/*
 * linux/arch/m68k/atari/debug.c
 *
 * Atari debugging and serial console stuff
 *
 * Assembled of parts of former atari/config.c 97-12-18 by Roman Hodek
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

#include <linux/types.h>
#include <linux/tty.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/module.h>

#include <asm/atarihw.h>
#include <asm/atariints.h>

/* Can be set somewhere, if a SCC master reset has already be done and should
 * not be repeated; used by kgdb */
int atari_SCC_reset_done;
EXPORT_SYMBOL(atari_SCC_reset_done);

static struct console atari_console_driver = {
        .name   = "debug",
        .flags  = CON_PRINTBUFFER,
        .index  = -1,
};


static inline void ata_mfp_out(char c)
{
        while (!(st_mfp.trn_stat & 0x80))       /* wait for tx buf empty */
                barrier();
        st_mfp.usart_dta = c;
}

static void atari_mfp_console_write(struct console *co, const char *str,
                                    unsigned int count)
{
        while (count--) {
                if (*str == '\n')
                        ata_mfp_out('\r');
                ata_mfp_out(*str++);
        }
}

static inline void ata_scc_out(char c)
{
        do {
                MFPDELAY();
        } while (!(atari_scc.cha_b_ctrl & 0x04)); /* wait for tx buf empty */
        MFPDELAY();
        atari_scc.cha_b_data = c;
}

static void atari_scc_console_write(struct console *co, const char *str,
                                    unsigned int count)
{
        while (count--) {
                if (*str == '\n')
                        ata_scc_out('\r');
                ata_scc_out(*str++);
        }
}

static inline void ata_midi_out(char c)
{
        while (!(acia.mid_ctrl & ACIA_TDRE))    /* wait for tx buf empty */
                barrier();
        acia.mid_data = c;
}

static void atari_midi_console_write(struct console *co, const char *str,
                                     unsigned int count)
{
        while (count--) {
                if (*str == '\n')
                        ata_midi_out('\r');
                ata_midi_out(*str++);
        }
}

static int ata_par_out(char c)
{
        unsigned char tmp;
        /* This a some-seconds timeout in case no printer is connected */
        unsigned long i = loops_per_jiffy > 1 ? loops_per_jiffy : 10000000/HZ;

        while ((st_mfp.par_dt_reg & 1) && --i) /* wait for BUSY == L */
                ;
        if (!i)
                return 0;

        sound_ym.rd_data_reg_sel = 15;  /* select port B */
        sound_ym.wd_data = c;           /* put char onto port */
        sound_ym.rd_data_reg_sel = 14;  /* select port A */
        tmp = sound_ym.rd_data_reg_sel;
        sound_ym.wd_data = tmp & ~0x20; /* set strobe L */
        MFPDELAY();                     /* wait a bit */
        sound_ym.wd_data = tmp | 0x20;  /* set strobe H */
        return 1;
}

static void atari_par_console_write(struct console *co, const char *str,
                                    unsigned int count)
{
        static int printer_present = 1;

        if (!printer_present)
                return;

        while (count--) {
                if (*str == '\n') {
                        if (!ata_par_out('\r')) {
                                printer_present = 0;
                                return;
                        }
                }
                if (!ata_par_out(*str++)) {
                        printer_present = 0;
                        return;
                }
        }
}

#if 0
int atari_mfp_console_wait_key(struct console *co)
{
        while (!(st_mfp.rcv_stat & 0x80))       /* wait for rx buf filled */
                barrier();
        return st_mfp.usart_dta;
}

int atari_scc_console_wait_key(struct console *co)
{
        do {
                MFPDELAY();
        } while (!(atari_scc.cha_b_ctrl & 0x01)); /* wait for rx buf filled */
        MFPDELAY();
        return atari_scc.cha_b_data;
}

int atari_midi_console_wait_key(struct console *co)
{
        while (!(acia.mid_ctrl & ACIA_RDRF)) /* wait for rx buf filled */
                barrier();
        return acia.mid_data;
}
#endif

/*
 * The following two functions do a quick'n'dirty initialization of the MFP or
 * SCC serial ports. They're used by the debugging interface, kgdb, and the
 * serial console code.
 */
static void __init atari_init_mfp_port(int cflag)
{
        /*
         * timer values for 1200...115200 bps; > 38400 select 110, 134, or 150
         * bps, resp., and work only correct if there's a RSVE or RSSPEED
         */
        static int baud_table[9] = { 16, 11, 8, 4, 2, 1, 175, 143, 128 };
        int baud = cflag & CBAUD;
        int parity = (cflag & PARENB) ? ((cflag & PARODD) ? 0x04 : 0x06) : 0;
        int csize = ((cflag & CSIZE) == CS7) ? 0x20 : 0x00;

        if (cflag & CBAUDEX)
                baud += B38400;
        if (baud < B1200 || baud > B38400+2)
                baud = B9600;           /* use default 9600bps for non-implemented rates */
        baud -= B1200;                  /* baud_table[] starts at 1200bps */

        st_mfp.trn_stat &= ~0x01;       /* disable TX */
        st_mfp.usart_ctr = parity | csize | 0x88; /* 1:16 clk mode, 1 stop bit */
        st_mfp.tim_ct_cd &= 0x70;       /* stop timer D */
        st_mfp.tim_dt_d = baud_table[baud];
        st_mfp.tim_ct_cd |= 0x01;       /* start timer D, 1:4 */
        st_mfp.trn_stat |= 0x01;        /* enable TX */
}

#define SCC_WRITE(reg, val)                             \
        do {                                            \
                atari_scc.cha_b_ctrl = (reg);           \
                MFPDELAY();                             \
                atari_scc.cha_b_ctrl = (val);           \
                MFPDELAY();                             \
        } while (0)

/* loops_per_jiffy isn't initialized yet, so we can't use udelay(). This does a
 * delay of ~ 60us. */
#define LONG_DELAY()                                    \
        do {                                            \
                int i;                                  \
                for (i = 100; i > 0; --i)               \
                        MFPDELAY();                     \
        } while (0)

static void __init atari_init_scc_port(int cflag)
{
        static int clksrc_table[9] =
                /* reg 11: 0x50 = BRG, 0x00 = RTxC, 0x28 = TRxC */
                { 0x50, 0x50, 0x50, 0x50, 0x50, 0x50, 0x50, 0x00, 0x00 };
        static int brgsrc_table[9] =
                /* reg 14: 0 = RTxC, 2 = PCLK */
                { 2, 2, 2, 2, 2, 2, 0, 2, 2 };
        static int clkmode_table[9] =
                /* reg 4: 0x40 = x16, 0x80 = x32, 0xc0 = x64 */
                { 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0xc0, 0x80 };
        static int div_table[9] =
                /* reg12 (BRG low) */
                { 208, 138, 103, 50, 24, 11, 1, 0, 0 };

        int baud = cflag & CBAUD;
        int clksrc, clkmode, div, reg3, reg5;

        if (cflag & CBAUDEX)
                baud += B38400;
        if (baud < B1200 || baud > B38400+2)
                baud = B9600;           /* use default 9600bps for non-implemented rates */
        baud -= B1200;                  /* tables starts at 1200bps */

        clksrc  = clksrc_table[baud];
        clkmode = clkmode_table[baud];
        div     = div_table[baud];
        if (ATARIHW_PRESENT(TT_MFP) && baud >= 6) {
                /* special treatment for TT, where rates >= 38400 are done via TRxC */
                clksrc = 0x28;          /* TRxC */
                clkmode = baud == 6 ? 0xc0 :
                          baud == 7 ? 0x80 : /* really 76800bps */
                                      0x40;  /* really 153600bps */
                div = 0;
        }

        reg3 = (cflag & CSIZE) == CS8 ? 0xc0 : 0x40;
        reg5 = (cflag & CSIZE) == CS8 ? 0x60 : 0x20 | 0x82 /* assert DTR/RTS */;

        (void)atari_scc.cha_b_ctrl;     /* reset reg pointer */
        SCC_WRITE(9, 0xc0);             /* reset */
        LONG_DELAY();                   /* extra delay after WR9 access */
        SCC_WRITE(4, (cflag & PARENB) ? ((cflag & PARODD) ? 0x01 : 0x03)
                                      : 0 | 0x04 /* 1 stopbit */ | clkmode);
        SCC_WRITE(3, reg3);
        SCC_WRITE(5, reg5);
        SCC_WRITE(9, 0);                /* no interrupts */
        LONG_DELAY();                   /* extra delay after WR9 access */
        SCC_WRITE(10, 0);               /* NRZ mode */
        SCC_WRITE(11, clksrc);          /* main clock source */
        SCC_WRITE(12, div);             /* BRG value */
        SCC_WRITE(13, 0);               /* BRG high byte */
        SCC_WRITE(14, brgsrc_table[baud]);
        SCC_WRITE(14, brgsrc_table[baud] | (div ? 1 : 0));
        SCC_WRITE(3, reg3 | 1);
        SCC_WRITE(5, reg5 | 8);

        atari_SCC_reset_done = 1;
}

static void __init atari_init_midi_port(int cflag)
{
        int baud = cflag & CBAUD;
        int csize = ((cflag & CSIZE) == CS8) ? 0x10 : 0x00;
        /* warning 7N1 isn't possible! (instead 7O2 is used...) */
        int parity = (cflag & PARENB) ? ((cflag & PARODD) ? 0x0c : 0x08) : 0x04;
        int div;

        /* 4800 selects 7812.5, 115200 selects 500000, all other (incl. 9600 as
         * default) the standard MIDI speed 31250. */
        if (cflag & CBAUDEX)
                baud += B38400;
        if (baud == B4800)
                div = ACIA_DIV64;       /* really 7812.5 bps */
        else if (baud == B38400+2 /* 115200 */)
                div = ACIA_DIV1;        /* really 500 kbps (does that work??) */
        else
                div = ACIA_DIV16;       /* 31250 bps, standard for MIDI */

        /* RTS low, ints disabled */
        acia.mid_ctrl = div | csize | parity |
                    ((atari_switches & ATARI_SWITCH_MIDI) ?
                     ACIA_RHTID : ACIA_RLTID);
}

static int __init atari_debug_setup(char *arg)
{
        bool registered;

        if (!MACH_IS_ATARI)
                return 0;

        if (!strcmp(arg, "ser"))
                /* defaults to ser2 for a Falcon and ser1 otherwise */
                arg = MACH_IS_FALCON ? "ser2" : "ser1";

        registered = !!atari_console_driver.write;
        if (!strcmp(arg, "ser1")) {
                /* ST-MFP Modem1 serial port */
                atari_init_mfp_port(B9600|CS8);
                atari_console_driver.write = atari_mfp_console_write;
        } else if (!strcmp(arg, "ser2")) {
                /* SCC Modem2 serial port */
                atari_init_scc_port(B9600|CS8);
                atari_console_driver.write = atari_scc_console_write;
        } else if (!strcmp(arg, "midi")) {
                /* MIDI port */
                atari_init_midi_port(B9600|CS8);
                atari_console_driver.write = atari_midi_console_write;
        } else if (!strcmp(arg, "par")) {
                /* parallel printer */
                atari_turnoff_irq(IRQ_MFP_BUSY); /* avoid ints */
                sound_ym.rd_data_reg_sel = 7;   /* select mixer control */
                sound_ym.wd_data = 0xff;        /* sound off, ports are output */
                sound_ym.rd_data_reg_sel = 15;  /* select port B */
                sound_ym.wd_data = 0;           /* no char */
                sound_ym.rd_data_reg_sel = 14;  /* select port A */
                sound_ym.wd_data = sound_ym.rd_data_reg_sel | 0x20; /* strobe H */
                atari_console_driver.write = atari_par_console_write;
        }
        if (atari_console_driver.write && !registered)
                register_console(&atari_console_driver);

        return 0;
}

early_param("debug", atari_debug_setup);