From a5c4aa9ca53defd609efdaaff623624d236c67b8 Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 11 Dec 2018 14:41:31 +0000 Subject: mmc: omap_hsmmc: fix DMA API warning commit 0b479790684192ab7024ce6a621f93f6d0a64d92 upstream. While booting with rootfs on MMC, the following warning is encountered on OMAP4430: omap-dma-engine 4a056000.dma-controller: DMA-API: mapping sg segment longer than device claims to support [len=69632] [max=65536] This is because the DMA engine has a default maximum segment size of 64K but HSMMC sets: mmc->max_blk_size = 512; /* Block Length at max can be 1024 */ mmc->max_blk_count = 0xFFFF; /* No. of Blocks is 16 bits */ mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count; mmc->max_seg_size = mmc->max_req_size; which ends up telling the block layer that we support a maximum segment size of 65535*512, which exceeds the advertised DMA engine capabilities. Fix this by clamping the maximum segment size to the lower of the maximum request size and of the DMA engine device used for either DMA channel. Signed-off-by: Russell King Cc: Signed-off-by: Ulf Hansson Signed-off-by: Greg Kroah-Hartman --- drivers/mmc/host/omap_hsmmc.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'drivers/mmc/host/omap_hsmmc.c') diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c index 6b814d7d6560..af937d3e8c3e 100644 --- a/drivers/mmc/host/omap_hsmmc.c +++ b/drivers/mmc/host/omap_hsmmc.c @@ -2117,7 +2117,6 @@ static int omap_hsmmc_probe(struct platform_device *pdev) mmc->max_blk_size = 512; /* Block Length at max can be 1024 */ mmc->max_blk_count = 0xFFFF; /* No. of Blocks is 16 bits */ mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count; - mmc->max_seg_size = mmc->max_req_size; mmc->caps |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED | MMC_CAP_WAIT_WHILE_BUSY | MMC_CAP_ERASE; @@ -2174,6 +2173,17 @@ static int omap_hsmmc_probe(struct platform_device *pdev) goto err_irq; } + /* + * Limit the maximum segment size to the lower of the request size + * and the DMA engine device segment size limits. In reality, with + * 32-bit transfers, the DMA engine can do longer segments than this + * but there is no way to represent that in the DMA model - if we + * increase this figure here, we get warnings from the DMA API debug. + */ + mmc->max_seg_size = min3(mmc->max_req_size, + dma_get_max_seg_size(host->rx_chan->device->dev), + dma_get_max_seg_size(host->tx_chan->device->dev)); + /* Request IRQ for MMC operations */ ret = devm_request_irq(&pdev->dev, host->irq, omap_hsmmc_irq, 0, mmc_hostname(mmc), host); -- cgit v1.2.3