[PATCH v4 4/4] pinctrl: rockchip: avoid hardirq-unsafe functions in irq_chip

[John Keeping]

With real-time preemption, regmap functions cannot be used in the
implementation of irq_chip since they use spinlocks which may sleep.

Move the setting of the mux for IRQs to an irq_bus_sync_unlock handler
where we are allowed to sleep.

Signed-off-by: John Keeping <j...@metanate.com>
Reviewed-by: Heiko Stuebner <he...@sntech.de>
Tested-by: Heiko Stuebner <he...@sntech.de>
---
v3: unchanged
v2: unchanged
---
 drivers/pinctrl/pinctrl-rockchip.c | 44 ++++++++++++++++++++++++++++++++++----
 1 file changed, 40 insertions(+), 4 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-rockchip.c 
b/drivers/pinctrl/pinctrl-rockchip.c
index 9dd981ddbb17..f141aa0430b1 100644
--- a/drivers/pinctrl/pinctrl-rockchip.c
+++ b/drivers/pinctrl/pinctrl-rockchip.c
@@ -143,6 +143,9 @@ struct rockchip_drv {
  * @gpio_chip: gpiolib chip
  * @grange: gpio range
  * @slock: spinlock for the gpio bank
+ * @irq_lock: bus lock for irq chip
+ * @new_irqs: newly configured irqs which must be muxed as GPIOs in
+ *     irq_bus_sync_unlock()
  */
 struct rockchip_pin_bank {
        void __iomem                    *reg_base;
@@ -165,6 +168,8 @@ struct rockchip_pin_bank {
        struct pinctrl_gpio_range       grange;
        raw_spinlock_t                  slock;
        u32                             toggle_edge_mode;
+       struct mutex                    irq_lock;
+       u32                             new_irqs;
 };
 
 #define PIN_BANK(id, pins, label)                      \
@@ -2129,11 +2134,12 @@ static int rockchip_irq_set_type(struct irq_data *d, 
unsigned int type)
        int ret;
 
        /* make sure the pin is configured as gpio input */
-       ret = rockchip_set_mux(bank, d->hwirq, RK_FUNC_GPIO);
+       ret = rockchip_verify_mux(bank, d->hwirq, RK_FUNC_GPIO);
        if (ret < 0)
                return ret;
 
-       clk_enable(bank->clk);
+       bank->new_irqs |= mask;
+
        raw_spin_lock_irqsave(&bank->slock, flags);
 
        data = readl_relaxed(bank->reg_base + GPIO_SWPORT_DDR);
@@ -2191,7 +2197,6 @@ static int rockchip_irq_set_type(struct irq_data *d, 
unsigned int type)
        default:
                irq_gc_unlock(gc);
                raw_spin_unlock_irqrestore(&bank->slock, flags);
-               clk_disable(bank->clk);
                return -EINVAL;
        }
 
@@ -2200,7 +2205,6 @@ static int rockchip_irq_set_type(struct irq_data *d, 
unsigned int type)
 
        irq_gc_unlock(gc);
        raw_spin_unlock_irqrestore(&bank->slock, flags);
-       clk_disable(bank->clk);
 
        return 0;
 }
@@ -2244,6 +2248,34 @@ static void rockchip_irq_disable(struct irq_data *d)
        clk_disable(bank->clk);
 }
 
+static void rockchip_irq_bus_lock(struct irq_data *d)
+{
+       struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+       struct rockchip_pin_bank *bank = gc->private;
+
+       clk_enable(bank->clk);
+       mutex_lock(&bank->irq_lock);
+}
+
+static void rockchip_irq_bus_sync_unlock(struct irq_data *d)
+{
+       struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+       struct rockchip_pin_bank *bank = gc->private;
+
+       while (bank->new_irqs) {
+               unsigned int irq = __ffs(bank->new_irqs);
+               int ret;
+
+               ret = rockchip_set_mux(bank, irq, RK_FUNC_GPIO);
+               WARN_ON(ret < 0);
+
+               bank->new_irqs &= ~BIT(irq);
+       }
+
+       mutex_unlock(&bank->irq_lock);
+       clk_disable(bank->clk);
+}
+
 static int rockchip_interrupts_register(struct platform_device *pdev,
                                                struct rockchip_pinctrl *info)
 {
@@ -2310,6 +2342,9 @@ static int rockchip_interrupts_register(struct 
platform_device *pdev,
                gc->chip_types[0].chip.irq_suspend = rockchip_irq_suspend;
                gc->chip_types[0].chip.irq_resume = rockchip_irq_resume;
                gc->chip_types[0].chip.irq_set_type = rockchip_irq_set_type;
+               gc->chip_types[0].chip.irq_bus_lock = rockchip_irq_bus_lock;
+               gc->chip_types[0].chip.irq_bus_sync_unlock =
+                                               rockchip_irq_bus_sync_unlock;
                gc->wake_enabled = IRQ_MSK(bank->nr_pins);
 
                irq_set_chained_handler_and_data(bank->irq,
@@ -2483,6 +2518,7 @@ static struct rockchip_pin_ctrl 
*rockchip_pinctrl_get_soc_data(
                int bank_pins = 0;
 
                raw_spin_lock_init(&bank->slock);
+               mutex_init(&bank->irq_lock);
                bank->drvdata = d;
                bank->pin_base = ctrl->nr_pins;
                ctrl->nr_pins += bank->nr_pins;
-- 
2.12.0.377.gf910686b23.dirty