Re: [PATCH v2 5/6] 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 <redacted>
---
 drivers/mailbox/Kconfig        |   7 ++
 drivers/mailbox/Makefile       |   2 +
 drivers/mailbox/mailbox-test.c | 210 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 219 insertions(+)
 create mode 100644 drivers/mailbox/mailbox-test.c

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 2cc4c39..7720bde 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig

@@ -77,4 +77,11 @@ 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 7cb4766..92435ef 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 0000000..10bfe3a
--- /dev/null
+++ b/drivers/mailbox/mailbox-test.c

@@ -0,0 +1,210 @@
+/*
+ * Copyright (C) 2015 ST Microelectronics
+ *
+ * Author: Lee Jones <lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.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_MSG_LEN 128
+
+static struct dentry *root_debugfs_dir;
+
+struct mbox_test_device {
+       struct device           *dev;
+       struct mbox_chan        *tx_channel;
+       struct mbox_chan        *rx_channel;
+       void __iomem            *mmio;
+
+};
+
+static ssize_t mbox_test_write(struct file *filp,
+                              const char __user *userbuf,
+                              size_t count, loff_t *ppos)
+{
+       struct mbox_test_device *tdev = filp->private_data;
+       char *message;
+       int ret;
+
+       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;
+       }
+
+       message = kzalloc(count, GFP_KERNEL);
+       if (!message)
+               return -ENOMEM;
+
+       ret = copy_from_user(message, userbuf, count);
+       if (ret)
+               return -EFAULT;
+
+       print_hex_dump(KERN_ERR, "Client: Sending: ", DUMP_PREFIX_ADDRESS,
+                      16, 1, message, 16, true);
+
+       ret = mbox_send_message(tdev->tx_channel, message);
+       if (ret < 0)
+               dev_err(tdev->dev, "Failed to send message via mailbox\n");
+
+       kfree(message);
+
+       return ret < 0 ? ret : count;
+}
+
+static const struct file_operations mbox_test_ops = {
+       .write  = mbox_test_write,
+       .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("send-message", 0200, root_debugfs_dir,
+                           tdev, &mbox_test_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);
+
+       if (!tdev->mmio) {
+               dev_info(tdev->dev, "Client: Recived something [read mmio]\n");
+               return;
+       }
+
+       print_hex_dump(KERN_ERR, "Client: from co-proc: ", DUMP_PREFIX_ADDRESS,
+                      16, 1, tdev->mmio, MBOX_MAX_MSG_LEN, true);
+}
+
+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)
+               memcpy(tdev->mmio, message, MBOX_MAX_MSG_LEN);