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authorViresh Kumar <viresh.kumar@st.com>2011-04-18 14:54:56 +0530
committerVinod Koul <vinod.koul@intel.com>2011-05-13 19:40:00 +0530
commit69dc14b51c1aad9d82afd8f96bf4e4835089bffc (patch)
tree494e852ee6531c5e91720246baf53623e45e4112 /drivers/dma
parentabf53902dcc6d44d2e06b09817fa67857aa686fe (diff)
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.c65
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: