From: Andy Shevchenko Date: Wed, 9 Mar 2016 09:20:00 +0000 (+0200) Subject: spi: respect the maximum segment size of DMA device X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=df88e91bbfd16662f3c8dcba27ad19e9eb4ebcef;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git spi: respect the maximum segment size of DMA device 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 Signed-off-by: Mark Brown --- diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 47eff8012a77..9e6480a2e869 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -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; }