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spi: respect the maximum segment size of DMA device

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The device which is actually does DMA may have a limitation of the maximum
segment size. Respect this setting when preparing scatter-gather list.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Andy Shevchenko 2016-03-09 11:20:00 +02:00 committed by Mark Brown
parent 92e963f50f
commit df88e91bbf
1 changed files with 3 additions and 3 deletions
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6
drivers/spi/spi.c
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@ -702,6 +702,7 @@ static int spi_map_buf(struct spi_master *master, struct device *dev,
enum dma_data_direction dir)
{
const bool vmalloced_buf = is_vmalloc_addr(buf);
unsigned int max_seg_size = dma_get_max_seg_size(dev);
int desc_len;
int sgs;
struct page *vm_page;
@ -710,10 +711,10 @@ static int spi_map_buf(struct spi_master *master, struct device *dev,
int i, ret;
if (vmalloced_buf) {
desc_len = PAGE_SIZE;
desc_len = min_t(int, max_seg_size, PAGE_SIZE);
sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
} else {
desc_len = master->max_dma_len;
desc_len = min_t(int, max_seg_size, master->max_dma_len);
sgs = DIV_ROUND_UP(len, desc_len);
}
@ -739,7 +740,6 @@ static int spi_map_buf(struct spi_master *master, struct device *dev,
sg_set_buf(&sgt->sgl[i], sg_buf, min);
}
buf += min;
len -= min;
}