// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Driver for Spase SP8870 demodulator
.*
 *  Copyright (C) 1999 Juergen Peitz
 */

/*
 * This driver needs external firmware. Please use the command
 * "<kerneldir>/scripts/get_dvb_firmware alps_tdlb7" to
 * download/extract it, and then copy it to /usr/lib/hotplug/firmware
 * or /lib/firmware (depending on configuration of firmware hotplug).
 */

#ifdef pr_fmt
#undef pr_fmt
#endif
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#define SP8870_DEFAULT_FIRMWARE "dvb-fe-sp8870.fw"

#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/firmware.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/slab.h>

#include <media/dvb_frontend.h>
#include "sp8870.h"

struct sp8870_state {
        struct i2c_adapter *i2c;

        const struct sp8870_config *config;

        struct dvb_frontend frontend;

        /* demodulator private data */
        u8 initialised:1;
};

static int debug;
#define dprintk(fmt, arg...) \
        do { \
                if (debug) \
                        pr_info("%s(): " fmt, __func__, ##arg); \
        } while (0)

/* firmware size for sp8870 */
#define SP8870_FIRMWARE_SIZE 16382

/* starting point for firmware in file 'Sc_main.mc' */
#define SP8870_FIRMWARE_OFFSET 0x0A

static int sp8870_writereg(struct sp8870_state *state, u16 reg, u16 data)
{
        u8 buf[] = { reg >> 8, reg & 0xff, data >> 8, data & 0xff };
        struct i2c_msg msg = {
                .addr = state->config->demod_address,
                .flags = 0,
                .buf = buf,
                .len = 4
        };

        int err;

        err = i2c_transfer(state->i2c, &msg, 1);
        if (err != 1) {
                dprintk("writereg error (err == %i, reg == 0x%02x, data == 0x%02x)\n", err, reg, data);
                return -EREMOTEIO;
        }

        return 0;
}

static int sp8870_readreg(struct sp8870_state *state, u16 reg)
{
        int ret;
        u8 b0[] = { reg >> 8, reg & 0xff };
        u8 b1[] = { 0, 0 };
        struct i2c_msg msg[] = {
                { .addr = state->config->demod_address, .flags = 0, .buf = b0, .len = 2 },
                { .addr = state->config->demod_address, .flags = I2C_M_RD, .buf = b1, .len = 2 }
        };

        ret = i2c_transfer(state->i2c, msg, 2);

        if (ret != 2) {
                dprintk("readreg error (ret == %i)\n", ret);
                return -1;
        }

        return (b1[0] << 8 | b1[1]);
}

static int sp8870_firmware_upload(struct sp8870_state *state, const struct firmware *fw)
{
        struct i2c_msg msg;
        const char *fw_buf = fw->data;
        int fw_pos;
        u8 tx_buf[255];
        int tx_len;
        int err = 0;

        dprintk("start firmware upload...\n");

        if (fw->size < SP8870_FIRMWARE_SIZE + SP8870_FIRMWARE_OFFSET)
                return -EINVAL;

        // system controller stop
        sp8870_writereg(state, 0x0F00, 0x0000);

        // instruction RAM register hiword
        sp8870_writereg(state, 0x8F08, ((SP8870_FIRMWARE_SIZE / 2) & 0xFFFF));

        // instruction RAM MWR
        sp8870_writereg(state, 0x8F0A, ((SP8870_FIRMWARE_SIZE / 2) >> 16));

        // do firmware upload
        fw_pos = SP8870_FIRMWARE_OFFSET;
        while (fw_pos < SP8870_FIRMWARE_SIZE + SP8870_FIRMWARE_OFFSET) {
                tx_len = (fw_pos <= SP8870_FIRMWARE_SIZE + SP8870_FIRMWARE_OFFSET - 252) ? 252 :
                         SP8870_FIRMWARE_SIZE + SP8870_FIRMWARE_OFFSET - fw_pos;
                // write register 0xCF0A
                tx_buf[0] = 0xCF;
                tx_buf[1] = 0x0A;
                memcpy(&tx_buf[2], fw_buf + fw_pos, tx_len);
                msg.addr = state->config->demod_address;
                msg.flags = 0;
                msg.buf = tx_buf;
                msg.len = tx_len + 2;
                err = i2c_transfer(state->i2c, &msg, 1);
                if (err != 1) {
                        pr_err("%s(): firmware upload failed!\n", __func__);
                        pr_err("%s(): i2c error (err == %i)\n", __func__, err);
                        return err;
                }
                fw_pos += tx_len;
        }

        dprintk("firmware upload successful!\n");
        return 0;
};

static void sp8870_microcontroller_stop(struct sp8870_state *state)
{
        sp8870_writereg(state, 0x0F08, 0x000);
        sp8870_writereg(state, 0x0F09, 0x000);

        // microcontroller STOP
        sp8870_writereg(state, 0x0F00, 0x000);
}

static void sp8870_microcontroller_start(struct sp8870_state *state)
{
        sp8870_writereg(state, 0x0F08, 0x000);
        sp8870_writereg(state, 0x0F09, 0x000);

        // microcontroller START
        sp8870_writereg(state, 0x0F00, 0x001);
        // not documented but if we don't read 0x0D01 out here
        // we don't get a correct data valid signal
        sp8870_readreg(state, 0x0D01);
}

static int sp8870_read_data_valid_signal(struct sp8870_state *state)
{
        return (sp8870_readreg(state, 0x0D02) > 0);
}

static int configure_reg0xc05(struct dtv_frontend_properties *p, u16 *reg0xc05)
{
        int known_parameters = 1;

        *reg0xc05 = 0x000;

        switch (p->modulation) {
        case QPSK:
                break;
        case QAM_16:
                *reg0xc05 |= (1 << 10);
                break;
        case QAM_64:
                *reg0xc05 |= (2 << 10);
                break;
        case QAM_AUTO:
                known_parameters = 0;
                break;
        default:
                return -EINVAL;
        }

        switch (p->hierarchy) {
        case HIERARCHY_NONE:
                break;
        case HIERARCHY_1:
                *reg0xc05 |= (1 << 7);
                break;
        case HIERARCHY_2:
                *reg0xc05 |= (2 << 7);
                break;
        case HIERARCHY_4:
                *reg0xc05 |= (3 << 7);
                break;
        case HIERARCHY_AUTO:
                known_parameters = 0;
                break;
        default:
                return -EINVAL;
        }

        switch (p->code_rate_HP) {
        case FEC_1_2:
                break;
        case FEC_2_3:
                *reg0xc05 |= (1 << 3);
                break;
        case FEC_3_4:
                *reg0xc05 |= (2 << 3);
                break;
        case FEC_5_6:
                *reg0xc05 |= (3 << 3);
                break;
        case FEC_7_8:
                *reg0xc05 |= (4 << 3);
                break;
        case FEC_AUTO:
                known_parameters = 0;
                break;
        default:
                return -EINVAL;
        }

        if (known_parameters)
                *reg0xc05 |= (2 << 1);  /* use specified parameters */
        else
                *reg0xc05 |= (1 << 1);  /* enable autoprobing */

        return 0;
}

static int sp8870_wake_up(struct sp8870_state *state)
{
        // enable TS output and interface pins
        return sp8870_writereg(state, 0xC18, 0x00D);
}

static int sp8870_set_frontend_parameters(struct dvb_frontend *fe)
{
        struct dtv_frontend_properties *p = &fe->dtv_property_cache;
        struct sp8870_state *state = fe->demodulator_priv;
        int  err;
        u16 reg0xc05;

        err = configure_reg0xc05(p, &reg0xc05);
        if (err)
                return err;

        // system controller stop
        sp8870_microcontroller_stop(state);

        // set tuner parameters
        if (fe->ops.tuner_ops.set_params) {
                fe->ops.tuner_ops.set_params(fe);
                if (fe->ops.i2c_gate_ctrl)
                        fe->ops.i2c_gate_ctrl(fe, 0);
        }

        // sample rate correction bit [23..17]
        sp8870_writereg(state, 0x0319, 0x000A);

        // sample rate correction bit [16..0]
        sp8870_writereg(state, 0x031A, 0x0AAB);

        // integer carrier offset
        sp8870_writereg(state, 0x0309, 0x0400);

        // fractional carrier offset
        sp8870_writereg(state, 0x030A, 0x0000);

        // filter for 6/7/8 Mhz channel
        if (p->bandwidth_hz == 6000000)
                sp8870_writereg(state, 0x0311, 0x0002);
        else if (p->bandwidth_hz == 7000000)
                sp8870_writereg(state, 0x0311, 0x0001);
        else
                sp8870_writereg(state, 0x0311, 0x0000);

        // scan order: 2k first = 0x0000, 8k first = 0x0001
        if (p->transmission_mode == TRANSMISSION_MODE_2K)
                sp8870_writereg(state, 0x0338, 0x0000);
        else
                sp8870_writereg(state, 0x0338, 0x0001);

        sp8870_writereg(state, 0xc05, reg0xc05);

        // read status reg in order to clear pending irqs
        err = sp8870_readreg(state, 0x200);
        if (err < 0)
                return err;

        // system controller start
        sp8870_microcontroller_start(state);

        return 0;
}

static int sp8870_init(struct dvb_frontend *fe)
{
        struct sp8870_state *state = fe->demodulator_priv;
        const struct firmware *fw = NULL;

        sp8870_wake_up(state);
        if (state->initialised)
                return 0;
        state->initialised = 1;

        dprintk("initialising frontend...\n");

        /* request the firmware, this will block until someone uploads it */
        pr_info("waiting for firmware upload (%s)...\n", SP8870_DEFAULT_FIRMWARE);
        if (state->config->request_firmware(fe, &fw, SP8870_DEFAULT_FIRMWARE)) {
                pr_err("no firmware upload (timeout or file not found?)\n");
                return -EIO;
        }

        if (sp8870_firmware_upload(state, fw)) {
                pr_err("writing firmware to device failed\n");
                release_firmware(fw);
                return -EIO;
        }
        release_firmware(fw);
        pr_info("firmware upload complete\n");

        /* enable TS output and interface pins */
        sp8870_writereg(state, 0xc18, 0x00d);

        // system controller stop
        sp8870_microcontroller_stop(state);

        // ADC mode
        sp8870_writereg(state, 0x0301, 0x0003);

        // Reed Solomon parity bytes passed to output
        sp8870_writereg(state, 0x0C13, 0x0001);

        // MPEG clock is suppressed if no valid data
        sp8870_writereg(state, 0x0C14, 0x0001);

        /* bit 0x010: enable data valid signal */
        sp8870_writereg(state, 0x0D00, 0x010);
        sp8870_writereg(state, 0x0D01, 0x000);

        return 0;
}

static int sp8870_read_status(struct dvb_frontend *fe,
                              enum fe_status *fe_status)
{
        struct sp8870_state *state = fe->demodulator_priv;
        int status;
        int signal;

        *fe_status = 0;

        status = sp8870_readreg(state, 0x0200);
        if (status < 0)
                return -EIO;

        signal = sp8870_readreg(state, 0x0303);
        if (signal < 0)
                return -EIO;

        if (signal > 0x0F)
                *fe_status |= FE_HAS_SIGNAL;
        if (status & 0x08)
                *fe_status |= FE_HAS_SYNC;
        if (status & 0x04)
                *fe_status |= FE_HAS_LOCK | FE_HAS_CARRIER | FE_HAS_VITERBI;

        return 0;
}

static int sp8870_read_ber(struct dvb_frontend *fe, u32 *ber)
{
        struct sp8870_state *state = fe->demodulator_priv;
        int ret;
        u32 tmp;

        *ber = 0;

        ret = sp8870_readreg(state, 0xC08);
        if (ret < 0)
                return -EIO;

        tmp = ret & 0x3F;

        ret = sp8870_readreg(state, 0xC07);
        if (ret < 0)
                return -EIO;

        tmp = ret << 6;
        if (tmp >= 0x3FFF0)
                tmp = ~0;

        *ber = tmp;

        return 0;
}

static int sp8870_read_signal_strength(struct dvb_frontend *fe,  u16 *signal)
{
        struct sp8870_state *state = fe->demodulator_priv;
        int ret;
        u16 tmp;

        *signal = 0;

        ret = sp8870_readreg(state, 0x306);
        if (ret < 0)
                return -EIO;

        tmp = ret << 8;

        ret = sp8870_readreg(state, 0x303);
        if (ret < 0)
                return -EIO;

        tmp |= ret;

        if (tmp)
                *signal = 0xFFFF - tmp;

        return 0;
}

static int sp8870_read_uncorrected_blocks(struct dvb_frontend *fe, u32 *ublocks)
{
        struct sp8870_state *state = fe->demodulator_priv;
        int ret;

        *ublocks = 0;

        ret = sp8870_readreg(state, 0xC0C);
        if (ret < 0)
                return -EIO;

        if (ret == 0xFFFF)
                ret = ~0;

        *ublocks = ret;

        return 0;
}

/* number of trials to recover from lockup */
#define MAXTRIALS 5
/* maximum checks for data valid signal */
#define MAXCHECKS 100

/* only for debugging: counter for detected lockups */
static int lockups;
/* only for debugging: counter for channel switches */
static int switches;

static int sp8870_set_frontend(struct dvb_frontend *fe)
{
        struct dtv_frontend_properties *p = &fe->dtv_property_cache;
        struct sp8870_state *state = fe->demodulator_priv;

        /*
         *  The firmware of the sp8870 sometimes locks up after setting frontend parameters.
         *  We try to detect this by checking the data valid signal.
         *  If it is not set after MAXCHECKS we try to recover the lockup by setting
         *  the frontend parameters again.
         */

        int err = 0;
        int valid = 0;
        int trials = 0;
        int check_count = 0;

        dprintk("frequency = %i\n", p->frequency);

        for (trials = 1; trials <= MAXTRIALS; trials++) {
                err = sp8870_set_frontend_parameters(fe);
                if (err)
                        return err;

                for (check_count = 0; check_count < MAXCHECKS; check_count++) {
//                      valid = ((sp8870_readreg(i2c, 0x0200) & 4) == 0);
                        valid = sp8870_read_data_valid_signal(state);
                        if (valid) {
                                dprintk("delay = %i usec\n", check_count * 10);
                                break;
                        }
                        usleep_range(10, 20);
                }
                if (valid)
                        break;
        }

        if (!valid) {
                pr_err("%s(): firmware crash!!!!!!\n", __func__);
                return -EIO;
        }

        if (debug) {
                if (valid) {
                        if (trials > 1) {
                                pr_info("%s(): firmware lockup!!!\n", __func__);
                                pr_info("%s(): recovered after %i trial(s))\n",  __func__, trials - 1);
                                lockups++;
                        }
                }
                switches++;
                pr_info("%s(): switches = %i lockups = %i\n", __func__, switches, lockups);
        }

        return 0;
}

static int sp8870_sleep(struct dvb_frontend *fe)
{
        struct sp8870_state *state = fe->demodulator_priv;

        // tristate TS output and disable interface pins
        return sp8870_writereg(state, 0xC18, 0x000);
}

static int sp8870_get_tune_settings(struct dvb_frontend *fe, struct dvb_frontend_tune_settings *fesettings)
{
        fesettings->min_delay_ms = 350;
        fesettings->step_size = 0;
        fesettings->max_drift = 0;
        return 0;
}

static int sp8870_i2c_gate_ctrl(struct dvb_frontend *fe, int enable)
{
        struct sp8870_state *state = fe->demodulator_priv;

        if (enable)
                return sp8870_writereg(state, 0x206, 0x001);
        else
                return sp8870_writereg(state, 0x206, 0x000);
}

static void sp8870_release(struct dvb_frontend *fe)
{
        struct sp8870_state *state = fe->demodulator_priv;

        kfree(state);
}

static const struct dvb_frontend_ops sp8870_ops;

struct dvb_frontend *sp8870_attach(const struct sp8870_config *config,
                                   struct i2c_adapter *i2c)
{
        struct sp8870_state *state = NULL;

        /* allocate memory for the internal state */
        state = kzalloc_obj(*state);
        if (!state)
                goto error;

        /* setup the state */
        state->config = config;
        state->i2c = i2c;
        state->initialised = 0;

        /* check if the demod is there */
        if (sp8870_readreg(state, 0x0200) < 0)
                goto error;

        /* create dvb_frontend */
        memcpy(&state->frontend.ops, &sp8870_ops, sizeof(sp8870_ops));
        state->frontend.demodulator_priv = state;
        return &state->frontend;

error:
        kfree(state);
        return NULL;
}
EXPORT_SYMBOL_GPL(sp8870_attach);

static const struct dvb_frontend_ops sp8870_ops = {
        .delsys = { SYS_DVBT },
        .info = {
                .name                   = "Spase SP8870 DVB-T",
                .frequency_min_hz       = 470 * MHz,
                .frequency_max_hz       = 860 * MHz,
                .frequency_stepsize_hz  = 166666,
                .caps                   = FE_CAN_FEC_1_2 | FE_CAN_FEC_2_3 |
                                          FE_CAN_FEC_3_4 | FE_CAN_FEC_5_6 |
                                          FE_CAN_FEC_7_8 | FE_CAN_FEC_AUTO |
                                          FE_CAN_QPSK | FE_CAN_QAM_16 |
                                          FE_CAN_QAM_64 | FE_CAN_QAM_AUTO |
                                          FE_CAN_HIERARCHY_AUTO |  FE_CAN_RECOVER
        },

        .release = sp8870_release,

        .init = sp8870_init,
        .sleep = sp8870_sleep,
        .i2c_gate_ctrl = sp8870_i2c_gate_ctrl,

        .set_frontend = sp8870_set_frontend,
        .get_tune_settings = sp8870_get_tune_settings,

        .read_status = sp8870_read_status,
        .read_ber = sp8870_read_ber,
        .read_signal_strength = sp8870_read_signal_strength,
        .read_ucblocks = sp8870_read_uncorrected_blocks,
};

module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "Turn on/off frontend debugging (default:off).");

MODULE_DESCRIPTION("Spase SP8870 DVB-T Demodulator driver");
MODULE_AUTHOR("Juergen Peitz");
MODULE_LICENSE("GPL");