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| author |   Hans de Goede <hdegoede@redhat.com> | 2018-10-11 16:29:10 +0200 |
|---|---|---|
| committer |   Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2018-10-25 17:00:05 +0200 |
| commit | 3c670dba864d9ab0a23612a93b7d98700734bd44 (patch) | |
| tree | 1718fbc1c3f426f3da42d27abd5abfd7738bd7ac /drivers/acpi | |
| parent | x86: baytrail/cherrytrail: Rework and move P-Unit PMIC bus semaphore code (diff) | |
| download | linux-dev-3c670dba864d9ab0a23612a93b7d98700734bd44.tar.xz linux-dev-3c670dba864d9ab0a23612a93b7d98700734bd44.zip | |
ACPI / PMIC: xpower: Block P-Unit I2C access during read-modify-write
intel_xpower_pmic_update_power() does a read-modify-write of the output
control register. The i2c-designware code blocks the P-Unit I2C access
during the read and write by taking the P-Unit's PMIC bus semaphore.
But between the read and the write that semaphore is released and the
P-Unit could make changes to the register which we then end up overwriting.
This commit makes intel_xpower_pmic_update_power() take the semaphore
itself so that it is held over the entire read-modify-write, avoiding this
race.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi')
| -rw-r--r-- | drivers/acpi/pmic/intel_pmic_xpower.c | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/acpi/pmic/intel_pmic_xpower.c b/drivers/acpi/pmic/intel_pmic_xpower.c index aadc86db804c..2579675b7082 100644 --- a/drivers/acpi/pmic/intel_pmic_xpower.c +++ b/drivers/acpi/pmic/intel_pmic_xpower.c @@ -8,8 +8,9 @@ #include <linux/acpi.h> #include <linux/init.h> #include <linux/mfd/axp20x.h> -#include <linux/platform_device.h> #include <linux/regmap.h> +#include <linux/platform_device.h> +#include <asm/iosf_mbi.h> #include "intel_pmic.h" #define XPOWER_GPADC_LOW 0x5b @@ -172,15 +173,21 @@ static int intel_xpower_pmic_get_power(struct regmap *regmap, int reg, static int intel_xpower_pmic_update_power(struct regmap *regmap, int reg, int bit, bool on) { - int data; + int data, ret; /* GPIO1 LDO regulator needs special handling */ if (reg == XPOWER_GPI1_CTRL) return regmap_update_bits(regmap, reg, GPI1_LDO_MASK, on ? GPI1_LDO_ON : GPI1_LDO_OFF); - if (regmap_read(regmap, reg, &data)) - return -EIO; + ret = iosf_mbi_block_punit_i2c_access(); + if (ret) + return ret; + + if (regmap_read(regmap, reg, &data)) { + ret = -EIO; + goto out; + } if (on) data |= BIT(bit); @@ -188,9 +195,11 @@ static int intel_xpower_pmic_update_power(struct regmap *regmap, int reg, data &= ~BIT(bit); if (regmap_write(regmap, reg, data)) - return -EIO; + ret = -EIO; +out: + iosf_mbi_unblock_punit_i2c_access(); - return 0; + return ret; } /** |