libata: use ata_exec_internal() for PMP register access

PMP registers used to be accessed with dedicated accessors ->pmp_read
and ->pmp_write.  During reset, those callbacks are called with the
port frozen so they should be able to run without depending on
interrupt delivery.  To achieve this, they were implemented polling.

However, as resetting the host port makes the PMP to isolate fan-out
ports until SError.X is cleared, resetting fan-out ports while port is
frozen doesn't buy much additional safety.

This patch updates libata PMP support such that PMP registers are
accessed using regular ata_exec_internal() mechanism and kills
->pmp_read/write() callbacks.  The following changes are made.

* PMP access helpers - sata_pmp_read_init_tf(), sata_pmp_read_val(),
  sata_pmp_write_init_tf() are folded into sata_pmp_read/write() which
  are now standalone PMP register access functions.

* sata_pmp_read/write() returns err_mask instead of rc.  This is
  consistent with other functions which issue internal commands and
  allows more detailed error reporting.

* ahci interrupt handler is modified to ignore BAD_PMP and
  spurious/illegal completion IRQs while reset is in progress.  These
  conditions are expected during reset.

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

1 files changed, 92 insertions, 117 deletions

diff --git a/drivers/ata/libata-pmp.c b/drivers/ata/libata-pmp.c
index f6c4b11336e9..c0c4dbcde091 100644
--- a/drivers/ata/libata-pmp.c
+++ b/drivers/ata/libata-pmp.c
@@ -17,27 +17,35 @@
  *	@reg: register to read
  *	@r_val: resulting value
  *
- *	Wrapper around ap->ops->pmp_read to make it easier to call and
- *	nomarlize error return value.
+ *	Read PMP register.
  *
  *	LOCKING:
  *	Kernel thread context (may sleep).
  *
  *	RETURNS:
- *	0 on success, -errno on failure.
+ *	0 on success, AC_ERR_* mask on failure.
  */
-static int sata_pmp_read(struct ata_link *link, int reg, u32 *r_val)
+static unsigned int sata_pmp_read(struct ata_link *link, int reg, u32 *r_val)
 {
 	struct ata_port *ap = link->ap;
 	struct ata_device *pmp_dev = ap->link.device;
-	int rc;
-
-	might_sleep();
-
-	rc = ap->ops->pmp_read(pmp_dev, link->pmp, reg, r_val);
-	if (rc)
-		rc = -EIO;
-	return rc;
+	struct ata_taskfile tf;
+	unsigned int err_mask;
+
+	ata_tf_init(pmp_dev, &tf);
+	tf.command = ATA_CMD_PMP_READ;
+	tf.protocol = ATA_PROT_NODATA;
+	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+	tf.feature = reg;
+	tf.device = link->pmp;
+
+	err_mask = ata_exec_internal(pmp_dev, &tf, NULL, DMA_NONE, NULL, 0,
+				     SATA_PMP_SCR_TIMEOUT);
+	if (err_mask)
+		return err_mask;
+
+	*r_val = tf.nsect | tf.lbal << 8 | tf.lbam << 16 | tf.lbah << 24;
+	return 0;
 }
 
 /**
@@ -46,27 +54,33 @@ static int sata_pmp_read(struct ata_link *link, int reg, u32 *r_val)
  *	@reg: register to write
  *	@r_val: value to write
  *
- *	Wrapper around ap->ops->pmp_write to make it easier to call
- *	and nomarlize error return value.
+ *	Write PMP register.
  *
  *	LOCKING:
  *	Kernel thread context (may sleep).
  *
  *	RETURNS:
- *	0 on success, -errno on failure.
+ *	0 on success, AC_ERR_* mask on failure.
  */
-static int sata_pmp_write(struct ata_link *link, int reg, u32 val)
+static unsigned int sata_pmp_write(struct ata_link *link, int reg, u32 val)
 {
 	struct ata_port *ap = link->ap;
 	struct ata_device *pmp_dev = ap->link.device;
-	int rc;
-
-	might_sleep();
-
-	rc = ap->ops->pmp_write(pmp_dev, link->pmp, reg, val);
-	if (rc)
-		rc = -EIO;
-	return rc;
+	struct ata_taskfile tf;
+
+	ata_tf_init(pmp_dev, &tf);
+	tf.command = ATA_CMD_PMP_WRITE;
+	tf.protocol = ATA_PROT_NODATA;
+	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+	tf.feature = reg;
+	tf.device = link->pmp;
+	tf.nsect = val & 0xff;
+	tf.lbal = (val >> 8) & 0xff;
+	tf.lbam = (val >> 16) & 0xff;
+	tf.lbah = (val >> 24) & 0xff;
+
+	return ata_exec_internal(pmp_dev, &tf, NULL, DMA_NONE, NULL, 0,
+				 SATA_PMP_SCR_TIMEOUT);
 }
 
 /**
@@ -100,71 +114,6 @@ int sata_pmp_qc_defer_cmd_switch(struct ata_queued_cmd *qc)
 }
 
 /**
- *	sata_pmp_read_init_tf - initialize TF for PMP read
- *	@tf: taskfile to initialize
- *	@dev: PMP dev
- *	@pmp: port multiplier port number
- *	@reg: register to read
- *
- *	Initialize @tf for PMP read command.
- *
- *	LOCKING:
- *	None.
- */
-void sata_pmp_read_init_tf(struct ata_taskfile *tf,
-			   struct ata_device *dev, int pmp, int reg)
-{
-	ata_tf_init(dev, tf);
-	tf->command = ATA_CMD_PMP_READ;
-	tf->protocol = ATA_PROT_NODATA;
-	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
-	tf->feature = reg;
-	tf->device = pmp;
-}
-
-/**
- *	sata_pmp_read_val - extract PMP read result from TF
- *	@tf: target TF
- *
- *	Determine PMP read result from @tf.
- *
- *	LOCKING:
- *	None.
- */
-u32 sata_pmp_read_val(const struct ata_taskfile *tf)
-{
-	return tf->nsect | tf->lbal << 8 | tf->lbam << 16 | tf->lbah << 24;
-}
-
-/**
- *	sata_pmp_read_init_tf - initialize TF for PMP write
- *	@tf: taskfile to initialize
- *	@dev: PMP dev
- *	@pmp: port multiplier port number
- *	@reg: register to read
- *	@val: value to write
- *
- *	Initialize @tf for PMP write command.
- *
- *	LOCKING:
- *	None.
- */
-void sata_pmp_write_init_tf(struct ata_taskfile *tf,
-			    struct ata_device *dev, int pmp, int reg, u32 val)
-{
-	ata_tf_init(dev, tf);
-	tf->command = ATA_CMD_PMP_WRITE;
-	tf->protocol = ATA_PROT_NODATA;
-	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
-	tf->feature = reg;
-	tf->device = pmp;
-	tf->nsect = val & 0xff;
-	tf->lbal = (val >> 8) & 0xff;
-	tf->lbam = (val >> 16) & 0xff;
-	tf->lbah = (val >> 24) & 0xff;
-}
-
-/**
  *	sata_pmp_scr_read - read PSCR
  *	@link: ATA link to read PSCR for
  *	@reg: PSCR to read
@@ -181,10 +130,18 @@ void sata_pmp_write_init_tf(struct ata_taskfile *tf,
  */
 int sata_pmp_scr_read(struct ata_link *link, int reg, u32 *r_val)
 {
+	unsigned int err_mask;
+
 	if (reg > SATA_PMP_PSCR_CONTROL)
 		return -EINVAL;
 
-	return sata_pmp_read(link, reg, r_val);
+	err_mask = sata_pmp_read(link, reg, r_val);
+	if (err_mask) {
+		ata_link_printk(link, KERN_WARNING, "failed to read SCR %d "
+				"(Emask=0x%x)\n", reg, err_mask);
+		return -EIO;
+	}
+	return 0;
 }
 
 /**
@@ -204,10 +161,18 @@ int sata_pmp_scr_read(struct ata_link *link, int reg, u32 *r_val)
  */
 int sata_pmp_scr_write(struct ata_link *link, int reg, u32 val)
 {
+	unsigned int err_mask;
+
 	if (reg > SATA_PMP_PSCR_CONTROL)
 		return -EINVAL;
 
-	return sata_pmp_write(link, reg, val);
+	err_mask = sata_pmp_write(link, reg, val);
+	if (err_mask) {
+		ata_link_printk(link, KERN_WARNING, "failed to write SCR %d "
+				"(Emask=0x%x)\n", reg, err_mask);
+		return -EIO;
+	}
+	return 0;
 }
 
 /**
@@ -361,16 +326,17 @@ void sata_pmp_std_postreset(struct ata_link *link, unsigned int *class)
 static int sata_pmp_read_gscr(struct ata_device *dev, u32 *gscr)
 {
 	static const int gscr_to_read[] = { 0, 1, 2, 32, 33, 64, 96 };
-	int i, rc;
+	int i;
 
 	for (i = 0; i < ARRAY_SIZE(gscr_to_read); i++) {
 		int reg = gscr_to_read[i];
+		unsigned int err_mask;
 
-		rc = sata_pmp_read(dev->link, reg, &gscr[reg]);
-		if (rc) {
-			ata_dev_printk(dev, KERN_ERR, "failed to read "
-				       "PMP GSCR[%d] (errno=%d)\n", reg, rc);
-			return rc;
+		err_mask = sata_pmp_read(dev->link, reg, &gscr[reg]);
+		if (err_mask) {
+			ata_dev_printk(dev, KERN_ERR, "failed to read PMP "
+				"GSCR[%d] (Emask=0x%x)\n", reg, err_mask);
+			return -EIO;
 		}
 	}
 
@@ -392,6 +358,7 @@ static int sata_pmp_configure(struct ata_device *dev, int print_info)
 {
 	struct ata_port *ap = dev->link->ap;
 	u32 *gscr = dev->gscr;
+	unsigned int err_mask = 0;
 	const char *reason;
 	int nr_ports, rc;
 
@@ -408,8 +375,10 @@ static int sata_pmp_configure(struct ata_device *dev, int print_info)
 		dev->flags |= ATA_DFLAG_AN;
 
 	/* monitor SERR_PHYRDY_CHG on fan-out ports */
-	rc = sata_pmp_write(dev->link, SATA_PMP_GSCR_ERROR_EN, SERR_PHYRDY_CHG);
-	if (rc) {
+	err_mask = sata_pmp_write(dev->link, SATA_PMP_GSCR_ERROR_EN,
+				  SERR_PHYRDY_CHG);
+	if (err_mask) {
+		rc = -EIO;
 		reason = "failed to write GSCR_ERROR_EN";
 		goto fail;
 	}
@@ -418,9 +387,10 @@ static int sata_pmp_configure(struct ata_device *dev, int print_info)
 	if (gscr[SATA_PMP_GSCR_FEAT_EN] & SATA_PMP_FEAT_NOTIFY) {
 		gscr[SATA_PMP_GSCR_FEAT_EN] &= ~SATA_PMP_FEAT_NOTIFY;
 
-		rc = sata_pmp_write(dev->link, SATA_PMP_GSCR_FEAT_EN,
-				    gscr[SATA_PMP_GSCR_FEAT_EN]);
-		if (rc) {
+		err_mask = sata_pmp_write(dev->link, SATA_PMP_GSCR_FEAT_EN,
+					  gscr[SATA_PMP_GSCR_FEAT_EN]);
+		if (err_mask) {
+			rc = -EIO;
 			reason = "failed to write GSCR_FEAT_EN";
 			goto fail;
 		}
@@ -447,7 +417,8 @@ static int sata_pmp_configure(struct ata_device *dev, int print_info)
 
  fail:
 	ata_dev_printk(dev, KERN_ERR,
-		       "failed to configure Port Multiplier (%s)\n", reason);
+		       "failed to configure Port Multiplier (%s, Emask=0x%x)\n",
+		       reason, err_mask);
 	return rc;
 }
 
@@ -812,13 +783,14 @@ static int sata_pmp_revalidate(struct ata_device *dev, unsigned int new_class)
  */
 static int sata_pmp_revalidate_quick(struct ata_device *dev)
 {
+	unsigned int err_mask;
 	u32 prod_id;
-	int rc;
 
-	rc = sata_pmp_read(dev->link, SATA_PMP_GSCR_PROD_ID, &prod_id);
-	if (rc) {
-		ata_dev_printk(dev, KERN_ERR, "failed to read PMP product ID\n");
-		return rc;
+	err_mask = sata_pmp_read(dev->link, SATA_PMP_GSCR_PROD_ID, &prod_id);
+	if (err_mask) {
+		ata_dev_printk(dev, KERN_ERR, "failed to read PMP product ID "
+			       "(Emask=0x%x)\n", err_mask);
+		return -EIO;
 	}
 
 	if (prod_id != dev->gscr[SATA_PMP_GSCR_PROD_ID]) {
@@ -1049,6 +1021,7 @@ static int sata_pmp_eh_recover(struct ata_port *ap,
 	struct ata_eh_context *pmp_ehc = &pmp_link->eh_context;
 	struct ata_link *link;
 	struct ata_device *dev;
+	unsigned int err_mask;
 	u32 gscr_error, sntf;
 	int cnt, rc;
 
@@ -1107,20 +1080,22 @@ static int sata_pmp_eh_recover(struct ata_port *ap,
 	if (pmp_dev->flags & ATA_DFLAG_AN) {
 		pmp_dev->gscr[SATA_PMP_GSCR_FEAT_EN] |= SATA_PMP_FEAT_NOTIFY;
 
-		rc = sata_pmp_write(pmp_dev->link, SATA_PMP_GSCR_FEAT_EN,
-				    pmp_dev->gscr[SATA_PMP_GSCR_FEAT_EN]);
-		if (rc) {
-			ata_dev_printk(pmp_dev, KERN_ERR,
-				       "failed to write PMP_FEAT_EN\n");
+		err_mask = sata_pmp_write(pmp_dev->link, SATA_PMP_GSCR_FEAT_EN,
+					  pmp_dev->gscr[SATA_PMP_GSCR_FEAT_EN]);
+		if (err_mask) {
+			ata_dev_printk(pmp_dev, KERN_ERR, "failed to write "
+				       "PMP_FEAT_EN (Emask=0x%x)\n", err_mask);
+			rc = -EIO;
 			goto pmp_fail;
 		}
 	}
 
 	/* check GSCR_ERROR */
-	rc = sata_pmp_read(pmp_link, SATA_PMP_GSCR_ERROR, &gscr_error);
-	if (rc) {
-		ata_dev_printk(pmp_dev, KERN_ERR,
-			       "failed to read PMP_GSCR_ERROR\n");
+	err_mask = sata_pmp_read(pmp_link, SATA_PMP_GSCR_ERROR, &gscr_error);
+	if (err_mask) {
+		ata_dev_printk(pmp_dev, KERN_ERR, "failed to read "
+			       "PMP_GSCR_ERROR (Emask=0x%x)\n", err_mask);
+		rc = -EIO;
 		goto pmp_fail;
 	}