[PATCH v2 4/9] mfd: asic3: make use of raw_spinlock variants

Julia Cartwright
2017-03-21T22:43:04Z

The asic3 mfd 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.

Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Julia Cartwright <julia@ni.com>
---
v1 -> v2:
- No functional change. Added Lee's ack.

drivers/mfd/asic3.c | 56 ++++++++++++++++++++++++++---------------------------
1 file changed, 28 insertions(+), 28 deletions(-)

diff --git a/drivers/mfd/asic3.c b/drivers/mfd/asic3.c
index 0413c8159551..cf2e25ab2940 100644
--- a/drivers/mfd/asic3.c
+++ b/drivers/mfd/asic3.c
@@ -78,7 +78,7 @@ struct asic3 {
unsigned int bus_shift;
unsigned int irq_nr;
unsigned int irq_base;
- spinlock_t lock;
+ raw_spinlock_t lock;
u16 irq_bothedge[4];
struct gpio_chip gpio;
struct device *dev;
@@ -108,14 +108,14 @@ static void asic3_set_register(struct asic3 *asic, u32 reg, u32 bits, bool set)
unsigned long flags;
u32 val;

- spin_lock_irqsave(&asic->lock, flags);
+ raw_spin_lock_irqsave(&asic->lock, flags);
val = asic3_read_register(asic, reg);
if (set)
val |= bits;
else
val &= ~bits;
asic3_write_register(asic, reg, val);
- spin_unlock_irqrestore(&asic->lock, flags);
+ raw_spin_unlock_irqrestore(&asic->lock, flags);
}

/* IRQs */
@@ -129,13 +129,13 @@ static void asic3_irq_flip_edge(struct asic3 *asic,
u16 edge;
unsigned long flags;

- spin_lock_irqsave(&asic->lock, flags);
+ raw_spin_lock_irqsave(&asic->lock, flags);
edge = asic3_read_register(asic,
base + ASIC3_GPIO_EDGE_TRIGGER);
edge ^= bit;
asic3_write_register(asic,
base + ASIC3_GPIO_EDGE_TRIGGER, edge);
- spin_unlock_irqrestore(&asic->lock, flags);
+ raw_spin_unlock_irqrestore(&asic->lock, flags);
}

static void asic3_irq_demux(struct irq_desc *desc)
@@ -151,10 +151,10 @@ static void asic3_irq_demux(struct irq_desc *desc)
u32 status;
int bank;

- spin_lock_irqsave(&asic->lock, flags);
+ raw_spin_lock_irqsave(&asic->lock, flags);
status = asic3_read_register(asic,
ASIC3_OFFSET(INTR, P_INT_STAT));
- spin_unlock_irqrestore(&asic->lock, flags);
+ raw_spin_unlock_irqrestore(&asic->lock, flags);

/* Check all ten register bits */
if ((status & 0x3ff) == 0)
@@ -167,7 +167,7 @@ static void asic3_irq_demux(struct irq_desc *desc)

base = ASIC3_GPIO_A_BASE
+ bank * ASIC3_GPIO_BASE_INCR;
- spin_lock_irqsave(&asic->lock, flags);
+ raw_spin_lock_irqsave(&asic->lock, flags);
istat = asic3_read_register(asic,
base +
ASIC3_GPIO_INT_STATUS);
@@ -175,7 +175,7 @@ static void asic3_irq_demux(struct irq_desc *desc)
asic3_write_register(asic,
base +
ASIC3_GPIO_INT_STATUS, 0);
- spin_unlock_irqrestore(&asic->lock, flags);
+ raw_spin_unlock_irqrestore(&asic->lock, flags);

for (i = 0; i < ASIC3_GPIOS_PER_BANK; i++) {
int bit = (1 << i);
@@ -230,11 +230,11 @@ static void asic3_mask_gpio_irq(struct irq_data *data)
bank = asic3_irq_to_bank(asic, data->irq);
index = asic3_irq_to_index(asic, data->irq);

- spin_lock_irqsave(&asic->lock, flags);
+ raw_spin_lock_irqsave(&asic->lock, flags);
val = asic3_read_register(asic, bank + ASIC3_GPIO_MASK);
val |= 1 << index;
asic3_write_register(asic, bank + ASIC3_GPIO_MASK, val);
- spin_unlock_irqrestore(&asic->lock, flags);
+ raw_spin_unlock_irqrestore(&asic->lock, flags);
}

static void asic3_mask_irq(struct irq_data *data)
@@ -243,7 +243,7 @@ static void asic3_mask_irq(struct irq_data *data)
int regval;
unsigned long flags;

- spin_lock_irqsave(&asic->lock, flags);
+ raw_spin_lock_irqsave(&asic->lock, flags);
regval = asic3_read_register(asic,
ASIC3_INTR_BASE +
ASIC3_INTR_INT_MASK);
@@ -255,7 +255,7 @@ static void asic3_mask_irq(struct irq_data *data)
ASIC3_INTR_BASE +
ASIC3_INTR_INT_MASK,
regval);
- spin_unlock_irqrestore(&asic->lock, flags);
+ raw_spin_unlock_irqrestore(&asic->lock, flags);
}

static void asic3_unmask_gpio_irq(struct irq_data *data)
@@ -267,11 +267,11 @@ static void asic3_unmask_gpio_irq(struct irq_data *data)
bank = asic3_irq_to_bank(asic, data->irq);
index = asic3_irq_to_index(asic, data->irq);

- spin_lock_irqsave(&asic->lock, flags);
+ raw_spin_lock_irqsave(&asic->lock, flags);
val = asic3_read_register(asic, bank + ASIC3_GPIO_MASK);
val &= ~(1 << index);
asic3_write_register(asic, bank + ASIC3_GPIO_MASK, val);
- spin_unlock_irqrestore(&asic->lock, flags);
+ raw_spin_unlock_irqrestore(&asic->lock, flags);
}

static void asic3_unmask_irq(struct irq_data *data)
@@ -280,7 +280,7 @@ static void asic3_unmask_irq(struct irq_data *data)
int regval;
unsigned long flags;

- spin_lock_irqsave(&asic->lock, flags);
+ raw_spin_lock_irqsave(&asic->lock, flags);
regval = asic3_read_register(asic,
ASIC3_INTR_BASE +
ASIC3_INTR_INT_MASK);
@@ -292,7 +292,7 @@ static void asic3_unmask_irq(struct irq_data *data)
ASIC3_INTR_BASE +
ASIC3_INTR_INT_MASK,
regval);
- spin_unlock_irqrestore(&asic->lock, flags);
+ raw_spin_unlock_irqrestore(&asic->lock, flags);
}

static int asic3_gpio_irq_type(struct irq_data *data, unsigned int type)
@@ -306,7 +306,7 @@ static int asic3_gpio_irq_type(struct irq_data *data, unsigned int type)
index = asic3_irq_to_index(asic, data->irq);
bit = 1<<index;

- spin_lock_irqsave(&asic->lock, flags);
+ raw_spin_lock_irqsave(&asic->lock, flags);
level = asic3_read_register(asic,
bank + ASIC3_GPIO_LEVEL_TRIGGER);
edge = asic3_read_register(asic,
@@ -348,7 +348,7 @@ static int asic3_gpio_irq_type(struct irq_data *data, unsigned int type)
edge);
asic3_write_register(asic, bank + ASIC3_GPIO_TRIGGER_TYPE,
trigger);
- spin_unlock_irqrestore(&asic->lock, flags);
+ raw_spin_unlock_irqrestore(&asic->lock, flags);
return 0;
}

@@ -455,7 +455,7 @@ static int asic3_gpio_direction(struct gpio_chip *chip,
return -EINVAL;
}

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

out_reg = asic3_read_register(asic, gpio_base + ASIC3_GPIO_DIRECTION);

@@ -467,7 +467,7 @@ static int asic3_gpio_direction(struct gpio_chip *chip,

asic3_write_register(asic, gpio_base + ASIC3_GPIO_DIRECTION, out_reg);

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

return 0;

@@ -524,7 +524,7 @@ static void asic3_gpio_set(struct gpio_chip *chip,

mask = ASIC3_GPIO_TO_MASK(offset);

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

out_reg = asic3_read_register(asic, gpio_base + ASIC3_GPIO_OUT);

@@ -535,7 +535,7 @@ static void asic3_gpio_set(struct gpio_chip *chip,

asic3_write_register(asic, gpio_base + ASIC3_GPIO_OUT, out_reg);

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

static int asic3_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
@@ -611,13 +611,13 @@ static void asic3_clk_enable(struct asic3 *asic, struct asic3_clk *clk)
unsigned long flags;
u32 cdex;

- spin_lock_irqsave(&asic->lock, flags);
+ raw_spin_lock_irqsave(&asic->lock, flags);
if (clk->enabled++ == 0) {
cdex = asic3_read_register(asic, ASIC3_OFFSET(CLOCK, CDEX));
cdex |= clk->cdex;
asic3_write_register(asic, ASIC3_OFFSET(CLOCK, CDEX), cdex);
}
- spin_unlock_irqrestore(&asic->lock, flags);
+ raw_spin_unlock_irqrestore(&asic->lock, flags);
}

static void asic3_clk_disable(struct asic3 *asic, struct asic3_clk *clk)
@@ -627,13 +627,13 @@ static void asic3_clk_disable(struct asic3 *asic, struct asic3_clk *clk)

WARN_ON(clk->enabled == 0);

- spin_lock_irqsave(&asic->lock, flags);
+ raw_spin_lock_irqsave(&asic->lock, flags);
if (--clk->enabled == 0) {
cdex = asic3_read_register(asic, ASIC3_OFFSET(CLOCK, CDEX));
cdex &= ~clk->cdex;
asic3_write_register(asic, ASIC3_OFFSET(CLOCK, CDEX), cdex);
}
- spin_unlock_irqrestore(&asic->lock, flags);
+ raw_spin_unlock_irqrestore(&asic->lock, flags);
}

/* MFD cells (SPI, PWM, LED, DS1WM, MMC) */
@@ -963,7 +963,7 @@ static int __init asic3_probe(struct platform_device *pdev)
if (!asic)
return -ENOMEM;

- spin_lock_init(&asic->lock);
+ raw_spin_lock_init(&asic->lock);
platform_set_drvdata(pdev, asic);
asic->dev = &pdev->dev;

--
2.12.0