[V2] dmaengine: fsl-edma: support little endian for edma driver
From: Peng Ma
Date: Thu Jun 13 2019 - 11:38:28 EST
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@xxxxxxx>
---
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