// 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;
			}
			udelay(10);
		}
		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(sizeof(*state), GFP_KERNEL);
	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");