// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2016 IBM Corporation.
 */

#include "ops.h"
#include "stdio.h"
#include "io.h"
#include <libfdt.h>
#include "../include/asm/opal-api.h"

/* Global OPAL struct used by opal-call.S */
struct opal {
        u64 base;
        u64 entry;
} opal;

static u32 opal_con_id;

/* see opal-wrappers.S */
int64_t opal_console_write(int64_t term_number, u64 *length, const u8 *buffer);
int64_t opal_console_read(int64_t term_number, uint64_t *length, u8 *buffer);
int64_t opal_console_write_buffer_space(uint64_t term_number, uint64_t *length);
int64_t opal_console_flush(uint64_t term_number);
int64_t opal_poll_events(uint64_t *outstanding_event_mask);

void opal_kentry(unsigned long fdt_addr, void *vmlinux_addr);

static int opal_con_open(void)
{
        /*
         * When OPAL loads the boot kernel it stashes the OPAL base and entry
         * address in r8 and r9 so the kernel can use the OPAL console
         * before unflattening the devicetree. While executing the wrapper will
         * probably trash r8 and r9 so this kentry hook restores them before
         * entering the decompressed kernel.
         */
        platform_ops.kentry = opal_kentry;
        return 0;
}

static void opal_con_putc(unsigned char c)
{
        int64_t rc;
        uint64_t olen, len;

        do {
                rc = opal_console_write_buffer_space(opal_con_id, &olen);
                len = be64_to_cpu(olen);
                if (rc)
                        return;
                opal_poll_events(NULL);
        } while (len < 1);


        olen = cpu_to_be64(1);
        opal_console_write(opal_con_id, &olen, &c);
}

static void opal_con_close(void)
{
        opal_console_flush(opal_con_id);
}

static void opal_init(void)
{
        void *opal_node;

        opal_node = finddevice("/ibm,opal");
        if (!opal_node)
                return;
        if (getprop(opal_node, "opal-base-address", &opal.base, sizeof(u64)) < 0)
                return;
        opal.base = be64_to_cpu(opal.base);
        if (getprop(opal_node, "opal-entry-address", &opal.entry, sizeof(u64)) < 0)
                return;
        opal.entry = be64_to_cpu(opal.entry);
}

int opal_console_init(void *devp, struct serial_console_data *scdp)
{
        opal_init();

        if (devp) {
                int n = getprop(devp, "reg", &opal_con_id, sizeof(u32));
                if (n != sizeof(u32))
                        return -1;
                opal_con_id = be32_to_cpu(opal_con_id);
        } else
                opal_con_id = 0;

        scdp->open = opal_con_open;
        scdp->putc = opal_con_putc;
        scdp->close = opal_con_close;

        return 0;
}