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fsl/sata: create a sysfs entry for rx water mark

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Support config RX WATER MARK via sysfs when running at run-time;
A wrokaround for fix the exception happened to some WD HDD, found on
WD3000HLFS-01G6U1, WD3000HLFS-01G6U0, some SSD disks. The read performance
is also regression (about 30%) when use default value.

According to the latest documents, 0x10 is the default value of RX WATER MARK,
but exception/performance issue happened to some disks mentioned above.

The exception log as below when testing read performance with IOZone:
ata1.00: exception Emask 0x0 SAct 0x7 SErr 0x800000 action 0x6 frozen
ata1: SError: { LinkSeq }
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/00:00:ff:2c:14/01:00:02:00:00/40 tag 0 ncq 131072 in
res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
ata1.00: status: { DRDY }
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/00:08:ff:2d:14/01:00:02:00:00/40 tag 1 ncq 131072 in
res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
ata1.00: status: { DRDY }
ata1.00: failed command: WRITE FPDMA QUEUED
ata1.00: cmd 61/10:10:af:08:6e/00:00:12:00:00/40 tag 2 ncq 8192 out
res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
ata1.00: status: { DRDY }
ata1: hard resetting link
ata1: Hardreset failed, not off-lined 0
ata1: Signature Update detected @ 504 msecs
ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
ata1.00: configured for UDMA/133
ata1.00: device reported invalid CHS sector 0
ata1.00: device reported invalid CHS sector 0
ata1.00: device reported invalid CHS sector 0
ata1: EH complete

The exception/performance can be resolved when RX WATER MARK value is 0x16.

Signed-off-by: Qiang Liu <qiang.liu@freescale.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Qiang Liu 2013-03-04 15:20:23 +08:00 committed by Jeff Garzik
parent 7381fe7374
commit 7551c40d90
1 changed files with 55 additions and 0 deletions
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55
drivers/ata/sata_fsl.c
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@ -285,6 +285,7 @@ struct sata_fsl_host_priv {
int irq;
int data_snoop;
struct device_attribute intr_coalescing;
struct device_attribute rx_watermark;
};
static void fsl_sata_set_irq_coalescing(struct ata_host *host,
@ -343,6 +344,48 @@ static ssize_t fsl_sata_intr_coalescing_store(struct device *dev,
return strlen(buf);
}
static ssize_t fsl_sata_rx_watermark_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
unsigned int rx_watermark;
unsigned long flags;
struct ata_host *host = dev_get_drvdata(dev);
struct sata_fsl_host_priv *host_priv = host->private_data;
void __iomem *csr_base = host_priv->csr_base;
spin_lock_irqsave(&host->lock, flags);
rx_watermark = ioread32(csr_base + TRANSCFG);
rx_watermark &= 0x1f;
spin_unlock_irqrestore(&host->lock, flags);
return sprintf(buf, "%d\n", rx_watermark);
}
static ssize_t fsl_sata_rx_watermark_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
unsigned int rx_watermark;
unsigned long flags;
struct ata_host *host = dev_get_drvdata(dev);
struct sata_fsl_host_priv *host_priv = host->private_data;
void __iomem *csr_base = host_priv->csr_base;
u32 temp;
if (sscanf(buf, "%d", &rx_watermark) != 1) {
printk(KERN_ERR "fsl-sata: wrong parameter format.\n");
return -EINVAL;
}
spin_lock_irqsave(&host->lock, flags);
temp = ioread32(csr_base + TRANSCFG);
temp &= 0xffffffe0;
iowrite32(temp | rx_watermark, csr_base + TRANSCFG);
spin_unlock_irqrestore(&host->lock, flags);
return strlen(buf);
}
static inline unsigned int sata_fsl_tag(unsigned int tag,
void __iomem *hcr_base)
{
@ -1500,6 +1543,17 @@ static int sata_fsl_probe(struct platform_device *ofdev)
if (retval)
goto error_exit_with_cleanup;
host_priv->rx_watermark.show = fsl_sata_rx_watermark_show;
host_priv->rx_watermark.store = fsl_sata_rx_watermark_store;
sysfs_attr_init(&host_priv->rx_watermark.attr);
host_priv->rx_watermark.attr.name = "rx_watermark";
host_priv->rx_watermark.attr.mode = S_IRUGO | S_IWUSR;
retval = device_create_file(host->dev, &host_priv->rx_watermark);
if (retval) {
device_remove_file(&ofdev->dev, &host_priv->intr_coalescing);
goto error_exit_with_cleanup;
}
return 0;
error_exit_with_cleanup:
@ -1522,6 +1576,7 @@ static int sata_fsl_remove(struct platform_device *ofdev)
struct sata_fsl_host_priv *host_priv = host->private_data;
device_remove_file(&ofdev->dev, &host_priv->intr_coalescing);
device_remove_file(&ofdev->dev, &host_priv->rx_watermark);
ata_host_detach(host);