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dmaengine/amba-pl08x: Pass flow controller information with slave channel data

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At least, on SPEAr platforms there is one peripheral, JPEG, which can be flow
controller for DMA transfer. Currently DMA controller driver didn't support
peripheral flow controller configurations.

This patch adds device_fc field in struct pl08x_channel_data, which will be used
only for slave transfers and is not used in case of mem2mem transfers.

Signed-off-by: Viresh Kumar <[email protected]>
Acked-by: Linus Walleij <[email protected]>
Signed-off-by: Vinod Koul <[email protected]>
This commit is contained in:
Viresh Kumar 2011-08-05 15:32:42 +05:30 • committed by Vinod Koul
commit 0a2356572b
2 changed files with 57 additions and 8 deletions
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61
drivers/dma/amba-pl08x.c
View file

@ -66,11 +66,6 @@
* after the final transfer signalled by LBREQ or LSREQ. The DMAC
* will then move to the next LLI entry.
*
* Only the former works sanely with scatter lists, so we only implement
* the DMAC flow control method. However, peripherals which use the LBREQ
* and LSREQ signals (eg, MMCI) are unable to use this mode, which through
* these hardware restrictions prevents them from using scatter DMA.
*
* Global TODO:
* - Break out common code from arch/arm/mach-s3c64xx and share
*/
@ -617,6 +612,49 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
mbus == &bd.srcbus ? "src" : "dst",
sbus == &bd.srcbus ? "src" : "dst");
/*
* Zero length is only allowed if all these requirements are met:
* - flow controller is peripheral.
* - src.addr is aligned to src.width
* - dst.addr is aligned to dst.width
*
* sg_len == 1 should be true, as there can be two cases here:
* - Memory addresses are contiguous and are not scattered. Here, Only
* one sg will be passed by user driver, with memory address and zero
* length. We pass this to controller and after the transfer it will
* receive the last burst request from peripheral and so transfer
* finishes.
*
* - Memory addresses are scattered and are not contiguous. Here,
* Obviously as DMA controller doesn't know when a lli's transfer gets
* over, it can't load next lli. So in this case, there has to be an
* assumption that only one lli is supported. Thus, we can't have
* scattered addresses.
*/
if (!bd.remainder) {
u32 fc = (txd->ccfg & PL080_CONFIG_FLOW_CONTROL_MASK) >>
PL080_CONFIG_FLOW_CONTROL_SHIFT;
if (!((fc >= PL080_FLOW_SRC2DST_DST) &&
(fc <= PL080_FLOW_SRC2DST_SRC))) {
dev_err(&pl08x->adev->dev, "%s sg len can't be zero",
__func__);
return 0;
}
if ((bd.srcbus.addr % bd.srcbus.buswidth) ||
(bd.srcbus.addr % bd.srcbus.buswidth)) {
dev_err(&pl08x->adev->dev,
"%s src & dst address must be aligned to src"
" & dst width if peripheral is flow controller",
__func__);
return 0;
}
cctl = pl08x_cctl_bits(cctl, bd.srcbus.buswidth,
bd.dstbus.buswidth, 0);
pl08x_fill_lli_for_desc(&bd, num_llis++, 0, cctl);
}
/*
* Send byte by byte for following cases
* - Less than a bus width available
@ -1250,7 +1288,7 @@ static struct dma_async_tx_descriptor *pl08x_prep_slave_sg(
struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
struct pl08x_driver_data *pl08x = plchan->host;
struct pl08x_txd *txd;
int ret;
int ret, tmp;
/*
* Current implementation ASSUMES only one sg
@ -1284,12 +1322,10 @@ static struct dma_async_tx_descriptor *pl08x_prep_slave_sg(
txd->len = sgl->length;
if (direction == DMA_TO_DEVICE) {
txd->ccfg |= PL080_FLOW_MEM2PER << PL080_CONFIG_FLOW_CONTROL_SHIFT;
txd->cctl = plchan->dst_cctl;
txd->src_addr = sgl->dma_address;
txd->dst_addr = plchan->dst_addr;
} else if (direction == DMA_FROM_DEVICE) {
txd->ccfg |= PL080_FLOW_PER2MEM << PL080_CONFIG_FLOW_CONTROL_SHIFT;
txd->cctl = plchan->src_cctl;
txd->src_addr = plchan->src_addr;
txd->dst_addr = sgl->dma_address;
@ -1299,6 +1335,15 @@ static struct dma_async_tx_descriptor *pl08x_prep_slave_sg(
return NULL;
}
if (plchan->cd->device_fc)
tmp = (direction == DMA_TO_DEVICE) ? PL080_FLOW_MEM2PER_PER :
PL080_FLOW_PER2MEM_PER;
else
tmp = (direction == DMA_TO_DEVICE) ? PL080_FLOW_MEM2PER :
PL080_FLOW_PER2MEM;
txd->ccfg |= tmp << PL080_CONFIG_FLOW_CONTROL_SHIFT;
ret = pl08x_prep_channel_resources(plchan, txd);
if (ret)
return NULL;