aboutsummaryrefslogtreecommitdiffstats
path: root/drivers
diff options
context:
space:
mode:
authorTejun Heo <htejun@gmail.com>2006-07-26 02:59:26 -0400
committerJeff Garzik <jeff@garzik.org>2006-07-29 04:01:31 -0400
commit9f5920567bfabbd1be26112a31c44652b6587394 (patch)
tree27e06539d48f05b85693ba2e9854ebf9a5a4abd7 /drivers
parentd8fcd116d203dfe2f6c272d0cd67724b172f1bc2 (diff)
[PATCH] ahci: simplify ahci_start_engine()
Simplify ahci_start_engine() by killing prerequisite condition checks. Rationales are.. * No user checks error return from ahci_start_engine() * Code flow guarantees the prerequisite conditions unless the controller is malfunctioning. In such cases, the driver had chances to learn about the problem _before_ calling this function. * Closely related to the above two, driver calls into this function even when prerequisites fail hoping for the best. Basically, ahci_start_engine() should only do the operation itself. It isn't the right place to check for prerequisites. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Zhao, Forrest <forrest.zhao@intel.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/scsi/ahci.c21
1 files changed, 2 insertions, 19 deletions
diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index ee00aed9bdea..e02b9c65287b 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -406,32 +406,15 @@ static void ahci_scr_write (struct ata_port *ap, unsigned int sc_reg_in,
406 writel(val, (void __iomem *) ap->ioaddr.scr_addr + (sc_reg * 4)); 406 writel(val, (void __iomem *) ap->ioaddr.scr_addr + (sc_reg * 4));
407} 407}
408 408
409static int ahci_start_engine(void __iomem *port_mmio) 409static void ahci_start_engine(void __iomem *port_mmio)
410{ 410{
411 u32 tmp; 411 u32 tmp;
412 412
413 /* get current status */
414 tmp = readl(port_mmio + PORT_CMD);
415
416 /* AHCI rev 1.1 section 10.3.1:
417 * Software shall not set PxCMD.ST to '1' until it verifies
418 * that PxCMD.CR is '0' and has set PxCMD.FRE to '1'
419 */
420 if ((tmp & PORT_CMD_FIS_RX) == 0)
421 return -EPERM;
422
423 /* wait for engine to become idle */
424 tmp = ata_wait_register(port_mmio + PORT_CMD,
425 PORT_CMD_LIST_ON, PORT_CMD_LIST_ON, 1,500);
426 if (tmp & PORT_CMD_LIST_ON)
427 return -EBUSY;
428
429 /* start DMA */ 413 /* start DMA */
414 tmp = readl(port_mmio + PORT_CMD);
430 tmp |= PORT_CMD_START; 415 tmp |= PORT_CMD_START;
431 writel(tmp, port_mmio + PORT_CMD); 416 writel(tmp, port_mmio + PORT_CMD);
432 readl(port_mmio + PORT_CMD); /* flush */ 417 readl(port_mmio + PORT_CMD); /* flush */
433
434 return 0;
435} 418}
436 419
437static int ahci_stop_engine(void __iomem *port_mmio) 420static int ahci_stop_engine(void __iomem *port_mmio)