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AHCI SATA vendor update from VIA

PATCH In review Jeff Garzik 3 participants 7 messages Dec 12, 2005 – Mar 23, 2006

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#0 lore raw

PATCH 1/1 AHCI SATA vendor update from VIA

I received this ahci.c patch from VIA, and pass it on for review, comment, and testing.

This patch won't go in as-is, because it does too much special casing. But until we get around to that, people with VIA controllers probably want this...

Jeff

ahci.c renamed from ahci.c.orig +289 -0
@@ -59,6 +59,7 @@
 	RX_FIS_D2H_REG		= 0x40,	/* offset of D2H Register FIS data */
 
 	board_ahci		= 0,
+	board_via_ahci		= 1,
 
 	/* global controller registers */
 	HOST_CAP		= 0x00, /* host capabilities */
@@ -126,6 +127,7 @@
 	PORT_CMD_LIST_ON	= (1 << 15), /* cmd list DMA engine running */
 	PORT_CMD_FIS_ON		= (1 << 14), /* FIS DMA engine running */
 	PORT_CMD_FIS_RX		= (1 << 4), /* Enable FIS receive DMA engine */
+	PORT_CMD_CLO		= (1 << 3), /* CLO */
 	PORT_CMD_POWER_ON	= (1 << 2), /* Power up device */
 	PORT_CMD_SPIN_UP	= (1 << 1), /* Spin up device */
 	PORT_CMD_START		= (1 << 0), /* Enable port DMA engine */
@@ -183,6 +185,14 @@
 static u8 ahci_check_err(struct ata_port *ap);
 static inline int ahci_host_intr(struct ata_port *ap, struct ata_queued_cmd *qc);
 
+static int via_ahci_qc_issue(struct ata_queued_cmd *qc);
+static void via_ahci_phy_reset(struct ata_port *ap);
+static void via_ahci_port_stop(struct ata_port *ap);
+static int via_ahci_softreset(struct ata_port *ap);
+static unsigned int via_ata_busy_sleep (struct ata_port *ap,
+				    unsigned long tmout_pat,
+			    	    unsigned long tmout);
+
 static Scsi_Host_Template ahci_sht = {
 	.module			= THIS_MODULE,
 	.name			= DRV_NAME,
@@ -231,6 +241,35 @@
 	.host_stop		= ahci_host_stop,
 };
 
+static struct ata_port_operations via_ahci_ops = {
+	.port_disable		= ata_port_disable,
+
+	.check_status		= ahci_check_status,
+	.check_altstatus	= ahci_check_status,
+	.check_err		= ahci_check_err,
+	.dev_select		= ata_noop_dev_select,
+
+	.tf_read		= ahci_tf_read,
+
+
+	.qc_prep		= ahci_qc_prep,
+
+	.eng_timeout		= ahci_eng_timeout,
+
+	.irq_handler		= ahci_interrupt,
+	.irq_clear		= ahci_irq_clear,
+
+	.scr_read		= ahci_scr_read,
+	.scr_write		= ahci_scr_write,
+
+	.port_start		= ahci_port_start,
+	.host_stop		= ahci_host_stop,
+
+	.phy_reset		= via_ahci_phy_reset,
+	.qc_issue		= via_ahci_qc_issue,
+	.port_stop		= via_ahci_port_stop,
+};
+
 static struct ata_port_info ahci_port_info[] = {
 	/* board_ahci */
 	{
@@ -242,6 +281,16 @@
 		.udma_mask	= 0x7f, /* udma0-6 ; FIXME */
 		.port_ops	= &ahci_ops,
 	},
+	/* board_via_ahci */
+	{
+		.sht		= &ahci_sht,
+		.host_flags	= ATA_FLAG_SATA | ATA_FLAG_NO_LEGACY |
+				  ATA_FLAG_SRST | ATA_FLAG_MMIO |
+				  ATA_FLAG_PIO_DMA,
+		.pio_mask	= 0x03, /* pio3-4 */
+		.udma_mask	= 0x7f, /* udma0-6 ; FIXME */
+		.port_ops	= &via_ahci_ops,
+	},
 };
 
 static struct pci_device_id ahci_pci_tbl[] = {
@@ -263,6 +312,8 @@
 	  board_ahci }, /* ESB2 */
 	{ PCI_VENDOR_ID_INTEL, 0x2683, PCI_ANY_ID, PCI_ANY_ID, 0, 0,
 	  board_ahci }, /* ESB2 */
+	{ PCI_VENDOR_ID_VIA, 0x3349, PCI_ANY_ID, PCI_ANY_ID, 0, 0,
+	  board_via_ahci }, /* VT8251*/
 	{ }	/* terminate list */
 };
 
@@ -1049,6 +1100,244 @@
 	return rc;
 }
 
+/* START: patch code for VIA VT8251 ahci controller */
+
+static int via_ahci_softreset(struct ata_port *ap)
+{
+	void __iomem *port_mmio = (void __iomem *) ap->ioaddr.cmd_addr;
+	struct ahci_port_priv *pp = ap->private_data;
+	u32 tmp,i;
+	u8 *fisbuf;
+
+	VPRINTK("ENTER\n");
+
+	writel(0x00000000, port_mmio + PORT_IRQ_MASK);  /*disable interrupt */
+	readl (port_mmio + PORT_IRQ_MASK);  /* flush */
+
+	/* prepare the software-reset commands */
+
+	/* prepare first command header */
+	memset(pp->cmd_slot, 0, 32);
+	pp->cmd_slot[0].opts = 0x00000505;
+	pp->cmd_slot[0].status = 0;
+	pp->cmd_slot[0].tbl_addr = cpu_to_le32(pp->cmd_tbl_dma & 0xffffffff);
+	pp->cmd_slot[0].tbl_addr_hi = cpu_to_le32((pp->cmd_tbl_dma >> 16) >> 16);
+
+	/* prepare CMDFIS struct */
+	fisbuf = pp->cmd_tbl;
+	memset(fisbuf, 0, 64);
+	fisbuf[0] = 0x27;
+	fisbuf[7] = 0xa0;
+	fisbuf[15] = 0x04;
+	
+	/* trigger the commands */
+	writel(0x1, port_mmio + PORT_CMD_ISSUE);
+	readl (port_mmio + PORT_CMD_ISSUE); /* flush */
+
+	udelay(20);
+    /* wait command complete */
+	for (i = 0; i < 2000; i++) {
+		tmp = readl(port_mmio + PORT_CMD_ISSUE);
+		if ((tmp & 1) == 0) break;
+		msleep(20);
+	}
+
+	if (i == 2000) {
+		printk(KERN_WARNING "TimeOut for Wait Command complete\n");
+		return 1;
+	}
+
+	/* prepare second command header */
+	pp->cmd_slot[0].opts = 0x00000005;
+	pp->cmd_slot[0].status = 0;
+	pp->cmd_slot[0].tbl_addr = cpu_to_le32(pp->cmd_tbl_dma & 0xffffffff);
+	pp->cmd_slot[0].tbl_addr_hi = cpu_to_le32((pp->cmd_tbl_dma >> 16) >> 16);
+
+	fisbuf = pp->cmd_tbl;
+	memset(fisbuf, 0, 64);
+	fisbuf[0] = 0x27;
+	fisbuf[7] = 0xa0;
+	fisbuf[15] = 0x00;
+
+	/* trigger the commands */
+	writel(0x1, port_mmio + PORT_CMD_ISSUE);
+	readl (port_mmio + PORT_CMD_ISSUE); /* flush */
+
+	udelay(20);
+    /* wait command complete */
+	for (i = 0; i < 2000; i++) {
+		tmp = readl(port_mmio + PORT_CMD_ISSUE);
+		if ((tmp & 1) == 0) break;
+		msleep(20);
+	}
+
+	if (i == 2000) {
+		printk(KERN_WARNING "TimeOut for Wait Command complete\n");
+		return 1;
+	}
+
+	// enable port interrupt
+	writel(0xffffffff, port_mmio + PORT_IRQ_MASK);
+	readl (port_mmio + PORT_IRQ_MASK);  /* flush */
+
+	return 0;
+}
+
+static unsigned int via_ata_busy_sleep (struct ata_port *ap,
+				    unsigned long tmout_pat,
+			    	    unsigned long tmout)
+{
+	unsigned long timer_start, timeout;
+	u8 status;
+
+	status = ata_busy_wait(ap, ATA_BUSY, 300);
+	timer_start = jiffies;
+	timeout = timer_start + tmout_pat;
+	while ((status & ATA_BUSY) && (time_before(jiffies, timeout))) {
+		msleep(50);
+		status = ata_busy_wait(ap, ATA_BUSY, 3);
+	}
+
+	if (status & ATA_BUSY)
+		printk(KERN_WARNING "ata%u is slow to respond, "
+		       "please be patient\n", ap->id);
+
+	timeout = timer_start + tmout;
+	while ((status & ATA_BUSY) && (time_before(jiffies, timeout))) {
+		msleep(50);
+		status = ata_chk_status(ap);
+	}
+
+	if (status & ATA_BUSY) {
+		printk(KERN_ERR "ata%u failed to respond (%lu secs)\n",
+		       ap->id, tmout / HZ);
+		return 1;
+	}
+
+	return 0;
+}
+
+static void via_ahci_phy_reset(struct ata_port *ap)
+{
+	void __iomem *port_mmio = (void __iomem *) ap->ioaddr.cmd_addr;
+	struct ata_taskfile tf;
+	struct ata_device *dev = &ap->device[0];
+	u32 tmp;
+
+	u32 sstatus,i;
+	unsigned long timeout = jiffies + (HZ * 5);
+	u8 tmp_status;
+	
+	if (ap->flags & ATA_FLAG_SATA_RESET) {
+		/* issue phy wake/reset */
+		scr_write_flush(ap, SCR_CONTROL, 0x301);
+		udelay(400);			/* FIXME: a guess */
+	}
+	scr_write_flush(ap, SCR_CONTROL, 0x300); /* phy wake/clear reset */
+
+	/* wait for phy to become ready, if necessary */
+	do {
+		msleep(200);
+		sstatus = scr_read(ap, SCR_STATUS);
+		if ((sstatus & 0xf) != 1)
+			break;
+	} while (time_before(jiffies, timeout));
+
+	/* TODO: phy layer with polling, timeouts, etc. */
+	if (sata_dev_present(ap))
+		ata_port_probe(ap);
+	else {
+		sstatus = scr_read(ap, SCR_STATUS);
+		printk(KERN_INFO "ata%u: no device found (phy stat %08x)\n",
+		       ap->id, sstatus);
+		ata_port_disable(ap);
+	}
+
+	if (ap->flags & ATA_FLAG_PORT_DISABLED)
+		return;
+
+	/*Fix the VIA busy bug by a software reset*/
+	for (i = 0; i < 100; i++) {
+		tmp_status = ap->ops->check_status(ap);
+		if ((tmp_status & ATA_BUSY) == 0) break;
+		msleep(10);
+	}
+
+	if ((tmp_status & ATA_BUSY)) {
+		DPRINTK("Busy after CommReset, do softreset...\n"); 
+		/*set the PxCMD.CLO bit to clear BUSY and DRQ, to make the reset command sent out*/
+		tmp = readl(port_mmio + PORT_CMD);
+		tmp |= PORT_CMD_CLO;
+		writel(tmp, port_mmio + PORT_CMD);
+		readl(port_mmio + PORT_CMD); /* flush */
+
+		if (via_ahci_softreset(ap)) {
+			printk(KERN_WARNING "softreset failed\n");
+			return;
+		}
+	}
+
+	if (via_ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT)) {
+		ata_port_disable(ap);
+		return;
+	}
+
+	ap->cbl = ATA_CBL_SATA;
+
+	if (ap->flags & ATA_FLAG_PORT_DISABLED)
+		return;
+
+	tmp = readl(port_mmio + PORT_SIG);
+	tf.lbah		= (tmp >> 24)	& 0xff;
+	tf.lbam		= (tmp >> 16)	& 0xff;
+	tf.lbal		= (tmp >> 8)	& 0xff;
+	tf.nsect	= (tmp)		& 0xff;
+
+	dev->class = ata_dev_classify(&tf);
+	if (!ata_dev_present(dev))
+		ata_port_disable(ap);
+
+}
+
+static int via_ahci_qc_issue(struct ata_queued_cmd *qc)
+{
+	struct ata_port *ap = qc->ap;
+	void *port_mmio = (void *) ap->ioaddr.cmd_addr;
+
+    if (qc &&
+        qc->tf.command == ATA_CMD_SET_FEATURES &&
+        qc->tf.feature == SETFEATURES_XFER) {
+        /* skip set xfer mode process */
+
+		ata_qc_complete(qc, 0);
+		qc = NULL;
+        return 0;
+    }
+
+	writel(1, port_mmio + PORT_CMD_ISSUE);
+	readl(port_mmio + PORT_CMD_ISSUE);	/* flush */
+
+	return 0;
+}
+
+static void via_ahci_port_stop(struct ata_port *ap)
+{
+	struct device *dev = ap->host_set->dev;
+	struct ahci_port_priv *pp = ap->private_data;
+
+	/* spec says 500 msecs for each PORT_CMD_{START,FIS_RX} bit, so
+	 * this is slightly incorrect.
+	 */
+	msleep(500);
+
+	ap->private_data = NULL;
+	dma_free_coherent(dev, AHCI_PORT_PRIV_DMA_SZ,
+			  pp->cmd_slot, pp->cmd_slot_dma);
+	kfree(pp);
+	ata_port_stop(ap);
+}
+
+/* END: patch code for VIA VT8251 ahci controller */
 
 static int __init ahci_init(void)
 {
#1 lore raw
Quoted 8 lines · On Sun, 11 Dec 2005 23:09:54 -0500 Jeff Garzik wrote:

I received this ahci.c patch from VIA, and pass it on for review, comment, and testing.

This patch won't go in as-is, because it does too much special casing. But until we get around to that, people with VIA controllers probably want this...

Jeff

What is needed to get the VT8251 support into the kernel tree?

I have looked at the patch, and it basically does three things:

1) Apparently the VT8251 hardware does not like the standard reset sequence performed by __sata_phy_reset() - the phy seems to become ready, but the ATA_BUSY bit never goes off. So the patch authors just duplicated ahci_phy_reset(), inserted the whole code of __sata_phy_reset() in there, and added this part before the ata_busy_sleep() call:

+ /*Fix the VIA busy bug by a software reset*/
+ for (i = 0; i < 100; i++) {
+ tmp_status = ap->ops->check_status(ap);
+ if ((tmp_status & ATA_BUSY) == 0) break;
+ msleep(10);
+ }
+
+ if ((tmp_status & ATA_BUSY)) {
+ DPRINTK("Busy after CommReset, do softreset...\n");
+ /*set the PxCMD.CLO bit to clear BUSY and DRQ, to make the reset command sent out*/
+ tmp = readl(port_mmio + PORT_CMD);
+ tmp |= PORT_CMD_CLO;
+ writel(tmp, port_mmio + PORT_CMD);
+ readl(port_mmio + PORT_CMD); /* flush */
+
+ if (via_ahci_softreset(ap)) {
+ printk(KERN_WARNING "softreset failed\n");
+ return;
+ }
+ }

Now, if this is really a chip bug, we don't have any choice except adding this workaround, but obviously not in this way. What do you think about splitting __sata_phy_reset() in two parts - __sata_phy_reset_start() (everything up to the point where ata_busy_sleep() is called) and __sata_phy_reset_end() (ata_busy_sleep() and the rest), so that the low-level driver could insert its own code between these parts? Or should a hook for this be added to ->ops instead?

2) via_ahci_qc_issue really just filters out the SETFEATURES_XFER command; only VIA can tell why this is needed, and is there a better way to do this. However, at least some duplicated code could be removed easily:

static int via_ahci_qc_issue(struct ata_queued_cmd *qc)

{
	if (qc && qc->tf.command == ATA_CMD_SET_FEATURES &&
	    qc->tf.feature == SETFEATURES_XFER) {
		/* skip set xfer mode process */
		ata_qc_complete(qc);
		return 0;
	}
	return ahci_qc_issue(qc);
}

Would this be acceptable?

3) What via_ahci_port_stop() does, I just don't understand - it is basically a copy of ahci_port_stop() at that time, but with clearing of the PORT_CMD bits removed - so nothing is stopped actually. Again, only VIA can tell why is this needed, but this part of the patch looks like a bug.

Geoff Rivell (CC'ed) tried to update the patch for 2.6.15:

http://grivell.home.comcast.net/via_ahci.patch

However, that patch does some things in a different order from the VIA code - it calls via_ahci_softreset() before __sata_phy_reset(), which does not seem safe to me. Geoff, does this really work?

#2 lore raw
Quoted 1 line · Sergey Vlasov

What is needed to get the VT8251 support into the kernel tree?

1) Doing what you are doing: asking questions like this. :)

2) Watching Tejun Heo's reset work. He already has an AHCI soft reset patch, and the VIA AHCI work really depends on this.

Quoted 28 lines

I have looked at the patch, and it basically does three things:

1) Apparently the VT8251 hardware does not like the standard reset sequence performed by __sata_phy_reset() - the phy seems to become ready, but the ATA_BUSY bit never goes off. So the patch authors just duplicated ahci_phy_reset(), inserted the whole code of __sata_phy_reset() in there, and added this part before the ata_busy_sleep() call:

ahci.c renamed from ahci.c.orig +19 -0
+	/*Fix the VIA busy bug by a software reset*/
+	for (i = 0; i < 100; i++) {
+		tmp_status = ap->ops->check_status(ap);
+		if ((tmp_status & ATA_BUSY) == 0) break;
+		msleep(10);
+	}
+
+	if ((tmp_status & ATA_BUSY)) {
+		DPRINTK("Busy after CommReset, do softreset...\n"); 
+		/*set the PxCMD.CLO bit to clear BUSY and DRQ, to make the reset command sent out*/
+		tmp = readl(port_mmio + PORT_CMD);
+		tmp |= PORT_CMD_CLO;
+		writel(tmp, port_mmio + PORT_CMD);
+		readl(port_mmio + PORT_CMD); /* flush */
+
+		if (via_ahci_softreset(ap)) {
+			printk(KERN_WARNING "softreset failed\n");
+			return;
+		}

ahci.c

Quoted 10 lines
ahci.c renamed from ahci.c.orig +1 -0
+	}
 
   Now, if this is really a chip bug, we don't have any choice except
   adding this workaround, but obviously not in this way.  What do you
   think about splitting __sata_phy_reset() in two parts -
   __sata_phy_reset_start() (everything up to the point where
   ata_busy_sleep() is called) and __sata_phy_reset_end()
   (ata_busy_sleep() and the rest), so that the low-level driver could
   insert its own code between these parts?  Or should a hook for this
   be added to ->ops instead?

Tejun's stuff broke up this sequence, so it should be much easier to utilize his new reset code (in libata-dev.git#upstream, queued for 2.6.17).

Quoted 16 lines

2) via_ahci_qc_issue really just filters out the SETFEATURES_XFER command; only VIA can tell why this is needed, and is there a better way to do this. However, at least some duplicated code could be removed easily:

static int via_ahci_qc_issue(struct ata_queued_cmd *qc)

{
	if (qc && qc->tf.command == ATA_CMD_SET_FEATURES &&
	    qc->tf.feature == SETFEATURES_XFER) {
		/* skip set xfer mode process */
		ata_qc_complete(qc);
		return 0;
	}
	return ahci_qc_issue(qc);
}
Quoted 1 line

Would this be acceptable?

I wonder first if this actually solves some problems. I would prefer to -not- do this, and see what happens.

Quoted 5 lines

3) What via_ahci_port_stop() does, I just don't understand - it is basically a copy of ahci_port_stop() at that time, but with clearing of the PORT_CMD bits removed - so nothing is stopped actually. Again, only VIA can tell why is this needed, but this part of the patch looks like a bug.

As your instinct seems to be, I would prefer to avoid this change if possible.

Jeff

#3 lore raw

Hello,

Quoted 7 lines · Jeff Garzik
Quoted 1 line · Sergey Vlasov

What is needed to get the VT8251 support into the kernel tree?

1) Doing what you are doing: asking questions like this. :)

2) Watching Tejun Heo's reset work. He already has an AHCI soft reset patch, and the VIA AHCI work really depends on this.

BTW, what happened to AHCI softreset patch. It got acked[1], but it has not made into the tree yet. Do you want me to regenerate it against the current tree? Or is there anything holding it from going into the tree?

Quoted 31 lines
Quoted 31 lines

I have looked at the patch, and it basically does three things:

1) Apparently the VT8251 hardware does not like the standard reset sequence performed by __sata_phy_reset() - the phy seems to become ready, but the ATA_BUSY bit never goes off. So the patch authors just duplicated ahci_phy_reset(), inserted the whole code of __sata_phy_reset() in there, and added this part before the ata_busy_sleep() call:

ahci.c renamed from ahci.c.orig +9 -0
+    /*Fix the VIA busy bug by a software reset*/
+    for (i = 0; i < 100; i++) {
+        tmp_status = ap->ops->check_status(ap);
+        if ((tmp_status & ATA_BUSY) == 0) break;
+        msleep(10);
+    }
+
+    if ((tmp_status & ATA_BUSY)) {
+        DPRINTK("Busy after CommReset, do softreset...\n"); +        

/*set the PxCMD.CLO bit to clear BUSY and DRQ, to make the reset command sent out*/

ahci.c renamed from ahci.c.orig +10 -0
+        tmp = readl(port_mmio + PORT_CMD);
+        tmp |= PORT_CMD_CLO;
+        writel(tmp, port_mmio + PORT_CMD);
+        readl(port_mmio + PORT_CMD); /* flush */
+
+        if (via_ahci_softreset(ap)) {
+            printk(KERN_WARNING "softreset failed\n");
+            return;
+        }
+    }
Quoted 11 lines
Quoted 8 lines

Now, if this is really a chip bug, we don't have any choice except adding this workaround, but obviously not in this way. What do you think about splitting __sata_phy_reset() in two parts - __sata_phy_reset_start() (everything up to the point where ata_busy_sleep() is called) and __sata_phy_reset_end() (ata_busy_sleep() and the rest), so that the low-level driver could insert its own code between these parts? Or should a hook for this be added to ->ops instead?

Tejun's stuff broke up this sequence, so it should be much easier to utilize his new reset code (in libata-dev.git#upstream, queued for 2.6.17).

If hardreset never works on via ahci, simply omitting hardreset in ahci_probe_reset() routine for that controller should do the job (with the AHCI softreset patch applied of course).

Signature · 3 lines
tejun

[1] http://thread.gmane.org/gmane.linux.ide/7952
#4 lore raw
Quoted 9 lines · Tejun Heo

Hello,

Quoted 5 lines · Jeff Garzik
Quoted 1 line · Sergey Vlasov

What is needed to get the VT8251 support into the kernel tree?

Quoted 6 lines
Quoted 4 lines

1) Doing what you are doing: asking questions like this. :)

2) Watching Tejun Heo's reset work. He already has an AHCI soft reset patch, and the VIA AHCI work really depends on this.

BTW, what happened to AHCI softreset patch. It got acked[1], but it has not made into the tree yet. Do you want me to regenerate it against the current tree? Or is there anything holding it from going into the tree?

Please resend, the only pending patch I have from you is the ATA transport class patch (thanks for doing that BTW), which is on hold waiting for SCSI updates.

Jeff

#5 lore raw

PATCH 1/1 ahci: add softreset

Now that libata is smart enought to handle both soft and hard resets, add softreset method.

---

There has been no relevant change for AHCI since last post. The following patch is identical to the last posting.

 ahci.c |  135 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 134 insertions(+), 1 deletion(-)
drivers/scsi/ahci.c +134 -1
@@ -513,6 +513,138 @@ static void ahci_fill_cmd_slot(struct ah
 	pp->cmd_slot[0].tbl_addr_hi = cpu_to_le32((pp->cmd_tbl_dma >> 16) >> 16);
 }
 
+static int ahci_poll_register(void __iomem *reg, u32 mask, u32 val,
+			      unsigned long interval_msec,
+			      unsigned long timeout_msec)
+{
+	unsigned long timeout;
+	u32 tmp;
+
+	timeout = jiffies + (timeout_msec * HZ) / 1000;
+	do {
+		tmp = readl(reg);
+		if ((tmp & mask) == val)
+			return 0;
+		msleep(interval_msec);
+	} while (time_before(jiffies, timeout));
+
+	return -1;
+}
+
+static int ahci_softreset(struct ata_port *ap, int verbose, unsigned int *class)
+{
+	struct ahci_host_priv *hpriv = ap->host_set->private_data;
+	struct ahci_port_priv *pp = ap->private_data;
+	void __iomem *mmio = ap->host_set->mmio_base;
+	void __iomem *port_mmio = ahci_port_base(mmio, ap->port_no);
+	const u32 cmd_fis_len = 5; /* five dwords */
+	const char *reason = NULL;
+	struct ata_taskfile tf;
+	u8 *fis;
+	int rc;
+
+	DPRINTK("ENTER\n");
+
+	/* prepare for SRST (AHCI-1.1 10.4.1) */
+	rc = ahci_stop_engine(ap);
+	if (rc) {
+		reason = "failed to stop engine";
+		goto fail_restart;
+	}
+
+	/* check BUSY/DRQ, perform Command List Override if necessary */
+	ahci_tf_read(ap, &tf);
+	if (tf.command & (ATA_BUSY | ATA_DRQ)) {
+		u32 tmp;
+
+		if (!(hpriv->cap & HOST_CAP_CLO)) {
+			rc = -EIO;
+			reason = "port busy but no CLO";
+			goto fail_restart;
+		}
+
+		tmp = readl(port_mmio + PORT_CMD);
+		tmp |= PORT_CMD_CLO;
+		writel(tmp, port_mmio + PORT_CMD);
+		readl(port_mmio + PORT_CMD); /* flush */
+
+		if (ahci_poll_register(port_mmio + PORT_CMD, PORT_CMD_CLO, 0x0,
+				       1, 500)) {
+			rc = -EIO;
+			reason = "CLO failed";
+			goto fail_restart;
+		}
+	}
+
+	/* restart engine */
+	ahci_start_engine(ap);
+
+	ata_tf_init(ap, &tf, 0);
+	fis = pp->cmd_tbl;
+
+	/* issue the first D2H Register FIS */
+	ahci_fill_cmd_slot(pp, cmd_fis_len | AHCI_CMD_RESET | AHCI_CMD_CLR_BUSY);
+
+	tf.ctl |= ATA_SRST;
+	ata_tf_to_fis(&tf, fis, 0);
+	fis[1] &= ~(1 << 7);	/* turn off Command FIS bit */
+
+	writel(1, port_mmio + PORT_CMD_ISSUE);
+	readl(port_mmio + PORT_CMD_ISSUE);	/* flush */
+
+	if (ahci_poll_register(port_mmio + PORT_CMD_ISSUE, 0x1, 0x0, 1, 500)) {
+		rc = -EIO;
+		reason = "1st FIS failed";
+		goto fail;
+	}
+
+	/* spec says at least 5us, but be generous and sleep for 1ms */
+	msleep(1);
+
+	/* issue the second D2H Register FIS */
+	ahci_fill_cmd_slot(pp, cmd_fis_len);
+
+	tf.ctl &= ~ATA_SRST;
+	ata_tf_to_fis(&tf, fis, 0);
+	fis[1] &= ~(1 << 7);	/* turn off Command FIS bit */
+
+	writel(1, port_mmio + PORT_CMD_ISSUE);
+	readl(port_mmio + PORT_CMD_ISSUE);	/* flush */
+
+	/* spec mandates ">= 2ms" before checking status.
+	 * We wait 150ms, because that was the magic delay used for
+	 * ATAPI devices in Hale Landis's ATADRVR, for the period of time
+	 * between when the ATA command register is written, and then
+	 * status is checked.  Because waiting for "a while" before
+	 * checking status is fine, post SRST, we perform this magic
+	 * delay here as well.
+	 */
+	msleep(150);
+
+	*class = ATA_DEV_NONE;
+	if (sata_dev_present(ap)) {
+		if (ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT)) {
+			rc = -EIO;
+			reason = "device not ready";
+			goto fail;
+		}
+		*class = ahci_dev_classify(ap);
+	}
+
+	DPRINTK("EXIT, class=%u\n", *class);
+	return 0;
+
+ fail_restart:
+	ahci_start_engine(ap);
+ fail:
+	if (verbose)
+		printk(KERN_ERR "ata%u: softreset failed (%s)\n",
+		       ap->id, reason);
+	else
+		DPRINTK("EXIT, rc=%d reason=\"%s\"\n", rc, reason);
+	return rc;
+}
+
 static int ahci_hardreset(struct ata_port *ap, int verbose, unsigned int *class)
 {
 	int rc;
@@ -553,7 +685,8 @@ static void ahci_postreset(struct ata_po
 
 static int ahci_probe_reset(struct ata_port *ap, unsigned int *classes)
 {
-	return ata_drive_probe_reset(ap, NULL, NULL, ahci_hardreset,
+	return ata_drive_probe_reset(ap, ata_std_probeinit,
+				     ahci_softreset, ahci_hardreset,
 				     ahci_postreset, classes);
 }
 
author Applied
#6 lore raw

Re: [PATCH] ahci: add softreset

Quoted 4 lines · Tejun Heo

Now that libata is smart enought to handle both soft and hard resets, add softreset method.

applied