Commit e683c6cf authored by leoliu-oc's avatar leoliu-oc
Browse files

i2c: zhaoxin: update support for Zhaoxin I2C controller 

zhaoxin inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I9CQGS


CVE: NA

-----------------

During each byte access, the host performs clock stretching.
In this case, the thread may be interrupted by preemption,
resulting in a long stretching time.
However, some touchpad can only tolerate host clock stretching
of no more than 200 ms. We reduce the impact of this through
a retransmission mechanism.

Signed-off-by: default avatarleoliu-oc <leoliu-oc@zhaoxin.com>
parent 70460587

drivers/i2c/busses/i2c-zhaoxin.c

+41 −19
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-or-later

/*

 *  Copyright(c) 2021 Shanghai Zhaoxin Semiconductor Corporation.

 *  Copyright(c) 2023 Shanghai Zhaoxin Semiconductor Corporation.

 *                    All rights reserved.

 */



#define DRIVER_VERSION "1.5.2"



#include <linux/acpi.h>

#include <linux/delay.h>

#include <linux/err.h>

#include <linux/i2c.h>

#include <linux/interrupt.h>

#include <linux/io.h>

#include <linux/ktime.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/version.h>



#define DRIVER_VERSION "1.5.1"



#define ZX_I2C_NAME "i2c_zhaoxin"



/* REG_CR Bit fields */
@@ -86,6 +87,8 @@ struct zxi2c { 
	u16 csr;

	u8 fstp;

	u8 hrv;

	ktime_t ti;

	ktime_t to;

};



/* parameters Constants */
@@ -93,10 +96,11 @@ struct zxi2c { 
#define ZXI2C_GOLD_FSTP_400K	0x38

#define ZXI2C_GOLD_FSTP_1M		0x13

#define ZXI2C_GOLD_FSTP_3400K	0x37



#define ZXI2C_HS_MASTER_CODE	(0x08 << 8)

#define ZXI2C_FIFO_SIZE		32



#define ZXI2C_TIMEOUT		200



static int zxi2c_wait_bus_ready(struct zxi2c *i2c)

{

	unsigned long timeout;
@@ -122,9 +126,29 @@ static int zxi2c_wait_status(struct zxi2c *i2c, u8 status) 
{

	unsigned long time_left;



	time_left = wait_for_completion_timeout(&i2c->complete, msecs_to_jiffies(500));

	if (time_left <= 1)

		return -ETIMEDOUT;

	time_left = wait_for_completion_timeout(&i2c->complete, msecs_to_jiffies(ZXI2C_TIMEOUT));

	if (!time_left) {

		dev_err(i2c->dev, "bus transfer timeout\n");

		return -EIO;

	}



	/*

	 * During each byte access, the host performs clock stretching.

	 * In this case, the thread may be interrupted by preemption,

	 * resulting in a long stretching time.

	 * However, some touchpad can only tolerate host clock stretching

	 * of no more than 200 ms. We reduce the impact of this through

	 * a retransmission mechanism.

	 */

	local_irq_disable();

	i2c->to = ktime_get();

	if (ktime_to_ms(ktime_sub(i2c->to, i2c->ti)) > ZXI2C_TIMEOUT) {

		local_irq_enable();

		dev_warn(i2c->dev, "thread has been blocked for a while\n");

		return -EAGAIN;

	}

	i2c->ti = i2c->to;

	local_irq_enable();



	if (i2c->cmd_status & status)

		return 0;
@@ -279,9 +303,9 @@ static int zxi2c_fifo_xfer(struct zxi2c *i2c, struct i2c_msg *msg) 
		iowrite8(tmp | ZXI2C_HCR_RST_FIFO, base + ZXI2C_REG_HCR);



		/* set xfer len */

		if (read) {

		if (read)

			iowrite8(xfer_len - 1, base + ZXI2C_REG_HRLR);

		} else {

		else {

			iowrite8(xfer_len - 1, base + ZXI2C_REG_HTLR);

			/* set write data */

			for (i = 0; i < xfer_len; i++)
@@ -335,6 +359,7 @@ static int zxi2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int 
	tmp = ioread8(i2c->base + ZXI2C_REG_CR);

	tmp &= ~(ZXI2C_CR_RX_END | ZXI2C_CR_TX_END);



	i2c->ti = ktime_get();

	if (num == 1 && msgs->len >= 2 && (i2c->hrv || msgs->len <= ZXI2C_FIFO_SIZE)) {

		/* enable fifo mode */

		iowrite16(ZXI2C_CR_FIFO_MODE | tmp, i2c->base + ZXI2C_REG_CR);
@@ -359,10 +384,6 @@ static int zxi2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int 
	/* dis interrupt */

	iowrite8(0, i2c->base + ZXI2C_REG_IMR);



	/* timeout may caused by another high-priority process, try again */

	if (ret == -ETIMEDOUT)

		ret = -EAGAIN;



	return ret;

}
@@ -461,8 +482,10 @@ static int zxi2c_init(struct platform_device *pdev, struct zxi2c **pi2c) 
		return i2c->irq;



	err = devm_request_irq(&pdev->dev, i2c->irq, zxi2c_isr, IRQF_SHARED, pdev->name, i2c);

	if (err)

		return dev_err_probe(&pdev->dev, err, "failed to request irq %i\n", i2c->irq);

	if (err) {

		dev_err(&pdev->dev, "failed to request irq %i\n", i2c->irq);

		return err;

	}



	i2c->dev = &pdev->dev;

	init_completion(&i2c->complete);
@@ -491,7 +514,6 @@ static int zxi2c_probe(struct platform_device *pdev) 
	adap->algo = &zxi2c_algorithm;

	adap->retries = 2;

	adap->quirks = &zxi2c_quirks;



	adap->dev.parent = &pdev->dev;

	ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev->dev));

	snprintf(adap->name, sizeof(adap->name), "zhaoxin-%s-%s", dev_name(pdev->dev.parent),
@@ -548,7 +570,7 @@ static struct platform_driver zxi2c_driver = { 
	.remove = zxi2c_remove,

	.driver = {

		.name = ZX_I2C_NAME,

		.acpi_match_table = ACPI_PTR(zxi2c_acpi_match),

		.acpi_match_table = zxi2c_acpi_match,

		.pm = &zxi2c_pm,

	},

};