/*
 * PicoDrive
 * (C) notaz, 2009,2010
 *
 * This work is licensed under the terms of MAME license.
 * See COPYING file in the top-level directory.
 */
/*
 * <random_info=mem_map>
 * 00000000-029fffff linux (42MB)
 * 02a00000-02dfffff fb (4MB, 153600B really used)
 * 02e00000-02ffffff sound dma (2MB)
 * 03000000-03ffffff MPEGDEC (?, 16MB)
 * </random_info>
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/fb.h>

#include "soc.h"
#include "plat_gp2x.h"
#include "../common/emu.h"
#include "../common/plat.h"
#include "../common/arm_utils.h"
#include "pollux_set.h"

static volatile unsigned short *memregs;
static volatile unsigned int   *memregl;
static int memdev = -1;
static int battdev = -1;

extern void *gp2x_screens[4];

#define fb_buf_count 4
static unsigned int fb_paddr[fb_buf_count];
static int fb_work_buf;
static int fbdev = -1;

static char cpuclk_was_changed = 0;
static unsigned short memtimex_old[2];
static unsigned int pllsetreg0_old;
static unsigned int timer_drift; // count per real second
static int last_pal_setting = 0;


/* misc */
static void pollux_set_fromenv(const char *env_var)
{
	const char *set_string;
	set_string = getenv(env_var);
	if (set_string)
		pollux_set(memregs, set_string);
	else
		printf("env var %s not defined.\n", env_var);
}

/* video stuff */
static void pollux_video_flip(int buf_count)
{
	memregl[0x406C>>2] = fb_paddr[fb_work_buf];
	memregl[0x4058>>2] |= 0x10;
	fb_work_buf++;
	if (fb_work_buf >= buf_count)
		fb_work_buf = 0;
	g_screen_ptr = gp2x_screens[fb_work_buf];
}

static void gp2x_video_flip_(void)
{
	pollux_video_flip(fb_buf_count);
}

/* doulblebuffered flip */
static void gp2x_video_flip2_(void)
{
	pollux_video_flip(2);
}

static void gp2x_video_changemode_ll_(int bpp)
{
	static int prev_bpp = 0;
	int code = 0, bytes = 2;
	int rot_cmd[2] = { 0, 0 };
	unsigned int r;
	char buff[32];
	int ret;

	if (bpp == prev_bpp)
		return;
	prev_bpp = bpp;

	printf("changemode: %dbpp rot=%d\n", abs(bpp), bpp < 0);

	/* negative bpp means rotated mode */
	rot_cmd[0] = (bpp < 0) ? 6 : 5;
	ret = ioctl(fbdev, _IOW('D', 90, int[2]), rot_cmd);
	if (ret < 0)
		perror("rot ioctl failed");
	memregl[0x4004>>2] = (bpp < 0) ? 0x013f00ef : 0x00ef013f;
	memregl[0x4000>>2] |= 1 << 3;

	/* the above ioctl resets LCD timings, so set them here */
	snprintf(buff, sizeof(buff), "POLLUX_LCD_TIMINGS_%s", last_pal_setting ? "PAL" : "NTSC");
	pollux_set_fromenv(buff);

	switch (abs(bpp))
	{
		case 8:
			code = 0x443a;
			bytes = 1;
			break;

		case 15:
		case 16:
			code = 0x4432;
			bytes = 2;
			break;

		default:
			printf("unhandled bpp request: %d\n", abs(bpp));
			return;
	}

	memregl[0x405c>>2] = bytes;
	memregl[0x4060>>2] = bytes * (bpp < 0 ? 240 : 320);

	r = memregl[0x4058>>2];
	r = (r & 0xffff) | (code << 16) | 0x10;
	memregl[0x4058>>2] = r;
}

static void gp2x_video_setpalette_(int *pal, int len)
{
	/* pollux palette is 16bpp only.. */
	int i;
	for (i = 0; i < len; i++)
	{
		int c = pal[i];
		c = ((c >> 8) & 0xf800) | ((c >> 5) & 0x07c0) | ((c >> 3) & 0x001f);
		memregl[0x4070>>2] = (i << 24) | c;
	}
}

static void gp2x_video_RGB_setscaling_(int ln_offs, int W, int H)
{
	/* maybe a job for 3d hardware? */
}

static void gp2x_video_wait_vsync_(void)
{
	while (!(memregl[0x308c>>2] & (1 << 10)))
		spend_cycles(128);
	memregl[0x308c>>2] |= 1 << 10;
}

/* CPU clock */
static void gp2x_set_cpuclk_(unsigned int mhz)
{
	char buff[24];
	snprintf(buff, sizeof(buff), "cpuclk=%u", mhz);
	pollux_set(memregs, buff);

	cpuclk_was_changed = 1;
}

/* RAM timings */
static void set_ram_timings_(void)
{
	pollux_set_fromenv("POLLUX_RAM_TIMINGS");
}

static void unset_ram_timings_(void)
{
	int i;

	memregs[0x14802>>1] = memtimex_old[0];
	memregs[0x14804>>1] = memtimex_old[1] | 0x8000;

	for (i = 0; i < 0x100000; i++)
		if (!(memregs[0x14804>>1] & 0x8000))
			break;

	printf("RAM timings reset to startup values.\n");
}

/* LCD refresh */
static void set_lcd_custom_rate_(int is_pal)
{
	/* just remember PAL/NTSC. We always set timings in _changemode_ll() */
	last_pal_setting = is_pal;
}

static void unset_lcd_custom_rate_(void)
{
}

static void set_lcd_gamma_(int g100, int A_SNs_curve)
{
	/* hm, the LCD possibly can do it (but not POLLUX) */
}

static int gp2x_read_battery_(void)
{
	unsigned short magic_val = 0;

	if (battdev < 0)
		return -1;
	if (read(battdev, &magic_val, sizeof(magic_val)) != sizeof(magic_val))
		return -1;
	switch (magic_val) {
	default:
	case 1:	return 100;
	case 2: return 66;
	case 3: return 40;
	case 4: return 0;
	}
}

#define TIMER_BASE3 0x1980
#define TIMER_REG(x) memregl[(TIMER_BASE3 + x) >> 2]

static unsigned int gp2x_get_ticks_us_(void)
{
	TIMER_REG(0x08) = 0x4b;  /* run timer, latch value */
	return TIMER_REG(0);
}

static unsigned int gp2x_get_ticks_ms_(void)
{
	/* approximate /= 1000 */
	unsigned long long v64;
	v64 = (unsigned long long)gp2x_get_ticks_us_() * 4294968;
	return v64 >> 32;
}

static void timer_cleanup(void)
{
	TIMER_REG(0x40) = 0x0c;	/* be sure clocks are on */
	TIMER_REG(0x08) = 0x23;	/* stop the timer, clear irq in case it's pending */
	TIMER_REG(0x00) = 0;	/* clear counter */
	TIMER_REG(0x40) = 0;	/* clocks off */
	TIMER_REG(0x44) = 0;	/* dividers back to default */
}

/* note: both PLLs are programmed the same way,
 * the databook incorrectly states that PLL1 differs */
static int decode_pll(unsigned int reg)
{
	long long v;
	int p, m, s;

	p = (reg >> 18) & 0x3f;
	m = (reg >> 8) & 0x3ff;
	s = reg & 0xff;

	if (p == 0)
		p = 1;

	v = 27000000; // master clock
	v = v * m / (p << s);
	return v;
}

int pollux_get_real_snd_rate(int req_rate)
{
	int clk0_src, clk1_src, rate, div;

	clk0_src = (memregl[0xdbc4>>2] >> 1) & 7;
	clk1_src = (memregl[0xdbc8>>2] >> 1) & 7;
	if (clk0_src > 1 || clk1_src != 7) {
		fprintf(stderr, "get_real_snd_rate: bad clk sources: %d %d\n", clk0_src, clk1_src);
		return req_rate;
	}

	rate = decode_pll(clk0_src ? memregl[0xf008>>2] : memregl[0xf004>>2]);

	// apply divisors
	div = ((memregl[0xdbc4>>2] >> 4) & 0x3f) + 1;
	rate /= div;
	div = ((memregl[0xdbc8>>2] >> 4) & 0x3f) + 1;
	rate /= div;
	rate /= 64;

	//printf("rate %d\n", rate);
	rate -= rate * timer_drift / 1000000;
	printf("adjusted rate: %d\n", rate);

	if (rate < 8000-1000 || rate > 44100+1000) {
		fprintf(stderr, "get_real_snd_rate: got bad rate: %d\n", rate);
		return req_rate;
	}

	return rate;
}

void pollux_init(void)
{
	struct fb_fix_screeninfo fbfix;
	int i, ret, rate, timer_div;

	memdev = open("/dev/mem", O_RDWR);
	if (memdev == -1) {
		perror("open(/dev/mem) failed");
		exit(1);
	}

	memregs	= mmap(0, 0x20000, PROT_READ|PROT_WRITE, MAP_SHARED, memdev, 0xc0000000);
	if (memregs == MAP_FAILED) {
		perror("mmap(memregs) failed");
		exit(1);
	}
	memregl = (volatile void *)memregs;

	fbdev = open("/dev/fb0", O_RDWR);
	if (fbdev < 0) {
		perror("can't open fbdev");
		exit(1);
	}

	ret = ioctl(fbdev, FBIOGET_FSCREENINFO, &fbfix);
	if (ret == -1) {
		perror("ioctl(fbdev) failed");
		exit(1);
	}

	printf("framebuffer: \"%s\" @ %08lx\n", fbfix.id, fbfix.smem_start);
	fb_paddr[0] = fbfix.smem_start;

	gp2x_screens[0] = mmap(0, 320*240*2*fb_buf_count, PROT_READ|PROT_WRITE,
			MAP_SHARED, memdev, fb_paddr[0]);
	if (gp2x_screens[0] == MAP_FAILED)
	{
		perror("mmap(gp2x_screens) failed");
		exit(1);
	}
	memset(gp2x_screens[0], 0, 320*240*2*fb_buf_count);

	printf("  %p -> %08x\n", gp2x_screens[0], fb_paddr[0]);
	for (i = 1; i < fb_buf_count; i++)
	{
		fb_paddr[i] = fb_paddr[i-1] + 320*240*2;
		gp2x_screens[i] = (char *)gp2x_screens[i-1] + 320*240*2;
		printf("  %p -> %08x\n", gp2x_screens[i], fb_paddr[i]);
	}
	fb_work_buf = 0;
	g_screen_ptr = gp2x_screens[0];

	battdev = open("/dev/pollux_batt", O_RDONLY);
	if (battdev < 0)
		perror("Warning: could't open pollux_batt");

	/* find what PLL1 runs at, for the timer */
	rate = decode_pll(memregl[0xf008>>2]);
	printf("PLL1 @ %dHz\n", rate);

	/* setup timer */
	timer_div = (rate + 500000) / 1000000;
	if (1 <= timer_div && timer_div <= 256) {
		timer_drift = (rate - (timer_div * 1000000)) / timer_div;

		if (TIMER_REG(0x08) & 8) {
			fprintf(stderr, "warning: timer in use, overriding!\n");
			timer_cleanup();
		}

		TIMER_REG(0x44) = ((timer_div - 1) << 4) | 2; /* using PLL1, divide by it's rate */
		TIMER_REG(0x40) = 0x0c;  /* clocks on */
		TIMER_REG(0x08) = 0x6b;  /* run timer, clear irq, latch value */

		gp2x_get_ticks_ms = gp2x_get_ticks_ms_;
		gp2x_get_ticks_us = gp2x_get_ticks_us_;
	}
	else {
		fprintf(stderr, "warning: could not make use of timer\n");

		// those functions are actually not good at all on Wiz kernel
		gp2x_get_ticks_ms = plat_get_ticks_ms_good;
		gp2x_get_ticks_us = plat_get_ticks_us_good;
	}

	pllsetreg0_old = memregl[0xf004>>2];
	memtimex_old[0] = memregs[0x14802>>1];
	memtimex_old[1] = memregs[0x14804>>1];

	gp2x_video_flip = gp2x_video_flip_;
	gp2x_video_flip2 = gp2x_video_flip2_;
	gp2x_video_changemode_ll = gp2x_video_changemode_ll_;
	gp2x_video_setpalette = gp2x_video_setpalette_;
	gp2x_video_RGB_setscaling = gp2x_video_RGB_setscaling_;
	gp2x_video_wait_vsync = gp2x_video_wait_vsync_;

	/* some firmwares have sys clk on PLL0, we can't adjust CPU clock
	 * by reprogramming the PLL0 then, as it overclocks system bus */
	if ((memregl[0xf000>>2] & 0x03000030) == 0x01000000)
		gp2x_set_cpuclk = gp2x_set_cpuclk_;
	else {
		fprintf(stderr, "unexpected PLL config (%08x), overclocking disabled\n",
			memregl[0xf000>>2]);
		gp2x_set_cpuclk = NULL;
	}

	set_lcd_custom_rate = set_lcd_custom_rate_;
	unset_lcd_custom_rate = unset_lcd_custom_rate_;
	set_lcd_gamma = set_lcd_gamma_;

	set_ram_timings = set_ram_timings_;
	unset_ram_timings = unset_ram_timings_;
	gp2x_read_battery = gp2x_read_battery_;
}

void pollux_finish(void)
{
	/* switch to default fb mem, turn portrait off */
	memregl[0x406C>>2] = fb_paddr[0];
	memregl[0x4058>>2] |= 0x10;
	close(fbdev);

	gp2x_video_changemode_ll_(16);
	unset_ram_timings_();
	if (cpuclk_was_changed) {
		memregl[0xf004>>2] = pllsetreg0_old;
		memregl[0xf07c>>2] |= 0x8000;
	}
	timer_cleanup();

	munmap((void *)memregs, 0x20000);
	close(memdev);
	if (battdev >= 0)
		close(battdev);
}