On 07/24/2013 01:49 PM, Lee Jones wrote:
On Tue, 23 Jul 2013, Grygorii Strashko wrote:From: Naga Venkata Srikanth V <vnv.srikanth@xxxxxxxxxxx> 1) Removed request_irq() and replaced it with request_threaded_irq(). 2) Removed generic_handle_irq() and replaced it with handle_nested_irq(). Handling of these interrupts is nested, as we are handling an interrupt (for e.g rtc, mmc1) when we are still servicing TWL irq. 3) Removed I2C read-retry logic for the case when twl_i2c_read() is failed inside IRQ handler - there is no sense to do that, so just report an error and return. Signed-off-by: Naga Venkata Srikanth V <vnv.srikanth@xxxxxxxxxxx> Signed-off-by: Oleg_Kosheliev <oleg.kosheliev@xxxxxx> Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx> --- drivers/mfd/twl6030-irq.c | 146 +++++++++++++++------------------------------ 1 file changed, 49 insertions(+), 97 deletions(-)Besides the points I mention below I like the way this patch is going.diff --git a/drivers/mfd/twl6030-irq.c b/drivers/mfd/twl6030-irq.c index 277a8db..b6030d9 100644 --- a/drivers/mfd/twl6030-irq.c +++ b/drivers/mfd/twl6030-irq.c @@ -90,7 +90,6 @@ static unsigned twl6030_irq_base; static int twl_irq; static bool twl_irq_wake_enabled; -static struct completion irq_event; static atomic_t twl6030_wakeirqs = ATOMIC_INIT(0); static int twl6030_irq_pm_notifier(struct notifier_block *notifier, @@ -131,95 +130,57 @@ static struct notifier_block twl6030_irq_pm_notifier_block = { }; /* - * This thread processes interrupts reported by the Primary Interrupt Handler. - */ -static int twl6030_irq_thread(void *data) +* Threaded irq handler for the twl6030 interrupt. +* We query the interrupt controller in the twl6030 to determine +* which module is generating the interrupt request and call +* handle_nested_irq for that module. +*/ +static irqreturn_t twl6030_irq_thread(int irq, void *data) { - long irq = (long)data; - static unsigned i2c_errors; - static const unsigned max_i2c_errors = 100; - int ret; - - while (!kthread_should_stop()) { - int i; - union { + int i, ret; + union { u8 bytes[4]; u32 int_sts; - } sts; - - /* Wait for IRQ, then read PIH irq status (also blocking) */ - wait_for_completion_interruptible(&irq_event); - - /* read INT_STS_A, B and C in one shot using a burst read */ - ret = twl_i2c_read(TWL_MODULE_PIH, sts.bytes, - REG_INT_STS_A, 3); - if (ret) { - pr_warning("twl6030: I2C error %d reading PIH ISR\n", - ret); - if (++i2c_errors >= max_i2c_errors) { - printk(KERN_ERR "Maximum I2C error count" - " exceeded. Terminating %s.\n", - __func__); - break; - } - complete(&irq_event); - continue; - } - + } sts; + /* read INT_STS_A, B and C in one shot using a burst read */ + ret = twl_i2c_read(TWL_MODULE_PIH, sts.bytes, REG_INT_STS_A, 3);
sts.int_sts - is filled here
+ if (ret) { + pr_warn("%s: I2C error %d reading PIH ISR\n", __func__, ret);Does the user really care which function we're returning from. Would it be better if you replace '__func__' with the device name?
This module hasn't been converted to the device yet:( (I mean "interrupt-controller").But I'm thinking about it as the next step :) and then It will be absolutely reasonable change to replace pr_*() with dev_*() and remove __func__.
Now, the pointer on "dev" (in our case "twl-core" device) isn't passed in IRQ handler, so It can't be used here. Of course it can be done, but would it make code better? My opinion - no.
+ return IRQ_HANDLED; + } - sts.bytes[3] = 0; /* Only 24 bits are valid*/ + sts.bytes[3] = 0; /* Only 24 bits are valid*/ - /* - * Since VBUS status bit is not reliable for VBUS disconnect - * use CHARGER VBUS detection status bit instead. - */ - if (sts.bytes[2] & 0x10) - sts.bytes[2] |= 0x08; + /* + * Since VBUS status bit is not reliable for VBUS disconnect + * use CHARGER VBUS detection status bit instead. + */ + if (sts.bytes[2] & 0x10) + sts.bytes[2] |= 0x08; - for (i = 0; sts.int_sts; sts.int_sts >>= 1, i++) { - local_irq_disable(); - if (sts.int_sts & 0x1) { - int module_irq = twl6030_irq_base + + for (i = 0; sts.int_sts; sts.int_sts >>= 1, i++) + if (sts.int_sts & 0x1) {I'm a little confused by this. Where does sts.int_sts come from?
See my comment above, pls
+ int module_irq = twl6030_irq_base + twl6030_interrupt_mapping[i]; - generic_handle_irq(module_irq); - - } - local_irq_enable(); + handle_nested_irq(module_irq); + pr_debug("%s: PIH ISR %u, virq%u\n", + __func__, i, module_irq); } - /* - * NOTE: - * Simulation confirms that documentation is wrong w.r.t the - * interrupt status clear operation. A single *byte* write to - * any one of STS_A to STS_C register results in all three - * STS registers being reset. Since it does not matter which - * value is written, all three registers are cleared on a - * single byte write, so we just use 0x0 to clear. - */ - ret = twl_i2c_write_u8(TWL_MODULE_PIH, 0x00, REG_INT_STS_A); - if (ret) - pr_warning("twl6030: I2C error in clearing PIH ISR\n"); - - enable_irq(irq); - } - - return 0; -} + /* + * NOTE: + * Simulation confirms that documentation is wrong w.r.t the + * interrupt status clear operation. A single *byte* write to + * any one of STS_A to STS_C register results in all three + * STS registers being reset. Since it does not matter which + * value is written, all three registers are cleared on a + * single byte write, so we just use 0x0 to clear. + */ + ret = twl_i2c_write_u8(TWL_MODULE_PIH, 0x00, REG_INT_STS_A); + if (ret) + pr_warn("twl6030: I2C error in clearing PIH ISR\n"); -/* - * handle_twl6030_int() is the desc->handle method for the twl6030 interrupt. - * This is a chained interrupt, so there is no desc->action method for it. - * Now we need to query the interrupt controller in the twl6030 to determine - * which module is generating the interrupt request. However, we can't do i2c - * transactions in interrupt context, so we must defer that work to a kernel - * thread. All we do here is acknowledge and mask the interrupt and wakeup - * the kernel thread. - */ -static irqreturn_t handle_twl6030_pih(int irq, void *devid) -{ - disable_irq_nosync(irq); - complete(devid); return IRQ_HANDLED; } @@ -351,7 +312,6 @@ int twl6030_init_irq(struct device *dev, int irq_num) { struct device_node *node = dev->of_node; int nr_irqs, irq_base, irq_end; - struct task_struct *task; static struct irq_chip twl6030_irq_chip; int status = 0; int i; @@ -396,36 +356,25 @@ int twl6030_init_irq(struct device *dev, int irq_num) irq_set_chip_and_handler(i, &twl6030_irq_chip, handle_simple_irq); irq_set_chip_data(i, (void *)irq_num); + irq_set_nested_thread(i, true); activate_irq(i); } - dev_info(dev, "PIH (irq %d) chaining IRQs %d..%d\n", - irq_num, irq_base, irq_end); + dev_info(dev, "PIH (irq %d) nested IRQs %d..%d\n", + irq_num, irq_base, irq_end); /* install an irq handler to demultiplex the TWL6030 interrupt */ - init_completion(&irq_event); - - status = request_irq(irq_num, handle_twl6030_pih, 0, "TWL6030-PIH", - &irq_event); + status = request_threaded_irq(irq_num, NULL, twl6030_irq_thread, + IRQF_ONESHOT, "TWL6030-PIH", NULL); if (status < 0) { dev_err(dev, "could not claim irq %d: %d\n", irq_num, status); goto fail_irq; } - task = kthread_run(twl6030_irq_thread, (void *)irq_num, "twl6030-irq"); - if (IS_ERR(task)) { - dev_err(dev, "could not create irq %d thread!\n", irq_num); - status = PTR_ERR(task); - goto fail_kthread; - } - twl_irq = irq_num; register_pm_notifier(&twl6030_irq_pm_notifier_block); return irq_base; -fail_kthread: - free_irq(irq_num, &irq_event); - fail_irq: for (i = irq_base; i < irq_end; i++) irq_set_chip_and_handler(i, NULL, NULL); @@ -437,10 +386,13 @@ int twl6030_exit_irq(void) { unregister_pm_notifier(&twl6030_irq_pm_notifier_block); - if (twl6030_irq_base) { + if (!twl6030_irq_base) { pr_err("twl6030: can't yet clean up IRQs?\n"); return -ENOSYS; } + + free_irq(twl_irq, NULL); +If request_threaded_irq() fails, isn't there a chance that twl6030_irq_base will be allocated, but twl_irq will still be undefined?
Yes. A mess is here (historically:), thanks. Will use twl_irq instead of twl6030_irq_base (I did it, actually, in patch [3]:).
return 0; }
Thanks for review. Regards, - grygorii -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
