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// SPDX-License-Identifier: GPL-2.0
/*
* Microchip PolarFire SoC (MPFS) system controller driver
*
* Copyright (c) 2020-2021 Microchip Corporation. All rights reserved.
*
* Author: Conor Dooley <conor.dooley@microchip.com>
*
*/
#include <linux/slab.h>
#include <linux/kref.h>
#include <linux/module.h>
#include <linux/jiffies.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/mailbox_client.h>
#include <linux/platform_device.h>
#include <soc/microchip/mpfs.h>
/*
* This timeout must be long, as some services (example: image authentication)
* take significant time to complete
*/
#define MPFS_SYS_CTRL_TIMEOUT_MS 30000
static DEFINE_MUTEX(transaction_lock);
struct mpfs_sys_controller {
struct mbox_client client;
struct mbox_chan *chan;
struct completion c;
struct kref consumers;
};
int mpfs_blocking_transaction(struct mpfs_sys_controller *sys_controller, struct mpfs_mss_msg *msg)
{
unsigned long timeout = msecs_to_jiffies(MPFS_SYS_CTRL_TIMEOUT_MS);
int ret;
ret = mutex_lock_interruptible(&transaction_lock);
if (ret)
return ret;
reinit_completion(&sys_controller->c);
ret = mbox_send_message(sys_controller->chan, msg);
if (ret < 0) {
dev_warn(sys_controller->client.dev, "MPFS sys controller service timeout\n");
goto out;
}
/*
* Unfortunately, the system controller will only deliver an interrupt
* if a service succeeds. mbox_send_message() will block until the busy
* flag is gone. If the busy flag is gone but no interrupt has arrived
* to trigger the rx callback then the service can be deemed to have
* failed.
* The caller can then interrogate msg::response::resp_status to
* determine the cause of the failure.
* mbox_send_message() returns positive integers in the success path, so
* ret needs to be cleared if we do get an interrupt.
*/
if (!wait_for_completion_timeout(&sys_controller->c, timeout)) {
ret = -EBADMSG;
dev_warn(sys_controller->client.dev, "MPFS sys controller service failed\n");
} else {
ret = 0;
}
out:
mutex_unlock(&transaction_lock);
return ret;
}
EXPORT_SYMBOL(mpfs_blocking_transaction);
static void mpfs_sys_controller_rx_callback(struct mbox_client *client, void *msg)
{
struct mpfs_sys_controller *sys_controller =
container_of(client, struct mpfs_sys_controller, client);
complete(&sys_controller->c);
}
static void mpfs_sys_controller_delete(struct kref *kref)
{
struct mpfs_sys_controller *sys_controller =
container_of(kref, struct mpfs_sys_controller, consumers);
mbox_free_channel(sys_controller->chan);
kfree(sys_controller);
}
static void mpfs_sys_controller_put(void *data)
{
struct mpfs_sys_controller *sys_controller = data;
kref_put(&sys_controller->consumers, mpfs_sys_controller_delete);
}
static struct platform_device subdevs[] = {
{
.name = "mpfs-rng",
.id = -1,
},
{
.name = "mpfs-generic-service",
.id = -1,
}
};
static int mpfs_sys_controller_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct mpfs_sys_controller *sys_controller;
int i, ret;
sys_controller = kzalloc(sizeof(*sys_controller), GFP_KERNEL);
if (!sys_controller)
return -ENOMEM;
sys_controller->client.dev = dev;
sys_controller->client.rx_callback = mpfs_sys_controller_rx_callback;
sys_controller->client.tx_block = 1U;
sys_controller->client.tx_tout = msecs_to_jiffies(MPFS_SYS_CTRL_TIMEOUT_MS);
sys_controller->chan = mbox_request_channel(&sys_controller->client, 0);
if (IS_ERR(sys_controller->chan)) {
ret = dev_err_probe(dev, PTR_ERR(sys_controller->chan),
"Failed to get mbox channel\n");
kfree(sys_controller);
return ret;
}
init_completion(&sys_controller->c);
kref_init(&sys_controller->consumers);
platform_set_drvdata(pdev, sys_controller);
dev_info(&pdev->dev, "Registered MPFS system controller\n");
for (i = 0; i < ARRAY_SIZE(subdevs); i++) {
subdevs[i].dev.parent = dev;
if (platform_device_register(&subdevs[i]))
dev_warn(dev, "Error registering sub device %s\n", subdevs[i].name);
}
return 0;
}
static int mpfs_sys_controller_remove(struct platform_device *pdev)
{
struct mpfs_sys_controller *sys_controller = platform_get_drvdata(pdev);
mpfs_sys_controller_put(sys_controller);
return 0;
}
static const struct of_device_id mpfs_sys_controller_of_match[] = {
{.compatible = "microchip,mpfs-sys-controller", },
{},
};
MODULE_DEVICE_TABLE(of, mpfs_sys_controller_of_match);
struct mpfs_sys_controller *mpfs_sys_controller_get(struct device *dev)
{
const struct of_device_id *match;
struct mpfs_sys_controller *sys_controller;
int ret;
if (!dev->parent)
goto err_no_device;
match = of_match_node(mpfs_sys_controller_of_match, dev->parent->of_node);
of_node_put(dev->parent->of_node);
if (!match)
goto err_no_device;
sys_controller = dev_get_drvdata(dev->parent);
if (!sys_controller)
goto err_bad_device;
if (!kref_get_unless_zero(&sys_controller->consumers))
goto err_bad_device;
ret = devm_add_action_or_reset(dev, mpfs_sys_controller_put, sys_controller);
if (ret)
return ERR_PTR(ret);
return sys_controller;
err_no_device:
dev_dbg(dev, "Parent device was not an MPFS system controller\n");
return ERR_PTR(-ENODEV);
err_bad_device:
dev_dbg(dev, "MPFS system controller found but could not register as a sub device\n");
return ERR_PTR(-EPROBE_DEFER);
}
EXPORT_SYMBOL(mpfs_sys_controller_get);
static struct platform_driver mpfs_sys_controller_driver = {
.driver = {
.name = "mpfs-sys-controller",
.of_match_table = mpfs_sys_controller_of_match,
},
.probe = mpfs_sys_controller_probe,
.remove = mpfs_sys_controller_remove,
};
module_platform_driver(mpfs_sys_controller_driver);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
MODULE_DESCRIPTION("MPFS system controller driver");
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