/*
 * arch/ppc/boot/simple/mv64x60_tty.c
 * 
 * Bootloader version of the embedded MPSC/UART driver for the Marvell 64x60.
 * Note: Due to a GT64260A erratum, DMA will be used for UART input (via SDMA).
 *
 * Author: Mark A. Greer <mgreer@mvista.com>
 *
 * Copyright 2001 MontaVista Software Inc.
 *
 * 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 code assumes that the data cache has been disabled (L1, L2, L3). */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/serial_reg.h>
#include <asm/serial.h>
#include <asm/mv64x60_defs.h>
#include "../../../../drivers/serial/mpsc/mpsc_defs.h"

extern void udelay(long);
static void stop_dma(int chan);

static u32	mv64x60_base = CONFIG_MV64X60_NEW_BASE;

inline unsigned
mv64x60_in_le32(volatile unsigned *addr)
{
	unsigned ret;

	__asm__ __volatile__("lwbrx %0,0,%1; eieio" : "=r" (ret) :
				     "r" (addr), "m" (*addr));
	return ret;
}

inline void
mv64x60_out_le32(volatile unsigned *addr, int val)
{
	__asm__ __volatile__("stwbrx %1,0,%2; eieio" : "=m" (*addr) :
				     "r" (val), "r" (addr));
}

#define MV64x60_REG_READ(offs)						\
	(mv64x60_in_le32((volatile uint *)(mv64x60_base + (offs))))
#define MV64x60_REG_WRITE(offs, d)					\
        (mv64x60_out_le32((volatile uint *)(mv64x60_base + (offs)), (int)(d)))


typedef struct {
	u32	sdc;
	u32	sdcm;
	u32	rx_desc;
	u32	rx_buf_ptr;
	u32	scrdp;
	u32	tx_desc;
	u32	sctdp;
	u32	sftdp;
} sdma_regs_t;

static sdma_regs_t  sdma_regs[2];

#define	SDMA_REGS_INIT(s, reg_base) {			\
	(s)->sdc        = (reg_base) + SDMA_SDC;	\
	(s)->sdcm       = (reg_base) + SDMA_SDCM;	\
	(s)->rx_desc    = (reg_base) + SDMA_RX_DESC;	\
	(s)->rx_buf_ptr = (reg_base) + SDMA_RX_BUF_PTR;	\
	(s)->scrdp      = (reg_base) + SDMA_SCRDP;	\
	(s)->tx_desc    = (reg_base) + SDMA_TX_DESC;	\
	(s)->sctdp      = (reg_base) + SDMA_SCTDP;	\
	(s)->sftdp      = (reg_base) + SDMA_SFTDP;	\
}

typedef struct {
	volatile u16 bufsize;
	volatile u16 bytecnt;
	volatile u32 cmd_stat;
	volatile u32 next_desc_ptr;
	volatile u32 buffer;
} mv64x60_rx_desc_t;

typedef struct {
	volatile u16 bytecnt;
	volatile u16 shadow;
	volatile u32 cmd_stat;
	volatile u32 next_desc_ptr;
	volatile u32 buffer;
} mv64x60_tx_desc_t;

#define	MAX_RESET_WAIT	10000
#define	MAX_TX_WAIT	10000

#define	RX_NUM_DESC	2
#define	TX_NUM_DESC	2

#define	RX_BUF_SIZE	16
#define	TX_BUF_SIZE	16

static mv64x60_rx_desc_t rd[2][RX_NUM_DESC] __attribute__ ((aligned(32)));
static mv64x60_tx_desc_t td[2][TX_NUM_DESC] __attribute__ ((aligned(32)));

static char rx_buf[2][RX_NUM_DESC * RX_BUF_SIZE] __attribute__ ((aligned(32)));
static char tx_buf[2][TX_NUM_DESC * TX_BUF_SIZE] __attribute__ ((aligned(32)));

static int cur_rd[2] = { 0, 0 };
static int cur_td[2] = { 0, 0 };

static char chan_initialized[2] = { 0, 0 };


#define	RX_INIT_RDP(rdp) {			\
	(rdp)->bufsize = 2;			\
	(rdp)->bytecnt = 0;			\
	(rdp)->cmd_stat = SDMA_DESC_CMDSTAT_L |	\
			  SDMA_DESC_CMDSTAT_F |	\
			  SDMA_DESC_CMDSTAT_O;	\
}

unsigned long
serial_init(int chan, void *ignored)
{
	u32		mpsc_base, mpsc_routing_base, sdma_base, brg_bcr, cdv;
	int		i;
	extern long	mv64x60_console_baud;
	extern long	mv64x60_mpsc_clk_src;
	extern long	mv64x60_mpsc_clk_freq;

	chan = (chan == 1);  /* default to chan 0 if anything but 1 */

	if (chan_initialized[chan]) return chan;

	chan_initialized[chan] = 1;

	if (chan == 0) {
		mpsc_base = MV64x60_MPSC_0_OFFSET;
		sdma_base = MV64x60_SDMA_0_OFFSET;
		brg_bcr = MV64x60_BRG_0_OFFSET + BRG_BCR;
		SDMA_REGS_INIT(&sdma_regs[0], MV64x60_SDMA_0_OFFSET);
	}
	else {
		mpsc_base = MV64x60_MPSC_1_OFFSET;
		sdma_base = MV64x60_SDMA_1_OFFSET;
		brg_bcr = MV64x60_BRG_1_OFFSET + BRG_BCR;
		SDMA_REGS_INIT(&sdma_regs[0], MV64x60_SDMA_1_OFFSET);
	}

	mpsc_routing_base = MV64x60_MPSC_ROUTING_OFFSET;

	stop_dma(chan);

	/* Set up ring buffers */
	for (i=0; i<RX_NUM_DESC; i++) {
		RX_INIT_RDP(&rd[chan][i]);
		rd[chan][i].buffer = (u32)&rx_buf[chan][i * RX_BUF_SIZE];
		rd[chan][i].next_desc_ptr = (u32)&rd[chan][i+1];
	}
	rd[chan][RX_NUM_DESC - 1].next_desc_ptr = (u32)&rd[chan][0];

	for (i=0; i<TX_NUM_DESC; i++) {
		td[chan][i].bytecnt = 0;
		td[chan][i].shadow = 0;
		td[chan][i].buffer = (u32)&tx_buf[chan][i * TX_BUF_SIZE];
		td[chan][i].cmd_stat = SDMA_DESC_CMDSTAT_F|SDMA_DESC_CMDSTAT_L;
		td[chan][i].next_desc_ptr = (u32)&td[chan][i+1];
	}
	td[chan][TX_NUM_DESC - 1].next_desc_ptr = (u32)&td[chan][0];

	/* Set MPSC Routing */
        MV64x60_REG_WRITE(mpsc_routing_base + MPSC_MRR, 0x3ffffe38);

/* XXXX Not for 64360 XXXX*/
        MV64x60_REG_WRITE(GT64260_MPP_SERIAL_PORTS_MULTIPLEX, 0x00001102);

	/* MPSC 0/1 Rx & Tx get clocks BRG0/1 */
        MV64x60_REG_WRITE(mpsc_routing_base + MPSC_RCRR, 0x00000100);
        MV64x60_REG_WRITE(mpsc_routing_base + MPSC_TCRR, 0x00000100);

	/* clear pending interrupts */
        MV64x60_REG_WRITE(MV64x60_SDMA_INTR_OFFSET + SDMA_INTR_MASK, 0);

	MV64x60_REG_WRITE(SDMA_SCRDP + sdma_base, &rd[chan][0]);
	MV64x60_REG_WRITE(SDMA_SCTDP + sdma_base, &td[chan][TX_NUM_DESC - 1]);
	MV64x60_REG_WRITE(SDMA_SFTDP + sdma_base, &td[chan][TX_NUM_DESC - 1]);

	MV64x60_REG_WRITE(SDMA_SDC + sdma_base,
		  SDMA_SDC_RFT | SDMA_SDC_SFM | SDMA_SDC_BLMR | SDMA_SDC_BLMT |
		  (3 << 12));

	cdv = ((mv64x60_mpsc_clk_freq/(32*mv64x60_console_baud))-1);
	MV64x60_REG_WRITE(brg_bcr,
		((mv64x60_mpsc_clk_src << 18) | (1 << 16) | cdv));

	/* Put MPSC into UART mode, no null modem, 16x clock mode */
	MV64x60_REG_WRITE(MPSC_MMCRL + mpsc_base, 0x000004c4);
	MV64x60_REG_WRITE(MPSC_MMCRH + mpsc_base, 0x04400400);

        MV64x60_REG_WRITE(MPSC_CHR_1 + mpsc_base, 0);
        MV64x60_REG_WRITE(MPSC_CHR_9 + mpsc_base, 0);
        MV64x60_REG_WRITE(MPSC_CHR_10 + mpsc_base, 0);
        MV64x60_REG_WRITE(MPSC_CHR_3 + mpsc_base, 4);
        MV64x60_REG_WRITE(MPSC_CHR_4 + mpsc_base, 0);
        MV64x60_REG_WRITE(MPSC_CHR_5 + mpsc_base, 0);
        MV64x60_REG_WRITE(MPSC_CHR_6 + mpsc_base, 0);
        MV64x60_REG_WRITE(MPSC_CHR_7 + mpsc_base, 0);
        MV64x60_REG_WRITE(MPSC_CHR_8 + mpsc_base, 0);

	/* 8 data bits, 1 stop bit */
	MV64x60_REG_WRITE(MPSC_MPCR + mpsc_base, (3 << 12));
	MV64x60_REG_WRITE(SDMA_SDCM + sdma_base, SDMA_SDCM_ERD);
	MV64x60_REG_WRITE(MPSC_CHR_2 + mpsc_base, MPSC_CHR_2_EH);

	udelay(100);

	return chan;
}

static void
stop_dma(int chan)
{
	int	i;

	/* Abort SDMA Rx, Tx */
	MV64x60_REG_WRITE(sdma_regs[chan].sdcm, SDMA_SDCM_AR | SDMA_SDCM_STD);

	for (i=0; i<MAX_RESET_WAIT; i++) {
		if ((MV64x60_REG_READ(sdma_regs[chan].sdcm) &
			(SDMA_SDCM_AR | SDMA_SDCM_AT)) == 0) {
			break;
		}
		udelay(100);
	}

	return;
}

static int
wait_for_ownership(int chan)
{
	int	i;

	for (i=0; i<MAX_TX_WAIT; i++) {
		if ((MV64x60_REG_READ(sdma_regs[chan].sdcm) &
					SDMA_SDCM_TXD) == 0)
			break;
		udelay(1000);
	}

	return (i < MAX_TX_WAIT);
}

void
serial_putc(unsigned long com_port, unsigned char c)
{
	mv64x60_tx_desc_t	*tdp;

	if (wait_for_ownership(com_port) == 0) return;

	tdp = &td[com_port][cur_td[com_port]];
	if (++cur_td[com_port] >= TX_NUM_DESC) cur_td[com_port] = 0;

	*(unchar *)(tdp->buffer ^ 7) = c;
	tdp->bytecnt = 1;
	tdp->shadow = 1;
	tdp->cmd_stat = SDMA_DESC_CMDSTAT_L | SDMA_DESC_CMDSTAT_F |
		SDMA_DESC_CMDSTAT_O;

	MV64x60_REG_WRITE(sdma_regs[com_port].sctdp, tdp);
	MV64x60_REG_WRITE(sdma_regs[com_port].sftdp, tdp);
	MV64x60_REG_WRITE(sdma_regs[com_port].sdcm,
		MV64x60_REG_READ(sdma_regs[com_port].sdcm) | SDMA_SDCM_TXD);

	return;
}

unsigned char
serial_getc(unsigned long com_port)
{
	mv64x60_rx_desc_t	*rdp;
	unchar			c = '\0';

	rdp = &rd[com_port][cur_rd[com_port]];

	if ((rdp->cmd_stat & (SDMA_DESC_CMDSTAT_O|SDMA_DESC_CMDSTAT_ES)) == 0) {
		c = *(unchar *)(rdp->buffer ^ 7);
		RX_INIT_RDP(rdp);
		if (++cur_rd[com_port] >= RX_NUM_DESC) cur_rd[com_port] = 0;
	}

	return c;
}

int
serial_tstc(unsigned long com_port)
{
	mv64x60_rx_desc_t	*rdp;
	int			loop_count = 0;
	int			rc = 0;

	rdp = &rd[com_port][cur_rd[com_port]];

	/* Go thru rcv desc's until empty looking for one with data (no error)*/
	while (((rdp->cmd_stat & SDMA_DESC_CMDSTAT_O) == 0) &&
	       (loop_count++ < RX_NUM_DESC)) {

		/* If there was an error, reinit the desc & continue */
		if ((rdp->cmd_stat & SDMA_DESC_CMDSTAT_ES) != 0) {
			RX_INIT_RDP(rdp);
			if (++cur_rd[com_port] >= RX_NUM_DESC) {
				cur_rd[com_port] = 0;
			}
			rdp = (mv64x60_rx_desc_t *)rdp->next_desc_ptr;
		}
		else {
			rc = 1;
			break;
		}
	}

	return rc;
}

void
serial_close(unsigned long com_port)
{
	stop_dma(com_port);
	return;
}