[PATCH 2/6] ipr: Remove unnecessary interrupt clearing on new adapters

[Brian King <brking@xxxxxxxxxxxxxxxxxx>]

The latest ipr hardware no longer requires the driver to issue any MMIOs
to clear the interrupt so remove this to optimize performance.

Signed-off-by: Brian King <brking@xxxxxxxxxxxxxxxxxx>
---

 drivers/scsi/ipr.c |   21 +++++++++++++++------
 drivers/scsi/ipr.h |    2 ++
 2 files changed, 17 insertions(+), 6 deletions(-)

diff -puN drivers/scsi/ipr.h~ipr_skip_interrupt_clear drivers/scsi/ipr.h
--- linux-2.6/drivers/scsi/ipr.h~ipr_skip_interrupt_clear	2012-03-10 07:31:38.000000000 -0600
+++ linux-2.6-bjking1/drivers/scsi/ipr.h	2012-03-10 07:31:38.000000000 -0600
@@ -1306,6 +1306,7 @@ struct ipr_interrupts {
 struct ipr_chip_cfg_t {
 	u32 mailbox;
 	u8 cache_line_size;
+	u8 clear_isr;
 	struct ipr_interrupt_offsets regs;
 };
 
@@ -1388,6 +1389,7 @@ struct ipr_ioa_cfg {
 	u8 sis64:1;
 	u8 dump_timeout:1;
 	u8 cfg_locked:1;
+	u8 clear_isr:1;
 
 	u8 revid;
 
diff -puN drivers/scsi/ipr.c~ipr_skip_interrupt_clear drivers/scsi/ipr.c
--- linux-2.6/drivers/scsi/ipr.c~ipr_skip_interrupt_clear	2012-03-10 07:31:38.000000000 -0600
+++ linux-2.6-bjking1/drivers/scsi/ipr.c	2012-03-10 07:31:38.000000000 -0600
@@ -105,6 +105,7 @@ static const struct ipr_chip_cfg_t ipr_c
 	{ /* Gemstone, Citrine, Obsidian, and Obsidian-E */
 		.mailbox = 0x0042C,
 		.cache_line_size = 0x20,
+		.clear_isr = 1,
 		{
 			.set_interrupt_mask_reg = 0x0022C,
 			.clr_interrupt_mask_reg = 0x00230,
@@ -127,6 +128,7 @@ static const struct ipr_chip_cfg_t ipr_c
 	{ /* Snipe and Scamp */
 		.mailbox = 0x0052C,
 		.cache_line_size = 0x20,
+		.clear_isr = 1,
 		{
 			.set_interrupt_mask_reg = 0x00288,
 			.clr_interrupt_mask_reg = 0x0028C,
@@ -149,6 +151,7 @@ static const struct ipr_chip_cfg_t ipr_c
 	{ /* CRoC */
 		.mailbox = 0x00044,
 		.cache_line_size = 0x20,
+		.clear_isr = 0,
 		{
 			.set_interrupt_mask_reg = 0x00010,
 			.clr_interrupt_mask_reg = 0x00018,
@@ -5049,12 +5052,14 @@ static irqreturn_t ipr_handle_other_inte
 		del_timer(&ioa_cfg->reset_cmd->timer);
 		ipr_reset_ioa_job(ioa_cfg->reset_cmd);
 	} else if ((int_reg & IPR_PCII_HRRQ_UPDATED) == int_reg) {
-		if (ipr_debug && printk_ratelimit())
-			dev_err(&ioa_cfg->pdev->dev,
-				"Spurious interrupt detected. 0x%08X\n", int_reg);
-		writel(IPR_PCII_HRRQ_UPDATED, ioa_cfg->regs.clr_interrupt_reg32);
-		int_reg = readl(ioa_cfg->regs.sense_interrupt_reg32);
-		return IRQ_NONE;
+		if (ioa_cfg->clear_isr) {
+			if (ipr_debug && printk_ratelimit())
+				dev_err(&ioa_cfg->pdev->dev,
+					"Spurious interrupt detected. 0x%08X\n", int_reg);
+			writel(IPR_PCII_HRRQ_UPDATED, ioa_cfg->regs.clr_interrupt_reg32);
+			int_reg = readl(ioa_cfg->regs.sense_interrupt_reg32);
+			return IRQ_NONE;
+		}
 	} else {
 		if (int_reg & IPR_PCII_IOA_UNIT_CHECKED)
 			ioa_cfg->ioa_unit_checked = 1;
@@ -5154,6 +5159,9 @@ static irqreturn_t ipr_isr(int irq, void
 			}
 		}
 
+		if (ipr_cmd && !ioa_cfg->clear_isr)
+			break;
+
 		if (ipr_cmd != NULL) {
 			/* Clear the PCI interrupt */
 			num_hrrq = 0;
@@ -8769,6 +8777,7 @@ static int __devinit ipr_probe_ioa(struc
 	/* set SIS 32 or SIS 64 */
 	ioa_cfg->sis64 = ioa_cfg->ipr_chip->sis_type == IPR_SIS64 ? 1 : 0;
 	ioa_cfg->chip_cfg = ioa_cfg->ipr_chip->cfg;
+	ioa_cfg->clear_isr = ioa_cfg->chip_cfg->clear_isr;
 
 	if (ipr_transop_timeout)
 		ioa_cfg->transop_timeout = ipr_transop_timeout;
_

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