| Message ID | 20180921085948.26975-2-heiko@sntech.de |
|---|---|
| State | Accepted |
| Commit | 05fa06b9606387ad4a65723d93a83b36a98d600b |
| Delegated to: | Philipp Tomsich |
| Headers | show |
| Series | rockchip: allow rk3188 to boot from mmc devices | expand |
> On 21.09.2018, at 10:59, Heiko Stuebner <heiko@sntech.de> wrote: > > While trying to enable the dw_mmc on rk3188 I managed to confuse > and hang the dw_mmc controller into not delivering further data. > The fifo state never became ready and the driver was iterating in > the while loop reading 0-byte packets forever. > > So inspired by how other implementations handle this, check the fifo- > state beforhand and add a timeout to catch any glaring fifo issues > without hanging uboot altogether. > > Signed-off-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com> Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
> While trying to enable the dw_mmc on rk3188 I managed to confuse > and hang the dw_mmc controller into not delivering further data. > The fifo state never became ready and the driver was iterating in > the while loop reading 0-byte packets forever. > > So inspired by how other implementations handle this, check the fifo- > state beforhand and add a timeout to catch any glaring fifo issues > without hanging uboot altogether. > > Signed-off-by: Heiko Stuebner <heiko@sntech.de> > Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com> > Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com> > --- > drivers/mmc/dw_mmc.c | 32 ++++++++++++++++++++++++++++++-- > include/dwmmc.h | 2 ++ > 2 files changed, 32 insertions(+), 2 deletions(-) > Applied to u-boot-rockchip, thanks!
diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c index 13180fc0d6..3c702b3ed8 100644 --- a/drivers/mmc/dw_mmc.c +++ b/drivers/mmc/dw_mmc.c @@ -92,6 +92,24 @@ static void dwmci_prepare_data(struct dwmci_host *host, dwmci_writel(host, DWMCI_BYTCNT, data->blocksize * data->blocks); } +static int dwmci_fifo_ready(struct dwmci_host *host, u32 bit, u32 *len) +{ + u32 timeout = 20000; + + *len = dwmci_readl(host, DWMCI_STATUS); + while (--timeout && (*len & bit)) { + udelay(200); + *len = dwmci_readl(host, DWMCI_STATUS); + } + + if (!timeout) { + debug("%s: FIFO underflow timeout\n", __func__); + return -ETIMEDOUT; + } + + return 0; +} + static int dwmci_data_transfer(struct dwmci_host *host, struct mmc_data *data) { int ret = 0; @@ -122,7 +140,12 @@ static int dwmci_data_transfer(struct dwmci_host *host, struct mmc_data *data) if (data->flags == MMC_DATA_READ && (mask & DWMCI_INTMSK_RXDR)) { while (size) { - len = dwmci_readl(host, DWMCI_STATUS); + ret = dwmci_fifo_ready(host, + DWMCI_FIFO_EMPTY, + &len); + if (ret < 0) + break; + len = (len >> DWMCI_FIFO_SHIFT) & DWMCI_FIFO_MASK; len = min(size, len); @@ -136,7 +159,12 @@ static int dwmci_data_transfer(struct dwmci_host *host, struct mmc_data *data) } else if (data->flags == MMC_DATA_WRITE && (mask & DWMCI_INTMSK_TXDR)) { while (size) { - len = dwmci_readl(host, DWMCI_STATUS); + ret = dwmci_fifo_ready(host, + DWMCI_FIFO_FULL, + &len); + if (ret < 0) + break; + len = fifo_depth - ((len >> DWMCI_FIFO_SHIFT) & DWMCI_FIFO_MASK); diff --git a/include/dwmmc.h b/include/dwmmc.h index bc1d6e3abb..0f9d51b557 100644 --- a/include/dwmmc.h +++ b/include/dwmmc.h @@ -103,6 +103,8 @@ #define DWMCI_CTYPE_8BIT (1 << 16) /* Status Register */ +#define DWMCI_FIFO_EMPTY (1 << 2) +#define DWMCI_FIFO_FULL (1 << 3) #define DWMCI_BUSY (1 << 9) #define DWMCI_FIFO_MASK 0x1fff #define DWMCI_FIFO_SHIFT 17
While trying to enable the dw_mmc on rk3188 I managed to confuse and hang the dw_mmc controller into not delivering further data. The fifo state never became ready and the driver was iterating in the while loop reading 0-byte packets forever. So inspired by how other implementations handle this, check the fifo- state beforhand and add a timeout to catch any glaring fifo issues without hanging uboot altogether. Signed-off-by: Heiko Stuebner <heiko@sntech.de> --- drivers/mmc/dw_mmc.c | 32 ++++++++++++++++++++++++++++++-- include/dwmmc.h | 2 ++ 2 files changed, 32 insertions(+), 2 deletions(-)