*/
#include <linux/module.h>
-#include <linux/kernel_stat.h>
#include <linux/init.h>
-#include <linux/time.h>
#include <linux/interrupt.h>
-#include <linux/device.h>
#include <linux/kthread.h>
#include <linux/irq.h>
#include <linux/gpio.h>
/* store usage of each GPIO. - each bit represents one GPIO */
static unsigned int gpio_usage_count;
-/* shadow the imr register */
-static unsigned int gpio_imr_shadow;
+/* protect what irq_chip modifies through its helper task */
+static DEFINE_SPINLOCK(gpio_spinlock);
-/* bitmask of pending requests to unmask gpio interrupts */
-static unsigned int gpio_pending_unmask;
+/* shadow the imr register; updates are delayed */
+static u32 gpio_imr_shadow;
+static bool gpio_pending_mask;
/* bitmask of requests to set gpio irq trigger type */
static unsigned int gpio_pending_trigger;
-/* pointer to gpio unmask thread struct */
-static struct task_struct *gpio_unmask_thread;
+/* pointer to helper thread */
+static struct task_struct *gpio_helper_thread;
/*
* Helper functions to read and write the GPIO ISR and IMR registers as
* The caller must hold gpio_lock.
*/
+/* NOTE: only the IRQ dispatcher may read ISR; reading it has
+ * side effects, because of the clear-on-read mechanism (COR=1).
+ */
static int gpio_read_isr(unsigned int *isr)
{
int ret;
return ret;
}
-static int gpio_write_isr(unsigned int isr)
-{
- isr &= GPIO_32_MASK;
- /*
- * The buffer passed to the twl4030_i2c_write() routine must have an
- * extra byte at the beginning reserved for its internal use.
- */
- isr <<= 8;
- isr = cpu_to_le32(isr);
- return twl4030_i2c_write(TWL4030_MODULE_GPIO, (u8 *) &isr,
- REG_GPIO_ISR1A, 3);
-}
-
+/* IMR is written only during initialization and
+ * by request of the irq_chip code.
+ */
static int gpio_write_imr(unsigned int imr)
{
imr &= GPIO_32_MASK;
REG_GPIO_IMR1A, 3);
}
-/*
- * These routines are analagous to the irqchip methods, but they are designed
- * to be called from thread context with cpu interrupts enabled and with no
- * locked spinlocks. We call these routines from our custom IRQ handler
- * instead of the usual irqchip methods.
- */
-static void twl4030_gpio_mask_and_ack(unsigned int irq)
-{
- int gpio = irq - twl4030_gpio_irq_base;
-
- mutex_lock(&gpio_lock);
- /* mask */
- gpio_imr_shadow |= (1 << gpio);
- gpio_write_imr(gpio_imr_shadow);
- /* ack */
- gpio_write_isr(1 << gpio);
- mutex_unlock(&gpio_lock);
-}
-
-static void twl4030_gpio_unmask(unsigned int irq)
-{
- int gpio = irq - twl4030_gpio_irq_base;
-
- mutex_lock(&gpio_lock);
- gpio_imr_shadow &= ~(1 << gpio);
- gpio_write_imr(gpio_imr_shadow);
- mutex_unlock(&gpio_lock);
-}
-
/*
* These are the irqchip methods for the TWL4030 GPIO interrupts.
* Our IRQ handle method doesn't call these, but they will be called by
* other routines such as setup_irq() and enable_irq(). They are called
- * with cpu interrupts disabled and with a lock on the irq_controller_lock
+ * with cpu interrupts disabled and with a lock on the irq_desc.lock
* spinlock. This complicates matters, because accessing the TWL4030 GPIO
* interrupt controller requires I2C bus transactions that can't be initiated
* in this context. Our solution is to defer accessing the interrupt
- * controller to a kernel thread. We only need to support the unmask method.
+ * controller to a kernel thread.
*/
-static void twl4030_gpio_irq_mask_and_ack(unsigned int irq)
+static void twl4030_gpio_irq_ack(unsigned int irq)
{
+ /* NOP -- dispatcher acks when it reads ISR */
}
static void twl4030_gpio_irq_mask(unsigned int irq)
{
+ int gpio = irq - twl4030_gpio_irq_base;
+ u32 mask = 1 << gpio;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gpio_spinlock, flags);
+ gpio_pending_mask = true;
+ gpio_imr_shadow |= mask;
+ if (gpio_helper_thread && gpio_helper_thread->state != TASK_RUNNING)
+ wake_up_process(gpio_helper_thread);
+ spin_unlock_irqrestore(&gpio_spinlock, flags);
}
static void twl4030_gpio_irq_unmask(unsigned int irq)
{
int gpio = irq - twl4030_gpio_irq_base;
+ u32 mask = 1 << gpio;
+ unsigned long flags;
- gpio_pending_unmask |= (1 << gpio);
- if (gpio_unmask_thread && gpio_unmask_thread->state != TASK_RUNNING)
- wake_up_process(gpio_unmask_thread);
+ spin_lock_irqsave(&gpio_spinlock, flags);
+ gpio_pending_mask = true;
+ gpio_imr_shadow &= ~mask;
+ if (gpio_helper_thread && gpio_helper_thread->state != TASK_RUNNING)
+ wake_up_process(gpio_helper_thread);
+ spin_unlock_irqrestore(&gpio_spinlock, flags);
}
static int twl4030_gpio_irq_set_type(unsigned int irq, unsigned trigger)
{
struct irq_desc *desc = irq_desc + irq;
int gpio = irq - twl4030_gpio_irq_base;
+ unsigned long flags;
trigger &= IRQ_TYPE_SENSE_MASK;
if (trigger & ~IRQ_TYPE_EDGE_BOTH)
desc->status &= ~IRQ_TYPE_SENSE_MASK;
desc->status |= trigger;
- /* REVISIT This makes the "unmask" thread do double duty,
- * updating IRQ trigger modes too. Rename appropriately...
- */
+ spin_lock_irqsave(&gpio_spinlock, flags);
gpio_pending_trigger |= (1 << gpio);
- if (gpio_unmask_thread && gpio_unmask_thread->state != TASK_RUNNING)
- wake_up_process(gpio_unmask_thread);
+ if (gpio_helper_thread && gpio_helper_thread->state != TASK_RUNNING)
+ wake_up_process(gpio_helper_thread);
+ spin_unlock_irqrestore(&gpio_spinlock, flags);
return 0;
}
static struct irq_chip twl4030_gpio_irq_chip = {
.name = "twl4030",
- .ack = twl4030_gpio_irq_mask_and_ack,
+ .ack = twl4030_gpio_irq_ack,
.mask = twl4030_gpio_irq_mask,
.unmask = twl4030_gpio_irq_unmask,
.set_type = twl4030_gpio_irq_set_type,
if (!gpio_usage_count) {
ret = gpio_twl4030_write(REG_GPIO_CTRL,
MASK_GPIO_CTRL_GPIO_ON);
- ret = gpio_twl4030_write(REG_GPIO_SIH_CTRL, 0x00);
+
}
if (!ret)
gpio_usage_count |= BIT(gpio);
/* MODULE FUNCTIONS */
/*
- * gpio_unmask_thread() runs as a kernel thread. It is awakened by the unmask
- * method for the GPIO interrupts. It unmasks all of the GPIO interrupts
- * specified in the gpio_pending_unmask bitmask. We have to do the unmasking
- * in a kernel thread rather than directly in the unmask method because of the
+ * gpio_helper_thread() is a kernel thread that is awakened by irq_chip
+ * methods to update IRQ masks and trigger modes.
+ *
+ * We must do this in a thread rather than in irq_chip methods because of the
* need to access the TWL4030 via the I2C bus. Note that we don't need to be
* concerned about race conditions where the request to unmask a GPIO interrupt
* has already been cancelled before this thread does the unmasking. If a GPIO
* interrupt is improperly unmasked, then the IRQ handler for it will mask it
* when an interrupt occurs.
*/
-static int twl4030_gpio_unmask_thread(void *data)
+static int twl4030_gpio_helper_thread(void *dev)
{
current->flags |= PF_NOFREEZE;
while (!kthread_should_stop()) {
int irq;
- unsigned int gpio_unmask;
+ bool do_mask;
+ u32 local_imr;
unsigned int gpio_trigger;
- local_irq_disable();
- gpio_unmask = gpio_pending_unmask;
- gpio_pending_unmask = 0;
+ spin_lock_irq(&gpio_spinlock);
+
+ do_mask = gpio_pending_mask;
+ gpio_pending_mask = false;
+ local_imr = gpio_imr_shadow;
gpio_trigger = gpio_pending_trigger;
gpio_pending_trigger = 0;
- local_irq_enable();
- for (irq = twl4030_gpio_irq_base; 0 != gpio_unmask;
- gpio_unmask >>= 1, irq++) {
- if (gpio_unmask & 0x1)
- twl4030_gpio_unmask(irq);
+ spin_unlock_irq(&gpio_spinlock);
+
+ if (do_mask) {
+ int status = gpio_write_imr(local_imr);
+
+ if (status)
+ dev_err(dev, "write IMR err %d\n", status);
}
for (irq = twl4030_gpio_irq_base;
type);
}
- local_irq_disable();
- if (!gpio_pending_unmask && !gpio_pending_trigger)
+ spin_lock_irq(&gpio_spinlock);
+ if (!gpio_pending_mask && !gpio_pending_trigger)
set_current_state(TASK_INTERRUPTIBLE);
- local_irq_enable();
+ spin_unlock_irq(&gpio_spinlock);
schedule();
}
return 0;
}
-/*
- * do_twl4030_gpio_irq() is the desc->handle method for each of the twl4030
- * gpio interrupts. It executes in kernel thread context.
- * On entry, cpu interrupts are enabled.
- */
-static void do_twl4030_gpio_irq(unsigned int irq, irq_desc_t *desc)
-{
- struct irqaction *action;
- const unsigned int cpu = smp_processor_id();
-
- desc->status |= IRQ_LEVEL;
-
- /*
- * Acknowledge, clear _AND_ disable the interrupt.
- */
- twl4030_gpio_mask_and_ack(irq);
-
- if (!desc->depth) {
- kstat_cpu(cpu).irqs[irq]++;
-
- action = desc->action;
- if (action) {
- int ret;
- int status = 0;
- int retval = 0;
- do {
- /* Call the ISR with cpu interrupts enabled. */
- ret = action->handler(irq, action->dev_id);
- if (ret == IRQ_HANDLED)
- status |= action->flags;
- retval |= ret;
- action = action->next;
- } while (action);
-
- if (retval != IRQ_HANDLED)
- printk(KERN_ERR "ISR for TWL4030 GPIO"
- " irq %d can't handle interrupt\n",
- irq);
-
- if (!desc->depth)
- twl4030_gpio_unmask(irq);
- }
- }
-}
-
/*
* do_twl4030_gpio_module_irq() is the desc->handle method for the twl4030 gpio
* module interrupt. It executes in kernel thread context.
*/
static void do_twl4030_gpio_module_irq(unsigned int irq, irq_desc_t *desc)
{
- const unsigned int cpu = smp_processor_id();
+ int gpio_irq;
+ unsigned int gpio_isr;
- desc->status |= IRQ_LEVEL;
- /*
- * The desc->handle method would normally call the desc->chip->ack
- * method here, but we won't bother since our ack method is NULL.
- */
- if (!desc->depth) {
- int gpio_irq;
- unsigned int gpio_isr;
-
- kstat_cpu(cpu).irqs[irq]++;
- local_irq_enable();
-
- mutex_lock(&gpio_lock);
- if (gpio_read_isr(&gpio_isr))
- gpio_isr = 0;
- mutex_unlock(&gpio_lock);
-
- for (gpio_irq = twl4030_gpio_irq_base; 0 != gpio_isr;
- gpio_isr >>= 1, gpio_irq++) {
- if (gpio_isr & 0x1) {
- irq_desc_t *d = irq_desc + gpio_irq;
- d->handle_irq(gpio_irq, d);
- }
- }
-
- local_irq_disable();
- /*
- * Here is where we should call the unmask method, but again we
- * won't bother since it is NULL.
- */
+ /* PIH irqs like this can't be individually masked or acked ...
+ * so we don't even call the PIH irq_chip stub methods.
+ */
+ local_irq_enable();
+ if (gpio_read_isr(&gpio_isr))
+ gpio_isr = 0;
+ local_irq_disable();
+
+ for (gpio_irq = twl4030_gpio_irq_base; 0 != gpio_isr;
+ gpio_isr >>= 1, gpio_irq++) {
+ if (gpio_isr & 0x1)
+ generic_handle_irq(gpio_irq);
}
}
int irq = 0;
/* All GPIO interrupts are initially masked */
- gpio_pending_unmask = 0;
+ gpio_pending_mask = false;
gpio_imr_shadow = GPIO_32_MASK;
ret = gpio_write_imr(gpio_imr_shadow);
if (!ret) {
/*
- * Create a kernel thread to handle deferred unmasking of gpio
+ * Create a kernel thread to handle deferred operations on gpio
* interrupts.
*/
- gpio_unmask_thread = kthread_create(twl4030_gpio_unmask_thread,
- NULL, "twl4030 gpio");
- if (!gpio_unmask_thread) {
+ gpio_helper_thread = kthread_create(twl4030_gpio_helper_thread,
+ &pdev->dev, "twl4030 gpio");
+ if (!gpio_helper_thread) {
dev_err(&pdev->dev,
- "could not create twl4030 gpio unmask"
- " thread!\n");
+ "could not create helper thread!\n");
ret = -ENOMEM;
}
}
for (irq = twl4030_gpio_irq_base; irq < twl4030_gpio_irq_end;
irq++) {
set_irq_chip_and_handler(irq, &twl4030_gpio_irq_chip,
- do_twl4030_gpio_irq);
+ handle_edge_irq);
activate_irq(irq);
}
/* gpio module IRQ */
irq = platform_get_irq(pdev, 0);
+ /* COR=1 means irqs are acked by reading ISR
+ * PENDDIS=0 means pending events enabled
+ * EXCLEN=0 means route to both irq lines
+ */
+ gpio_twl4030_write(REG_GPIO_SIH_CTRL,
+ TWL4030_SIH_CTRL_COR_MASK);
+
/*
* Install an irq handler to demultiplex the gpio module
* interrupt.
*/
set_irq_chained_handler(irq, do_twl4030_gpio_module_irq);
- wake_up_process(gpio_unmask_thread);
+ wake_up_process(gpio_helper_thread);
dev_info(&pdev->dev, "IRQ %d chains IRQs %d..%d\n", irq,
twl4030_gpio_irq_base, twl4030_gpio_irq_end - 1);
for (irq = twl4030_gpio_irq_base; irq < twl4030_gpio_irq_end; irq++)
set_irq_handler(irq, NULL);
- /* stop the gpio unmask kernel thread */
- if (gpio_unmask_thread) {
- kthread_stop(gpio_unmask_thread);
- gpio_unmask_thread = NULL;
+ /* stop the gpio helper kernel thread */
+ if (gpio_helper_thread) {
+ kthread_stop(gpio_helper_thread);
+ gpio_helper_thread = NULL;
}
return 0;
projects / linux-2.6-omap-h63xx.git / commitdiff