// 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_FW_VERSION_MASK             GENMASK_ULL(15, 0)

#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_OK))
                dev_err(client->dev, "RSU returned status is %i\n",
                        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
                dev_err(client->dev, "Failed to get retry counter %i\n",
                        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;
        }

        /* only 19.3 or late version FW supports retry counter feature */
        if (FIELD_GET(RSU_FW_VERSION_MASK, priv->status.version)) {
                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);
        }

        /* only 19.3 or late version FW supports retry counter feature */
        if (FIELD_GET(RSU_FW_VERSION_MASK, priv->status.version)) {
                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>");