Re: [patch 1/8] SDHCI: Add timeout hooks

[smohideen@mx2.labs.rootshell.ws]

On Tue, Dec 02, 2008 at 03:40:19PM +0000, Ben Dooks wrote:
> Some controllers do not provide clock information in their
> capabilities (in the Samsung case, it is because there are
> multiple clock sources available to the controller). Add hooks
> to allow the system to supply clock information.
> 
> Signed-off-by: Ben Dooks <ben-linux@fluff.org>
> 
> Index: linux.git/drivers/mmc/host/sdhci.c
> ===================================================================
> --- linux.git.orig/drivers/mmc/host/sdhci.c	2008-12-01 19:11:54.000000000 +0000
> +++ linux.git/drivers/mmc/host/sdhci.c	2008-12-01 19:24:14.000000000 +0000
> @@ -1606,18 +1606,26 @@ int sdhci_add_host(struct sdhci_host *ho
>  
>  	host->max_clk =
>  		(caps & SDHCI_CLOCK_BASE_MASK) >> SDHCI_CLOCK_BASE_SHIFT;
> +	host->max_clk *= 1000000;
>  	if (host->max_clk == 0) {
> -		printk(KERN_ERR "%s: Hardware doesn't specify base clock "
> -			"frequency.\n", mmc_hostname(mmc));
> +		if (host->ops->get_max_clock)
> +			host->max_clk = host->ops->get_max_clock(host);
> +		else
> +			printk(KERN_ERR
> +			       "%s: Hardware doesn't specify base clock "
> +			       "frequency.\n", mmc_hostname(mmc));
>  		return -ENODEV;
>  	}
> -	host->max_clk *= 1000000;
>  
>  	host->timeout_clk =
>  		(caps & SDHCI_TIMEOUT_CLK_MASK) >> SDHCI_TIMEOUT_CLK_SHIFT;
>  	if (host->timeout_clk == 0) {
> -		printk(KERN_ERR "%s: Hardware doesn't specify timeout clock "
> -			"frequency.\n", mmc_hostname(mmc));
> +		if (host->ops->get_timeout_clock)
> +			host->timeout_clk = host->ops->get_timeout_clock(host);
> +		else
> +			printk(KERN_ERR
> +			       "%s: Hardware doesn't specify timeout clock "
> +			       "frequency.\n", mmc_hostname(mmc));
>  		return -ENODEV;
>  	}
>  	if (caps & SDHCI_TIMEOUT_CLK_UNIT)
> Index: linux.git/drivers/mmc/host/sdhci.h
> ===================================================================
> --- linux.git.orig/drivers/mmc/host/sdhci.h	2008-12-01 19:11:54.000000000 +0000
> +++ linux.git/drivers/mmc/host/sdhci.h	2008-12-01 19:17:55.000000000 +0000
> @@ -267,6 +267,8 @@ struct sdhci_host {
>  
>  struct sdhci_ops {
>  	int		(*enable_dma)(struct sdhci_host *host);
> +	unsigned int	(*get_max_clock)(struct sdhci_host *host);
> +	unsigned int	(*get_timeout_clock)(struct sdhci_host *host);
>  };
>  

	Can we cache the multiple dereferences. Here host->ops can be
	saved to a local, instead of multiple dereference several time.