6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jinhui Guo guojinhui.liam@bytedance.com
[ Upstream commit d3429178ee51dd7155445d15a5ab87a45fae3c73 ]
When probing the I2C master, disable SMBus interrupts to prevent storms caused by broken firmware mis-configuring IC_SMBUS=1; the handler never services them and a mis-configured SMBUS Master extend-clock timeout or SMBUS Slave extend-clock timeout can flood the CPU.
Signed-off-by: Jinhui Guo guojinhui.liam@bytedance.com Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Acked-by: Mika Westerberg mika.westerberg@linux.intel.com Signed-off-by: Andi Shyti andi.shyti@kernel.org Link: https://lore.kernel.org/r/20251021075714.3712-2-guojinhui.liam@bytedance.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/i2c/busses/i2c-designware-core.h | 1 + drivers/i2c/busses/i2c-designware-master.c | 7 +++++++ 2 files changed, 8 insertions(+)
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h index e93870a0f9a4..f8feae20a7b2 100644 --- a/drivers/i2c/busses/i2c-designware-core.h +++ b/drivers/i2c/busses/i2c-designware-core.h @@ -79,6 +79,7 @@ #define DW_IC_TX_ABRT_SOURCE 0x80 #define DW_IC_ENABLE_STATUS 0x9c #define DW_IC_CLR_RESTART_DET 0xa8 +#define DW_IC_SMBUS_INTR_MASK 0xcc #define DW_IC_COMP_PARAM_1 0xf4 #define DW_IC_COMP_VERSION 0xf8 #define DW_IC_SDA_HOLD_MIN_VERS 0x3131312A /* "111*" == v1.11* */ diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c index e865869ccc50..56f124f32cac 100644 --- a/drivers/i2c/busses/i2c-designware-master.c +++ b/drivers/i2c/busses/i2c-designware-master.c @@ -184,6 +184,13 @@ static int i2c_dw_init_master(struct dw_i2c_dev *dev) /* Disable the adapter */ __i2c_dw_disable(dev);
+ /* + * Mask SMBus interrupts to block storms from broken + * firmware that leaves IC_SMBUS=1; the handler never + * services them. + */ + regmap_write(dev->map, DW_IC_SMBUS_INTR_MASK, 0); + /* Write standard speed timing parameters */ regmap_write(dev->map, DW_IC_SS_SCL_HCNT, dev->ss_hcnt); regmap_write(dev->map, DW_IC_SS_SCL_LCNT, dev->ss_lcnt);