[PATCH 1/6] mmc: sdhci: add platfrom get_max_timeout hook

[Shawn Guo]

On Tue, Dec 10, 2013 at 08:56:03PM +0800, Dong Aisheng wrote:
> Currently the max_discard_to is simply got by (1 << 27) / host->timeout_clk
> which is assumed to be the maximum timeout value, however, some platforms
> maximum timeout counter may not be 1 << 27, e.g. i.MX uSDHC is 1 << 28.
> Thus 1 << 27 may not be correct for such platforms.
> 
> It is also possible that other platforms may have different problems.
> To be flexible, we add a get_max_timeout hook to get the correct
> maximum timeout value for these platforms.
> 
> Signed-off-by: Dong Aisheng <b29396 at freescale.com>
> Reported-by: Ed Sutter <ed.sutter at alcatel-lucent.com>
> ---
>  drivers/mmc/host/sdhci.c |    5 ++++-
>  drivers/mmc/host/sdhci.h |    1 +
>  2 files changed, 5 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index bd8a098..464d42c 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2930,7 +2930,10 @@ int sdhci_add_host(struct sdhci_host *host)
>  	if (host->quirks & SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK)
>  		host->timeout_clk = mmc->f_max / 1000;
>  
> -	mmc->max_discard_to = (1 << 27) / host->timeout_clk;
> +	if (host->ops->get_max_timeout)
> +		mmc->max_discard_to = host->ops->get_max_timeout(host);

Does "timeout" conceptually equals to "discard_to"?  If not, we might
want to write it in the either form below to avoid messing these two
concepts.

	mmc->max_discard_to = host->ops->get_max_timeout(host) / host->timeout_clk;

or

	mmc->max_discard_to = host->ops->get_max_discard_to(host);

I guess you may want to go for the second one.

Shawn

> +	else
> +		mmc->max_discard_to = (1 << 27) / host->timeout_clk;
>  
>  	mmc->caps |= MMC_CAP_SDIO_IRQ | MMC_CAP_ERASE | MMC_CAP_CMD23;
>  
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 0a3ed01..1591cbb 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -281,6 +281,7 @@ struct sdhci_ops {
>  	unsigned int	(*get_max_clock)(struct sdhci_host *host);
>  	unsigned int	(*get_min_clock)(struct sdhci_host *host);
>  	unsigned int	(*get_timeout_clock)(struct sdhci_host *host);
> +	unsigned int	(*get_max_timeout)(struct sdhci_host *host);
>  	int		(*platform_bus_width)(struct sdhci_host *host,
>  					       int width);
>  	void (*platform_send_init_74_clocks)(struct sdhci_host *host,
> -- 
> 1.7.2.rc3
> 
>