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authorZhang Rui <rui.zhang@intel.com>2008-07-04 13:32:17 +0800
committerJeff Garzik <jgarzik@redhat.com>2008-07-14 15:59:33 -0400
commit24920c8a6358bf5532f1336b990b1c0fe2b599ee (patch)
tree576c2dcbde9c76e13585ed37208640fbd3dba005 /drivers/ata
parent1e9dbc9291738149577cc488fd441f061815e02e (diff)
downloadlinux-24920c8a6358bf5532f1336b990b1c0fe2b599ee.tar.gz
AHCI: speed up resume
During resume, sleep 1 second to wait for the HBA reset
to finish is a waste of time.

According to the AHCI 1.2 spec,
We should poll the HOST_CTL register,
and return error if the host reset is not
finished within 1 second.

Test results show that the HBA reset can be done quickly(in usecs).
And this patch may save nearly 1 second during resume.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Diffstat (limited to 'drivers/ata')
-rw-r--r--drivers/ata/ahci.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 65d4e968feb4..4ff3f03cf97b 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1142,12 +1142,15 @@ static int ahci_reset_controller(struct ata_host *host)
 			readl(mmio + HOST_CTL); /* flush */
 		}
 
-		/* reset must complete within 1 second, or
+		/*
+		 * to perform host reset, OS should set HOST_RESET
+		 * and poll until this bit is read to be "0".
+		 * reset must complete within 1 second, or
 		 * the hardware should be considered fried.
 		 */
-		ssleep(1);
+		tmp = ata_wait_register(mmio + HOST_CTL, HOST_RESET,
+					HOST_RESET, 10, 1000);
 
-		tmp = readl(mmio + HOST_CTL);
 		if (tmp & HOST_RESET) {
 			dev_printk(KERN_ERR, host->dev,
 				   "controller reset failed (0x%x)\n", tmp);