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sata_fsl: add support for interrupt coalsecing feature 

Adds support for interrupt coalescing feature to reduce interrupt events.
Provides a mechanism of adjusting coalescing count and timeout tick by sysfs
at runtime, so that tradeoff of latency and CPU load can be made depending
on different applications.

Signed-off-by: Qiang Liu <qiang.liu@freescale.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Qiang Liu 2012-02-15 15:40:34 +08:00 committed by Jeff Garzik
parent 40679b3ce9
commit 6b4b8fc87d
1 changed files with 107 additions and 4 deletions
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111
drivers/ata/sata_fsl.c
View File

@ -6,7 +6,7 @@
* Author: Ashish Kalra <ashish.kalra@freescale.com>
* Li Yang <leoli@freescale.com>
*
* Copyright (c) 2006-2007, 2011 Freescale Semiconductor, Inc.
* Copyright (c) 2006-2007, 2011-2012 Freescale Semiconductor, Inc.
*
* 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
@ -26,6 +26,15 @@
#include <asm/io.h>
#include <linux/of_platform.h>
static unsigned int intr_coalescing_count;
module_param(intr_coalescing_count, int, S_IRUGO);
MODULE_PARM_DESC(intr_coalescing_count,
"INT coalescing count threshold (1..31)");
static unsigned int intr_coalescing_ticks;
module_param(intr_coalescing_ticks, int, S_IRUGO);
MODULE_PARM_DESC(intr_coalescing_ticks,
"INT coalescing timer threshold in AHB ticks");
/* Controller information */
enum {
SATA_FSL_QUEUE_DEPTH = 16,
@ -82,6 +91,16 @@ enum {
SATA_FSL_IRQ_FLAG = IRQF_SHARED,
};
/*
* Interrupt Coalescing Control Register bitdefs */
enum {
ICC_MIN_INT_COUNT_THRESHOLD = 1,
ICC_MAX_INT_COUNT_THRESHOLD = ((1 << 5) - 1),
ICC_MIN_INT_TICKS_THRESHOLD = 0,
ICC_MAX_INT_TICKS_THRESHOLD = ((1 << 19) - 1),
ICC_SAFE_INT_TICKS = 1,
};
/*
* Host Controller command register set - per port
*/
@ -263,8 +282,65 @@ struct sata_fsl_host_priv {
void __iomem *csr_base;
int irq;
int data_snoop;
struct device_attribute intr_coalescing;
};
static void fsl_sata_set_irq_coalescing(struct ata_host *host,
unsigned int count, unsigned int ticks)
{
struct sata_fsl_host_priv *host_priv = host->private_data;
void __iomem *hcr_base = host_priv->hcr_base;
if (count > ICC_MAX_INT_COUNT_THRESHOLD)
count = ICC_MAX_INT_COUNT_THRESHOLD;
else if (count < ICC_MIN_INT_COUNT_THRESHOLD)
count = ICC_MIN_INT_COUNT_THRESHOLD;
if (ticks > ICC_MAX_INT_TICKS_THRESHOLD)
ticks = ICC_MAX_INT_TICKS_THRESHOLD;
else if ((ICC_MIN_INT_TICKS_THRESHOLD == ticks) &&
(count > ICC_MIN_INT_COUNT_THRESHOLD))
ticks = ICC_SAFE_INT_TICKS;
spin_lock(&host->lock);
iowrite32((count << 24 | ticks), hcr_base + ICC);
intr_coalescing_count = count;
intr_coalescing_ticks = ticks;
spin_unlock(&host->lock);
DPRINTK("intrrupt coalescing, count = 0x%x, ticks = %x\n",
intr_coalescing_count, intr_coalescing_ticks);
DPRINTK("ICC register status: (hcr base: 0x%x) = 0x%x\n",
hcr_base, ioread32(hcr_base + ICC));
}
static ssize_t fsl_sata_intr_coalescing_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%d %d\n",
intr_coalescing_count, intr_coalescing_ticks);
}
static ssize_t fsl_sata_intr_coalescing_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
unsigned int coalescing_count, coalescing_ticks;
if (sscanf(buf, "%d%d",
&coalescing_count,
&coalescing_ticks) != 2) {
printk(KERN_ERR "fsl-sata: wrong parameter format.\n");
return -EINVAL;
}
fsl_sata_set_irq_coalescing(dev_get_drvdata(dev),
coalescing_count, coalescing_ticks);
return strlen(buf);
}
static inline unsigned int sata_fsl_tag(unsigned int tag,
void __iomem *hcr_base)
{
@ -346,10 +422,10 @@ static unsigned int sata_fsl_fill_sg(struct ata_queued_cmd *qc, void *cmd_desc,
(unsigned long long)sg_addr, sg_len);
/* warn if each s/g element is not dword aligned */
if (sg_addr & 0x03)
if (unlikely(sg_addr & 0x03))
ata_port_err(qc->ap, "s/g addr unaligned : 0x%llx\n",
(unsigned long long)sg_addr);
if (sg_len & 0x03)
if (unlikely(sg_len & 0x03))
ata_port_err(qc->ap, "s/g len unaligned : 0x%x\n",
sg_len);
@ -1245,6 +1321,13 @@ static int sata_fsl_init_controller(struct ata_host *host)
iowrite32(0x00000FFFF, hcr_base + CE);
iowrite32(0x00000FFFF, hcr_base + DE);
/*
* reset the number of command complete bits which will cause the
* interrupt to be signaled
*/
fsl_sata_set_irq_coalescing(host, intr_coalescing_count,
intr_coalescing_ticks);
/*
* host controller will be brought on-line, during xx_port_start()
* callback, that should also initiate the OOB, COMINIT sequence
@ -1309,7 +1392,7 @@ static int sata_fsl_probe(struct platform_device *ofdev)
void __iomem *csr_base = NULL;
struct sata_fsl_host_priv *host_priv = NULL;
int irq;
struct ata_host *host;
struct ata_host *host = NULL;
u32 temp;
struct ata_port_info pi = sata_fsl_port_info[0];
@ -1356,6 +1439,10 @@ static int sata_fsl_probe(struct platform_device *ofdev)
/* allocate host structure */
host = ata_host_alloc_pinfo(&ofdev->dev, ppi, SATA_FSL_MAX_PORTS);
if (!host) {
retval = -ENOMEM;
goto error_exit_with_cleanup;
}
/* host->iomap is not used currently */
host->private_data = host_priv;
@ -1373,10 +1460,24 @@ static int sata_fsl_probe(struct platform_device *ofdev)
dev_set_drvdata(&ofdev->dev, host);
host_priv->intr_coalescing.show = fsl_sata_intr_coalescing_show;
host_priv->intr_coalescing.store = fsl_sata_intr_coalescing_store;
sysfs_attr_init(&host_priv->intr_coalescing.attr);
host_priv->intr_coalescing.attr.name = "intr_coalescing";
host_priv->intr_coalescing.attr.mode = S_IRUGO | S_IWUSR;
retval = device_create_file(host->dev, &host_priv->intr_coalescing);
if (retval)
goto error_exit_with_cleanup;
return 0;
error_exit_with_cleanup:
if (host) {
dev_set_drvdata(&ofdev->dev, NULL);
ata_host_detach(host);
}
if (hcr_base)
iounmap(hcr_base);
if (host_priv)
@ -1390,6 +1491,8 @@ static int sata_fsl_remove(struct platform_device *ofdev)
struct ata_host *host = dev_get_drvdata(&ofdev->dev);
struct sata_fsl_host_priv *host_priv = host->private_data;
device_remove_file(&ofdev->dev, &host_priv->intr_coalescing);
ata_host_detach(host);
dev_set_drvdata(&ofdev->dev, NULL);