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From 9479d8f12efc845faca4bb1aef9b6e63799a7e5c Mon Sep 17 00:00:00 2001
From: "Arun P. Mohanan" <arun.p.m@linux.intel.com>
Date: Wed, 18 Mar 2020 08:34:43 +0530
Subject: [PATCH] Add poll fops in eSPI driver
Modify eSPI driver to support poll fops.
Signed-off-by: Arun P. Mohanan <arun.p.m@linux.intel.com>
---
drivers/misc/aspeed-espi-slave.c | 85 +++++++++++++++++++++++---------
1 file changed, 61 insertions(+), 24 deletions(-)
diff --git a/drivers/misc/aspeed-espi-slave.c b/drivers/misc/aspeed-espi-slave.c
index 87bc81948694..cb8ed585c69f 100644
--- a/drivers/misc/aspeed-espi-slave.c
+++ b/drivers/misc/aspeed-espi-slave.c
@@ -9,6 +9,7 @@
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
+#include <linux/poll.h>
#include <linux/regmap.h>
#include <linux/reset.h>
#include <linux/sched/signal.h>
@@ -95,6 +96,7 @@ struct aspeed_espi {
spinlock_t pltrstn_lock; /* for PLTRST_N signal sampling */
wait_queue_head_t pltrstn_waitq;
char pltrstn;
+ bool pltrstn_in_avail;
};
static void aspeed_espi_sys_event(struct aspeed_espi *priv)
@@ -127,7 +129,10 @@ static void aspeed_espi_sys_event(struct aspeed_espi *priv)
dev_dbg(priv->dev, "SYSEVT_OOB_RST_WARN: acked\n");
}
if (sts & ASPEED_ESPI_SYSEVT_PLTRSTN || priv->pltrstn == 'U') {
+ spin_lock(&priv->pltrstn_lock);
priv->pltrstn = (evt & ASPEED_ESPI_SYSEVT_PLTRSTN) ? '1' : '0';
+ priv->pltrstn_in_avail = true;
+ spin_unlock(&priv->pltrstn_lock);
wake_up_interruptible(&priv->pltrstn_waitq);
dev_dbg(priv->dev, "SYSEVT_PLTRSTN: %c\n", priv->pltrstn);
}
@@ -269,6 +274,8 @@ static int aspeed_espi_pltrstn_open(struct inode *inode, struct file *filp)
{
if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
return -EACCES;
+ struct aspeed_espi *priv = to_aspeed_espi(filp);
+ priv->pltrstn_in_avail = true ; /*Setting true returns first data after file open*/
return 0;
}
@@ -284,41 +291,71 @@ static ssize_t aspeed_espi_pltrstn_read(struct file *filp, char __user *buf,
spin_lock_irqsave(&priv->pltrstn_lock, flags);
- add_wait_queue(&priv->pltrstn_waitq, &wait);
- set_current_state(TASK_INTERRUPTIBLE);
-
- old_sample = priv->pltrstn;
-
- do {
- char new_sample = priv->pltrstn;
-
- if (filp->f_flags & O_NONBLOCK || old_sample != new_sample) {
- ret = put_user(new_sample, (unsigned long __user *)buf);
- if (!ret)
- ret = sizeof(new_sample);
- } else if (signal_pending(current)) {
- ret = -ERESTARTSYS;
+ if (filp->f_flags & O_NONBLOCK) {
+ if (!priv->pltrstn_in_avail) {
+ ret = -EAGAIN;
+ goto out_unlock;
}
-
- if (!ret) {
- spin_unlock_irqrestore(&priv->pltrstn_lock, flags);
- schedule();
- spin_lock_irqsave(&priv->pltrstn_lock, flags);
+ char data = priv->pltrstn;
+ ret = put_user(data, (unsigned long __user *)buf);
+ if (!ret){
+ ret = sizeof(data);
+ } else{
+ ret = -EAGAIN;
}
- } while (!ret);
-
- remove_wait_queue(&priv->pltrstn_waitq, &wait);
- set_current_state(TASK_RUNNING);
-
+ priv->pltrstn_in_avail = false;
+ } else {
+ add_wait_queue(&priv->pltrstn_waitq, &wait);
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ old_sample = priv->pltrstn;
+
+ do {
+ char new_sample = priv->pltrstn;
+
+ if (old_sample != new_sample) {
+ ret = put_user(new_sample,
+ (unsigned long __user *)buf);
+ if (!ret)
+ ret = sizeof(new_sample);
+ } else if (signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ }
+
+ if (!ret) {
+ spin_unlock_irqrestore(&priv->pltrstn_lock,
+ flags);
+ schedule();
+ spin_lock_irqsave(&priv->pltrstn_lock, flags);
+ }
+ } while (!ret);
+
+ remove_wait_queue(&priv->pltrstn_waitq, &wait);
+ set_current_state(TASK_RUNNING);
+ }
+out_unlock:
spin_unlock_irqrestore(&priv->pltrstn_lock, flags);
return ret;
}
+static unsigned int aspeed_espi_pltrstn_poll(struct file *file,
+ poll_table *wait)
+{
+ struct aspeed_espi *priv = to_aspeed_espi(file);
+ unsigned int mask = 0;
+ poll_wait(file, &priv->pltrstn_waitq, wait);
+
+ if (priv->pltrstn_in_avail)
+ mask |= POLLIN;
+ return mask;
+}
+
static const struct file_operations aspeed_espi_pltrstn_fops = {
.owner = THIS_MODULE,
.open = aspeed_espi_pltrstn_open,
.read = aspeed_espi_pltrstn_read,
+ .poll = aspeed_espi_pltrstn_poll,
};
static const struct regmap_config aspeed_espi_regmap_cfg = {
--
2.17.1
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