ahci: don't enable port irq before handler is registered

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
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

2 files changed, 16 insertions, 3 deletions

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 633159b5152a..d38c40fe4ddb 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1919,7 +1919,17 @@ 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)
@@ -1935,7 +1945,10 @@ 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 423c0a6952b2..5096b2a24a17 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;