mmc: core: Remove MMC_CLKGATE

MMC_CLKGATE was once invented to save power by gating the bus clock at
request inactivity. At that time it served its purpose. The modern way to
deal with power saving for these scenarios, is by using runtime PM.

Nowadays, several host drivers have deployed runtime PM, but for those
that haven't and which still cares power saving at request inactivity,
it's certainly time to deploy runtime PM as it has been around for several
years now.

To simplify code to mmc core and thus decrease maintenance efforts, this
patch removes all code related to MMC_CLKGATE.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 15 insertions, 124 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 21cda23b247c..1a36b021b44e 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -187,8 +187,6 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
 
 		if (mrq->done)
 			mrq->done(mrq);
-
-		mmc_host_clk_release(host);
 	}
 }
 
@@ -292,7 +290,6 @@ 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);
 
@@ -542,11 +539,8 @@ 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) {
-		mmc_host_clk_hold(host);
+	if (host->ops->pre_req)
 		host->ops->pre_req(host, mrq, is_first_req);
-		mmc_host_clk_release(host);
-	}
 }
 
 /**
@@ -561,11 +555,8 @@ 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) {
-		mmc_host_clk_hold(host);
+	if (host->ops->post_req)
 		host->ops->post_req(host, mrq, err);
-		mmc_host_clk_release(host);
-	}
 }
 
 /**
@@ -850,9 +841,9 @@ 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 (mmc_host_clk_rate(card->host))
+		if (card->host->ios.clock)
 			timeout_us += data->timeout_clks * 1000 /
-				(mmc_host_clk_rate(card->host) / 1000);
+				(card->host->ios.clock / 1000);
 
 		if (data->flags & MMC_DATA_WRITE)
 			/*
@@ -1050,8 +1041,6 @@ 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);
 }
 
@@ -1060,17 +1049,15 @@ 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".
  */
-static void __mmc_set_clock(struct mmc_host *host, unsigned int hz)
+void mmc_set_clock(struct mmc_host *host, unsigned int hz)
 {
 	WARN_ON(hz && hz < host->f_min);
 
@@ -1081,68 +1068,6 @@ static 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;
@@ -1157,9 +1082,7 @@ 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));
@@ -1174,10 +1097,8 @@ 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);
 }
 
 /*
@@ -1185,10 +1106,8 @@ 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);
 }
 
 /*
@@ -1532,11 +1451,8 @@ 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) {
-		mmc_host_clk_hold(host);
+	if (host->ops->start_signal_voltage_switch)
 		err = host->ops->start_signal_voltage_switch(host, &host->ios);
-		mmc_host_clk_release(host);
-	}
 
 	if (err)
 		host->ios.signal_voltage = old_signal_voltage;
@@ -1570,20 +1486,17 @@ 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)
-		goto err_command;
+		return err;
+
+	if (!mmc_host_is_spi(host) && (cmd.resp[0] & R1_ERROR))
+		return -EIO;
 
-	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
@@ -1632,9 +1545,6 @@ power_cycle:
 		mmc_power_cycle(host, ocr);
 	}
 
-err_command:
-	mmc_host_clk_release(host);
-
 	return err;
 }
 
@@ -1643,10 +1553,8 @@ err_command:
  */
 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);
 }
 
 /*
@@ -1654,10 +1562,8 @@ 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,
@@ -1665,7 +1571,6 @@ 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;
 
@@ -1688,14 +1593,10 @@ 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
 	 */
-	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;
+	return host->ops->select_drive_strength(card, max_dtr,
+						host_drv_type,
+						card_drv_type,
+						drv_type);
 }
 
 /*
@@ -1714,8 +1615,6 @@ 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;
@@ -1749,8 +1648,6 @@ 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)
@@ -1758,8 +1655,6 @@ 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;
@@ -1775,8 +1670,6 @@ 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)
@@ -1992,7 +1885,7 @@ static unsigned int mmc_mmc_erase_timeout(struct mmc_card *card,
 		 */
 		timeout_clks <<= 1;
 		timeout_us += (timeout_clks * 1000) /
-			      (mmc_host_clk_rate(card->host) / 1000);
+			      (card->host->ios.clock / 1000);
 
 		erase_timeout = timeout_us / 1000;
 
@@ -2440,9 +2333,7 @@ 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)