debug.c

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/*
 * 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)
{
    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";

    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)
        register_console(&atari_console_driver);

    return 0;
}

early_param("debug", atari_debug_setup);