[PATCH 3/3] Add disk hotswap support to libata RESEND #5

[Lukasz Kosewski <lkosewsk@gmail.com>]

Hey Jeff, all,

Patch 3/3 for libata hotswapping, the reference implementation for the
API in Patch #2 for Promise SATA150 and SATAII150 Tx4 and Tx2 Plus
controllers.  Seems to be working on UP machines (heavy, heavy
testing) and SMP (2 processor Athlon machine, fairly heavy testing).

Lots of comments available in patch and header, please review and
apply if you like it!

This patch depends on patch 1 to apply, and patch 1 and 2 to compile and work.

Luke Kosewski

26.09.05    Luke Kosewski   <lkosewsk@nit.ca>

	* A patch to sata_promise.c (dependent on patches 1 and 2 in this
	  series) which makes it use the hotswap API in patch 2.  The Promise
	  controllers are fairly simple in terms of their hotplug mechanism,
	  so none of the funky 'janitor' functions are used here.
	  ata_hotplug_plug is called on a plug event, and ata_hotplug_unplug on
	  an unplug.  Simple, simple.
	* Pending some confirmation and suggestions from Jim Ramsay
	  (jim.ramsay@gmail.com) the interrupt handler might change to check for
	  DMA commands completing as WELL as hotplug events in the same pass.

diff -rpuN linux-2.6.14-rc1/drivers/scsi/sata_promise.c linux-2.6.14-rc1-new/drivers/scsi/sata_promise.c
--- linux-2.6.14-rc1/drivers/scsi/sata_promise.c	2005-09-14 19:57:54.000000000 -0400
+++ linux-2.6.14-rc1-new/drivers/scsi/sata_promise.c	2005-09-14 20:16:09.000000000 -0400
@@ -332,10 +332,43 @@ static void pdc_reset_port(struct ata_po
 	readl(mmio);	/* flush */
 }
 
+/* Mask hotplug interrupts for one channel (ap) */
+static inline void pdc_disable_channel_hotplug_interrupts(struct ata_port *ap)
+{
+	struct pdc_host_priv *hp = ap->host_set->private_data;
+	void *mmio = ap->host_set->mmio_base + hp->hotplug_offset + 2;
+
+	u8 maskflags = readb(mmio);
+	maskflags |= (0x11 << (u8)ap->hard_port_no);
+	writeb(maskflags, mmio);
+}
+
+/* Clear and unmask hotplug interrupts for one channel (ap) */
+static inline void pdc_enable_channel_hotplug_interrupts(struct ata_port *ap)
+{
+	struct pdc_host_priv *hp = ap->host_set->private_data;
+	void *mmio = ap->host_set->mmio_base + hp->hotplug_offset;
+
+	//Clear channel hotplug interrupts
+	u8 maskflags = readb(mmio);
+	maskflags |= (0x11 << (u8)ap->hard_port_no);
+	writeb(maskflags, mmio);
+
+	//Unmask channel hotplug interrupts
+	maskflags = readb(mmio + 2);
+	maskflags &= ~(0x11 << (u8)ap->hard_port_no);
+	writeb(maskflags, mmio + 2);
+}
+
 static void pdc_sata_phy_reset(struct ata_port *ap)
 {
 	pdc_reset_port(ap);
-	sata_phy_reset(ap);
+	if (ap->flags & ATA_FLAG_SATA_RESET) {
+		pdc_disable_channel_hotplug_interrupts(ap);
+		sata_phy_reset(ap);
+		pdc_enable_channel_hotplug_interrupts(ap);
+	} else
+		sata_phy_reset(ap);
 }
 
 static void pdc_pata_phy_reset(struct ata_port *ap)
@@ -485,11 +518,13 @@ static void pdc_irq_clear(struct ata_por
 static irqreturn_t pdc_interrupt (int irq, void *dev_instance, struct pt_regs *regs)
 {
 	struct ata_host_set *host_set = dev_instance;
+	struct pdc_host_priv *hp = host_set->private_data;
 	struct ata_port *ap;
 	u32 mask = 0;
 	unsigned int i, tmp;
-	unsigned int handled = 0;
+	unsigned int handled = 0, hotplug_offset = hp->hotplug_offset;
 	void __iomem *mmio_base;
+	u8 plugdata, maskflags;
 
 	VPRINTK("ENTER\n");
 
@@ -513,7 +548,7 @@ static irqreturn_t pdc_interrupt (int ir
 	mask &= 0xffff;		/* only 16 tags possible */
 	if (!mask) {
 		VPRINTK("QUICK EXIT 3\n");
-		goto done_irq;
+		goto try_hotplug;
 	}
 
 	writel(mask, mmio_base + PDC_INT_SEQMASK);
@@ -532,7 +567,36 @@ static irqreturn_t pdc_interrupt (int ir
 		}
 	}
 
-	VPRINTK("EXIT\n");
+	if (handled) {
+		VPRINTK("EXIT 4\n");
+		goto done_irq;
+	}
+
+try_hotplug:
+	plugdata = readb(mmio_base + hotplug_offset);
+	maskflags = readb(mmio_base + hotplug_offset + 2);
+	plugdata &= ~maskflags;
+	if (plugdata) {
+		writeb(plugdata, mmio_base + hotplug_offset);
+		for (i = 0; i < host_set->n_ports; ++i) {
+			ap = host_set->ports[i];
+			if (!(ap->flags & ATA_FLAG_SATA))
+				continue;  //No PATA support here... yet
+			// Check unplug flag
+			if (plugdata & 0x1) {
+				/* Do stuff related to unplugging a device */
+				ata_hotplug_unplug(ap);
+				handled = 1;
+			} else if ((plugdata >> 4) & 0x1) {  //Check plug flag
+				/* Do stuff related to plugging in a device */
+				ata_hotplug_plug(ap);
+				handled = 1;
+			}
+			plugdata >>= 1;
+		}
+	}
+
+	VPRINTK("EXIT 5\n");
 
 done_irq:
 	spin_unlock(&host_set->lock);
@@ -632,9 +696,9 @@ static void pdc_host_init(unsigned int c
 	tmp = readl(mmio + hotplug_offset);
 	writel(tmp | 0xff, mmio + hotplug_offset);
 
-	/* mask plug/unplug ints */
+	/* unmask plug/unplug ints */
 	tmp = readl(mmio + hotplug_offset);
-	writel(tmp | 0xff0000, mmio + hotplug_offset);
+	writel(tmp & ~0xff0000, mmio + hotplug_offset);
 
 	/* reduce TBG clock to 133 Mhz. */
 	tmp = readl(mmio + PDC_TBG_MODE);