[1/3] mmc: add support for h/w clock gating of sd controller

Commit Message

Philip Rakity Dec. 3, 2010, 7:26 p.m. UTC

None

Patch

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 6286898..c8bba7d 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -131,7 +131,10 @@  void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
 		if (mrq->done)
 			mrq->done(mrq);
 
-		mmc_host_clk_gate(host);
+#ifdef CONFIG_MMC_CLKGATE
+		if ((host->caps & MMC_CAP_CLOCK_GATING_HW) == 0)
+			mmc_host_clk_gate(host);
+#endif
 	}
 }
 
@@ -192,7 +195,10 @@  mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
 			mrq->stop->mrq = mrq;
 		}
 	}
-	mmc_host_clk_ungate(host);
+#ifdef CONFIG_MMC_CLKGATE
+	if ((host->caps & MMC_CAP_CLOCK_GATING_HW) == 0)
+		mmc_host_clk_ungate(host);
+#endif
 	host->ops->request(host, mrq);
 }
 
@@ -1547,8 +1553,14 @@  void mmc_rescan(struct work_struct *work)
 		pr_info("%s: %s: trying to init card at %u Hz\n",
 			mmc_hostname(host), __func__, host->f_init);
 #endif
-		mmc_power_up(host);
+
+#ifdef CONFIG_MMC_CLKGATE
+		if (host->caps & MMC_CAP_CLOCK_GATING_HW)
+			mmc_hwungate_clock(host);
+#endif
 		sdio_reset(host);
+		mmc_power_up(host);
+
 		mmc_go_idle(host);
 
 		mmc_send_if_cond(host, host->ocr_avail);
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 026c975..184d56b 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -35,6 +35,25 @@  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
+/*
+ * This gates the clock by enabling driver h/w gating
+ */
+static inline void mmc_hwgate_clock(struct mmc_host *host)
+{
+	host->clk_gated = true;
+}
+
+/*
+ * This ungates the clock by turning off h/w gating
+ */
+static inline void mmc_hwungate_clock(struct mmc_host *host)
+{
+	host->clk_gated = false;
+}
+#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..ace748e 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -282,7 +282,10 @@  struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 	host->class_dev.class = &mmc_host_class;
 	device_initialize(&host->class_dev);
 
-	mmc_host_clk_init(host);
+#ifdef CONFIG_MMC_CLKGATE
+	if ((host->caps & MMC_CAP_CLOCK_GATING_HW) == 0)
+		mmc_host_clk_init(host);
+#endif
 
 	spin_lock_init(&host->lock);
 	init_waitqueue_head(&host->wq);
@@ -366,7 +369,10 @@  void mmc_remove_host(struct mmc_host *host)
 
 	led_trigger_unregister_simple(host->led);
 
-	mmc_host_clk_exit(host);
+#ifdef CONFIG_MMC_CLKGATE
+	if ((host->caps & MMC_CAP_CLOCK_GATING_HW) == 0)
+		mmc_host_clk_exit(host);
+#endif
 }
 
 EXPORT_SYMBOL(mmc_remove_host);
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 0eccd96..195e557 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -517,6 +517,11 @@  static int mmc_init_card(struct mmc_host *host, u32 ocr,
 
 	mmc_set_clock(host, max_dtr);
 
+#ifdef CONFIG_MMC_CLKGATE
+	if (host->caps & MMC_CAP_CLOCK_GATING_HW)
+		mmc_hwgate_clock(host);
+#endif
+
 	/*
 	 * Indicate DDR mode (if supported).
 	 */
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 49da4df..04e0d6f 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -618,6 +618,10 @@  static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
 	else if (err)
 		goto free_card;
 
+#ifdef CONFIG_MMC_CLKGATE
+	if (host->caps & MMC_CAP_CLOCK_GATING_HW)
+		mmc_hwgate_clock(host);
+#endif
 	/*
 	 * Set bus speed.
 	 */
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index efef5f9..52fbbb7 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -488,6 +488,11 @@  static int mmc_sdio_init_card(struct mmc_host *host, u32 ocr,
 	else if (err)
 		goto remove;
 
+#ifdef CONFIG_MMC_CLKGATE
+	if (host->caps & MMC_CAP_CLOCK_GATING_HW)
+		mmc_hwungate_clock(host);
+#endif
+
 	/*
 	 * Change to the card's maximum speed.
 	 */
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 078cff7..30ce755 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_CLOCK_GATING_HW	(1 << 15)	/* h/w supports clock gating */
 	mmc_pm_flag_t		pm_caps;	/* supported pm features */
 
 #ifdef CONFIG_MMC_CLKGATE