The commit 0252924ac6d4 ("mmc: dw_mmc: Extract FIFO data transfer into a separate routine") unintentionally changed behavior of the FIFO data transfer routine.

When data is read and size reaches 0 the original loop would wait on DWMCI_INTMSK_DTO or timeout. The remaining size to read is no longer tracked across dwmci_data_transfer_fifo() calls and because of this an extra call to fifo() and dwmci_fifo_ready() may now trigger a FIFO underflow timeout.

Buswidth = 4, clock: 50000000 Sending CMD16 Sending CMD17 dwmci_fifo_ready: FIFO underflow timeout Sending CMD16 Sending CMD18 dwmci_fifo_ready: FIFO underflow timeout Sending CMD12 ## Checking hash(es) for config config-1 ... OK

Restore old behavior and track remaining size to read across calls to fix this.

Fixes: 0252924ac6d4 ("mmc: dw_mmc: Extract FIFO data transfer into a separate routine") Signed-off-by: Jonas Karlman jonas@kwiboo.se --- Reading FIT from SD-card take ~20-30 seconds on a Rockchip RK3328 board without this fixed, and goes back to sub second once fixed. --- drivers/mmc/dw_mmc.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c index 8551eac70185..98b85fd1795a 100644 --- a/drivers/mmc/dw_mmc.c +++ b/drivers/mmc/dw_mmc.c @@ -214,16 +214,15 @@ static unsigned int dwmci_get_timeout(struct mmc *mmc, const unsigned int size) return timeout; }

-static int dwmci_data_transfer_fifo(struct dwmci_host *host, - struct mmc_data *data, u32 mask) +static u32 dwmci_data_transfer_fifo(struct dwmci_host *host, + struct mmc_data *data, u32 size, u32 mask) { const u32 int_rx = mask & (DWMCI_INTMSK_RXDR | DWMCI_INTMSK_DTO); const u32 int_tx = mask & DWMCI_INTMSK_TXDR; int ret = 0; - u32 len = 0, size, i; + u32 len = 0, i; u32 *buf;

- size = (data->blocksize * data->blocks) / 4; if (!host->fifo_mode || !size) return 0;

@@ -261,7 +260,7 @@ static int dwmci_data_transfer_fifo(struct dwmci_host *host, dwmci_writel(host, DWMCI_RINTSTS, DWMCI_INTMSK_TXDR); }

- return ret; + return size; }

static int dwmci_data_transfer(struct dwmci_host *host, struct mmc_data *data) @@ -273,6 +272,7 @@ static int dwmci_data_transfer(struct dwmci_host *host, struct mmc_data *data)

size = data->blocksize * data->blocks; timeout = dwmci_get_timeout(mmc, size); + size /= 4;

for (;;) { mask = dwmci_readl(host, DWMCI_RINTSTS); @@ -283,7 +283,7 @@ static int dwmci_data_transfer(struct dwmci_host *host, struct mmc_data *data) break; }

- ret = dwmci_data_transfer_fifo(host, data, mask); + size = dwmci_data_transfer_fifo(host, data, size, mask);

/* Data arrived correctly */ if (mask & DWMCI_INTMSK_DTO) {