Re: [PATCH #upstream-fixes] sata_promise: request follow-up SRST

[Mikael Pettersson <mikpe@it.uu.se>]

Jeff Garzik writes:
 > hrm....   at this point we have deviated massively from the standard 
 > Promise method of hard reset...
 > 
 > * set PMP port
 > * make hotplug irqs
 > * reset port# in PDC_GLOBAL_CTL
 > * pdc_reset_port()
 > * reset FPDMA -- probably a good idea even if not doing FPDMA
 > * clear SATA Error register (0xffffffff)
 > * clear errors-reported-from-link-layer register
 > * wait standard length of time for SATA connection
 > * clear hotplug bits
 > * set PMP port
 > 
 > The PDC_GLOBAL_CTL bitbang is the most notable missing element in the 

I assume you meant the PCI control register (offset 0x48).

 > hard reset path, though we also miss clearing an apparently-important 
 > error register as well.  FPDMA reset would be a good idea I think, even 
 > if not in use, mainly for paranoia's sake and because that's what 
 > Promise's driver does.

Here's a patch on top of 2.6.28-rc6 that should make sata_promise's
reset sequences a closer match to what Promise's drivers do.

- soft reset (pdc_reset_port):
  * wait for ATA engine to not be in packet command mode (2nd gen only)
  * write reset bit in PDC_CTLSTAT before the first read in the loop
  * for 2nd gen SATA follow up with FPDMA reset and clearing error status registers
- hard reset (pdc_sata_hardreset):
  * wait for ATA engine to not be in packet command mode (2nd gen only)
  * reset ATA engine via the PCI control register
  * Tejun's change to use non-waiting hardreset + follow-up SRST

I'm not changing the hotplug mask bits since they are taken care
of by sata_promise's ->freeze() and ->thaw() operations. And I'm
not writing the PMP port # because that's always zero (for now).

Tested here on a SATAII150 TX2plus w/ two sata disks, some hdparm -y
+ smartctl tests which used to cause timeouts on one of those disks,
and some parallel dd:s to stress things a little. No issues found.
I'll test it on a 1st gen 20378 next week.

Testers welcome.

/Mikael

--- linux-2.6.28-rc6/drivers/ata/sata_promise.c.~1~	2008-11-29 16:05:04.000000000 +0100
+++ linux-2.6.28-rc6/drivers/ata/sata_promise.c	2008-11-29 20:26:26.000000000 +0100
@@ -56,6 +56,7 @@ enum {
 	/* host register offsets (from host->iomap[PDC_MMIO_BAR]) */
 	PDC_INT_SEQMASK		= 0x40,	/* Mask of asserted SEQ INTs */
 	PDC_FLASH_CTL		= 0x44, /* Flash control register */
+	PDC_PCI_CTL		= 0x48, /* PCI control/status reg */
 	PDC_SATA_PLUG_CSR	= 0x6C, /* SATA Plug control/status reg */
 	PDC2_SATA_PLUG_CSR	= 0x60, /* SATAII Plug control/status reg */
 	PDC_TBG_MODE		= 0x41C, /* TBG mode (not SATAII) */
@@ -75,7 +76,17 @@ enum {
 	PDC_CTLSTAT		= 0x60,	/* IDE control and status (per port) */
 
 	/* per-port SATA register offsets (from ap->ioaddr.scr_addr) */
+	PDC_SATA_ERROR		= 0x04,
 	PDC_PHYMODE4		= 0x14,
+	PDC_LINK_LAYER_ERRORS	= 0x6C,
+	PDC_FPDMA_CTLSTAT	= 0xD8,
+	PDC_INTERNAL_DEBUG_1	= 0xF8,	/* also used for PATA */
+	PDC_INTERNAL_DEBUG_2	= 0xFC,	/* also used for PATA */
+
+	/* PDC_FPDMA_CTLSTAT bit definitions */
+	PDC_FPDMA_CTLSTAT_RESET			= 1 << 3,
+	PDC_FPDMA_CTLSTAT_DMASETUP_INT_FLAG	= 1 << 10,
+	PDC_FPDMA_CTLSTAT_SETDB_INT_FLAG	= 1 << 11,
 
 	/* PDC_GLOBAL_CTL bit definitions */
 	PDC_PH_ERR		= (1 <<  8), /* PCI error while loading packet */
@@ -354,12 +365,76 @@ static int pdc_sata_port_start(struct at
 	return 0;
 }
 
+static void pdc_fpdma_clear_interrupt_flag(struct ata_port *ap)
+{
+	void __iomem *sata_mmio = ap->ioaddr.scr_addr;
+	u32 tmp;
+
+	tmp = readl(sata_mmio + PDC_FPDMA_CTLSTAT);
+	tmp |= PDC_FPDMA_CTLSTAT_DMASETUP_INT_FLAG;
+	tmp |= PDC_FPDMA_CTLSTAT_SETDB_INT_FLAG;
+
+	/* It's not allowed to write to the entire FPDMA_CTLSTAT register
+	   when NCQ is running. So do a byte-sized write to bits 10 and 11. */
+	writeb(tmp >> 8, sata_mmio + PDC_FPDMA_CTLSTAT + 1);
+	readb(sata_mmio + PDC_FPDMA_CTLSTAT + 1); /* flush */
+}
+
+static void pdc_fpdma_reset(struct ata_port *ap)
+{
+	void __iomem *sata_mmio = ap->ioaddr.scr_addr;
+	u8 tmp;
+
+	tmp = (u8)readl(sata_mmio + PDC_FPDMA_CTLSTAT);
+	tmp &= 0x7F;
+	tmp |= PDC_FPDMA_CTLSTAT_RESET;
+	writeb(tmp, sata_mmio + PDC_FPDMA_CTLSTAT);
+	readl(sata_mmio + PDC_FPDMA_CTLSTAT); /* flush */
+	udelay(100);
+	tmp &= ~PDC_FPDMA_CTLSTAT_RESET;
+	writeb(tmp, sata_mmio + PDC_FPDMA_CTLSTAT);
+	readl(sata_mmio + PDC_FPDMA_CTLSTAT); /* flush */
+
+	pdc_fpdma_clear_interrupt_flag(ap);
+}
+
+static void pdc_not_at_command_packet_phase(struct ata_port *ap)
+{
+	void __iomem *sata_mmio = ap->ioaddr.scr_addr;
+	unsigned int i;
+	u32 tmp;
+
+	/* check not at ASIC packet command phase */
+	for (i = 0; i < 100; ++i) {
+		writel(0, sata_mmio + PDC_INTERNAL_DEBUG_1);
+		tmp = readl(sata_mmio + PDC_INTERNAL_DEBUG_2);
+		if ((tmp & 0xF) != 1)
+			break;
+		udelay(100);
+	}
+}
+
+static void pdc_clear_internal_debug_record_error_register(struct ata_port *ap)
+{
+	void __iomem *sata_mmio = ap->ioaddr.scr_addr;
+
+	writel(0xffffffff, sata_mmio + PDC_SATA_ERROR);
+	writel(0xffff0000, sata_mmio + PDC_LINK_LAYER_ERRORS);
+}
+
 static void pdc_reset_port(struct ata_port *ap)
 {
 	void __iomem *ata_ctlstat_mmio = ap->ioaddr.cmd_addr + PDC_CTLSTAT;
 	unsigned int i;
 	u32 tmp;
 
+	if (ap->flags & PDC_FLAG_GEN_II)
+		pdc_not_at_command_packet_phase(ap);
+
+	tmp = readl(ata_ctlstat_mmio);
+	tmp |= PDC_RESET;
+	writel(tmp, ata_ctlstat_mmio);
+
 	for (i = 11; i > 0; i--) {
 		tmp = readl(ata_ctlstat_mmio);
 		if (tmp & PDC_RESET)
@@ -374,6 +449,11 @@ static void pdc_reset_port(struct ata_po
 	tmp &= ~PDC_RESET;
 	writel(tmp, ata_ctlstat_mmio);
 	readl(ata_ctlstat_mmio);	/* flush */
+
+	if (sata_scr_valid(&ap->link) && (ap->flags & PDC_FLAG_GEN_II)) {
+		pdc_fpdma_reset(ap);
+		pdc_clear_internal_debug_record_error_register(ap);
+	}
 }
 
 static int pdc_pata_cable_detect(struct ata_port *ap)
@@ -706,11 +786,50 @@ static int pdc_pata_softreset(struct ata
 	return ata_sff_softreset(link, class, deadline);
 }
 
+static unsigned int pdc_ata_port_to_ata_no(const struct ata_port *ap)
+{
+	void __iomem *ata_mmio = ap->ioaddr.cmd_addr;
+	void __iomem *host_mmio = ap->host->iomap[PDC_MMIO_BAR];
+
+	/* ata_mmio == host_mmio + 0x200 + ata_no * 0x80 */
+	return (ata_mmio - host_mmio - 0x200) / 0x80;
+}
+
+static void pdc_hard_reset_port(struct ata_port *ap)
+{
+	void __iomem *host_mmio = ap->host->iomap[PDC_MMIO_BAR];
+	void __iomem *pcictl_b1_mmio = host_mmio + PDC_PCI_CTL + 1;
+	unsigned int ata_no = pdc_ata_port_to_ata_no(ap);
+	u8 tmp;
+
+	spin_lock(&ap->host->lock);
+
+	tmp = readb(pcictl_b1_mmio);
+	tmp &= ~(0x10 << ata_no);
+	writeb(tmp, pcictl_b1_mmio);
+	readb(pcictl_b1_mmio); /* flush */
+	udelay(100);
+	tmp |= (0x10 << ata_no);
+	writeb(tmp, pcictl_b1_mmio);
+	readb(pcictl_b1_mmio); /* flush */
+
+	spin_unlock(&ap->host->lock);
+}
+
 static int pdc_sata_hardreset(struct ata_link *link, unsigned int *class,
 			      unsigned long deadline)
 {
+	if (link->ap->flags & PDC_FLAG_GEN_II)
+		pdc_not_at_command_packet_phase(link->ap);
+	/* hotplug IRQs should have been masked by pdc_sata_freeze() */
+	pdc_hard_reset_port(link->ap);
 	pdc_reset_port(link->ap);
-	return sata_sff_hardreset(link, class, deadline);
+
+	/* sata_promise can't reliably acquire the first D2H Reg FIS
+	 * after hardreset.  Do non-waiting hardreset and request
+	 * follow-up SRST.
+	 */
+	return sata_std_hardreset(link, class, deadline);
 }
 
 static void pdc_error_handler(struct ata_port *ap)