/*
 * eSPI controller driver.
 *
 * Copyright 2010-2011 Freescale Semiconductor, Inc.
 * Author: Mingkai Hu (Mingkai.hu@freescale.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>

#include <malloc.h>
#include <spi.h>
#include <asm/immap_85xx.h>

struct fsl_spi_slave {
	struct spi_slave slave;
	unsigned int	div16;
	unsigned int	pm;
	unsigned int	mode;
	size_t		cmd_len;
	u8		cmd_buf[16];
	size_t		data_len;
	unsigned int    max_transfer_length;
};

#define to_fsl_spi_slave(s) container_of(s, struct fsl_spi_slave, slave)

#define ESPI_MAX_CS_NUM		4

#define ESPI_EV_RNE		(1 << 9)
#define ESPI_EV_TNF		(1 << 8)

#define ESPI_MODE_EN		(1 << 31)	/* Enable interface */
#define ESPI_MODE_TXTHR(x)	((x) << 8)	/* Tx FIFO threshold */
#define ESPI_MODE_RXTHR(x)	((x) << 0)	/* Rx FIFO threshold */

#define ESPI_COM_CS(x)		((x) << 30)
#define ESPI_COM_TRANLEN(x)	((x) << 0)

#define ESPI_CSMODE_CI_INACTIVEHIGH	(1 << 31)
#define ESPI_CSMODE_CP_BEGIN_EDGCLK	(1 << 30)
#define ESPI_CSMODE_REV_MSB_FIRST	(1 << 29)
#define ESPI_CSMODE_DIV16		(1 << 28)
#define ESPI_CSMODE_PM(x)		((x) << 24)
#define ESPI_CSMODE_POL_ASSERTED_LOW	(1 << 20)
#define ESPI_CSMODE_LEN(x)		((x) << 16)
#define ESPI_CSMODE_CSBEF(x)		((x) << 12)
#define ESPI_CSMODE_CSAFT(x)		((x) << 8)
#define ESPI_CSMODE_CSCG(x)		((x) << 3)

#define ESPI_CSMODE_INIT_VAL (ESPI_CSMODE_POL_ASSERTED_LOW | \
		ESPI_CSMODE_CSBEF(0) | ESPI_CSMODE_CSAFT(0) | \
		ESPI_CSMODE_CSCG(1))

#define ESPI_MAX_DATA_TRANSFER_LEN 0xFFF0

struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
		unsigned int max_hz, unsigned int mode)
{
	struct fsl_spi_slave *fsl;
	sys_info_t sysinfo;
	unsigned long spibrg = 0;
	unsigned char pm = 0;

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

	fsl = malloc(sizeof(struct fsl_spi_slave));
	if (!fsl)
		return NULL;

	fsl->slave.bus = bus;
	fsl->slave.cs = cs;
	fsl->mode = mode;
	fsl->max_transfer_length = ESPI_MAX_DATA_TRANSFER_LEN;

	/* Set eSPI BRG clock source */
	get_sys_info(&sysinfo);
	spibrg = sysinfo.freqSystemBus / 2;
	fsl->div16 = 0;
	if ((spibrg / max_hz) > 32) {
		fsl->div16 = ESPI_CSMODE_DIV16;
		pm = spibrg / (max_hz * 16 * 2);
		if (pm > 16) {
			pm = 16;
			debug("Requested speed is too low: %d Hz, %ld Hz "
				"is used.\n", max_hz, spibrg / (32 * 16));
		}
	} else
		pm = spibrg / (max_hz * 2);
	if (pm)
		pm--;
	fsl->pm = pm;

	return &fsl->slave;
}

void spi_free_slave(struct spi_slave *slave)
{
	struct fsl_spi_slave *fsl = to_fsl_spi_slave(slave);
	free(fsl);
}

void spi_init(void)
{

}

int spi_claim_bus(struct spi_slave *slave)
{
	struct fsl_spi_slave *fsl = to_fsl_spi_slave(slave);
	ccsr_espi_t *espi = (void *)(CONFIG_SYS_MPC85xx_ESPI_ADDR);
	unsigned char pm = fsl->pm;
	unsigned int cs = slave->cs;
	unsigned int mode =  fsl->mode;
	unsigned int div16 = fsl->div16;
	int i;

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

	/* Enable eSPI interface */
	out_be32(&espi->mode, ESPI_MODE_RXTHR(3)
			| ESPI_MODE_TXTHR(4) | ESPI_MODE_EN);

	out_be32(&espi->event, 0xffffffff); /* Clear all eSPI events */
	out_be32(&espi->mask, 0x00000000); /* Mask  all eSPI interrupts */

	/* Init CS mode interface */
	for (i = 0; i < ESPI_MAX_CS_NUM; i++)
		out_be32(&espi->csmode[i], ESPI_CSMODE_INIT_VAL);

	out_be32(&espi->csmode[cs], in_be32(&espi->csmode[cs]) &
		~(ESPI_CSMODE_PM(0xF) | ESPI_CSMODE_DIV16
		| ESPI_CSMODE_CI_INACTIVEHIGH | ESPI_CSMODE_CP_BEGIN_EDGCLK
		| ESPI_CSMODE_REV_MSB_FIRST | ESPI_CSMODE_LEN(0xF)));

	/* Set eSPI BRG clock source */
	out_be32(&espi->csmode[cs], in_be32(&espi->csmode[cs])
		| ESPI_CSMODE_PM(pm) | div16);

	/* Set eSPI mode */
	if (mode & SPI_CPHA)
		out_be32(&espi->csmode[cs], in_be32(&espi->csmode[cs])
			| ESPI_CSMODE_CP_BEGIN_EDGCLK);
	if (mode & SPI_CPOL)
		out_be32(&espi->csmode[cs], in_be32(&espi->csmode[cs])
			| ESPI_CSMODE_CI_INACTIVEHIGH);

	/* Character bit order: msb first */
	out_be32(&espi->csmode[cs], in_be32(&espi->csmode[cs])
		| ESPI_CSMODE_REV_MSB_FIRST);

	/* Character length in bits, between 0x3~0xf, i.e. 4bits~16bits */
	out_be32(&espi->csmode[cs], in_be32(&espi->csmode[cs])
		| ESPI_CSMODE_LEN(7));

	return 0;
}

void spi_release_bus(struct spi_slave *slave)
{

}

int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *data_out,
		void *data_in, unsigned long flags)
{
	struct fsl_spi_slave *fsl = to_fsl_spi_slave(slave);
	ccsr_espi_t *espi = (void *)(CONFIG_SYS_MPC85xx_ESPI_ADDR);
	unsigned int tmpdout, tmpdin, event;
	const void *dout = NULL;
	void *din = NULL;
	int len = 0;
	int num_blks, num_chunks, max_tran_len, tran_len;
	int num_bytes;
	unsigned char *ch;
	unsigned char *buffer = NULL;
	size_t buf_len;
	u8 *cmd_buf = fsl->cmd_buf;
	size_t cmd_len = fsl->cmd_len;
	size_t data_len = bitlen / 8;
	size_t rx_offset = 0;

	max_tran_len = fsl->max_transfer_length;
	switch (flags) {
	case SPI_XFER_BEGIN:
		cmd_len = fsl->cmd_len = data_len;
		memcpy(cmd_buf, data_out, cmd_len);
		return 0;
	case 0:
	case SPI_XFER_END:
		if (bitlen == 0) {
			spi_cs_deactivate(slave);
			return 0;
		}
		buf_len = 2 * cmd_len + min(data_len, max_tran_len);
		len = cmd_len + data_len;
		rx_offset = cmd_len;
		buffer = (unsigned char *)malloc(buf_len);
		if (!buffer) {
			debug("SF: Failed to malloc memory.\n");
			return 1;
		}
		memcpy(buffer, cmd_buf, cmd_len);
		if (data_in == NULL)
			memcpy(buffer + cmd_len, data_out, data_len);
		break;
	case SPI_XFER_BEGIN | SPI_XFER_END:
		len = data_len;
		buffer = (unsigned char *)malloc(len * 2);
		if (!buffer) {
			debug("SF: Failed to malloc memory.\n");
			return 1;
		}
		memcpy(buffer, data_out, len);
		rx_offset = len;
		cmd_len = 0;
		break;
	}

	debug("spi_xfer: slave %u:%u dout %08X(%p) din %08X(%p) len %u\n",
	      slave->bus, slave->cs, *(uint *) dout,
	      dout, *(uint *) din, din, len);

	num_chunks = data_len / max_tran_len +
		(data_len % max_tran_len ? 1 : 0);
	while (num_chunks--) {
		if (data_in)
			din = buffer + rx_offset;
		dout = buffer;
		tran_len = min(data_len , max_tran_len);
		num_blks = (tran_len + cmd_len) / 4 +
			((tran_len + cmd_len) % 4 ? 1 : 0);
		num_bytes = (tran_len + cmd_len) % 4;
		fsl->data_len = tran_len + cmd_len;
		spi_cs_activate(slave);

		/* Clear all eSPI events */
		out_be32(&espi->event , 0xffffffff);
		/* handle data in 32-bit chunks */
		while (num_blks--) {

			event = in_be32(&espi->event);
			if (event & ESPI_EV_TNF) {
				tmpdout = *(u32 *)dout;

				/* Set up the next iteration */
				if (len > 4) {
					len -= 4;
					dout += 4;
				}

				out_be32(&espi->tx, tmpdout);
				out_be32(&espi->event, ESPI_EV_TNF);
				debug("***spi_xfer:...%08x written\n", tmpdout);
			}

			/* Wait for eSPI transmit to get out */
			udelay(80);

			event = in_be32(&espi->event);
			if (event & ESPI_EV_RNE) {
				tmpdin = in_be32(&espi->rx);
				if (num_blks == 0 && num_bytes != 0) {
					ch = (unsigned char *)&tmpdin;
					while (num_bytes--)
						*(unsigned char *)din++ = *ch++;
				} else {
					*(u32 *) din = tmpdin;
					din += 4;
				}

				out_be32(&espi->event, in_be32(&espi->event)
						| ESPI_EV_RNE);
				debug("***spi_xfer:...%08x readed\n", tmpdin);
			}
		}
		if (data_in) {
			memcpy(data_in, buffer + 2 * cmd_len, tran_len);
			if (*buffer == 0x0b) {
				data_in += tran_len;
				data_len -= tran_len;
				*(int *)buffer += tran_len;
			}
		}
		spi_cs_deactivate(slave);
	}

	free(buffer);
	return 0;
}

int spi_cs_is_valid(unsigned int bus, unsigned int cs)
{
	return bus == 0 && cs < ESPI_MAX_CS_NUM;
}

void spi_cs_activate(struct spi_slave *slave)
{
	struct fsl_spi_slave *fsl = to_fsl_spi_slave(slave);
	ccsr_espi_t *espi = (void *)(CONFIG_SYS_MPC85xx_ESPI_ADDR);
	unsigned int com = 0;
	size_t data_len = fsl->data_len;

	com &= ~(ESPI_COM_CS(0x3) | ESPI_COM_TRANLEN(0xFFFF));
	com |= ESPI_COM_CS(slave->cs);
	com |= ESPI_COM_TRANLEN(data_len - 1);
	out_be32(&espi->com, com);
}

void spi_cs_deactivate(struct spi_slave *slave)
{
	ccsr_espi_t *espi = (void *)(CONFIG_SYS_MPC85xx_ESPI_ADDR);

	/* clear the RXCNT and TXCNT */
	out_be32(&espi->mode, in_be32(&espi->mode) & (~ESPI_MODE_EN));
	out_be32(&espi->mode, in_be32(&espi->mode) | ESPI_MODE_EN);
}