Re: [PATCH v2 5/6] mailbox: Add generic mechanism for testing Mailbox Controllers

[Jassi Brar]

On Mon, Jul 27, 2015 at 3:14 PM, Lee Jones <lee.jones@xxxxxxxxxx> wrote:
> 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@xxxxxxxxxx>
> ---
>  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@xxxxxxxxxx>
> + *
> + * 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);
>
This is unlikely to work. Those platforms that need to send a 2 part
message, they do :
(a) Signal/Command/Target code via some controller register (via
mbox_send_message).
(b) Setup the payload in Shared-Memory (via tx_prepare).

This test driver assumes both are the same. I think you have to
declare something like

struct mbox_test_message { /* same for TX and RX */
          unsigned sig_len;
          void *signal;               /* rx/tx via mailbox api */
          unsigned pl_len;
          void *payload;           /* rx/tx via shared-memory */
};

> +
> +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;
> +
> +       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;
> +
> +       return mbox_request_channel_byname(client, name);
> +}
> +
> +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");
> +       if (IS_ERR(tdev->tx_channel))
> +               return PTR_ERR(tdev->tx_channel);
> +
> +       tdev->rx_channel = mbox_test_request_channel(pdev, "rx");
> +       if (IS_ERR(tdev->rx_channel))
> +               return PTR_ERR(tdev->rx_channel);
> +
Should it really fail on TX or RX only clients?
It takes write from userspace but shouldn't it also provide data
received to the userspace?

Cheers.
Jassi
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