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powerpc/mpc52xx_gpt: make use of raw_spinlock variants 

The mpc52xx_gpt code 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: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Julia Cartwright 2017-03-21 17:43:03 -05:00 committed by Michael Ellerman
parent f2be629568
commit 77720c8291
1 changed files with 26 additions and 26 deletions
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52
arch/powerpc/platforms/52xx/mpc52xx_gpt.c
View File

@ -90,7 +90,7 @@ struct mpc52xx_gpt_priv {
struct list_head list; /* List of all GPT devices */
struct device *dev;
struct mpc52xx_gpt __iomem *regs;
spinlock_t lock;
raw_spinlock_t lock;
struct irq_domain *irqhost;
u32 ipb_freq;
u8 wdt_mode;
@ -141,9 +141,9 @@ static void mpc52xx_gpt_irq_unmask(struct irq_data *d)
struct mpc52xx_gpt_priv *gpt = irq_data_get_irq_chip_data(d);
unsigned long flags;
spin_lock_irqsave(&gpt->lock, flags);
raw_spin_lock_irqsave(&gpt->lock, flags);
setbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_IRQ_EN);
spin_unlock_irqrestore(&gpt->lock, flags);
raw_spin_unlock_irqrestore(&gpt->lock, flags);
}
static void mpc52xx_gpt_irq_mask(struct irq_data *d)
@ -151,9 +151,9 @@ static void mpc52xx_gpt_irq_mask(struct irq_data *d)
struct mpc52xx_gpt_priv *gpt = irq_data_get_irq_chip_data(d);
unsigned long flags;
spin_lock_irqsave(&gpt->lock, flags);
raw_spin_lock_irqsave(&gpt->lock, flags);
clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_IRQ_EN);
spin_unlock_irqrestore(&gpt->lock, flags);
raw_spin_unlock_irqrestore(&gpt->lock, flags);
}
static void mpc52xx_gpt_irq_ack(struct irq_data *d)
@ -171,14 +171,14 @@ static int mpc52xx_gpt_irq_set_type(struct irq_data *d, unsigned int flow_type)
dev_dbg(gpt->dev, "%s: virq=%i type=%x\n", __func__, d->irq, flow_type);
spin_lock_irqsave(&gpt->lock, flags);
raw_spin_lock_irqsave(&gpt->lock, flags);
reg = in_be32(&gpt->regs->mode) & ~MPC52xx_GPT_MODE_ICT_MASK;
if (flow_type & IRQF_TRIGGER_RISING)
reg |= MPC52xx_GPT_MODE_ICT_RISING;
if (flow_type & IRQF_TRIGGER_FALLING)
reg |= MPC52xx_GPT_MODE_ICT_FALLING;
out_be32(&gpt->regs->mode, reg);
spin_unlock_irqrestore(&gpt->lock, flags);
raw_spin_unlock_irqrestore(&gpt->lock, flags);
return 0;
}
@ -264,11 +264,11 @@ mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node)
/* If the GPT is currently disabled, then change it to be in Input
* Capture mode. If the mode is non-zero, then the pin could be
* already in use for something. */
spin_lock_irqsave(&gpt->lock, flags);
raw_spin_lock_irqsave(&gpt->lock, flags);
mode = in_be32(&gpt->regs->mode);
if ((mode & MPC52xx_GPT_MODE_MS_MASK) == 0)
out_be32(&gpt->regs->mode, mode | MPC52xx_GPT_MODE_MS_IC);
spin_unlock_irqrestore(&gpt->lock, flags);
raw_spin_unlock_irqrestore(&gpt->lock, flags);
dev_dbg(gpt->dev, "%s() complete. virq=%i\n", __func__, cascade_virq);
}
@ -295,9 +295,9 @@ mpc52xx_gpt_gpio_set(struct gpio_chip *gc, unsigned int gpio, int v)
dev_dbg(gpt->dev, "%s: gpio:%d v:%d\n", __func__, gpio, v);
r = v ? MPC52xx_GPT_MODE_GPIO_OUT_HIGH : MPC52xx_GPT_MODE_GPIO_OUT_LOW;
spin_lock_irqsave(&gpt->lock, flags);
raw_spin_lock_irqsave(&gpt->lock, flags);
clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_GPIO_MASK, r);
spin_unlock_irqrestore(&gpt->lock, flags);
raw_spin_unlock_irqrestore(&gpt->lock, flags);
}
static int mpc52xx_gpt_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
@ -307,9 +307,9 @@ static int mpc52xx_gpt_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
dev_dbg(gpt->dev, "%s: gpio:%d\n", __func__, gpio);
spin_lock_irqsave(&gpt->lock, flags);
raw_spin_lock_irqsave(&gpt->lock, flags);
clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_GPIO_MASK);
spin_unlock_irqrestore(&gpt->lock, flags);
raw_spin_unlock_irqrestore(&gpt->lock, flags);
return 0;
}
@ -436,16 +436,16 @@ static int mpc52xx_gpt_do_start(struct mpc52xx_gpt_priv *gpt, u64 period,
}
/* Set and enable the timer, reject an attempt to use a wdt as gpt */
spin_lock_irqsave(&gpt->lock, flags);
raw_spin_lock_irqsave(&gpt->lock, flags);
if (as_wdt)
gpt->wdt_mode |= MPC52xx_GPT_IS_WDT;
else if ((gpt->wdt_mode & MPC52xx_GPT_IS_WDT) != 0) {
spin_unlock_irqrestore(&gpt->lock, flags);
raw_spin_unlock_irqrestore(&gpt->lock, flags);
return -EBUSY;
}
out_be32(&gpt->regs->count, prescale << 16 | clocks);
clrsetbits_be32(&gpt->regs->mode, clear, set);
spin_unlock_irqrestore(&gpt->lock, flags);
raw_spin_unlock_irqrestore(&gpt->lock, flags);
return 0;
}
@ -476,14 +476,14 @@ int mpc52xx_gpt_stop_timer(struct mpc52xx_gpt_priv *gpt)
unsigned long flags;
/* reject the operation if the timer is used as watchdog (gpt 0 only) */
spin_lock_irqsave(&gpt->lock, flags);
raw_spin_lock_irqsave(&gpt->lock, flags);
if ((gpt->wdt_mode & MPC52xx_GPT_IS_WDT) != 0) {
spin_unlock_irqrestore(&gpt->lock, flags);
raw_spin_unlock_irqrestore(&gpt->lock, flags);
return -EBUSY;
}
clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_COUNTER_ENABLE);
spin_unlock_irqrestore(&gpt->lock, flags);
raw_spin_unlock_irqrestore(&gpt->lock, flags);
return 0;
}
EXPORT_SYMBOL(mpc52xx_gpt_stop_timer);
@ -500,9 +500,9 @@ u64 mpc52xx_gpt_timer_period(struct mpc52xx_gpt_priv *gpt)
u64 prescale;
unsigned long flags;
spin_lock_irqsave(&gpt->lock, flags);
raw_spin_lock_irqsave(&gpt->lock, flags);
period = in_be32(&gpt->regs->count);
spin_unlock_irqrestore(&gpt->lock, flags);
raw_spin_unlock_irqrestore(&gpt->lock, flags);
prescale = period >> 16;
period &= 0xffff;
@ -532,9 +532,9 @@ static inline void mpc52xx_gpt_wdt_ping(struct mpc52xx_gpt_priv *gpt_wdt)
{
unsigned long flags;
spin_lock_irqsave(&gpt_wdt->lock, flags);
raw_spin_lock_irqsave(&gpt_wdt->lock, flags);
out_8((u8 *) &gpt_wdt->regs->mode, MPC52xx_GPT_MODE_WDT_PING);
spin_unlock_irqrestore(&gpt_wdt->lock, flags);
raw_spin_unlock_irqrestore(&gpt_wdt->lock, flags);
}
/* wdt misc device api */
@ -638,11 +638,11 @@ static int mpc52xx_wdt_release(struct inode *inode, struct file *file)
struct mpc52xx_gpt_priv *gpt_wdt = file->private_data;
unsigned long flags;
spin_lock_irqsave(&gpt_wdt->lock, flags);
raw_spin_lock_irqsave(&gpt_wdt->lock, flags);
clrbits32(&gpt_wdt->regs->mode,
MPC52xx_GPT_MODE_COUNTER_ENABLE | MPC52xx_GPT_MODE_WDT_EN);
gpt_wdt->wdt_mode &= ~MPC52xx_GPT_IS_WDT;
spin_unlock_irqrestore(&gpt_wdt->lock, flags);
raw_spin_unlock_irqrestore(&gpt_wdt->lock, flags);
#endif
clear_bit(0, &wdt_is_active);
return 0;
@ -723,7 +723,7 @@ static int mpc52xx_gpt_probe(struct platform_device *ofdev)
if (!gpt)
return -ENOMEM;
spin_lock_init(&gpt->lock);
raw_spin_lock_init(&gpt->lock);
gpt->dev = &ofdev->dev;
gpt->ipb_freq = mpc5xxx_get_bus_frequency(ofdev->dev.of_node);
gpt->regs = of_iomap(ofdev->dev.of_node, 0);