2011/4/25 Barry Song <21cn...@gmail.com>: > 2011/4/21 Andrei Warkentin <andr...@motorola.com>: >> Hi, >> >> On Thu, Apr 21, 2011 at 3:51 AM, Barry Song <21cn...@gmail.com> wrote: >>> From: Bin Shi <bin....@csr.com> >>> >>> 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....@csr.com> >>> Cc: Binghua Duan <binghua.d...@csr.com> >>> Signed-off-by: Barry Song <21cn...@gmail.com> >>> --- >>> 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? > > that is ok in sdhci_request > >> No need to waste a quirk flag. Just invoke if method is not NULL. > > i think most hardwares have no shared pins issue, it should be a quirk > but not a generic option for all devices. > >> >> 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? > > sorry, just due to my cross-eye while porting the patch from old > kernel to linux-mmc tree. In fact i mean: > > /* > * 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); > > > 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); >
In fact we request shared pins in sdhci_request() and release them in tasklet_finish. Then i'll send patch v2. >> Can you show the rest (sdhci driver implementing these hooks)? > > Yes. sdhci driver implement these hooks, special behavior of getting > shared pins depends on special hardware, for us, we just request data > bus mutex and set related hardware registers to switch the role of > shared pins. > >> >>> 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 >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in >>> the body of a message to majord...@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html