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

From: smohideen
Date: Tue Dec 02 2008 - 11:47:29 EST


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@xxxxxxxxx>
>
> 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.


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