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authorMarek BehĂșn <kabel@kernel.org>2021-04-08 04:00:00 +0200
committerWolfram Sang <wsa@kernel.org>2021-04-15 22:13:19 +0200
commit39930213e7779b9c4257499972b8afb8858f1a2d (patch)
tree39feba35d1d635c23526d99c5bc634110d77ee54
parentd434405aaab7d0ebc516b68a8fc4100922d7f5ef (diff)
i2c: mv64xxx: Fix random system lock caused by runtime PM
I noticed a weird bug with this driver on Marvell CN9130 Customer Reference Board. Sometime after boot, the system locks with the following message: [104.071363] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 The system does not respond afterwards, only warns about RCU stalls. This first appeared with commit e5c02cf54154 ("i2c: mv64xxx: Add runtime PM support"). With further experimentation I discovered that adding a delay into mv64xxx_i2c_hw_init() fixes this issue. This function is called before every xfer, due to how runtime PM works in this driver. It seems that in order to work correctly, a delay is needed after the bus is reset in this function. Since there already is a known erratum with this controller needing a delay, I assume that this is just another place this needs to be applied. Therefore I apply the delay only if errata_delay is true. Signed-off-by: Marek BehĂșn <kabel@kernel.org> Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com> Reviewed-by: Samuel Holland <samuel@sholland.org> Signed-off-by: Wolfram Sang <wsa@kernel.org>
-rw-r--r--drivers/i2c/busses/i2c-mv64xxx.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index c590d36b5fd1..5c8e94b6cdb5 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -221,6 +221,10 @@ mv64xxx_i2c_hw_init(struct mv64xxx_i2c_data *drv_data)
writel(0, drv_data->reg_base + drv_data->reg_offsets.ext_addr);
writel(MV64XXX_I2C_REG_CONTROL_TWSIEN | MV64XXX_I2C_REG_CONTROL_STOP,
drv_data->reg_base + drv_data->reg_offsets.control);
+
+ if (drv_data->errata_delay)
+ udelay(5);
+
drv_data->state = MV64XXX_I2C_STATE_IDLE;
}