From 0c072b46ecc8689be160bfdc750e95ad9879d706 Mon Sep 17 00:00:00 2001
From: Akhil Goyal <akhil.goyal@nxp.com>
Date: Thu, 5 Jul 2018 20:14:21 +0530
Subject: [PATCH] staging: fsl_ppfe: enable hif event from userspace

HIF interrupts are enabled using ioctl from user space,
and epoll wait from user space wakes up when there is an HIF
interrupt.

Signed-off-by: Akhil Goyal <akhil.goyal@nxp.com>
---
 drivers/staging/fsl_ppfe/pfe_cdev.c | 57 +++++++++++++++++++++++++++++++++++++
 drivers/staging/fsl_ppfe/pfe_cdev.h |  5 ++--
 2 files changed, 60 insertions(+), 2 deletions(-)

--- a/drivers/staging/fsl_ppfe/pfe_cdev.c
+++ b/drivers/staging/fsl_ppfe/pfe_cdev.c
@@ -20,11 +20,18 @@
  *  - used for interacting with the kernel layer for link status
  */
 
+#include <linux/eventfd.h>
+#include <linux/irqreturn.h>
+#include <linux/io.h>
+#include <asm/irq.h>
+
 #include "pfe_cdev.h"
+#include "pfe_mod.h"
 
 static int pfe_majno;
 static struct class *pfe_char_class;
 static struct device *pfe_char_dev;
+struct eventfd_ctx *g_trigger;
 
 struct pfe_shared_info link_states[PFE_CDEV_ETH_COUNT];
 
@@ -80,10 +87,44 @@ static ssize_t pfe_cdev_write(struct fil
 
 static int pfe_cdev_release(struct inode *inp, struct file *fp)
 {
+	if (g_trigger) {
+		free_irq(pfe->hif_irq, g_trigger);
+		eventfd_ctx_put(g_trigger);
+		g_trigger = NULL;
+	}
+
 	pr_info("PFE_CDEV: Device successfully closed\n");
 	return 0;
 }
 
+/*
+ * hif_us_isr-
+ * This ISR routine processes Rx/Tx done interrupts from the HIF hardware block
+ */
+static irqreturn_t hif_us_isr(int irq, void *arg)
+{
+	struct eventfd_ctx *trigger = (struct eventfd_ctx *)arg;
+	int int_status;
+	int int_enable_mask;
+
+	/*Read hif interrupt source register */
+	int_status = readl_relaxed(HIF_INT_SRC);
+	int_enable_mask = readl_relaxed(HIF_INT_ENABLE);
+
+	if ((int_status & HIF_INT) == 0)
+		return IRQ_NONE;
+
+	if (int_status & HIF_RXPKT_INT) {
+		int_enable_mask &= ~(HIF_RXPKT_INT);
+		eventfd_signal(trigger, 1);
+	}
+
+	/*Disable interrupts, they will be enabled after they are serviced */
+	writel_relaxed(int_enable_mask, HIF_INT_ENABLE);
+
+	return IRQ_HANDLED;
+}
+
 static long pfe_cdev_ioctl(struct file *fp, unsigned int cmd,
 			   unsigned long arg)
 {
@@ -105,6 +146,22 @@ static long pfe_cdev_ioctl(struct file *
 		pr_debug("Returning state=%d for ETH1\n", *argp);
 		ret = 0;
 		break;
+	case PFE_CDEV_HIF_INTR_EN:
+		/* Return success/failure */
+		g_trigger = eventfd_ctx_fdget(*argp);
+		if (IS_ERR(g_trigger))
+			return PTR_ERR(g_trigger);
+		ret = request_irq(pfe->hif_irq, hif_us_isr, 0, "pfe_hif",
+				  g_trigger);
+		if (ret) {
+			pr_err("%s: failed to get the hif IRQ = %d\n",
+			       __func__, pfe->hif_irq);
+			eventfd_ctx_put(g_trigger);
+			g_trigger = NULL;
+		}
+		pr_debug("request_irq for hif interrupt: %d\n", pfe->hif_irq);
+		ret = 0;
+		break;
 	default:
 		pr_info("Unsupport cmd (%d) for PFE CDEV.\n", cmd);
 		break;
--- a/drivers/staging/fsl_ppfe/pfe_cdev.h
+++ b/drivers/staging/fsl_ppfe/pfe_cdev.h
@@ -43,8 +43,9 @@ struct pfe_shared_info {
 extern struct pfe_shared_info link_states[PFE_CDEV_ETH_COUNT];
 
 /* IOCTL Commands */
-#define PFE_CDEV_ETH0_STATE_GET	0
-#define PFE_CDEV_ETH1_STATE_GET	1
+#define PFE_CDEV_ETH0_STATE_GET		_IOR('R', 0, int)
+#define PFE_CDEV_ETH1_STATE_GET		_IOR('R', 1, int)
+#define PFE_CDEV_HIF_INTR_EN		_IOWR('R', 2, int)
 
 int pfe_cdev_init(void);
 void pfe_cdev_exit(void);