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Subject[PATCH v1] dmaengine: stm32_mdma: activate pack/unpack feature
Date
If source and destination bus width differs pack/unpack MDMA
feature has to be activated for alignment.
This pack/unpack feature implies to have both source/destination address
and buffer length aligned on bus width.

Fixes: a4ffb13c8946 ("dmaengine: Add STM32 MDMA driver")
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
---
drivers/dma/stm32-mdma.c | 84 ++++++++++++++++++++++++++++--------------------
1 file changed, 50 insertions(+), 34 deletions(-)

diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
index d3be6bf..daa1602 100644
--- a/drivers/dma/stm32-mdma.c
+++ b/drivers/dma/stm32-mdma.c
@@ -387,14 +387,20 @@ static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
}
}

-static enum dma_slave_buswidth stm32_mdma_get_max_width(u32 buf_len, u32 tlen)
+static enum dma_slave_buswidth stm32_mdma_get_max_width(dma_addr_t addr,
+ u32 buf_len, u32 tlen)
{
enum dma_slave_buswidth max_width = DMA_SLAVE_BUSWIDTH_8_BYTES;

for (max_width = DMA_SLAVE_BUSWIDTH_8_BYTES;
max_width > DMA_SLAVE_BUSWIDTH_1_BYTE;
max_width >>= 1) {
- if (((buf_len % max_width) == 0) && (tlen >= max_width))
+ /*
+ * Address and buffer length both have to be aligned on
+ * bus width
+ */
+ if ((((buf_len | addr) & (max_width - 1)) == 0) &&
+ tlen >= max_width)
break;
}

@@ -486,7 +492,8 @@ static void stm32_mdma_set_bus(struct stm32_mdma_device *dmadev, u32 *ctbr,
static int stm32_mdma_set_xfer_param(struct stm32_mdma_chan *chan,
enum dma_transfer_direction direction,
u32 *mdma_ccr, u32 *mdma_ctcr,
- u32 *mdma_ctbr, u32 buf_len)
+ u32 *mdma_ctbr, dma_addr_t addr,
+ u32 buf_len)
{
struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
struct stm32_mdma_chan_config *chan_config = &chan->chan_config;
@@ -520,6 +527,9 @@ static int stm32_mdma_set_xfer_param(struct stm32_mdma_chan *chan,
ctcr &= ~STM32_MDMA_CTCR_LEN2_MSK;
ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));

+ /* Disable Pack Enable */
+ ctcr &= ~STM32_MDMA_CTCR_PKE;
+
/* Check burst size constraints */
if (src_maxburst * src_addr_width > STM32_MDMA_MAX_BURST ||
dst_maxburst * dst_addr_width > STM32_MDMA_MAX_BURST) {
@@ -551,6 +561,8 @@ static int stm32_mdma_set_xfer_param(struct stm32_mdma_chan *chan,

switch (direction) {
case DMA_MEM_TO_DEV:
+ dst_addr = chan->dma_config.dst_addr;
+
/* Set device data size */
dst_bus_width = stm32_mdma_get_width(chan, dst_addr_width);
if (dst_bus_width < 0)
@@ -567,7 +579,7 @@ static int stm32_mdma_set_xfer_param(struct stm32_mdma_chan *chan,
ctcr |= STM32_MDMA_CTCR_DBURST((ilog2(dst_best_burst)));

/* Set memory data size */
- src_addr_width = stm32_mdma_get_max_width(buf_len, tlen);
+ src_addr_width = stm32_mdma_get_max_width(addr, buf_len, tlen);
chan->mem_width = src_addr_width;
src_bus_width = stm32_mdma_get_width(chan, src_addr_width);
if (src_bus_width < 0)
@@ -587,15 +599,19 @@ static int stm32_mdma_set_xfer_param(struct stm32_mdma_chan *chan,
ctcr |= STM32_MDMA_CTCR_SBURST((ilog2(src_best_burst)));

/* Select bus */
- dst_addr = chan->dma_config.dst_addr;
stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS,
dst_addr);

+ if (dst_bus_width != src_bus_width)
+ ctcr |= STM32_MDMA_CTCR_PKE;
+
/* Set destination address */
stm32_mdma_write(dmadev, STM32_MDMA_CDAR(chan->id), dst_addr);
break;

case DMA_DEV_TO_MEM:
+ src_addr = chan->dma_config.src_addr;
+
/* Set device data size */
src_bus_width = stm32_mdma_get_width(chan, src_addr_width);
if (src_bus_width < 0)
@@ -611,7 +627,7 @@ static int stm32_mdma_set_xfer_param(struct stm32_mdma_chan *chan,
ctcr |= STM32_MDMA_CTCR_SBURST((ilog2(src_best_burst)));

/* Set memory data size */
- dst_addr_width = stm32_mdma_get_max_width(buf_len, tlen);
+ dst_addr_width = stm32_mdma_get_max_width(addr, buf_len, tlen);
chan->mem_width = dst_addr_width;
dst_bus_width = stm32_mdma_get_width(chan, dst_addr_width);
if (dst_bus_width < 0)
@@ -630,10 +646,12 @@ static int stm32_mdma_set_xfer_param(struct stm32_mdma_chan *chan,
ctcr |= STM32_MDMA_CTCR_DBURST((ilog2(dst_best_burst)));

/* Select bus */
- src_addr = chan->dma_config.src_addr;
stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS,
src_addr);

+ if (dst_bus_width != src_bus_width)
+ ctcr |= STM32_MDMA_CTCR_PKE;
+
/* Set source address */
stm32_mdma_write(dmadev, STM32_MDMA_CSAR(chan->id), src_addr);
break;
@@ -719,23 +737,27 @@ static int stm32_mdma_setup_xfer(struct stm32_mdma_chan *chan,
return -EINVAL;
}

- ret = stm32_mdma_set_xfer_param(chan, direction, &ccr, &ctcr,
- &ctbr, sg_dma_len(sg));
- if (ret < 0)
- return ret;
-
if (direction == DMA_MEM_TO_DEV) {
src_addr = sg_dma_address(sg);
dst_addr = dma_config->dst_addr;
+ ret = stm32_mdma_set_xfer_param(chan, direction, &ccr,
+ &ctcr, &ctbr, src_addr,
+ sg_dma_len(sg));
stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS,
src_addr);
} else {
src_addr = dma_config->src_addr;
dst_addr = sg_dma_address(sg);
+ ret = stm32_mdma_set_xfer_param(chan, direction, &ccr,
+ &ctcr, &ctbr, dst_addr,
+ sg_dma_len(sg));
stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS,
dst_addr);
}

+ if (ret < 0)
+ return ret;
+
stm32_mdma_setup_hwdesc(chan, desc, direction, i, src_addr,
dst_addr, sg_dma_len(sg), ctcr, ctbr,
i == sg_len - 1, i == 0, false);
@@ -830,27 +852,29 @@ stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
if (!desc)
return NULL;

- ret = stm32_mdma_set_xfer_param(chan, direction, &ccr, &ctcr, &ctbr,
- period_len);
- if (ret < 0)
- goto xfer_setup_err;
-
- /* Enable interrupts */
- ccr &= ~STM32_MDMA_CCR_IRQ_MASK;
- ccr |= STM32_MDMA_CCR_TEIE | STM32_MDMA_CCR_CTCIE | STM32_MDMA_CCR_BTIE;
- desc->ccr = ccr;
-
/* Select bus */
if (direction == DMA_MEM_TO_DEV) {
src_addr = buf_addr;
+ ret = stm32_mdma_set_xfer_param(chan, direction, &ccr, &ctcr,
+ &ctbr, src_addr, period_len);
stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS,
src_addr);
} else {
dst_addr = buf_addr;
+ ret = stm32_mdma_set_xfer_param(chan, direction, &ccr, &ctcr,
+ &ctbr, dst_addr, period_len);
stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS,
dst_addr);
}

+ if (ret < 0)
+ goto xfer_setup_err;
+
+ /* Enable interrupts */
+ ccr &= ~STM32_MDMA_CCR_IRQ_MASK;
+ ccr |= STM32_MDMA_CCR_TEIE | STM32_MDMA_CCR_CTCIE | STM32_MDMA_CCR_BTIE;
+ desc->ccr = ccr;
+
/* Configure hwdesc list */
for (i = 0; i < count; i++) {
if (direction == DMA_MEM_TO_DEV) {
@@ -956,9 +980,7 @@ stm32_mdma_prep_dma_memcpy(struct dma_chan *c, dma_addr_t dest, dma_addr_t src,
ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));

/* Set source best burst size */
- max_width = stm32_mdma_get_max_width(len, tlen);
- if (src % max_width)
- max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ max_width = stm32_mdma_get_max_width(src, len, tlen);
src_bus_width = stm32_mdma_get_width(chan, max_width);

max_burst = tlen / max_width;
@@ -971,9 +993,7 @@ stm32_mdma_prep_dma_memcpy(struct dma_chan *c, dma_addr_t dest, dma_addr_t src,
STM32_MDMA_CTCR_SINCOS(src_bus_width);

/* Set destination best burst size */
- max_width = stm32_mdma_get_max_width(len, tlen);
- if (dest % max_width)
- max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ max_width = stm32_mdma_get_max_width(dest, len, tlen);
dst_bus_width = stm32_mdma_get_width(chan, max_width);

max_burst = tlen / max_width;
@@ -1014,9 +1034,7 @@ stm32_mdma_prep_dma_memcpy(struct dma_chan *c, dma_addr_t dest, dma_addr_t src,
STM32_MDMA_MAX_BLOCK_LEN);

/* Set source best burst size */
- max_width = stm32_mdma_get_max_width(len, tlen);
- if (src % max_width)
- max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ max_width = stm32_mdma_get_max_width(src, len, tlen);
src_bus_width = stm32_mdma_get_width(chan, max_width);

max_burst = tlen / max_width;
@@ -1030,9 +1048,7 @@ stm32_mdma_prep_dma_memcpy(struct dma_chan *c, dma_addr_t dest, dma_addr_t src,
STM32_MDMA_CTCR_SINCOS(src_bus_width);

/* Set destination best burst size */
- max_width = stm32_mdma_get_max_width(len, tlen);
- if (dest % max_width)
- max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ max_width = stm32_mdma_get_max_width(dest, len, tlen);
dst_bus_width = stm32_mdma_get_width(chan, max_width);

max_burst = tlen / max_width;
--
2.7.4
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