[PATCH 3/3] dmaengine: pl330: support transfer unaligned with (burst len * burst size)

From: Shawn Lin
Date: Thu Aug 04 2016 - 23:10:38 EST


Currently pl330 doesn't support transfer which doesn't
align with burst len * burst size. This should be only
for single mode. Let's allow it for busrt mode if available.

e.g. transfers 0x10002 bytes:
First loop 256*16*16=0x10000, burst size is 1, burst length is 16.
Then the second loop 2 bytes, burst size is 1, burst length is 1.

f0041000: DMAMOV CCR 0xbc02f1
f0041006: DMAMOV SAR 0xdd6c0000
f004100c: DMAMOV DAR 0xff1d0400
f0041012: DMALP_0 15
f0041014: DMALP_1 255
f0041016: DMAWFPB 12
f0041018: DMALDA
f0041019: DMASTPB 12
f004101b: DMAFLUSHP 12
f004101d: DMALPENDA_1 bjmpto_7
f004101f: DMALPENDA_0 bjmpto_b
f0041021: DMAMOV CCR 0x800201
f0041027: DMALP_1 1
f0041029: DMAWFPB 12
f004102b: DMALDA
f004102c: DMASTPB 12
f004102e: DMAFLUSHP 12
f0041030: DMALPENDA_1 bjmpto_7
f0041032: DMASEV 0
f0041034: DMAEND

Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
---

drivers/dma/pl330.c | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index a09bf22..cdb4afc 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -240,6 +240,7 @@ enum pl330_byteswap {

#define BYTE_TO_BURST(b, ccr) ((b) / BRST_SIZE(ccr) / BRST_LEN(ccr))
#define BURST_TO_BYTE(c, ccr) ((c) * BRST_SIZE(ccr) * BRST_LEN(ccr))
+#define BYTE_MOD_BURST_LEN(b, ccr) (((b) / BRST_SIZE(ccr)) % BRST_LEN(ccr))

/*
* With 256 bytes, we can do more than 2.5MB and 5MB xfers per req
@@ -1331,6 +1332,19 @@ static inline int _setup_xfer(struct pl330_dmac *pl330,
/* Setup Loop(s) */
off += _setup_loops(pl330, dry_run, &buf[off], pxs);

+ if (pl330->peripherals_req_type == BURST) {
+ unsigned int ccr = pxs->ccr;
+ unsigned long c = 0;
+
+ c = BYTE_MOD_BURST_LEN(x->bytes, pxs->ccr);
+ if (c) {
+ ccr &= ~(0xf << CC_SRCBRSTLEN_SHFT);
+ ccr &= ~(0xf << CC_DSTBRSTLEN_SHFT);
+ off += _emit_MOV(dry_run, &buf[off], CCR, ccr);
+ off += _loop(pl330, dry_run, &buf[off], &c, pxs);
+ }
+ }
+
return off;
}

@@ -1353,9 +1367,12 @@ static int _setup_req(struct pl330_dmac *pl330, unsigned dry_run,
off += _emit_MOV(dry_run, &buf[off], CCR, pxs->ccr);

x = &pxs->desc->px;
- /* Error if xfer length is not aligned at burst size */
- if (x->bytes % (BRST_SIZE(pxs->ccr) * BRST_LEN(pxs->ccr)))
- return -EINVAL;
+
+ if (pl330->peripherals_req_type != BURST) {
+ /* Error if xfer length is not aligned at burst size */
+ if (x->bytes % (BRST_SIZE(pxs->ccr) * BRST_LEN(pxs->ccr)))
+ return -EINVAL;
+ }

off += _setup_xfer(pl330, dry_run, &buf[off], pxs);

--
2.3.7