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From 7094f4d8efea8e059c965ba70c73d5226af392cb Mon Sep 17 00:00:00 2001
From: "Arun P. Mohanan" <arun.p.m@linux.intel.com>
Date: Wed, 11 Mar 2020 17:23:49 +0530
Subject: [PATCH] [Mailbox] Enabling interrupt based mailbox
Modifying the mailbox driver to use FIFO queue while using interrupt.
Signed-off-by: Arun P. Mohanan <arun.p.m@linux.intel.com>
---
drivers/soc/aspeed/aspeed-lpc-mbox.c | 101 ++++++++++++++++++---------
1 file changed, 68 insertions(+), 33 deletions(-)
diff --git a/drivers/soc/aspeed/aspeed-lpc-mbox.c b/drivers/soc/aspeed/aspeed-lpc-mbox.c
index 795107206022..99f38a4e4550 100644
--- a/drivers/soc/aspeed/aspeed-lpc-mbox.c
+++ b/drivers/soc/aspeed/aspeed-lpc-mbox.c
@@ -12,10 +12,11 @@
#include <linux/poll.h>
#include <linux/regmap.h>
#include <linux/slab.h>
+#include <linux/kfifo.h>
#define DEVICE_NAME "aspeed-mbox"
-#define MBX_USE_INTERRUPT 0
+#define MBX_USE_INTERRUPT 1
#define ASPEED_MBOX_NUM_REGS 16
@@ -29,6 +30,7 @@
#define ASPEED_MBOX_HOST_CTRL 0x4c
#define ASPEED_MBOX_INTERRUPT_0 0x50
#define ASPEED_MBOX_INTERRUPT_1 0x54
+#define MBOX_FIFO_SIZE 64
struct aspeed_mbox {
struct miscdevice miscdev;
@@ -38,6 +40,8 @@ struct aspeed_mbox {
int irq;
wait_queue_head_t queue;
struct mutex mutex;
+ struct kfifo fifo;
+ spinlock_t lock;
};
static atomic_t aspeed_mbox_open_count = ATOMIC_INIT(0);
@@ -74,20 +78,37 @@ static struct aspeed_mbox *file_mbox(struct file *file)
return container_of(file->private_data, struct aspeed_mbox, miscdev);
}
+/* Save a byte to a FIFO and discard the oldest byte if FIFO is full */
+static void put_fifo_with_discard(struct aspeed_mbox *mbox, u8 val)
+{
+ if (!kfifo_initialized(&mbox->fifo))
+ return;
+ if (kfifo_is_full(&mbox->fifo))
+ kfifo_skip(&mbox->fifo);
+ kfifo_put(&mbox->fifo, val);
+}
+
static int aspeed_mbox_open(struct inode *inode, struct file *file)
{
#if MBX_USE_INTERRUPT
struct aspeed_mbox *mbox = file_mbox(file);
+ int i;
#endif
if (atomic_inc_return(&aspeed_mbox_open_count) == 1) {
#if MBX_USE_INTERRUPT
/*
- * Clear the interrupt status bit if it was left on and unmask
- * interrupts.
- * ASPEED_MBOX_CTRL_RECV bit is W1C, this also unmasks in 1 step
+ * Reset the FIFO while opening to clear the old cached data
+ * and load the FIFO with latest mailbox register values.
*/
- aspeed_mbox_outb(mbox, ASPEED_MBOX_CTRL_RECV, ASPEED_MBOX_BMC_CTRL);
+ kfifo_reset(&mbox->fifo);
+ spin_lock_irq(&mbox->lock);
+ for (i = 0; i < ASPEED_MBOX_NUM_REGS; i++) {
+ put_fifo_with_discard(mbox,
+ aspeed_mbox_inb(mbox, ASPEED_MBOX_DATA_0 + (i * 4)));
+ }
+ spin_unlock_irq(&mbox->lock);
+
#endif
return 0;
}
@@ -102,6 +123,8 @@ static ssize_t aspeed_mbox_read(struct file *file, char __user *buf,
struct aspeed_mbox *mbox = file_mbox(file);
char __user *p = buf;
ssize_t ret;
+ unsigned int copied;
+ unsigned long flags;
int i;
if (!access_ok(buf, count))
@@ -111,15 +134,29 @@ static ssize_t aspeed_mbox_read(struct file *file, char __user *buf,
return -EINVAL;
#if MBX_USE_INTERRUPT
- if (file->f_flags & O_NONBLOCK) {
- if (!(aspeed_mbox_inb(mbox, ASPEED_MBOX_BMC_CTRL) &
- ASPEED_MBOX_CTRL_RECV))
+ /*
+ * Restrict count as per the number of mailbox registers
+ * if interrupt is enabled.
+ */
+ if (count != ASPEED_MBOX_NUM_REGS)
+ return -EINVAL;
+
+ if (kfifo_is_empty(&mbox->fifo)) {
+ if (file->f_flags & O_NONBLOCK){
return -EAGAIN;
- } else if (wait_event_interruptible(mbox->queue,
- aspeed_mbox_inb(mbox, ASPEED_MBOX_BMC_CTRL) &
- ASPEED_MBOX_CTRL_RECV)) {
- return -ERESTARTSYS;
+ }
+ ret = wait_event_interruptible(mbox->queue,
+ !kfifo_is_empty(&mbox->fifo));
+ if (ret == -ERESTARTSYS){
+ return -EINTR;
+ }
}
+
+ spin_lock_irqsave(&mbox->lock, flags);
+ ret = kfifo_to_user(&mbox->fifo, buf, count, &copied);
+ spin_unlock_irqrestore(&mbox->lock, flags);
+ return ret ? ret : copied;
+
#endif
mutex_lock(&mbox->mutex);
@@ -134,11 +171,6 @@ static ssize_t aspeed_mbox_read(struct file *file, char __user *buf,
p++;
count--;
}
-
-#if MBX_USE_INTERRUPT
- /* ASPEED_MBOX_CTRL_RECV bit is write to clear, this also unmasks in 1 step */
- aspeed_mbox_outb(mbox, ASPEED_MBOX_CTRL_RECV, ASPEED_MBOX_BMC_CTRL);
-#endif
ret = p - buf;
out_unlock:
@@ -186,16 +218,9 @@ static ssize_t aspeed_mbox_write(struct file *file, const char __user *buf,
static unsigned int aspeed_mbox_poll(struct file *file, poll_table *wait)
{
struct aspeed_mbox *mbox = file_mbox(file);
- unsigned int mask = 0;
poll_wait(file, &mbox->queue, wait);
-
-#if MBX_USE_INTERRUPT
- if (aspeed_mbox_inb(mbox, ASPEED_MBOX_BMC_CTRL) & ASPEED_MBOX_CTRL_RECV)
-#endif
- mask |= POLLIN;
-
- return mask;
+ return !kfifo_is_empty(&mbox->fifo) ? POLLIN : 0;
}
static int aspeed_mbox_release(struct inode *inode, struct file *file)
@@ -220,19 +245,23 @@ static irqreturn_t aspeed_mbox_irq(int irq, void *arg)
#if MBX_USE_INTERRUPT
int i;
-// if (!(aspeed_mbox_inb(mbox, ASPEED_MBOX_BMC_CTRL) & ASPEED_MBOX_CTRL_RECV))
-// return IRQ_NONE;
-
- printk(KERN_ERR "BMC_CTRL: 0x%02x\n",
+ dev_dbg(mbox->miscdev.parent, "BMC_CTRL11: 0x%02x\n",
aspeed_mbox_inb(mbox, ASPEED_MBOX_BMC_CTRL));
- printk(KERN_ERR "STATUS_0: 0x%02x\n",
+ dev_dbg(mbox->miscdev.parent, "STATUS_0: 0x%02x\n",
aspeed_mbox_inb(mbox, ASPEED_MBOX_STATUS_0));
- printk(KERN_ERR "STATUS_1: 0x%02x\n",
+ dev_dbg(mbox->miscdev.parent, "STATUS_1: 0x%02x\n",
aspeed_mbox_inb(mbox, ASPEED_MBOX_STATUS_1));
for (i = 0; i < ASPEED_MBOX_NUM_REGS; i++) {
- printk(KERN_ERR "DATA_%d: 0x%02x\n", i,
+ dev_dbg(mbox->miscdev.parent, "DATA_%d: 0x%02x\n", i,
aspeed_mbox_inb(mbox, ASPEED_MBOX_DATA_0 + (i * 4)));
}
+
+ spin_lock(&mbox->lock);
+ for (i = 0; i < ASPEED_MBOX_NUM_REGS; i++) {
+ put_fifo_with_discard(mbox,
+ aspeed_mbox_inb(mbox, ASPEED_MBOX_DATA_0 + (i * 4)));
+ }
+ spin_unlock(&mbox->lock);
#endif
/* Clear interrupt status */
@@ -249,7 +278,6 @@ static int aspeed_mbox_config_irq(struct aspeed_mbox *mbox,
{
struct device *dev = &pdev->dev;
int rc;
-
mbox->irq = platform_get_irq(pdev, 0);
if (!mbox->irq)
return -ENODEV;
@@ -300,6 +328,7 @@ static int aspeed_mbox_probe(struct platform_device *pdev)
return -ENODEV;
}
+ spin_lock_init(&mbox->lock);
mutex_init(&mbox->mutex);
init_waitqueue_head(&mbox->queue);
@@ -316,6 +345,11 @@ static int aspeed_mbox_probe(struct platform_device *pdev)
return rc;
}
+ /* Create FIFO data structure */
+ rc = kfifo_alloc(&mbox->fifo, MBOX_FIFO_SIZE, GFP_KERNEL);
+ if (rc)
+ return rc;
+
mbox->miscdev.minor = MISC_DYNAMIC_MINOR;
mbox->miscdev.name = DEVICE_NAME;
mbox->miscdev.fops = &aspeed_mbox_fops;
@@ -349,6 +383,7 @@ static int aspeed_mbox_remove(struct platform_device *pdev)
misc_deregister(&mbox->miscdev);
clk_disable_unprepare(mbox->clk);
+ kfifo_free(&mbox->fifo);
return 0;
}
--
2.17.1
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