arch/x86/kernel/early_printk.c

   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
  26 static int max_ypos = 25, max_xpos = 80;
  27 static int current_ypos = 25, current_xpos;
  28
  29 static 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
  70 static 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
  79 static 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
  97 static unsigned int io_serial_in(unsigned long addr, int offset)
  98 {
  99         return inb(addr + offset);
 100 }
 101
 102 static void io_serial_out(unsigned long addr, int offset, int value)
 103 {
 104         outb(value, addr + offset);
 105 }
 106
 107 static unsigned int (*serial_in)(unsigned long addr, int offset) = io_serial_in;
 108 static void (*serial_out)(unsigned long addr, int offset, int value) = io_serial_out;
 109
 110 static 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
 120 static 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
 130 static __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
 148 static __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
 195 static 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
 202 static 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  */
 217 static __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
 320 static struct console early_serial_console = {
 321         .name =         "earlyser",
 322         .write =        early_serial_write,
 323         .flags =        CON_PRINTBUFFER,
 324         .index =        -1,
 325 };
 326
 327 static 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
 342 static 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
 398 early_param("earlyprintk", setup_early_printk);