Commit 19cde9c9 authored by Jensen Huang's avatar Jensen Huang Committed by Wolfram Sang
Browse files

i2c: rk3x: fix potential spinlock recursion on poll 



Possible deadlock scenario (on reboot):
rk3x_i2c_xfer_common(polling)
    -> rk3x_i2c_wait_xfer_poll()
        -> rk3x_i2c_irq(0, i2c);
            --> spin_lock(&i2c->lock);
            ...
        <rk3x i2c interrupt>
        -> rk3x_i2c_irq(0, i2c);
            --> spin_lock(&i2c->lock); (deadlock here)

Store the IRQ number and disable/enable it around the polling transfer.
This patch has been tested on NanoPC-T4.

Signed-off-by: default avatarJensen Huang <jensenhuang@friendlyarm.com>
Reviewed-by: default avatarHeiko Stuebner <heiko@sntech.de>
Reviewed-by: default avatarAndi Shyti <andi.shyti@kernel.org>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent 043465b6

drivers/i2c/busses/i2c-rk3x.c

+11 −2
Original line number Diff line number Diff line
@@ -178,6 +178,7 @@ struct rk3x_i2c_soc_data { 
 * @clk: function clk for rk3399 or function & Bus clks for others

 * @pclk: Bus clk for rk3399

 * @clk_rate_nb: i2c clk rate change notify

 * @irq: irq number

 * @t: I2C known timing information

 * @lock: spinlock for the i2c bus

 * @wait: the waitqueue to wait for i2c transfer
@@ -200,6 +201,7 @@ struct rk3x_i2c { 
	struct clk *clk;

	struct clk *pclk;

	struct notifier_block clk_rate_nb;

	int irq;



	/* Settings */

	struct i2c_timings t;
@@ -1087,13 +1089,18 @@ static int rk3x_i2c_xfer_common(struct i2c_adapter *adap, 


		spin_unlock_irqrestore(&i2c->lock, flags);



		if (!polling) {

			rk3x_i2c_start(i2c);



		if (!polling) {

			timeout = wait_event_timeout(i2c->wait, !i2c->busy,

						     msecs_to_jiffies(WAIT_TIMEOUT));

		} else {

			disable_irq(i2c->irq);

			rk3x_i2c_start(i2c);



			timeout = rk3x_i2c_wait_xfer_poll(i2c);



			enable_irq(i2c->irq);

		}



		spin_lock_irqsave(&i2c->lock, flags);
@@ -1310,6 +1317,8 @@ static int rk3x_i2c_probe(struct platform_device *pdev) 
		return ret;

	}



	i2c->irq = irq;



	platform_set_drvdata(pdev, i2c);



	if (i2c->soc_data->calc_timings == rk3x_i2c_v0_calc_timings) {