Revert "mmc: core: Remove MMC_CLKGATE"

This reverts commit 9eadcc0581a8ccaf4c2378aa1c193fb164304f1d.

Clock gating is needed for Qualcomm Platforms hence reverting this
upstream patch.

Change-Id: I96ac0c1c7627e8e5c2d18782e2fc08608f0a7f91
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>

10 files changed, 426 insertions, 19 deletions

diff --git a/drivers/mmc/core/Kconfig b/drivers/mmc/core/Kconfig
index 87cc07dedd9f..57cc6b29b2d0 100644
--- a/drivers/mmc/core/Kconfig
+++ b/drivers/mmc/core/Kconfig
@@ -16,3 +16,13 @@ config MMC_PARANOID_SD_INIT
 	  about re-trying SD init requests. This can be a useful
 	  work-around for buggy controllers and hardware. Enable
 	  if you are experiencing issues with SD detection.
+
+config MMC_CLKGATE
+	bool "MMC host clock gating"
+	help
+	  This will attempt to aggressively gate the clock to the MMC card.
+	  This is done to save power due to gating off the logic and bus
+	  noise when the MMC card is not in use. Your host driver has to
+	  support handling this in order for it to be of any use.
+
+	  If unsure, say N.
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 3e54185bc985..55a0e84d004c 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -190,6 +190,8 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
 
 		if (mrq->done)
 			mrq->done(mrq);
+
+		mmc_host_clk_release(host);
 	}
 }
 
@@ -293,6 +295,7 @@ static int mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
 			mrq->stop->mrq = mrq;
 		}
 	}
+	mmc_host_clk_hold(host);
 	led_trigger_event(host->led, LED_FULL);
 	__mmc_start_request(host, mrq);
 
@@ -542,8 +545,11 @@ static void mmc_wait_for_req_done(struct mmc_host *host,
 static void mmc_pre_req(struct mmc_host *host, struct mmc_request *mrq,
 		 bool is_first_req)
 {
-	if (host->ops->pre_req)
+	if (host->ops->pre_req) {
+		mmc_host_clk_hold(host);
 		host->ops->pre_req(host, mrq, is_first_req);
+		mmc_host_clk_release(host);
+	}
 }
 
 /**
@@ -558,8 +564,11 @@ static void mmc_pre_req(struct mmc_host *host, struct mmc_request *mrq,
 static void mmc_post_req(struct mmc_host *host, struct mmc_request *mrq,
 			 int err)
 {
-	if (host->ops->post_req)
+	if (host->ops->post_req) {
+		mmc_host_clk_hold(host);
 		host->ops->post_req(host, mrq, err);
+		mmc_host_clk_release(host);
+	}
 }
 
 /**
@@ -848,9 +857,9 @@ void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card)
 		unsigned int timeout_us, limit_us;
 
 		timeout_us = data->timeout_ns / 1000;
-		if (card->host->ios.clock)
+		if (mmc_host_clk_rate(card->host))
 			timeout_us += data->timeout_clks * 1000 /
-				(card->host->ios.clock / 1000);
+				(mmc_host_clk_rate(card->host) / 1000);
 
 		if (data->flags & MMC_DATA_WRITE)
 			/*
@@ -1048,6 +1057,8 @@ static inline void mmc_set_ios(struct mmc_host *host)
 		 ios->power_mode, ios->chip_select, ios->vdd,
 		 ios->bus_width, ios->timing);
 
+	if (ios->clock > 0)
+		mmc_set_ungated(host);
 	host->ops->set_ios(host, ios);
 }
 
@@ -1056,15 +1067,17 @@ static inline void mmc_set_ios(struct mmc_host *host)
  */
 void mmc_set_chip_select(struct mmc_host *host, int mode)
 {
+	mmc_host_clk_hold(host);
 	host->ios.chip_select = mode;
 	mmc_set_ios(host);
+	mmc_host_clk_release(host);
 }
 
 /*
  * Sets the host clock to the highest possible frequency that
  * is below "hz".
  */
-void mmc_set_clock(struct mmc_host *host, unsigned int hz)
+static void __mmc_set_clock(struct mmc_host *host, unsigned int hz)
 {
 	WARN_ON(hz && hz < host->f_min);
 
@@ -1075,6 +1088,68 @@ void mmc_set_clock(struct mmc_host *host, unsigned int hz)
 	mmc_set_ios(host);
 }
 
+void mmc_set_clock(struct mmc_host *host, unsigned int hz)
+{
+	mmc_host_clk_hold(host);
+	__mmc_set_clock(host, hz);
+	mmc_host_clk_release(host);
+}
+
+#ifdef CONFIG_MMC_CLKGATE
+/*
+ * This gates the clock by setting it to 0 Hz.
+ */
+void mmc_gate_clock(struct mmc_host *host)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&host->clk_lock, flags);
+	host->clk_old = host->ios.clock;
+	host->ios.clock = 0;
+	host->clk_gated = true;
+	spin_unlock_irqrestore(&host->clk_lock, flags);
+	mmc_set_ios(host);
+}
+
+/*
+ * This restores the clock from gating by using the cached
+ * clock value.
+ */
+void mmc_ungate_clock(struct mmc_host *host)
+{
+	/*
+	 * We should previously have gated the clock, so the clock shall
+	 * be 0 here! The clock may however be 0 during initialization,
+	 * when some request operations are performed before setting
+	 * the frequency. When ungate is requested in that situation
+	 * we just ignore the call.
+	 */
+	if (host->clk_old) {
+		BUG_ON(host->ios.clock);
+		/* This call will also set host->clk_gated to false */
+		__mmc_set_clock(host, host->clk_old);
+	}
+}
+
+void mmc_set_ungated(struct mmc_host *host)
+{
+	unsigned long flags;
+
+	/*
+	 * We've been given a new frequency while the clock is gated,
+	 * so make sure we regard this as ungating it.
+	 */
+	spin_lock_irqsave(&host->clk_lock, flags);
+	host->clk_gated = false;
+	spin_unlock_irqrestore(&host->clk_lock, flags);
+}
+
+#else
+void mmc_set_ungated(struct mmc_host *host)
+{
+}
+#endif
+
 int mmc_execute_tuning(struct mmc_card *card)
 {
 	struct mmc_host *host = card->host;
@@ -1089,7 +1164,9 @@ int mmc_execute_tuning(struct mmc_card *card)
 	else
 		opcode = MMC_SEND_TUNING_BLOCK;
 
+	mmc_host_clk_hold(host);
 	err = host->ops->execute_tuning(host, opcode);
+	mmc_host_clk_release(host);
 
 	if (err)
 		pr_err("%s: tuning execution failed\n", mmc_hostname(host));
@@ -1104,8 +1181,10 @@ int mmc_execute_tuning(struct mmc_card *card)
  */
 void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode)
 {
+	mmc_host_clk_hold(host);
 	host->ios.bus_mode = mode;
 	mmc_set_ios(host);
+	mmc_host_clk_release(host);
 }
 
 /*
@@ -1113,8 +1192,10 @@ void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode)
  */
 void mmc_set_bus_width(struct mmc_host *host, unsigned int width)
 {
+	mmc_host_clk_hold(host);
 	host->ios.bus_width = width;
 	mmc_set_ios(host);
+	mmc_host_clk_release(host);
 }
 
 /*
@@ -1555,8 +1636,11 @@ int __mmc_set_signal_voltage(struct mmc_host *host, int signal_voltage)
 	int old_signal_voltage = host->ios.signal_voltage;
 
 	host->ios.signal_voltage = signal_voltage;
-	if (host->ops->start_signal_voltage_switch)
+	if (host->ops->start_signal_voltage_switch) {
+		mmc_host_clk_hold(host);
 		err = host->ops->start_signal_voltage_switch(host, &host->ios);
+		mmc_host_clk_release(host);
+	}
 
 	if (err)
 		host->ios.signal_voltage = old_signal_voltage;
@@ -1590,17 +1674,20 @@ int mmc_set_signal_voltage(struct mmc_host *host, int signal_voltage, u32 ocr)
 		pr_warn("%s: cannot verify signal voltage switch\n",
 			mmc_hostname(host));
 
+	mmc_host_clk_hold(host);
+
 	cmd.opcode = SD_SWITCH_VOLTAGE;
 	cmd.arg = 0;
 	cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
 
 	err = mmc_wait_for_cmd(host, &cmd, 0);
 	if (err)
-		return err;
-
-	if (!mmc_host_is_spi(host) && (cmd.resp[0] & R1_ERROR))
-		return -EIO;
+		goto err_command;
 
+	if (!mmc_host_is_spi(host) && (cmd.resp[0] & R1_ERROR)) {
+		err = -EIO;
+		goto err_command;
+	}
 	/*
 	 * The card should drive cmd and dat[0:3] low immediately
 	 * after the response of cmd11, but wait 1 ms to be sure
@@ -1649,6 +1736,9 @@ power_cycle:
 		mmc_power_cycle(host, ocr);
 	}
 
+err_command:
+	mmc_host_clk_release(host);
+
 	return err;
 }
 
@@ -1657,8 +1747,10 @@ power_cycle:
  */
 void mmc_set_timing(struct mmc_host *host, unsigned int timing)
 {
+	mmc_host_clk_hold(host);
 	host->ios.timing = timing;
 	mmc_set_ios(host);
+	mmc_host_clk_release(host);
 }
 
 /*
@@ -1666,8 +1758,10 @@ void mmc_set_timing(struct mmc_host *host, unsigned int timing)
  */
 void mmc_set_driver_type(struct mmc_host *host, unsigned int drv_type)
 {
+	mmc_host_clk_hold(host);
 	host->ios.drv_type = drv_type;
 	mmc_set_ios(host);
+	mmc_host_clk_release(host);
 }
 
 int mmc_select_drive_strength(struct mmc_card *card, unsigned int max_dtr,
@@ -1675,6 +1769,7 @@ int mmc_select_drive_strength(struct mmc_card *card, unsigned int max_dtr,
 {
 	struct mmc_host *host = card->host;
 	int host_drv_type = SD_DRIVER_TYPE_B;
+	int drive_strength;
 
 	*drv_type = 0;
 
@@ -1697,10 +1792,14 @@ int mmc_select_drive_strength(struct mmc_card *card, unsigned int max_dtr,
 	 * information and let the hardware specific code
 	 * return what is possible given the options
 	 */
-	return host->ops->select_drive_strength(card, max_dtr,
-						host_drv_type,
-						card_drv_type,
-						drv_type);
+	mmc_host_clk_hold(host);
+	drive_strength = host->ops->select_drive_strength(card, max_dtr,
+							  host_drv_type,
+							  card_drv_type,
+							  drv_type);
+	mmc_host_clk_release(host);
+
+	return drive_strength;
 }
 
 /*
@@ -1719,6 +1818,8 @@ void mmc_power_up(struct mmc_host *host, u32 ocr)
 	if (host->ios.power_mode == MMC_POWER_ON)
 		return;
 
+	mmc_host_clk_hold(host);
+
 	mmc_pwrseq_pre_power_on(host);
 
 	host->ios.vdd = fls(ocr) - 1;
@@ -1752,6 +1853,8 @@ void mmc_power_up(struct mmc_host *host, u32 ocr)
 	 * time required to reach a stable voltage.
 	 */
 	mmc_delay(10);
+
+	mmc_host_clk_release(host);
 }
 
 void mmc_power_off(struct mmc_host *host)
@@ -1759,6 +1862,8 @@ void mmc_power_off(struct mmc_host *host)
 	if (host->ios.power_mode == MMC_POWER_OFF)
 		return;
 
+	mmc_host_clk_hold(host);
+
 	mmc_pwrseq_power_off(host);
 
 	host->ios.clock = 0;
@@ -1774,6 +1879,8 @@ void mmc_power_off(struct mmc_host *host)
 	 * can be successfully turned on again.
 	 */
 	mmc_delay(1);
+
+	mmc_host_clk_release(host);
 }
 
 void mmc_power_cycle(struct mmc_host *host, u32 ocr)
@@ -1989,7 +2096,7 @@ static unsigned int mmc_mmc_erase_timeout(struct mmc_card *card,
 		 */
 		timeout_clks <<= 1;
 		timeout_us += (timeout_clks * 1000) /
-			      (card->host->ios.clock / 1000);
+			      (mmc_host_clk_rate(card->host) / 1000);
 
 		erase_timeout = timeout_us / 1000;
 
@@ -2443,7 +2550,9 @@ static void mmc_hw_reset_for_init(struct mmc_host *host)
 {
 	if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
 		return;
+	mmc_host_clk_hold(host);
 	host->ops->hw_reset(host);
+	mmc_host_clk_release(host);
 }
 
 int mmc_hw_reset(struct mmc_host *host)
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 09241e56d628..1a22a82209b2 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -40,6 +40,9 @@ void mmc_init_erase(struct mmc_card *card);
 
 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);
+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);
 u32 mmc_select_voltage(struct mmc_host *host, u32 ocr);
diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index 154aced0b91b..f4db93e03e88 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -255,6 +255,11 @@ void mmc_add_host_debugfs(struct mmc_host *host)
 			&mmc_clock_fops))
 		goto err_node;
 
+#ifdef CONFIG_MMC_CLKGATE
+	if (!debugfs_create_u32("clk_delay", (S_IRUSR | S_IWUSR),
+				root, &host->clk_delay))
+		goto err_node;
+#endif
 #ifdef CONFIG_FAIL_MMC_REQUEST
 	if (fail_request)
 		setup_fault_attr(&fail_default_attr, fail_request);
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index fcf7829c759e..649b8ab923ce 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -61,6 +61,246 @@ void mmc_unregister_host_class(void)
 	class_unregister(&mmc_host_class);
 }
 
+#ifdef CONFIG_MMC_CLKGATE
+static ssize_t clkgate_delay_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct mmc_host *host = cls_dev_to_mmc_host(dev);
+	return snprintf(buf, PAGE_SIZE, "%lu\n", host->clkgate_delay);
+}
+
+static ssize_t clkgate_delay_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct mmc_host *host = cls_dev_to_mmc_host(dev);
+	unsigned long flags, value;
+
+	if (kstrtoul(buf, 0, &value))
+		return -EINVAL;
+
+	spin_lock_irqsave(&host->clk_lock, flags);
+	host->clkgate_delay = value;
+	spin_unlock_irqrestore(&host->clk_lock, flags);
+	return count;
+}
+
+/*
+ * Enabling clock gating will make the core call out to the host
+ * once up and once down when it performs a request or card operation
+ * intermingled in any fashion. The driver will see this through
+ * set_ios() operations with ios.clock field set to 0 to gate (disable)
+ * the block clock, and to the old frequency to enable it again.
+ */
+static void mmc_host_clk_gate_delayed(struct mmc_host *host)
+{
+	unsigned long tick_ns;
+	unsigned long freq = host->ios.clock;
+	unsigned long flags;
+
+	if (!freq) {
+		pr_debug("%s: frequency set to 0 in disable function, "
+			 "this means the clock is already disabled.\n",
+			 mmc_hostname(host));
+		return;
+	}
+	/*
+	 * New requests may have appeared while we were scheduling,
+	 * then there is no reason to delay the check before
+	 * clk_disable().
+	 */
+	spin_lock_irqsave(&host->clk_lock, flags);
+
+	/*
+	 * Delay n bus cycles (at least 8 from MMC spec) before attempting
+	 * to disable the MCI block clock. The reference count may have
+	 * gone up again after this delay due to rescheduling!
+	 */
+	if (!host->clk_requests) {
+		spin_unlock_irqrestore(&host->clk_lock, flags);
+		tick_ns = DIV_ROUND_UP(1000000000, freq);
+		ndelay(host->clk_delay * tick_ns);
+	} else {
+		/* New users appeared while waiting for this work */
+		spin_unlock_irqrestore(&host->clk_lock, flags);
+		return;
+	}
+	mutex_lock(&host->clk_gate_mutex);
+	spin_lock_irqsave(&host->clk_lock, flags);
+	if (!host->clk_requests) {
+		spin_unlock_irqrestore(&host->clk_lock, flags);
+		/* This will set host->ios.clock to 0 */
+		mmc_gate_clock(host);
+		spin_lock_irqsave(&host->clk_lock, flags);
+		pr_debug("%s: gated MCI clock\n", mmc_hostname(host));
+	}
+	spin_unlock_irqrestore(&host->clk_lock, flags);
+	mutex_unlock(&host->clk_gate_mutex);
+}
+
+/*
+ * Internal work. Work to disable the clock at some later point.
+ */
+static void mmc_host_clk_gate_work(struct work_struct *work)
+{
+	struct mmc_host *host = container_of(work, struct mmc_host,
+					      clk_gate_work.work);
+
+	mmc_host_clk_gate_delayed(host);
+}
+
+/**
+ *	mmc_host_clk_hold - ungate hardware MCI clocks
+ *	@host: host to ungate.
+ *
+ *	Makes sure the host ios.clock is restored to a non-zero value
+ *	past this call.	Increase clock reference count and ungate clock
+ *	if we're the first user.
+ */
+void mmc_host_clk_hold(struct mmc_host *host)
+{
+	unsigned long flags;
+
+	/* cancel any clock gating work scheduled by mmc_host_clk_release() */
+	cancel_delayed_work_sync(&host->clk_gate_work);
+	mutex_lock(&host->clk_gate_mutex);
+	spin_lock_irqsave(&host->clk_lock, flags);
+	if (host->clk_gated) {
+		spin_unlock_irqrestore(&host->clk_lock, flags);
+		mmc_ungate_clock(host);
+		spin_lock_irqsave(&host->clk_lock, flags);
+		pr_debug("%s: ungated MCI clock\n", mmc_hostname(host));
+	}
+	host->clk_requests++;
+	spin_unlock_irqrestore(&host->clk_lock, flags);
+	mutex_unlock(&host->clk_gate_mutex);
+}
+
+/**
+ *	mmc_host_may_gate_card - check if this card may be gated
+ *	@card: card to check.
+ */
+static bool mmc_host_may_gate_card(struct mmc_card *card)
+{
+	/* If there is no card we may gate it */
+	if (!card)
+		return true;
+	/*
+	 * Don't gate SDIO cards! These need to be clocked at all times
+	 * since they may be independent systems generating interrupts
+	 * and other events. The clock requests counter from the core will
+	 * go down to zero since the core does not need it, but we will not
+	 * gate the clock, because there is somebody out there that may still
+	 * be using it.
+	 */
+	return !(card->quirks & MMC_QUIRK_BROKEN_CLK_GATING);
+}
+
+/**
+ *	mmc_host_clk_release - gate off hardware MCI clocks
+ *	@host: host to gate.
+ *
+ *	Calls the host driver with ios.clock set to zero as often as possible
+ *	in order to gate off hardware MCI clocks. Decrease clock reference
+ *	count and schedule disabling of clock.
+ */
+void mmc_host_clk_release(struct mmc_host *host)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&host->clk_lock, flags);
+	host->clk_requests--;
+	if (mmc_host_may_gate_card(host->card) &&
+	    !host->clk_requests)
+		schedule_delayed_work(&host->clk_gate_work,
+				      msecs_to_jiffies(host->clkgate_delay));
+	spin_unlock_irqrestore(&host->clk_lock, flags);
+}
+
+/**
+ *	mmc_host_clk_rate - get current clock frequency setting
+ *	@host: host to get the clock frequency for.
+ *
+ *	Returns current clock frequency regardless of gating.
+ */
+unsigned int mmc_host_clk_rate(struct mmc_host *host)
+{
+	unsigned long freq;
+	unsigned long flags;
+
+	spin_lock_irqsave(&host->clk_lock, flags);
+	if (host->clk_gated)
+		freq = host->clk_old;
+	else
+		freq = host->ios.clock;
+	spin_unlock_irqrestore(&host->clk_lock, flags);
+	return freq;
+}
+
+/**
+ *	mmc_host_clk_init - set up clock gating code
+ *	@host: host with potential clock to control
+ */
+static inline void mmc_host_clk_init(struct mmc_host *host)
+{
+	host->clk_requests = 0;
+	/* Hold MCI clock for 8 cycles by default */
+	host->clk_delay = 8;
+	/*
+	 * Default clock gating delay is 0ms to avoid wasting power.
+	 * This value can be tuned by writing into sysfs entry.
+	 */
+	host->clkgate_delay = 0;
+	host->clk_gated = false;
+	INIT_DELAYED_WORK(&host->clk_gate_work, mmc_host_clk_gate_work);
+	spin_lock_init(&host->clk_lock);
+	mutex_init(&host->clk_gate_mutex);
+}
+
+/**
+ *	mmc_host_clk_exit - shut down clock gating code
+ *	@host: host with potential clock to control
+ */
+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 (cancel_delayed_work_sync(&host->clk_gate_work))
+		mmc_host_clk_gate_delayed(host);
+	if (host->clk_gated)
+		mmc_host_clk_hold(host);
+	/* There should be only one user now */
+	WARN_ON(host->clk_requests > 1);
+}
+
+static inline void mmc_host_clk_sysfs_init(struct mmc_host *host)
+{
+	host->clkgate_delay_attr.show = clkgate_delay_show;
+	host->clkgate_delay_attr.store = clkgate_delay_store;
+	sysfs_attr_init(&host->clkgate_delay_attr.attr);
+	host->clkgate_delay_attr.attr.name = "clkgate_delay";
+	host->clkgate_delay_attr.attr.mode = S_IRUGO | S_IWUSR;
+	if (device_create_file(&host->class_dev, &host->clkgate_delay_attr))
+		pr_err("%s: Failed to create clkgate_delay sysfs entry\n",
+				mmc_hostname(host));
+}
+#else
+
+static inline void mmc_host_clk_init(struct mmc_host *host)
+{
+}
+
+static inline void mmc_host_clk_exit(struct mmc_host *host)
+{
+}
+
+static inline void mmc_host_clk_sysfs_init(struct mmc_host *host)
+{
+}
+
+#endif
+
 void mmc_retune_enable(struct mmc_host *host)
 {
 	host->can_retune = 1;
@@ -345,6 +585,8 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 		return NULL;
 	}
 
+	mmc_host_clk_init(host);
+
 	spin_lock_init(&host->lock);
 	init_waitqueue_head(&host->wq);
 	INIT_DELAYED_WORK(&host->detect, mmc_rescan);
@@ -393,6 +635,7 @@ int mmc_add_host(struct mmc_host *host)
 #ifdef CONFIG_DEBUG_FS
 	mmc_add_host_debugfs(host);
 #endif
+	mmc_host_clk_sysfs_init(host);
 
 	mmc_start_host(host);
 	if (!(host->pm_flags & MMC_PM_IGNORE_PM_NOTIFY))
@@ -425,6 +668,8 @@ void mmc_remove_host(struct mmc_host *host)
 	device_del(&host->class_dev);
 
 	led_trigger_unregister_simple(host->led);
+
+	mmc_host_clk_exit(host);
 }
 
 EXPORT_SYMBOL(mmc_remove_host);
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 3a9a79ec4343..dc70b2d7a895 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1976,12 +1976,14 @@ static int mmc_reset(struct mmc_host *host)
 	if (!mmc_can_reset(card))
 		return -EOPNOTSUPP;
 
+	mmc_host_clk_hold(host);
 	mmc_set_clock(host, host->f_init);
 
 	host->ops->hw_reset(host);
 
 	/* Set initial state and call mmc_set_ios */
 	mmc_set_initial_state(host);
+	mmc_host_clk_release(host);
 
 	return mmc_init_card(host, card->ocr, card);
 }
diff --git a/drivers/mmc/core/quirks.c b/drivers/mmc/core/quirks.c
index fad660b95809..dd1d1e0fe322 100644
--- a/drivers/mmc/core/quirks.c
+++ b/drivers/mmc/core/quirks.c
@@ -35,7 +35,25 @@
 #define SDIO_DEVICE_ID_MARVELL_8797_F0	0x9128
 #endif
 
+/*
+ * This hook just adds a quirk for all sdio devices
+ */
+static void add_quirk_for_sdio_devices(struct mmc_card *card, int data)
+{
+	if (mmc_card_sdio(card))
+		card->quirks |= data;
+}
+
 static const struct mmc_fixup mmc_fixup_methods[] = {
+	/* by default sdio devices are considered CLK_GATING broken */
+	/* good cards will be whitelisted as they are tested */
+	SDIO_FIXUP(SDIO_ANY_ID, SDIO_ANY_ID,
+		   add_quirk_for_sdio_devices,
+		   MMC_QUIRK_BROKEN_CLK_GATING),
+
+	SDIO_FIXUP(SDIO_VENDOR_ID_TI, SDIO_DEVICE_ID_TI_WL1271,
+		   remove_quirk, MMC_QUIRK_BROKEN_CLK_GATING),
+
 	SDIO_FIXUP(SDIO_VENDOR_ID_TI, SDIO_DEVICE_ID_TI_WL1271,
 		   add_quirk, MMC_QUIRK_NONSTD_FUNC_IF),
 
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 4ac721fea4ef..5aa0daf621d3 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -800,7 +800,9 @@ static int mmc_sd_get_ro(struct mmc_host *host)
 	if (!host->ops->get_ro)
 		return -1;
 
+	mmc_host_clk_hold(host);
 	ro = host->ops->get_ro(host);
+	mmc_host_clk_release(host);
 
 	return ro;
 }
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index cc93152f82c6..61bb6c739b45 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -977,10 +977,13 @@ static int mmc_sdio_resume(struct mmc_host *host)
 	}
 
 	if (!err && host->sdio_irqs) {
-		if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD))
+		if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
 			wake_up_process(host->sdio_irq_thread);
-		else if (host->caps & MMC_CAP_SDIO_IRQ)
+		} else if (host->caps & MMC_CAP_SDIO_IRQ) {
+			mmc_host_clk_hold(host);
 			host->ops->enable_sdio_irq(host, 1);
+			mmc_host_clk_release(host);
+		}
 	}
 
 	mmc_release_host(host);
diff --git a/drivers/mmc/core/sdio_irq.c b/drivers/mmc/core/sdio_irq.c
index 91bbbfb29f3f..09cc67d028f0 100644
--- a/drivers/mmc/core/sdio_irq.c
+++ b/drivers/mmc/core/sdio_irq.c
@@ -168,15 +168,21 @@ static int sdio_irq_thread(void *_host)
 		}
 
 		set_current_state(TASK_INTERRUPTIBLE);
-		if (host->caps & MMC_CAP_SDIO_IRQ)
+		if (host->caps & MMC_CAP_SDIO_IRQ) {
+			mmc_host_clk_hold(host);
 			host->ops->enable_sdio_irq(host, 1);
+			mmc_host_clk_release(host);
+		}
 		if (!kthread_should_stop())
 			schedule_timeout(period);
 		set_current_state(TASK_RUNNING);
 	} while (!kthread_should_stop());
 
-	if (host->caps & MMC_CAP_SDIO_IRQ)
+	if (host->caps & MMC_CAP_SDIO_IRQ) {
+		mmc_host_clk_hold(host);
 		host->ops->enable_sdio_irq(host, 0);
+		mmc_host_clk_release(host);
+	}
 
 	pr_debug("%s: IRQ thread exiting with code %d\n",
 		 mmc_hostname(host), ret);
@@ -202,7 +208,9 @@ static int sdio_card_irq_get(struct mmc_card *card)
 				return err;
 			}
 		} else if (host->caps & MMC_CAP_SDIO_IRQ) {
+			mmc_host_clk_hold(host);
 			host->ops->enable_sdio_irq(host, 1);
+			mmc_host_clk_release(host);
 		}
 	}
 
@@ -221,7 +229,9 @@ static int sdio_card_irq_put(struct mmc_card *card)
 			atomic_set(&host->sdio_irq_thread_abort, 1);
 			kthread_stop(host->sdio_irq_thread);
 		} else if (host->caps & MMC_CAP_SDIO_IRQ) {
+			mmc_host_clk_hold(host);
 			host->ops->enable_sdio_irq(host, 0);
+			mmc_host_clk_release(host);
 		}
 	}