Enable reliable use of Message-Signaled Interrupts (MSI) in sata_mv
by masking further chip interrupts within the main interrupt handler.
Based upon a suggestion by Grant Grundler.
MSI is working reliably in all of my test systems here now.
Signed-off-by: Mark Lord <mlord@xxxxxxxxx>
---
This replaces the originally posted [PATCH 05/04] version.
--- old/drivers/ata/sata_mv.c 2009-01-21 10:16:59.000000000 -0500
+++ linux/drivers/ata/sata_mv.c 2009-01-21 10:22:28.000000000 -0500
@@ -33,8 +33,6 @@
*
* --> ATAPI support (Marvell claims the 60xx/70xx chips can do it).
*
- * --> Investigate problems with PCI Message Signalled Interrupts (MSI).
- *
* --> Develop a low-power-consumption strategy, and implement it.
*
* --> [Experiment, low priority] Investigate interrupt coalescing.
@@ -70,7 +68,7 @@
#include <linux/libata.h>
#define DRV_NAME "sata_mv"
-#define DRV_VERSION "1.24"
+#define DRV_VERSION "1.25"
enum {
/* BAR's are enumerated in terms of pci_resource_start() terms */
@@ -2199,9 +2197,15 @@
struct ata_host *host = dev_instance;
struct mv_host_priv *hpriv = host->private_data;
unsigned int handled = 0;
+ int using_msi = hpriv->hp_flags & MV_HP_FLAG_MSI;
u32 main_irq_cause, pending_irqs;
spin_lock(&host->lock);
+
+ /* for MSI: block new interrupts while in here */
+ if (using_msi)
+ writel(0, hpriv->main_irq_mask_addr);
+
main_irq_cause = readl(hpriv->main_irq_cause_addr);
pending_irqs = main_irq_cause & hpriv->main_irq_mask;
/*
@@ -2215,6 +2219,11 @@
handled = mv_host_intr(host, pending_irqs);
}
spin_unlock(&host->lock);
+
+ /* for MSI: unmask; interrupt cause bits will retrigger now */
+ if (using_msi)
+ writel(hpriv->main_irq_mask, hpriv->main_irq_mask_addr);
+
return IRQ_RETVAL(handled);
}
@@ -3414,9 +3423,9 @@
if (rc)
return rc;
- /* Enable interrupts */
- if (msi && pci_enable_msi(pdev))
- pci_intx(pdev, 1);
+ /* Enable message-switched interrupts, if requested */
+ if (msi && 0 == pci_enable_msi(pdev))
+ hpriv->hp_flags |= MV_HP_FLAG_MSI;
mv_dump_pci_cfg(pdev, 0x68);
mv_print_info(host);
--
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