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Date: Wed, 12 Aug 2015 11:23:28 +0100
From: Lee Jones <lee.jones@...aro.org>
To: Jassi Brar <jassisinghbrar@...il.com>
Cc: "linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
kernel@...inux.com, Devicetree List <devicetree@...r.kernel.org>
Subject: Re: [PATCH v2 5/6] mailbox: Add generic mechanism for testing
Mailbox Controllers
On Mon, 10 Aug 2015, Jassi Brar wrote:
> On Mon, Jul 27, 2015 at 3:14 PM, Lee Jones <lee.jones@...aro.org> 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@...aro.org>
> > ---
> > 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@...aro.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);
> >
> 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
This driver assumes that the framework will call client->tx_prepare()
first, which satisfies (b). It then assumes controller->send_data()
will be invoked, which will send the platform specific
signal/command/target code, which then satisfies (a).
In what way does it assume they are the same?
> 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 */
> };
How do you think this should be set and use these?
> > +
> > +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?
Good question. Probably not, but I guess we'd need a flag for that.
> It takes write from userspace but shouldn't it also provide data
> received to the userspace?
Currently we only print the returning message. If you want me to put
it in a userspace file too, that's not an issue.
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
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