From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Marek Behún" <kabel@kernel.org>,
"Gregory CLEMENT" <gregory.clement@bootlin.com>,
"Samuel Holland" <samuel@sholland.org>,
"Wolfram Sang" <wsa@kernel.org>,
"Sasha Levin" <sashal@kernel.org>,
linux-i2c@vger.kernel.org
Subject: [PATCH AUTOSEL 4.4 5/7] i2c: mv64xxx: Fix random system lock caused by runtime PM
Date: Mon, 19 Apr 2021 16:46:06 -0400 [thread overview]
Message-ID: <20210419204608.7191-5-sashal@kernel.org> (raw)
In-Reply-To: <20210419204608.7191-1-sashal@kernel.org>
From: Marek Behún <kabel@kernel.org>
[ Upstream commit 39930213e7779b9c4257499972b8afb8858f1a2d ]
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 Behún <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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/i2c/busses/i2c-mv64xxx.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 332d32c53c41..73324f047932 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -219,6 +219,10 @@ 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;
}
--
2.30.2
next prev parent reply other threads:[~2021-04-19 20:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-19 20:46 [PATCH AUTOSEL 4.4 1/7] ARM: dts: Fix swapped mmc order for omap3 Sasha Levin
2021-04-19 20:46 ` [PATCH AUTOSEL 4.4 2/7] s390/entry: save the caller of psw_idle Sasha Levin
2021-04-19 20:46 ` [PATCH AUTOSEL 4.4 3/7] xen-netback: Check for hotplug-status existence before watching Sasha Levin
2021-04-19 20:46 ` [PATCH AUTOSEL 4.4 4/7] cavium/liquidio: Fix duplicate argument Sasha Levin
2021-04-19 20:46 ` Sasha Levin [this message]
2021-04-19 20:46 ` [PATCH AUTOSEL 4.4 6/7] ia64: fix discontig.c section mismatches Sasha Levin
2021-04-19 20:46 ` [PATCH AUTOSEL 4.4 7/7] ia64: tools: remove duplicate definition of ia64_mf() on ia64 Sasha Levin
2021-04-26 21:11 ` [PATCH AUTOSEL 4.4 1/7] ARM: dts: Fix swapped mmc order for omap3 Pavel Machek
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