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Commit 3f46540e authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'mmc-v4.14-rc4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc 

Pull MMC fixes from Ulf Hansson:
 "Fix dw_mmc request timeout issues"

* tag 'mmc-v4.14-rc4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc:
  mmc: dw_mmc: Fix the DTO timeout calculation
  mmc: dw_mmc: Add locking to the CTO timer
  mmc: dw_mmc: Fix the CTO timeout calculation
  mmc: dw_mmc: cancel the CTO timer after a voltage switch
parents e65a139d 9d9491a7

drivers/mmc/host/dw_mmc.c

+94 −13
Original line number Diff line number Diff line
@@ -401,16 +401,37 @@ static u32 dw_mci_prep_stop_abort(struct dw_mci *host, struct mmc_command *cmd) 
static inline void dw_mci_set_cto(struct dw_mci *host)

{

	unsigned int cto_clks;

	unsigned int cto_div;

	unsigned int cto_ms;

	unsigned long irqflags;



	cto_clks = mci_readl(host, TMOUT) & 0xff;

	cto_ms = DIV_ROUND_UP(cto_clks, host->bus_hz / 1000);

	cto_div = (mci_readl(host, CLKDIV) & 0xff) * 2;

	if (cto_div == 0)

		cto_div = 1;

	cto_ms = DIV_ROUND_UP(MSEC_PER_SEC * cto_clks * cto_div, host->bus_hz);



	/* add a bit spare time */

	cto_ms += 10;



	/*

	 * The durations we're working with are fairly short so we have to be

	 * extra careful about synchronization here.  Specifically in hardware a

	 * command timeout is _at most_ 5.1 ms, so that means we expect an

	 * interrupt (either command done or timeout) to come rather quickly

	 * after the mci_writel.  ...but just in case we have a long interrupt

	 * latency let's add a bit of paranoia.

	 *

	 * In general we'll assume that at least an interrupt will be asserted

	 * in hardware by the time the cto_timer runs.  ...and if it hasn't

	 * been asserted in hardware by that time then we'll assume it'll never

	 * come.

	 */

	spin_lock_irqsave(&host->irq_lock, irqflags);

	if (!test_bit(EVENT_CMD_COMPLETE, &host->pending_events))

		mod_timer(&host->cto_timer,

			jiffies + msecs_to_jiffies(cto_ms) + 1);

	spin_unlock_irqrestore(&host->irq_lock, irqflags);

}



static void dw_mci_start_command(struct dw_mci *host,
@@ -425,11 +446,11 @@ static void dw_mci_start_command(struct dw_mci *host, 
	wmb(); /* drain writebuffer */

	dw_mci_wait_while_busy(host, cmd_flags);



	mci_writel(host, CMD, cmd_flags | SDMMC_CMD_START);



	/* response expected command only */

	if (cmd_flags & SDMMC_CMD_RESP_EXP)

		dw_mci_set_cto(host);



	mci_writel(host, CMD, cmd_flags | SDMMC_CMD_START);

}



static inline void send_stop_abort(struct dw_mci *host, struct mmc_data *data)
@@ -1915,10 +1936,15 @@ static int dw_mci_data_complete(struct dw_mci *host, struct mmc_data *data) 
static void dw_mci_set_drto(struct dw_mci *host)

{

	unsigned int drto_clks;

	unsigned int drto_div;

	unsigned int drto_ms;



	drto_clks = mci_readl(host, TMOUT) >> 8;

	drto_ms = DIV_ROUND_UP(drto_clks, host->bus_hz / 1000);

	drto_div = (mci_readl(host, CLKDIV) & 0xff) * 2;

	if (drto_div == 0)

		drto_div = 1;

	drto_ms = DIV_ROUND_UP(MSEC_PER_SEC * drto_clks * drto_div,

			       host->bus_hz);



	/* add a bit spare time */

	drto_ms += 10;
@@ -1926,6 +1952,24 @@ static void dw_mci_set_drto(struct dw_mci *host) 
	mod_timer(&host->dto_timer, jiffies + msecs_to_jiffies(drto_ms));

}



static bool dw_mci_clear_pending_cmd_complete(struct dw_mci *host)

{

	if (!test_bit(EVENT_CMD_COMPLETE, &host->pending_events))

		return false;



	/*

	 * Really be certain that the timer has stopped.  This is a bit of

	 * paranoia and could only really happen if we had really bad

	 * interrupt latency and the interrupt routine and timeout were

	 * running concurrently so that the del_timer() in the interrupt

	 * handler couldn't run.

	 */

	WARN_ON(del_timer_sync(&host->cto_timer));

	clear_bit(EVENT_CMD_COMPLETE, &host->pending_events);



	return true;

}



static void dw_mci_tasklet_func(unsigned long priv)

{

	struct dw_mci *host = (struct dw_mci *)priv;
@@ -1952,8 +1996,7 @@ static void dw_mci_tasklet_func(unsigned long priv) 


		case STATE_SENDING_CMD11:

		case STATE_SENDING_CMD:

			if (!test_and_clear_bit(EVENT_CMD_COMPLETE,

						&host->pending_events))

			if (!dw_mci_clear_pending_cmd_complete(host))

				break;



			cmd = host->cmd;
@@ -2122,8 +2165,7 @@ static void dw_mci_tasklet_func(unsigned long priv) 
			/* fall through */



		case STATE_SENDING_STOP:

			if (!test_and_clear_bit(EVENT_CMD_COMPLETE,

						&host->pending_events))

			if (!dw_mci_clear_pending_cmd_complete(host))

				break;



			/* CMD error in data command */
@@ -2570,6 +2612,8 @@ static void dw_mci_write_data_pio(struct dw_mci *host) 


static void dw_mci_cmd_interrupt(struct dw_mci *host, u32 status)

{

	del_timer(&host->cto_timer);



	if (!host->cmd_status)

		host->cmd_status = status;
@@ -2594,6 +2638,7 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id) 
	struct dw_mci *host = dev_id;

	u32 pending;

	struct dw_mci_slot *slot = host->slot;

	unsigned long irqflags;



	pending = mci_readl(host, MINTSTS); /* read-only mask reg */
@@ -2601,8 +2646,6 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id) 
		/* Check volt switch first, since it can look like an error */

		if ((host->state == STATE_SENDING_CMD11) &&

		    (pending & SDMMC_INT_VOLT_SWITCH)) {

			unsigned long irqflags;



			mci_writel(host, RINTSTS, SDMMC_INT_VOLT_SWITCH);

			pending &= ~SDMMC_INT_VOLT_SWITCH;
@@ -2618,11 +2661,15 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id) 
		}



		if (pending & DW_MCI_CMD_ERROR_FLAGS) {

			spin_lock_irqsave(&host->irq_lock, irqflags);



			del_timer(&host->cto_timer);

			mci_writel(host, RINTSTS, DW_MCI_CMD_ERROR_FLAGS);

			host->cmd_status = pending;

			smp_wmb(); /* drain writebuffer */

			set_bit(EVENT_CMD_COMPLETE, &host->pending_events);



			spin_unlock_irqrestore(&host->irq_lock, irqflags);

		}



		if (pending & DW_MCI_DATA_ERROR_FLAGS) {
@@ -2662,9 +2709,12 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id) 
		}



		if (pending & SDMMC_INT_CMD_DONE) {

			del_timer(&host->cto_timer);

			spin_lock_irqsave(&host->irq_lock, irqflags);



			mci_writel(host, RINTSTS, SDMMC_INT_CMD_DONE);

			dw_mci_cmd_interrupt(host, pending);



			spin_unlock_irqrestore(&host->irq_lock, irqflags);

		}



		if (pending & SDMMC_INT_CD) {
@@ -2938,7 +2988,35 @@ static void dw_mci_cmd11_timer(unsigned long arg) 
static void dw_mci_cto_timer(unsigned long arg)

{

	struct dw_mci *host = (struct dw_mci *)arg;

	unsigned long irqflags;

	u32 pending;



	spin_lock_irqsave(&host->irq_lock, irqflags);



	/*

	 * If somehow we have very bad interrupt latency it's remotely possible

	 * that the timer could fire while the interrupt is still pending or

	 * while the interrupt is midway through running.  Let's be paranoid

	 * and detect those two cases.  Note that this is paranoia is somewhat

	 * justified because in this function we don't actually cancel the

	 * pending command in the controller--we just assume it will never come.

	 */

	pending = mci_readl(host, MINTSTS); /* read-only mask reg */

	if (pending & (DW_MCI_CMD_ERROR_FLAGS | SDMMC_INT_CMD_DONE)) {

		/* The interrupt should fire; no need to act but we can warn */

		dev_warn(host->dev, "Unexpected interrupt latency\n");

		goto exit;

	}

	if (test_bit(EVENT_CMD_COMPLETE, &host->pending_events)) {

		/* Presumably interrupt handler couldn't delete the timer */

		dev_warn(host->dev, "CTO timeout when already completed\n");

		goto exit;

	}



	/*

	 * Continued paranoia to make sure we're in the state we expect.

	 * This paranoia isn't really justified but it seems good to be safe.

	 */

	switch (host->state) {

	case STATE_SENDING_CMD11:

	case STATE_SENDING_CMD:
@@ -2957,6 +3035,9 @@ static void dw_mci_cto_timer(unsigned long arg) 
			 host->state);

		break;

	}



exit:

	spin_unlock_irqrestore(&host->irq_lock, irqflags);

}



static void dw_mci_dto_timer(unsigned long arg)