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| author | Viresh Kumar <viresh.kumar@st.com> | 2011-04-18 14:54:56 +0530 |
|---|---|---|
| committer | Vinod Koul <vinod.koul@intel.com> | 2011-05-13 19:40:00 +0530 |
| commit | 69dc14b51c1aad9d82afd8f96bf4e4835089bffc (patch) | |
| tree | 494e852ee6531c5e91720246baf53623e45e4112 /drivers/dma | |
| parent | abf53902dcc6d44d2e06b09817fa67857aa686fe (diff) | |
| download | linux-69dc14b51c1aad9d82afd8f96bf4e4835089bffc.tar.bz2 | |
dmaengine/dw_dmac: Divide one sg to many desc, if sg len is greater than DWC_MAX_COUNT
If len passed in sg for slave_sg transfers is greater than DWC_MAX_COUNT, then
driver programmes controller incorrectly. This patch adds code to handle this
situation by allocation more than one desc for same sg.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/dw_dmac.c | 65 |
1 files changed, 44 insertions, 21 deletions
diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c index f209ff8835e8..a9755e3dd603 100644 --- a/drivers/dma/dw_dmac.c +++ b/drivers/dma/dw_dmac.c @@ -693,9 +693,15 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, reg = dws->tx_reg; for_each_sg(sgl, sg, sg_len, i) { struct dw_desc *desc; - u32 len; - u32 mem; + u32 len, dlen, mem; + mem = sg_phys(sg); + len = sg_dma_len(sg); + mem_width = 2; + if (unlikely(mem & 3 || len & 3)) + mem_width = 0; + +slave_sg_todev_fill_desc: desc = dwc_desc_get(dwc); if (!desc) { dev_err(chan2dev(chan), @@ -703,16 +709,19 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, goto err_desc_get; } - mem = sg_phys(sg); - len = sg_dma_len(sg); - mem_width = 2; - if (unlikely(mem & 3 || len & 3)) - mem_width = 0; - desc->lli.sar = mem; desc->lli.dar = reg; desc->lli.ctllo = ctllo | DWC_CTLL_SRC_WIDTH(mem_width); - desc->lli.ctlhi = len >> mem_width; + if ((len >> mem_width) > DWC_MAX_COUNT) { + dlen = DWC_MAX_COUNT << mem_width; + mem += dlen; + len -= dlen; + } else { + dlen = len; + len = 0; + } + + desc->lli.ctlhi = dlen >> mem_width; if (!first) { first = desc; @@ -726,7 +735,10 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, &first->tx_list); } prev = desc; - total_len += len; + total_len += dlen; + + if (len) + goto slave_sg_todev_fill_desc; } break; case DMA_FROM_DEVICE: @@ -739,15 +751,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, reg = dws->rx_reg; for_each_sg(sgl, sg, sg_len, i) { struct dw_desc *desc; - u32 len; - u32 mem; - - desc = dwc_desc_get(dwc); - if (!desc) { - dev_err(chan2dev(chan), - "not enough descriptors available\n"); - goto err_desc_get; - } + u32 len, dlen, mem; mem = sg_phys(sg); len = sg_dma_len(sg); @@ -755,10 +759,26 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, if (unlikely(mem & 3 || len & 3)) mem_width = 0; +slave_sg_fromdev_fill_desc: + desc = dwc_desc_get(dwc); + if (!desc) { + dev_err(chan2dev(chan), + "not enough descriptors available\n"); + goto err_desc_get; + } + desc->lli.sar = reg; desc->lli.dar = mem; desc->lli.ctllo = ctllo | DWC_CTLL_DST_WIDTH(mem_width); - desc->lli.ctlhi = len >> reg_width; + if ((len >> reg_width) > DWC_MAX_COUNT) { + dlen = DWC_MAX_COUNT << reg_width; + mem += dlen; + len -= dlen; + } else { + dlen = len; + len = 0; + } + desc->lli.ctlhi = dlen >> reg_width; if (!first) { first = desc; @@ -772,7 +792,10 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, &first->tx_list); } prev = desc; - total_len += len; + total_len += dlen; + + if (len) + goto slave_sg_fromdev_fill_desc; } break; default: |