When building with a 64-bit dma_addr_t, we run into a link
error:
drivers/dma/stm32-mdma.o: In function `stm32_mdma_prep_dma_memcpy':
stm32-mdma.c:(.text+0x16a3): undefined reference to `__umoddi3'
Using a 64-bit division here is way too expensive, since the
divisor is a known power-of-two value in reality. This moves
the modulo operation into stm32_mdma_get_max_width(), where
the compiler can optimize out that code, and we can use a 32-bit
division to be on the safe side.
Fixes: a4ffb13c8946 ("dmaengine: Add STM32 MDMA driver")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/dma/stm32-mdma.c | 27 ++++++++++++---------------
1 file changed, 12 insertions(+), 15 deletions(-)
diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
index 0db59a7e80e0..55151c2c9fae 100644
--- a/drivers/dma/stm32-mdma.c
+++ b/drivers/dma/stm32-mdma.c
@@ -387,7 +387,9 @@ 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(u32 buf_len,
+ u32 addr,
+ u32 tlen)
{
enum dma_slave_buswidth max_width = DMA_SLAVE_BUSWIDTH_8_BYTES;
@@ -398,6 +400,9 @@ static enum dma_slave_buswidth stm32_mdma_get_max_width(u32 buf_len, u32 tlen)
break;
}
+ if (addr % max_width)
+ max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+
return max_width;
}
@@ -567,7 +572,7 @@ 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(buf_len, 0, tlen);
chan->mem_width = src_addr_width;
src_bus_width = stm32_mdma_get_width(chan, src_addr_width);
if (src_bus_width < 0)
@@ -611,7 +616,7 @@ 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(buf_len, 0, tlen);
chan->mem_width = dst_addr_width;
dst_bus_width = stm32_mdma_get_width(chan, dst_addr_width);
if (dst_bus_width < 0)
@@ -956,9 +961,7 @@ 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(len, src, tlen);
src_bus_width = stm32_mdma_get_width(chan, max_width);
max_burst = tlen / max_width;
@@ -971,9 +974,7 @@ 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(len, dest, tlen);
dst_bus_width = stm32_mdma_get_width(chan, max_width);
max_burst = tlen / max_width;
@@ -1014,9 +1015,7 @@ 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(len, src, tlen);
src_bus_width = stm32_mdma_get_width(chan, max_width);
max_burst = tlen / max_width;
@@ -1030,9 +1029,7 @@ 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(len, dest, tlen);
dst_bus_width = stm32_mdma_get_width(chan, max_width);
max_burst = tlen / max_width;
--
2.9.0
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