Hi,
On Thu, Apr 21, 2011 at 3:51 AM, Barry Song <21cnbao@xxxxxxxxx> wrote:
> From: Bin Shi <bin.shi@xxxxxxx>
>
> some controllers share data bus or other pins between
> multi-controllers and need to switch the functions of shared pins
> runtime
> this patch requested those shared pins before actual hardware access
> and release them after access
>
> Signed-off-by: Bin Shi <bin.shi@xxxxxxx>
> Cc: Binghua Duan <binghua.duan@xxxxxxx>
> Signed-off-by: Barry Song <21cnbao@xxxxxxxxx>
> ---
> drivers/mmc/host/sdhci.c | 13 +++++++++++++
> drivers/mmc/host/sdhci.h | 2 ++
> include/linux/mmc/sdhci.h | 2 ++
> 3 files changed, 17 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index f31077d..7b07152 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1379,6 +1379,13 @@ static void sdhci_tasklet_finish(unsigned long param)
> sdhci_reset(host, SDHCI_RESET_DATA);
> }
>
> + /*
> + * some controllers share data bus or other pins between multi-controller
> + * and need to switch the function of pins runtime
> + */
> + if (host->quirks & SDHCI_QUIRK_SHARED_PINS)
> + host->ops->get_shared_pins(host);
> +
Why in tasklet_finish? Why not in sdhci_request?
No need to waste a quirk flag. Just invoke if method is not NULL.
Also, I would assume host->ops->get_shared_pins would need to
synchronize with other SDHCI instances
it shares the pins with. Since you do it after the host->lock (as you
should), what happens if get_shared_pins needs to wait?
Can you show the rest (sdhci driver implementing these hooks)?
> host->mrq = NULL;
> host->cmd = NULL;
> host->data = NULL;
> @@ -1391,6 +1398,12 @@ static void sdhci_tasklet_finish(unsigned long param)
> spin_unlock_irqrestore(&host->lock, flags);
>
> mmc_request_done(host->mmc, mrq);
> +
> + /*
> + * release shared pins so that other controllers can use them
> + */
> + if (host->quirks & SDHCI_QUIRK_SHARED_PINS)
> + host->ops->get_shared_pins(host);
> }
>
> static void sdhci_timeout_timer(unsigned long data)
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 85750a9..9d918a5 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -229,6 +229,8 @@ struct sdhci_ops {
> void (*platform_send_init_74_clocks)(struct sdhci_host *host,
> u8 power_mode);
> unsigned int (*get_ro)(struct sdhci_host *host);
> + unsigned int (*get_shared_pins)(struct sdhci_host *host);
> + unsigned int (*put_shared_pins)(struct sdhci_host *host);
> };
>
> #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS
> diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
> index 83bd9f7..32ab422 100644
> --- a/include/linux/mmc/sdhci.h
> +++ b/include/linux/mmc/sdhci.h
> @@ -85,6 +85,8 @@ struct sdhci_host {
> #define SDHCI_QUIRK_NO_HISPD_BIT (1<<29)
> /* Controller treats ADMA descriptors with length 0000h incorrectly */
> #define SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC (1<<30)
> +/* Controller shared data bus or other pins with other controllers */
> +#define SDHCI_QUIRK_SHARED_PINS (1<<31)
>
> int irq; /* Device IRQ */
> void __iomem *ioaddr; /* Mapped address */
> --
> 1.7.1
> --
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