From: David Milburn <dmilburn@redhat.com>
Date: Fri, 28 Nov 2008 09:01:18 -0600
Subject: [ata] libata: sata_nv hard reset mcp55
Message-id: 20081128150118.GA5688@dhcp-210.hsv.redhat.com
O-Subject: [RHEL5.3 PATCH] libata: sata_nv hardreset mcp55
Bugzilla: 473152
RH-Acked-by: Jeff Garzik <jgarzik@redhat.com>

This patch resolves BZ 473152, Sun reports -124.el5 sata_nv
may not recognize drive when using the MCP55 chipset. They
have verified a -124.el5 test kernel built with this patch.

ata_wait_idle reports abnormal status for each port and
the status of each link is down.

ata_eh_recover: ENTER
__ata_port_freeze: ata1 port frozen
sata_link_hardreset: ENTER
sata_link_hardreset: EXIT, rc=0
sata_sff_hardreset: EXIT, class=0
ata1: abnormal Status 0x7F
ata_eh_thaw_port: ata1 port thawed
ata_std_postreset: ENTER
ata1: SATA link down (SStatus 100 SControl 300)

This patch is a net backport of these 3 commits fixing
upstream problem where hardreset may succeed but link
doesn't come online.

commit 2fd673ecf0378ddeeeb87b3605e50212e0c0ddc6
Author: Tejun Heo <tj@kernel.org>
Date:   Fri Aug 29 16:13:12 2008 +0200

    sata_nv: disable hardreset for generic

    of them being unifying probing, hotplug and EH reset paths uniform.
    Previously, broken hardreset could go unnoticed as it wasn't used
    during probing but when something goes wrong or after hotplug the
    problem will surface and bite hard.

    OSDL bug 11195 reports that sata_nv generic flavor falls into this
    category.  Hardreset itself succeeds but PHY stays offline after
    hardreset.  I tried longer debounce timing but the result was the
    same.

      http://bugzilla.kernel.org/show_bug.cgi?id=11195

    So, it seems we'll have to drop hardreset from the generic flavor.

commit 4c1eb90a0908c0c60db2169dce08fb672e7582f1
Author: Tejun Heo <tj@kernel.org>
Date:   Sun Sep 28 07:39:01 2008 +0900

    sata_nv: reinstate nv_hardreset() for non generic controllers

    Commit 2fd673ecf0378ddeeeb87b3605e50212e0c0ddc6 which tried to remove
    hardreset for generic accidentally removed it for all flavors as all
    others were inheriting from nv_generic_ops.  This patch reinstates
    nv_hardreset() and puts it into nv_common_ops which all flavors
    inherit from.  nv_generic_ops now inherits from nv_common_ops and
    overrides .hardreset to ATA_OP_NULL.

    While at it, explain why nv_hardreset and ATA_OP_NULL override are
    necessary.

commit 3c324283e6cdb79210cf7975c3e40d3ba3e672b2
Author: Tejun Heo <tj@kernel.org>
Date:   Mon Nov 3 12:37:49 2008 +0900

    sata_nv: fix generic, nf2/3 detection regression

    All three flavors of sata_nv's are different in how their hardreset
    behaves.

    * generic: Hardreset is not reliable.  Link often doesn't come online
      after hardreset.

    * nf2/3: A little bit better - link comes online with longer debounce
      timing.  However, nf2/3 can't reliable wait for the first D2H
      Register FIS, so it can't wait for device readiness or classify the
      device after hardreset.  Follow-up SRST required.

    * ck804: Hardreset finally works.

    The core layer change to prefer hardreset and follow up changes
    exposed the above issues and caused various detection regressions for
    all three flavors.  This patch, hopefully, fixes all the known issues
    and should make sata_nv error handling more reliable.

Currently building all arches thru brew

https://brewweb.devel.redhat.com/taskinfo?taskID=1591045

 drivers/ata/sata_nv.c |   62 ++++++++++++++++++++++++++++++-------------------
 1 files changed, 38 insertions(+), 24 deletions(-)

diff --git a/drivers/ata/sata_nv.c b/drivers/ata/sata_nv.c
index e620ca1..b19fce7 100644
--- a/drivers/ata/sata_nv.c
+++ b/drivers/ata/sata_nv.c
@@ -310,10 +310,10 @@ static int nv_scr_write(struct ata_port *ap, unsigned int sc_reg, u32 val);
 
 static void nv_nf2_freeze(struct ata_port *ap);
 static void nv_nf2_thaw(struct ata_port *ap);
+static int nv_nf2_hardreset(struct ata_link *link, unsigned int *class,
+			    unsigned long deadline);
 static void nv_ck804_freeze(struct ata_port *ap);
 static void nv_ck804_thaw(struct ata_port *ap);
-static int nv_hardreset(struct ata_link *link, unsigned int *class,
-			unsigned long deadline);
 static int nv_adma_slave_config(struct scsi_device *sdev);
 static int nv_adma_check_atapi_dma(struct ata_queued_cmd *qc);
 static void nv_adma_qc_prep(struct ata_queued_cmd *qc);
@@ -408,28 +408,46 @@ static struct scsi_host_template nv_swncq_sht = {
 	.slave_configure	= nv_swncq_slave_config,
 };
 
+static struct ata_port_operations nv_common_ops = {
+	.inherits               = &ata_bmdma_port_ops,
+        .scr_read               = nv_scr_read,
+        .scr_write              = nv_scr_write,
+};
+
+/* OSDL bz11195 reports that link doesn't come online after hardreset
+ * on generic nv's and there have been several other similar reports
+ * on linux-ide.  Disable hardreset for generic nv's.
+ */
 static struct ata_port_operations nv_generic_ops = {
-	.inherits		= &ata_bmdma_port_ops,
-	.hardreset		= nv_hardreset,
-	.scr_read		= nv_scr_read,
-	.scr_write		= nv_scr_write,
+	.inherits		= &nv_common_ops,
+	.hardreset		= ATA_OP_NULL,
 };
 
+/* OSDL bz3352 reports that nf2/3 controllers can't determine device
+ * signature reliably.  Also, the following thread reports detection
+ * failure on cold boot with the standard debouncing timing.
+ *
+ * http://thread.gmane.org/gmane.linux.ide/34098
+ *
+ * Debounce with hotplug timing and request follow-up SRST.
+ */
 static struct ata_port_operations nv_nf2_ops = {
-	.inherits		= &nv_generic_ops,
+	.inherits		= &nv_common_ops,
 	.freeze			= nv_nf2_freeze,
 	.thaw			= nv_nf2_thaw,
+	.hardreset              = nv_nf2_hardreset,
 };
 
+/* CK804 finally gets hardreset right */
 static struct ata_port_operations nv_ck804_ops = {
-	.inherits		= &nv_generic_ops,
+	.inherits		= &nv_common_ops,
 	.freeze			= nv_ck804_freeze,
 	.thaw			= nv_ck804_thaw,
 	.host_stop		= nv_ck804_host_stop,
 };
 
 static struct ata_port_operations nv_adma_ops = {
-	.inherits		= &nv_generic_ops,
+	.inherits		= &nv_ck804_ops,
 
 	.check_atapi_dma	= nv_adma_check_atapi_dma,
 	.sff_tf_read		= nv_adma_tf_read,
@@ -1544,6 +1562,17 @@ static void nv_nf2_thaw(struct ata_port *ap)
 	iowrite8(mask, scr_addr + NV_INT_ENABLE);
 }
 
+static int nv_nf2_hardreset(struct ata_link *link, unsigned int *class,
+			    unsigned long deadline)
+{
+	bool online;
+	int rc;
+
+	rc = sata_link_hardreset(link, sata_deb_timing_hotplug, deadline,
+				 &online, NULL);
+	return online ? -EAGAIN : rc;
+}
+
 static void nv_ck804_freeze(struct ata_port *ap)
 {
 	void __iomem *mmio_base = ap->host->iomap[NV_MMIO_BAR];
@@ -1596,21 +1625,6 @@ static void nv_mcp55_thaw(struct ata_port *ap)
 	ata_sff_thaw(ap);
 }
 
-static int nv_hardreset(struct ata_link *link, unsigned int *class,
-			unsigned long deadline)
-{
-	int rc;
-
-	/* SATA hardreset fails to retrieve proper device signature on
-	 * some controllers.  Request follow up SRST.  For more info,
-	 * see http://bugzilla.kernel.org/show_bug.cgi?id=3352
-	 */
-	rc = sata_sff_hardreset(link, class, deadline);
-	if (rc)
-		return rc;
-	return -EAGAIN;
-}
-
 static void nv_adma_error_handler(struct ata_port *ap)
 {
 	struct nv_adma_port_priv *pp = ap->private_data;