mailbox: Add generic mechanism for testing Mailbox Controllers

This particular Client implementation uses shared memory in order
to pass messages between Mailbox users; however, it can be easily
hacked to support any type of Controller.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

3 files changed, 370 insertions, 0 deletions

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 7b53386f9415..546d05f4358a 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -78,4 +78,11 @@ config STI_MBOX
           Mailbox implementation for STMicroelectonics family chips with
           hardware for interprocessor communication.
 
+config MAILBOX_TEST
+        tristate "Mailbox Test Client"
+        depends on OF
+        help
+          Test client to help with testing new Controller driver
+          implementations.
+
 endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 7cb476643833..92435ef11f26 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -2,6 +2,8 @@
 
 obj-$(CONFIG_MAILBOX)           += mailbox.o
 
+obj-$(CONFIG_MAILBOX_TEST)      += mailbox-test.o
+
 obj-$(CONFIG_ARM_MHU)   += arm_mhu.o
 
 obj-$(CONFIG_PL320_MBOX)        += pl320-ipc.o
diff --git a/drivers/mailbox/mailbox-test.c b/drivers/mailbox/mailbox-test.c
new file mode 100644
index 000000000000..cac1ba2f3e22
--- /dev/null
+++ b/drivers/mailbox/mailbox-test.c
@@ -0,0 +1,361 @@
+/*
+ * Copyright (C) 2015 ST Microelectronics
+ *
+ * Author: Lee Jones <lee.jones@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/uaccess.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 struct dentry *root_debugfs_dir;
+
+struct mbox_test_device {
+        struct device           *dev;
+        void __iomem            *mmio;
+        struct mbox_chan        *tx_channel;
+        struct mbox_chan        *rx_channel;
+        char                    *rx_buffer;
+        char                    *signal;
+        char                    *message;
+        spinlock_t              lock;
+};
+
+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;
+        int ret;
+
+        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 %d greater than max allowed %d\n",
+                        count, MBOX_MAX_SIG_LEN);
+                return -EINVAL;
+        }
+
+        tdev->signal = kzalloc(MBOX_MAX_SIG_LEN, GFP_KERNEL);
+        if (!tdev->signal)
+                return -ENOMEM;
+
+        ret = copy_from_user(tdev->signal, userbuf, count);
+        if (ret) {
+                kfree(tdev->signal);
+                return -EFAULT;
+        }
+
+        return ret < 0 ? ret : count;
+}
+
+static const struct file_operations mbox_test_signal_ops = {
+        .write  = mbox_test_signal_write,
+        .open   = simple_open,
+        .llseek = generic_file_llseek,
+};
+
+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;
+        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 %d greater than max allowed %d\n",
+                        count, MBOX_MAX_MSG_LEN);
+                return -EINVAL;
+        }
+
+        tdev->message = kzalloc(MBOX_MAX_MSG_LEN, GFP_KERNEL);
+        if (!tdev->message)
+                return -ENOMEM;
+
+        ret = copy_from_user(tdev->message, userbuf, count);
+        if (ret) {
+                ret = -EFAULT;
+                goto out;
+        }
+
+        /*
+         * A separate signal is only of use if there is
+         * MMIO to subsequently pass the message through
+         */
+        if (tdev->mmio && tdev->signal) {
+                print_hex_dump(KERN_INFO, "Client: Sending: Signal: ", DUMP_PREFIX_ADDRESS,
+                               MBOX_BYTES_PER_LINE, 1, tdev->signal, MBOX_MAX_SIG_LEN, true);
+
+                data = tdev->signal;
+        } else
+                data = tdev->message;
+
+        print_hex_dump(KERN_INFO, "Client: Sending: Message: ", DUMP_PREFIX_ADDRESS,
+                       MBOX_BYTES_PER_LINE, 1, tdev->message, MBOX_MAX_MSG_LEN, true);
+
+        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);
+
+        return ret < 0 ? ret : count;
+}
+
+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;
+
+        touser = kzalloc(MBOX_HEXDUMP_MAX_LEN, 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 out;
+        }
+
+        if (tdev->rx_buffer[0] == '\0') {
+                ret = snprintf(touser, 9, "<EMPTY>\n");
+                ret = simple_read_from_buffer(userbuf, count, ppos,
+                                              touser, ret);
+                goto out;
+        }
+
+        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);
+
+        spin_unlock_irqrestore(&tdev->lock, flags);
+
+        ret = simple_read_from_buffer(userbuf, count, ppos, touser, MBOX_HEXDUMP_MAX_LEN);
+out:
+        kfree(touser);
+        return ret;
+}
+
+static const struct file_operations mbox_test_message_ops = {
+        .write  = mbox_test_message_write,
+        .read   = mbox_test_message_read,
+        .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;
+
+        root_debugfs_dir = debugfs_create_dir("mailbox", NULL);
+        if (!root_debugfs_dir) {
+                dev_err(&pdev->dev, "Failed to create Mailbox debugfs\n");
+                return -EINVAL;
+        }
+
+        debugfs_create_file("message", 0600, root_debugfs_dir,
+                            tdev, &mbox_test_message_ops);
+
+        debugfs_create_file("signal", 0200, 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->mmio) {
+                print_hex_dump(KERN_INFO, "Client: Received [MMIO]: ",
+                               DUMP_PREFIX_ADDRESS, MBOX_BYTES_PER_LINE, 1,
+                               tdev->mmio, MBOX_MAX_MSG_LEN, true);
+                memcpy(tdev->rx_buffer, tdev->mmio, MBOX_MAX_MSG_LEN);
+
+        } else if (message) {
+                print_hex_dump(KERN_INFO, "Client: Received [API]: ",
+                               DUMP_PREFIX_ADDRESS, MBOX_BYTES_PER_LINE, 1,
+                               message, MBOX_MAX_MSG_LEN, true);
+                memcpy(tdev->rx_buffer, message, MBOX_MAX_MSG_LEN);
+        }
+        spin_unlock_irqrestore(&tdev->lock, flags);
+}
+
+static void mbox_test_prepare_message(struct mbox_client *client, void *message)
+{
+        struct mbox_test_device *tdev = dev_get_drvdata(client->dev);
+
+        if (tdev->mmio) {
+                if (tdev->signal)
+                        memcpy(tdev->mmio, tdev->message, MBOX_MAX_MSG_LEN);
+                else
+                        memcpy(tdev->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;
+        int ret;
+
+        tdev = devm_kzalloc(&pdev->dev, sizeof(*tdev), GFP_KERNEL);
+        if (!tdev)
+                return -ENOMEM;
+
+        /* It's okay for MMIO to be NULL */
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        tdev->mmio = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(tdev->mmio))
+                tdev->mmio = NULL;
+
+        tdev->tx_channel = mbox_test_request_channel(pdev, "tx");
+        tdev->rx_channel = mbox_test_request_channel(pdev, "rx");
+
+        if (!tdev->tx_channel && !tdev->tx_channel)
+                return -EPROBE_DEFER;
+
+        tdev->dev = &pdev->dev;
+        platform_set_drvdata(pdev, tdev);
+
+        spin_lock_init(&tdev->lock);
+
+        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;
+
+        dev_info(&pdev->dev, "Successfully registered\n");
+
+        return 0;
+}
+
+static int mbox_test_remove(struct platform_device *pdev)
+{
+        struct mbox_test_device *tdev = platform_get_drvdata(pdev);
+
+        debugfs_remove_recursive(root_debugfs_dir);
+
+        if (tdev->tx_channel)
+                mbox_free_channel(tdev->tx_channel);
+        if (tdev->rx_channel)
+                mbox_free_channel(tdev->rx_channel);
+
+        return 0;
+}
+
+static const struct of_device_id mbox_test_match[] = {
+        { .compatible = "mailbox_test" },
+        {},
+};
+
+static struct platform_driver mbox_test_driver = {
+        .driver = {
+                .name = "mailbox_sti_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");