// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2021-2022, Intel Corporation. */

#include "ice.h"
#include "ice_lib.h"

/**
 * ice_gnss_do_write - Write data to internal GNSS receiver
 * @pf: board private structure
 * @buf: command buffer
 * @size: command buffer size
 *
 * Write UBX command data to the GNSS receiver
 *
 * Return:
 * * number of bytes written - success
 * * negative - error code
 */
static int
ice_gnss_do_write(struct ice_pf *pf, const unsigned char *buf, unsigned int size)
{
        struct ice_aqc_link_topo_addr link_topo;
        struct ice_hw *hw = &pf->hw;
        unsigned int offset = 0;
        int err = 0;

        memset(&link_topo, 0, sizeof(struct ice_aqc_link_topo_addr));
        link_topo.topo_params.index = ICE_E810T_GNSS_I2C_BUS;
        link_topo.topo_params.node_type_ctx |=
                FIELD_PREP(ICE_AQC_LINK_TOPO_NODE_CTX_M,
                           ICE_AQC_LINK_TOPO_NODE_CTX_OVERRIDE);

        /* It's not possible to write a single byte to u-blox.
         * Write all bytes in a loop until there are 6 or less bytes left. If
         * there are exactly 6 bytes left, the last write would be only a byte.
         * In this case, do 4+2 bytes writes instead of 5+1. Otherwise, do the
         * last 2 to 5 bytes write.
         */
        while (size - offset > ICE_GNSS_UBX_WRITE_BYTES + 1) {
                err = ice_aq_write_i2c(hw, link_topo, ICE_GNSS_UBX_I2C_BUS_ADDR,
                                       cpu_to_le16(buf[offset]),
                                       ICE_MAX_I2C_WRITE_BYTES,
                                       &buf[offset + 1], NULL);
                if (err)
                        goto err_out;

                offset += ICE_GNSS_UBX_WRITE_BYTES;
        }

        /* Single byte would be written. Write 4 bytes instead of 5. */
        if (size - offset == ICE_GNSS_UBX_WRITE_BYTES + 1) {
                err = ice_aq_write_i2c(hw, link_topo, ICE_GNSS_UBX_I2C_BUS_ADDR,
                                       cpu_to_le16(buf[offset]),
                                       ICE_MAX_I2C_WRITE_BYTES - 1,
                                       &buf[offset + 1], NULL);
                if (err)
                        goto err_out;

                offset += ICE_GNSS_UBX_WRITE_BYTES - 1;
        }

        /* Do the last write, 2 to 5 bytes. */
        err = ice_aq_write_i2c(hw, link_topo, ICE_GNSS_UBX_I2C_BUS_ADDR,
                               cpu_to_le16(buf[offset]), size - offset - 1,
                               &buf[offset + 1], NULL);
        if (err)
                goto err_out;

        return size;

err_out:
        dev_err(ice_pf_to_dev(pf), "GNSS failed to write, offset=%u, size=%u, err=%d\n",
                offset, size, err);

        return err;
}

/**
 * ice_gnss_read - Read data from internal GNSS module
 * @work: GNSS read work structure
 *
 * Read the data from internal GNSS receiver, write it to gnss_dev.
 */
static void ice_gnss_read(struct kthread_work *work)
{
        struct gnss_serial *gnss = container_of(work, struct gnss_serial,
                                                read_work.work);
        unsigned long delay = ICE_GNSS_POLL_DATA_DELAY_TIME;
        unsigned int i, bytes_read, data_len, count;
        struct ice_aqc_link_topo_addr link_topo;
        struct ice_pf *pf;
        struct ice_hw *hw;
        __be16 data_len_b;
        char *buf = NULL;
        u8 i2c_params;
        int err = 0;

        pf = gnss->back;
        if (!pf || !test_bit(ICE_FLAG_GNSS, pf->flags))
                return;

        hw = &pf->hw;

        memset(&link_topo, 0, sizeof(struct ice_aqc_link_topo_addr));
        link_topo.topo_params.index = ICE_E810T_GNSS_I2C_BUS;
        link_topo.topo_params.node_type_ctx |=
                FIELD_PREP(ICE_AQC_LINK_TOPO_NODE_CTX_M,
                           ICE_AQC_LINK_TOPO_NODE_CTX_OVERRIDE);

        i2c_params = ICE_GNSS_UBX_DATA_LEN_WIDTH |
                     ICE_AQC_I2C_USE_REPEATED_START;

        err = ice_aq_read_i2c(hw, link_topo, ICE_GNSS_UBX_I2C_BUS_ADDR,
                              cpu_to_le16(ICE_GNSS_UBX_DATA_LEN_H),
                              i2c_params, (u8 *)&data_len_b, NULL);
        if (err)
                goto requeue;

        data_len = be16_to_cpu(data_len_b);
        if (data_len == 0 || data_len == U16_MAX)
                goto requeue;

        /* The u-blox has data_len bytes for us to read */

        data_len = min_t(typeof(data_len), data_len, PAGE_SIZE);

        buf = (char *)get_zeroed_page(GFP_KERNEL);
        if (!buf) {
                err = -ENOMEM;
                goto requeue;
        }

        /* Read received data */
        for (i = 0; i < data_len; i += bytes_read) {
                unsigned int bytes_left = data_len - i;

                bytes_read = min_t(typeof(bytes_left), bytes_left,
                                   ICE_MAX_I2C_DATA_SIZE);

                err = ice_aq_read_i2c(hw, link_topo, ICE_GNSS_UBX_I2C_BUS_ADDR,
                                      cpu_to_le16(ICE_GNSS_UBX_EMPTY_DATA),
                                      bytes_read, &buf[i], NULL);
                if (err)
                        goto free_buf;
        }

        count = gnss_insert_raw(pf->gnss_dev, buf, i);
        if (count != i)
                dev_warn(ice_pf_to_dev(pf),
                         "gnss_insert_raw ret=%d size=%d\n",
                         count, i);
        delay = ICE_GNSS_TIMER_DELAY_TIME;
free_buf:
        free_page((unsigned long)buf);
requeue:
        kthread_queue_delayed_work(gnss->kworker, &gnss->read_work, delay);
        if (err)
                dev_dbg(ice_pf_to_dev(pf), "GNSS failed to read err=%d\n", err);
}

/**
 * ice_gnss_struct_init - Initialize GNSS receiver
 * @pf: Board private structure
 *
 * Initialize GNSS structures and workers.
 *
 * Return:
 * * pointer to initialized gnss_serial struct - success
 * * NULL - error
 */
static struct gnss_serial *ice_gnss_struct_init(struct ice_pf *pf)
{
        struct device *dev = ice_pf_to_dev(pf);
        struct kthread_worker *kworker;
        struct gnss_serial *gnss;

        gnss = kzalloc_obj(*gnss);
        if (!gnss)
                return NULL;

        gnss->back = pf;
        pf->gnss_serial = gnss;

        kthread_init_delayed_work(&gnss->read_work, ice_gnss_read);
        kworker = kthread_run_worker(0, "ice-gnss-%s", dev_name(dev));
        if (IS_ERR(kworker)) {
                kfree(gnss);
                return NULL;
        }

        gnss->kworker = kworker;

        return gnss;
}

/**
 * ice_gnss_open - Open GNSS device
 * @gdev: pointer to the gnss device struct
 *
 * Open GNSS device and start filling the read buffer for consumer.
 *
 * Return:
 * * 0 - success
 * * negative - error code
 */
static int ice_gnss_open(struct gnss_device *gdev)
{
        struct ice_pf *pf = gnss_get_drvdata(gdev);
        struct gnss_serial *gnss;

        if (!pf)
                return -EFAULT;

        if (!test_bit(ICE_FLAG_GNSS, pf->flags))
                return -EFAULT;

        gnss = pf->gnss_serial;
        if (!gnss)
                return -ENODEV;

        kthread_queue_delayed_work(gnss->kworker, &gnss->read_work, 0);

        return 0;
}

/**
 * ice_gnss_close - Close GNSS device
 * @gdev: pointer to the gnss device struct
 *
 * Close GNSS device, cancel worker, stop filling the read buffer.
 */
static void ice_gnss_close(struct gnss_device *gdev)
{
        struct ice_pf *pf = gnss_get_drvdata(gdev);
        struct gnss_serial *gnss;

        if (!pf)
                return;

        gnss = pf->gnss_serial;
        if (!gnss)
                return;

        kthread_cancel_delayed_work_sync(&gnss->read_work);
}

/**
 * ice_gnss_write - Write to GNSS device
 * @gdev: pointer to the gnss device struct
 * @buf: pointer to the user data
 * @count: size of the buffer to be sent to the GNSS device
 *
 * Return:
 * * number of written bytes - success
 * * negative - error code
 */
static int
ice_gnss_write(struct gnss_device *gdev, const unsigned char *buf,
               size_t count)
{
        struct ice_pf *pf = gnss_get_drvdata(gdev);
        struct gnss_serial *gnss;

        /* We cannot write a single byte using our I2C implementation. */
        if (count <= 1 || count > ICE_GNSS_TTY_WRITE_BUF)
                return -EINVAL;

        if (!pf)
                return -EFAULT;

        if (!test_bit(ICE_FLAG_GNSS, pf->flags))
                return -EFAULT;

        gnss = pf->gnss_serial;
        if (!gnss)
                return -ENODEV;

        return ice_gnss_do_write(pf, buf, count);
}

static const struct gnss_operations ice_gnss_ops = {
        .open = ice_gnss_open,
        .close = ice_gnss_close,
        .write_raw = ice_gnss_write,
};

/**
 * ice_gnss_register - Register GNSS receiver
 * @pf: Board private structure
 *
 * Allocate and register GNSS receiver in the Linux GNSS subsystem.
 *
 * Return:
 * * 0 - success
 * * negative - error code
 */
static int ice_gnss_register(struct ice_pf *pf)
{
        struct gnss_device *gdev;
        int ret;

        gdev = gnss_allocate_device(ice_pf_to_dev(pf));
        if (!gdev) {
                dev_err(ice_pf_to_dev(pf),
                        "gnss_allocate_device returns NULL\n");
                return -ENOMEM;
        }

        gdev->ops = &ice_gnss_ops;
        gdev->type = GNSS_TYPE_UBX;
        gnss_set_drvdata(gdev, pf);
        ret = gnss_register_device(gdev);
        if (ret) {
                dev_err(ice_pf_to_dev(pf), "gnss_register_device err=%d\n",
                        ret);
                gnss_put_device(gdev);
        } else {
                pf->gnss_dev = gdev;
        }

        return ret;
}

/**
 * ice_gnss_deregister - Deregister GNSS receiver
 * @pf: Board private structure
 *
 * Deregister GNSS receiver from the Linux GNSS subsystem,
 * release its resources.
 */
static void ice_gnss_deregister(struct ice_pf *pf)
{
        if (pf->gnss_dev) {
                gnss_deregister_device(pf->gnss_dev);
                gnss_put_device(pf->gnss_dev);
                pf->gnss_dev = NULL;
        }
}

/**
 * ice_gnss_init - Initialize GNSS support
 * @pf: Board private structure
 */
void ice_gnss_init(struct ice_pf *pf)
{
        int ret;

        pf->gnss_serial = ice_gnss_struct_init(pf);
        if (!pf->gnss_serial)
                return;

        ret = ice_gnss_register(pf);
        if (!ret) {
                set_bit(ICE_FLAG_GNSS, pf->flags);
                dev_info(ice_pf_to_dev(pf), "GNSS init successful\n");
        } else {
                ice_gnss_exit(pf);
                dev_err(ice_pf_to_dev(pf), "GNSS init failure\n");
        }
}

/**
 * ice_gnss_exit - Disable GNSS TTY support
 * @pf: Board private structure
 */
void ice_gnss_exit(struct ice_pf *pf)
{
        ice_gnss_deregister(pf);
        clear_bit(ICE_FLAG_GNSS, pf->flags);

        if (pf->gnss_serial) {
                struct gnss_serial *gnss = pf->gnss_serial;

                kthread_cancel_delayed_work_sync(&gnss->read_work);
                kthread_destroy_worker(gnss->kworker);
                gnss->kworker = NULL;

                kfree(gnss);
                pf->gnss_serial = NULL;
        }
}

/**
 * ice_gnss_is_module_present - Check if GNSS HW is present
 * @hw: pointer to HW struct
 *
 * Return: true when GNSS is present, false otherwise.
 */
bool ice_gnss_is_module_present(struct ice_hw *hw)
{
        int err;
        u8 data;

        if (!hw->func_caps.ts_func_info.src_tmr_owned ||
            !ice_is_gps_in_netlist(hw))
                return false;

        err = ice_read_pca9575_reg(hw, ICE_PCA9575_P0_IN, &data);
        if (err || !!(data & ICE_P0_GNSS_PRSNT_N))
                return false;

        return true;
}