// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2008-2010
 *
 * - Kurt Van Dijck, EIA Electronics
 */

#include <linux/firmware.h>
#include <linux/sched/signal.h>
#include <asm/div64.h>
#include <asm/io.h>

#include "softing.h"

/*
 * low level DPRAM command.
 * Make sure that card->dpram[DPRAM_FCT_HOST] is preset
 */
static int _softing_fct_cmd(struct softing *card, int16_t cmd, uint16_t vector,
                const char *msg)
{
        int ret;
        unsigned long stamp;

        iowrite16(cmd, &card->dpram[DPRAM_FCT_PARAM]);
        iowrite8(vector >> 8, &card->dpram[DPRAM_FCT_HOST + 1]);
        iowrite8(vector, &card->dpram[DPRAM_FCT_HOST]);
        /* be sure to flush this to the card */
        wmb();
        stamp = jiffies + 1 * HZ;
        /* wait for card */
        do {
                /* DPRAM_FCT_HOST is _not_ aligned */
                ret = ioread8(&card->dpram[DPRAM_FCT_HOST]) +
                        (ioread8(&card->dpram[DPRAM_FCT_HOST + 1]) << 8);
                /* don't have any cached variables */
                rmb();
                if (ret == RES_OK)
                        /* read return-value now */
                        return ioread16(&card->dpram[DPRAM_FCT_RESULT]);

                if ((ret != vector) || time_after(jiffies, stamp))
                        break;
                /* process context => relax */
                usleep_range(500, 10000);
        } while (1);

        ret = (ret == RES_NONE) ? -ETIMEDOUT : -ECANCELED;
        dev_alert(&card->pdev->dev, "firmware %s failed (%i)\n", msg, ret);
        return ret;
}

static int softing_fct_cmd(struct softing *card, int16_t cmd, const char *msg)
{
        int ret;

        ret = _softing_fct_cmd(card, cmd, 0, msg);
        if (ret > 0) {
                dev_alert(&card->pdev->dev, "%s returned %u\n", msg, ret);
                ret = -EIO;
        }
        return ret;
}

int softing_bootloader_command(struct softing *card, int16_t cmd,
                const char *msg)
{
        int ret;
        unsigned long stamp;

        iowrite16(RES_NONE, &card->dpram[DPRAM_RECEIPT]);
        iowrite16(cmd, &card->dpram[DPRAM_COMMAND]);
        /* be sure to flush this to the card */
        wmb();
        stamp = jiffies + 3 * HZ;
        /* wait for card */
        do {
                ret = ioread16(&card->dpram[DPRAM_RECEIPT]);
                /* don't have any cached variables */
                rmb();
                if (ret == RES_OK)
                        return 0;
                if (time_after(jiffies, stamp))
                        break;
                /* process context => relax */
                usleep_range(500, 10000);
        } while (!signal_pending(current));

        ret = (ret == RES_NONE) ? -ETIMEDOUT : -ECANCELED;
        dev_alert(&card->pdev->dev, "bootloader %s failed (%i)\n", msg, ret);
        return ret;
}

static int fw_parse(const uint8_t **pmem, uint16_t *ptype, uint32_t *paddr,
                uint16_t *plen, const uint8_t **pdat)
{
        uint16_t checksum[2];
        const uint8_t *mem;
        const uint8_t *end;

        /*
         * firmware records are a binary, unaligned stream composed of:
         * uint16_t type;
         * uint32_t addr;
         * uint16_t len;
         * uint8_t dat[len];
         * uint16_t checksum;
         * all values in little endian.
         * We could define a struct for this, with __attribute__((packed)),
         * but would that solve the alignment in _all_ cases (cfr. the
         * struct itself may be an odd address)?
         *
         * I chose to use leXX_to_cpup() since this solves both
         * endianness & alignment.
         */
        mem = *pmem;
        *ptype = le16_to_cpup((void *)&mem[0]);
        *paddr = le32_to_cpup((void *)&mem[2]);
        *plen = le16_to_cpup((void *)&mem[6]);
        *pdat = &mem[8];
        /* verify checksum */
        end = &mem[8 + *plen];
        checksum[0] = le16_to_cpup((void *)end);
        for (checksum[1] = 0; mem < end; ++mem)
                checksum[1] += *mem;
        if (checksum[0] != checksum[1])
                return -EINVAL;
        /* increment */
        *pmem += 10 + *plen;
        return 0;
}

int softing_load_fw(const char *file, struct softing *card,
                __iomem uint8_t *dpram, unsigned int size, int offset)
{
        const struct firmware *fw;
        int ret;
        const uint8_t *mem, *end, *dat;
        uint16_t type, len;
        uint32_t addr;
        uint8_t *buf = NULL, *new_buf;
        int buflen = 0;
        int8_t type_end = 0;

        ret = request_firmware(&fw, file, &card->pdev->dev);
        if (ret < 0)
                return ret;
        dev_dbg(&card->pdev->dev, "%s, firmware(%s) got %u bytes"
                ", offset %c0x%04x\n",
                card->pdat->name, file, (unsigned int)fw->size,
                (offset >= 0) ? '+' : '-', (unsigned int)abs(offset));
        /* parse the firmware */
        mem = fw->data;
        end = &mem[fw->size];
        /* look for header record */
        ret = fw_parse(&mem, &type, &addr, &len, &dat);
        if (ret < 0)
                goto failed;
        if (type != 0xffff)
                goto failed;
        if (strncmp("Structured Binary Format, Softing GmbH" , dat, len)) {
                ret = -EINVAL;
                goto failed;
        }
        /* ok, we had a header */
        while (mem < end) {
                ret = fw_parse(&mem, &type, &addr, &len, &dat);
                if (ret < 0)
                        goto failed;
                if (type == 3) {
                        /* start address, not used here */
                        continue;
                } else if (type == 1) {
                        /* eof */
                        type_end = 1;
                        break;
                } else if (type != 0) {
                        ret = -EINVAL;
                        goto failed;
                }

                if ((addr + len + offset) > size)
                        goto failed;
                memcpy_toio(&dpram[addr + offset], dat, len);
                /* be sure to flush caches from IO space */
                mb();
                if (len > buflen) {
                        /* align buflen */
                        buflen = (len + (1024-1)) & ~(1024-1);
                        new_buf = krealloc(buf, buflen, GFP_KERNEL);
                        if (!new_buf) {
                                ret = -ENOMEM;
                                goto failed;
                        }
                        buf = new_buf;
                }
                /* verify record data */
                memcpy_fromio(buf, &dpram[addr + offset], len);
                if (memcmp(buf, dat, len)) {
                        /* is not ok */
                        dev_alert(&card->pdev->dev, "DPRAM readback failed\n");
                        ret = -EIO;
                        goto failed;
                }
        }
        if (!type_end)
                /* no end record seen */
                goto failed;
        ret = 0;
failed:
        kfree(buf);
        release_firmware(fw);
        if (ret < 0)
                dev_info(&card->pdev->dev, "firmware %s failed\n", file);
        return ret;
}

int softing_load_app_fw(const char *file, struct softing *card)
{
        const struct firmware *fw;
        const uint8_t *mem, *end, *dat;
        int ret, j;
        uint16_t type, len;
        uint32_t addr, start_addr = 0;
        unsigned int sum, rx_sum;
        int8_t type_end = 0, type_entrypoint = 0;

        ret = request_firmware(&fw, file, &card->pdev->dev);
        if (ret) {
                dev_alert(&card->pdev->dev, "request_firmware(%s) got %i\n",
                        file, ret);
                return ret;
        }
        dev_dbg(&card->pdev->dev, "firmware(%s) got %lu bytes\n",
                file, (unsigned long)fw->size);
        /* parse the firmware */
        mem = fw->data;
        end = &mem[fw->size];
        /* look for header record */
        ret = fw_parse(&mem, &type, &addr, &len, &dat);
        if (ret)
                goto failed;
        ret = -EINVAL;
        if (type != 0xffff) {
                dev_alert(&card->pdev->dev, "firmware starts with type 0x%x\n",
                        type);
                goto failed;
        }
        if (strncmp("Structured Binary Format, Softing GmbH", dat, len)) {
                dev_alert(&card->pdev->dev, "firmware string '%.*s' fault\n",
                                len, dat);
                goto failed;
        }
        /* ok, we had a header */
        while (mem < end) {
                ret = fw_parse(&mem, &type, &addr, &len, &dat);
                if (ret)
                        goto failed;

                if (type == 3) {
                        /* start address */
                        start_addr = addr;
                        type_entrypoint = 1;
                        continue;
                } else if (type == 1) {
                        /* eof */
                        type_end = 1;
                        break;
                } else if (type != 0) {
                        dev_alert(&card->pdev->dev,
                                        "unknown record type 0x%04x\n", type);
                        ret = -EINVAL;
                        goto failed;
                }

                /* regular data */
                for (sum = 0, j = 0; j < len; ++j)
                        sum += dat[j];
                /* work in 16bit (target) */
                sum &= 0xffff;

                memcpy_toio(&card->dpram[card->pdat->app.offs], dat, len);
                iowrite32(card->pdat->app.offs + card->pdat->app.addr,
                                &card->dpram[DPRAM_COMMAND + 2]);
                iowrite32(addr, &card->dpram[DPRAM_COMMAND + 6]);
                iowrite16(len, &card->dpram[DPRAM_COMMAND + 10]);
                iowrite8(1, &card->dpram[DPRAM_COMMAND + 12]);
                ret = softing_bootloader_command(card, 1, "loading app.");
                if (ret < 0)
                        goto failed;
                /* verify checksum */
                rx_sum = ioread16(&card->dpram[DPRAM_RECEIPT + 2]);
                if (rx_sum != sum) {
                        dev_alert(&card->pdev->dev, "SRAM seems to be damaged"
                                ", wanted 0x%04x, got 0x%04x\n", sum, rx_sum);
                        ret = -EIO;
                        goto failed;
                }
        }
        if (!type_end || !type_entrypoint)
                goto failed;
        /* start application in card */
        iowrite32(start_addr, &card->dpram[DPRAM_COMMAND + 2]);
        iowrite8(1, &card->dpram[DPRAM_COMMAND + 6]);
        ret = softing_bootloader_command(card, 3, "start app.");
        if (ret < 0)
                goto failed;
        ret = 0;
failed:
        release_firmware(fw);
        if (ret < 0)
                dev_info(&card->pdev->dev, "firmware %s failed\n", file);
        return ret;
}

static int softing_reset_chip(struct softing *card)
{
        int ret;

        do {
                /* reset chip */
                iowrite8(0, &card->dpram[DPRAM_RESET_RX_FIFO]);
                iowrite8(0, &card->dpram[DPRAM_RESET_RX_FIFO+1]);
                iowrite8(1, &card->dpram[DPRAM_RESET]);
                iowrite8(0, &card->dpram[DPRAM_RESET+1]);

                ret = softing_fct_cmd(card, 0, "reset_can");
                if (!ret)
                        break;
                if (signal_pending(current))
                        /* don't wait any longer */
                        break;
        } while (1);
        card->tx.pending = 0;
        return ret;
}

int softing_chip_poweron(struct softing *card)
{
        int ret;
        /* sync */
        ret = _softing_fct_cmd(card, 99, 0x55, "sync-a");
        if (ret < 0)
                goto failed;

        ret = _softing_fct_cmd(card, 99, 0xaa, "sync-b");
        if (ret < 0)
                goto failed;

        ret = softing_reset_chip(card);
        if (ret < 0)
                goto failed;
        /* get_serial */
        ret = softing_fct_cmd(card, 43, "get_serial_number");
        if (ret < 0)
                goto failed;
        card->id.serial = ioread32(&card->dpram[DPRAM_FCT_PARAM]);
        /* get_version */
        ret = softing_fct_cmd(card, 12, "get_version");
        if (ret < 0)
                goto failed;
        card->id.fw_version = ioread16(&card->dpram[DPRAM_FCT_PARAM + 2]);
        card->id.hw_version = ioread16(&card->dpram[DPRAM_FCT_PARAM + 4]);
        card->id.license = ioread16(&card->dpram[DPRAM_FCT_PARAM + 6]);
        card->id.chip[0] = ioread16(&card->dpram[DPRAM_FCT_PARAM + 8]);
        card->id.chip[1] = ioread16(&card->dpram[DPRAM_FCT_PARAM + 10]);
        return 0;
failed:
        return ret;
}

static void softing_initialize_timestamp(struct softing *card)
{
        uint64_t ovf;

        card->ts_ref = ktime_get();

        /* 16MHz is the reference */
        ovf = 0x100000000ULL * 16;
        do_div(ovf, card->pdat->freq ?: 16);

        card->ts_overflow = ktime_add_us(0, ovf);
}

ktime_t softing_raw2ktime(struct softing *card, u32 raw)
{
        uint64_t rawl;
        ktime_t now, real_offset;
        ktime_t target;
        ktime_t tmp;

        now = ktime_get();
        real_offset = ktime_sub(ktime_get_real(), now);

        /* find nsec from card */
        rawl = raw * 16;
        do_div(rawl, card->pdat->freq ?: 16);
        target = ktime_add_us(card->ts_ref, rawl);
        /* test for overflows */
        tmp = ktime_add(target, card->ts_overflow);
        while (unlikely(ktime_to_ns(tmp) > ktime_to_ns(now))) {
                card->ts_ref = ktime_add(card->ts_ref, card->ts_overflow);
                target = tmp;
                tmp = ktime_add(target, card->ts_overflow);
        }
        return ktime_add(target, real_offset);
}

static inline int softing_error_reporting(struct net_device *netdev)
{
        struct softing_priv *priv = netdev_priv(netdev);

        return (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
                ? 1 : 0;
}

int softing_startstop(struct net_device *dev, int up)
{
        int ret;
        struct softing *card;
        struct softing_priv *priv;
        struct net_device *netdev;
        int bus_bitmask_start;
        int j, error_reporting;
        struct can_frame msg;
        const struct can_bittiming *bt;

        priv = netdev_priv(dev);
        card = priv->card;

        if (!card->fw.up)
                return -EIO;

        ret = mutex_lock_interruptible(&card->fw.lock);
        if (ret)
                return ret;

        bus_bitmask_start = 0;
        if (up)
                /* prepare to start this bus as well */
                bus_bitmask_start |= (1 << priv->index);
        /* bring netdevs down */
        for (j = 0; j < ARRAY_SIZE(card->net); ++j) {
                netdev = card->net[j];
                if (!netdev)
                        continue;
                priv = netdev_priv(netdev);

                if (dev != netdev)
                        netif_stop_queue(netdev);

                if (netif_running(netdev)) {
                        if (dev != netdev)
                                bus_bitmask_start |= (1 << j);
                        priv->tx.pending = 0;
                        priv->tx.echo_put = 0;
                        priv->tx.echo_get = 0;
                        /*
                         * this bus' may just have called open_candev()
                         * which is rather stupid to call close_candev()
                         * already
                         * but we may come here from busoff recovery too
                         * in which case the echo_skb _needs_ flushing too.
                         * just be sure to call open_candev() again
                         */
                        close_candev(netdev);
                }
                priv->can.state = CAN_STATE_STOPPED;
        }
        card->tx.pending = 0;

        softing_enable_irq(card, 0);
        ret = softing_reset_chip(card);
        if (ret)
                goto failed;
        if (!bus_bitmask_start)
                /* no buses to be brought up */
                goto card_done;

        if ((bus_bitmask_start & 1) && (bus_bitmask_start & 2)
                        && (softing_error_reporting(card->net[0])
                                != softing_error_reporting(card->net[1]))) {
                dev_alert(&card->pdev->dev,
                                "err_reporting flag differs for buses\n");
                goto invalid;
        }
        error_reporting = 0;
        if (bus_bitmask_start & 1) {
                netdev = card->net[0];
                priv = netdev_priv(netdev);
                error_reporting += softing_error_reporting(netdev);
                /* init chip 1 */
                bt = &priv->can.bittiming;
                iowrite16(bt->brp, &card->dpram[DPRAM_FCT_PARAM + 2]);
                iowrite16(bt->sjw, &card->dpram[DPRAM_FCT_PARAM + 4]);
                iowrite16(bt->phase_seg1 + bt->prop_seg,
                                &card->dpram[DPRAM_FCT_PARAM + 6]);
                iowrite16(bt->phase_seg2, &card->dpram[DPRAM_FCT_PARAM + 8]);
                iowrite16((priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES) ? 1 : 0,
                                &card->dpram[DPRAM_FCT_PARAM + 10]);
                ret = softing_fct_cmd(card, 1, "initialize_chip[0]");
                if (ret < 0)
                        goto failed;
                /* set mode */
                iowrite16(0, &card->dpram[DPRAM_FCT_PARAM + 2]);
                iowrite16(0, &card->dpram[DPRAM_FCT_PARAM + 4]);
                ret = softing_fct_cmd(card, 3, "set_mode[0]");
                if (ret < 0)
                        goto failed;
                /* set filter */
                /* 11bit id & mask */
                iowrite16(0x0000, &card->dpram[DPRAM_FCT_PARAM + 2]);
                iowrite16(0x07ff, &card->dpram[DPRAM_FCT_PARAM + 4]);
                /* 29bit id.lo & mask.lo & id.hi & mask.hi */
                iowrite16(0x0000, &card->dpram[DPRAM_FCT_PARAM + 6]);
                iowrite16(0xffff, &card->dpram[DPRAM_FCT_PARAM + 8]);
                iowrite16(0x0000, &card->dpram[DPRAM_FCT_PARAM + 10]);
                iowrite16(0x1fff, &card->dpram[DPRAM_FCT_PARAM + 12]);
                ret = softing_fct_cmd(card, 7, "set_filter[0]");
                if (ret < 0)
                        goto failed;
                /* set output control */
                iowrite16(priv->output, &card->dpram[DPRAM_FCT_PARAM + 2]);
                ret = softing_fct_cmd(card, 5, "set_output[0]");
                if (ret < 0)
                        goto failed;
        }
        if (bus_bitmask_start & 2) {
                netdev = card->net[1];
                priv = netdev_priv(netdev);
                error_reporting += softing_error_reporting(netdev);
                /* init chip2 */
                bt = &priv->can.bittiming;
                iowrite16(bt->brp, &card->dpram[DPRAM_FCT_PARAM + 2]);
                iowrite16(bt->sjw, &card->dpram[DPRAM_FCT_PARAM + 4]);
                iowrite16(bt->phase_seg1 + bt->prop_seg,
                                &card->dpram[DPRAM_FCT_PARAM + 6]);
                iowrite16(bt->phase_seg2, &card->dpram[DPRAM_FCT_PARAM + 8]);
                iowrite16((priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES) ? 1 : 0,
                                &card->dpram[DPRAM_FCT_PARAM + 10]);
                ret = softing_fct_cmd(card, 2, "initialize_chip[1]");
                if (ret < 0)
                        goto failed;
                /* set mode2 */
                iowrite16(0, &card->dpram[DPRAM_FCT_PARAM + 2]);
                iowrite16(0, &card->dpram[DPRAM_FCT_PARAM + 4]);
                ret = softing_fct_cmd(card, 4, "set_mode[1]");
                if (ret < 0)
                        goto failed;
                /* set filter2 */
                /* 11bit id & mask */
                iowrite16(0x0000, &card->dpram[DPRAM_FCT_PARAM + 2]);
                iowrite16(0x07ff, &card->dpram[DPRAM_FCT_PARAM + 4]);
                /* 29bit id.lo & mask.lo & id.hi & mask.hi */
                iowrite16(0x0000, &card->dpram[DPRAM_FCT_PARAM + 6]);
                iowrite16(0xffff, &card->dpram[DPRAM_FCT_PARAM + 8]);
                iowrite16(0x0000, &card->dpram[DPRAM_FCT_PARAM + 10]);
                iowrite16(0x1fff, &card->dpram[DPRAM_FCT_PARAM + 12]);
                ret = softing_fct_cmd(card, 8, "set_filter[1]");
                if (ret < 0)
                        goto failed;
                /* set output control2 */
                iowrite16(priv->output, &card->dpram[DPRAM_FCT_PARAM + 2]);
                ret = softing_fct_cmd(card, 6, "set_output[1]");
                if (ret < 0)
                        goto failed;
        }

        /* enable_error_frame
         *
         * Error reporting is switched off at the moment since
         * the receiving of them is not yet 100% verified
         * This should be enabled sooner or later
         */
        if (0 && error_reporting) {
                ret = softing_fct_cmd(card, 51, "enable_error_frame");
                if (ret < 0)
                        goto failed;
        }

        /* initialize interface */
        iowrite16(1, &card->dpram[DPRAM_FCT_PARAM + 2]);
        iowrite16(1, &card->dpram[DPRAM_FCT_PARAM + 4]);
        iowrite16(1, &card->dpram[DPRAM_FCT_PARAM + 6]);
        iowrite16(1, &card->dpram[DPRAM_FCT_PARAM + 8]);
        iowrite16(1, &card->dpram[DPRAM_FCT_PARAM + 10]);
        iowrite16(1, &card->dpram[DPRAM_FCT_PARAM + 12]);
        iowrite16(1, &card->dpram[DPRAM_FCT_PARAM + 14]);
        iowrite16(1, &card->dpram[DPRAM_FCT_PARAM + 16]);
        iowrite16(1, &card->dpram[DPRAM_FCT_PARAM + 18]);
        iowrite16(1, &card->dpram[DPRAM_FCT_PARAM + 20]);
        ret = softing_fct_cmd(card, 17, "initialize_interface");
        if (ret < 0)
                goto failed;
        /* enable_fifo */
        ret = softing_fct_cmd(card, 36, "enable_fifo");
        if (ret < 0)
                goto failed;
        /* enable fifo tx ack */
        ret = softing_fct_cmd(card, 13, "fifo_tx_ack[0]");
        if (ret < 0)
                goto failed;
        /* enable fifo tx ack2 */
        ret = softing_fct_cmd(card, 14, "fifo_tx_ack[1]");
        if (ret < 0)
                goto failed;
        /* start_chip */
        ret = softing_fct_cmd(card, 11, "start_chip");
        if (ret < 0)
                goto failed;
        iowrite8(0, &card->dpram[DPRAM_INFO_BUSSTATE]);
        iowrite8(0, &card->dpram[DPRAM_INFO_BUSSTATE2]);
        if (card->pdat->generation < 2) {
                iowrite8(0, &card->dpram[DPRAM_V2_IRQ_TOHOST]);
                /* flush the DPRAM caches */
                wmb();
        }

        softing_initialize_timestamp(card);

        /*
         * do socketcan notifications/status changes
         * from here, no errors should occur, or the failed: part
         * must be reviewed
         */
        memset(&msg, 0, sizeof(msg));
        msg.can_id = CAN_ERR_FLAG | CAN_ERR_RESTARTED;
        msg.len = CAN_ERR_DLC;
        for (j = 0; j < ARRAY_SIZE(card->net); ++j) {
                if (!(bus_bitmask_start & (1 << j)))
                        continue;
                netdev = card->net[j];
                if (!netdev)
                        continue;
                priv = netdev_priv(netdev);
                priv->can.state = CAN_STATE_ERROR_ACTIVE;
                open_candev(netdev);
                if (dev != netdev) {
                        /* notify other buses on the restart */
                        softing_netdev_rx(netdev, &msg, 0);
                        ++priv->can.can_stats.restarts;
                }
                netif_wake_queue(netdev);
        }

        /* enable interrupts */
        ret = softing_enable_irq(card, 1);
        if (ret)
                goto failed;
card_done:
        mutex_unlock(&card->fw.lock);
        return 0;
invalid:
        ret = -EINVAL;
failed:
        softing_enable_irq(card, 0);
        softing_reset_chip(card);
        mutex_unlock(&card->fw.lock);
        /* bring all other interfaces down */
        for (j = 0; j < ARRAY_SIZE(card->net); ++j) {
                netdev = card->net[j];
                if (!netdev)
                        continue;
                dev_close(netdev);
        }
        return ret;
}

int softing_default_output(struct net_device *netdev)
{
        struct softing_priv *priv = netdev_priv(netdev);
        struct softing *card = priv->card;

        switch (priv->chip) {
        case 1000:
                return (card->pdat->generation < 2) ? 0xfb : 0xfa;
        case 5:
                return 0x60;
        default:
                return 0x40;
        }
}