From e339c80af95e14de3712d69ddea09a3868fa14cd Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Thu, 28 Sep 2017 11:18:53 +0100 Subject: [PATCH] mailbox: mailbox-test: don't rely on rx_buffer content to signal data ready Git-commit: e339c80af95e14de3712d69ddea09a3868fa14cd Patch-mainline: v4.15-rc1 References: bsc#1051510 Currently we rely on the first byte of the Rx buffer to check if there's any data available to be read. If the first byte of the received buffer is zero (i.e. null character), then we fail to signal that data is available even when it's available. Instead introduce a boolean variable to track the data availability and update it in the channel receive callback as ready and clear it when the data is read. Signed-off-by: Sudeep Holla Signed-off-by: Jassi Brar Acked-by: Takashi Iwai --- drivers/mailbox/mailbox-test.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/mailbox/mailbox-test.c b/drivers/mailbox/mailbox-test.c index 97fb956bb6e0..93f3d4d61fa7 100644 --- a/drivers/mailbox/mailbox-test.c +++ b/drivers/mailbox/mailbox-test.c @@ -30,6 +30,7 @@ #define MBOX_HEXDUMP_MAX_LEN (MBOX_HEXDUMP_LINE_LEN * \ (MBOX_MAX_MSG_LEN / MBOX_BYTES_PER_LINE)) +static bool mbox_data_ready; static struct dentry *root_debugfs_dir; struct mbox_test_device { @@ -152,16 +153,14 @@ static ssize_t mbox_test_message_write(struct file *filp, static bool mbox_test_message_data_ready(struct mbox_test_device *tdev) { - unsigned char data; + bool data_ready; unsigned long flags; spin_lock_irqsave(&tdev->lock, flags); - data = tdev->rx_buffer[0]; + data_ready = mbox_data_ready; spin_unlock_irqrestore(&tdev->lock, flags); - if (data != '\0') - return true; - return false; + return data_ready; } static ssize_t mbox_test_message_read(struct file *filp, char __user *userbuf, @@ -223,6 +222,7 @@ static ssize_t mbox_test_message_read(struct file *filp, char __user *userbuf, *(touser + l) = '\0'; memset(tdev->rx_buffer, 0, MBOX_MAX_MSG_LEN); + mbox_data_ready = false; spin_unlock_irqrestore(&tdev->lock, flags); @@ -292,6 +292,7 @@ static void mbox_test_receive_message(struct mbox_client *client, void *message) message, MBOX_MAX_MSG_LEN); memcpy(tdev->rx_buffer, message, MBOX_MAX_MSG_LEN); } + mbox_data_ready = true; spin_unlock_irqrestore(&tdev->lock, flags); wake_up_interruptible(&tdev->waitq); -- 2.18.0