// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2020, The Linux Foundation. All rights reserved.
 */
#include <linux/delay.h>
#include <linux/console.h>
#include <linux/serial_core.h>
#include <linux/io.h>


#define SE_UART_TX_TRANS_CFG		(0x25C)
#define SE_UART_TX_WORD_LEN		(0x268)
#define SE_UART_TX_STOP_BIT_LEN		(0x26C)
#define SE_UART_TX_TRANS_LEN		(0x270)
#define SE_UART_TX_PARITY_CFG		(0x2A4)
/* SE_UART_TRANS_CFG */
#define UART_CTS_MASK		(BIT(1))
/* UART M_CMD OP codes */
#define UART_START_TX		(0x1)

#define UART_OVERSAMPLING	(32)
#define DEF_FIFO_DEPTH_WORDS	(16)
#define DEF_TX_WM		(2)
#define DEF_FIFO_WIDTH_BITS	(32)

#define GENI_INIT_CFG_REVISION		(0x0)
#define GENI_S_INIT_CFG_REVISION	(0x4)
#define GENI_FORCE_DEFAULT_REG		(0x20)
#define GENI_OUTPUT_CTRL		(0x24)
#define GENI_CGC_CTRL			(0x28)
#define SE_GENI_STATUS			(0x40)
#define GENI_SER_M_CLK_CFG		(0x48)
#define GENI_CLK_CTRL_RO		(0x60)
#define GENI_IF_FIFO_DISABLE_RO		(0x64)
#define GENI_FW_REVISION_RO		(0x68)
#define SE_GENI_CLK_SEL			(0x7C)
#define SE_GENI_BYTE_GRAN		(0x254)
#define SE_GENI_TX_PACKING_CFG0		(0x260)
#define SE_GENI_TX_PACKING_CFG1		(0x264)
#define SE_GENI_M_CMD0			(0x600)
#define SE_GENI_M_CMD_CTRL_REG		(0x604)
#define SE_GENI_M_IRQ_STATUS		(0x610)
#define SE_GENI_M_IRQ_EN		(0x614)
#define SE_GENI_M_IRQ_CLEAR		(0x618)
#define SE_GENI_TX_FIFOn		(0x700)
#define SE_GENI_TX_FIFO_STATUS		(0x800)
#define SE_GENI_TX_WATERMARK_REG	(0x80C)
#define SE_GENI_IOS			(0x908)
#define SE_GENI_M_GP_LENGTH		(0x910)
#define SE_IRQ_EN			(0xE1C)
#define SE_HW_PARAM_0			(0xE24)
#define SE_HW_PARAM_1			(0xE28)

/* GENI_OUTPUT_CTRL fields */
#define DEFAULT_IO_OUTPUT_CTRL_MSK	(GENMASK(6, 0))

/* GENI_FORCE_DEFAULT_REG fields */
#define FORCE_DEFAULT	(BIT(0))

/* GENI_CGC_CTRL fields */
#define CFG_AHB_CLK_CGC_ON		(BIT(0))
#define CFG_AHB_WR_ACLK_CGC_ON		(BIT(1))
#define DATA_AHB_CLK_CGC_ON		(BIT(2))
#define SCLK_CGC_ON			(BIT(3))
#define TX_CLK_CGC_ON			(BIT(4))
#define RX_CLK_CGC_ON			(BIT(5))
#define EXT_CLK_CGC_ON			(BIT(6))
#define PROG_RAM_HCLK_OFF		(BIT(8))
#define PROG_RAM_SCLK_OFF		(BIT(9))
#define DEFAULT_CGC_EN			(GENMASK(6, 0))

/* GENI_STATUS fields */
#define M_GENI_CMD_ACTIVE		(BIT(0))

/* GENI_SER_M_CLK_CFG/GENI_SER_S_CLK_CFG */
#define SER_CLK_EN			(BIT(0))
#define CLK_DIV_MSK			(GENMASK(15, 4))
#define CLK_DIV_SHFT			(4)

/* CLK_CTRL_RO fields */

/* FIFO_IF_DISABLE_RO fields */
#define FIFO_IF_DISABLE			(BIT(0))

/* FW_REVISION_RO fields */
#define FW_REV_PROTOCOL_MSK	(GENMASK(15, 8))
#define FW_REV_PROTOCOL_SHFT	(8)
#define FW_REV_VERSION_MSK	(GENMASK(7, 0))

/* GENI_CLK_SEL fields */
#define CLK_SEL_MSK		(GENMASK(2, 0))

/* SE_GENI_DMA_MODE_EN */
#define GENI_DMA_MODE_EN	(BIT(0))

/* GENI_M_CMD0 fields */
#define M_OPCODE_MSK		(GENMASK(31, 27))
#define M_OPCODE_SHFT		(27)
#define M_PARAMS_MSK		(GENMASK(26, 0))

/* GENI_M_CMD_CTRL_REG */
#define M_GENI_CMD_CANCEL	BIT(2)
#define M_GENI_CMD_ABORT	BIT(1)
#define M_GENI_DISABLE		BIT(0)

/* GENI_M_IRQ_EN fields */
#define M_CMD_DONE_EN		(BIT(0))
#define M_CMD_OVERRUN_EN	(BIT(1))
#define M_ILLEGAL_CMD_EN	(BIT(2))
#define M_CMD_FAILURE_EN	(BIT(3))
#define M_CMD_CANCEL_EN		(BIT(4))
#define M_CMD_ABORT_EN		(BIT(5))
#define M_TIMESTAMP_EN		(BIT(6))
#define M_GP_SYNC_IRQ_0_EN	(BIT(8))
#define M_IO_DATA_DEASSERT_EN	(BIT(22))
#define M_IO_DATA_ASSERT_EN	(BIT(23))
#define M_TX_FIFO_RD_ERR_EN	(BIT(28))
#define M_TX_FIFO_WR_ERR_EN	(BIT(29))
#define M_TX_FIFO_WATERMARK_EN	(BIT(30))
#define M_SEC_IRQ_EN		(BIT(31))
#define M_COMMON_GENI_M_IRQ_EN	(GENMASK(6, 1) | \
				M_IO_DATA_DEASSERT_EN | \
				M_IO_DATA_ASSERT_EN | M_TX_FIFO_RD_ERR_EN | \
				M_TX_FIFO_WR_ERR_EN)


/* GENI_TX_FIFO_STATUS fields */
#define TX_FIFO_WC		(GENMASK(27, 0))

/* SE_IRQ_EN fields */
#define GENI_M_IRQ_EN		(BIT(2))

/* SE_HW_PARAM_0 fields */
#define TX_FIFO_WIDTH_MSK	(GENMASK(29, 24))
#define TX_FIFO_WIDTH_SHFT	(24)
#define TX_FIFO_DEPTH_MSK	(GENMASK(21, 16))
#define TX_FIFO_DEPTH_SHFT	(16)

enum se_protocol_types {
	NONE,
	SPI,
	UART,
	I2C,
	I3C,
};

static void geni_write_reg_earlycon(unsigned int value,
						void __iomem *base, int offset)
{
	writel_relaxed(value, (base + offset));
}

static unsigned int geni_read_reg_earlycon(void __iomem *base, int offset)
{
	return readl_relaxed(base + offset);
}

static int get_se_proto_earlycon(void __iomem *base)
{
	int proto;

	proto = ((geni_read_reg_earlycon(base, GENI_FW_REVISION_RO)
			& FW_REV_PROTOCOL_MSK) >> FW_REV_PROTOCOL_SHFT);
	return proto;
}

static void se_get_packing_config_earlycon(int bpw, int pack_words,
	bool msb_to_lsb, unsigned long *cfg0, unsigned long *cfg1)
{
	u32 cfg[4] = {0};
	int len;
	int temp_bpw = bpw;
	int idx_start = (msb_to_lsb ? (bpw - 1) : 0);
	int idx = idx_start;
	int idx_delta = (msb_to_lsb ? -BITS_PER_BYTE : BITS_PER_BYTE);
	int ceil_bpw = ((bpw & (BITS_PER_BYTE - 1)) ?
			((bpw & ~(BITS_PER_BYTE - 1)) + BITS_PER_BYTE) : bpw);
	int iter = (ceil_bpw * pack_words) >> 3;
	int i;

	if (unlikely(iter <= 0 || iter > 4)) {
		*cfg0 = 0;
		*cfg1 = 0;
		return;
	}

	for (i = 0; i < iter; i++) {
		len = (temp_bpw < BITS_PER_BYTE) ?
				(temp_bpw - 1) : BITS_PER_BYTE - 1;
		cfg[i] = ((idx << 5) | (msb_to_lsb << 4) | (len << 1));
		idx = ((temp_bpw - BITS_PER_BYTE) <= 0) ?
				((i + 1) * BITS_PER_BYTE) + idx_start :
				idx + idx_delta;
		temp_bpw = ((temp_bpw - BITS_PER_BYTE) <= 0) ?
				bpw : (temp_bpw - BITS_PER_BYTE);
	}
	cfg[iter - 1] |= 1;
	*cfg0 = cfg[0] | (cfg[1] << 10);
	*cfg1 = cfg[2] | (cfg[3] << 10);
}

static int se_geni_irq_en_earlycon(void __iomem *base)
{
	unsigned int common_geni_m_irq_en;

	common_geni_m_irq_en = geni_read_reg_earlycon(base,
							SE_GENI_M_IRQ_EN);
	common_geni_m_irq_en |= M_COMMON_GENI_M_IRQ_EN;
	geni_write_reg_earlycon(common_geni_m_irq_en, base,
							SE_GENI_M_IRQ_EN);
	return 0;
}

static int se_io_set_mode_earlycon(void __iomem *base)
{
	unsigned int io_mode;

	io_mode = geni_read_reg_earlycon(base, SE_IRQ_EN);

	io_mode |= (GENI_M_IRQ_EN);

	geni_write_reg_earlycon(io_mode, base, SE_IRQ_EN);
	return 0;
}

static void se_io_init_earlycon(void __iomem *base)
{
	unsigned int io_op_ctrl;
	unsigned int geni_cgc_ctrl;

	geni_cgc_ctrl = geni_read_reg_earlycon(base, GENI_CGC_CTRL);
	geni_cgc_ctrl |= DEFAULT_CGC_EN;
	io_op_ctrl = DEFAULT_IO_OUTPUT_CTRL_MSK;
	geni_write_reg_earlycon(geni_cgc_ctrl, base, GENI_CGC_CTRL);

	geni_write_reg_earlycon(io_op_ctrl, base, GENI_OUTPUT_CTRL);
	geni_write_reg_earlycon(FORCE_DEFAULT, base,
							GENI_FORCE_DEFAULT_REG);
}

static int geni_se_init_earlycon(void __iomem *base, unsigned int rx_wm,
	unsigned int rx_rfr)
{
	int ret;

	se_io_init_earlycon(base);
	ret = se_io_set_mode_earlycon(base);
	if (ret)
		return ret;

	ret = se_geni_irq_en_earlycon(base);
	return ret;
}

static int geni_se_select_fifo_mode_earlycon(void __iomem *base)
{
	unsigned int common_geni_m_irq_en;

	geni_write_reg_earlycon(0xFFFFFFFF, base, SE_GENI_M_IRQ_CLEAR);
	geni_write_reg_earlycon(0xFFFFFFFF, base, SE_IRQ_EN);

	common_geni_m_irq_en = geni_read_reg_earlycon(base,
							SE_GENI_M_IRQ_EN);
	geni_write_reg_earlycon(common_geni_m_irq_en, base,
							SE_GENI_M_IRQ_EN);
	return 0;
}

struct msm_geni_serial_earlycon_port {
	struct uart_port uport;
	char name[20];
	unsigned int tx_fifo_depth;
	unsigned int tx_fifo_width;
	unsigned int tx_wm;
	unsigned int xmit_size;
	void *console_log;
	unsigned int cur_baud;
};

#define GET_DEV_PORT(uport) \
	container_of(uport, struct msm_geni_serial_earlycon_port, uport)

static int get_clk_cfg(unsigned long clk_freq, unsigned long *ser_clk)
{
	unsigned long root_freq[] = {7372800, 14745600, 19200000, 29491200,
		32000000, 48000000, 64000000, 80000000, 96000000, 100000000,
		102400000, 112000000, 120000000, 128000000};
	int i;
	int match = -1;

	for (i = 0; i < ARRAY_SIZE(root_freq); i++) {
		if (clk_freq > root_freq[i])
			continue;

		if (!(root_freq[i] % clk_freq)) {
			match = i;
			break;
		}
	}
	if (match != -1)
		*ser_clk = root_freq[match];

	return match;
}


static int get_clk_div_rate(unsigned int baud, unsigned long *desired_clk_rate)
{
	unsigned long ser_clk;
	int dfs_index;
	int clk_div = 0;

	*desired_clk_rate = baud * UART_OVERSAMPLING;
	dfs_index = get_clk_cfg(*desired_clk_rate, &ser_clk);
	if (dfs_index < 0) {
		clk_div = -EINVAL;
		goto exit_get_clk_div_rate;
	}

	clk_div = ser_clk / *desired_clk_rate;
	*desired_clk_rate = ser_clk;
exit_get_clk_div_rate:
	return clk_div;
}


static void msm_geni_serial_wr_char(struct uart_port *uport, int ch)
{
	geni_write_reg_earlycon(ch, uport->membase, SE_GENI_TX_FIFOn);
	/*
	 * Ensure FIFO write clear goes through before
	 * next iteration.
	 */
	mb();

}

static int msm_geni_serial_poll_bit(struct uart_port *uport,
				int offset, int bit_field, bool set)
{
	int iter = 0;
	unsigned int reg;
	bool met = false;
	struct msm_geni_serial_earlycon_port *port = NULL;
	bool cond = false;
	unsigned int baud = 115200;
	unsigned int fifo_bits = DEF_FIFO_DEPTH_WORDS * DEF_FIFO_WIDTH_BITS;
	unsigned long total_iter = 1000;


	if (uport->private_data && !uart_console(uport)) {
		port = GET_DEV_PORT(uport);
		baud = (port->cur_baud ? port->cur_baud : 115200);
		fifo_bits = port->tx_fifo_depth * port->tx_fifo_width;
		/*
		 * Total polling iterations based on FIFO worth of bytes to be
		 * sent at current baud .Add a little fluff to the wait.
		 */
		total_iter = ((fifo_bits * USEC_PER_SEC) / baud) / 10;
		total_iter += 50;
	}

	while (iter < total_iter) {
		reg = geni_read_reg_earlycon(uport->membase, offset);
		cond = reg & bit_field;
		if (cond == set) {
			met = true;
			break;
		}
		udelay(10);
		iter++;
	}
	return met;
}

static void msm_geni_serial_poll_cancel_tx(struct uart_port *uport)
{
	int done = 0;
	unsigned int irq_clear = M_CMD_DONE_EN;

	done = msm_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS,
						M_CMD_DONE_EN, true);
	if (!done) {
		geni_write_reg_earlycon(M_GENI_CMD_ABORT, uport->membase,
					SE_GENI_M_CMD_CTRL_REG);
		irq_clear |= M_CMD_ABORT_EN;
		msm_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS,
							M_CMD_ABORT_EN, true);
	}
	geni_write_reg_earlycon(irq_clear, uport->membase,
				SE_GENI_M_IRQ_CLEAR);
}

static void msm_geni_serial_setup_tx(struct uart_port *uport,
				unsigned int xmit_size)
{
	u32 m_cmd = 0;

	geni_write_reg_earlycon(xmit_size, uport->membase,
				SE_UART_TX_TRANS_LEN);
	m_cmd |= (UART_START_TX << M_OPCODE_SHFT);
	geni_write_reg_earlycon(m_cmd, uport->membase, SE_GENI_M_CMD0);
	/*
	 * Writes to enable the primary sequencer should go through before
	 * exiting this function.
	 */
	mb();
}


static void
__msm_geni_serial_console_write(struct uart_port *uport, const char *s,
				unsigned int count)
{
	int new_line = 0;
	int i;
	int bytes_to_send = count;
	int fifo_depth = DEF_FIFO_DEPTH_WORDS;
	int tx_wm = DEF_TX_WM;

	for (i = 0; i < count; i++) {
		if (s[i] == '\n')
			new_line++;
	}

	bytes_to_send += new_line;
	geni_write_reg_earlycon(tx_wm, uport->membase,
					SE_GENI_TX_WATERMARK_REG);
	msm_geni_serial_setup_tx(uport, bytes_to_send);
	i = 0;
	while (i < count) {
		u32 chars_to_write = 0;
		u32 avail_fifo_bytes = (fifo_depth - tx_wm);
		/*
		 * If the WM bit never set, then the Tx state machine is not
		 * in a valid state, so break, cancel/abort any existing
		 * command. Unfortunately the current data being written is
		 * lost.
		 */
		while (!msm_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS,
						M_TX_FIFO_WATERMARK_EN, true))
			break;
		chars_to_write = min((unsigned int)(count - i),
							avail_fifo_bytes);
		if ((chars_to_write << 1) > avail_fifo_bytes)
			chars_to_write = (avail_fifo_bytes >> 1);
		uart_console_write(uport, (s + i), chars_to_write,
					msm_geni_serial_wr_char);
		geni_write_reg_earlycon(M_TX_FIFO_WATERMARK_EN,
			uport->membase, SE_GENI_M_IRQ_CLEAR);
		/* Ensure this goes through before polling for WM IRQ again.*/
		mb();
		i += chars_to_write;
	}
	msm_geni_serial_poll_cancel_tx(uport);
}


static void
msm_geni_serial_early_console_write(struct console *con, const char *s,
			unsigned int n)
{
	struct earlycon_device *dev = con->data;

	__msm_geni_serial_console_write(&dev->port, s, n);
}

static int __init
msm_geni_serial_earlycon_setup(struct earlycon_device *dev,
		const char *opt)
{
	struct uart_port *uport = &dev->port;
	int ret = 0;
	u32 tx_trans_cfg = 0;
	u32 tx_parity_cfg = 0;
	u32 rx_trans_cfg = 0;
	u32 rx_parity_cfg = 0;
	u32 stop_bit = 0;
	u32 rx_stale = 0;
	u32 bits_per_char = 0;
	u32 s_clk_cfg = 0;
	u32 baud = 115200;
	int clk_div;
	unsigned long clk_rate;
	unsigned long cfg0, cfg1;

	if (!uport->membase) {
		ret = -ENOMEM;
		goto exit_geni_serial_earlyconsetup;
	}

	if (get_se_proto_earlycon(uport->membase) != UART) {
		ret = -ENXIO;
		goto exit_geni_serial_earlyconsetup;
	}

	/*
	 * Ignore Flow control.
	 * Disable Tx Parity.
	 * Don't check Parity during Rx.
	 * Disable Rx Parity.
	 * n = 8.
	 * Stop bit = 0.
	 * Stale timeout in bit-time (3 chars worth).
	 */
	tx_trans_cfg |= UART_CTS_MASK;
	tx_parity_cfg = 0;
	rx_trans_cfg = 0;
	rx_parity_cfg = 0;
	bits_per_char = 0x8;
	stop_bit = 0;
	rx_stale = 0x18;
	clk_div = get_clk_div_rate(baud, &clk_rate);
	if (clk_div <= 0) {
		ret = -EINVAL;
		goto exit_geni_serial_earlyconsetup;
	}

	if (IS_ENABLED(CONFIG_SERIAL_MSM_GENI_HALF_SAMPLING))
		clk_div *= 2;

	s_clk_cfg |= SER_CLK_EN;
	s_clk_cfg |= (clk_div << CLK_DIV_SHFT);

	/*
	 * Make an unconditional cancel on the main sequencer to reset
	 * it else we could end up in data loss scenarios.
	 */
	geni_write_reg_earlycon(0x21, uport->membase, GENI_SER_M_CLK_CFG);
	geni_read_reg_earlycon(uport->membase, GENI_SER_M_CLK_CFG);

	msm_geni_serial_poll_cancel_tx(uport);

	se_get_packing_config_earlycon(8, 1, false, &cfg0, &cfg1);
	geni_se_init_earlycon(uport->membase, (DEF_FIFO_DEPTH_WORDS >> 1),
					(DEF_FIFO_DEPTH_WORDS - 2));
	geni_se_select_fifo_mode_earlycon(uport->membase);
	geni_write_reg_earlycon(cfg0, uport->membase,
				SE_GENI_TX_PACKING_CFG0);
	geni_write_reg_earlycon(cfg1, uport->membase,
				SE_GENI_TX_PACKING_CFG1);
	geni_write_reg_earlycon(tx_trans_cfg, uport->membase,
				SE_UART_TX_TRANS_CFG);
	geni_write_reg_earlycon(tx_parity_cfg, uport->membase,
				SE_UART_TX_PARITY_CFG);
	geni_write_reg_earlycon(bits_per_char, uport->membase,
				SE_UART_TX_WORD_LEN);
	geni_write_reg_earlycon(stop_bit, uport->membase,
				SE_UART_TX_STOP_BIT_LEN);
	geni_write_reg_earlycon(s_clk_cfg, uport->membase,
				GENI_SER_M_CLK_CFG);
	geni_read_reg_earlycon(uport->membase,
				GENI_SER_M_CLK_CFG);

	dev->con->write = msm_geni_serial_early_console_write;
	dev->con->setup = NULL;
	/*
	 * Ensure that the early console setup completes before
	 * returning.
	 */
	mb();
exit_geni_serial_earlyconsetup:
	return ret;
}
OF_EARLYCON_DECLARE(msm_geni_serial, "qcom,msm-geni-console",
		msm_geni_serial_earlycon_setup);