[PATCH 4.4 018/138] pinctrl: cherryview: prevent concurrent access to GPIO controllers

Greg Kroah-Hartman
2016-08-18T14:01:16Z

From: Dan O'Donovan <dan@emutex.com>

commit 0bd50d719b004110e791800450ad204399100a86 upstream.

Due to a silicon issue on the Atom X5-Z8000 "Cherry Trail" processor
series, a common lock must be used to prevent concurrent accesses
across the 4 GPIO controllers managed by this driver.

See Intel Atom Z8000 Processor Series Specification Update
(Rev. 005), errata #CHT34, for further information.

Signed-off-by: Dan O'Donovan <dan@emutex.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/pinctrl/intel/pinctrl-cherryview.c | 80 +++++++++++++++--------------
1 file changed, 44 insertions(+), 36 deletions(-)

--- a/drivers/pinctrl/intel/pinctrl-cherryview.c
+++ b/drivers/pinctrl/intel/pinctrl-cherryview.c
@@ -160,7 +160,6 @@ struct chv_pin_context {
* @pctldev: Pointer to the pin controller device
* @chip: GPIO chip in this pin controller
* @regs: MMIO registers
- * @lock: Lock to serialize register accesses
* @intr_lines: Stores mapping between 16 HW interrupt wires and GPIO
* offset (in GPIO number space)
* @community: Community this pinctrl instance represents
@@ -174,7 +173,6 @@ struct chv_pinctrl {
struct pinctrl_dev *pctldev;
struct gpio_chip chip;
void __iomem *regs;
- raw_spinlock_t lock;
unsigned intr_lines[16];
const struct chv_community *community;
u32 saved_intmask;
@@ -659,6 +657,17 @@ static const struct chv_community *chv_c
&southeast_community,
};

+/*
+ * Lock to serialize register accesses
+ *
+ * Due to a silicon issue, a shared lock must be used to prevent
+ * concurrent accesses across the 4 GPIO controllers.
+ *
+ * See Intel Atom Z8000 Processor Series Specification Update (Rev. 005),
+ * errata #CHT34, for further information.
+ */
+static DEFINE_RAW_SPINLOCK(chv_lock);
+
static void __iomem *chv_padreg(struct chv_pinctrl *pctrl, unsigned offset,
unsigned reg)
{
@@ -720,13 +729,13 @@ static void chv_pin_dbg_show(struct pinc
u32 ctrl0, ctrl1;
bool locked;

- raw_spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&chv_lock, flags);

ctrl0 = readl(chv_padreg(pctrl, offset, CHV_PADCTRL0));
ctrl1 = readl(chv_padreg(pctrl, offset, CHV_PADCTRL1));
locked = chv_pad_locked(pctrl, offset);

- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);

if (ctrl0 & CHV_PADCTRL0_GPIOEN) {
seq_puts(s, "GPIO ");
@@ -789,14 +798,14 @@ static int chv_pinmux_set_mux(struct pin

grp = &pctrl->community->groups[group];

- raw_spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&chv_lock, flags);

/* Check first that the pad is not locked */
for (i = 0; i < grp->npins; i++) {
if (chv_pad_locked(pctrl, grp->pins[i])) {
dev_warn(pctrl->dev, "unable to set mode for locked pin %u\n",
grp->pins[i]);
- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);
return -EBUSY;
}
}
@@ -839,7 +848,7 @@ static int chv_pinmux_set_mux(struct pin
pin, altfunc->mode, altfunc->invert_oe ? "" : "not ");
}

- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);

return 0;
}
@@ -853,13 +862,13 @@ static int chv_gpio_request_enable(struc
void __iomem *reg;
u32 value;

- raw_spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&chv_lock, flags);

if (chv_pad_locked(pctrl, offset)) {
value = readl(chv_padreg(pctrl, offset, CHV_PADCTRL0));
if (!(value & CHV_PADCTRL0_GPIOEN)) {
/* Locked so cannot enable */
- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);
return -EBUSY;
}
} else {
@@ -899,7 +908,7 @@ static int chv_gpio_request_enable(struc
chv_writel(value, reg);
}

- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);

return 0;
}
@@ -913,13 +922,13 @@ static void chv_gpio_disable_free(struct
void __iomem *reg;
u32 value;

- raw_spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&chv_lock, flags);

reg = chv_padreg(pctrl, offset, CHV_PADCTRL0);
value = readl(reg) & ~CHV_PADCTRL0_GPIOEN;
chv_writel(value, reg);

- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);
}

static int chv_gpio_set_direction(struct pinctrl_dev *pctldev,
@@ -931,7 +940,7 @@ static int chv_gpio_set_direction(struct
unsigned long flags;
u32 ctrl0;

- raw_spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&chv_lock, flags);

ctrl0 = readl(reg) & ~CHV_PADCTRL0_GPIOCFG_MASK;
if (input)
@@ -940,7 +949,7 @@ static int chv_gpio_set_direction(struct
ctrl0 |= CHV_PADCTRL0_GPIOCFG_GPO << CHV_PADCTRL0_GPIOCFG_SHIFT;
chv_writel(ctrl0, reg);

- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);

return 0;
}
@@ -965,10 +974,10 @@ static int chv_config_get(struct pinctrl
u16 arg = 0;
u32 term;

- raw_spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&chv_lock, flags);
ctrl0 = readl(chv_padreg(pctrl, pin, CHV_PADCTRL0));
ctrl1 = readl(chv_padreg(pctrl, pin, CHV_PADCTRL1));
- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);

term = (ctrl0 & CHV_PADCTRL0_TERM_MASK) >> CHV_PADCTRL0_TERM_SHIFT;

@@ -1042,7 +1051,7 @@ static int chv_config_set_pull(struct ch
unsigned long flags;
u32 ctrl0, pull;

- raw_spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&chv_lock, flags);
ctrl0 = readl(reg);

switch (param) {
@@ -1065,7 +1074,7 @@ static int chv_config_set_pull(struct ch
pull = CHV_PADCTRL0_TERM_20K << CHV_PADCTRL0_TERM_SHIFT;
break;
default:
- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);
return -EINVAL;
}

@@ -1083,7 +1092,7 @@ static int chv_config_set_pull(struct ch
pull = CHV_PADCTRL0_TERM_20K << CHV_PADCTRL0_TERM_SHIFT;
break;
default:
- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);
return -EINVAL;
}

@@ -1091,12 +1100,12 @@ static int chv_config_set_pull(struct ch
break;

default:
- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);
return -EINVAL;
}

chv_writel(ctrl0, reg);
- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);

return 0;
}
@@ -1162,9 +1171,9 @@ static int chv_gpio_get(struct gpio_chip
unsigned long flags;
u32 ctrl0, cfg;

- raw_spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&chv_lock, flags);
ctrl0 = readl(chv_padreg(pctrl, pin, CHV_PADCTRL0));
- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);

cfg = ctrl0 & CHV_PADCTRL0_GPIOCFG_MASK;
cfg >>= CHV_PADCTRL0_GPIOCFG_SHIFT;
@@ -1182,7 +1191,7 @@ static void chv_gpio_set(struct gpio_chi
void __iomem *reg;
u32 ctrl0;

- raw_spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&chv_lock, flags);

reg = chv_padreg(pctrl, pin, CHV_PADCTRL0);
ctrl0 = readl(reg);
@@ -1194,7 +1203,7 @@ static void chv_gpio_set(struct gpio_chi

chv_writel(ctrl0, reg);

- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);
}

static int chv_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
@@ -1204,9 +1213,9 @@ static int chv_gpio_get_direction(struct
u32 ctrl0, direction;
unsigned long flags;

- raw_spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&chv_lock, flags);
ctrl0 = readl(chv_padreg(pctrl, pin, CHV_PADCTRL0));
- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);

direction = ctrl0 & CHV_PADCTRL0_GPIOCFG_MASK;
direction >>= CHV_PADCTRL0_GPIOCFG_SHIFT;
@@ -1244,14 +1253,14 @@ static void chv_gpio_irq_ack(struct irq_
int pin = chv_gpio_offset_to_pin(pctrl, irqd_to_hwirq(d));
u32 intr_line;

- raw_spin_lock(&pctrl->lock);
+ raw_spin_lock(&chv_lock);

intr_line = readl(chv_padreg(pctrl, pin, CHV_PADCTRL0));
intr_line &= CHV_PADCTRL0_INTSEL_MASK;
intr_line >>= CHV_PADCTRL0_INTSEL_SHIFT;
chv_writel(BIT(intr_line), pctrl->regs + CHV_INTSTAT);

- raw_spin_unlock(&pctrl->lock);
+ raw_spin_unlock(&chv_lock);
}

static void chv_gpio_irq_mask_unmask(struct irq_data *d, bool mask)
@@ -1262,7 +1271,7 @@ static void chv_gpio_irq_mask_unmask(str
u32 value, intr_line;
unsigned long flags;

- raw_spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&chv_lock, flags);

intr_line = readl(chv_padreg(pctrl, pin, CHV_PADCTRL0));
intr_line &= CHV_PADCTRL0_INTSEL_MASK;
@@ -1275,7 +1284,7 @@ static void chv_gpio_irq_mask_unmask(str
value |= BIT(intr_line);
chv_writel(value, pctrl->regs + CHV_INTMASK);

- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);
}

static void chv_gpio_irq_mask(struct irq_data *d)
@@ -1309,7 +1318,7 @@ static unsigned chv_gpio_irq_startup(str
unsigned long flags;
u32 intsel, value;

- raw_spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&chv_lock, flags);
intsel = readl(chv_padreg(pctrl, pin, CHV_PADCTRL0));
intsel &= CHV_PADCTRL0_INTSEL_MASK;
intsel >>= CHV_PADCTRL0_INTSEL_SHIFT;
@@ -1324,7 +1333,7 @@ static unsigned chv_gpio_irq_startup(str
irq_set_handler_locked(d, handler);
pctrl->intr_lines[intsel] = offset;
}
- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);
}

chv_gpio_irq_unmask(d);
@@ -1340,7 +1349,7 @@ static int chv_gpio_irq_type(struct irq_
unsigned long flags;
u32 value;

- raw_spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&chv_lock, flags);

/*
* Pins which can be used as shared interrupt are configured in
@@ -1389,7 +1398,7 @@ static int chv_gpio_irq_type(struct irq_
else if (type & IRQ_TYPE_LEVEL_MASK)
irq_set_handler_locked(d, handle_level_irq);

- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&chv_lock, flags);

return 0;
}
@@ -1501,7 +1510,6 @@ static int chv_pinctrl_probe(struct plat
if (i == ARRAY_SIZE(chv_communities))
return -ENODEV;

- raw_spin_lock_init(&pctrl->lock);
pctrl->dev = &pdev->dev;

#ifdef CONFIG_PM_SLEEP