From: Tony Lindgren <tony@atomide.com> To: Ulf Hansson <ulf.hansson@linaro.org> Cc: linux-mmc@vger.kernel.org, Kishon Vijay Abraham I <kishon@ti.com>, Peter Ujfalusi <peter.ujfalusi@ti.com>, Russell King <rmk+kernel@armlinux.org.uk>, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH] mmc: core: Lower max_seg_size if too high for DMA Date: Wed, 31 Oct 2018 08:57:38 -0700 [thread overview] Message-ID: <20181031155738.18367-1-tony@atomide.com> (raw) With CONFIG_DMA_API_DEBUG_SG a device may produce the following warning: "DMA-API: mapping sg segment longer than device claims to support" We default to 64KiB if a DMA engine driver does not initialize dma_parms and call dma_set_max_seg_size(). This may be lower that what many MMC drivers do with mmc->max_seg_size = mmc->max_blk_size * mmc->max_blk_count. Let's do a sanity check for max_seg_size being higher than what DMA supports in mmc_add_host() and lower it as needed. Cc: Kishon Vijay Abraham I <kishon@ti.com> Cc: Peter Ujfalusi <peter.ujfalusi@ti.com> Cc: Russell King <rmk+kernel@armlinux.org.uk> Reported-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Tony Lindgren <tony@atomide.com> --- drivers/mmc/core/host.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c --- a/drivers/mmc/core/host.c +++ b/drivers/mmc/core/host.c @@ -13,6 +13,7 @@ */ #include <linux/device.h> +#include <linux/dma-mapping.h> #include <linux/err.h> #include <linux/idr.h> #include <linux/of.h> @@ -415,6 +416,19 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev) EXPORT_SYMBOL(mmc_alloc_host); +static void mmc_check_max_seg_size(struct mmc_host *host) +{ + unsigned int max_seg_size = dma_get_max_seg_size(mmc_dev(host)); + + if (host->max_seg_size <= max_seg_size) + return; + + dev_info(mmc_dev(host), "Lowering max_seg_size for DMA: %u vs %u\n", + host->max_seg_size, max_seg_size); + + host->max_seg_size = max_seg_size; +} + /** * mmc_add_host - initialise host hardware * @host: mmc host @@ -430,6 +444,8 @@ int mmc_add_host(struct mmc_host *host) WARN_ON((host->caps & MMC_CAP_SDIO_IRQ) && !host->ops->enable_sdio_irq); + mmc_check_max_seg_size(host); + err = device_add(&host->class_dev); if (err) return err; -- 2.19.1
WARNING: multiple messages have this Message-ID (diff)
From: tony@atomide.com (Tony Lindgren) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] mmc: core: Lower max_seg_size if too high for DMA Date: Wed, 31 Oct 2018 08:57:38 -0700 [thread overview] Message-ID: <20181031155738.18367-1-tony@atomide.com> (raw) With CONFIG_DMA_API_DEBUG_SG a device may produce the following warning: "DMA-API: mapping sg segment longer than device claims to support" We default to 64KiB if a DMA engine driver does not initialize dma_parms and call dma_set_max_seg_size(). This may be lower that what many MMC drivers do with mmc->max_seg_size = mmc->max_blk_size * mmc->max_blk_count. Let's do a sanity check for max_seg_size being higher than what DMA supports in mmc_add_host() and lower it as needed. Cc: Kishon Vijay Abraham I <kishon@ti.com> Cc: Peter Ujfalusi <peter.ujfalusi@ti.com> Cc: Russell King <rmk+kernel@armlinux.org.uk> Reported-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Tony Lindgren <tony@atomide.com> --- drivers/mmc/core/host.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c --- a/drivers/mmc/core/host.c +++ b/drivers/mmc/core/host.c @@ -13,6 +13,7 @@ */ #include <linux/device.h> +#include <linux/dma-mapping.h> #include <linux/err.h> #include <linux/idr.h> #include <linux/of.h> @@ -415,6 +416,19 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev) EXPORT_SYMBOL(mmc_alloc_host); +static void mmc_check_max_seg_size(struct mmc_host *host) +{ + unsigned int max_seg_size = dma_get_max_seg_size(mmc_dev(host)); + + if (host->max_seg_size <= max_seg_size) + return; + + dev_info(mmc_dev(host), "Lowering max_seg_size for DMA: %u vs %u\n", + host->max_seg_size, max_seg_size); + + host->max_seg_size = max_seg_size; +} + /** * mmc_add_host - initialise host hardware * @host: mmc host @@ -430,6 +444,8 @@ int mmc_add_host(struct mmc_host *host) WARN_ON((host->caps & MMC_CAP_SDIO_IRQ) && !host->ops->enable_sdio_irq); + mmc_check_max_seg_size(host); + err = device_add(&host->class_dev); if (err) return err; -- 2.19.1
next reply other threads:[~2018-10-31 15:57 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-10-31 15:57 Tony Lindgren [this message] 2018-10-31 15:57 ` [PATCH] mmc: core: Lower max_seg_size if too high for DMA Tony Lindgren 2018-11-12 16:48 ` Peter Ujfalusi 2018-11-12 16:48 ` Peter Ujfalusi 2018-11-19 12:08 ` Ulf Hansson 2018-11-19 12:08 ` Ulf Hansson 2018-11-29 19:13 ` Tony Lindgren 2018-11-29 19:13 ` Tony Lindgren 2018-11-29 20:11 ` Ulf Hansson 2018-11-29 20:11 ` Ulf Hansson 2018-12-11 13:13 ` Russell King - ARM Linux 2018-12-11 13:13 ` Russell King - ARM Linux 2018-12-11 13:39 ` Ulf Hansson 2018-12-11 13:39 ` Ulf Hansson 2018-12-11 13:49 ` Russell King - ARM Linux 2018-12-11 13:49 ` Russell King - ARM Linux 2018-12-11 14:33 ` Peter Ujfalusi 2018-12-11 14:42 ` Russell King - ARM Linux 2018-12-11 14:42 ` Russell King - ARM Linux 2018-12-11 13:49 ` Peter Ujfalusi 2018-12-11 14:23 ` Tony Lindgren 2018-12-11 14:23 ` Tony Lindgren
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