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dmaengine: dw: fix byte order of hw descriptor fields
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If the DMA controller uses a different byte order than the host CPU,
the hardware linked list descriptor fields need to be byte-swapped.

This patch makes the driver write these fields using the same byte
order it uses for mmio accesses to the DMA engine. I do not know
if this is guaranteed to always be correct.

Signed-off-by: Mans Rullgard <[email protected]>
Acked-by: Andy Shevchenko <[email protected]>
Signed-off-by: Vinod Koul <[email protected]>
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@mansr
mansr authored and Vinod Koul committed Apr 13, 2016
1 parent bb3450a commit df1f3a2
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Showing 2 changed files with 87 additions and 68 deletions.
123 changes: 62 additions & 61 deletions drivers/dma/dw/core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -201,12 +201,12 @@ static inline void dwc_do_single_block(struct dw_dma_chan *dwc,
* Software emulation of LLP mode relies on interrupts to continue
* multi block transfer.
*/
ctllo = desc->lli.ctllo | DWC_CTLL_INT_EN;
ctllo = lli_read(desc, ctllo) | DWC_CTLL_INT_EN;

channel_writel(dwc, SAR, desc->lli.sar);
channel_writel(dwc, DAR, desc->lli.dar);
channel_writel(dwc, SAR, lli_read(desc, sar));
channel_writel(dwc, DAR, lli_read(desc, dar));
channel_writel(dwc, CTL_LO, ctllo);
channel_writel(dwc, CTL_HI, desc->lli.ctlhi);
channel_writel(dwc, CTL_HI, lli_read(desc, ctlhi));
channel_set_bit(dw, CH_EN, dwc->mask);

/* Move pointer to next descriptor */
Expand Down Expand Up @@ -424,7 +424,7 @@ static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
}

/* Check first descriptors llp */
if (desc->lli.llp == llp) {
if (lli_read(desc, llp) == llp) {
/* This one is currently in progress */
dwc->residue -= dwc_get_sent(dwc);
spin_unlock_irqrestore(&dwc->lock, flags);
Expand All @@ -433,7 +433,7 @@ static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)

dwc->residue -= desc->len;
list_for_each_entry(child, &desc->tx_list, desc_node) {
if (child->lli.llp == llp) {
if (lli_read(child, llp) == llp) {
/* Currently in progress */
dwc->residue -= dwc_get_sent(dwc);
spin_unlock_irqrestore(&dwc->lock, flags);
Expand Down Expand Up @@ -461,10 +461,14 @@ static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
spin_unlock_irqrestore(&dwc->lock, flags);
}

static inline void dwc_dump_lli(struct dw_dma_chan *dwc, struct dw_lli *lli)
static inline void dwc_dump_lli(struct dw_dma_chan *dwc, struct dw_desc *desc)
{
dev_crit(chan2dev(&dwc->chan), " desc: s0x%x d0x%x l0x%x c0x%x:%x\n",
lli->sar, lli->dar, lli->llp, lli->ctlhi, lli->ctllo);
lli_read(desc, sar),
lli_read(desc, dar),
lli_read(desc, llp),
lli_read(desc, ctlhi),
lli_read(desc, ctllo));
}

static void dwc_handle_error(struct dw_dma *dw, struct dw_dma_chan *dwc)
Expand Down Expand Up @@ -500,9 +504,9 @@ static void dwc_handle_error(struct dw_dma *dw, struct dw_dma_chan *dwc)
*/
dev_WARN(chan2dev(&dwc->chan), "Bad descriptor submitted for DMA!\n"
" cookie: %d\n", bad_desc->txd.cookie);
dwc_dump_lli(dwc, &bad_desc->lli);
dwc_dump_lli(dwc, bad_desc);
list_for_each_entry(child, &bad_desc->tx_list, desc_node)
dwc_dump_lli(dwc, &child->lli);
dwc_dump_lli(dwc, child);

spin_unlock_irqrestore(&dwc->lock, flags);

Expand Down Expand Up @@ -575,7 +579,7 @@ static void dwc_handle_cyclic(struct dw_dma *dw, struct dw_dma_chan *dwc,
dma_writel(dw, CLEAR.XFER, dwc->mask);

for (i = 0; i < dwc->cdesc->periods; i++)
dwc_dump_lli(dwc, &dwc->cdesc->desc[i]->lli);
dwc_dump_lli(dwc, dwc->cdesc->desc[i]);

spin_unlock_irqrestore(&dwc->lock, flags);
}
Expand Down Expand Up @@ -734,25 +738,24 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
if (!desc)
goto err_desc_get;

desc->lli.sar = src + offset;
desc->lli.dar = dest + offset;
desc->lli.ctllo = ctllo;
desc->lli.ctlhi = xfer_count;
lli_write(desc, sar, src + offset);
lli_write(desc, dar, dest + offset);
lli_write(desc, ctllo, ctllo);
lli_write(desc, ctlhi, xfer_count);
desc->len = xfer_count << src_width;

if (!first) {
first = desc;
} else {
prev->lli.llp = desc->txd.phys;
list_add_tail(&desc->desc_node,
&first->tx_list);
lli_write(prev, llp, desc->txd.phys);
list_add_tail(&desc->desc_node, &first->tx_list);
}
prev = desc;
}

if (flags & DMA_PREP_INTERRUPT)
/* Trigger interrupt after last block */
prev->lli.ctllo |= DWC_CTLL_INT_EN;
lli_set(prev, ctllo, DWC_CTLL_INT_EN);

prev->lli.llp = 0;
first->txd.flags = flags;
Expand Down Expand Up @@ -822,9 +825,9 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
if (!desc)
goto err_desc_get;

desc->lli.sar = mem;
desc->lli.dar = reg;
desc->lli.ctllo = ctllo | DWC_CTLL_SRC_WIDTH(mem_width);
lli_write(desc, sar, mem);
lli_write(desc, dar, reg);
lli_write(desc, ctllo, ctllo | DWC_CTLL_SRC_WIDTH(mem_width));
if ((len >> mem_width) > dwc->block_size) {
dlen = dwc->block_size << mem_width;
mem += dlen;
Expand All @@ -834,15 +837,14 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
len = 0;
}

desc->lli.ctlhi = dlen >> mem_width;
lli_write(desc, ctlhi, dlen >> mem_width);
desc->len = dlen;

if (!first) {
first = desc;
} else {
prev->lli.llp = desc->txd.phys;
list_add_tail(&desc->desc_node,
&first->tx_list);
lli_write(prev, llp, desc->txd.phys);
list_add_tail(&desc->desc_node, &first->tx_list);
}
prev = desc;
total_len += dlen;
Expand Down Expand Up @@ -879,9 +881,9 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
if (!desc)
goto err_desc_get;

desc->lli.sar = reg;
desc->lli.dar = mem;
desc->lli.ctllo = ctllo | DWC_CTLL_DST_WIDTH(mem_width);
lli_write(desc, sar, reg);
lli_write(desc, dar, mem);
lli_write(desc, ctllo, ctllo | DWC_CTLL_DST_WIDTH(mem_width));
if ((len >> reg_width) > dwc->block_size) {
dlen = dwc->block_size << reg_width;
mem += dlen;
Expand All @@ -890,15 +892,14 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
dlen = len;
len = 0;
}
desc->lli.ctlhi = dlen >> reg_width;
lli_write(desc, ctlhi, dlen >> reg_width);
desc->len = dlen;

if (!first) {
first = desc;
} else {
prev->lli.llp = desc->txd.phys;
list_add_tail(&desc->desc_node,
&first->tx_list);
lli_write(prev, llp, desc->txd.phys);
list_add_tail(&desc->desc_node, &first->tx_list);
}
prev = desc;
total_len += dlen;
Expand All @@ -913,7 +914,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,

if (flags & DMA_PREP_INTERRUPT)
/* Trigger interrupt after last block */
prev->lli.ctllo |= DWC_CTLL_INT_EN;
lli_set(prev, ctllo, DWC_CTLL_INT_EN);

prev->lli.llp = 0;
first->total_len = total_len;
Expand Down Expand Up @@ -1400,50 +1401,50 @@ struct dw_cyclic_desc *dw_dma_cyclic_prep(struct dma_chan *chan,

switch (direction) {
case DMA_MEM_TO_DEV:
desc->lli.dar = sconfig->dst_addr;
desc->lli.sar = buf_addr + (period_len * i);
desc->lli.ctllo = (DWC_DEFAULT_CTLLO(chan)
| DWC_CTLL_DST_WIDTH(reg_width)
| DWC_CTLL_SRC_WIDTH(reg_width)
| DWC_CTLL_DST_FIX
| DWC_CTLL_SRC_INC
| DWC_CTLL_INT_EN);

desc->lli.ctllo |= sconfig->device_fc ?
DWC_CTLL_FC(DW_DMA_FC_P_M2P) :
DWC_CTLL_FC(DW_DMA_FC_D_M2P);
lli_write(desc, dar, sconfig->dst_addr);
lli_write(desc, sar, buf_addr + period_len * i);
lli_write(desc, ctllo, (DWC_DEFAULT_CTLLO(chan)
| DWC_CTLL_DST_WIDTH(reg_width)
| DWC_CTLL_SRC_WIDTH(reg_width)
| DWC_CTLL_DST_FIX
| DWC_CTLL_SRC_INC
| DWC_CTLL_INT_EN));

lli_set(desc, ctllo, sconfig->device_fc ?
DWC_CTLL_FC(DW_DMA_FC_P_M2P) :
DWC_CTLL_FC(DW_DMA_FC_D_M2P));

break;
case DMA_DEV_TO_MEM:
desc->lli.dar = buf_addr + (period_len * i);
desc->lli.sar = sconfig->src_addr;
desc->lli.ctllo = (DWC_DEFAULT_CTLLO(chan)
| DWC_CTLL_SRC_WIDTH(reg_width)
| DWC_CTLL_DST_WIDTH(reg_width)
| DWC_CTLL_DST_INC
| DWC_CTLL_SRC_FIX
| DWC_CTLL_INT_EN);

desc->lli.ctllo |= sconfig->device_fc ?
DWC_CTLL_FC(DW_DMA_FC_P_P2M) :
DWC_CTLL_FC(DW_DMA_FC_D_P2M);
lli_write(desc, dar, buf_addr + period_len * i);
lli_write(desc, sar, sconfig->src_addr);
lli_write(desc, ctllo, (DWC_DEFAULT_CTLLO(chan)
| DWC_CTLL_SRC_WIDTH(reg_width)
| DWC_CTLL_DST_WIDTH(reg_width)
| DWC_CTLL_DST_INC
| DWC_CTLL_SRC_FIX
| DWC_CTLL_INT_EN));

lli_set(desc, ctllo, sconfig->device_fc ?
DWC_CTLL_FC(DW_DMA_FC_P_P2M) :
DWC_CTLL_FC(DW_DMA_FC_D_P2M));

break;
default:
break;
}

desc->lli.ctlhi = (period_len >> reg_width);
lli_write(desc, ctlhi, period_len >> reg_width);
cdesc->desc[i] = desc;

if (last)
last->lli.llp = desc->txd.phys;
lli_write(last, llp, desc->txd.phys);

last = desc;
}

/* Let's make a cyclic list */
last->lli.llp = cdesc->desc[0]->txd.phys;
lli_write(last, llp, cdesc->desc[0]->txd.phys);

dev_dbg(chan2dev(&dwc->chan),
"cyclic prepared buf %pad len %zu period %zu periods %d\n",
Expand Down
32 changes: 25 additions & 7 deletions drivers/dma/dw/regs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -308,26 +308,44 @@ static inline struct dw_dma *to_dw_dma(struct dma_device *ddev)
return container_of(ddev, struct dw_dma, dma);
}

#ifdef CONFIG_DW_DMAC_BIG_ENDIAN_IO
typedef __be32 __dw32;
#else
typedef __le32 __dw32;
#endif

/* LLI == Linked List Item; a.k.a. DMA block descriptor */
struct dw_lli {
/* values that are not changed by hardware */
u32 sar;
u32 dar;
u32 llp; /* chain to next lli */
u32 ctllo;
__dw32 sar;
__dw32 dar;
__dw32 llp; /* chain to next lli */
__dw32 ctllo;
/* values that may get written back: */
u32 ctlhi;
__dw32 ctlhi;
/* sstat and dstat can snapshot peripheral register state.
* silicon config may discard either or both...
*/
u32 sstat;
u32 dstat;
__dw32 sstat;
__dw32 dstat;
};

struct dw_desc {
/* FIRST values the hardware uses */
struct dw_lli lli;

#ifdef CONFIG_DW_DMAC_BIG_ENDIAN_IO
#define lli_set(d, reg, v) ((d)->lli.reg |= cpu_to_be32(v))
#define lli_clear(d, reg, v) ((d)->lli.reg &= ~cpu_to_be32(v))
#define lli_read(d, reg) be32_to_cpu((d)->lli.reg)
#define lli_write(d, reg, v) ((d)->lli.reg = cpu_to_be32(v))
#else
#define lli_set(d, reg, v) ((d)->lli.reg |= cpu_to_le32(v))
#define lli_clear(d, reg, v) ((d)->lli.reg &= ~cpu_to_le32(v))
#define lli_read(d, reg) le32_to_cpu((d)->lli.reg)
#define lli_write(d, reg, v) ((d)->lli.reg = cpu_to_le32(v))
#endif

/* THEN values for driver housekeeping */
struct list_head desc_node;
struct list_head tx_list;
Expand Down

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