Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 6b4b8fc8 authored by Qiang Liu's avatar Qiang Liu Committed by Jeff Garzik
Browse files

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: default avatarQiang Liu <qiang.liu@freescale.com>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent 40679b3c

drivers/ata/sata_fsl.c

+107 −4
Original line number Diff line number Diff line
@@ -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);