The Qualcomm LPASS LPI pin controller driver uses one lock for guarding Read-Modify-Write code for slew rate registers. However the pin configuration and muxing registers have exactly the same RMW code but are not protected.

Pin controller framework does not provide locking here, thus it is possible to trigger simultaneous change of pin configuration registers resulting in non-atomic changes.

Protect from concurrent access by re-using the same lock used to cover the slew rate register. Using the same lock instead of adding second one will make more sense, once we add support for newer Qualcomm SoC, where slew rate is configured in the same register as pin configuration/muxing.

Fixes: 6e261d1090d6 ("pinctrl: qcom: Add sm8250 lpass lpi pinctrl driver") Cc: stable@vger.kernel.org Reviewed-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org

---

Added Linus' review. Resending because no one picked up this patch. --- drivers/pinctrl/qcom/pinctrl-lpass-lpi.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/pinctrl/qcom/pinctrl-lpass-lpi.c b/drivers/pinctrl/qcom/pinctrl-lpass-lpi.c index abb6f1de230b..9651aed048cf 100644 --- a/drivers/pinctrl/qcom/pinctrl-lpass-lpi.c +++ b/drivers/pinctrl/qcom/pinctrl-lpass-lpi.c @@ -32,7 +32,8 @@ struct lpi_pinctrl { char __iomem *tlmm_base; char __iomem *slew_base; struct clk_bulk_data clks[MAX_LPI_NUM_CLKS]; - struct mutex slew_access_lock; + /* Protects from concurrent register updates */ + struct mutex lock; DECLARE_BITMAP(ever_gpio, MAX_NR_GPIO); const struct lpi_pinctrl_variant_data *data; }; @@ -103,6 +104,7 @@ static int lpi_gpio_set_mux(struct pinctrl_dev *pctldev, unsigned int function, if (WARN_ON(i == g->nfuncs)) return -EINVAL;

+ mutex_lock(&pctrl->lock); val = lpi_gpio_read(pctrl, pin, LPI_GPIO_CFG_REG);

/* @@ -128,6 +130,7 @@ static int lpi_gpio_set_mux(struct pinctrl_dev *pctldev, unsigned int function,

u32p_replace_bits(&val, i, LPI_GPIO_FUNCTION_MASK); lpi_gpio_write(pctrl, pin, LPI_GPIO_CFG_REG, val); + mutex_unlock(&pctrl->lock);

return 0; } @@ -233,14 +236,14 @@ static int lpi_config_set(struct pinctrl_dev *pctldev, unsigned int group, if (slew_offset == LPI_NO_SLEW) break;

- mutex_lock(&pctrl->slew_access_lock); + mutex_lock(&pctrl->lock);

sval = ioread32(pctrl->slew_base + LPI_SLEW_RATE_CTL_REG); sval &= ~(LPI_SLEW_RATE_MASK << slew_offset); sval |= arg << slew_offset; iowrite32(sval, pctrl->slew_base + LPI_SLEW_RATE_CTL_REG);

- mutex_unlock(&pctrl->slew_access_lock); + mutex_unlock(&pctrl->lock); break; default: return -EINVAL; @@ -256,6 +259,7 @@ static int lpi_config_set(struct pinctrl_dev *pctldev, unsigned int group, lpi_gpio_write(pctrl, group, LPI_GPIO_VALUE_REG, val); }

+ mutex_lock(&pctrl->lock); val = lpi_gpio_read(pctrl, group, LPI_GPIO_CFG_REG);

u32p_replace_bits(&val, pullup, LPI_GPIO_PULL_MASK); @@ -264,6 +268,7 @@ static int lpi_config_set(struct pinctrl_dev *pctldev, unsigned int group, u32p_replace_bits(&val, output_enabled, LPI_GPIO_OE_MASK);

lpi_gpio_write(pctrl, group, LPI_GPIO_CFG_REG, val); + mutex_unlock(&pctrl->lock);

return 0; } @@ -461,7 +466,7 @@ int lpi_pinctrl_probe(struct platform_device *pdev) pctrl->chip.label = dev_name(dev); pctrl->chip.can_sleep = false;

- mutex_init(&pctrl->slew_access_lock); + mutex_init(&pctrl->lock);

pctrl->ctrl = devm_pinctrl_register(dev, &pctrl->desc, pctrl); if (IS_ERR(pctrl->ctrl)) { @@ -483,7 +488,7 @@ int lpi_pinctrl_probe(struct platform_device *pdev) return 0;

err_pinctrl: - mutex_destroy(&pctrl->slew_access_lock); + mutex_destroy(&pctrl->lock); clk_bulk_disable_unprepare(MAX_LPI_NUM_CLKS, pctrl->clks);

return ret; @@ -495,7 +500,7 @@ void lpi_pinctrl_remove(struct platform_device *pdev) struct lpi_pinctrl *pctrl = platform_get_drvdata(pdev); int i;

- mutex_destroy(&pctrl->slew_access_lock); + mutex_destroy(&pctrl->lock); clk_bulk_disable_unprepare(MAX_LPI_NUM_CLKS, pctrl->clks);

for (i = 0; i < pctrl->data->npins; i++)