[PATCH 5.15 203/570] mmc: sdhci-pci-gli: fix GL9750 DMA write corruption

Greg Kroah-Hartman
2026-04-13T16:26:47Z

From: Matthew Schwartz <matthew.schwartz@linux.dev>

commit 2b76e0cc7803e5ab561c875edaba7f6bbd87fbb0 upstream.

The GL9750 SD host controller has intermittent data corruption during
DMA write operations. The GM_BURST register's R_OSRC_Lmt field
(bits 17:16), which limits outstanding DMA read requests from system
memory, is not being cleared during initialization. The Windows driver
sets R_OSRC_Lmt to zero, limiting requests to the smallest unit.

Clear R_OSRC_Lmt to match the Windows driver behavior. This eliminates
write corruption verified with f3write/f3read tests while maintaining
DMA performance.

Cc: stable@vger.kernel.org
Fixes: e51df6ce668a ("mmc: host: sdhci-pci: Add Genesys Logic GL975x support")
Closes: https://lore.kernel.org/linux-mmc/33d12807-5c72-41ce-8679-57aa11831fad@linux.dev/
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Matthew Schwartz <matthew.schwartz@linux.dev>
Reviewed-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/mmc/host/sdhci-pci-gli.c | 9 +++++++++
1 file changed, 9 insertions(+)

--- a/drivers/mmc/host/sdhci-pci-gli.c
+++ b/drivers/mmc/host/sdhci-pci-gli.c
@@ -70,6 +70,9 @@
#define GLI_9750_MISC_RX_INV_VALUE GLI_9750_MISC_RX_INV_OFF
#define GLI_9750_MISC_TX1_DLY_VALUE 0x5

+#define SDHCI_GLI_9750_GM_BURST_SIZE 0x510
+#define SDHCI_GLI_9750_GM_BURST_SIZE_R_OSRC_LMT GENMASK(17, 16)
+
#define SDHCI_GLI_9750_TUNING_CONTROL 0x540
#define SDHCI_GLI_9750_TUNING_CONTROL_EN BIT(4)
#define GLI_9750_TUNING_CONTROL_EN_ON 0x1
@@ -188,10 +191,16 @@ static void gli_set_9750(struct sdhci_ho
u32 misc_value;
u32 parameter_value;
u32 control_value;
+ u32 burst_value;
u16 ctrl2;

gl9750_wt_on(host);

+ /* clear R_OSRC_Lmt to avoid DMA write corruption */
+ burst_value = sdhci_readl(host, SDHCI_GLI_9750_GM_BURST_SIZE);
+ burst_value &= ~SDHCI_GLI_9750_GM_BURST_SIZE_R_OSRC_LMT;
+ sdhci_writel(host, burst_value, SDHCI_GLI_9750_GM_BURST_SIZE);
+
driving_value = sdhci_readl(host, SDHCI_GLI_9750_DRIVING);
pll_value = sdhci_readl(host, SDHCI_GLI_9750_PLL);
sw_ctrl_value = sdhci_readl(host, SDHCI_GLI_9750_SW_CTRL);