// SPDX-License-Identifier: GPL-2.0
/*
 * Driver for FPGA Accelerated Function Unit (AFU) Error Reporting
 *
 * Copyright 2019 Intel Corporation, Inc.
 *
 * Authors:
 *   Wu Hao <hao.wu@linux.intel.com>
 *   Xiao Guangrong <guangrong.xiao@linux.intel.com>
 *   Joseph Grecco <joe.grecco@intel.com>
 *   Enno Luebbers <enno.luebbers@intel.com>
 *   Tim Whisonant <tim.whisonant@intel.com>
 *   Ananda Ravuri <ananda.ravuri@intel.com>
 *   Mitchel Henry <henry.mitchel@intel.com>
 */

#include <linux/fpga-dfl.h>
#include <linux/uaccess.h>

#include "dfl-afu.h"

#define PORT_ERROR_MASK         0x8
#define PORT_ERROR              0x10
#define PORT_FIRST_ERROR        0x18
#define PORT_MALFORMED_REQ0     0x20
#define PORT_MALFORMED_REQ1     0x28

#define ERROR_MASK              GENMASK_ULL(63, 0)

/* mask or unmask port errors by the error mask register. */
static void __afu_port_err_mask(struct dfl_feature_dev_data *fdata, bool mask)
{
        void __iomem *base;

        base = dfl_get_feature_ioaddr_by_id(fdata, PORT_FEATURE_ID_ERROR);

        writeq(mask ? ERROR_MASK : 0, base + PORT_ERROR_MASK);
}

static void afu_port_err_mask(struct device *dev, bool mask)
{
        struct dfl_feature_dev_data *fdata = to_dfl_feature_dev_data(dev);

        mutex_lock(&fdata->lock);
        __afu_port_err_mask(fdata, mask);
        mutex_unlock(&fdata->lock);
}

/* clear port errors. */
static int afu_port_err_clear(struct device *dev, u64 err)
{
        struct dfl_feature_dev_data *fdata = to_dfl_feature_dev_data(dev);
        void __iomem *base_err, *base_hdr;
        int enable_ret = 0, ret = -EBUSY;
        u64 v;

        base_err = dfl_get_feature_ioaddr_by_id(fdata, PORT_FEATURE_ID_ERROR);
        base_hdr = dfl_get_feature_ioaddr_by_id(fdata, PORT_FEATURE_ID_HEADER);

        mutex_lock(&fdata->lock);

        /*
         * clear Port Errors
         *
         * - Check for AP6 State
         * - Halt Port by keeping Port in reset
         * - Set PORT Error mask to all 1 to mask errors
         * - Clear all errors
         * - Set Port mask to all 0 to enable errors
         * - All errors start capturing new errors
         * - Enable Port by pulling the port out of reset
         */

        /* if device is still in AP6 power state, can not clear any error. */
        v = readq(base_hdr + PORT_HDR_STS);
        if (FIELD_GET(PORT_STS_PWR_STATE, v) == PORT_STS_PWR_STATE_AP6) {
                dev_err(dev, "Could not clear errors, device in AP6 state.\n");
                goto done;
        }

        /* Halt Port by keeping Port in reset */
        ret = __afu_port_disable(fdata);
        if (ret)
                goto done;

        /* Mask all errors */
        __afu_port_err_mask(fdata, true);

        /* Clear errors if err input matches with current port errors.*/
        v = readq(base_err + PORT_ERROR);

        if (v == err) {
                writeq(v, base_err + PORT_ERROR);

                v = readq(base_err + PORT_FIRST_ERROR);
                writeq(v, base_err + PORT_FIRST_ERROR);
        } else {
                dev_warn(dev, "%s: received 0x%llx, expected 0x%llx\n",
                         __func__, v, err);
                ret = -EINVAL;
        }

        /* Clear mask */
        __afu_port_err_mask(fdata, false);

        /* Enable the Port by clearing the reset */
        enable_ret = __afu_port_enable(fdata);

done:
        mutex_unlock(&fdata->lock);
        return enable_ret ? enable_ret : ret;
}

static ssize_t errors_show(struct device *dev, struct device_attribute *attr,
                           char *buf)
{
        struct dfl_feature_dev_data *fdata = to_dfl_feature_dev_data(dev);
        void __iomem *base;
        u64 error;

        base = dfl_get_feature_ioaddr_by_id(fdata, PORT_FEATURE_ID_ERROR);

        mutex_lock(&fdata->lock);
        error = readq(base + PORT_ERROR);
        mutex_unlock(&fdata->lock);

        return sprintf(buf, "0x%llx\n", (unsigned long long)error);
}

static ssize_t errors_store(struct device *dev, struct device_attribute *attr,
                            const char *buff, size_t count)
{
        u64 value;
        int ret;

        if (kstrtou64(buff, 0, &value))
                return -EINVAL;

        ret = afu_port_err_clear(dev, value);

        return ret ? ret : count;
}
static DEVICE_ATTR_RW(errors);

static ssize_t first_error_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct dfl_feature_dev_data *fdata = to_dfl_feature_dev_data(dev);
        void __iomem *base;
        u64 error;

        base = dfl_get_feature_ioaddr_by_id(fdata, PORT_FEATURE_ID_ERROR);

        mutex_lock(&fdata->lock);
        error = readq(base + PORT_FIRST_ERROR);
        mutex_unlock(&fdata->lock);

        return sprintf(buf, "0x%llx\n", (unsigned long long)error);
}
static DEVICE_ATTR_RO(first_error);

static ssize_t first_malformed_req_show(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf)
{
        struct dfl_feature_dev_data *fdata = to_dfl_feature_dev_data(dev);
        void __iomem *base;
        u64 req0, req1;

        base = dfl_get_feature_ioaddr_by_id(fdata, PORT_FEATURE_ID_ERROR);

        mutex_lock(&fdata->lock);
        req0 = readq(base + PORT_MALFORMED_REQ0);
        req1 = readq(base + PORT_MALFORMED_REQ1);
        mutex_unlock(&fdata->lock);

        return sprintf(buf, "0x%016llx%016llx\n",
                       (unsigned long long)req1, (unsigned long long)req0);
}
static DEVICE_ATTR_RO(first_malformed_req);

static struct attribute *port_err_attrs[] = {
        &dev_attr_errors.attr,
        &dev_attr_first_error.attr,
        &dev_attr_first_malformed_req.attr,
        NULL,
};

static umode_t port_err_attrs_visible(struct kobject *kobj,
                                      struct attribute *attr, int n)
{
        struct device *dev = kobj_to_dev(kobj);
        struct dfl_feature_dev_data *fdata;

        fdata = to_dfl_feature_dev_data(dev);
        /*
         * sysfs entries are visible only if related private feature is
         * enumerated.
         */
        if (!dfl_get_feature_by_id(fdata, PORT_FEATURE_ID_ERROR))
                return 0;

        return attr->mode;
}

const struct attribute_group port_err_group = {
        .name       = "errors",
        .attrs      = port_err_attrs,
        .is_visible = port_err_attrs_visible,
};

static int port_err_init(struct platform_device *pdev,
                         struct dfl_feature *feature)
{
        afu_port_err_mask(&pdev->dev, false);

        return 0;
}

static void port_err_uinit(struct platform_device *pdev,
                           struct dfl_feature *feature)
{
        afu_port_err_mask(&pdev->dev, true);
}

static long
port_err_ioctl(struct platform_device *pdev, struct dfl_feature *feature,
               unsigned int cmd, unsigned long arg)
{
        switch (cmd) {
        case DFL_FPGA_PORT_ERR_GET_IRQ_NUM:
                return dfl_feature_ioctl_get_num_irqs(pdev, feature, arg);
        case DFL_FPGA_PORT_ERR_SET_IRQ:
                return dfl_feature_ioctl_set_irq(pdev, feature, arg);
        default:
                dev_dbg(&pdev->dev, "%x cmd not handled", cmd);
                return -ENODEV;
        }
}

const struct dfl_feature_id port_err_id_table[] = {
        {.id = PORT_FEATURE_ID_ERROR,},
        {0,}
};

const struct dfl_feature_ops port_err_ops = {
        .init = port_err_init,
        .uinit = port_err_uinit,
        .ioctl = port_err_ioctl,
};