// SPDX-License-Identifier: GPL-2.0
#include <linux/console.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/screen_info.h>
#include <linux/usb/ch9.h>
#include <linux/pci_regs.h>
#include <linux/pci_ids.h>
#include <linux/errno.h>
#include <linux/pgtable.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/fcntl.h>
#include <asm/setup.h>
#include <xen/hvc-console.h>
#include <asm/pci-direct.h>
#include <asm/fixmap.h>
#include <linux/usb/ehci_def.h>
#include <linux/usb/xhci-dbgp.h>
#include <asm/pci_x86.h>

/* Simple VGA output */
#define VGABASE         (__ISA_IO_base + 0xb8000)

static int max_ypos = 25, max_xpos = 80;
static int current_ypos = 25, current_xpos;

static void early_vga_write(struct console *con, const char *str, unsigned n)
{
        char c;
        int  i, k, j;

        while ((c = *str++) != '\0' && n-- > 0) {
                if (current_ypos >= max_ypos) {
                        /* scroll 1 line up */
                        for (k = 1, j = 0; k < max_ypos; k++, j++) {
                                for (i = 0; i < max_xpos; i++) {
                                        writew(readw(VGABASE+2*(max_xpos*k+i)),
                                               VGABASE + 2*(max_xpos*j + i));
                                }
                        }
                        for (i = 0; i < max_xpos; i++)
                                writew(0x720, VGABASE + 2*(max_xpos*j + i));
                        current_ypos = max_ypos-1;
                }
#ifdef CONFIG_KGDB_KDB
                if (c == '\b') {
                        if (current_xpos > 0)
                                current_xpos--;
                } else if (c == '\r') {
                        current_xpos = 0;
                } else
#endif
                if (c == '\n') {
                        current_xpos = 0;
                        current_ypos++;
                } else if (c != '\r')  {
                        writew(((0x7 << 8) | (unsigned short) c),
                               VGABASE + 2*(max_xpos*current_ypos +
                                                current_xpos++));
                        if (current_xpos >= max_xpos) {
                                current_xpos = 0;
                                current_ypos++;
                        }
                }
        }
}

static struct console early_vga_console = {
        .name =         "earlyvga",
        .write =        early_vga_write,
        .flags =        CON_PRINTBUFFER,
        .index =        -1,
};

/* Serial functions loosely based on a similar package from Klaus P. Gerlicher */

static unsigned long early_serial_base = 0x3f8;  /* ttyS0 */

#define XMTRDY          0x20

#define DLAB            0x80

#define TXR             0       /*  Transmit register (WRITE) */
#define RXR             0       /*  Receive register  (READ)  */
#define IER             1       /*  Interrupt Enable          */
#define IIR             2       /*  Interrupt ID              */
#define FCR             2       /*  FIFO control              */
#define LCR             3       /*  Line control              */
#define MCR             4       /*  Modem control             */
#define LSR             5       /*  Line Status               */
#define MSR             6       /*  Modem Status              */
#define DLL             0       /*  Divisor Latch Low         */
#define DLH             1       /*  Divisor latch High        */

static unsigned int io_serial_in(unsigned long addr, int offset)
{
        return inb(addr + offset);
}

static void io_serial_out(unsigned long addr, int offset, int value)
{
        outb(value, addr + offset);
}

static unsigned int (*serial_in)(unsigned long addr, int offset) = io_serial_in;
static void (*serial_out)(unsigned long addr, int offset, int value) = io_serial_out;

static int early_serial_putc(unsigned char ch)
{
        unsigned timeout = 0xffff;

        while ((serial_in(early_serial_base, LSR) & XMTRDY) == 0 && --timeout)
                cpu_relax();
        serial_out(early_serial_base, TXR, ch);
        return timeout ? 0 : -1;
}

static void early_serial_write(struct console *con, const char *s, unsigned n)
{
        while (*s && n-- > 0) {
                if (*s == '\n')
                        early_serial_putc('\r');
                early_serial_putc(*s);
                s++;
        }
}

static __init void early_serial_hw_init(unsigned divisor)
{
        unsigned char c;

        serial_out(early_serial_base, LCR, 0x3);        /* 8n1 */
        serial_out(early_serial_base, IER, 0);  /* no interrupt */
        serial_out(early_serial_base, FCR, 0);  /* no fifo */
        serial_out(early_serial_base, MCR, 0x3);        /* DTR + RTS */

        c = serial_in(early_serial_base, LCR);
        serial_out(early_serial_base, LCR, c | DLAB);
        serial_out(early_serial_base, DLL, divisor & 0xff);
        serial_out(early_serial_base, DLH, (divisor >> 8) & 0xff);
        serial_out(early_serial_base, LCR, c & ~DLAB);
}

#define DEFAULT_BAUD 9600

static __init void early_serial_init(char *s)
{
        unsigned divisor;
        unsigned long baud = DEFAULT_BAUD;
        char *e;

        if (*s == ',')
                ++s;

        if (*s) {
                unsigned port;
                if (!strncmp(s, "0x", 2)) {
                        early_serial_base = simple_strtoul(s, &e, 16);
                } else {
                        static const int __initconst bases[] = { 0x3f8, 0x2f8 };

                        if (!strncmp(s, "ttyS", 4))
                                s += 4;
                        port = simple_strtoul(s, &e, 10);
                        if (port > 1 || s == e)
                                port = 0;
                        early_serial_base = bases[port];
                }
                s += strcspn(s, ",");
                if (*s == ',')
                        s++;
        }

        if (*s) {
                baud = simple_strtoull(s, &e, 0);

                if (baud == 0 || s == e)
                        baud = DEFAULT_BAUD;
        }

        /* Convert from baud to divisor value */
        divisor = 115200 / baud;

        /* These will always be IO based ports */
        serial_in = io_serial_in;
        serial_out = io_serial_out;

        /* Set up the HW */
        early_serial_hw_init(divisor);
}

#ifdef CONFIG_PCI
static void mem32_serial_out(unsigned long addr, int offset, int value)
{
        u32 __iomem *vaddr = (u32 __iomem *)addr;
        /* shift implied by pointer type */
        writel(value, vaddr + offset);
}

static unsigned int mem32_serial_in(unsigned long addr, int offset)
{
        u32 __iomem *vaddr = (u32 __iomem *)addr;
        /* shift implied by pointer type */
        return readl(vaddr + offset);
}

/*
 * early_pci_serial_init()
 *
 * This function is invoked when the early_printk param starts with "pciserial"
 * The rest of the param should be "[force],B:D.F,baud", where B, D & F describe
 * the location of a PCI device that must be a UART device. "force" is optional
 * and overrides the use of an UART device with a wrong PCI class code.
 */
static __init void early_pci_serial_init(char *s)
{
        unsigned divisor;
        unsigned long baud = DEFAULT_BAUD;
        u8 bus, slot, func;
        u32 classcode, bar0;
        u16 cmdreg;
        char *e;
        int force = 0;

        if (*s == ',')
                ++s;

        if (*s == 0)
                return;

        /* Force the use of an UART device with wrong class code */
        if (!strncmp(s, "force,", 6)) {
                force = 1;
                s += 6;
        }

        /*
         * Part the param to get the BDF values
         */
        bus = (u8)simple_strtoul(s, &e, 16);
        s = e;
        if (*s != ':')
                return;
        ++s;
        slot = (u8)simple_strtoul(s, &e, 16);
        s = e;
        if (*s != '.')
                return;
        ++s;
        func = (u8)simple_strtoul(s, &e, 16);
        s = e;

        /* A baud might be following */
        if (*s == ',')
                s++;

        /*
         * Find the device from the BDF
         */
        cmdreg = read_pci_config(bus, slot, func, PCI_COMMAND);
        classcode = read_pci_config(bus, slot, func, PCI_CLASS_REVISION);
        bar0 = read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_0);

        /*
         * Verify it is a UART type device
         */
        if (((classcode >> 16 != PCI_CLASS_COMMUNICATION_MODEM) &&
             (classcode >> 16 != PCI_CLASS_COMMUNICATION_SERIAL)) ||
           (((classcode >> 8) & 0xff) != 0x02)) /* 16550 I/F at BAR0 */ {
                if (!force)
                        return;
        }

        /*
         * Determine if it is IO or memory mapped
         */
        if (bar0 & 0x01) {
                /* it is IO mapped */
                serial_in = io_serial_in;
                serial_out = io_serial_out;
                early_serial_base = bar0&0xfffffffc;
                write_pci_config(bus, slot, func, PCI_COMMAND,
                                                cmdreg|PCI_COMMAND_IO);
        } else {
                /* It is memory mapped - assume 32-bit alignment */
                serial_in = mem32_serial_in;
                serial_out = mem32_serial_out;
                /* WARNING! assuming the address is always in the first 4G */
                early_serial_base =
                        (unsigned long)early_ioremap(bar0 & 0xfffffff0, 0x10);
                write_pci_config(bus, slot, func, PCI_COMMAND,
                                                cmdreg|PCI_COMMAND_MEMORY);
        }

        /*
         * Initialize the hardware
         */
        if (*s) {
                if (strcmp(s, "nocfg") == 0)
                        /* Sometimes, we want to leave the UART alone
                         * and assume the BIOS has set it up correctly.
                         * "nocfg" tells us this is the case, and we
                         * should do no more setup.
                         */
                        return;
                if (kstrtoul(s, 0, &baud) < 0 || baud == 0)
                        baud = DEFAULT_BAUD;
        }

        /* Convert from baud to divisor value */
        divisor = 115200 / baud;

        /* Set up the HW */
        early_serial_hw_init(divisor);
}
#endif

static struct console early_serial_console = {
        .name =         "earlyser",
        .write =        early_serial_write,
        .flags =        CON_PRINTBUFFER,
        .index =        -1,
};

static void early_console_register(struct console *con, int keep_early)
{
        if (con->index != -1) {
                printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
                       con->name);
                return;
        }
        early_console = con;
        if (keep_early)
                early_console->flags &= ~CON_BOOT;
        else
                early_console->flags |= CON_BOOT;
        register_console(early_console);
}

static int __init setup_early_printk(char *buf)
{
        int keep;

        if (!buf)
                return 0;

        if (early_console)
                return 0;

        keep = (strstr(buf, "keep") != NULL);

        while (*buf != '\0') {
                if (!strncmp(buf, "serial", 6)) {
                        buf += 6;
                        early_serial_init(buf);
                        early_console_register(&early_serial_console, keep);
                        if (!strncmp(buf, ",ttyS", 5))
                                buf += 5;
                }
                if (!strncmp(buf, "ttyS", 4)) {
                        early_serial_init(buf + 4);
                        early_console_register(&early_serial_console, keep);
                }
#ifdef CONFIG_PCI
                if (!strncmp(buf, "pciserial", 9)) {
                        early_pci_serial_init(buf + 9);
                        early_console_register(&early_serial_console, keep);
                        buf += 9; /* Keep from match the above "serial" */
                }
#endif
                if (!strncmp(buf, "vga", 3) &&
                    boot_params.screen_info.orig_video_isVGA == 1) {
                        max_xpos = boot_params.screen_info.orig_video_cols;
                        max_ypos = boot_params.screen_info.orig_video_lines;
                        current_ypos = boot_params.screen_info.orig_y;
                        early_console_register(&early_vga_console, keep);
                }
#ifdef CONFIG_EARLY_PRINTK_DBGP
                if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
                        early_console_register(&early_dbgp_console, keep);
#endif
#ifdef CONFIG_HVC_XEN
                if (!strncmp(buf, "xen", 3))
                        early_console_register(&xenboot_console, keep);
#endif
#ifdef CONFIG_EARLY_PRINTK_USB_XDBC
                if (!strncmp(buf, "xdbc", 4))
                        early_xdbc_parse_parameter(buf + 4);
#endif

                buf++;
        }
        return 0;
}

early_param("earlyprintk", setup_early_printk);