On Tuesday, August 28, 2012, Jaehoon Chung <[email protected]> wrote:
> synopsys spec is mentioned. (7.1 Software/Hardware Restrictions)
> "Before disabling clock, ensure that card is not busy due to any previous
> data command."
>
> At specific board, i found the problem that didn't inform ciu.
> (It didn't produce always.)
> At that time, i checked the status register whether card is busy or not.
> (Start bit of CMD register is cleared, but card is busy.)
> Current code didn't check the card status. Just check whether the start-bit
> cleared.
> host regard that command is completed, will send the next command.
> But next command didn't issue because Card is busy.
> This patch can prevent this situation.
>
> Signed-off-by: Jaehoon Chung <[email protected]>
> ---
> drivers/mmc/host/dw_mmc.c | 27 +++++++++++++++++++++------
> drivers/mmc/host/dw_mmc.h | 1 +
> 2 files changed, 22 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 36f98c0..e30d3ed 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -623,6 +623,24 @@ static void mci_send_cmd(struct dw_mci_slot *slot, u32
> cmd, u32 arg)
> cmd, arg, cmd_status);
> }
>
> +static void dw_mci_inform_ciu(struct dw_mci_slot *slot)
> +{
> + struct dw_mci *host = slot->host;
> + unsigned long timeout = jiffies + msecs_to_jiffies(10);
10ms is from test?
> + u32 ctrl, status;
> +
> + do {
> + status = mci_readl(host, STATUS);
> + if (!(status & SDMMC_DATA_BUSY))
> + break;
> + ctrl = mci_readl(host, CTRL);
> + ctrl |= SDMMC_CTRL_RESET;
> + mci_writel(host, CTRL, ctrl);
> + } while (time_before(jiffies, timeout));
> +
> + mci_send_cmd(slot, SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
> +}
> +
> static void dw_mci_setup_bus(struct dw_mci_slot *slot)
> {
> struct dw_mci *host = slot->host;
> @@ -650,15 +668,13 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot)
According to your quotation of manual("Before disabling clock, ...),
Place of dw_mci_inform_ciu is proper here?
dw_mci_inform_ciu(slot);
/* disable clock */
mci_writel(host, CLKENA, 0);
mci_writel(host, CLKSRC, 0);
> mci_writel(host, CLKSRC, 0);
>
> /* inform CIU */
> - mci_send_cmd(slot,
> - SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
> + dw_mci_inform_ciu(slot);
>
> /* set clock to desired speed */
> mci_writel(host, CLKDIV, div);
>
> /* inform CIU */
> - mci_send_cmd(slot,
> - SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
> + dw_mci_inform_ciu(slot);
And then, since start to change clock sequence, there is no need to check
busy-status.
Just need to update clock with origin code.
>
> /* enable clock; only low power if no SDIO */
> clk_en_a = SDMMC_CLKEN_ENABLE << slot->id;
> @@ -667,8 +683,7 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot)
> mci_writel(host, CLKENA, clk_en_a);
>
> /* inform CIU */
> - mci_send_cmd(slot,
> - SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
> + dw_mci_inform_ciu(slot);
Same here.
Thanks,
Seungwon Jeon
>
> host->current_speed = slot->clock;
> }
> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
> index 15c27e1..b6a1a78 100644
> --- a/drivers/mmc/host/dw_mmc.h
> +++ b/drivers/mmc/host/dw_mmc.h
> @@ -127,6 +127,7 @@
> #define SDMMC_CMD_INDX(n) ((n) & 0x1F)
> /* Status register defines */
> #define SDMMC_GET_FCNT(x) (((x)>>17) & 0x1FFF)
> +#define SDMMC_DATA_BUSY BIT(9)
> /* Internal DMAC interrupt defines */
> #define SDMMC_IDMAC_INT_AI BIT(9)
> #define SDMMC_IDMAC_INT_NI BIT(8)
> --
> 1.7.4.1
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