pinctrl: intel: Use raw_spinlock for locking

When running -rt kernel and GPIO interrupt happens we get following

 BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:931
 in_atomic(): 1, irqs_disabled(): 0, pid: 530, name: irq/14-INT3452:
 Preemption disabled at:[<ffffffff810b4dab>] handle_edge_irq+0x1b/0x190

 CPU: 0 PID: 530 Comm: irq/14-INT3452: Not tainted 4.6.2-rt5 #1060
  0000000000000000 ffff88007a257d58 ffffffff812d8494 0000000000000000
  ffff88017a330000 ffff88007a257d78 ffffffff81083a11 ffff88007a252430
  ffff88007a252430 ffff88007a257d90 ffffffff8167ef20 000000000000001a
 Call Trace:
  [<ffffffff812d8494>] dump_stack+0x4f/0x6b
  [<ffffffff81083a11>] ___might_sleep+0xe1/0x160
  [<ffffffff8167ef20>] rt_spin_lock+0x20/0x50
  [<ffffffff81308c6d>] intel_gpio_irq_ack+0x2d/0x80
  [<ffffffff810b4e0b>] handle_edge_irq+0x7b/0x190
  [<ffffffff810b0d82>] generic_handle_irq+0x22/0x30
  [<ffffffff81307abc>] intel_gpio_irq+0xdc/0x150
  [<ffffffff810b2293>] irq_forced_thread_fn+0x23/0x70
  [<ffffffff810b250b>] irq_thread+0x13b/0x1d0
  [<ffffffff8167b844>] ? __schedule+0x2e4/0x5a0
  [<ffffffff810b2270>] ? irq_finalize_oneshot.part.37+0xd0/0xd0
  [<ffffffff810b25a0>] ? irq_thread+0x1d0/0x1d0
  [<ffffffff810b23d0>] ? wake_threads_waitq+0x30/0x30
  [<ffffffff8107e624>] kthread+0xd4/0xf0
  [<ffffffff8167ec27>] ? _raw_spin_unlock_irq+0x17/0x40
  [<ffffffff8167f592>] ret_from_fork+0x22/0x40
  [<ffffffff8107e550>] ? kthread_worker_fn+0x190/0x190

The reason why this happens is because intel_gpio_irq_ack() is called with
desc->lock raw_spinlock locked which cannot sleep but our normal spinlock
(which is converted to rtmutex in -rt) is allowed to sleep. This causes
might_sleep() to trigger.

Fix this by converting the normal spinlock to a raw_spinlock.

Reported-by: Kim Tatt Chuah <kim.tatt.chuah@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/pinctrl/intel/pinctrl-intel.c b/drivers/pinctrl/intel/pinctrl-intel.c
index 3584e50..f1b14f2 100644 (file)
--- a/drivers/pinctrl/intel/pinctrl-intel.c
+++ b/drivers/pinctrl/intel/pinctrl-intel.c
@@ -89,7 +89,7 @@ struct intel_pinctrl_context {
  */
 struct intel_pinctrl {
        struct device *dev;
-       spinlock_t lock;
+       raw_spinlock_t lock;
        struct pinctrl_desc pctldesc;
        struct pinctrl_dev *pctldev;
        struct gpio_chip chip;
@@ -318,7 +318,7 @@ static int intel_pinmux_set_mux(struct pinctrl_dev *pctldev, unsigned function,
        unsigned long flags;
        int i;
 
-       spin_lock_irqsave(&pctrl->lock, flags);
+       raw_spin_lock_irqsave(&pctrl->lock, flags);
 
        /*
         * All pins in the groups needs to be accessible and writable
@@ -326,7 +326,7 @@ static int intel_pinmux_set_mux(struct pinctrl_dev *pctldev, unsigned function,
         */
        for (i = 0; i < grp->npins; i++) {
                if (!intel_pad_usable(pctrl, grp->pins[i])) {
-                       spin_unlock_irqrestore(&pctrl->lock, flags);
+                       raw_spin_unlock_irqrestore(&pctrl->lock, flags);
                        return -EBUSY;
                }
        }
@@ -345,7 +345,7 @@ static int intel_pinmux_set_mux(struct pinctrl_dev *pctldev, unsigned function,
                writel(value, padcfg0);
        }
 
-       spin_unlock_irqrestore(&pctrl->lock, flags);
+       raw_spin_unlock_irqrestore(&pctrl->lock, flags);
 
        return 0;
 }
@@ -359,10 +359,10 @@ static int intel_gpio_request_enable(struct pinctrl_dev *pctldev,
        unsigned long flags;
        u32 value;
 
-       spin_lock_irqsave(&pctrl->lock, flags);
+       raw_spin_lock_irqsave(&pctrl->lock, flags);
 
        if (!intel_pad_usable(pctrl, pin)) {
-               spin_unlock_irqrestore(&pctrl->lock, flags);
+               raw_spin_unlock_irqrestore(&pctrl->lock, flags);
                return -EBUSY;
        }
 
@@ -377,7 +377,7 @@ static int intel_gpio_request_enable(struct pinctrl_dev *pctldev,
        value |= PADCFG0_GPIOTXDIS;
        writel(value, padcfg0);
 
-       spin_unlock_irqrestore(&pctrl->lock, flags);
+       raw_spin_unlock_irqrestore(&pctrl->lock, flags);
 
        return 0;
 }
@@ -391,7 +391,7 @@ static int intel_gpio_set_direction(struct pinctrl_dev *pctldev,
        unsigned long flags;
        u32 value;
 
-       spin_lock_irqsave(&pctrl->lock, flags);
+       raw_spin_lock_irqsave(&pctrl->lock, flags);
 
        padcfg0 = intel_get_padcfg(pctrl, pin, PADCFG0);
 
@@ -402,7 +402,7 @@ static int intel_gpio_set_direction(struct pinctrl_dev *pctldev,
                value &= ~PADCFG0_GPIOTXDIS;
        writel(value, padcfg0);
 
-       spin_unlock_irqrestore(&pctrl->lock, flags);
+       raw_spin_unlock_irqrestore(&pctrl->lock, flags);
 
        return 0;
 }
@@ -490,7 +490,7 @@ static int intel_config_set_pull(struct intel_pinctrl *pctrl, unsigned pin,
        int ret = 0;
        u32 value;
 
-       spin_lock_irqsave(&pctrl->lock, flags);
+       raw_spin_lock_irqsave(&pctrl->lock, flags);
 
        padcfg1 = intel_get_padcfg(pctrl, pin, PADCFG1);
        value = readl(padcfg1);
@@ -544,7 +544,7 @@ static int intel_config_set_pull(struct intel_pinctrl *pctrl, unsigned pin,
        if (!ret)
                writel(value, padcfg1);
 
-       spin_unlock_irqrestore(&pctrl->lock, flags);
+       raw_spin_unlock_irqrestore(&pctrl->lock, flags);
 
        return ret;
 }
@@ -611,14 +611,14 @@ static void intel_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
                unsigned long flags;
                u32 padcfg0;
 
-               spin_lock_irqsave(&pctrl->lock, flags);
+               raw_spin_lock_irqsave(&pctrl->lock, flags);
                padcfg0 = readl(reg);
                if (value)
                        padcfg0 |= PADCFG0_GPIOTXSTATE;
                else
                        padcfg0 &= ~PADCFG0_GPIOTXSTATE;
                writel(padcfg0, reg);
-               spin_unlock_irqrestore(&pctrl->lock, flags);
+               raw_spin_unlock_irqrestore(&pctrl->lock, flags);
        }
 }
 
@@ -651,7 +651,7 @@ static void intel_gpio_irq_ack(struct irq_data *d)
        const struct intel_community *community;
        unsigned pin = irqd_to_hwirq(d);
 
-       spin_lock(&pctrl->lock);
+       raw_spin_lock(&pctrl->lock);
 
        community = intel_get_community(pctrl, pin);
        if (community) {
@@ -662,7 +662,7 @@ static void intel_gpio_irq_ack(struct irq_data *d)
                writel(BIT(gpp_offset), community->regs + GPI_IS + gpp * 4);
        }
 
-       spin_unlock(&pctrl->lock);
+       raw_spin_unlock(&pctrl->lock);
 }
 
 static void intel_gpio_irq_enable(struct irq_data *d)
@@ -673,7 +673,7 @@ static void intel_gpio_irq_enable(struct irq_data *d)
        unsigned pin = irqd_to_hwirq(d);
        unsigned long flags;
 
-       spin_lock_irqsave(&pctrl->lock, flags);
+       raw_spin_lock_irqsave(&pctrl->lock, flags);
 
        community = intel_get_community(pctrl, pin);
        if (community) {
@@ -691,7 +691,7 @@ static void intel_gpio_irq_enable(struct irq_data *d)
                writel(value, community->regs + community->ie_offset + gpp * 4);
        }
 
-       spin_unlock_irqrestore(&pctrl->lock, flags);
+       raw_spin_unlock_irqrestore(&pctrl->lock, flags);
 }
 
 static void intel_gpio_irq_mask_unmask(struct irq_data *d, bool mask)
@@ -702,7 +702,7 @@ static void intel_gpio_irq_mask_unmask(struct irq_data *d, bool mask)
        unsigned pin = irqd_to_hwirq(d);
        unsigned long flags;
 
-       spin_lock_irqsave(&pctrl->lock, flags);
+       raw_spin_lock_irqsave(&pctrl->lock, flags);
 
        community = intel_get_community(pctrl, pin);
        if (community) {
@@ -721,7 +721,7 @@ static void intel_gpio_irq_mask_unmask(struct irq_data *d, bool mask)
                writel(value, reg);
        }
 
-       spin_unlock_irqrestore(&pctrl->lock, flags);
+       raw_spin_unlock_irqrestore(&pctrl->lock, flags);
 }
 
 static void intel_gpio_irq_mask(struct irq_data *d)
@@ -757,7 +757,7 @@ static int intel_gpio_irq_type(struct irq_data *d, unsigned type)
                return -EPERM;
        }
 
-       spin_lock_irqsave(&pctrl->lock, flags);
+       raw_spin_lock_irqsave(&pctrl->lock, flags);
 
        value = readl(reg);
 
@@ -784,7 +784,7 @@ static int intel_gpio_irq_type(struct irq_data *d, unsigned type)
        else if (type & IRQ_TYPE_LEVEL_MASK)
                irq_set_handler_locked(d, handle_level_irq);
 
-       spin_unlock_irqrestore(&pctrl->lock, flags);
+       raw_spin_unlock_irqrestore(&pctrl->lock, flags);
 
        return 0;
 }
@@ -995,7 +995,7 @@ int intel_pinctrl_probe(struct platform_device *pdev,
 
        pctrl->dev = &pdev->dev;
        pctrl->soc = soc_data;
-       spin_lock_init(&pctrl->lock);
+       raw_spin_lock_init(&pctrl->lock);
 
        /*
         * Make a copy of the communities which we can use to hold pointers