------|
|     0x0      |        CHCFG0      |           CHCFG3      |
|--------------|--------------------|-----------------------|
|     0x1      |        CHCFG1      |           CHCFG2      |
|--------------|--------------------|-----------------------|
|     0x2      |        CHCFG2      |           CHCFG1      |
|--------------|--------------------|-----------------------|
|     0x3      |        CHCFG3      |           CHCFG0      |
|--------------|--------------------|-----------------------|
|     ...      |        ......      |           ......      |
|--------------|--------------------|-----------------------|
|     0xC      |        CHCFG12     |           CHCFG15     |
|--------------|--------------------|-----------------------|
|     0xD      |        CHCFG13     |           CHCFG14     |
|--------------|--------------------|-----------------------|
|     0xE      |        CHCFG14     |           CHCFG13     |
|--------------|--------------------|-----------------------|
|     0xF      |        CHCFG15     |           CHCFG12     |
*-----------------------------------------------------------*

Current eDMA driver does not support Little endian, so this
patch is to improve edma driver to support little endian.

Signed-off-by: Peng Ma <peng.ma@nxp.com>
---
Changed fo v2:
	- Add details fo comments.

 drivers/dma/fsl-edma-common.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/dma/fsl-edma-common.c b/drivers/dma/fsl-edma-common.c
index 680b2a0..6bf238e 100644
--- a/drivers/dma/fsl-edma-common.c
+++ b/drivers/dma/fsl-edma-common.c
@@ -83,9 +83,14 @@ void fsl_edma_chan_mux(struct fsl_edma_chan *fsl_chan,
 	u32 ch = fsl_chan->vchan.chan.chan_id;
 	void __iomem *muxaddr;
 	unsigned int chans_per_mux, ch_off;
+	int endian_diff[4] = {3, 1, -1, -3};
 
 	chans_per_mux = fsl_chan->edma->n_chans / DMAMUX_NR;
 	ch_off = fsl_chan->vchan.chan.chan_id % chans_per_mux;
+
+	if (!fsl_chan->edma->big_endian)
+		ch_off += endian_diff[ch_off % 4];
+
 	muxaddr = fsl_chan->edma->muxbase[ch / chans_per_mux];
 	slot = EDMAMUX_CHCFG_SOURCE(slot);
 
-- 
1.7.1


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2019-06-13 10:27 [V2] dmaengine: fsl-edma: support little endian for edma driver Peng Ma
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