@@ -664,12 +664,14 @@ static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
datactrl |= MCI_ST_DPSM_SDIOEN;
/*
- * The ST Micro variant for SDIO transfer sizes
- * less then 8 bytes should have clock H/W flow
- * control disabled.
+ * The ST Micro variant for SDIO small write transfers
+ * needs to have clock H/W flow control disabled,
+ * otherwise the transfer will not start. The threshold
+ * depends on the rate of MCLK.
*/
- if ((host->size < 8) &&
- (data->flags & MMC_DATA_WRITE))
+ if (data->flags & MMC_DATA_WRITE &&
+ (host->size < 8 ||
+ (host->size <= 8 && host->mclk > 50000000)))
clk = host->clk_reg & ~variant->clkreg_enable;
else
clk = host->clk_reg | variant->clkreg_enable;
For writes, HWFC shall be switched off when transfer size <= 8 bytes and when MCLK rate is above 50 MHz. For 50MHz and below it shall be switched off when transfer size < 8 bytes. Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> --- drivers/mmc/host/mmci.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)