From: Denis Turischev <denis@compulab.co.il>
To: jgarzik@pobox.com
Cc: linux-ide@vger.kernel.org, stable@kernel.org
Subject: pata_sch: fix PSTS register reading.
Date: Wed, 20 Jan 2010 13:45:22 +0200 [thread overview]
Message-ID: <4B56ECD2.20107@compulab.co.il> (raw)
pata_sch: fix PSTS register reading.
According to Poulsbo SCH datasheet (p. 353): "Reading reserved bits returns
an indeterminate, inconsistent value".
Bit 7 of PSTS register read as 1 when there is slave disk drive attached,
despite being described as reserved with zero value. This causes wrong
feature
decoding in ata_sff_tf_read.
Fix it by implementing pata_sch specific sff_tf_read with appropriate bit
masks on PSTS register.
Signed-off-by: Denis Turischev <denis@compulab.co.il>
CC: stable@kernel.org
--- linux-2.6.33-rc4.orig/drivers/ata/pata_sch.c 2010-01-13
07:15:00.000000000 +0200
+++ linux-2.6.33-rc4/drivers/ata/pata_sch.c 2010-01-20
11:19:16.000000000 +0200
@@ -49,6 +49,11 @@
USD = (1 << 31), /* Use Synchronous DMA */
};
+/* see SCH datasheet page 353 */
+enum {
+ PSTSM = 0x7f, /* PSTS Bit Mask */
+};
+
static int sch_init_one(struct pci_dev *pdev,
const struct pci_device_id *ent);
static void sch_set_piomode(struct ata_port *ap, struct ata_device *adev);
@@ -75,11 +80,47 @@
ATA_BMDMA_SHT(DRV_NAME),
};
+/**
+ * sch_tf_read - input device's ATA taskfile shadow registers
+ * @ap: Port from which input is read
+ * @tf: ATA taskfile register set for storing input
+ *
+ * Note: Original code is ata_sff_tf_read().
+ */
+
+static void sch_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
+{
+ struct ata_ioports *ioaddr = &ap->ioaddr;
+
+ tf->command = ata_sff_check_status(ap);
+ tf->feature = ioread8(ioaddr->error_addr) && PSTSM;
+ tf->nsect = ioread8(ioaddr->nsect_addr);
+ tf->lbal = ioread8(ioaddr->lbal_addr);
+ tf->lbam = ioread8(ioaddr->lbam_addr);
+ tf->lbah = ioread8(ioaddr->lbah_addr);
+ tf->device = ioread8(ioaddr->device_addr);
+
+ if (tf->flags & ATA_TFLAG_LBA48) {
+ if (likely(ioaddr->ctl_addr)) {
+ iowrite8(tf->ctl | ATA_HOB, ioaddr->ctl_addr);
+ tf->hob_feature = ioread8(ioaddr->error_addr) && PSTSM;
+ tf->hob_nsect = ioread8(ioaddr->nsect_addr);
+ tf->hob_lbal = ioread8(ioaddr->lbal_addr);
+ tf->hob_lbam = ioread8(ioaddr->lbam_addr);
+ tf->hob_lbah = ioread8(ioaddr->lbah_addr);
+ iowrite8(tf->ctl, ioaddr->ctl_addr);
+ ap->last_ctl = tf->ctl;
+ } else
+ WARN_ON_ONCE(1);
+ }
+}
+
static struct ata_port_operations sch_pata_ops = {
.inherits = &ata_bmdma_port_ops,
.cable_detect = ata_cable_unknown,
.set_piomode = sch_set_piomode,
.set_dmamode = sch_set_dmamode,
+ .sff_tf_read = sch_tf_read,
};
static struct ata_port_info sch_port_info = {
next reply other threads:[~2010-01-20 11:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-20 11:45 Denis Turischev [this message]
2010-01-20 13:37 ` pata_sch: fix PSTS register reading Alan Cox
2010-01-20 13:41 ` Sergei Shtylyov
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