On Mon, 28 Jun 2010 03:20:41 +0200
Lars-Peter Clausen <lars@xxxxxxxxxx> wrote:
> This patch adds support for the mmc controller on JZ4740 SoCs.
>
> Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxx>
> Cc: linux-mmc@xxxxxxxxxxxxxxx
>
> ...
>
> +#define JZ4740_MMC_MAX_TIMEOUT 10000000
That was a really big timeout. How long do 1e7 readw's take? Oh well.
>
> ...
>
> +static void jz4740_mmc_clock_disable(struct jz4740_mmc_host *host)
> +{
> + uint32_t status;
> +
> + writew(JZ_MMC_STRPCL_CLOCK_STOP, host->base + JZ_REG_MMC_STRPCL);
> + do {
> + status = readl(host->base + JZ_REG_MMC_STATUS);
> + } while (status & JZ_MMC_STATUS_CLK_EN);
> +}
> +
> +static void jz4740_mmc_reset(struct jz4740_mmc_host *host)
> +{
> + uint32_t status;
> +
> + writew(JZ_MMC_STRPCL_RESET, host->base + JZ_REG_MMC_STRPCL);
> + udelay(10);
> + do {
> + status = readl(host->base + JZ_REG_MMC_STATUS);
> + } while (status & JZ_MMC_STATUS_IS_RESETTING);
> +}
Maybe these should have a timeout too?
>
> ...
>
> +static inline unsigned int jz4740_mmc_wait_irq(struct jz4740_mmc_host *host,
> + unsigned int irq)
> +{
> + unsigned int timeout = JZ4740_MMC_MAX_TIMEOUT;
> + uint16_t status;
> +
> + do {
> + status = readw(host->base + JZ_REG_MMC_IREG);
> + } while (!(status & irq) && --timeout);
> +
> + return timeout;
> +}
This guy's too big to inline. Recent gcc's know that and they tend to
uninline such things behind your back anwyay.
>
> ...
>
> +struct jz4740_mmc_platform_data {
> + int gpio_power;
> + int gpio_card_detect;
> + int gpio_read_only;
> + unsigned card_detect_active_low:1;
> + unsigned read_only_active_low:1;
> + unsigned power_active_low:1;
> +
> + unsigned data_1bit:1;
> +};
The bitfields will all share the same word, so modification of one
field can race against modification of another field. Hence some form
of locking which covers *all* the bitfields is needed.
Is that a problem in this driver?
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