#include <linux/debugfs.h>
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mailbox_client.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/sched/signal.h>
#define MBOX_MAX_SIG_LEN 8
#define MBOX_MAX_MSG_LEN 128
#define MBOX_BYTES_PER_LINE 16
#define MBOX_HEXDUMP_LINE_LEN ((MBOX_BYTES_PER_LINE * 4) + 2)
#define MBOX_HEXDUMP_MAX_LEN (MBOX_HEXDUMP_LINE_LEN * \
(MBOX_MAX_MSG_LEN / MBOX_BYTES_PER_LINE))
static bool mbox_data_ready;
struct mbox_test_device {
struct device *dev;
void __iomem *tx_mmio;
void __iomem *rx_mmio;
struct mbox_chan *tx_channel;
struct mbox_chan *rx_channel;
char *rx_buffer;
char *signal;
char *message;
spinlock_t lock;
struct mutex mutex;
wait_queue_head_t waitq;
struct fasync_struct *async_queue;
struct dentry *root_debugfs_dir;
};
static ssize_t mbox_test_signal_write(struct file *filp,
const char __user *userbuf,
size_t count, loff_t *ppos)
{
struct mbox_test_device *tdev = filp->private_data;
if (!tdev->tx_channel) {
dev_err(tdev->dev, "Channel cannot do Tx\n");
return -EINVAL;
}
if (count > MBOX_MAX_SIG_LEN) {
dev_err(tdev->dev,
"Signal length %zd greater than max allowed %d\n",
count, MBOX_MAX_SIG_LEN);
return -EINVAL;
}
if (!tdev->signal) {
tdev->signal = kzalloc(MBOX_MAX_SIG_LEN, GFP_KERNEL);
if (!tdev->signal)
return -ENOMEM;
}
if (copy_from_user(tdev->signal, userbuf, count)) {
kfree(tdev->signal);
tdev->signal = NULL;
return -EFAULT;
}
return count;
}
static const struct file_operations mbox_test_signal_ops = {
.write = mbox_test_signal_write,
.open = simple_open,
.llseek = generic_file_llseek,
};
static int mbox_test_message_fasync(int fd, struct file *filp, int on)
{
struct mbox_test_device *tdev = filp->private_data;
return fasync_helper(fd, filp, on, &tdev->async_queue);
}
static ssize_t mbox_test_message_write(struct file *filp,
const char __user *userbuf,
size_t count, loff_t *ppos)
{
struct mbox_test_device *tdev = filp->private_data;
char *message;
void *data;
int ret;
if (!tdev->tx_channel) {
dev_err(tdev->dev, "Channel cannot do Tx\n");
return -EINVAL;
}
if (count > MBOX_MAX_MSG_LEN) {
dev_err(tdev->dev,
"Message length %zd greater than max allowed %d\n",
count, MBOX_MAX_MSG_LEN);
return -EINVAL;
}
message = kzalloc(MBOX_MAX_MSG_LEN, GFP_KERNEL);
if (!message)
return -ENOMEM;
mutex_lock(&tdev->mutex);
tdev->message = message;
ret = copy_from_user(tdev->message, userbuf, count);
if (ret) {
ret = -EFAULT;
goto out;
}
if (tdev->tx_mmio && tdev->signal) {
print_hex_dump_bytes("Client: Sending: Signal: ", DUMP_PREFIX_ADDRESS,
tdev->signal, MBOX_MAX_SIG_LEN);
data = tdev->signal;
} else
data = tdev->message;
print_hex_dump_bytes("Client: Sending: Message: ", DUMP_PREFIX_ADDRESS,
tdev->message, MBOX_MAX_MSG_LEN);
ret = mbox_send_message(tdev->tx_channel, data);
if (ret < 0)
dev_err(tdev->dev, "Failed to send message via mailbox\n");
out:
kfree(tdev->signal);
kfree(tdev->message);
tdev->signal = NULL;
mutex_unlock(&tdev->mutex);
return ret < 0 ? ret : count;
}
static bool mbox_test_message_data_ready(struct mbox_test_device *tdev)
{
bool data_ready;
unsigned long flags;
spin_lock_irqsave(&tdev->lock, flags);
data_ready = mbox_data_ready;
spin_unlock_irqrestore(&tdev->lock, flags);
return data_ready;
}
static ssize_t mbox_test_message_read(struct file *filp, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct mbox_test_device *tdev = filp->private_data;
unsigned long flags;
char *touser, *ptr;
int l = 0;
int ret;
DECLARE_WAITQUEUE(wait, current);
touser = kzalloc(MBOX_HEXDUMP_MAX_LEN + 1, GFP_KERNEL);
if (!touser)
return -ENOMEM;
if (!tdev->rx_channel) {
ret = snprintf(touser, 20, "<NO RX CAPABILITY>\n");
ret = simple_read_from_buffer(userbuf, count, ppos,
touser, ret);
goto kfree_err;
}
add_wait_queue(&tdev->waitq, &wait);
do {
__set_current_state(TASK_INTERRUPTIBLE);
if (mbox_test_message_data_ready(tdev))
break;
if (filp->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
goto waitq_err;
}
if (signal_pending(current)) {
ret = -ERESTARTSYS;
goto waitq_err;
}
schedule();
} while (1);
spin_lock_irqsave(&tdev->lock, flags);
ptr = tdev->rx_buffer;
while (l < MBOX_HEXDUMP_MAX_LEN) {
hex_dump_to_buffer(ptr,
MBOX_BYTES_PER_LINE,
MBOX_BYTES_PER_LINE, 1, touser + l,
MBOX_HEXDUMP_LINE_LEN, true);
ptr += MBOX_BYTES_PER_LINE;
l += MBOX_HEXDUMP_LINE_LEN;
*(touser + (l - 1)) = '\n';
}
*(touser + l) = '\0';
memset(tdev->rx_buffer, 0, MBOX_MAX_MSG_LEN);
mbox_data_ready = false;
spin_unlock_irqrestore(&tdev->lock, flags);
ret = simple_read_from_buffer(userbuf, count, ppos, touser, MBOX_HEXDUMP_MAX_LEN);
waitq_err:
__set_current_state(TASK_RUNNING);
remove_wait_queue(&tdev->waitq, &wait);
kfree_err:
kfree(touser);
return ret;
}
static __poll_t
mbox_test_message_poll(struct file *filp, struct poll_table_struct *wait)
{
struct mbox_test_device *tdev = filp->private_data;
poll_wait(filp, &tdev->waitq, wait);
if (mbox_test_message_data_ready(tdev))
return EPOLLIN | EPOLLRDNORM;
return 0;
}
static const struct file_operations mbox_test_message_ops = {
.write = mbox_test_message_write,
.read = mbox_test_message_read,
.fasync = mbox_test_message_fasync,
.poll = mbox_test_message_poll,
.open = simple_open,
.llseek = generic_file_llseek,
};
static int mbox_test_add_debugfs(struct platform_device *pdev,
struct mbox_test_device *tdev)
{
if (!debugfs_initialized())
return 0;
tdev->root_debugfs_dir = debugfs_create_dir(dev_name(&pdev->dev), NULL);
if (IS_ERR(tdev->root_debugfs_dir)) {
dev_err(&pdev->dev, "Failed to create Mailbox debugfs\n");
return -EINVAL;
}
debugfs_create_file("message", 0600, tdev->root_debugfs_dir,
tdev, &mbox_test_message_ops);
debugfs_create_file("signal", 0200, tdev->root_debugfs_dir,
tdev, &mbox_test_signal_ops);
return 0;
}
static void mbox_test_receive_message(struct mbox_client *client, void *message)
{
struct mbox_test_device *tdev = dev_get_drvdata(client->dev);
unsigned long flags;
spin_lock_irqsave(&tdev->lock, flags);
if (tdev->rx_mmio) {
memcpy_fromio(tdev->rx_buffer, tdev->rx_mmio, MBOX_MAX_MSG_LEN);
print_hex_dump_bytes("Client: Received [MMIO]: ", DUMP_PREFIX_ADDRESS,
tdev->rx_buffer, MBOX_MAX_MSG_LEN);
} else if (message) {
print_hex_dump_bytes("Client: Received [API]: ", DUMP_PREFIX_ADDRESS,
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);
kill_fasync(&tdev->async_queue, SIGIO, POLL_IN);
}
static void mbox_test_prepare_message(struct mbox_client *client, void *message)
{
struct mbox_test_device *tdev = dev_get_drvdata(client->dev);
if (tdev->tx_mmio) {
if (tdev->signal)
memcpy_toio(tdev->tx_mmio, tdev->message, MBOX_MAX_MSG_LEN);
else
memcpy_toio(tdev->tx_mmio, message, MBOX_MAX_MSG_LEN);
}
}
static void mbox_test_message_sent(struct mbox_client *client,
void *message, int r)
{
if (r)
dev_warn(client->dev,
"Client: Message could not be sent: %d\n", r);
else
dev_info(client->dev,
"Client: Message sent\n");
}
static struct mbox_chan *
mbox_test_request_channel(struct platform_device *pdev, const char *name)
{
struct mbox_client *client;
struct mbox_chan *channel;
client = devm_kzalloc(&pdev->dev, sizeof(*client), GFP_KERNEL);
if (!client)
return ERR_PTR(-ENOMEM);
client->dev = &pdev->dev;
client->rx_callback = mbox_test_receive_message;
client->tx_prepare = mbox_test_prepare_message;
client->tx_done = mbox_test_message_sent;
client->tx_block = true;
client->knows_txdone = false;
client->tx_tout = 500;
channel = mbox_request_channel_byname(client, name);
if (IS_ERR(channel)) {
dev_warn(&pdev->dev, "Failed to request %s channel\n", name);
return NULL;
}
return channel;
}
static int mbox_test_probe(struct platform_device *pdev)
{
struct mbox_test_device *tdev;
struct resource *res;
resource_size_t size;
int ret;
tdev = devm_kzalloc(&pdev->dev, sizeof(*tdev), GFP_KERNEL);
if (!tdev)
return -ENOMEM;
tdev->tx_mmio = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
if (PTR_ERR(tdev->tx_mmio) == -EBUSY) {
size = resource_size(res);
tdev->tx_mmio = devm_ioremap(&pdev->dev, res->start, size);
} else if (IS_ERR(tdev->tx_mmio)) {
tdev->tx_mmio = NULL;
}
tdev->rx_mmio = devm_platform_get_and_ioremap_resource(pdev, 1, &res);
if (PTR_ERR(tdev->rx_mmio) == -EBUSY) {
size = resource_size(res);
tdev->rx_mmio = devm_ioremap(&pdev->dev, res->start, size);
} else if (IS_ERR(tdev->rx_mmio)) {
tdev->rx_mmio = tdev->tx_mmio;
}
tdev->tx_channel = mbox_test_request_channel(pdev, "tx");
tdev->rx_channel = mbox_test_request_channel(pdev, "rx");
if (IS_ERR_OR_NULL(tdev->tx_channel) && IS_ERR_OR_NULL(tdev->rx_channel))
return -EPROBE_DEFER;
if (!tdev->rx_channel && (tdev->rx_mmio != tdev->tx_mmio))
tdev->rx_channel = tdev->tx_channel;
tdev->dev = &pdev->dev;
platform_set_drvdata(pdev, tdev);
spin_lock_init(&tdev->lock);
mutex_init(&tdev->mutex);
if (tdev->rx_channel) {
tdev->rx_buffer = devm_kzalloc(&pdev->dev,
MBOX_MAX_MSG_LEN, GFP_KERNEL);
if (!tdev->rx_buffer)
return -ENOMEM;
}
ret = mbox_test_add_debugfs(pdev, tdev);
if (ret)
return ret;
init_waitqueue_head(&tdev->waitq);
dev_info(&pdev->dev, "Successfully registered\n");
return 0;
}
static void mbox_test_remove(struct platform_device *pdev)
{
struct mbox_test_device *tdev = platform_get_drvdata(pdev);
debugfs_remove_recursive(tdev->root_debugfs_dir);
if (tdev->tx_channel)
mbox_free_channel(tdev->tx_channel);
if (tdev->rx_channel)
mbox_free_channel(tdev->rx_channel);
}
static const struct of_device_id mbox_test_match[] = {
{ .compatible = "mailbox-test" },
{},
};
MODULE_DEVICE_TABLE(of, mbox_test_match);
static struct platform_driver mbox_test_driver = {
.driver = {
.name = "mailbox_test",
.of_match_table = mbox_test_match,
},
.probe = mbox_test_probe,
.remove = mbox_test_remove,
};
module_platform_driver(mbox_test_driver);
MODULE_DESCRIPTION("Generic Mailbox Testing Facility");
MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org");
MODULE_LICENSE("GPL v2");
