gpio: bcm-kona: make use of raw_spinlock variants

The bcm-kona gpio driver currently implements an irq_chip for handling
interrupts; due to how irq_chip handling is done, it's necessary for the
irq_chip methods to be invoked from hardirq context, even on a a
real-time kernel.  Because the spinlock_t type becomes a "sleeping"
spinlock w/ RT kernels, it is not suitable to be used with irq_chips.

A quick audit of the operations under the lock reveal that they do only
minimal, bounded work, and are therefore safe to do under a raw spinlock.

Signed-off-by: Julia Cartwright <julia@ni.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpio-bcm-kona.c b/drivers/gpio/gpio-bcm-kona.c
index 41d0ac1425803eeeb5098c7a6f73d1c35aa17ce1..dfcf56ee3c6181fc64d0a074e2f5659fec35a6d8 100644 (file)
--- a/drivers/gpio/gpio-bcm-kona.c
+++ b/drivers/gpio/gpio-bcm-kona.c
@@ -67,7 +67,7 @@
 struct bcm_kona_gpio {
        void __iomem *reg_base;
        int num_bank;
-       spinlock_t lock;
+       raw_spinlock_t lock;
        struct gpio_chip gpio_chip;
        struct irq_domain *irq_domain;
        struct bcm_kona_gpio_bank *banks;
@@ -95,13 +95,13 @@ static void bcm_kona_gpio_lock_gpio(struct bcm_kona_gpio *kona_gpio,
        unsigned long flags;
        int bank_id = GPIO_BANK(gpio);
 
-       spin_lock_irqsave(&kona_gpio->lock, flags);
+       raw_spin_lock_irqsave(&kona_gpio->lock, flags);
 
        val = readl(kona_gpio->reg_base + GPIO_PWD_STATUS(bank_id));
        val |= BIT(gpio);
        bcm_kona_gpio_write_lock_regs(kona_gpio->reg_base, bank_id, val);
 
-       spin_unlock_irqrestore(&kona_gpio->lock, flags);
+       raw_spin_unlock_irqrestore(&kona_gpio->lock, flags);
 }
 
 static void bcm_kona_gpio_unlock_gpio(struct bcm_kona_gpio *kona_gpio,
@@ -111,13 +111,13 @@ static void bcm_kona_gpio_unlock_gpio(struct bcm_kona_gpio *kona_gpio,
        unsigned long flags;
        int bank_id = GPIO_BANK(gpio);
 
-       spin_lock_irqsave(&kona_gpio->lock, flags);
+       raw_spin_lock_irqsave(&kona_gpio->lock, flags);
 
        val = readl(kona_gpio->reg_base + GPIO_PWD_STATUS(bank_id));
        val &= ~BIT(gpio);
        bcm_kona_gpio_write_lock_regs(kona_gpio->reg_base, bank_id, val);
 
-       spin_unlock_irqrestore(&kona_gpio->lock, flags);
+       raw_spin_unlock_irqrestore(&kona_gpio->lock, flags);
 }
 
 static int bcm_kona_gpio_get_dir(struct gpio_chip *chip, unsigned gpio)
@@ -141,7 +141,7 @@ static void bcm_kona_gpio_set(struct gpio_chip *chip, unsigned gpio, int value)
 
        kona_gpio = gpiochip_get_data(chip);
        reg_base = kona_gpio->reg_base;
-       spin_lock_irqsave(&kona_gpio->lock, flags);
+       raw_spin_lock_irqsave(&kona_gpio->lock, flags);
 
        /* this function only applies to output pin */
        if (bcm_kona_gpio_get_dir(chip, gpio) == GPIOF_DIR_IN)
@@ -154,7 +154,7 @@ static void bcm_kona_gpio_set(struct gpio_chip *chip, unsigned gpio, int value)
        writel(val, reg_base + reg_offset);
 
 out:
-       spin_unlock_irqrestore(&kona_gpio->lock, flags);
+       raw_spin_unlock_irqrestore(&kona_gpio->lock, flags);
 }
 
 static int bcm_kona_gpio_get(struct gpio_chip *chip, unsigned gpio)
@@ -168,7 +168,7 @@ static int bcm_kona_gpio_get(struct gpio_chip *chip, unsigned gpio)
 
        kona_gpio = gpiochip_get_data(chip);
        reg_base = kona_gpio->reg_base;
-       spin_lock_irqsave(&kona_gpio->lock, flags);
+       raw_spin_lock_irqsave(&kona_gpio->lock, flags);
 
        if (bcm_kona_gpio_get_dir(chip, gpio) == GPIOF_DIR_IN)
                reg_offset = GPIO_IN_STATUS(bank_id);
@@ -178,7 +178,7 @@ static int bcm_kona_gpio_get(struct gpio_chip *chip, unsigned gpio)
        /* read the GPIO bank status */
        val = readl(reg_base + reg_offset);
 
-       spin_unlock_irqrestore(&kona_gpio->lock, flags);
+       raw_spin_unlock_irqrestore(&kona_gpio->lock, flags);
 
        /* return the specified bit status */
        return !!(val & BIT(bit));
@@ -208,14 +208,14 @@ static int bcm_kona_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
 
        kona_gpio = gpiochip_get_data(chip);
        reg_base = kona_gpio->reg_base;
-       spin_lock_irqsave(&kona_gpio->lock, flags);
+       raw_spin_lock_irqsave(&kona_gpio->lock, flags);
 
        val = readl(reg_base + GPIO_CONTROL(gpio));
        val &= ~GPIO_GPCTR0_IOTR_MASK;
        val |= GPIO_GPCTR0_IOTR_CMD_INPUT;
        writel(val, reg_base + GPIO_CONTROL(gpio));
 
-       spin_unlock_irqrestore(&kona_gpio->lock, flags);
+       raw_spin_unlock_irqrestore(&kona_gpio->lock, flags);
 
        return 0;
 }
@@ -232,7 +232,7 @@ static int bcm_kona_gpio_direction_output(struct gpio_chip *chip,
 
        kona_gpio = gpiochip_get_data(chip);
        reg_base = kona_gpio->reg_base;
-       spin_lock_irqsave(&kona_gpio->lock, flags);
+       raw_spin_lock_irqsave(&kona_gpio->lock, flags);
 
        val = readl(reg_base + GPIO_CONTROL(gpio));
        val &= ~GPIO_GPCTR0_IOTR_MASK;
@@ -244,7 +244,7 @@ static int bcm_kona_gpio_direction_output(struct gpio_chip *chip,
        val |= BIT(bit);
        writel(val, reg_base + reg_offset);
 
-       spin_unlock_irqrestore(&kona_gpio->lock, flags);
+       raw_spin_unlock_irqrestore(&kona_gpio->lock, flags);
 
        return 0;
 }
@@ -288,7 +288,7 @@ static int bcm_kona_gpio_set_debounce(struct gpio_chip *chip, unsigned gpio,
        }
 
        /* spin lock for read-modify-write of the GPIO register */
-       spin_lock_irqsave(&kona_gpio->lock, flags);
+       raw_spin_lock_irqsave(&kona_gpio->lock, flags);
 
        val = readl(reg_base + GPIO_CONTROL(gpio));
        val &= ~GPIO_GPCTR0_DBR_MASK;
@@ -303,7 +303,7 @@ static int bcm_kona_gpio_set_debounce(struct gpio_chip *chip, unsigned gpio,
 
        writel(val, reg_base + GPIO_CONTROL(gpio));
 
-       spin_unlock_irqrestore(&kona_gpio->lock, flags);
+       raw_spin_unlock_irqrestore(&kona_gpio->lock, flags);
 
        return 0;
 }
@@ -347,13 +347,13 @@ static void bcm_kona_gpio_irq_ack(struct irq_data *d)
 
        kona_gpio = irq_data_get_irq_chip_data(d);
        reg_base = kona_gpio->reg_base;
-       spin_lock_irqsave(&kona_gpio->lock, flags);
+       raw_spin_lock_irqsave(&kona_gpio->lock, flags);
 
        val = readl(reg_base + GPIO_INT_STATUS(bank_id));
        val |= BIT(bit);
        writel(val, reg_base + GPIO_INT_STATUS(bank_id));
 
-       spin_unlock_irqrestore(&kona_gpio->lock, flags);
+       raw_spin_unlock_irqrestore(&kona_gpio->lock, flags);
 }
 
 static void bcm_kona_gpio_irq_mask(struct irq_data *d)
@@ -368,13 +368,13 @@ static void bcm_kona_gpio_irq_mask(struct irq_data *d)
 
        kona_gpio = irq_data_get_irq_chip_data(d);
        reg_base = kona_gpio->reg_base;
-       spin_lock_irqsave(&kona_gpio->lock, flags);
+       raw_spin_lock_irqsave(&kona_gpio->lock, flags);
 
        val = readl(reg_base + GPIO_INT_MASK(bank_id));
        val |= BIT(bit);
        writel(val, reg_base + GPIO_INT_MASK(bank_id));
 
-       spin_unlock_irqrestore(&kona_gpio->lock, flags);
+       raw_spin_unlock_irqrestore(&kona_gpio->lock, flags);
 }
 
 static void bcm_kona_gpio_irq_unmask(struct irq_data *d)
@@ -389,13 +389,13 @@ static void bcm_kona_gpio_irq_unmask(struct irq_data *d)
 
        kona_gpio = irq_data_get_irq_chip_data(d);
        reg_base = kona_gpio->reg_base;
-       spin_lock_irqsave(&kona_gpio->lock, flags);
+       raw_spin_lock_irqsave(&kona_gpio->lock, flags);
 
        val = readl(reg_base + GPIO_INT_MSKCLR(bank_id));
        val |= BIT(bit);
        writel(val, reg_base + GPIO_INT_MSKCLR(bank_id));
 
-       spin_unlock_irqrestore(&kona_gpio->lock, flags);
+       raw_spin_unlock_irqrestore(&kona_gpio->lock, flags);
 }
 
 static int bcm_kona_gpio_irq_set_type(struct irq_data *d, unsigned int type)
@@ -431,14 +431,14 @@ static int bcm_kona_gpio_irq_set_type(struct irq_data *d, unsigned int type)
                return -EINVAL;
        }
 
-       spin_lock_irqsave(&kona_gpio->lock, flags);
+       raw_spin_lock_irqsave(&kona_gpio->lock, flags);
 
        val = readl(reg_base + GPIO_CONTROL(gpio));
        val &= ~GPIO_GPCTR0_ITR_MASK;
        val |= lvl_type << GPIO_GPCTR0_ITR_SHIFT;
        writel(val, reg_base + GPIO_CONTROL(gpio));
 
-       spin_unlock_irqrestore(&kona_gpio->lock, flags);
+       raw_spin_unlock_irqrestore(&kona_gpio->lock, flags);
 
        return 0;
 }
@@ -655,7 +655,7 @@ static int bcm_kona_gpio_probe(struct platform_device *pdev)
                                                 bank);
        }
 
-       spin_lock_init(&kona_gpio->lock);
+       raw_spin_lock_init(&kona_gpio->lock);
 
        return 0;