From d944b27df121e2ee854a6c2fad13d6c6300792d4 Mon Sep 17 00:00:00 2001 From: Kai-Heng Feng Date: Tue, 24 Mar 2020 23:28:11 +0800 Subject: [PATCH] i2c: nvidia-gpu: Handle timeout correctly in gpu_i2c_check_status() Nvidia card may come with a "phantom" UCSI device, and its driver gets stuck in probe routine, prevents any system PM operations like suspend. There's an unaccounted case that the target time can equal to jiffies in gpu_i2c_check_status(), let's solve that by using readl_poll_timeout() instead of jiffies comparison functions. Fixes: c71bcdcb42a7 ("i2c: add i2c bus driver for NVIDIA GPU") Suggested-by: Andy Shevchenko Signed-off-by: Kai-Heng Feng Reviewed-by: Andy Shevchenko Reviewed-by: Ajay Gupta Tested-by: Ajay Gupta Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-nvidia-gpu.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/drivers/i2c/busses/i2c-nvidia-gpu.c b/drivers/i2c/busses/i2c-nvidia-gpu.c index 62e18b4..f5d25ce 100644 --- a/drivers/i2c/busses/i2c-nvidia-gpu.c +++ b/drivers/i2c/busses/i2c-nvidia-gpu.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -75,20 +76,15 @@ static void gpu_enable_i2c_bus(struct gpu_i2c_dev *i2cd) static int gpu_i2c_check_status(struct gpu_i2c_dev *i2cd) { - unsigned long target = jiffies + msecs_to_jiffies(1000); u32 val; + int ret; - do { - val = readl(i2cd->regs + I2C_MST_CNTL); - if (!(val & I2C_MST_CNTL_CYCLE_TRIGGER)) - break; - if ((val & I2C_MST_CNTL_STATUS) != - I2C_MST_CNTL_STATUS_BUS_BUSY) - break; - usleep_range(500, 600); - } while (time_is_after_jiffies(target)); - - if (time_is_before_jiffies(target)) { + ret = readl_poll_timeout(i2cd->regs + I2C_MST_CNTL, val, + !(val & I2C_MST_CNTL_CYCLE_TRIGGER) || + (val & I2C_MST_CNTL_STATUS) != I2C_MST_CNTL_STATUS_BUS_BUSY, + 500, 1000 * USEC_PER_MSEC); + + if (ret) { dev_err(i2cd->dev, "i2c timeout error %x\n", val); return -ETIMEDOUT; } -- 2.7.4