Do DMAFLUSHP _before_ the first DMAWFP to ensure controller and peripheral are in agreement about dma request state before first transfer. Add support for burst transfers to/from peripherals. In the new scheme, the controller does as many burst transfers as it can then transfers the remaining dregs with either single transfers for peripherals, or with a reduced size burst for memory-to-memory transfers.
Signed-off-by: Frank Mori Hess <fmh...@gmail.com> Tested-by: Frank Mori Hess <fmh...@gmail.com> I tested dma transfers to peripherals with designware serial port (drivers/tty/serial/8250/8250_dw.c) and a GPIB interface (https://github.com/fmhess/fmh_gpib_core). I tested memory-to-memory transfers using the dmatest module. v3 of this patch should be the same as v2 except with checkpatch.pl warnings and errors cleaned up. --- drivers/dma/pl330.c | 146 +++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 104 insertions(+), 42 deletions(-) diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index d7327fd5f445..cc2e4456bec1 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -1094,26 +1094,33 @@ static inline int _ldst_memtomem(unsigned dry_run, u8 buf[], return off; } -static inline int _ldst_devtomem(struct pl330_dmac *pl330, unsigned dry_run, - u8 buf[], const struct _xfer_spec *pxs, - int cyc) +static inline int _ldst_devtomem(struct pl330_dmac *pl330, + unsigned int dry_run, u8 buf[], + const struct _xfer_spec *pxs, + int cyc, enum pl330_cond cond) { int off = 0; - enum pl330_cond cond; if (pl330->quirks & PL330_QUIRK_BROKEN_NO_FLUSHP) cond = BURST; - else - cond = SINGLE; + /* do FLUSHP at beginning to clear any stale dma requests before the + * first WFP. + */ + if (!(pl330->quirks & PL330_QUIRK_BROKEN_NO_FLUSHP)) + off += _emit_FLUSHP(dry_run, &buf[off], pxs->desc->peri); while (cyc--) { off += _emit_WFP(dry_run, &buf[off], cond, pxs->desc->peri); - off += _emit_LDP(dry_run, &buf[off], cond, pxs->desc->peri); + if (cond == ALWAYS) { + off += _emit_LDP(dry_run, &buf[off], SINGLE, + pxs->desc->peri); + off += _emit_LDP(dry_run, &buf[off], BURST, + pxs->desc->peri); + } else { + off += _emit_LDP(dry_run, &buf[off], cond, + pxs->desc->peri); + } off += _emit_ST(dry_run, &buf[off], ALWAYS); - - if (!(pl330->quirks & PL330_QUIRK_BROKEN_NO_FLUSHP)) - off += _emit_FLUSHP(dry_run, &buf[off], - pxs->desc->peri); } return off; @@ -1121,24 +1128,31 @@ static inline int _ldst_devtomem(struct pl330_dmac *pl330, unsigned dry_run, static inline int _ldst_memtodev(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[], - const struct _xfer_spec *pxs, int cyc) + const struct _xfer_spec *pxs, int cyc, + enum pl330_cond cond) { int off = 0; - enum pl330_cond cond; if (pl330->quirks & PL330_QUIRK_BROKEN_NO_FLUSHP) cond = BURST; - else - cond = SINGLE; + /* do FLUSHP at beginning to clear any stale dma requests before the + * first WFP. + */ + if (!(pl330->quirks & PL330_QUIRK_BROKEN_NO_FLUSHP)) + off += _emit_FLUSHP(dry_run, &buf[off], pxs->desc->peri); while (cyc--) { off += _emit_WFP(dry_run, &buf[off], cond, pxs->desc->peri); off += _emit_LD(dry_run, &buf[off], ALWAYS); - off += _emit_STP(dry_run, &buf[off], cond, pxs->desc->peri); - - if (!(pl330->quirks & PL330_QUIRK_BROKEN_NO_FLUSHP)) - off += _emit_FLUSHP(dry_run, &buf[off], - pxs->desc->peri); + if (cond == ALWAYS) { + off += _emit_STP(dry_run, &buf[off], SINGLE, + pxs->desc->peri); + off += _emit_STP(dry_run, &buf[off], BURST, + pxs->desc->peri); + } else { + off += _emit_STP(dry_run, &buf[off], cond, + pxs->desc->peri); + } } return off; @@ -1148,13 +1162,16 @@ static int _bursts(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[], const struct _xfer_spec *pxs, int cyc) { int off = 0; + enum pl330_cond cond = BRST_LEN(pxs->ccr) > 1 ? BURST : SINGLE; switch (pxs->desc->rqtype) { case DMA_MEM_TO_DEV: - off += _ldst_memtodev(pl330, dry_run, &buf[off], pxs, cyc); + off += _ldst_memtodev(pl330, dry_run, &buf[off], pxs, cyc, + cond); break; case DMA_DEV_TO_MEM: - off += _ldst_devtomem(pl330, dry_run, &buf[off], pxs, cyc); + off += _ldst_devtomem(pl330, dry_run, &buf[off], pxs, cyc, + cond); break; case DMA_MEM_TO_MEM: off += _ldst_memtomem(dry_run, &buf[off], pxs, cyc); @@ -1167,6 +1184,46 @@ static int _bursts(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[], return off; } +/* transfer dregs with single transfers to peripheral, or a reduced size burst + * for mem-to-mem. + */ +static int _dregs(struct pl330_dmac *pl330, unsigned int dry_run, u8 buf[], + const struct _xfer_spec *pxs, int transfer_length) +{ + int off = 0; + int dregs_ccr; + + if (transfer_length == 0) + return off; + + switch (pxs->desc->rqtype) { + case DMA_MEM_TO_DEV: + off += _ldst_memtodev(pl330, dry_run, &buf[off], pxs, + transfer_length, SINGLE); + break; + case DMA_DEV_TO_MEM: + off += _ldst_devtomem(pl330, dry_run, &buf[off], pxs, + transfer_length, SINGLE); + break; + case DMA_MEM_TO_MEM: + dregs_ccr = pxs->ccr; + dregs_ccr &= ~((0xf << CC_SRCBRSTLEN_SHFT) | + (0xf << CC_DSTBRSTLEN_SHFT)); + dregs_ccr |= (((transfer_length - 1) & 0xf) << + CC_SRCBRSTLEN_SHFT); + dregs_ccr |= (((transfer_length - 1) & 0xf) << + CC_DSTBRSTLEN_SHFT); + off += _emit_MOV(dry_run, &buf[off], CCR, dregs_ccr); + off += _ldst_memtomem(dry_run, &buf[off], pxs, 1); + break; + default: + off += 0x40000000; /* Scare off the Client */ + break; + } + + return off; +} + /* Returns bytes consumed and updates bursts */ static inline int _loop(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[], unsigned long *bursts, const struct _xfer_spec *pxs) @@ -1256,6 +1313,8 @@ static inline int _setup_loops(struct pl330_dmac *pl330, struct pl330_xfer *x = &pxs->desc->px; u32 ccr = pxs->ccr; unsigned long c, bursts = BYTE_TO_BURST(x->bytes, ccr); + int num_dregs = (x->bytes - BURST_TO_BYTE(bursts, ccr)) / + BRST_SIZE(ccr); int off = 0; while (bursts) { @@ -1263,6 +1322,7 @@ static inline int _setup_loops(struct pl330_dmac *pl330, off += _loop(pl330, dry_run, &buf[off], &c, pxs); bursts -= c; } + off += _dregs(pl330, dry_run, &buf[off], pxs, num_dregs); return off; } @@ -1294,7 +1354,6 @@ static int _setup_req(struct pl330_dmac *pl330, unsigned dry_run, struct _xfer_spec *pxs) { struct _pl330_req *req = &thrd->req[index]; - struct pl330_xfer *x; u8 *buf = req->mc_cpu; int off = 0; @@ -1303,11 +1362,6 @@ static int _setup_req(struct pl330_dmac *pl330, unsigned dry_run, /* DMAMOV CCR, ccr */ 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; - off += _setup_xfer(pl330, dry_run, &buf[off], pxs); /* DMASEV peripheral/event */ @@ -2115,15 +2169,29 @@ static int pl330_config(struct dma_chan *chan, pch->fifo_addr = slave_config->dst_addr; if (slave_config->dst_addr_width) pch->burst_sz = __ffs(slave_config->dst_addr_width); - if (slave_config->dst_maxburst) - pch->burst_len = slave_config->dst_maxburst; + if (pch->dmac->quirks & PL330_QUIRK_BROKEN_NO_FLUSHP) + pch->burst_len = 1; + else if (slave_config->dst_maxburst) { + if (slave_config->dst_maxburst > PL330_MAX_BURST) + pch->burst_len = PL330_MAX_BURST; + else + pch->burst_len = slave_config->dst_maxburst; + } else + pch->burst_len = 1; } else if (slave_config->direction == DMA_DEV_TO_MEM) { if (slave_config->src_addr) pch->fifo_addr = slave_config->src_addr; if (slave_config->src_addr_width) pch->burst_sz = __ffs(slave_config->src_addr_width); - if (slave_config->src_maxburst) - pch->burst_len = slave_config->src_maxburst; + if (pch->dmac->quirks & PL330_QUIRK_BROKEN_NO_FLUSHP) + pch->burst_len = 1; + else if (slave_config->src_maxburst) { + if (slave_config->src_maxburst > PL330_MAX_BURST) + pch->burst_len = PL330_MAX_BURST; + else + pch->burst_len = slave_config->src_maxburst; + } else + pch->burst_len = 1; } return 0; @@ -2517,14 +2585,8 @@ static inline int get_burst_len(struct dma_pl330_desc *desc, size_t len) burst_len >>= desc->rqcfg.brst_size; /* src/dst_burst_len can't be more than 16 */ - if (burst_len > 16) - burst_len = 16; - - while (burst_len > 1) { - if (!(len % (burst_len << desc->rqcfg.brst_size))) - break; - burst_len--; - } + if (burst_len > PL330_MAX_BURST) + burst_len = PL330_MAX_BURST; return burst_len; } @@ -2596,7 +2658,7 @@ static struct dma_async_tx_descriptor *pl330_prep_dma_cyclic( desc->rqtype = direction; desc->rqcfg.brst_size = pch->burst_sz; - desc->rqcfg.brst_len = 1; + desc->rqcfg.brst_len = pch->burst_len; desc->bytes_requested = period_len; fill_px(&desc->px, dst, src, period_len); @@ -2741,7 +2803,7 @@ pl330_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, } desc->rqcfg.brst_size = pch->burst_sz; - desc->rqcfg.brst_len = 1; + desc->rqcfg.brst_len = pch->burst_len; desc->rqtype = direction; desc->bytes_requested = sg_dma_len(sg); } -- 2.11.0
