linux/arch/x86/kernel/early_printk.c
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   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/console.h>
   3#include <linux/kernel.h>
   4#include <linux/init.h>
   5#include <linux/string.h>
   6#include <linux/screen_info.h>
   7#include <linux/usb/ch9.h>
   8#include <linux/pci_regs.h>
   9#include <linux/pci_ids.h>
  10#include <linux/errno.h>
  11#include <linux/pgtable.h>
  12#include <asm/io.h>
  13#include <asm/processor.h>
  14#include <asm/fcntl.h>
  15#include <asm/setup.h>
  16#include <xen/hvc-console.h>
  17#include <asm/pci-direct.h>
  18#include <asm/fixmap.h>
  19#include <linux/usb/ehci_def.h>
  20#include <linux/usb/xhci-dbgp.h>
  21#include <asm/pci_x86.h>
  22
  23/* Simple VGA output */
  24#define VGABASE         (__ISA_IO_base + 0xb8000)
  25
  26static int max_ypos = 25, max_xpos = 80;
  27static int current_ypos = 25, current_xpos;
  28
  29static void early_vga_write(struct console *con, const char *str, unsigned n)
  30{
  31        char c;
  32        int  i, k, j;
  33
  34        while ((c = *str++) != '\0' && n-- > 0) {
  35                if (current_ypos >= max_ypos) {
  36                        /* scroll 1 line up */
  37                        for (k = 1, j = 0; k < max_ypos; k++, j++) {
  38                                for (i = 0; i < max_xpos; i++) {
  39                                        writew(readw(VGABASE+2*(max_xpos*k+i)),
  40                                               VGABASE + 2*(max_xpos*j + i));
  41                                }
  42                        }
  43                        for (i = 0; i < max_xpos; i++)
  44                                writew(0x720, VGABASE + 2*(max_xpos*j + i));
  45                        current_ypos = max_ypos-1;
  46                }
  47#ifdef CONFIG_KGDB_KDB
  48                if (c == '\b') {
  49                        if (current_xpos > 0)
  50                                current_xpos--;
  51                } else if (c == '\r') {
  52                        current_xpos = 0;
  53                } else
  54#endif
  55                if (c == '\n') {
  56                        current_xpos = 0;
  57                        current_ypos++;
  58                } else if (c != '\r')  {
  59                        writew(((0x7 << 8) | (unsigned short) c),
  60                               VGABASE + 2*(max_xpos*current_ypos +
  61                                                current_xpos++));
  62                        if (current_xpos >= max_xpos) {
  63                                current_xpos = 0;
  64                                current_ypos++;
  65                        }
  66                }
  67        }
  68}
  69
  70static struct console early_vga_console = {
  71        .name =         "earlyvga",
  72        .write =        early_vga_write,
  73        .flags =        CON_PRINTBUFFER,
  74        .index =        -1,
  75};
  76
  77/* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
  78
  79static unsigned long early_serial_base = 0x3f8;  /* ttyS0 */
  80
  81#define XMTRDY          0x20
  82
  83#define DLAB            0x80
  84
  85#define TXR             0       /*  Transmit register (WRITE) */
  86#define RXR             0       /*  Receive register  (READ)  */
  87#define IER             1       /*  Interrupt Enable          */
  88#define IIR             2       /*  Interrupt ID              */
  89#define FCR             2       /*  FIFO control              */
  90#define LCR             3       /*  Line control              */
  91#define MCR             4       /*  Modem control             */
  92#define LSR             5       /*  Line Status               */
  93#define MSR             6       /*  Modem Status              */
  94#define DLL             0       /*  Divisor Latch Low         */
  95#define DLH             1       /*  Divisor latch High        */
  96
  97static unsigned int io_serial_in(unsigned long addr, int offset)
  98{
  99        return inb(addr + offset);
 100}
 101
 102static void io_serial_out(unsigned long addr, int offset, int value)
 103{
 104        outb(value, addr + offset);
 105}
 106
 107static unsigned int (*serial_in)(unsigned long addr, int offset) = io_serial_in;
 108static void (*serial_out)(unsigned long addr, int offset, int value) = io_serial_out;
 109
 110static int early_serial_putc(unsigned char ch)
 111{
 112        unsigned timeout = 0xffff;
 113
 114        while ((serial_in(early_serial_base, LSR) & XMTRDY) == 0 && --timeout)
 115                cpu_relax();
 116        serial_out(early_serial_base, TXR, ch);
 117        return timeout ? 0 : -1;
 118}
 119
 120static void early_serial_write(struct console *con, const char *s, unsigned n)
 121{
 122        while (*s && n-- > 0) {
 123                if (*s == '\n')
 124                        early_serial_putc('\r');
 125                early_serial_putc(*s);
 126                s++;
 127        }
 128}
 129
 130static __init void early_serial_hw_init(unsigned divisor)
 131{
 132        unsigned char c;
 133
 134        serial_out(early_serial_base, LCR, 0x3);        /* 8n1 */
 135        serial_out(early_serial_base, IER, 0);  /* no interrupt */
 136        serial_out(early_serial_base, FCR, 0);  /* no fifo */
 137        serial_out(early_serial_base, MCR, 0x3);        /* DTR + RTS */
 138
 139        c = serial_in(early_serial_base, LCR);
 140        serial_out(early_serial_base, LCR, c | DLAB);
 141        serial_out(early_serial_base, DLL, divisor & 0xff);
 142        serial_out(early_serial_base, DLH, (divisor >> 8) & 0xff);
 143        serial_out(early_serial_base, LCR, c & ~DLAB);
 144}
 145
 146#define DEFAULT_BAUD 9600
 147
 148static __init void early_serial_init(char *s)
 149{
 150        unsigned divisor;
 151        unsigned long baud = DEFAULT_BAUD;
 152        char *e;
 153
 154        if (*s == ',')
 155                ++s;
 156
 157        if (*s) {
 158                unsigned port;
 159                if (!strncmp(s, "0x", 2)) {
 160                        early_serial_base = simple_strtoul(s, &e, 16);
 161                } else {
 162                        static const int __initconst bases[] = { 0x3f8, 0x2f8 };
 163
 164                        if (!strncmp(s, "ttyS", 4))
 165                                s += 4;
 166                        port = simple_strtoul(s, &e, 10);
 167                        if (port > 1 || s == e)
 168                                port = 0;
 169                        early_serial_base = bases[port];
 170                }
 171                s += strcspn(s, ",");
 172                if (*s == ',')
 173                        s++;
 174        }
 175
 176        if (*s) {
 177                baud = simple_strtoull(s, &e, 0);
 178
 179                if (baud == 0 || s == e)
 180                        baud = DEFAULT_BAUD;
 181        }
 182
 183        /* Convert from baud to divisor value */
 184        divisor = 115200 / baud;
 185
 186        /* These will always be IO based ports */
 187        serial_in = io_serial_in;
 188        serial_out = io_serial_out;
 189
 190        /* Set up the HW */
 191        early_serial_hw_init(divisor);
 192}
 193
 194#ifdef CONFIG_PCI
 195static void mem32_serial_out(unsigned long addr, int offset, int value)
 196{
 197        u32 __iomem *vaddr = (u32 __iomem *)addr;
 198        /* shift implied by pointer type */
 199        writel(value, vaddr + offset);
 200}
 201
 202static unsigned int mem32_serial_in(unsigned long addr, int offset)
 203{
 204        u32 __iomem *vaddr = (u32 __iomem *)addr;
 205        /* shift implied by pointer type */
 206        return readl(vaddr + offset);
 207}
 208
 209/*
 210 * early_pci_serial_init()
 211 *
 212 * This function is invoked when the early_printk param starts with "pciserial"
 213 * The rest of the param should be "[force],B:D.F,baud", where B, D & F describe
 214 * the location of a PCI device that must be a UART device. "force" is optional
 215 * and overrides the use of an UART device with a wrong PCI class code.
 216 */
 217static __init void early_pci_serial_init(char *s)
 218{
 219        unsigned divisor;
 220        unsigned long baud = DEFAULT_BAUD;
 221        u8 bus, slot, func;
 222        u32 classcode, bar0;
 223        u16 cmdreg;
 224        char *e;
 225        int force = 0;
 226
 227        if (*s == ',')
 228                ++s;
 229
 230        if (*s == 0)
 231                return;
 232
 233        /* Force the use of an UART device with wrong class code */
 234        if (!strncmp(s, "force,", 6)) {
 235                force = 1;
 236                s += 6;
 237        }
 238
 239        /*
 240         * Part the param to get the BDF values
 241         */
 242        bus = (u8)simple_strtoul(s, &e, 16);
 243        s = e;
 244        if (*s != ':')
 245                return;
 246        ++s;
 247        slot = (u8)simple_strtoul(s, &e, 16);
 248        s = e;
 249        if (*s != '.')
 250                return;
 251        ++s;
 252        func = (u8)simple_strtoul(s, &e, 16);
 253        s = e;
 254
 255        /* A baud might be following */
 256        if (*s == ',')
 257                s++;
 258
 259        /*
 260         * Find the device from the BDF
 261         */
 262        cmdreg = read_pci_config(bus, slot, func, PCI_COMMAND);
 263        classcode = read_pci_config(bus, slot, func, PCI_CLASS_REVISION);
 264        bar0 = read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_0);
 265
 266        /*
 267         * Verify it is a UART type device
 268         */
 269        if (((classcode >> 16 != PCI_CLASS_COMMUNICATION_MODEM) &&
 270             (classcode >> 16 != PCI_CLASS_COMMUNICATION_SERIAL)) ||
 271           (((classcode >> 8) & 0xff) != 0x02)) /* 16550 I/F at BAR0 */ {
 272                if (!force)
 273                        return;
 274        }
 275
 276        /*
 277         * Determine if it is IO or memory mapped
 278         */
 279        if (bar0 & 0x01) {
 280                /* it is IO mapped */
 281                serial_in = io_serial_in;
 282                serial_out = io_serial_out;
 283                early_serial_base = bar0&0xfffffffc;
 284                write_pci_config(bus, slot, func, PCI_COMMAND,
 285                                                cmdreg|PCI_COMMAND_IO);
 286        } else {
 287                /* It is memory mapped - assume 32-bit alignment */
 288                serial_in = mem32_serial_in;
 289                serial_out = mem32_serial_out;
 290                /* WARNING! assuming the address is always in the first 4G */
 291                early_serial_base =
 292                        (unsigned long)early_ioremap(bar0 & 0xfffffff0, 0x10);
 293                write_pci_config(bus, slot, func, PCI_COMMAND,
 294                                                cmdreg|PCI_COMMAND_MEMORY);
 295        }
 296
 297        /*
 298         * Initialize the hardware
 299         */
 300        if (*s) {
 301                if (strcmp(s, "nocfg") == 0)
 302                        /* Sometimes, we want to leave the UART alone
 303                         * and assume the BIOS has set it up correctly.
 304                         * "nocfg" tells us this is the case, and we
 305                         * should do no more setup.
 306                         */
 307                        return;
 308                if (kstrtoul(s, 0, &baud) < 0 || baud == 0)
 309                        baud = DEFAULT_BAUD;
 310        }
 311
 312        /* Convert from baud to divisor value */
 313        divisor = 115200 / baud;
 314
 315        /* Set up the HW */
 316        early_serial_hw_init(divisor);
 317}
 318#endif
 319
 320static struct console early_serial_console = {
 321        .name =         "earlyser",
 322        .write =        early_serial_write,
 323        .flags =        CON_PRINTBUFFER,
 324        .index =        -1,
 325};
 326
 327static void early_console_register(struct console *con, int keep_early)
 328{
 329        if (con->index != -1) {
 330                printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
 331                       con->name);
 332                return;
 333        }
 334        early_console = con;
 335        if (keep_early)
 336                early_console->flags &= ~CON_BOOT;
 337        else
 338                early_console->flags |= CON_BOOT;
 339        register_console(early_console);
 340}
 341
 342static int __init setup_early_printk(char *buf)
 343{
 344        int keep;
 345
 346        if (!buf)
 347                return 0;
 348
 349        if (early_console)
 350                return 0;
 351
 352        keep = (strstr(buf, "keep") != NULL);
 353
 354        while (*buf != '\0') {
 355                if (!strncmp(buf, "serial", 6)) {
 356                        buf += 6;
 357                        early_serial_init(buf);
 358                        early_console_register(&early_serial_console, keep);
 359                        if (!strncmp(buf, ",ttyS", 5))
 360                                buf += 5;
 361                }
 362                if (!strncmp(buf, "ttyS", 4)) {
 363                        early_serial_init(buf + 4);
 364                        early_console_register(&early_serial_console, keep);
 365                }
 366#ifdef CONFIG_PCI
 367                if (!strncmp(buf, "pciserial", 9)) {
 368                        early_pci_serial_init(buf + 9);
 369                        early_console_register(&early_serial_console, keep);
 370                        buf += 9; /* Keep from match the above "serial" */
 371                }
 372#endif
 373                if (!strncmp(buf, "vga", 3) &&
 374                    boot_params.screen_info.orig_video_isVGA == 1) {
 375                        max_xpos = boot_params.screen_info.orig_video_cols;
 376                        max_ypos = boot_params.screen_info.orig_video_lines;
 377                        current_ypos = boot_params.screen_info.orig_y;
 378                        early_console_register(&early_vga_console, keep);
 379                }
 380#ifdef CONFIG_EARLY_PRINTK_DBGP
 381                if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
 382                        early_console_register(&early_dbgp_console, keep);
 383#endif
 384#ifdef CONFIG_HVC_XEN
 385                if (!strncmp(buf, "xen", 3))
 386                        early_console_register(&xenboot_console, keep);
 387#endif
 388#ifdef CONFIG_EARLY_PRINTK_USB_XDBC
 389                if (!strncmp(buf, "xdbc", 4))
 390                        early_xdbc_parse_parameter(buf + 4);
 391#endif
 392
 393                buf++;
 394        }
 395        return 0;
 396}
 397
 398early_param("earlyprintk", setup_early_printk);
 399