libata: add deadline support to prereset and reset methods

Add @deadline to prereset and reset methods and make them honor it.
ata_wait_ready() which directly takes @deadline is implemented to be
used as the wait function.  This patch is in preparation for EH timing
improvements.

* ata_wait_ready() never does busy sleep.  It's only used from EH and
  no wait in EH is that urgent.  This function also prints 'be
  patient' message automatically after 5 secs of waiting if more than
  3 secs is remaining till deadline.

* ata_bus_post_reset() now fails with error code if any of its wait
  fails.  This is important because earlier reset tries will have
  shorter timeout than the spec requires.  If a device fails to
  respond before the short timeout, reset should be retried with
  longer timeout rather than silently ignoring the device.

  There are three behavior differences.

  1. Timeout is applied to both devices at once, not separately.  This
     is more consistent with what the spec says.

  2. When a device passes devchk but fails to become ready before
     deadline.  Previouly, post_reset would just succeed and let
     device classification remove the device.  New code fails the
     reset thus causing reset retry.  After a few times, EH will give
     up disabling the port.

  3. When slave device passes devchk but fails to become accessible
     (TF-wise) after reset.  Original code disables dev1 after 30s
     timeout and continues as if the device doesn't exist, while the
     patched code fails reset.  When this happens, new code fails
     reset on whole port rather than proceeding with only the primary
     device.

  If the failing device is suffering transient problems, new code
  retries reset which is a better behavior.  If the failing device is
  actually broken, the net effect is identical to it, but not to the
  other device sharing the channel.  In the previous code, reset would
  have succeeded after 30s thus detecting the working one.  In the new
  code, reset fails and whole port gets disabled.  IMO, it's a
  pathological case anyway (broken device sharing bus with working
  one) and doesn't really matter.

* ata_bus_softreset() is changed to return error code from
  ata_bus_post_reset().  It used to return 0 unconditionally.

* Spin up waiting is to be removed and not converted to honor
  deadline.

* To be on the safe side, deadline is set to 40s for the time being.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 113 insertions, 48 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index ca67484..84e9448 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2979,23 +2979,68 @@ int ata_busy_sleep(struct ata_port *ap,
 	return 0;
 }
 
-static void ata_bus_post_reset(struct ata_port *ap, unsigned int devmask)
+/**
+ *	ata_wait_ready - sleep until BSY clears, or timeout
+ *	@ap: port containing status register to be polled
+ *	@deadline: deadline jiffies for the operation
+ *
+ *	Sleep until ATA Status register bit BSY clears, or timeout
+ *	occurs.
+ *
+ *	LOCKING:
+ *	Kernel thread context (may sleep).
+ *
+ *	RETURNS:
+ *	0 on success, -errno otherwise.
+ */
+int ata_wait_ready(struct ata_port *ap, unsigned long deadline)
+{
+	unsigned long start = jiffies;
+	int warned = 0;
+
+	while (1) {
+		u8 status = ata_chk_status(ap);
+		unsigned long now = jiffies;
+
+		if (!(status & ATA_BUSY))
+			return 0;
+		if (status == 0xff)
+			return -ENODEV;
+		if (time_after(now, deadline))
+			return -EBUSY;
+
+		if (!warned && time_after(now, start + 5 * HZ) &&
+		    (deadline - now > 3 * HZ)) {
+			ata_port_printk(ap, KERN_WARNING,
+				"port is slow to respond, please be patient "
+				"(Status 0x%x)\n", status);
+			warned = 1;
+		}
+
+		msleep(50);
+	}
+}
+
+static int ata_bus_post_reset(struct ata_port *ap, unsigned int devmask,
+			      unsigned long deadline)
 {
 	struct ata_ioports *ioaddr = &ap->ioaddr;
 	unsigned int dev0 = devmask & (1 << 0);
 	unsigned int dev1 = devmask & (1 << 1);
-	unsigned long timeout;
+	int rc;
 
 	/* if device 0 was found in ata_devchk, wait for its
 	 * BSY bit to clear
 	 */
-	if (dev0)
-		ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT);
+	if (dev0) {
+		rc = ata_wait_ready(ap, deadline);
+		if (rc && rc != -ENODEV)
+			return rc;
+	}
 
 	/* if device 1 was found in ata_devchk, wait for
 	 * register access, then wait for BSY to clear
 	 */
-	timeout = jiffies + ATA_TMOUT_BOOT;
 	while (dev1) {
 		u8 nsect, lbal;
 
@@ -3004,14 +3049,15 @@ static void ata_bus_post_reset(struct ata_port *ap, unsigned int devmask)
 		lbal = ioread8(ioaddr->lbal_addr);
 		if ((nsect == 1) && (lbal == 1))
 			break;
-		if (time_after(jiffies, timeout)) {
-			dev1 = 0;
-			break;
-		}
+		if (time_after(jiffies, deadline))
+			return -EBUSY;
 		msleep(50);	/* give drive a breather */
 	}
-	if (dev1)
-		ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT);
+	if (dev1) {
+		rc = ata_wait_ready(ap, deadline);
+		if (rc && rc != -ENODEV)
+			return rc;
+	}
 
 	/* is all this really necessary? */
 	ap->ops->dev_select(ap, 0);
@@ -3019,10 +3065,12 @@ static void ata_bus_post_reset(struct ata_port *ap, unsigned int devmask)
 		ap->ops->dev_select(ap, 1);
 	if (dev0)
 		ap->ops->dev_select(ap, 0);
+
+	return 0;
 }
 
-static unsigned int ata_bus_softreset(struct ata_port *ap,
-				      unsigned int devmask)
+static int ata_bus_softreset(struct ata_port *ap, unsigned int devmask,
+			     unsigned long deadline)
 {
 	struct ata_ioports *ioaddr = &ap->ioaddr;
 
@@ -3054,9 +3102,7 @@ static unsigned int ata_bus_softreset(struct ata_port *ap,
 	if (ata_check_status(ap) == 0xFF)
 		return 0;
 
-	ata_bus_post_reset(ap, devmask);
-
-	return 0;
+	return ata_bus_post_reset(ap, devmask, deadline);
 }
 
 /**
@@ -3107,7 +3153,7 @@ void ata_bus_reset(struct ata_port *ap)
 
 	/* issue bus reset */
 	if (ap->flags & ATA_FLAG_SRST)
-		if (ata_bus_softreset(ap, devmask))
+		if (ata_bus_softreset(ap, devmask, jiffies + 40 * HZ))
 			goto err_out;
 
 	/*
@@ -3150,29 +3196,37 @@ err_out:
  *	sata_phy_debounce - debounce SATA phy status
  *	@ap: ATA port to debounce SATA phy status for
  *	@params: timing parameters { interval, duratinon, timeout } in msec
+ *	@deadline: deadline jiffies for the operation
  *
  *	Make sure SStatus of @ap reaches stable state, determined by
  *	holding the same value where DET is not 1 for @duration polled
  *	every @interval, before @timeout.  Timeout constraints the
- *	beginning of the stable state.  Because, after hot unplugging,
- *	DET gets stuck at 1 on some controllers, this functions waits
+ *	beginning of the stable state.  Because DET gets stuck at 1 on
+ *	some controllers after hot unplugging, this functions waits
  *	until timeout then returns 0 if DET is stable at 1.
  *
+ *	@timeout is further limited by @deadline.  The sooner of the
+ *	two is used.
+ *
  *	LOCKING:
  *	Kernel thread context (may sleep)
  *
  *	RETURNS:
  *	0 on success, -errno on failure.
  */
-int sata_phy_debounce(struct ata_port *ap, const unsigned long *params)
+int sata_phy_debounce(struct ata_port *ap, const unsigned long *params,
+		      unsigned long deadline)
 {
 	unsigned long interval_msec = params[0];
-	unsigned long duration = params[1] * HZ / 1000;
-	unsigned long timeout = jiffies + params[2] * HZ / 1000;
-	unsigned long last_jiffies;
+	unsigned long duration = msecs_to_jiffies(params[1]);
+	unsigned long last_jiffies, t;
 	u32 last, cur;
 	int rc;
 
+	t = jiffies + msecs_to_jiffies(params[2]);
+	if (time_before(t, deadline))
+		deadline = t;
+
 	if ((rc = sata_scr_read(ap, SCR_STATUS, &cur)))
 		return rc;
 	cur &= 0xf;
@@ -3188,7 +3242,7 @@ int sata_phy_debounce(struct ata_port *ap, const unsigned long *params)
 
 		/* DET stable? */
 		if (cur == last) {
-			if (cur == 1 && time_before(jiffies, timeout))
+			if (cur == 1 && time_before(jiffies, deadline))
 				continue;
 			if (time_after(jiffies, last_jiffies + duration))
 				return 0;
@@ -3199,8 +3253,8 @@ int sata_phy_debounce(struct ata_port *ap, const unsigned long *params)
 		last = cur;
 		last_jiffies = jiffies;
 
-		/* check timeout */
-		if (time_after(jiffies, timeout))
+		/* check deadline */
+		if (time_after(jiffies, deadline))
 			return -EBUSY;
 	}
 }
@@ -3209,6 +3263,7 @@ int sata_phy_debounce(struct ata_port *ap, const unsigned long *params)
  *	sata_phy_resume - resume SATA phy
  *	@ap: ATA port to resume SATA phy for
  *	@params: timing parameters { interval, duratinon, timeout } in msec
+ *	@deadline: deadline jiffies for the operation
  *
  *	Resume SATA phy of @ap and debounce it.
  *
@@ -3218,7 +3273,8 @@ int sata_phy_debounce(struct ata_port *ap, const unsigned long *params)
  *	RETURNS:
  *	0 on success, -errno on failure.
  */
-int sata_phy_resume(struct ata_port *ap, const unsigned long *params)
+int sata_phy_resume(struct ata_port *ap, const unsigned long *params,
+		    unsigned long deadline)
 {
 	u32 scontrol;
 	int rc;
@@ -3236,10 +3292,10 @@ int sata_phy_resume(struct ata_port *ap, const unsigned long *params)
 	 */
 	msleep(200);
 
-	return sata_phy_debounce(ap, params);
+	return sata_phy_debounce(ap, params, deadline);
 }
 
-static void ata_wait_spinup(struct ata_port *ap)
+static void ata_wait_spinup(struct ata_port *ap, unsigned long deadline)
 {
 	struct ata_eh_context *ehc = &ap->eh_context;
 	unsigned long end, secs;
@@ -3247,7 +3303,7 @@ static void ata_wait_spinup(struct ata_port *ap)
 
 	/* first, debounce phy if SATA */
 	if (ap->cbl == ATA_CBL_SATA) {
-		rc = sata_phy_debounce(ap, sata_deb_timing_hotplug);
+		rc = sata_phy_debounce(ap, sata_deb_timing_hotplug, deadline);
 
 		/* if debounced successfully and offline, no need to wait */
 		if ((rc == 0 || rc == -EOPNOTSUPP) && ata_port_offline(ap))
@@ -3271,6 +3327,7 @@ static void ata_wait_spinup(struct ata_port *ap)
 /**
  *	ata_std_prereset - prepare for reset
  *	@ap: ATA port to be reset
+ *	@deadline: deadline jiffies for the operation
  *
  *	@ap is about to be reset.  Initialize it.
  *
@@ -3280,7 +3337,7 @@ static void ata_wait_spinup(struct ata_port *ap)
  *	RETURNS:
  *	0 on success, -errno otherwise.
  */
-int ata_std_prereset(struct ata_port *ap)
+int ata_std_prereset(struct ata_port *ap, unsigned long deadline)
 {
 	struct ata_eh_context *ehc = &ap->eh_context;
 	const unsigned long *timing = sata_ehc_deb_timing(ehc);
@@ -3293,7 +3350,7 @@ int ata_std_prereset(struct ata_port *ap)
 
 	if ((ehc->i.flags & ATA_EHI_HOTPLUGGED) &&
 	    (ap->flags & ATA_FLAG_SKIP_D2H_BSY))
-		ata_wait_spinup(ap);
+		ata_wait_spinup(ap, deadline);
 
 	/* if we're about to do hardreset, nothing more to do */
 	if (ehc->i.action & ATA_EH_HARDRESET)
@@ -3301,7 +3358,7 @@ int ata_std_prereset(struct ata_port *ap)
 
 	/* if SATA, resume phy */
 	if (ap->cbl == ATA_CBL_SATA) {
-		rc = sata_phy_resume(ap, timing);
+		rc = sata_phy_resume(ap, timing, deadline);
 		if (rc && rc != -EOPNOTSUPP) {
 			/* phy resume failed */
 			ata_port_printk(ap, KERN_WARNING, "failed to resume "
@@ -3314,7 +3371,7 @@ int ata_std_prereset(struct ata_port *ap)
 	 * Reg FIS and we don't know that no device is attached.
 	 */
 	if (!(ap->flags & ATA_FLAG_SKIP_D2H_BSY) && !ata_port_offline(ap))
-		ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT);
+		ata_wait_ready(ap, deadline);
 
 	return 0;
 }
@@ -3323,6 +3380,7 @@ int ata_std_prereset(struct ata_port *ap)
  *	ata_std_softreset - reset host port via ATA SRST
  *	@ap: port to reset
  *	@classes: resulting classes of attached devices
+ *	@deadline: deadline jiffies for the operation
  *
  *	Reset host port using ATA SRST.
  *
@@ -3332,10 +3390,12 @@ int ata_std_prereset(struct ata_port *ap)
  *	RETURNS:
  *	0 on success, -errno otherwise.
  */
-int ata_std_softreset(struct ata_port *ap, unsigned int *classes)
+int ata_std_softreset(struct ata_port *ap, unsigned int *classes,
+		      unsigned long deadline)
 {
 	unsigned int slave_possible = ap->flags & ATA_FLAG_SLAVE_POSS;
-	unsigned int devmask = 0, err_mask;
+	unsigned int devmask = 0;
+	int rc;
 	u8 err;
 
 	DPRINTK("ENTER\n");
@@ -3356,11 +3416,10 @@ int ata_std_softreset(struct ata_port *ap, unsigned int *classes)
 
 	/* issue bus reset */
 	DPRINTK("about to softreset, devmask=%x\n", devmask);
-	err_mask = ata_bus_softreset(ap, devmask);
-	if (err_mask) {
-		ata_port_printk(ap, KERN_ERR, "SRST failed (err_mask=0x%x)\n",
-				err_mask);
-		return -EIO;
+	rc = ata_bus_softreset(ap, devmask, deadline);
+	if (rc) {
+		ata_port_printk(ap, KERN_ERR, "SRST failed (errno=%d)\n", rc);
+		return rc;
 	}
 
 	/* determine by signature whether we have ATA or ATAPI devices */
@@ -3377,6 +3436,7 @@ int ata_std_softreset(struct ata_port *ap, unsigned int *classes)
  *	sata_port_hardreset - reset port via SATA phy reset
  *	@ap: port to reset
  *	@timing: timing parameters { interval, duratinon, timeout } in msec
+ *	@deadline: deadline jiffies for the operation
  *
  *	SATA phy-reset host port using DET bits of SControl register.
  *
@@ -3386,7 +3446,8 @@ int ata_std_softreset(struct ata_port *ap, unsigned int *classes)
  *	RETURNS:
  *	0 on success, -errno otherwise.
  */
-int sata_port_hardreset(struct ata_port *ap, const unsigned long *timing)
+int sata_port_hardreset(struct ata_port *ap, const unsigned long *timing,
+			unsigned long deadline)
 {
 	u32 scontrol;
 	int rc;
@@ -3425,7 +3486,7 @@ int sata_port_hardreset(struct ata_port *ap, const unsigned long *timing)
 	msleep(1);
 
 	/* bring phy back */
-	rc = sata_phy_resume(ap, timing);
+	rc = sata_phy_resume(ap, timing, deadline);
  out:
 	DPRINTK("EXIT, rc=%d\n", rc);
 	return rc;
@@ -3435,6 +3496,7 @@ int sata_port_hardreset(struct ata_port *ap, const unsigned long *timing)
  *	sata_std_hardreset - reset host port via SATA phy reset
  *	@ap: port to reset
  *	@class: resulting class of attached device
+ *	@deadline: deadline jiffies for the operation
  *
  *	SATA phy-reset host port using DET bits of SControl register,
  *	wait for !BSY and classify the attached device.
@@ -3445,7 +3507,8 @@ int sata_port_hardreset(struct ata_port *ap, const unsigned long *timing)
  *	RETURNS:
  *	0 on success, -errno otherwise.
  */
-int sata_std_hardreset(struct ata_port *ap, unsigned int *class)
+int sata_std_hardreset(struct ata_port *ap, unsigned int *class,
+		       unsigned long deadline)
 {
 	const unsigned long *timing = sata_ehc_deb_timing(&ap->eh_context);
 	int rc;
@@ -3453,7 +3516,7 @@ int sata_std_hardreset(struct ata_port *ap, unsigned int *class)
 	DPRINTK("ENTER\n");
 
 	/* do hardreset */
-	rc = sata_port_hardreset(ap, timing);
+	rc = sata_port_hardreset(ap, timing, deadline);
 	if (rc) {
 		ata_port_printk(ap, KERN_ERR,
 				"COMRESET failed (errno=%d)\n", rc);
@@ -3470,10 +3533,11 @@ int sata_std_hardreset(struct ata_port *ap, unsigned int *class)
 	/* wait a while before checking status, see SRST for more info */
 	msleep(150);
 
-	if (ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT)) {
+	rc = ata_wait_ready(ap, deadline);
+	if (rc && rc != -ENODEV) {
 		ata_port_printk(ap, KERN_ERR,
-				"COMRESET failed (device not ready)\n");
-		return -EIO;
+				"COMRESET failed (errno=%d)\n", rc);
+		return rc;
 	}
 
 	ap->ops->dev_select(ap, 0);	/* probably unnecessary */
@@ -6793,6 +6857,7 @@ EXPORT_SYMBOL_GPL(ata_port_disable);
 EXPORT_SYMBOL_GPL(ata_ratelimit);
 EXPORT_SYMBOL_GPL(ata_wait_register);
 EXPORT_SYMBOL_GPL(ata_busy_sleep);
+EXPORT_SYMBOL_GPL(ata_wait_ready);
 EXPORT_SYMBOL_GPL(ata_port_queue_task);
 EXPORT_SYMBOL_GPL(ata_scsi_ioctl);
 EXPORT_SYMBOL_GPL(ata_scsi_queuecmd);