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i2c: designware: Disable SMBus interrupts to prevent storms from mis-configured firmware

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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
This commit is contained in:
Jinhui Guo 2025-10-21 15:57:14 +08:00 committed by Andi Shyti
parent 3f124b4ef8
commit d3429178ee
2 changed files with 8 additions and 0 deletions
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1
drivers/i2c/busses/i2c-designware-core.h
View File

@ -78,6 +78,7 @@
#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* */

7
drivers/i2c/busses/i2c-designware-master.c
View File

@ -220,6 +220,13 @@ 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);