// SPDX-License-Identifier: GPL-2.0-only
/* Low-level parallel port routines for the Atari builtin port
 *
 * Author: Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>
 *
 * Based on parport_amiga.c.
 *
 * The built-in Atari parallel port provides one port at a fixed address
 * with 8 output data lines (D0 - D7), 1 output control line (STROBE)
 * and 1 input status line (BUSY) able to cause an interrupt.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/parport.h>
#include <linux/interrupt.h>
#include <asm/setup.h>
#include <asm/atarihw.h>
#include <asm/irq.h>
#include <asm/atariints.h>

static struct parport *this_port;

static unsigned char
parport_atari_read_data(struct parport *p)
{
        unsigned long flags;
        unsigned char data;

        local_irq_save(flags);
        sound_ym.rd_data_reg_sel = 15;
        data = sound_ym.rd_data_reg_sel;
        local_irq_restore(flags);
        return data;
}

static void
parport_atari_write_data(struct parport *p, unsigned char data)
{
        unsigned long flags;

        local_irq_save(flags);
        sound_ym.rd_data_reg_sel = 15;
        sound_ym.wd_data = data;
        local_irq_restore(flags);
}

static unsigned char
parport_atari_read_control(struct parport *p)
{
        unsigned long flags;
        unsigned char control = 0;

        local_irq_save(flags);
        sound_ym.rd_data_reg_sel = 14;
        if (!(sound_ym.rd_data_reg_sel & (1 << 5)))
                control = PARPORT_CONTROL_STROBE;
        local_irq_restore(flags);
        return control;
}

static void
parport_atari_write_control(struct parport *p, unsigned char control)
{
        unsigned long flags;

        local_irq_save(flags);
        sound_ym.rd_data_reg_sel = 14;
        if (control & PARPORT_CONTROL_STROBE)
                sound_ym.wd_data = sound_ym.rd_data_reg_sel & ~(1 << 5);
        else
                sound_ym.wd_data = sound_ym.rd_data_reg_sel | (1 << 5);
        local_irq_restore(flags);
}

static unsigned char
parport_atari_frob_control(struct parport *p, unsigned char mask,
                           unsigned char val)
{
        unsigned char old = parport_atari_read_control(p);
        parport_atari_write_control(p, (old & ~mask) ^ val);
        return old;
}

static unsigned char
parport_atari_read_status(struct parport *p)
{
        return ((st_mfp.par_dt_reg & 1 ? 0 : PARPORT_STATUS_BUSY) |
                PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR);
}

static void
parport_atari_init_state(struct pardevice *d, struct parport_state *s)
{
}

static void
parport_atari_save_state(struct parport *p, struct parport_state *s)
{
}

static void
parport_atari_restore_state(struct parport *p, struct parport_state *s)
{
}

static void
parport_atari_enable_irq(struct parport *p)
{
        enable_irq(IRQ_MFP_BUSY);
}

static void
parport_atari_disable_irq(struct parport *p)
{
        disable_irq(IRQ_MFP_BUSY);
}

static void
parport_atari_data_forward(struct parport *p)
{
        unsigned long flags;

        local_irq_save(flags);
        /* Soundchip port B as output. */
        sound_ym.rd_data_reg_sel = 7;
        sound_ym.wd_data = sound_ym.rd_data_reg_sel | 0x40;
        local_irq_restore(flags);
}

static void
parport_atari_data_reverse(struct parport *p)
{
}

static struct parport_operations parport_atari_ops = {
        .write_data     = parport_atari_write_data,
        .read_data      = parport_atari_read_data,

        .write_control  = parport_atari_write_control,
        .read_control   = parport_atari_read_control,
        .frob_control   = parport_atari_frob_control,

        .read_status    = parport_atari_read_status,

        .enable_irq     = parport_atari_enable_irq,
        .disable_irq    = parport_atari_disable_irq,

        .data_forward   = parport_atari_data_forward,
        .data_reverse   = parport_atari_data_reverse,

        .init_state     = parport_atari_init_state,
        .save_state     = parport_atari_save_state,
        .restore_state  = parport_atari_restore_state,

        .epp_write_data = parport_ieee1284_epp_write_data,
        .epp_read_data  = parport_ieee1284_epp_read_data,
        .epp_write_addr = parport_ieee1284_epp_write_addr,
        .epp_read_addr  = parport_ieee1284_epp_read_addr,

        .ecp_write_data = parport_ieee1284_ecp_write_data,
        .ecp_read_data  = parport_ieee1284_ecp_read_data,
        .ecp_write_addr = parport_ieee1284_ecp_write_addr,

        .compat_write_data      = parport_ieee1284_write_compat,
        .nibble_read_data       = parport_ieee1284_read_nibble,
        .byte_read_data         = parport_ieee1284_read_byte,

        .owner          = THIS_MODULE,
};


static int __init parport_atari_init(void)
{
        struct parport *p;
        unsigned long flags;

        if (MACH_IS_ATARI) {
                local_irq_save(flags);
                /* Soundchip port A/B as output. */
                sound_ym.rd_data_reg_sel = 7;
                sound_ym.wd_data = (sound_ym.rd_data_reg_sel & 0x3f) | 0xc0;
                /* STROBE high. */
                sound_ym.rd_data_reg_sel = 14;
                sound_ym.wd_data = sound_ym.rd_data_reg_sel | (1 << 5);
                local_irq_restore(flags);
                /* MFP port I0 as input. */
                st_mfp.data_dir &= ~1;
                /* MFP port I0 interrupt on high->low edge. */
                st_mfp.active_edge &= ~1;
                p = parport_register_port((unsigned long)&sound_ym.wd_data,
                                          IRQ_MFP_BUSY, PARPORT_DMA_NONE,
                                          &parport_atari_ops);
                if (!p)
                        return -ENODEV;
                if (request_irq(IRQ_MFP_BUSY, parport_irq_handler, 0, p->name,
                                p)) {
                        parport_put_port (p);
                        return -ENODEV;
                }

                this_port = p;
                pr_info("%s: Atari built-in port using irq\n", p->name);
                parport_announce_port (p);

                return 0;
        }
        return -ENODEV;
}

static void __exit parport_atari_exit(void)
{
        parport_remove_port(this_port);
        if (this_port->irq != PARPORT_IRQ_NONE)
                free_irq(IRQ_MFP_BUSY, this_port);
        parport_put_port(this_port);
}

MODULE_AUTHOR("Andreas Schwab");
MODULE_DESCRIPTION("Parport Driver for Atari builtin Port");
MODULE_LICENSE("GPL");

module_init(parport_atari_init)
module_exit(parport_atari_exit)