From 4b8ac08256781c59b20bfd86fddcf5d620833752 Mon Sep 17 00:00:00 2001 From: Lee Jones Date: Mon, 14 Jan 2013 16:10:36 +0000 Subject: [PATCH] mfd: ab8500-debugfs: Provide a means for a user subscribe to IRQs Allow users to subscribe to and view IRQ events live from debugfs. Signed-off-by: Lee Jones --- drivers/mfd/ab8500-debugfs.c | 198 +++++++++++++++++++++++++++++++++++ 1 file changed, 198 insertions(+) diff --git a/drivers/mfd/ab8500-debugfs.c b/drivers/mfd/ab8500-debugfs.c index 5a8e707bc038..2e40e12fc687 100644 --- a/drivers/mfd/ab8500-debugfs.c +++ b/drivers/mfd/ab8500-debugfs.c @@ -11,6 +11,9 @@ #include #include #include +#include +#include +#include #include #include @@ -18,6 +21,9 @@ static u32 debug_bank; static u32 debug_address; +static int irq_first; +static int irq_last; + /** * struct ab8500_reg_range * @first: the first address of the range @@ -354,6 +360,21 @@ static struct ab8500_prcmu_ranges debug_ranges[AB8500_NUM_BANKS] = { }, }; +static irqreturn_t ab8500_debug_handler(int irq, void *data) +{ + char buf[16]; + struct kobject *kobj = (struct kobject *)data; + + /* + * This makes it possible to use poll for events (POLLPRI | POLLERR) + * from userspace on sysfs file named irq- + */ + sprintf(buf, "irq-%d", irq); + sysfs_notify(kobj, NULL, buf); + + return IRQ_HANDLED; +} + static int ab8500_registers_print(struct seq_file *s, void *p) { struct device *dev = s->private; @@ -519,6 +540,131 @@ static ssize_t ab8500_val_write(struct file *file, return count; } +static int ab8500_subscribe_unsubscribe_print(struct seq_file *s, void *p) +{ + seq_printf(s, "%d\n", irq_first); + + return 0; +} + +static int ab8500_subscribe_unsubscribe_open(struct inode *inode, + struct file *file) +{ + return single_open(file, ab8500_subscribe_unsubscribe_print, + inode->i_private); +} + +/* + * This function is used for all interrupts and will always print + * the same string. It is however this file sysfs_notify called on. + * Userspace should read this file and then poll. When an event occur + * the blocking poll will be released. + */ +static ssize_t show_irq(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "irq\n"); +} + +static struct device_attribute *dev_attr[AB8500_NR_IRQS]; +static char *event_name[AB8500_NR_IRQS]; + +static ssize_t ab8500_subscribe_write(struct file *file, + const char __user *user_buf, + size_t count, loff_t *ppos) +{ + struct device *dev = ((struct seq_file *)(file->private_data))->private; + char buf[32]; + int buf_size; + unsigned long user_val; + int err; + + /* Get userspace string and assure termination */ + buf_size = min(count, (sizeof(buf)-1)); + if (copy_from_user(buf, user_buf, buf_size)) + return -EFAULT; + buf[buf_size] = 0; + + err = strict_strtoul(buf, 0, &user_val); + if (err) + return -EINVAL; + if (user_val < irq_first) { + dev_err(dev, "debugfs error input < %d\n", irq_first); + return -EINVAL; + } + if (user_val > irq_last) { + dev_err(dev, "debugfs error input > %d\n", irq_last); + return -EINVAL; + } + + /* + * This will create a sysfs file named irq- which userspace can + * use to select or poll and get the AB8500 events + */ + dev_attr[user_val] = kmalloc(sizeof(struct device_attribute), + GFP_KERNEL); + event_name[user_val] = kmalloc(buf_size, GFP_KERNEL); + sprintf(event_name[user_val], "irq-%lu", user_val); + dev_attr[user_val]->show = show_irq; + dev_attr[user_val]->store = NULL; + dev_attr[user_val]->attr.name = event_name[user_val]; + dev_attr[user_val]->attr.mode = S_IRUGO; + err = sysfs_create_file(&dev->kobj, &dev_attr[user_val]->attr); + if (err < 0) { + printk(KERN_ERR "sysfs_create_file failed %d\n", err); + return err; + } + + err = request_threaded_irq(user_val, NULL, ab8500_debug_handler, + IRQF_SHARED | IRQF_NO_SUSPEND, + "ab8500-debug", &dev->kobj); + if (err < 0) { + printk(KERN_ERR "request_threaded_irq failed %d, %lu\n", + err, user_val); + return err; + } + + return buf_size; +} + +static ssize_t ab8500_unsubscribe_write(struct file *file, + const char __user *user_buf, + size_t count, loff_t *ppos) +{ + struct device *dev = ((struct seq_file *)(file->private_data))->private; + char buf[32]; + int buf_size; + unsigned long user_val; + int err; + + /* Get userspace string and assure termination */ + buf_size = min(count, (sizeof(buf)-1)); + if (copy_from_user(buf, user_buf, buf_size)) + return -EFAULT; + buf[buf_size] = 0; + + err = strict_strtoul(buf, 0, &user_val); + if (err) + return -EINVAL; + if (user_val < irq_first) { + dev_err(dev, "debugfs error input < %d\n", irq_first); + return -EINVAL; + } + if (user_val > irq_last) { + dev_err(dev, "debugfs error input > %d\n", irq_last); + return -EINVAL; + } + + free_irq(user_val, &dev->kobj); + kfree(event_name[user_val]); + kfree(dev_attr[user_val]); + + if (dev_attr[user_val]) + sysfs_remove_file(&dev->kobj, &dev_attr[user_val]->attr); + + return buf_size; +} + static const struct file_operations ab8500_bank_fops = { .open = ab8500_bank_open, .write = ab8500_bank_write, @@ -546,17 +692,51 @@ static const struct file_operations ab8500_val_fops = { .owner = THIS_MODULE, }; +static const struct file_operations ab8500_subscribe_fops = { + .open = ab8500_subscribe_unsubscribe_open, + .write = ab8500_subscribe_write, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, + .owner = THIS_MODULE, +}; + +static const struct file_operations ab8500_unsubscribe_fops = { + .open = ab8500_subscribe_unsubscribe_open, + .write = ab8500_unsubscribe_write, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, + .owner = THIS_MODULE, +}; + static struct dentry *ab8500_dir; static struct dentry *ab8500_reg_file; static struct dentry *ab8500_bank_file; static struct dentry *ab8500_address_file; static struct dentry *ab8500_val_file; +static struct dentry *ab8500_subscribe_file; +static struct dentry *ab8500_unsubscribe_file; static int ab8500_debug_probe(struct platform_device *plf) { debug_bank = AB8500_MISC; debug_address = AB8500_REV_REG & 0x00FF; + irq_first = platform_get_irq_byname(plf, "IRQ_FIRST"); + if (irq_first < 0) { + dev_err(&plf->dev, "First irq not found, err %d\n", + irq_first); + return irq_first; + } + + irq_last = platform_get_irq_byname(plf, "IRQ_LAST"); + if (irq_last < 0) { + dev_err(&plf->dev, "Last irq not found, err %d\n", + irq_last); + return irq_last; + } + ab8500_dir = debugfs_create_dir(AB8500_NAME_STRING, NULL); if (!ab8500_dir) goto exit_no_debugfs; @@ -582,8 +762,26 @@ static int ab8500_debug_probe(struct platform_device *plf) if (!ab8500_val_file) goto exit_destroy_address; + ab8500_subscribe_file = + debugfs_create_file("irq-subscribe", + (S_IRUGO | S_IWUGO), ab8500_dir, &plf->dev, + &ab8500_subscribe_fops); + if (!ab8500_subscribe_file) + goto exit_destroy_val; + + ab8500_unsubscribe_file = + debugfs_create_file("irq-unsubscribe", + (S_IRUGO | S_IWUGO), ab8500_dir, &plf->dev, + &ab8500_unsubscribe_fops); + if (!ab8500_unsubscribe_file) + goto exit_destroy_subscribe; + return 0; +exit_destroy_subscribe: + debugfs_remove(ab8500_subscribe_file); +exit_destroy_val: + debugfs_remove(ab8500_val_file); exit_destroy_address: debugfs_remove(ab8500_address_file); exit_destroy_bank: