diff options
Diffstat (limited to 'drivers/misc/aspeed-lpc-snoop.c')
| -rw-r--r-- | drivers/misc/aspeed-lpc-snoop.c | 84 |
1 files changed, 74 insertions, 10 deletions
diff --git a/drivers/misc/aspeed-lpc-snoop.c b/drivers/misc/aspeed-lpc-snoop.c index cb78c98bc78d..2feb4347d67f 100644 --- a/drivers/misc/aspeed-lpc-snoop.c +++ b/drivers/misc/aspeed-lpc-snoop.c @@ -16,12 +16,15 @@ #include <linux/bitops.h> #include <linux/interrupt.h> +#include <linux/fs.h> #include <linux/kfifo.h> #include <linux/mfd/syscon.h> +#include <linux/miscdevice.h> #include <linux/module.h> #include <linux/of.h> #include <linux/of_device.h> #include <linux/platform_device.h> +#include <linux/poll.h> #include <linux/regmap.h> #define DEVICE_NAME "aspeed-lpc-snoop" @@ -59,20 +62,70 @@ struct aspeed_lpc_snoop_model_data { unsigned int has_hicrb_ensnp; }; +struct aspeed_lpc_snoop_channel { + struct kfifo fifo; + wait_queue_head_t wq; + struct miscdevice miscdev; +}; + struct aspeed_lpc_snoop { struct regmap *regmap; int irq; - struct kfifo snoop_fifo[NUM_SNOOP_CHANNELS]; + struct aspeed_lpc_snoop_channel chan[NUM_SNOOP_CHANNELS]; +}; + +static struct aspeed_lpc_snoop_channel *snoop_file_to_chan(struct file *file) +{ + return container_of(file->private_data, + struct aspeed_lpc_snoop_channel, + miscdev); +} + +static ssize_t snoop_file_read(struct file *file, char __user *buffer, + size_t count, loff_t *ppos) +{ + struct aspeed_lpc_snoop_channel *chan = snoop_file_to_chan(file); + unsigned int copied; + int ret = 0; + + if (kfifo_is_empty(&chan->fifo)) { + if (file->f_flags & O_NONBLOCK) + return -EAGAIN; + ret = wait_event_interruptible(chan->wq, + !kfifo_is_empty(&chan->fifo)); + if (ret == -ERESTARTSYS) + return -EINTR; + } + ret = kfifo_to_user(&chan->fifo, buffer, count, &copied); + + return ret ? ret : copied; +} + +static unsigned int snoop_file_poll(struct file *file, + struct poll_table_struct *pt) +{ + struct aspeed_lpc_snoop_channel *chan = snoop_file_to_chan(file); + + poll_wait(file, &chan->wq, pt); + return !kfifo_is_empty(&chan->fifo) ? POLLIN : 0; +} + +static const struct file_operations snoop_fops = { + .owner = THIS_MODULE, + .read = snoop_file_read, + .poll = snoop_file_poll, + .llseek = noop_llseek, }; /* Save a byte to a FIFO and discard the oldest byte if FIFO is full */ -static void put_fifo_with_discard(struct kfifo *fifo, u8 val) +static void put_fifo_with_discard(struct aspeed_lpc_snoop_channel *chan, u8 val) { - if (!kfifo_initialized(fifo)) + if (!kfifo_initialized(&chan->fifo)) return; - if (kfifo_is_full(fifo)) - kfifo_skip(fifo); - kfifo_put(fifo, val); + if (kfifo_is_full(&chan->fifo)) + kfifo_skip(&chan->fifo); + kfifo_put(&chan->fifo, val); + wake_up_interruptible(&chan->wq); } static irqreturn_t aspeed_lpc_snoop_irq(int irq, void *arg) @@ -97,12 +150,12 @@ static irqreturn_t aspeed_lpc_snoop_irq(int irq, void *arg) if (reg & HICR6_STR_SNP0W) { u8 val = (data & SNPWDR_CH0_MASK) >> SNPWDR_CH0_SHIFT; - put_fifo_with_discard(&lpc_snoop->snoop_fifo[0], val); + put_fifo_with_discard(&lpc_snoop->chan[0], val); } if (reg & HICR6_STR_SNP1W) { u8 val = (data & SNPWDR_CH1_MASK) >> SNPWDR_CH1_SHIFT; - put_fifo_with_discard(&lpc_snoop->snoop_fifo[1], val); + put_fifo_with_discard(&lpc_snoop->chan[1], val); } return IRQ_HANDLED; @@ -139,12 +192,22 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop, const struct aspeed_lpc_snoop_model_data *model_data = of_device_get_match_data(dev); + init_waitqueue_head(&lpc_snoop->chan[channel].wq); /* Create FIFO datastructure */ - rc = kfifo_alloc(&lpc_snoop->snoop_fifo[channel], + rc = kfifo_alloc(&lpc_snoop->chan[channel].fifo, SNOOP_FIFO_SIZE, GFP_KERNEL); if (rc) return rc; + lpc_snoop->chan[channel].miscdev.minor = MISC_DYNAMIC_MINOR; + lpc_snoop->chan[channel].miscdev.name = + devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, channel); + lpc_snoop->chan[channel].miscdev.fops = &snoop_fops; + lpc_snoop->chan[channel].miscdev.parent = dev; + rc = misc_register(&lpc_snoop->chan[channel].miscdev); + if (rc) + return rc; + /* Enable LPC snoop channel at requested port */ switch (channel) { case 0: @@ -191,7 +254,8 @@ static void aspeed_lpc_disable_snoop(struct aspeed_lpc_snoop *lpc_snoop, return; } - kfifo_free(&lpc_snoop->snoop_fifo[channel]); + kfifo_free(&lpc_snoop->chan[channel].fifo); + misc_deregister(&lpc_snoop->chan[channel].miscdev); } static int aspeed_lpc_snoop_probe(struct platform_device *pdev) |