On Mon, Jun 20, 2011 at 3:06 PM, Simon Horman <horms@xxxxxxxxxxxx> wrote:
> Some controllers require waiting for the bus to become idle
> before writing to some registers. I have implemented this
> by adding a hook to sd_ctrl_write16() and implementing
> a hook for SDHI which waits for the bus to become idle.
>
> Cc: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> Cc: Magnus Damm <magnus.damm@xxxxxxxxx>
> Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>
>
> ---
Hi Simon,
Thanks for your work on this!
> --- a/drivers/mmc/host/sh_mobile_sdhi.c
> +++ b/drivers/mmc/host/sh_mobile_sdhi.c
> @@ -55,6 +57,37 @@ static int sh_mobile_sdhi_get_cd(struct platform_device *pdev)
> return -ENOSYS;
> }
>
> +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;
and
> @@ -86,6 +119,7 @@ static int __devinit sh_mobile_sdhi_probe(struct platform_device *pdev)
> mmc_data->hclk = clk_get_rate(priv->clk);
> mmc_data->set_pwr = sh_mobile_sdhi_set_pwr;
> mmc_data->get_cd = sh_mobile_sdhi_get_cd;
> + mmc_data->write16_hook = sh_mobile_sdhi_write16_hook;
> mmc_data->capabilities = MMC_CAP_MMC_HIGHSPEED;
> if (p) {
> mmc_data->flags = p->tmio_flags;
Doesn't it make more sense to do:
if (!(host->pdata->flags & TMIO_MMC_HAS_IDLE_WAIT))
mmc_data->write16_hook = sh_mobile_sdhi_write16_hook;
and skip the check inside the sh_mobile_sdhi_write16_hook() function?
No need to do that check on every register access unless really needed.
Thanks,
/ magnus
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