Timing issue occurs on eMMC not only when modifying the frequency but also for all the switch command(CMD6). According to the MMC spec waiting 8 clocks after a switch command would be the thing to do.
This patch allows fixing CPU hang observed when trying to changing the bus width on a eMMC on SAMA5D4. Signed-off-by: Gregory CLEMENT <[email protected]> Tested-by: Marek Vasut <[email protected]> # on DENX MA5D4EV --- drivers/mmc/gen_atmel_mci.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/mmc/gen_atmel_mci.c b/drivers/mmc/gen_atmel_mci.c index da870c6..f090b27 100644 --- a/drivers/mmc/gen_atmel_mci.c +++ b/drivers/mmc/gen_atmel_mci.c @@ -36,6 +36,7 @@ struct atmel_mci_priv { struct mmc_config cfg; struct atmel_mci *mci; unsigned int initialized:1; + unsigned int curr_clk; }; /* Read Atmel MCI IP version */ @@ -91,7 +92,10 @@ static void mci_set_mode(struct mmc *mmc, u32 hz, u32 blklen) } } - + if (version >= 0x500) + priv->curr_clk = bus_hz / (clkdiv * 2 + clkodd + 2); + else + priv->curr_clk = (bus_hz / (clkdiv + 1)) / 2; blklen &= 0xfffc; mr = MMCI_BF(CLKDIV, clkdiv); @@ -118,8 +122,6 @@ static void mci_set_mode(struct mmc *mmc, u32 hz, u32 blklen) if (mmc->card_caps & mmc->cfg->host_caps & MMC_MODE_HS) writel(MMCI_BIT(HSMODE), &mci->cfg); - udelay(50); - priv->initialized = 1; } @@ -323,6 +325,13 @@ mci_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd, struct mmc_data *data) } } + /* + * After the switch command, wait for 8 clocks before the next + * command + */ + if (cmd->cmdidx == MMC_CMD_SWITCH) + udelay(8*1000000/ priv->curr_clk); /* 8 clk in us */ + return 0; } -- 2.5.0 _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
