[PATCH RT 2/8] pinctrl: qcom: Use raw spinlock variants

Steven Rostedt
2017-03-08T20:32:17Z

[-- Attachment #1: 0002-pinctrl-qcom-Use-raw-spinlock-variants.patch --]
[-- Type: text/plain, Size: 8506 bytes --]

3.18.48-rt54-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Julia Cartwright <julia@ni.com>

The MSM pinctrl driver currently implements an irq_chip for handling
GPIO 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.

On real-time kernels, this fixes an OOPs which looks like the following,
as reported by Brian Wrenn:

kernel BUG at kernel/locking/rtmutex.c:1014!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
Modules linked in: spidev_irq(O) smsc75xx wcn36xx [last unloaded: spidev]
CPU: 0 PID: 1163 Comm: irq/144-mmc0 Tainted: G W O 4.4.9-linaro-lt-qcom #1
PC is at rt_spin_lock_slowlock+0x80/0x2d8
LR is at rt_spin_lock_slowlock+0x68/0x2d8
[..]
Call trace:
rt_spin_lock_slowlock
rt_spin_lock
msm_gpio_irq_ack
handle_edge_irq
generic_handle_irq
msm_gpio_irq_handler
generic_handle_irq
__handle_domain_irq
gic_handle_irq

Cc: stable-rt@vger.kernel.org
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Reported-by: Brian Wrenn <dcbrianw@gmail.com>
Tested-by: Brian Wrenn <dcbrianw@gmail.com>
Signed-off-by: Julia Cartwright <julia@ni.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
drivers/pinctrl/qcom/pinctrl-msm.c | 48 +++++++++++++++++++-------------------
1 file changed, 24 insertions(+), 24 deletions(-)

diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
index ed7017df065d..94f1a4fd7681 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -59,7 +59,7 @@ struct msm_pinctrl {
struct notifier_block restart_nb;
int irq;

- spinlock_t lock;
+ raw_spinlock_t lock;

DECLARE_BITMAP(dual_edge_irqs, MAX_NR_GPIO);
DECLARE_BITMAP(enabled_irqs, MAX_NR_GPIO);
@@ -155,14 +155,14 @@ static int msm_pinmux_set_mux(struct pinctrl_dev *pctldev,
if (WARN_ON(i == g->nfuncs))
return -EINVAL;

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

val = readl(pctrl->regs + g->ctl_reg);
val &= ~(0x7 << g->mux_bit);
val |= i << g->mux_bit;
writel(val, pctrl->regs + g->ctl_reg);

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

return 0;
}
@@ -336,14 +336,14 @@ static int msm_config_group_set(struct pinctrl_dev *pctldev,
break;
case PIN_CONFIG_OUTPUT:
/* set output value */
- spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&pctrl->lock, flags);
val = readl(pctrl->regs + g->io_reg);
if (arg)
val |= BIT(g->out_bit);
else
val &= ~BIT(g->out_bit);
writel(val, pctrl->regs + g->io_reg);
- spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&pctrl->lock, flags);

/* enable output */
arg = 1;
@@ -360,12 +360,12 @@ static int msm_config_group_set(struct pinctrl_dev *pctldev,
return -EINVAL;
}

- spin_lock_irqsave(&pctrl->lock, flags);
+ raw_spin_lock_irqsave(&pctrl->lock, flags);
val = readl(pctrl->regs + g->ctl_reg);
val &= ~(mask << bit);
val |= arg << bit;
writel(val, pctrl->regs + g->ctl_reg);
- spin_unlock_irqrestore(&pctrl->lock, flags);
+ raw_spin_unlock_irqrestore(&pctrl->lock, flags);
}

return 0;
@@ -394,13 +394,13 @@ static int msm_gpio_direction_input(struct gpio_chip *chip, unsigned offset)

g = &pctrl->soc->groups[offset];

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

val = readl(pctrl->regs + g->ctl_reg);
val &= ~BIT(g->oe_bit);
writel(val, pctrl->regs + g->ctl_reg);

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

return 0;
}
@@ -414,7 +414,7 @@ static int msm_gpio_direction_output(struct gpio_chip *chip, unsigned offset, in

g = &pctrl->soc->groups[offset];

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

val = readl(pctrl->regs + g->io_reg);
if (value)
@@ -427,7 +427,7 @@ static int msm_gpio_direction_output(struct gpio_chip *chip, unsigned offset, in
val |= BIT(g->oe_bit);
writel(val, pctrl->regs + g->ctl_reg);

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

return 0;
}
@@ -453,7 +453,7 @@ static void msm_gpio_set(struct gpio_chip *chip, unsigned offset, int value)

g = &pctrl->soc->groups[offset];

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

val = readl(pctrl->regs + g->io_reg);
if (value)
@@ -462,7 +462,7 @@ static void msm_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
val &= ~BIT(g->out_bit);
writel(val, pctrl->regs + g->io_reg);

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

static int msm_gpio_request(struct gpio_chip *chip, unsigned offset)
@@ -593,7 +593,7 @@ static void msm_gpio_irq_mask(struct irq_data *d)

g = &pctrl->soc->groups[d->hwirq];

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

val = readl(pctrl->regs + g->intr_cfg_reg);
val &= ~BIT(g->intr_enable_bit);
@@ -601,7 +601,7 @@ static void msm_gpio_irq_mask(struct irq_data *d)

clear_bit(d->hwirq, pctrl->enabled_irqs);

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

static void msm_gpio_irq_unmask(struct irq_data *d)
@@ -614,7 +614,7 @@ static void msm_gpio_irq_unmask(struct irq_data *d)

g = &pctrl->soc->groups[d->hwirq];

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

val = readl(pctrl->regs + g->intr_status_reg);
val &= ~BIT(g->intr_status_bit);
@@ -626,7 +626,7 @@ static void msm_gpio_irq_unmask(struct irq_data *d)

set_bit(d->hwirq, pctrl->enabled_irqs);

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

static void msm_gpio_irq_ack(struct irq_data *d)
@@ -639,7 +639,7 @@ static void msm_gpio_irq_ack(struct irq_data *d)

g = &pctrl->soc->groups[d->hwirq];

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

val = readl(pctrl->regs + g->intr_status_reg);
if (g->intr_ack_high)
@@ -651,7 +651,7 @@ static void msm_gpio_irq_ack(struct irq_data *d)
if (test_bit(d->hwirq, pctrl->dual_edge_irqs))
msm_gpio_update_dual_edge_pos(pctrl, g, d);

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

static int msm_gpio_irq_set_type(struct irq_data *d, unsigned int type)
@@ -664,7 +664,7 @@ static int msm_gpio_irq_set_type(struct irq_data *d, unsigned int type)

g = &pctrl->soc->groups[d->hwirq];

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

/*
* For hw without possibility of detecting both edges
@@ -738,7 +738,7 @@ static int msm_gpio_irq_set_type(struct irq_data *d, unsigned int type)
if (test_bit(d->hwirq, pctrl->dual_edge_irqs))
msm_gpio_update_dual_edge_pos(pctrl, g, d);

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

if (type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
__irq_set_handler_locked(d->irq, handle_level_irq);
@@ -754,11 +754,11 @@ static int msm_gpio_irq_set_wake(struct irq_data *d, unsigned int on)
struct msm_pinctrl *pctrl = to_msm_pinctrl(gc);
unsigned long flags;

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

irq_set_irq_wake(pctrl->irq, on);

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

return 0;
}
@@ -895,7 +895,7 @@ int msm_pinctrl_probe(struct platform_device *pdev,
pctrl->soc = soc_data;
pctrl->chip = msm_gpio_template;

- spin_lock_init(&pctrl->lock);
+ raw_spin_lock_init(&pctrl->lock);

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
pctrl->regs = devm_ioremap_resource(&pdev->dev, res);
--
2.10.2