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Tue, 7 Dec 2010 09:56:40 -0800 From: Philip Rakity To: "linux-mmc@vger.kernel.org" CC: Nicolas Pitre , Mark Brown , Chris Ball Date: Tue, 7 Dec 2010 09:56:38 -0800 Subject: [PATCH V2 1/3] mmc: add support for H/W clock gating of SD controller Thread-Topic: [PATCH V2 1/3] mmc: add support for H/W clock gating of SD controller Thread-Index: AcuWOBmzK2hUzukqT1u2RMxHLBoSOA== Message-ID: <4DB58728-19A4-4ECC-979B-A3EF1F880382@marvell.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US MIME-Version: 1.0 Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter1.kernel.org [140.211.167.41]); Tue, 07 Dec 2010 18:00:36 +0000 (UTC) diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 6286898..de867d1 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -682,6 +682,28 @@ void mmc_ungate_clock(struct mmc_host *host) } } +/* + * Let hardware automatically gate the clock when the card becomes idle + */ +void mmc_hwgate_clock(struct mmc_host *host) +{ + if (host->caps & MMC_CAP_HW_CLOCK_GATING) { + host->clk_gated = true; + mmc_set_ios(host); + } +} + +/* + * This ungates the clock by turning off h/w gating + */ +void mmc_hwungate_clock(struct mmc_host *host) +{ + if (host->caps & MMC_CAP_HW_CLOCK_GATING) { + host->clk_gated = false; + mmc_set_ios(host); + } +} + void mmc_set_ungated(struct mmc_host *host) { unsigned long flags; @@ -1548,6 +1570,8 @@ void mmc_rescan(struct work_struct *work) mmc_hostname(host), __func__, host->f_init); #endif mmc_power_up(host); + + mmc_hwungate_clock(host); sdio_reset(host); mmc_go_idle(host); @@ -1569,6 +1593,10 @@ void mmc_rescan(struct work_struct *work) if (mmc_attach_sd(host, ocr)) mmc_power_off(host); + + /* hw clock gating is off when we get here */ + /* do not enable clock gating for sdio cards */ + /* sdio cards can miss interrupts */ } goto out; } @@ -1580,6 +1608,8 @@ void mmc_rescan(struct work_struct *work) if (!err) { if (mmc_attach_sd(host, ocr)) mmc_power_off(host); + else + mmc_hwgate_clock(host); goto out; } @@ -1590,6 +1620,8 @@ void mmc_rescan(struct work_struct *work) if (!err) { if (mmc_attach_mmc(host, ocr)) mmc_power_off(host); + else + mmc_hwgate_clock(host); goto out; } diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h index 026c975..3810e28 100644 --- a/drivers/mmc/core/core.h +++ b/drivers/mmc/core/core.h @@ -35,6 +35,19 @@ void mmc_set_chip_select(struct mmc_host *host, int mode); void mmc_set_clock(struct mmc_host *host, unsigned int hz); void mmc_gate_clock(struct mmc_host *host); void mmc_ungate_clock(struct mmc_host *host); + +#ifdef CONFIG_MMC_CLKGATE +void mmc_hwgate_clock(struct mmc_host *host); +void mmc_hwungate_clock(struct mmc_host *host); +#else +static inline void mmc_hwgate_clock(struct mmc_host *host) +{ +} + +static inline void mmc_hwungate_clock(struct mmc_host *host) +{ +} +#endif void mmc_set_ungated(struct mmc_host *host); void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode); void mmc_set_bus_width(struct mmc_host *host, unsigned int width); diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c index 92e3370..afadcf4 100644 --- a/drivers/mmc/core/host.c +++ b/drivers/mmc/core/host.c @@ -130,6 +130,9 @@ void mmc_host_clk_ungate(struct mmc_host *host) { unsigned long flags; + if (host->caps & MMC_CAP_HW_CLOCK_GATING) + return; + mutex_lock(&host->clk_gate_mutex); spin_lock_irqsave(&host->clk_lock, flags); if (host->clk_gated) { @@ -178,10 +181,13 @@ void mmc_host_clk_gate(struct mmc_host *host) { unsigned long flags; + if (host->caps & MMC_CAP_HW_CLOCK_GATING) + return; + spin_lock_irqsave(&host->clk_lock, flags); host->clk_requests--; if (mmc_host_may_gate_card(host->card) && - !host->clk_requests) + !host->clk_requests) schedule_work(&host->clk_gate_work); spin_unlock_irqrestore(&host->clk_lock, flags); } @@ -212,6 +218,9 @@ unsigned int mmc_host_clk_rate(struct mmc_host *host) */ static inline void mmc_host_clk_init(struct mmc_host *host) { + if (host->caps & MMC_CAP_HW_CLOCK_GATING) + return; + host->clk_requests = 0; /* Hold MCI clock for 8 cycles by default */ host->clk_delay = 8; @@ -231,6 +240,9 @@ static inline void mmc_host_clk_exit(struct mmc_host *host) * Wait for any outstanding gate and then make sure we're * ungated before exiting. */ + if (host->caps & MMC_CAP_HW_CLOCK_GATING) + return; + if (cancel_work_sync(&host->clk_gate_work)) mmc_host_clk_gate_delayed(host); if (host->clk_gated) diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 078cff7..243c7ab 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -171,6 +171,7 @@ struct mmc_host { #define MMC_CAP_POWER_OFF_CARD (1 << 13) /* Can power off after boot */ #define MMC_CAP_BUS_WIDTH_TEST (1 << 14) /* CMD14/CMD19 bus width ok */ +#define MMC_CAP_HW_CLOCK_GATING (1 << 15) /* h/w supports clock gating */ mmc_pm_flag_t pm_caps; /* supported pm features */ #ifdef CONFIG_MMC_CLKGATE