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Commit effe0500 authored by Piotr Wojtaszczyk's avatar Piotr Wojtaszczyk Committed by Greg Kroah-Hartman
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i2c: pnx: Fix potential deadlock warning from del_timer_sync() call in isr 



[ Upstream commit f63b94be6942ba82c55343e196bd09b53227618e ]

When del_timer_sync() is called in an interrupt context it throws a warning
because of potential deadlock. The timer is used only to exit from
wait_for_completion() after a timeout so replacing the call with
wait_for_completion_timeout() allows to remove the problematic timer and
its related functions altogether.

Fixes: 41561f28 ("i2c: New Philips PNX bus driver")
Signed-off-by: default avatarPiotr Wojtaszczyk <piotr.wojtaszczyk@timesys.com>
Signed-off-by: default avatarAndi Shyti <andi.shyti@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 40945660

drivers/i2c/busses/i2c-pnx.c

+10 −38
Original line number Original line Diff line number Diff line
@@ -15,7 +15,6 @@ 
#include <linux/ioport.h>

#include <linux/ioport.h>

#include <linux/delay.h>

#include <linux/delay.h>

#include <linux/i2c.h>

#include <linux/i2c.h>

#include <linux/timer.h>

#include <linux/completion.h>

#include <linux/completion.h>

#include <linux/platform_device.h>

#include <linux/platform_device.h>

#include <linux/io.h>

#include <linux/io.h>
@@ -32,7 +31,6 @@ struct i2c_pnx_mif { 
	int			ret;		/* Return value */

	int			ret;		/* Return value */

	int			mode;		/* Interface mode */

	int			mode;		/* Interface mode */

	struct completion	complete;	/* I/O completion */

	struct completion	complete;	/* I/O completion */

	struct timer_list	timer;		/* Timeout */

	u8 *			buf;		/* Data buffer */

	u8 *			buf;		/* Data buffer */

	int			len;		/* Length of data buffer */

	int			len;		/* Length of data buffer */

	int			order;		/* RX Bytes to order via TX */

	int			order;		/* RX Bytes to order via TX */
@@ -117,24 +115,6 @@ static inline int wait_reset(struct i2c_pnx_algo_data *data) 
	return (timeout <= 0);

	return (timeout <= 0);

}

}





static inline void i2c_pnx_arm_timer(struct i2c_pnx_algo_data *alg_data)

{

	struct timer_list *timer = &alg_data->mif.timer;

	unsigned long expires = msecs_to_jiffies(alg_data->timeout);



	if (expires <= 1)

		expires = 2;



	del_timer_sync(timer);



	dev_dbg(&alg_data->adapter.dev, "Timer armed at %lu plus %lu jiffies.\n",

		jiffies, expires);



	timer->expires = jiffies + expires;



	add_timer(timer);

}



/**

/**

 * i2c_pnx_start - start a device

 * i2c_pnx_start - start a device

 * @slave_addr:		slave address

 * @slave_addr:		slave address
@@ -259,8 +239,6 @@ static int i2c_pnx_master_xmit(struct i2c_pnx_algo_data *alg_data) 
				~(mcntrl_afie | mcntrl_naie | mcntrl_drmie),

				~(mcntrl_afie | mcntrl_naie | mcntrl_drmie),

				  I2C_REG_CTL(alg_data));

				  I2C_REG_CTL(alg_data));





			del_timer_sync(&alg_data->mif.timer);



			dev_dbg(&alg_data->adapter.dev,

			dev_dbg(&alg_data->adapter.dev,

				"%s(): Waking up xfer routine.\n",

				"%s(): Waking up xfer routine.\n",

				__func__);

				__func__);
@@ -276,8 +254,6 @@ static int i2c_pnx_master_xmit(struct i2c_pnx_algo_data *alg_data) 
			~(mcntrl_afie | mcntrl_naie | mcntrl_drmie),

			~(mcntrl_afie | mcntrl_naie | mcntrl_drmie),

			  I2C_REG_CTL(alg_data));

			  I2C_REG_CTL(alg_data));





		/* Stop timer. */

		del_timer_sync(&alg_data->mif.timer);

		dev_dbg(&alg_data->adapter.dev,

		dev_dbg(&alg_data->adapter.dev,

			"%s(): Waking up xfer routine after zero-xfer.\n",

			"%s(): Waking up xfer routine after zero-xfer.\n",

			__func__);

			__func__);
@@ -364,8 +340,6 @@ static int i2c_pnx_master_rcv(struct i2c_pnx_algo_data *alg_data) 
				 mcntrl_drmie | mcntrl_daie);

				 mcntrl_drmie | mcntrl_daie);

			iowrite32(ctl, I2C_REG_CTL(alg_data));

			iowrite32(ctl, I2C_REG_CTL(alg_data));





			/* Kill timer. */

			del_timer_sync(&alg_data->mif.timer);

			complete(&alg_data->mif.complete);

			complete(&alg_data->mif.complete);

		}

		}

	}

	}
@@ -400,8 +374,6 @@ static irqreturn_t i2c_pnx_interrupt(int irq, void *dev_id) 
			 mcntrl_drmie);

			 mcntrl_drmie);

		iowrite32(ctl, I2C_REG_CTL(alg_data));

		iowrite32(ctl, I2C_REG_CTL(alg_data));





		/* Stop timer, to prevent timeout. */

		del_timer_sync(&alg_data->mif.timer);

		complete(&alg_data->mif.complete);

		complete(&alg_data->mif.complete);

	} else if (stat & mstatus_nai) {

	} else if (stat & mstatus_nai) {

		/* Slave did not acknowledge, generate a STOP */

		/* Slave did not acknowledge, generate a STOP */
@@ -419,8 +391,6 @@ static irqreturn_t i2c_pnx_interrupt(int irq, void *dev_id) 
		/* Our return value. */

		/* Our return value. */

		alg_data->mif.ret = -EIO;

		alg_data->mif.ret = -EIO;





		/* Stop timer, to prevent timeout. */

		del_timer_sync(&alg_data->mif.timer);

		complete(&alg_data->mif.complete);

		complete(&alg_data->mif.complete);

	} else {

	} else {

		/*

		/*
@@ -453,9 +423,8 @@ static irqreturn_t i2c_pnx_interrupt(int irq, void *dev_id) 
	return IRQ_HANDLED;

	return IRQ_HANDLED;

}

}





static void i2c_pnx_timeout(struct timer_list *t)

static void i2c_pnx_timeout(struct i2c_pnx_algo_data *alg_data)

{

{

	struct i2c_pnx_algo_data *alg_data = from_timer(alg_data, t, mif.timer);

	u32 ctl;

	u32 ctl;





	dev_err(&alg_data->adapter.dev,

	dev_err(&alg_data->adapter.dev,
@@ -472,7 +441,6 @@ static void i2c_pnx_timeout(struct timer_list *t) 
	iowrite32(ctl, I2C_REG_CTL(alg_data));

	iowrite32(ctl, I2C_REG_CTL(alg_data));

	wait_reset(alg_data);

	wait_reset(alg_data);

	alg_data->mif.ret = -EIO;

	alg_data->mif.ret = -EIO;

	complete(&alg_data->mif.complete);

}

}





static inline void bus_reset_if_active(struct i2c_pnx_algo_data *alg_data)

static inline void bus_reset_if_active(struct i2c_pnx_algo_data *alg_data)
@@ -514,6 +482,7 @@ i2c_pnx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 
	struct i2c_msg *pmsg;

	struct i2c_msg *pmsg;

	int rc = 0, completed = 0, i;

	int rc = 0, completed = 0, i;

	struct i2c_pnx_algo_data *alg_data = adap->algo_data;

	struct i2c_pnx_algo_data *alg_data = adap->algo_data;

	unsigned long time_left;

	u32 stat;

	u32 stat;





	dev_dbg(&alg_data->adapter.dev,

	dev_dbg(&alg_data->adapter.dev,
@@ -548,7 +517,6 @@ i2c_pnx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 
		dev_dbg(&alg_data->adapter.dev, "%s(): mode %d, %d bytes\n",

		dev_dbg(&alg_data->adapter.dev, "%s(): mode %d, %d bytes\n",

			__func__, alg_data->mif.mode, alg_data->mif.len);

			__func__, alg_data->mif.mode, alg_data->mif.len);





		i2c_pnx_arm_timer(alg_data);





		/* initialize the completion var */

		/* initialize the completion var */

		init_completion(&alg_data->mif.complete);

		init_completion(&alg_data->mif.complete);
@@ -564,7 +532,10 @@ i2c_pnx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 
			break;

			break;





		/* Wait for completion */

		/* Wait for completion */

		wait_for_completion(&alg_data->mif.complete);

		time_left = wait_for_completion_timeout(&alg_data->mif.complete,

							alg_data->timeout);

		if (time_left == 0)

			i2c_pnx_timeout(alg_data);





		if (!(rc = alg_data->mif.ret))

		if (!(rc = alg_data->mif.ret))

			completed++;

			completed++;
@@ -657,7 +628,10 @@ static int i2c_pnx_probe(struct platform_device *pdev) 
	alg_data->adapter.algo_data = alg_data;

	alg_data->adapter.algo_data = alg_data;

	alg_data->adapter.nr = pdev->id;

	alg_data->adapter.nr = pdev->id;





	alg_data->timeout = I2C_PNX_TIMEOUT_DEFAULT;

	alg_data->timeout = msecs_to_jiffies(I2C_PNX_TIMEOUT_DEFAULT);

	if (alg_data->timeout <= 1)

		alg_data->timeout = 2;



#ifdef CONFIG_OF

#ifdef CONFIG_OF

	alg_data->adapter.dev.of_node = of_node_get(pdev->dev.of_node);

	alg_data->adapter.dev.of_node = of_node_get(pdev->dev.of_node);

	if (pdev->dev.of_node) {

	if (pdev->dev.of_node) {
@@ -677,8 +651,6 @@ static int i2c_pnx_probe(struct platform_device *pdev) 
	if (IS_ERR(alg_data->clk))

	if (IS_ERR(alg_data->clk))

		return PTR_ERR(alg_data->clk);

		return PTR_ERR(alg_data->clk);





	timer_setup(&alg_data->mif.timer, i2c_pnx_timeout, 0);



	snprintf(alg_data->adapter.name, sizeof(alg_data->adapter.name),

	snprintf(alg_data->adapter.name, sizeof(alg_data->adapter.name),

		 "%s", pdev->name);

		 "%s", pdev->name);