Re: [PATCH v6 1/5] pinctrl: mediatek: Check gpio pin number and use binary search in mtk_hw_pin_field_lookup()

From: Sean Wang
Date: Fri Sep 27 2019 - 13:24:04 EST

On Thu, Sep 26, 2019 at 10:14 PM Light Hsieh <light.hsieh@xxxxxxxxxxxx> wrote:
>
> Dear reviewers:
>
> Patch v6 improves v5 by:
>
> 1.in mtk_pinconf_get() and mtk_pinconf_set() @pinctrl-paris.c:
> * check if pin is in range before using pin as array index of
> hw->soc->pins[]
> 2.in mtk_pin_field_lookup() @pinctrl-mtk-common-v2.c:
> * declear start, end, check as signed integer instead of unsigned
> integer. Otherwise, kernel fault will occur when s_pin field of
> first entry of a mtk_pin_field_calc[] array is not 0.
>

And for review these patches easily, you should put the changes
history to the cover letter.

> On Fri, 2019-09-27 at 13:02 +0800, Light Hsieh wrote:
> > 1. Check if gpio pin number is in valid range to prevent from get invalid
> > pointer 'desc' in the following code:
> > desc = (const struct mtk_pin_desc *)&hw->soc->pins[gpio];
> >
> > 2. Use binary search in mtk_hw_pin_field_lookup()
> > Modify mtk_hw_pin_field_lookup() to use binary search for accelerating
> > search.
> >

You almost forgot to add the tags from you and the reviewers' feedback.

> > ---
> > drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c | 25 +++++++++++++++++++-----
> > drivers/pinctrl/mediatek/pinctrl-paris.c | 25 ++++++++++++++++++++++++
> > 2 files changed, 45 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
> > index 20e1c89..8077855 100644
> > --- a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
> > +++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
> > @@ -68,7 +68,8 @@ static int mtk_hw_pin_field_lookup(struct mtk_pinctrl *hw,
> > {
> > const struct mtk_pin_field_calc *c, *e;
> > const struct mtk_pin_reg_calc *rc;
> > - u32 bits;
> > + u32 bits, found = 0;

the type of found seems to be a bool

> > + int start = 0, end, check;
> >
> > if (hw->soc->reg_cal && hw->soc->reg_cal[field].range) {
> > rc = &hw->soc->reg_cal[field];
> > @@ -79,21 +80,32 @@ static int mtk_hw_pin_field_lookup(struct mtk_pinctrl *hw,
> > return -ENOTSUPP;
> > }
> >
> > + end = rc->nranges - 1;
> > c = rc->range;
> > e = c + rc->nranges;
> >
> > - while (c < e) {
> > - if (desc->number >= c->s_pin && desc->number <= c->e_pin)
> > + while (start <= end) {
> > + check = (start + end) >> 1;
> > + if (desc->number >= rc->range[check].s_pin
> > + && desc->number <= rc->range[check].e_pin) {
> > + found = 1;
> > break;
> > - c++;
> > + } else if (start == end)
> > + break;
> > + else if (desc->number < rc->range[check].s_pin)
> > + end = check - 1;
> > + else
> > + start = check + 1;
> > }
> >

yuh, it is good to do do a binary search here

> > - if (c >= e) {
> > + if (!found) {
> > dev_dbg(hw->dev, "Not support field %d for pin = %d (%s)\n",
> > field, desc->number, desc->name);
> > return -ENOTSUPP;
> > }
> >
> > + c = rc->range + check;
> > +
> > if (c->i_base > hw->nbase - 1) {
> > dev_err(hw->dev,
> > "Invalid base for field %d for pin = %d (%s)\n",
> > @@ -182,6 +194,9 @@ int mtk_hw_set_value(struct mtk_pinctrl *hw, const struct mtk_pin_desc *desc,
> > if (err)
> > return err;
> >
> > + if (value < 0 || value > pf.mask)
> > + return -EINVAL;
> > +
> > if (!pf.next)
> > mtk_rmw(hw, pf.index, pf.offset, pf.mask << pf.bitpos,
> > (value & pf.mask) << pf.bitpos);
> > diff --git a/drivers/pinctrl/mediatek/pinctrl-paris.c b/drivers/pinctrl/mediatek/pinctrl-paris.c
> > index 923264d..3e13ae7 100644
> > --- a/drivers/pinctrl/mediatek/pinctrl-paris.c
> > +++ b/drivers/pinctrl/mediatek/pinctrl-paris.c
> > @@ -81,6 +81,8 @@ static int mtk_pinconf_get(struct pinctrl_dev *pctldev,
> > int val, val2, err, reg, ret = 1;
> > const struct mtk_pin_desc *desc;
> >
> > + if (pin >= hw->soc->npins)
> > + return -EINVAL;
> > desc = (const struct mtk_pin_desc *)&hw->soc->pins[pin];
> >
> > switch (param) {
> > @@ -206,6 +208,10 @@ static int mtk_pinconf_set(struct pinctrl_dev *pctldev, unsigned int pin,
> > int err = 0;
> > u32 reg;
> >
> > + if (pin >= hw->soc->npins) {
> > + err = -EINVAL;
> > + goto err;
> > + }
> > desc = (const struct mtk_pin_desc *)&hw->soc->pins[pin];
> >
> > switch ((u32)param) {
> > @@ -693,6 +699,9 @@ static int mtk_gpio_get_direction(struct gpio_chip *chip, unsigned int gpio)
> > const struct mtk_pin_desc *desc;
> > int value, err;
> >
> > + if (gpio > hw->soc->npins)
> > + return -EINVAL;
> > +
> > desc = (const struct mtk_pin_desc *)&hw->soc->pins[gpio];
> >
> > err = mtk_hw_get_value(hw, desc, PINCTRL_PIN_REG_DIR, &value);
> > @@ -708,6 +717,9 @@ static int mtk_gpio_get(struct gpio_chip *chip, unsigned int gpio)
> > const struct mtk_pin_desc *desc;
> > int value, err;
> >
> > + if (gpio > hw->soc->npins)
> > + return -EINVAL;
> > +
> > desc = (const struct mtk_pin_desc *)&hw->soc->pins[gpio];
> >
> > err = mtk_hw_get_value(hw, desc, PINCTRL_PIN_REG_DI, &value);
> > @@ -722,6 +734,9 @@ static void mtk_gpio_set(struct gpio_chip *chip, unsigned int gpio, int value)
> > struct mtk_pinctrl *hw = gpiochip_get_data(chip);
> > const struct mtk_pin_desc *desc;
> >
> > + if (gpio > hw->soc->npins)
> > + return;
> > +
> > desc = (const struct mtk_pin_desc *)&hw->soc->pins[gpio];
> >
> > mtk_hw_set_value(hw, desc, PINCTRL_PIN_REG_DO, !!value);
> > @@ -729,12 +744,22 @@ static void mtk_gpio_set(struct gpio_chip *chip, unsigned int gpio, int value)
> >
> > static int mtk_gpio_direction_input(struct gpio_chip *chip, unsigned int gpio)
> > {
> > + struct mtk_pinctrl *hw = gpiochip_get_data(chip);
> > +
> > + if (gpio > hw->soc->npins)
> > + return -EINVAL;
> > +
> > return pinctrl_gpio_direction_input(chip->base + gpio);
> > }
> >
> > static int mtk_gpio_direction_output(struct gpio_chip *chip, unsigned int gpio,
> > int value)
> > {
> > + struct mtk_pinctrl *hw = gpiochip_get_data(chip);
> > +
> > + if (gpio > hw->soc->npins)
> > + return -EINVAL;
> > +
> > mtk_gpio_set(chip, gpio, value);
> >
> > return pinctrl_gpio_direction_output(chip->base + gpio);
>
>