// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2018-2019, Intel Corporation
 */

#include <linux/arm-smccc.h>
#include <linux/bitfield.h>
#include <linux/completion.h>
#include <linux/kobject.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/firmware/intel/stratix10-svc-client.h>
#include <linux/string.h>
#include <linux/sysfs.h>

#define RSU_STATE_MASK			GENMASK_ULL(31, 0)
#define RSU_VERSION_MASK		GENMASK_ULL(63, 32)
#define RSU_ERROR_LOCATION_MASK		GENMASK_ULL(31, 0)
#define RSU_ERROR_DETAIL_MASK		GENMASK_ULL(63, 32)

#define RSU_TIMEOUT	(msecs_to_jiffies(SVC_RSU_REQUEST_TIMEOUT_MS))

#define INVALID_RETRY_COUNTER		0xFFFFFFFF

typedef void (*rsu_callback)(struct stratix10_svc_client *client,
			     struct stratix10_svc_cb_data *data);
/**
 * struct stratix10_rsu_priv - rsu data structure
 * @chan: pointer to the allocated service channel
 * @client: active service client
 * @completion: state for callback completion
 * @lock: a mutex to protect callback completion state
 * @status.current_image: address of image currently running in flash
 * @status.fail_image: address of failed image in flash
 * @status.version: the version number of RSU firmware
 * @status.state: the state of RSU system
 * @status.error_details: error code
 * @status.error_location: the error offset inside the image that failed
 * @retry_counter: the current image's retry counter
 */
struct stratix10_rsu_priv {
	struct stratix10_svc_chan *chan;
	struct stratix10_svc_client client;
	struct completion completion;
	struct mutex lock;
	struct {
		unsigned long current_image;
		unsigned long fail_image;
		unsigned int version;
		unsigned int state;
		unsigned int error_details;
		unsigned int error_location;
	} status;
	unsigned int retry_counter;
};

/**
 * rsu_status_callback() - Status callback from Intel Service Layer
 * @client: pointer to service client
 * @data: pointer to callback data structure
 *
 * Callback from Intel service layer for RSU status request. Status is
 * only updated after a system reboot, so a get updated status call is
 * made during driver probe.
 */
static void rsu_status_callback(struct stratix10_svc_client *client,
				struct stratix10_svc_cb_data *data)
{
	struct stratix10_rsu_priv *priv = client->priv;
	struct arm_smccc_res *res = (struct arm_smccc_res *)data->kaddr1;

	if (data->status == BIT(SVC_STATUS_RSU_OK)) {
		priv->status.version = FIELD_GET(RSU_VERSION_MASK,
						 res->a2);
		priv->status.state = FIELD_GET(RSU_STATE_MASK, res->a2);
		priv->status.fail_image = res->a1;
		priv->status.current_image = res->a0;
		priv->status.error_location =
			FIELD_GET(RSU_ERROR_LOCATION_MASK, res->a3);
		priv->status.error_details =
			FIELD_GET(RSU_ERROR_DETAIL_MASK, res->a3);
	} else {
		dev_err(client->dev, "COMMAND_RSU_STATUS returned 0x%lX\n",
			res->a0);
		priv->status.version = 0;
		priv->status.state = 0;
		priv->status.fail_image = 0;
		priv->status.current_image = 0;
		priv->status.error_location = 0;
		priv->status.error_details = 0;
	}

	complete(&priv->completion);
}

/**
 * rsu_command_callback() - Update callback from Intel Service Layer
 * @client: pointer to client
 * @data: pointer to callback data structure
 *
 * Callback from Intel service layer for RSU commands.
 */
static void rsu_command_callback(struct stratix10_svc_client *client,
				 struct stratix10_svc_cb_data *data)
{
	struct stratix10_rsu_priv *priv = client->priv;

	if (data->status == BIT(SVC_STATUS_RSU_NO_SUPPORT))
		dev_warn(client->dev, "Secure FW doesn't support notify\n");
	else if (data->status == BIT(SVC_STATUS_RSU_ERROR))
		dev_err(client->dev, "Failure, returned status is %lu\n",
			BIT(data->status));

	complete(&priv->completion);
}

/**
 * rsu_retry_callback() - Callback from Intel service layer for getting
 * the current image's retry counter from firmware
 * @client: pointer to client
 * @data: pointer to callback data structure
 *
 * Callback from Intel service layer for retry counter, which is used by
 * user to know how many times the images is still allowed to reload
 * itself before giving up and starting RSU fail-over flow.
 */
static void rsu_retry_callback(struct stratix10_svc_client *client,
			       struct stratix10_svc_cb_data *data)
{
	struct stratix10_rsu_priv *priv = client->priv;
	unsigned int *counter = (unsigned int *)data->kaddr1;

	if (data->status == BIT(SVC_STATUS_RSU_OK))
		priv->retry_counter = *counter;
	else if (data->status == BIT(SVC_STATUS_RSU_NO_SUPPORT))
		dev_warn(client->dev, "Secure FW doesn't support retry\n");
	else
		dev_err(client->dev, "Failed to get retry counter %lu\n",
			BIT(data->status));

	complete(&priv->completion);
}

/**
 * rsu_send_msg() - send a message to Intel service layer
 * @priv: pointer to rsu private data
 * @command: RSU status or update command
 * @arg: the request argument, the bitstream address or notify status
 * @callback: function pointer for the callback (status or update)
 *
 * Start an Intel service layer transaction to perform the SMC call that
 * is necessary to get RSU boot log or set the address of bitstream to
 * boot after reboot.
 *
 * Returns 0 on success or -ETIMEDOUT on error.
 */
static int rsu_send_msg(struct stratix10_rsu_priv *priv,
			enum stratix10_svc_command_code command,
			unsigned long arg,
			rsu_callback callback)
{
	struct stratix10_svc_client_msg msg;
	int ret;

	mutex_lock(&priv->lock);
	reinit_completion(&priv->completion);
	priv->client.receive_cb = callback;

	msg.command = command;
	if (arg)
		msg.arg[0] = arg;

	ret = stratix10_svc_send(priv->chan, &msg);
	if (ret < 0)
		goto status_done;

	ret = wait_for_completion_interruptible_timeout(&priv->completion,
							RSU_TIMEOUT);
	if (!ret) {
		dev_err(priv->client.dev,
			"timeout waiting for SMC call\n");
		ret = -ETIMEDOUT;
		goto status_done;
	} else if (ret < 0) {
		dev_err(priv->client.dev,
			"error %d waiting for SMC call\n", ret);
		goto status_done;
	} else {
		ret = 0;
	}

status_done:
	stratix10_svc_done(priv->chan);
	mutex_unlock(&priv->lock);
	return ret;
}

/*
 * This driver exposes some optional features of the Intel Stratix 10 SoC FPGA.
 * The sysfs interfaces exposed here are FPGA Remote System Update (RSU)
 * related. They allow user space software to query the configuration system
 * status and to request optional reboot behavior specific to Intel FPGAs.
 */

static ssize_t current_image_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	struct stratix10_rsu_priv *priv = dev_get_drvdata(dev);

	if (!priv)
		return -ENODEV;

	return sprintf(buf, "0x%08lx\n", priv->status.current_image);
}

static ssize_t fail_image_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	struct stratix10_rsu_priv *priv = dev_get_drvdata(dev);

	if (!priv)
		return -ENODEV;

	return sprintf(buf, "0x%08lx\n", priv->status.fail_image);
}

static ssize_t version_show(struct device *dev, struct device_attribute *attr,
			    char *buf)
{
	struct stratix10_rsu_priv *priv = dev_get_drvdata(dev);

	if (!priv)
		return -ENODEV;

	return sprintf(buf, "0x%08x\n", priv->status.version);
}

static ssize_t state_show(struct device *dev, struct device_attribute *attr,
			  char *buf)
{
	struct stratix10_rsu_priv *priv = dev_get_drvdata(dev);

	if (!priv)
		return -ENODEV;

	return sprintf(buf, "0x%08x\n", priv->status.state);
}

static ssize_t error_location_show(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	struct stratix10_rsu_priv *priv = dev_get_drvdata(dev);

	if (!priv)
		return -ENODEV;

	return sprintf(buf, "0x%08x\n", priv->status.error_location);
}

static ssize_t error_details_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	struct stratix10_rsu_priv *priv = dev_get_drvdata(dev);

	if (!priv)
		return -ENODEV;

	return sprintf(buf, "0x%08x\n", priv->status.error_details);
}

static ssize_t retry_counter_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	struct stratix10_rsu_priv *priv = dev_get_drvdata(dev);

	if (!priv)
		return -ENODEV;

	return sprintf(buf, "0x%08x\n", priv->retry_counter);
}

static ssize_t reboot_image_store(struct device *dev,
				  struct device_attribute *attr,
				  const char *buf, size_t count)
{
	struct stratix10_rsu_priv *priv = dev_get_drvdata(dev);
	unsigned long address;
	int ret;

	if (priv == 0)
		return -ENODEV;

	ret = kstrtoul(buf, 0, &address);
	if (ret)
		return ret;

	ret = rsu_send_msg(priv, COMMAND_RSU_UPDATE,
			   address, rsu_command_callback);
	if (ret) {
		dev_err(dev, "Error, RSU update returned %i\n", ret);
		return ret;
	}

	return count;
}

static ssize_t notify_store(struct device *dev,
			    struct device_attribute *attr,
			    const char *buf, size_t count)
{
	struct stratix10_rsu_priv *priv = dev_get_drvdata(dev);
	unsigned long status;
	int ret;

	if (priv == 0)
		return -ENODEV;

	ret = kstrtoul(buf, 0, &status);
	if (ret)
		return ret;

	ret = rsu_send_msg(priv, COMMAND_RSU_NOTIFY,
			   status, rsu_command_callback);
	if (ret) {
		dev_err(dev, "Error, RSU notify returned %i\n", ret);
		return ret;
	}

	/* to get the updated state */
	ret = rsu_send_msg(priv, COMMAND_RSU_STATUS,
			   0, rsu_status_callback);
	if (ret) {
		dev_err(dev, "Error, getting RSU status %i\n", ret);
		return ret;
	}

	ret = rsu_send_msg(priv, COMMAND_RSU_RETRY, 0, rsu_retry_callback);
	if (ret) {
		dev_err(dev, "Error, getting RSU retry %i\n", ret);
		return ret;
	}

	return count;
}

static DEVICE_ATTR_RO(current_image);
static DEVICE_ATTR_RO(fail_image);
static DEVICE_ATTR_RO(state);
static DEVICE_ATTR_RO(version);
static DEVICE_ATTR_RO(error_location);
static DEVICE_ATTR_RO(error_details);
static DEVICE_ATTR_RO(retry_counter);
static DEVICE_ATTR_WO(reboot_image);
static DEVICE_ATTR_WO(notify);

static struct attribute *rsu_attrs[] = {
	&dev_attr_current_image.attr,
	&dev_attr_fail_image.attr,
	&dev_attr_state.attr,
	&dev_attr_version.attr,
	&dev_attr_error_location.attr,
	&dev_attr_error_details.attr,
	&dev_attr_retry_counter.attr,
	&dev_attr_reboot_image.attr,
	&dev_attr_notify.attr,
	NULL
};

ATTRIBUTE_GROUPS(rsu);

static int stratix10_rsu_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct stratix10_rsu_priv *priv;
	int ret;

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->client.dev = dev;
	priv->client.receive_cb = NULL;
	priv->client.priv = priv;
	priv->status.current_image = 0;
	priv->status.fail_image = 0;
	priv->status.error_location = 0;
	priv->status.error_details = 0;
	priv->status.version = 0;
	priv->status.state = 0;
	priv->retry_counter = INVALID_RETRY_COUNTER;

	mutex_init(&priv->lock);
	priv->chan = stratix10_svc_request_channel_byname(&priv->client,
							  SVC_CLIENT_RSU);
	if (IS_ERR(priv->chan)) {
		dev_err(dev, "couldn't get service channel %s\n",
			SVC_CLIENT_RSU);
		return PTR_ERR(priv->chan);
	}

	init_completion(&priv->completion);
	platform_set_drvdata(pdev, priv);

	/* get the initial state from firmware */
	ret = rsu_send_msg(priv, COMMAND_RSU_STATUS,
			   0, rsu_status_callback);
	if (ret) {
		dev_err(dev, "Error, getting RSU status %i\n", ret);
		stratix10_svc_free_channel(priv->chan);
	}

	ret = rsu_send_msg(priv, COMMAND_RSU_RETRY, 0, rsu_retry_callback);
	if (ret) {
		dev_err(dev, "Error, getting RSU retry %i\n", ret);
		stratix10_svc_free_channel(priv->chan);
	}

	return ret;
}

static int stratix10_rsu_remove(struct platform_device *pdev)
{
	struct stratix10_rsu_priv *priv = platform_get_drvdata(pdev);

	stratix10_svc_free_channel(priv->chan);
	return 0;
}

static struct platform_driver stratix10_rsu_driver = {
	.probe = stratix10_rsu_probe,
	.remove = stratix10_rsu_remove,
	.driver = {
		.name = "stratix10-rsu",
		.dev_groups = rsu_groups,
	},
};

module_platform_driver(stratix10_rsu_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Intel Remote System Update Driver");
MODULE_AUTHOR("Richard Gong <richard.gong@intel.com>");