/*
 * Altera SPI driver
 *
 * based on bfin_spi.c
 * Copyright (c) 2005-2008 Analog Devices Inc.
 * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */
#include <common.h>
#include <asm/io.h>
#include <malloc.h>
#include <spi.h>

struct altera_spi_regs {
	u32	rxdata;
	u32	txdata;
	u32	status;
	u32	control;
	u32	_reserved;
	u32	slave_sel;
};

#define ALTERA_SPI_STATUS_ROE_MSK	(1 << 3)
#define ALTERA_SPI_STATUS_TOE_MSK	(1 << 4)
#define ALTERA_SPI_STATUS_TMT_MSK	(1 << 5)
#define ALTERA_SPI_STATUS_TRDY_MSK	(1 << 6)
#define ALTERA_SPI_STATUS_RRDY_MSK	(1 << 7)
#define ALTERA_SPI_STATUS_E_MSK		(1 << 8)

#define ALTERA_SPI_CONTROL_IROE_MSK	(1 << 3)
#define ALTERA_SPI_CONTROL_ITOE_MSK	(1 << 4)
#define ALTERA_SPI_CONTROL_ITRDY_MSK	(1 << 6)
#define ALTERA_SPI_CONTROL_IRRDY_MSK	(1 << 7)
#define ALTERA_SPI_CONTROL_IE_MSK	(1 << 8)
#define ALTERA_SPI_CONTROL_SSO_MSK	(1 << 10)

#ifndef CONFIG_SYS_ALTERA_SPI_LIST
#define CONFIG_SYS_ALTERA_SPI_LIST { CONFIG_SYS_SPI_BASE }
#endif

static ulong altera_spi_base_list[] = CONFIG_SYS_ALTERA_SPI_LIST;

struct altera_spi_slave {
	struct spi_slave	slave;
	struct altera_spi_regs	*regs;
};
#define to_altera_spi_slave(s) container_of(s, struct altera_spi_slave, slave)

__weak int spi_cs_is_valid(unsigned int bus, unsigned int cs)
{
	return bus < ARRAY_SIZE(altera_spi_base_list) && cs < 32;
}

__weak void spi_cs_activate(struct spi_slave *slave)
{
	struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
	writel(1 << slave->cs, &altspi->regs->slave_sel);
	writel(ALTERA_SPI_CONTROL_SSO_MSK, &altspi->regs->control);
}

__weak void spi_cs_deactivate(struct spi_slave *slave)
{
	struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
	writel(0, &altspi->regs->control);
	writel(0, &altspi->regs->slave_sel);
}

void spi_init(void)
{
}

void spi_set_speed(struct spi_slave *slave, uint hz)
{
	/* altera spi core does not support programmable speed */
}

struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
				  unsigned int max_hz, unsigned int mode)
{
	struct altera_spi_slave *altspi;

	if (!spi_cs_is_valid(bus, cs))
		return NULL;

	altspi = spi_alloc_slave(struct altera_spi_slave, bus, cs);
	if (!altspi)
		return NULL;

	altspi->regs = (struct altera_spi_regs *)altera_spi_base_list[bus];
	debug("%s: bus:%i cs:%i base:%p\n", __func__, bus, cs, altspi->regs);

	return &altspi->slave;
}

void spi_free_slave(struct spi_slave *slave)
{
	struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
	free(altspi);
}

int spi_claim_bus(struct spi_slave *slave)
{
	struct altera_spi_slave *altspi = to_altera_spi_slave(slave);

	debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs);
	writel(0, &altspi->regs->control);
	writel(0, &altspi->regs->slave_sel);
	return 0;
}

void spi_release_bus(struct spi_slave *slave)
{
	struct altera_spi_slave *altspi = to_altera_spi_slave(slave);

	debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs);
	writel(0, &altspi->regs->slave_sel);
}

#ifndef CONFIG_ALTERA_SPI_IDLE_VAL
# define CONFIG_ALTERA_SPI_IDLE_VAL 0xff
#endif

int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
	     void *din, unsigned long flags)
{
	struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
	/* assume spi core configured to do 8 bit transfers */
	uint bytes = bitlen / 8;
	const uchar *txp = dout;
	uchar *rxp = din;

	debug("%s: bus:%i cs:%i bitlen:%i bytes:%i flags:%lx\n", __func__,
	      slave->bus, slave->cs, bitlen, bytes, flags);

	if (bitlen == 0)
		goto done;

	if (bitlen % 8) {
		flags |= SPI_XFER_END;
		goto done;
	}

	/* empty read buffer */
	if (readl(&altspi->regs->status) & ALTERA_SPI_STATUS_RRDY_MSK)
		readl(&altspi->regs->rxdata);

	if (flags & SPI_XFER_BEGIN)
		spi_cs_activate(slave);

	while (bytes--) {
		uchar d = txp ? *txp++ : CONFIG_ALTERA_SPI_IDLE_VAL;

		debug("%s: tx:%x ", __func__, d);
		writel(d, &altspi->regs->txdata);

		while (!(readl(&altspi->regs->status) & ALTERA_SPI_STATUS_RRDY_MSK))
			;

		d = readl(&altspi->regs->rxdata);
		if (rxp)
			*rxp++ = d;

		debug("rx:%x\n", d);
	}

done:
	if (flags & SPI_XFER_END)
		spi_cs_deactivate(slave);

	return 0;
}