1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2014 Linaro Ltd. 4 * Author: Rob Herring <robh@kernel.org> 5 * 6 * Based on 8250 earlycon: 7 * (c) Copyright 2004 Hewlett-Packard Development Company, L.P. 8 * Bjorn Helgaas <bjorn.helgaas@hp.com> 9 */ 10 11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 12 13 #include <linux/console.h> 14 #include <linux/kernel.h> 15 #include <linux/init.h> 16 #include <linux/io.h> 17 #include <linux/serial_core.h> 18 #include <linux/sizes.h> 19 #include <linux/of.h> 20 #include <linux/of_fdt.h> 21 #include <linux/acpi.h> 22 23 #ifdef CONFIG_FIX_EARLYCON_MEM 24 #include <asm/fixmap.h> 25 #endif 26 27 #include <asm/serial.h> 28 29 static struct console early_con = { 30 .name = "uart", /* fixed up at earlycon registration */ 31 .flags = CON_PRINTBUFFER | CON_BOOT, 32 .index = 0, 33 }; 34 35 static struct earlycon_device early_console_dev = { 36 .con = &early_con, 37 }; 38 39 static void __iomem * __init earlycon_map(resource_size_t paddr, size_t size) 40 { 41 void __iomem *base; 42 #ifdef CONFIG_FIX_EARLYCON_MEM 43 set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr & PAGE_MASK); 44 base = (void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE); 45 base += paddr & ~PAGE_MASK; 46 #else 47 base = ioremap(paddr, size); 48 #endif 49 if (!base) 50 pr_err("%s: Couldn't map %pa\n", __func__, &paddr); 51 52 return base; 53 } 54 55 static void __init earlycon_init(struct earlycon_device *device, 56 const char *name) 57 { 58 struct console *earlycon = device->con; 59 const char *s; 60 size_t len; 61 62 /* scan backwards from end of string for first non-numeral */ 63 for (s = name + strlen(name); 64 s > name && s[-1] >= '0' && s[-1] <= '9'; 65 s--) 66 ; 67 if (*s) 68 earlycon->index = simple_strtoul(s, NULL, 10); 69 len = s - name; 70 strlcpy(earlycon->name, name, min(len + 1, sizeof(earlycon->name))); 71 earlycon->data = &early_console_dev; 72 } 73 74 static void __init earlycon_print_info(struct earlycon_device *device) 75 { 76 struct console *earlycon = device->con; 77 struct uart_port *port = &device->port; 78 79 if (port->iotype == UPIO_MEM || port->iotype == UPIO_MEM16 || 80 port->iotype == UPIO_MEM32 || port->iotype == UPIO_MEM32BE) 81 pr_info("%s%d at MMIO%s %pa (options '%s')\n", 82 earlycon->name, earlycon->index, 83 (port->iotype == UPIO_MEM) ? "" : 84 (port->iotype == UPIO_MEM16) ? "16" : 85 (port->iotype == UPIO_MEM32) ? "32" : "32be", 86 &port->mapbase, device->options); 87 else 88 pr_info("%s%d at I/O port 0x%lx (options '%s')\n", 89 earlycon->name, earlycon->index, 90 port->iobase, device->options); 91 } 92 93 static int __init parse_options(struct earlycon_device *device, char *options) 94 { 95 struct uart_port *port = &device->port; 96 int length; 97 resource_size_t addr; 98 99 if (uart_parse_earlycon(options, &port->iotype, &addr, &options)) 100 return -EINVAL; 101 102 switch (port->iotype) { 103 case UPIO_MEM: 104 port->mapbase = addr; 105 break; 106 case UPIO_MEM16: 107 port->regshift = 1; 108 port->mapbase = addr; 109 break; 110 case UPIO_MEM32: 111 case UPIO_MEM32BE: 112 port->regshift = 2; 113 port->mapbase = addr; 114 break; 115 case UPIO_PORT: 116 port->iobase = addr; 117 break; 118 default: 119 return -EINVAL; 120 } 121 122 if (options) { 123 device->baud = simple_strtoul(options, NULL, 0); 124 length = min(strcspn(options, " ") + 1, 125 (size_t)(sizeof(device->options))); 126 strlcpy(device->options, options, length); 127 } 128 129 return 0; 130 } 131 132 static int __init register_earlycon(char *buf, const struct earlycon_id *match) 133 { 134 int err; 135 struct uart_port *port = &early_console_dev.port; 136 137 /* On parsing error, pass the options buf to the setup function */ 138 if (buf && !parse_options(&early_console_dev, buf)) 139 buf = NULL; 140 141 spin_lock_init(&port->lock); 142 port->uartclk = BASE_BAUD * 16; 143 if (port->mapbase) 144 port->membase = earlycon_map(port->mapbase, 64); 145 146 earlycon_init(&early_console_dev, match->name); 147 err = match->setup(&early_console_dev, buf); 148 earlycon_print_info(&early_console_dev); 149 if (err < 0) 150 return err; 151 if (!early_console_dev.con->write) 152 return -ENODEV; 153 154 register_console(early_console_dev.con); 155 return 0; 156 } 157 158 /** 159 * setup_earlycon - match and register earlycon console 160 * @buf: earlycon param string 161 * 162 * Registers the earlycon console matching the earlycon specified 163 * in the param string @buf. Acceptable param strings are of the form 164 * <name>,io|mmio|mmio32|mmio32be,<addr>,<options> 165 * <name>,0x<addr>,<options> 166 * <name>,<options> 167 * <name> 168 * 169 * Only for the third form does the earlycon setup() method receive the 170 * <options> string in the 'options' parameter; all other forms set 171 * the parameter to NULL. 172 * 173 * Returns 0 if an attempt to register the earlycon was made, 174 * otherwise negative error code 175 */ 176 int __init setup_earlycon(char *buf) 177 { 178 const struct earlycon_id **p_match; 179 bool empty_compatible = true; 180 181 if (!buf || !buf[0]) 182 return -EINVAL; 183 184 if (early_con.flags & CON_ENABLED) 185 return -EALREADY; 186 187 again: 188 for (p_match = __earlycon_table; p_match < __earlycon_table_end; 189 p_match++) { 190 const struct earlycon_id *match = *p_match; 191 size_t len = strlen(match->name); 192 193 if (strncmp(buf, match->name, len)) 194 continue; 195 196 /* prefer entries with empty compatible */ 197 if (empty_compatible && *match->compatible) 198 continue; 199 200 if (buf[len]) { 201 if (buf[len] != ',') 202 continue; 203 buf += len + 1; 204 } else 205 buf = NULL; 206 207 return register_earlycon(buf, match); 208 } 209 210 if (empty_compatible) { 211 empty_compatible = false; 212 goto again; 213 } 214 215 return -ENOENT; 216 } 217 218 /* 219 * This defers the initialization of the early console until after ACPI has 220 * been initialized. 221 */ 222 bool earlycon_acpi_spcr_enable __initdata; 223 224 /* early_param wrapper for setup_earlycon() */ 225 static int __init param_setup_earlycon(char *buf) 226 { 227 int err; 228 229 /* Just 'earlycon' is a valid param for devicetree and ACPI SPCR. */ 230 if (!buf || !buf[0]) { 231 if (IS_ENABLED(CONFIG_ACPI_SPCR_TABLE)) { 232 earlycon_acpi_spcr_enable = true; 233 return 0; 234 } else if (!buf) { 235 return early_init_dt_scan_chosen_stdout(); 236 } 237 } 238 239 err = setup_earlycon(buf); 240 if (err == -ENOENT || err == -EALREADY) 241 return 0; 242 return err; 243 } 244 early_param("earlycon", param_setup_earlycon); 245 246 #ifdef CONFIG_OF_EARLY_FLATTREE 247 248 int __init of_setup_earlycon(const struct earlycon_id *match, 249 unsigned long node, 250 const char *options) 251 { 252 int err; 253 struct uart_port *port = &early_console_dev.port; 254 const __be32 *val; 255 bool big_endian; 256 u64 addr; 257 258 spin_lock_init(&port->lock); 259 port->iotype = UPIO_MEM; 260 addr = of_flat_dt_translate_address(node); 261 if (addr == OF_BAD_ADDR) { 262 pr_warn("[%s] bad address\n", match->name); 263 return -ENXIO; 264 } 265 port->mapbase = addr; 266 267 val = of_get_flat_dt_prop(node, "reg-offset", NULL); 268 if (val) 269 port->mapbase += be32_to_cpu(*val); 270 port->membase = earlycon_map(port->mapbase, SZ_4K); 271 272 val = of_get_flat_dt_prop(node, "reg-shift", NULL); 273 if (val) 274 port->regshift = be32_to_cpu(*val); 275 big_endian = of_get_flat_dt_prop(node, "big-endian", NULL) != NULL || 276 (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) && 277 of_get_flat_dt_prop(node, "native-endian", NULL) != NULL); 278 val = of_get_flat_dt_prop(node, "reg-io-width", NULL); 279 if (val) { 280 switch (be32_to_cpu(*val)) { 281 case 1: 282 port->iotype = UPIO_MEM; 283 break; 284 case 2: 285 port->iotype = UPIO_MEM16; 286 break; 287 case 4: 288 port->iotype = (big_endian) ? UPIO_MEM32BE : UPIO_MEM32; 289 break; 290 default: 291 pr_warn("[%s] unsupported reg-io-width\n", match->name); 292 return -EINVAL; 293 } 294 } 295 296 val = of_get_flat_dt_prop(node, "current-speed", NULL); 297 if (val) 298 early_console_dev.baud = be32_to_cpu(*val); 299 300 val = of_get_flat_dt_prop(node, "clock-frequency", NULL); 301 if (val) 302 port->uartclk = be32_to_cpu(*val); 303 304 if (options) { 305 early_console_dev.baud = simple_strtoul(options, NULL, 0); 306 strlcpy(early_console_dev.options, options, 307 sizeof(early_console_dev.options)); 308 } 309 earlycon_init(&early_console_dev, match->name); 310 err = match->setup(&early_console_dev, options); 311 earlycon_print_info(&early_console_dev); 312 if (err < 0) 313 return err; 314 if (!early_console_dev.con->write) 315 return -ENODEV; 316 317 318 register_console(early_console_dev.con); 319 return 0; 320 } 321 322 #endif /* CONFIG_OF_EARLY_FLATTREE */ 323