diff options
Diffstat (limited to 'drivers/scsi/sata_svw.c')
| -rw-r--r-- | drivers/scsi/sata_svw.c | 43 |
1 files changed, 24 insertions, 19 deletions
diff --git a/drivers/scsi/sata_svw.c b/drivers/scsi/sata_svw.c index 858e07185db..19d3bb3b0fb 100644 --- a/drivers/scsi/sata_svw.c +++ b/drivers/scsi/sata_svw.c @@ -13,21 +13,26 @@ * This driver probably works with non-Apple versions of the * Broadcom chipset... * - * The contents of this file are subject to the Open - * Software License version 1.1 that can be found at - * http://www.opensource.org/licenses/osl-1.1.txt and is included herein - * by reference. * - * Alternatively, the contents of this file may be used under the terms - * of the GNU General Public License version 2 (the "GPL") as distributed - * in the kernel source COPYING file, in which case the provisions of - * the GPL are applicable instead of the above. If you wish to allow - * the use of your version of this file only under the terms of the - * GPL and not to allow others to use your version of this file under - * the OSL, indicate your decision by deleting the provisions above and - * replace them with the notice and other provisions required by the GPL. - * If you do not delete the provisions above, a recipient may use your - * version of this file under either the OSL or the GPL. + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; see the file COPYING. If not, write to + * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. + * + * + * libata documentation is available via 'make {ps|pdf}docs', + * as Documentation/DocBook/libata.* + * + * Hardware documentation available under NDA. * */ @@ -195,18 +200,18 @@ static void k2_bmdma_start_mmio (struct ata_queued_cmd *qc) /* start host DMA transaction */ dmactl = readb(mmio + ATA_DMA_CMD); writeb(dmactl | ATA_DMA_START, mmio + ATA_DMA_CMD); - /* There is a race condition in certain SATA controllers that can - be seen when the r/w command is given to the controller before the + /* There is a race condition in certain SATA controllers that can + be seen when the r/w command is given to the controller before the host DMA is started. On a Read command, the controller would initiate the command to the drive even before it sees the DMA start. When there - are very fast drives connected to the controller, or when the data request + are very fast drives connected to the controller, or when the data request hits in the drive cache, there is the possibility that the drive returns a part or all of the requested data to the controller before the DMA start is issued. In this case, the controller would become confused as to what to do with the data. In the worst case when all the data is returned back to the controller, the controller could hang. In other cases it could return partial data returning in data corruption. This problem has been seen in PPC systems and can also appear - on an system with very fast disks, where the SATA controller is sitting behind a + on an system with very fast disks, where the SATA controller is sitting behind a number of bridges, and hence there is significant latency between the r/w command and the start command. */ /* issue r/w command if the access is to ATA*/ @@ -214,7 +219,7 @@ static void k2_bmdma_start_mmio (struct ata_queued_cmd *qc) ap->ops->exec_command(ap, &qc->tf); } - + static u8 k2_stat_check_status(struct ata_port *ap) { return readl((void *) ap->ioaddr.status_addr); |