[PATCH 3/3] mmc: sdhci: Set DMA maximum segment size to 64 KiB

[Thierry Reding <thierry.reding@gmail.com>]

From: Thierry Reding <treding@nvidia.com>

DMA descriptors used with SDHCI have a 16-bit field that specifies the
number of bytes to transfer per segment. A segment's size may therefore
never exceed 64 KiB.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/mmc/host/sdhci.c | 5 +++++
 drivers/mmc/host/sdhci.h | 1 +
 2 files changed, 6 insertions(+)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index d814dc004bad..b59d063646bf 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -3555,6 +3555,10 @@ struct sdhci_host *sdhci_alloc_host(struct device *dev,
 	 */
 	host->adma_table_cnt = SDHCI_MAX_SEGS * 2 + 1;
 
+	/* ADMA supports a maximum of 64 KiB per descriptor */
+	dev->dma_parms = &host->dma_params;
+	dma_set_max_seg_size(dev, SZ_64K);
+
 	return host;
 }
 
@@ -4410,6 +4414,7 @@ EXPORT_SYMBOL_GPL(sdhci_remove_host);
 
 void sdhci_free_host(struct sdhci_host *host)
 {
+	host->mmc->parent->dma_parms = NULL;
 	mmc_free_host(host->mmc);
 }
 
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index cf3d1ed91909..b543d31bbcdb 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -494,6 +494,7 @@ struct sdhci_host {
 	/* Internal data */
 	struct mmc_host *mmc;	/* MMC structure */
 	struct mmc_host_ops mmc_host_ops;	/* MMC host ops */
+	struct device_dma_parameters dma_params; /* DMA parameters */
 	u64 dma_mask;		/* custom DMA mask */
 
 #if IS_ENABLED(CONFIG_LEDS_CLASS)
-- 
2.23.0