libata-pmp-prep: implement sata_async_notification()

AN serves multiple purposes.  For ATAPI, it's used for media change
notification.  For PMP, for downstream PHY status change notification.
Implement sata_async_notification() which demultiplexes AN.

To avoid unnecessary port events, ATAPI AN is not enabled if PMP is
attached but SNTF is not available.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Kriten Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 7 insertions, 17 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index cf3404467ceb..9f3c591c7214 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1356,27 +1356,17 @@ static void ahci_port_intr(struct ata_port *ap)
         }
 
         if (status & PORT_IRQ_SDB_FIS) {
-                /*
-                 * if this is an ATAPI device with AN turned on,
-                 * then we should interrogate the device to
-                 * determine the cause of the interrupt
-                 *
-                 * for AN - this we should check the SDB FIS
-                 * and find the I and N bits set
+                /* If the 'N' bit in word 0 of the FIS is set, we just
+                 * received asynchronous notification.  Tell libata
+                 * about it.  Note that as the SDB FIS itself is
+                 * accessible, SNotification can be emulated by the
+                 * driver but don't bother for the time being.
                  */
                 const __le32 *f = pp->rx_fis + RX_FIS_SDB;
                 u32 f0 = le32_to_cpu(f[0]);
 
-                /* check the 'N' bit in word 0 of the FIS */
-                if (f0 & (1 << 15)) {
-                        int port_addr = ((f0 & 0x00000f00) >> 8);
-                        struct ata_device *adev;
-                        if (port_addr < ATA_MAX_DEVICES) {
-                                adev = &ap->link.device[port_addr];
-                                if (adev->flags & ATA_DFLAG_AN)
-                                        ata_scsi_media_change_notify(adev);
-                        }
-                }
+                if (f0 & (1 << 15))
+                        sata_async_notification(ap);
         }
 
         if (ap->link.sactive)