Re: [PATCH 3/5] mmc: sdhi: Add write16_hook

Paul Mundt
2011-06-20T06:25:22Z

On Mon, Jun 20, 2011 at 03:06:53PM +0900, Simon Horman wrote:
> diff --git a/drivers/mmc/host/sh_mobile_sdhi.c b/drivers/mmc/host/sh_mobile_sdhi.c
> index b365429..6c56453 100644
> --- a/drivers/mmc/host/sh_mobile_sdhi.c
> +++ b/drivers/mmc/host/sh_mobile_sdhi.c
> @@ -27,6 +27,8 @@
> #include <linux/mfd/tmio.h>
> #include <linux/sh_dma.h>
>
> +#include <asm/delay.h>
> +
> #include "tmio_mmc.h"
>
linux/delay.h will suffice.

> +static void sh_mobile_sdhi_wait_idle(struct tmio_mmc_host *host)
> +{
> + int timeout = 1000;
> +
> + while (--timeout && !(sd_ctrl_read16(host, CTL_STATUS2) & (1 << 13)))
> + udelay(1);
> +
> + if (!timeout)
> + dev_warn(host->pdata->dev, "timeout waiting for SD bus idle\n");
> +
> +}
> +
> +static void sh_mobile_sdhi_write16_hook(struct tmio_mmc_host *host, int addr)
> +{
> + if (!(host->pdata->flags & TMIO_MMC_HAS_IDLE_WAIT))
> + return;
> +
> + switch (addr)
> + {
> + case CTL_SD_CMD:
> + case CTL_STOP_INTERNAL_ACTION:
> + case CTL_XFER_BLK_COUNT:
> + case CTL_SD_CARD_CLK_CTL:
> + case CTL_SD_XFER_LEN:
> + case CTL_SD_MEM_CARD_OPT:
> + case CTL_TRANSACTION_CTL:
> + case CTL_DMA_ENABLE:
> + sh_mobile_sdhi_wait_idle(host);
> + }
> +}
> +
The timeout error should really be handed down.

> diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
> index 0c22df0..5912cf3 100644
> --- a/drivers/mmc/host/tmio_mmc.h
> +++ b/drivers/mmc/host/tmio_mmc.h
> @@ -153,6 +153,8 @@ static inline u32 sd_ctrl_read32(struct tmio_mmc_host *host, int addr)
>
> static inline void sd_ctrl_write16(struct tmio_mmc_host *host, int addr, u16 val)
> {
> + if (host->pdata->write16_hook)
> + host->pdata->write16_hook(host, addr);
> writew(val, host->ctl + (addr << host->bus_shift));
> }
>
If it times out you are unlikely to want to proceed with the write. At
best you end up with a lost write cycle, at worst potentially a bus
lockup you can't easily recover from.