From 5a358b978618fbda598ccd30aae2243f5f08b206 Mon Sep 17 00:00:00 2001 From: Jensen Huang Date: Thu, 7 Dec 2023 16:21:59 +0800 Subject: [PATCH] i2c: rk3x: fix potential spinlock recursion on poll [ Upstream commit 19cde9c92b8d3b7ee555d0da3bcb0232d3a784f4 ] 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_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: Jensen Huang Reviewed-by: Heiko Stuebner Reviewed-by: Andi Shyti Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-rk3x.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c index a044ca0..4362db7 100644 --- a/drivers/i2c/busses/i2c-rk3x.c +++ b/drivers/i2c/busses/i2c-rk3x.c @@ -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); - rk3x_i2c_start(i2c); - if (!polling) { + rk3x_i2c_start(i2c); + 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) { -- 2.7.4