[PATCH v2] ahci: don't enable port irq before handler is registered

[Maxime Bizon <mbizon@freebox.fr>]

From: Maxime Bizon <mbizon@freebox.fr>

The ahci_pmp_attach() & ahci_pmp_detach() unmask port irqs, but they
are also called during port initialization, before ahci host irq
handler is registered. On ce4100 platform, this sometimes triggers
"irq 4: nobody cared" message when loading driver.

Fixed this by not touching the register if the port is in frozen
state, and mark all uninitialized port as frozen.

Signed-off-by: Maxime Bizon <mbizon@freebox.fr>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org

---
 drivers/ata/libahci.c     |   17 +++++++++++++++--
 drivers/ata/libata-core.c |    2 +-
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 26d4523..8498eb5 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1897,7 +1897,17 @@ static void ahci_pmp_attach(struct ata_port *ap)
 	ahci_enable_fbs(ap);
 
 	pp->intr_mask |= PORT_IRQ_BAD_PMP;
-	writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
+
+	/*
+	 * We must not change the port interrupt mask register if the
+	 * port is marked frozen, the value in pp->intr_mask will be
+	 * restored later when the port is thawed.
+	 *
+	 * Note that during initialization, the port is marked as
+	 * frozen since the irq handler is not yet registered.
+	 */
+	if (!(ap->pflags & ATA_PFLAG_FROZEN))
+		writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
 }
 
 static void ahci_pmp_detach(struct ata_port *ap)
@@ -1913,7 +1923,10 @@ static void ahci_pmp_detach(struct ata_port *ap)
 	writel(cmd, port_mmio + PORT_CMD);
 
 	pp->intr_mask &= ~PORT_IRQ_BAD_PMP;
-	writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
+
+	/* see comment above in ahci_pmp_attach() */
+	if (!(ap->pflags & ATA_PFLAG_FROZEN))
+		writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
 }
 
 int ahci_port_resume(struct ata_port *ap)
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index d4e52e2..02d5703 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5480,7 +5480,7 @@ struct ata_port *ata_port_alloc(struct ata_host *host)
 	if (!ap)
 		return NULL;
 	
-	ap->pflags |= ATA_PFLAG_INITIALIZING;
+	ap->pflags |= ATA_PFLAG_INITIALIZING | ATA_PFLAG_FROZEN;
 	ap->lock = &host->lock;
 	ap->print_id = -1;
 	ap->host = host;
-- 
1.7.1




-- 
Maxime