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authorDmitry Osipenko <digetx@gmail.com>2017-11-16 20:11:06 +0300
committerVinod Koul <vinod.koul@intel.com>2017-11-29 17:05:05 +0300
commitf6160f359846408056c2646f1dbb4ea098930fee (patch)
treea38c94208363cf0177df714a1a84f5ae83c7285b
parent4fbd8d194f06c8a3fd2af1ce560ddb31f7ec8323 (diff)
downloadlinux-f6160f359846408056c2646f1dbb4ea098930fee.tar.xz
dmaengine: tegra-apb: Support non-flow controlled slave configuration
This allows DMA client to issue a non-flow controlled TX. In particular it is needed for the fuse driver that reads fuse registers using APBDMA to workaround a HW bug that results in hang when CPU and DMA perform simultaneous access to fuse peripheral. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Reviewed-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
-rw-r--r--drivers/dma/tegra20-apb-dma.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index b9d75a54c896..9a558e30c461 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -353,7 +353,8 @@ static int tegra_dma_slave_config(struct dma_chan *dc,
}
memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig));
- if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID) {
+ if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID &&
+ sconfig->device_fc) {
if (sconfig->slave_id > TEGRA_APBDMA_CSR_REQ_SEL_MASK)
return -EINVAL;
tdc->slave_id = sconfig->slave_id;
@@ -970,8 +971,13 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg(
TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;
ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
- csr |= TEGRA_APBDMA_CSR_ONCE | TEGRA_APBDMA_CSR_FLOW;
- csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
+ csr |= TEGRA_APBDMA_CSR_ONCE;
+
+ if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {
+ csr |= TEGRA_APBDMA_CSR_FLOW;
+ csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
+ }
+
if (flags & DMA_PREP_INTERRUPT)
csr |= TEGRA_APBDMA_CSR_IE_EOC;
@@ -1110,10 +1116,13 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;
ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
- csr |= TEGRA_APBDMA_CSR_FLOW;
+ if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {
+ csr |= TEGRA_APBDMA_CSR_FLOW;
+ csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
+ }
+
if (flags & DMA_PREP_INTERRUPT)
csr |= TEGRA_APBDMA_CSR_IE_EOC;
- csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;