// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * polling mode stateless debugging stuff, originally for NS16550 Serial Ports
 *
 * c 2001 PPC 64 Team, IBM Corp
 */

#include <linux/stdarg.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/console.h>
#include <linux/init.h>
#include <asm/processor.h>
#include <asm/udbg.h>

void (*udbg_putc)(char c);
void (*udbg_flush)(void);
int (*udbg_getc)(void);
int (*udbg_getc_poll)(void);

/*
 * Early debugging facilities. You can enable _one_ of these via .config,
 * if you do so your kernel _will not boot_ on anything else. Be careful.
 */
void __init udbg_early_init(void)
{
#if defined(CONFIG_PPC_EARLY_DEBUG_LPAR)
        /* For LPAR machines that have an HVC console on vterm 0 */
        udbg_init_debug_lpar();
#elif defined(CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI)
        /* For LPAR machines that have an HVSI console on vterm 0 */
        udbg_init_debug_lpar_hvsi();
#elif defined(CONFIG_PPC_EARLY_DEBUG_G5)
        /* For use on Apple G5 machines */
        udbg_init_pmac_realmode();
#elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS_PANEL)
        /* RTAS panel debug */
        udbg_init_rtas_panel();
#elif defined(CONFIG_PPC_EARLY_DEBUG_PAS_REALMODE)
        udbg_init_pas_realmode();
#elif defined(CONFIG_PPC_EARLY_DEBUG_BOOTX)
        udbg_init_btext();
#elif defined(CONFIG_PPC_EARLY_DEBUG_44x)
        /* PPC44x debug */
        udbg_init_44x_as1();
#elif defined(CONFIG_PPC_EARLY_DEBUG_CPM)
        udbg_init_cpm();
#elif defined(CONFIG_PPC_EARLY_DEBUG_USBGECKO)
        udbg_init_usbgecko();
#elif defined(CONFIG_PPC_EARLY_DEBUG_MEMCONS)
        /* In memory console */
        udbg_init_memcons();
#elif defined(CONFIG_PPC_EARLY_DEBUG_EHV_BC)
        udbg_init_ehv_bc();
#elif defined(CONFIG_PPC_EARLY_DEBUG_PS3GELIC)
        udbg_init_ps3gelic();
#elif defined(CONFIG_PPC_EARLY_DEBUG_OPAL_RAW)
        udbg_init_debug_opal_raw();
#elif defined(CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI)
        udbg_init_debug_opal_hvsi();
#elif defined(CONFIG_PPC_EARLY_DEBUG_16550)
        udbg_init_debug_16550();
#endif

#ifdef CONFIG_PPC_EARLY_DEBUG
        console_loglevel = CONSOLE_LOGLEVEL_DEBUG;

        register_early_udbg_console();
#endif
}

/* udbg library, used by xmon et al */
void udbg_puts(const char *s)
{
        if (udbg_putc) {
                char c;

                if (s && *s != '\0') {
                        while ((c = *s++) != '\0')
                                udbg_putc(c);
                }

                if (udbg_flush)
                        udbg_flush();
        }
#if 0
        else {
                printk("%s", s);
        }
#endif
}

int udbg_write(const char *s, int n)
{
        int remain = n;
        char c;

        if (!udbg_putc)
                return 0;

        if (s && *s != '\0') {
                while (((c = *s++) != '\0') && (remain-- > 0)) {
                        udbg_putc(c);
                }
        }

        if (udbg_flush)
                udbg_flush();

        return n - remain;
}

#define UDBG_BUFSIZE 256
void udbg_printf(const char *fmt, ...)
{
        if (udbg_putc) {
                char buf[UDBG_BUFSIZE];
                va_list args;

                va_start(args, fmt);
                vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
                udbg_puts(buf);
                va_end(args);
        }
}

void __init udbg_progress(char *s, unsigned short hex)
{
        udbg_puts(s);
        udbg_puts("\n");
}

/*
 * Early boot console based on udbg
 */
static void udbg_console_write(struct console *con, const char *s,
                unsigned int n)
{
        udbg_write(s, n);
}

static struct console udbg_console = {
        .name   = "udbg",
        .write  = udbg_console_write,
        .flags  = CON_PRINTBUFFER | CON_ENABLED | CON_BOOT | CON_ANYTIME,
        .index  = 0,
};

/*
 * Called by setup_system after ppc_md->probe and ppc_md->early_init.
 * Call it again after setting udbg_putc in ppc_md->setup_arch.
 */
void __init register_early_udbg_console(void)
{
        if (early_console)
                return;

        if (!udbg_putc)
                return;

        if (strstr(boot_command_line, "udbg-immortal")) {
                printk(KERN_INFO "early console immortal !\n");
                udbg_console.flags &= ~CON_BOOT;
        }
        early_console = &udbg_console;
        register_console(&udbg_console);
}

#if 0   /* if you want to use this as a regular output console */
console_initcall(register_udbg_console);
#endif