// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2012 - 2018 Microchip Technology Inc., and its subsidiaries.
 * All rights reserved.
 */

#include <linux/clk.h>
#include <linux/spi/spi.h>
#include <linux/crc7.h>
#include <linux/crc-itu-t.h>
#include <linux/gpio/consumer.h>

#include "netdev.h"
#include "cfg80211.h"

#define SPI_MODALIAS            "wilc1000_spi"

static bool enable_crc7;        /* protect SPI commands with CRC7 */
module_param(enable_crc7, bool, 0644);
MODULE_PARM_DESC(enable_crc7,
                 "Enable CRC7 checksum to protect command transfers\n"
                 "\t\t\tagainst corruption during the SPI transfer.\n"
                 "\t\t\tCommand transfers are short and the CPU-cycle cost\n"
                 "\t\t\tof enabling this is small.");

static bool enable_crc16;       /* protect SPI data with CRC16 */
module_param(enable_crc16, bool, 0644);
MODULE_PARM_DESC(enable_crc16,
                 "Enable CRC16 checksum to protect data transfers\n"
                 "\t\t\tagainst corruption during the SPI transfer.\n"
                 "\t\t\tData transfers can be large and the CPU-cycle cost\n"
                 "\t\t\tof enabling this may be substantial.");

/*
 * For CMD_SINGLE_READ and CMD_INTERNAL_READ, WILC may insert one or
 * more zero bytes between the command response and the DATA Start tag
 * (0xf3).  This behavior appears to be undocumented in "ATWILC1000
 * USER GUIDE" (https://tinyurl.com/4hhshdts) but we have observed 1-4
 * zero bytes when the SPI bus operates at 48MHz and none when it
 * operates at 1MHz.
 */
#define WILC_SPI_RSP_HDR_EXTRA_DATA     8

struct wilc_spi {
        bool isinit;            /* true if wilc_spi_init was successful */
        bool probing_crc;       /* true if we're probing chip's CRC config */
        bool crc7_enabled;      /* true if crc7 is currently enabled */
        bool crc16_enabled;     /* true if crc16 is currently enabled */
        struct wilc_gpios {
                struct gpio_desc *enable;       /* ENABLE GPIO or NULL */
                struct gpio_desc *reset;        /* RESET GPIO or NULL */
        } gpios;
};

static const struct wilc_hif_func wilc_hif_spi;

static int wilc_spi_reset(struct wilc *wilc);
static int wilc_spi_configure_bus_protocol(struct wilc *wilc);
static int wilc_validate_chipid(struct wilc *wilc);

/********************************************
 *
 *      Spi protocol Function
 *
 ********************************************/

#define CMD_DMA_WRITE                           0xc1
#define CMD_DMA_READ                            0xc2
#define CMD_INTERNAL_WRITE                      0xc3
#define CMD_INTERNAL_READ                       0xc4
#define CMD_TERMINATE                           0xc5
#define CMD_REPEAT                              0xc6
#define CMD_DMA_EXT_WRITE                       0xc7
#define CMD_DMA_EXT_READ                        0xc8
#define CMD_SINGLE_WRITE                        0xc9
#define CMD_SINGLE_READ                         0xca
#define CMD_RESET                               0xcf

#define SPI_RETRY_MAX_LIMIT                     10
#define SPI_ENABLE_VMM_RETRY_LIMIT              2

/* SPI response fields (section 11.1.2 in ATWILC1000 User Guide): */
#define RSP_START_FIELD                         GENMASK(7, 4)
#define RSP_TYPE_FIELD                          GENMASK(3, 0)

/* SPI response values for the response fields: */
#define RSP_START_TAG                           0xc
#define RSP_TYPE_FIRST_PACKET                   0x1
#define RSP_TYPE_INNER_PACKET                   0x2
#define RSP_TYPE_LAST_PACKET                    0x3
#define RSP_STATE_NO_ERROR                      0x00

#define PROTOCOL_REG_PKT_SZ_MASK                GENMASK(6, 4)
#define PROTOCOL_REG_CRC16_MASK                 GENMASK(3, 3)
#define PROTOCOL_REG_CRC7_MASK                  GENMASK(2, 2)

/*
 * The SPI data packet size may be any integer power of two in the
 * range from 256 to 8192 bytes.
 */
#define DATA_PKT_LOG_SZ_MIN                     8       /* 256 B */
#define DATA_PKT_LOG_SZ_MAX                     13      /* 8 KiB */

/*
 * Select the data packet size (log2 of number of bytes): Use the
 * maximum data packet size.  We only retransmit complete packets, so
 * there is no benefit from using smaller data packets.
 */
#define DATA_PKT_LOG_SZ                         DATA_PKT_LOG_SZ_MAX
#define DATA_PKT_SZ                             (1 << DATA_PKT_LOG_SZ)

#define WILC_SPI_COMMAND_STAT_SUCCESS           0
#define WILC_GET_RESP_HDR_START(h)              (((h) >> 4) & 0xf)

struct wilc_spi_cmd {
        u8 cmd_type;
        union {
                struct {
                        u8 addr[3];
                        u8 crc[];
                } __packed simple_cmd;
                struct {
                        u8 addr[3];
                        u8 size[2];
                        u8 crc[];
                } __packed dma_cmd;
                struct {
                        u8 addr[3];
                        u8 size[3];
                        u8 crc[];
                } __packed dma_cmd_ext;
                struct {
                        u8 addr[2];
                        __be32 data;
                        u8 crc[];
                } __packed internal_w_cmd;
                struct {
                        u8 addr[3];
                        __be32 data;
                        u8 crc[];
                } __packed w_cmd;
        } u;
} __packed;

struct wilc_spi_read_rsp_data {
        u8 header;
        u8 data[4];
        u8 crc[];
} __packed;

struct wilc_spi_rsp_data {
        u8 rsp_cmd_type;
        u8 status;
        u8 data[];
} __packed;

struct wilc_spi_special_cmd_rsp {
        u8 skip_byte;
        u8 rsp_cmd_type;
        u8 status;
} __packed;

static int wilc_parse_gpios(struct wilc *wilc)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        struct wilc_spi *spi_priv = wilc->bus_data;
        struct wilc_gpios *gpios = &spi_priv->gpios;

        /* get ENABLE pin and deassert it (if it is defined): */
        gpios->enable = devm_gpiod_get_optional(&spi->dev,
                                                "enable", GPIOD_OUT_LOW);
        /* get RESET pin and assert it (if it is defined): */
        if (gpios->enable) {
                /* if enable pin exists, reset must exist as well */
                gpios->reset = devm_gpiod_get(&spi->dev,
                                              "reset", GPIOD_OUT_HIGH);
                if (IS_ERR(gpios->reset)) {
                        dev_err(&spi->dev, "missing reset gpio.\n");
                        return PTR_ERR(gpios->reset);
                }
        } else {
                gpios->reset = devm_gpiod_get_optional(&spi->dev,
                                                       "reset", GPIOD_OUT_HIGH);
        }
        return 0;
}

static void wilc_wlan_power(struct wilc *wilc, bool on)
{
        struct wilc_spi *spi_priv = wilc->bus_data;
        struct wilc_gpios *gpios = &spi_priv->gpios;

        if (on) {
                /* assert ENABLE: */
                gpiod_set_value(gpios->enable, 1);
                mdelay(5);
                /* deassert RESET: */
                gpiod_set_value(gpios->reset, 0);
        } else {
                /* assert RESET: */
                gpiod_set_value(gpios->reset, 1);
                /* deassert ENABLE: */
                gpiod_set_value(gpios->enable, 0);
        }
}

static int wilc_bus_probe(struct spi_device *spi)
{
        struct wilc_spi *spi_priv;
        struct wilc_vif *vif;
        struct wilc *wilc;
        int ret;

        spi_priv = kzalloc_obj(*spi_priv);
        if (!spi_priv)
                return -ENOMEM;

        ret = wilc_cfg80211_init(&wilc, &spi->dev, WILC_HIF_SPI, &wilc_hif_spi);
        if (ret)
                goto free;

        spi_set_drvdata(spi, wilc);
        wilc->dev = &spi->dev;
        wilc->bus_data = spi_priv;
        wilc->dev_irq_num = spi->irq;

        ret = wilc_parse_gpios(wilc);
        if (ret < 0)
                goto netdev_cleanup;

        wilc->rtc_clk = devm_clk_get_optional_enabled(&spi->dev, "rtc");
        if (IS_ERR(wilc->rtc_clk)) {
                ret = PTR_ERR(wilc->rtc_clk);
                goto netdev_cleanup;
        }

        dev_info(&spi->dev, "Selected CRC config: crc7=%s, crc16=%s\n",
                 enable_crc7 ? "on" : "off", enable_crc16 ? "on" : "off");

        /* we need power to configure the bus protocol and to read the chip id: */

        wilc_wlan_power(wilc, true);

        ret = wilc_spi_configure_bus_protocol(wilc);
        if (ret)
                goto power_down;

        ret = wilc_get_chipid(wilc);
        if (ret)
                goto power_down;

        ret = wilc_cfg80211_register(wilc);
        if (ret)
                goto power_down;

        ret = wilc_load_mac_from_nv(wilc);
        if (ret) {
                pr_err("Can not retrieve MAC address from chip\n");
                goto unregister_wiphy;
        }

        wilc_wlan_power(wilc, false);
        vif = wilc_netdev_ifc_init(wilc, "wlan%d", WILC_STATION_MODE,
                                   NL80211_IFTYPE_STATION, false);
        if (IS_ERR(vif)) {
                ret = PTR_ERR(vif);
                goto unregister_wiphy;
        }
        return 0;

unregister_wiphy:
        wiphy_unregister(wilc->wiphy);
power_down:
        wilc_wlan_power(wilc, false);
netdev_cleanup:
        wilc_netdev_cleanup(wilc);
        wiphy_free(wilc->wiphy);
free:
        kfree(spi_priv);
        return ret;
}

static void wilc_bus_remove(struct spi_device *spi)
{
        struct wilc *wilc = spi_get_drvdata(spi);
        struct wilc_spi *spi_priv = wilc->bus_data;

        wilc_netdev_cleanup(wilc);
        wiphy_unregister(wilc->wiphy);
        wiphy_free(wilc->wiphy);
        kfree(spi_priv);
}

static const struct of_device_id wilc_of_match[] = {
        { .compatible = "microchip,wilc1000", },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, wilc_of_match);

static const struct spi_device_id wilc_spi_id[] = {
        { "wilc1000", 0 },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(spi, wilc_spi_id);

static struct spi_driver wilc_spi_driver = {
        .driver = {
                .name = SPI_MODALIAS,
                .of_match_table = wilc_of_match,
        },
        .id_table = wilc_spi_id,
        .probe =  wilc_bus_probe,
        .remove = wilc_bus_remove,
};
module_spi_driver(wilc_spi_driver);
MODULE_DESCRIPTION("Atmel WILC1000 SPI wireless driver");
MODULE_LICENSE("GPL");

static int wilc_spi_tx(struct wilc *wilc, u8 *b, u32 len)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        int ret;
        struct spi_message msg;

        if (len > 0 && b) {
                struct spi_transfer tr = {
                        .tx_buf = b,
                        .len = len,
                        .delay = {
                                .value = 0,
                                .unit = SPI_DELAY_UNIT_USECS
                        },
                };
                char *r_buffer = kzalloc(len, GFP_KERNEL);

                if (!r_buffer)
                        return -ENOMEM;

                tr.rx_buf = r_buffer;
                dev_dbg(&spi->dev, "Request writing %d bytes\n", len);

                memset(&msg, 0, sizeof(msg));
                spi_message_init(&msg);
                spi_message_add_tail(&tr, &msg);

                ret = spi_sync(spi, &msg);
                if (ret < 0)
                        dev_err(&spi->dev, "SPI transaction failed\n");

                kfree(r_buffer);
        } else {
                dev_err(&spi->dev,
                        "can't write data with the following length: %d\n",
                        len);
                ret = -EINVAL;
        }

        return ret;
}

static int wilc_spi_rx(struct wilc *wilc, u8 *rb, u32 rlen)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        int ret;

        if (rlen > 0) {
                struct spi_message msg;
                struct spi_transfer tr = {
                        .rx_buf = rb,
                        .len = rlen,
                        .delay = {
                                .value = 0,
                                .unit = SPI_DELAY_UNIT_USECS
                        },

                };
                char *t_buffer = kzalloc(rlen, GFP_KERNEL);

                if (!t_buffer)
                        return -ENOMEM;

                tr.tx_buf = t_buffer;

                memset(&msg, 0, sizeof(msg));
                spi_message_init(&msg);
                spi_message_add_tail(&tr, &msg);

                ret = spi_sync(spi, &msg);
                if (ret < 0)
                        dev_err(&spi->dev, "SPI transaction failed\n");
                kfree(t_buffer);
        } else {
                dev_err(&spi->dev,
                        "can't read data with the following length: %u\n",
                        rlen);
                ret = -EINVAL;
        }

        return ret;
}

static int wilc_spi_tx_rx(struct wilc *wilc, u8 *wb, u8 *rb, u32 rlen)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        int ret;

        if (rlen > 0) {
                struct spi_message msg;
                struct spi_transfer tr = {
                        .rx_buf = rb,
                        .tx_buf = wb,
                        .len = rlen,
                        .bits_per_word = 8,
                        .delay = {
                                .value = 0,
                                .unit = SPI_DELAY_UNIT_USECS
                        },

                };

                memset(&msg, 0, sizeof(msg));
                spi_message_init(&msg);
                spi_message_add_tail(&tr, &msg);
                ret = spi_sync(spi, &msg);
                if (ret < 0)
                        dev_err(&spi->dev, "SPI transaction failed\n");
        } else {
                dev_err(&spi->dev,
                        "can't read data with the following length: %u\n",
                        rlen);
                ret = -EINVAL;
        }

        return ret;
}

static int spi_data_write(struct wilc *wilc, u8 *b, u32 sz)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        struct wilc_spi *spi_priv = wilc->bus_data;
        int ix, nbytes;
        int result = 0;
        u8 cmd, order, crc[2];
        u16 crc_calc;

        /*
         * Data
         */
        ix = 0;
        do {
                if (sz <= DATA_PKT_SZ) {
                        nbytes = sz;
                        order = 0x3;
                } else {
                        nbytes = DATA_PKT_SZ;
                        if (ix == 0)
                                order = 0x1;
                        else
                                order = 0x02;
                }

                /*
                 * Write command
                 */
                cmd = 0xf0;
                cmd |= order;

                if (wilc_spi_tx(wilc, &cmd, 1)) {
                        dev_err(&spi->dev,
                                "Failed data block cmd write, bus error...\n");
                        result = -EINVAL;
                        break;
                }

                /*
                 * Write data
                 */
                if (wilc_spi_tx(wilc, &b[ix], nbytes)) {
                        dev_err(&spi->dev,
                                "Failed data block write, bus error...\n");
                        result = -EINVAL;
                        break;
                }

                /*
                 * Write CRC
                 */
                if (spi_priv->crc16_enabled) {
                        crc_calc = crc_itu_t(0xffff, &b[ix], nbytes);
                        crc[0] = crc_calc >> 8;
                        crc[1] = crc_calc;
                        if (wilc_spi_tx(wilc, crc, 2)) {
                                dev_err(&spi->dev, "Failed data block crc write, bus error...\n");
                                result = -EINVAL;
                                break;
                        }
                }

                /*
                 * No need to wait for response
                 */
                ix += nbytes;
                sz -= nbytes;
        } while (sz);

        return result;
}

/********************************************
 *
 *      Spi Internal Read/Write Function
 *
 ********************************************/
static u8 wilc_get_crc7(u8 *buffer, u32 len)
{
        return crc7_be(0xfe, buffer, len) | 0x01;
}

static int wilc_spi_single_read(struct wilc *wilc, u8 cmd, u32 adr, void *b,
                                u8 clockless)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        struct wilc_spi *spi_priv = wilc->bus_data;
        u8 wb[32], rb[32];
        int cmd_len, resp_len, i;
        u16 crc_calc, crc_recv;
        struct wilc_spi_cmd *c;
        struct wilc_spi_rsp_data *r;
        struct wilc_spi_read_rsp_data *r_data;

        memset(wb, 0x0, sizeof(wb));
        memset(rb, 0x0, sizeof(rb));
        c = (struct wilc_spi_cmd *)wb;
        c->cmd_type = cmd;
        if (cmd == CMD_SINGLE_READ) {
                c->u.simple_cmd.addr[0] = adr >> 16;
                c->u.simple_cmd.addr[1] = adr >> 8;
                c->u.simple_cmd.addr[2] = adr;
        } else if (cmd == CMD_INTERNAL_READ) {
                c->u.simple_cmd.addr[0] = adr >> 8;
                if (clockless == 1)
                        c->u.simple_cmd.addr[0] |= BIT(7);
                c->u.simple_cmd.addr[1] = adr;
                c->u.simple_cmd.addr[2] = 0x0;
        } else {
                dev_err(&spi->dev, "cmd [%x] not supported\n", cmd);
                return -EINVAL;
        }

        cmd_len = offsetof(struct wilc_spi_cmd, u.simple_cmd.crc);
        resp_len = sizeof(*r) + sizeof(*r_data) + WILC_SPI_RSP_HDR_EXTRA_DATA;

        if (spi_priv->crc7_enabled) {
                c->u.simple_cmd.crc[0] = wilc_get_crc7(wb, cmd_len);
                cmd_len += 1;
                resp_len += 2;
        }

        if (cmd_len + resp_len > ARRAY_SIZE(wb)) {
                dev_err(&spi->dev,
                        "spi buffer size too small (%d) (%d) (%zu)\n",
                        cmd_len, resp_len, ARRAY_SIZE(wb));
                return -EINVAL;
        }

        if (wilc_spi_tx_rx(wilc, wb, rb, cmd_len + resp_len)) {
                dev_err(&spi->dev, "Failed cmd write, bus error...\n");
                return -EINVAL;
        }

        r = (struct wilc_spi_rsp_data *)&rb[cmd_len];
        if (r->rsp_cmd_type != cmd && !clockless) {
                if (!spi_priv->probing_crc)
                        dev_err(&spi->dev,
                                "Failed cmd, cmd (%02x), resp (%02x)\n",
                                cmd, r->rsp_cmd_type);
                return -EINVAL;
        }

        if (r->status != WILC_SPI_COMMAND_STAT_SUCCESS && !clockless) {
                dev_err(&spi->dev, "Failed cmd state response state (%02x)\n",
                        r->status);
                return -EINVAL;
        }

        for (i = 0; i < WILC_SPI_RSP_HDR_EXTRA_DATA; ++i)
                if (WILC_GET_RESP_HDR_START(r->data[i]) == 0xf)
                        break;

        if (i >= WILC_SPI_RSP_HDR_EXTRA_DATA) {
                dev_err(&spi->dev, "Error, data start missing\n");
                return -EINVAL;
        }

        r_data = (struct wilc_spi_read_rsp_data *)&r->data[i];

        if (b)
                memcpy(b, r_data->data, 4);

        if (!clockless && spi_priv->crc16_enabled) {
                crc_recv = (r_data->crc[0] << 8) | r_data->crc[1];
                crc_calc = crc_itu_t(0xffff, r_data->data, 4);
                if (crc_recv != crc_calc) {
                        dev_err(&spi->dev, "%s: bad CRC 0x%04x "
                                "(calculated 0x%04x)\n", __func__,
                                crc_recv, crc_calc);
                        return -EINVAL;
                }
        }

        return 0;
}

static int wilc_spi_write_cmd(struct wilc *wilc, u8 cmd, u32 adr, u32 data,
                              u8 clockless)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        struct wilc_spi *spi_priv = wilc->bus_data;
        u8 wb[32], rb[32];
        int cmd_len, resp_len;
        struct wilc_spi_cmd *c;
        struct wilc_spi_rsp_data *r;

        memset(wb, 0x0, sizeof(wb));
        memset(rb, 0x0, sizeof(rb));
        c = (struct wilc_spi_cmd *)wb;
        c->cmd_type = cmd;
        if (cmd == CMD_INTERNAL_WRITE) {
                c->u.internal_w_cmd.addr[0] = adr >> 8;
                if (clockless == 1)
                        c->u.internal_w_cmd.addr[0] |= BIT(7);

                c->u.internal_w_cmd.addr[1] = adr;
                c->u.internal_w_cmd.data = cpu_to_be32(data);
                cmd_len = offsetof(struct wilc_spi_cmd, u.internal_w_cmd.crc);
                if (spi_priv->crc7_enabled)
                        c->u.internal_w_cmd.crc[0] = wilc_get_crc7(wb, cmd_len);
        } else if (cmd == CMD_SINGLE_WRITE) {
                c->u.w_cmd.addr[0] = adr >> 16;
                c->u.w_cmd.addr[1] = adr >> 8;
                c->u.w_cmd.addr[2] = adr;
                c->u.w_cmd.data = cpu_to_be32(data);
                cmd_len = offsetof(struct wilc_spi_cmd, u.w_cmd.crc);
                if (spi_priv->crc7_enabled)
                        c->u.w_cmd.crc[0] = wilc_get_crc7(wb, cmd_len);
        } else {
                dev_err(&spi->dev, "write cmd [%x] not supported\n", cmd);
                return -EINVAL;
        }

        if (spi_priv->crc7_enabled)
                cmd_len += 1;

        resp_len = sizeof(*r);

        if (cmd_len + resp_len > ARRAY_SIZE(wb)) {
                dev_err(&spi->dev,
                        "spi buffer size too small (%d) (%d) (%zu)\n",
                        cmd_len, resp_len, ARRAY_SIZE(wb));
                return -EINVAL;
        }

        if (wilc_spi_tx_rx(wilc, wb, rb, cmd_len + resp_len)) {
                dev_err(&spi->dev, "Failed cmd write, bus error...\n");
                return -EINVAL;
        }

        r = (struct wilc_spi_rsp_data *)&rb[cmd_len];
        /*
         * Clockless registers operations might return unexptected responses,
         * even if successful.
         */
        if (r->rsp_cmd_type != cmd && !clockless) {
                dev_err(&spi->dev,
                        "Failed cmd response, cmd (%02x), resp (%02x)\n",
                        cmd, r->rsp_cmd_type);
                return -EINVAL;
        }

        if (r->status != WILC_SPI_COMMAND_STAT_SUCCESS && !clockless) {
                dev_err(&spi->dev, "Failed cmd state response state (%02x)\n",
                        r->status);
                return -EINVAL;
        }

        return 0;
}

static int wilc_spi_dma_rw(struct wilc *wilc, u8 cmd, u32 adr, u8 *b, u32 sz)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        struct wilc_spi *spi_priv = wilc->bus_data;
        u16 crc_recv, crc_calc;
        u8 wb[32], rb[32];
        int cmd_len, resp_len;
        int retry, ix = 0;
        u8 crc[2];
        struct wilc_spi_cmd *c;
        struct wilc_spi_rsp_data *r;

        memset(wb, 0x0, sizeof(wb));
        memset(rb, 0x0, sizeof(rb));
        c = (struct wilc_spi_cmd *)wb;
        c->cmd_type = cmd;
        if (cmd == CMD_DMA_WRITE || cmd == CMD_DMA_READ) {
                c->u.dma_cmd.addr[0] = adr >> 16;
                c->u.dma_cmd.addr[1] = adr >> 8;
                c->u.dma_cmd.addr[2] = adr;
                c->u.dma_cmd.size[0] = sz >> 8;
                c->u.dma_cmd.size[1] = sz;
                cmd_len = offsetof(struct wilc_spi_cmd, u.dma_cmd.crc);
                if (spi_priv->crc7_enabled)
                        c->u.dma_cmd.crc[0] = wilc_get_crc7(wb, cmd_len);
        } else if (cmd == CMD_DMA_EXT_WRITE || cmd == CMD_DMA_EXT_READ) {
                c->u.dma_cmd_ext.addr[0] = adr >> 16;
                c->u.dma_cmd_ext.addr[1] = adr >> 8;
                c->u.dma_cmd_ext.addr[2] = adr;
                c->u.dma_cmd_ext.size[0] = sz >> 16;
                c->u.dma_cmd_ext.size[1] = sz >> 8;
                c->u.dma_cmd_ext.size[2] = sz;
                cmd_len = offsetof(struct wilc_spi_cmd, u.dma_cmd_ext.crc);
                if (spi_priv->crc7_enabled)
                        c->u.dma_cmd_ext.crc[0] = wilc_get_crc7(wb, cmd_len);
        } else {
                dev_err(&spi->dev, "dma read write cmd [%x] not supported\n",
                        cmd);
                return -EINVAL;
        }
        if (spi_priv->crc7_enabled)
                cmd_len += 1;

        resp_len = sizeof(*r);

        if (cmd_len + resp_len > ARRAY_SIZE(wb)) {
                dev_err(&spi->dev, "spi buffer size too small (%d)(%d) (%zu)\n",
                        cmd_len, resp_len, ARRAY_SIZE(wb));
                return -EINVAL;
        }

        if (wilc_spi_tx_rx(wilc, wb, rb, cmd_len + resp_len)) {
                dev_err(&spi->dev, "Failed cmd write, bus error...\n");
                return -EINVAL;
        }

        r = (struct wilc_spi_rsp_data *)&rb[cmd_len];
        if (r->rsp_cmd_type != cmd) {
                dev_err(&spi->dev,
                        "Failed cmd response, cmd (%02x), resp (%02x)\n",
                        cmd, r->rsp_cmd_type);
                return -EINVAL;
        }

        if (r->status != WILC_SPI_COMMAND_STAT_SUCCESS) {
                dev_err(&spi->dev, "Failed cmd state response state (%02x)\n",
                        r->status);
                return -EINVAL;
        }

        if (cmd == CMD_DMA_WRITE || cmd == CMD_DMA_EXT_WRITE)
                return 0;

        while (sz > 0) {
                int nbytes;
                u8 rsp;

                nbytes = min_t(u32, sz, DATA_PKT_SZ);

                /*
                 * Data Response header
                 */
                retry = 100;
                do {
                        if (wilc_spi_rx(wilc, &rsp, 1)) {
                                dev_err(&spi->dev,
                                        "Failed resp read, bus err\n");
                                return -EINVAL;
                        }
                        if (WILC_GET_RESP_HDR_START(rsp) == 0xf)
                                break;
                } while (retry--);

                /*
                 * Read bytes
                 */
                if (wilc_spi_rx(wilc, &b[ix], nbytes)) {
                        dev_err(&spi->dev,
                                "Failed block read, bus err\n");
                        return -EINVAL;
                }

                /*
                 * Read CRC
                 */
                if (spi_priv->crc16_enabled) {
                        if (wilc_spi_rx(wilc, crc, 2)) {
                                dev_err(&spi->dev,
                                        "Failed block CRC read, bus err\n");
                                return -EINVAL;
                        }
                        crc_recv = (crc[0] << 8) | crc[1];
                        crc_calc = crc_itu_t(0xffff, &b[ix], nbytes);
                        if (crc_recv != crc_calc) {
                                dev_err(&spi->dev, "%s: bad CRC 0x%04x "
                                        "(calculated 0x%04x)\n", __func__,
                                        crc_recv, crc_calc);
                                return -EINVAL;
                        }
                }

                ix += nbytes;
                sz -= nbytes;
        }
        return 0;
}

static int wilc_spi_special_cmd(struct wilc *wilc, u8 cmd)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        struct wilc_spi *spi_priv = wilc->bus_data;
        u8 wb[32], rb[32];
        int cmd_len, resp_len = 0;
        struct wilc_spi_cmd *c;
        struct wilc_spi_special_cmd_rsp *r;

        if (cmd != CMD_TERMINATE && cmd != CMD_REPEAT && cmd != CMD_RESET)
                return -EINVAL;

        memset(wb, 0x0, sizeof(wb));
        memset(rb, 0x0, sizeof(rb));
        c = (struct wilc_spi_cmd *)wb;
        c->cmd_type = cmd;

        if (cmd == CMD_RESET)
                memset(c->u.simple_cmd.addr, 0xFF, 3);

        cmd_len = offsetof(struct wilc_spi_cmd, u.simple_cmd.crc);
        resp_len = sizeof(*r);

        if (spi_priv->crc7_enabled) {
                c->u.simple_cmd.crc[0] = wilc_get_crc7(wb, cmd_len);
                cmd_len += 1;
        }
        if (cmd_len + resp_len > ARRAY_SIZE(wb)) {
                dev_err(&spi->dev, "spi buffer size too small (%d) (%d) (%zu)\n",
                        cmd_len, resp_len, ARRAY_SIZE(wb));
                return -EINVAL;
        }

        if (wilc_spi_tx_rx(wilc, wb, rb, cmd_len + resp_len)) {
                dev_err(&spi->dev, "Failed cmd write, bus error...\n");
                return -EINVAL;
        }

        r = (struct wilc_spi_special_cmd_rsp *)&rb[cmd_len];
        if (r->rsp_cmd_type != cmd) {
                if (!spi_priv->probing_crc)
                        dev_err(&spi->dev,
                                "Failed cmd response, cmd (%02x), resp (%02x)\n",
                                cmd, r->rsp_cmd_type);
                return -EINVAL;
        }

        if (r->status != WILC_SPI_COMMAND_STAT_SUCCESS) {
                dev_err(&spi->dev, "Failed cmd state response state (%02x)\n",
                        r->status);
                return -EINVAL;
        }
        return 0;
}

static void wilc_spi_reset_cmd_sequence(struct wilc *wl, u8 attempt, u32 addr)
{
        struct spi_device *spi = to_spi_device(wl->dev);
        struct wilc_spi *spi_priv = wl->bus_data;

        if (!spi_priv->probing_crc)
                dev_err(&spi->dev, "Reset and retry %d %x\n", attempt, addr);

        usleep_range(1000, 1100);
        wilc_spi_reset(wl);
        usleep_range(1000, 1100);
}

static int wilc_spi_read_reg(struct wilc *wilc, u32 addr, u32 *data)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        int result;
        u8 cmd = CMD_SINGLE_READ;
        u8 clockless = 0;
        u8 i;

        if (addr <= WILC_SPI_CLOCKLESS_ADDR_LIMIT) {
                /* Clockless register */
                cmd = CMD_INTERNAL_READ;
                clockless = 1;
        }

        for (i = 0; i < SPI_RETRY_MAX_LIMIT; i++) {
                result = wilc_spi_single_read(wilc, cmd, addr, data, clockless);
                if (!result) {
                        le32_to_cpus(data);
                        return 0;
                }

                /* retry is not applicable for clockless registers */
                if (clockless)
                        break;

                dev_err(&spi->dev, "Failed cmd, read reg (%08x)...\n", addr);
                wilc_spi_reset_cmd_sequence(wilc, i, addr);
        }

        return result;
}

static int wilc_spi_read(struct wilc *wilc, u32 addr, u8 *buf, u32 size)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        int result;
        u8 i;

        if (size <= 4)
                return -EINVAL;

        for (i = 0; i < SPI_RETRY_MAX_LIMIT; i++) {
                result = wilc_spi_dma_rw(wilc, CMD_DMA_EXT_READ, addr,
                                         buf, size);
                if (!result)
                        return 0;

                dev_err(&spi->dev, "Failed cmd, read block (%08x)...\n", addr);

                wilc_spi_reset_cmd_sequence(wilc, i, addr);
        }

        return result;
}

static int spi_internal_write(struct wilc *wilc, u32 adr, u32 dat)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        int result;
        u8 i;

        for (i = 0; i < SPI_RETRY_MAX_LIMIT; i++) {
                result = wilc_spi_write_cmd(wilc, CMD_INTERNAL_WRITE, adr,
                                            dat, 0);
                if (!result)
                        return 0;
                dev_err(&spi->dev, "Failed internal write cmd...\n");

                wilc_spi_reset_cmd_sequence(wilc, i, adr);
        }

        return result;
}

static int spi_internal_read(struct wilc *wilc, u32 adr, u32 *data)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        struct wilc_spi *spi_priv = wilc->bus_data;
        int result;
        u8 i;

        for (i = 0; i < SPI_RETRY_MAX_LIMIT; i++) {
                result = wilc_spi_single_read(wilc, CMD_INTERNAL_READ, adr,
                                              data, 0);
                if (!result) {
                        le32_to_cpus(data);
                        return 0;
                }
                if (!spi_priv->probing_crc)
                        dev_err(&spi->dev, "Failed internal read cmd...\n");

                wilc_spi_reset_cmd_sequence(wilc, i, adr);
        }

        return result;
}

/********************************************
 *
 *      Spi interfaces
 *
 ********************************************/

static int wilc_spi_write_reg(struct wilc *wilc, u32 addr, u32 data)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        int result;
        u8 cmd = CMD_SINGLE_WRITE;
        u8 clockless = 0;
        u8 i;

        if (addr <= WILC_SPI_CLOCKLESS_ADDR_LIMIT) {
                /* Clockless register */
                cmd = CMD_INTERNAL_WRITE;
                clockless = 1;
        }

        for (i = 0; i < SPI_RETRY_MAX_LIMIT; i++) {
                result = wilc_spi_write_cmd(wilc, cmd, addr, data, clockless);
                if (!result)
                        return 0;

                dev_err(&spi->dev, "Failed cmd, write reg (%08x)...\n", addr);

                if (clockless)
                        break;

                wilc_spi_reset_cmd_sequence(wilc, i, addr);
        }
        return result;
}

static int spi_data_rsp(struct wilc *wilc, u8 cmd)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        int result, i;
        u8 rsp[4];

        /*
         * The response to data packets is two bytes long.  For
         * efficiency's sake, wilc_spi_write() wisely ignores the
         * responses for all packets but the final one.  The downside
         * of that optimization is that when the final data packet is
         * short, we may receive (part of) the response to the
         * second-to-last packet before the one for the final packet.
         * To handle this, we always read 4 bytes and then search for
         * the last byte that contains the "Response Start" code (0xc
         * in the top 4 bits).  We then know that this byte is the
         * first response byte of the final data packet.
         */
        result = wilc_spi_rx(wilc, rsp, sizeof(rsp));
        if (result) {
                dev_err(&spi->dev, "Failed bus error...\n");
                return result;
        }

        for (i = sizeof(rsp) - 2; i >= 0; --i)
                if (FIELD_GET(RSP_START_FIELD, rsp[i]) == RSP_START_TAG)
                        break;

        if (i < 0) {
                dev_err(&spi->dev,
                        "Data packet response missing (%02x %02x %02x %02x)\n",
                        rsp[0], rsp[1], rsp[2], rsp[3]);
                return -1;
        }

        /* rsp[i] is the last response start byte */

        if (FIELD_GET(RSP_TYPE_FIELD, rsp[i]) != RSP_TYPE_LAST_PACKET
            || rsp[i + 1] != RSP_STATE_NO_ERROR) {
                dev_err(&spi->dev, "Data response error (%02x %02x)\n",
                        rsp[i], rsp[i + 1]);
                return -1;
        }
        return 0;
}

static int wilc_spi_write(struct wilc *wilc, u32 addr, u8 *buf, u32 size)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        int result;
        u8 i;

        /*
         * has to be greated than 4
         */
        if (size <= 4)
                return -EINVAL;

        for (i = 0; i < SPI_RETRY_MAX_LIMIT; i++) {
                result = wilc_spi_dma_rw(wilc, CMD_DMA_EXT_WRITE, addr,
                                         NULL, size);
                if (result) {
                        dev_err(&spi->dev,
                                "Failed cmd, write block (%08x)...\n", addr);
                        wilc_spi_reset_cmd_sequence(wilc, i, addr);
                        continue;
                }

                /*
                 * Data
                 */
                result = spi_data_write(wilc, buf, size);
                if (result) {
                        dev_err(&spi->dev, "Failed block data write...\n");
                        wilc_spi_reset_cmd_sequence(wilc, i, addr);
                        continue;
                }

                /*
                 * Data response
                 */
                result = spi_data_rsp(wilc, CMD_DMA_EXT_WRITE);
                if (result) {
                        dev_err(&spi->dev, "Failed block data rsp...\n");
                        wilc_spi_reset_cmd_sequence(wilc, i, addr);
                        continue;
                }
                break;
        }
        return result;
}

/********************************************
 *
 *      Bus interfaces
 *
 ********************************************/

static int wilc_spi_reset(struct wilc *wilc)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        struct wilc_spi *spi_priv = wilc->bus_data;
        int result;

        result = wilc_spi_special_cmd(wilc, CMD_RESET);
        if (result && !spi_priv->probing_crc)
                dev_err(&spi->dev, "Failed cmd reset\n");

        return result;
}

static bool wilc_spi_is_init(struct wilc *wilc)
{
        struct wilc_spi *spi_priv = wilc->bus_data;

        return spi_priv->isinit;
}

static int wilc_spi_deinit(struct wilc *wilc)
{
        struct wilc_spi *spi_priv = wilc->bus_data;

        spi_priv->isinit = false;
        wilc_wlan_power(wilc, false);
        return 0;
}

static int wilc_spi_init(struct wilc *wilc, bool resume)
{
        struct wilc_spi *spi_priv = wilc->bus_data;
        int ret;

        if (spi_priv->isinit) {
                /* Confirm we can read chipid register without error: */
                if (wilc_validate_chipid(wilc) == 0)
                        return 0;
        }

        wilc_wlan_power(wilc, true);

        ret = wilc_spi_configure_bus_protocol(wilc);
        if (ret) {
                wilc_wlan_power(wilc, false);
                return ret;
        }

        spi_priv->isinit = true;

        return 0;
}

static int wilc_spi_configure_bus_protocol(struct wilc *wilc)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        struct wilc_spi *spi_priv = wilc->bus_data;
        u32 reg;
        int ret, i;

        /*
         * Infer the CRC settings that are currently in effect.  This
         * is necessary because we can't be sure that the chip has
         * been RESET (e.g, after module unload and reload).
         */
        spi_priv->probing_crc = true;
        spi_priv->crc7_enabled = enable_crc7;
        spi_priv->crc16_enabled = false; /* don't check CRC16 during probing */
        for (i = 0; i < 2; ++i) {
                ret = spi_internal_read(wilc, WILC_SPI_PROTOCOL_OFFSET, &reg);
                if (ret == 0)
                        break;
                spi_priv->crc7_enabled = !enable_crc7;
        }
        if (ret) {
                dev_err(&spi->dev, "Failed with CRC7 on and off.\n");
                return ret;
        }

        /* set up the desired CRC configuration: */
        reg &= ~(PROTOCOL_REG_CRC7_MASK | PROTOCOL_REG_CRC16_MASK);
        if (enable_crc7)
                reg |= PROTOCOL_REG_CRC7_MASK;
        if (enable_crc16)
                reg |= PROTOCOL_REG_CRC16_MASK;

        /* set up the data packet size: */
        BUILD_BUG_ON(DATA_PKT_LOG_SZ < DATA_PKT_LOG_SZ_MIN
                     || DATA_PKT_LOG_SZ > DATA_PKT_LOG_SZ_MAX);
        reg &= ~PROTOCOL_REG_PKT_SZ_MASK;
        reg |= FIELD_PREP(PROTOCOL_REG_PKT_SZ_MASK,
                          DATA_PKT_LOG_SZ - DATA_PKT_LOG_SZ_MIN);

        /* establish the new setup: */
        ret = spi_internal_write(wilc, WILC_SPI_PROTOCOL_OFFSET, reg);
        if (ret) {
                dev_err(&spi->dev,
                        "[wilc spi %d]: Failed internal write reg\n",
                        __LINE__);
                return ret;
        }
        /* update our state to match new protocol settings: */
        spi_priv->crc7_enabled = enable_crc7;
        spi_priv->crc16_enabled = enable_crc16;

        /* re-read to make sure new settings are in effect: */
        spi_internal_read(wilc, WILC_SPI_PROTOCOL_OFFSET, &reg);

        spi_priv->probing_crc = false;

        return 0;
}

static int wilc_validate_chipid(struct wilc *wilc)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        u32 chipid;
        int ret;

        /*
         * make sure can read chip id without protocol error
         */
        ret = wilc_spi_read_reg(wilc, WILC_CHIPID, &chipid);
        if (ret) {
                dev_err(&spi->dev, "Fail cmd read chip id...\n");
                return ret;
        }
        if (!is_wilc1000(chipid) && !is_wilc3000(chipid)) {
                dev_err(&spi->dev, "Unknown chip id 0x%x\n", chipid);
                return -ENODEV;
        }
        return 0;
}

static int wilc_spi_read_size(struct wilc *wilc, u32 *size)
{
        int ret;

        ret = spi_internal_read(wilc,
                                WILC_SPI_INT_STATUS - WILC_SPI_REG_BASE, size);
        *size = FIELD_GET(IRQ_DMA_WD_CNT_MASK, *size);

        return ret;
}

static int wilc_spi_read_int(struct wilc *wilc, u32 *int_status)
{
        return spi_internal_read(wilc, WILC_SPI_INT_STATUS - WILC_SPI_REG_BASE,
                                 int_status);
}

static int wilc_spi_clear_int_ext(struct wilc *wilc, u32 val)
{
        int ret;
        int retry = SPI_ENABLE_VMM_RETRY_LIMIT;
        u32 check;

        while (retry) {
                ret = spi_internal_write(wilc,
                                         WILC_SPI_INT_CLEAR - WILC_SPI_REG_BASE,
                                         val);
                if (ret)
                        break;

                ret = spi_internal_read(wilc,
                                        WILC_SPI_INT_CLEAR - WILC_SPI_REG_BASE,
                                        &check);
                if (ret || ((check & EN_VMM) == (val & EN_VMM)))
                        break;

                retry--;
        }
        return ret;
}

static int wilc_spi_sync_ext(struct wilc *wilc, int nint)
{
        struct spi_device *spi = to_spi_device(wilc->dev);
        u32 reg;
        int ret, i;

        if (nint > MAX_NUM_INT) {
                dev_err(&spi->dev, "Too many interrupts (%d)...\n", nint);
                return -EINVAL;
        }

        /*
         * interrupt pin mux select
         */
        ret = wilc_spi_read_reg(wilc, WILC_PIN_MUX_0, &reg);
        if (ret) {
                dev_err(&spi->dev, "Failed read reg (%08x)...\n",
                        WILC_PIN_MUX_0);
                return ret;
        }
        reg |= BIT(8);
        ret = wilc_spi_write_reg(wilc, WILC_PIN_MUX_0, reg);
        if (ret) {
                dev_err(&spi->dev, "Failed write reg (%08x)...\n",
                        WILC_PIN_MUX_0);
                return ret;
        }

        /*
         * interrupt enable
         */
        ret = wilc_spi_read_reg(wilc, WILC_INTR_ENABLE, &reg);
        if (ret) {
                dev_err(&spi->dev, "Failed read reg (%08x)...\n",
                        WILC_INTR_ENABLE);
                return ret;
        }

        for (i = 0; (i < 5) && (nint > 0); i++, nint--)
                reg |= (BIT((27 + i)));

        ret = wilc_spi_write_reg(wilc, WILC_INTR_ENABLE, reg);
        if (ret) {
                dev_err(&spi->dev, "Failed write reg (%08x)...\n",
                        WILC_INTR_ENABLE);
                return ret;
        }
        if (nint) {
                ret = wilc_spi_read_reg(wilc, WILC_INTR2_ENABLE, &reg);
                if (ret) {
                        dev_err(&spi->dev, "Failed read reg (%08x)...\n",
                                WILC_INTR2_ENABLE);
                        return ret;
                }

                for (i = 0; (i < 3) && (nint > 0); i++, nint--)
                        reg |= BIT(i);

                ret = wilc_spi_write_reg(wilc, WILC_INTR2_ENABLE, reg);
                if (ret) {
                        dev_err(&spi->dev, "Failed write reg (%08x)...\n",
                                WILC_INTR2_ENABLE);
                        return ret;
                }
        }

        return 0;
}

/* Global spi HIF function table */
static const struct wilc_hif_func wilc_hif_spi = {
        .hif_init = wilc_spi_init,
        .hif_deinit = wilc_spi_deinit,
        .hif_read_reg = wilc_spi_read_reg,
        .hif_write_reg = wilc_spi_write_reg,
        .hif_block_rx = wilc_spi_read,
        .hif_block_tx = wilc_spi_write,
        .hif_read_int = wilc_spi_read_int,
        .hif_clear_int_ext = wilc_spi_clear_int_ext,
        .hif_read_size = wilc_spi_read_size,
        .hif_block_tx_ext = wilc_spi_write,
        .hif_block_rx_ext = wilc_spi_read,
        .hif_sync_ext = wilc_spi_sync_ext,
        .hif_reset = wilc_spi_reset,
        .hif_is_init = wilc_spi_is_init,
};