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
 29static struct console early_con = {
 30	.name =		"uart",		/* fixed up at earlycon registration */
 31	.flags =	CON_PRINTBUFFER | CON_BOOT,
 32	.index =	0,
 33};
 34
 35static struct earlycon_device early_console_dev = {
 36	.con = &early_con,
 37};
 38
 39static 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
 55static 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	strscpy(earlycon->name, name, min(len + 1, sizeof(earlycon->name)));
 71	earlycon->data = &early_console_dev;
 72}
 73
 74static 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
 93static 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		char *uartclk;
124
125		device->baud = simple_strtoul(options, NULL, 0);
126		uartclk = strchr(options, ',');
127		if (uartclk && kstrtouint(uartclk + 1, 0, &port->uartclk) < 0)
128			pr_warn("[%s] unsupported earlycon uart clkrate option\n",
129				options);
130		length = min(strcspn(options, " ") + 1,
131			     (size_t)(sizeof(device->options)));
132		strscpy(device->options, options, length);
133	}
134
135	return 0;
136}
137
138static int __init register_earlycon(char *buf, const struct earlycon_id *match)
139{
140	int err;
141	struct uart_port *port = &early_console_dev.port;
142
143	/* On parsing error, pass the options buf to the setup function */
144	if (buf && !parse_options(&early_console_dev, buf))
145		buf = NULL;
146
147	spin_lock_init(&port->lock);
148	if (!port->uartclk)
149		port->uartclk = BASE_BAUD * 16;
150	if (port->mapbase)
151		port->membase = earlycon_map(port->mapbase, 64);
152
153	earlycon_init(&early_console_dev, match->name);
154	err = match->setup(&early_console_dev, buf);
155	earlycon_print_info(&early_console_dev);
156	if (err < 0)
157		return err;
158	if (!early_console_dev.con->write)
159		return -ENODEV;
160
161	register_console(early_console_dev.con);
162	return 0;
163}
164
165/**
166 *	setup_earlycon - match and register earlycon console
167 *	@buf:	earlycon param string
168 *
169 *	Registers the earlycon console matching the earlycon specified
170 *	in the param string @buf. Acceptable param strings are of the form
171 *	   <name>,io|mmio|mmio32|mmio32be,<addr>,<options>
172 *	   <name>,0x<addr>,<options>
173 *	   <name>,<options>
174 *	   <name>
175 *
176 *	Only for the third form does the earlycon setup() method receive the
177 *	<options> string in the 'options' parameter; all other forms set
178 *	the parameter to NULL.
179 *
180 *	Returns 0 if an attempt to register the earlycon was made,
181 *	otherwise negative error code
182 */
183int __init setup_earlycon(char *buf)
184{
185	const struct earlycon_id *match;
186	bool empty_compatible = true;
187
188	if (!buf || !buf[0])
189		return -EINVAL;
190
191	if (console_is_registered(&early_con))
192		return -EALREADY;
193
194again:
195	for (match = __earlycon_table; match < __earlycon_table_end; match++) {
196		size_t len = strlen(match->name);
197
198		if (strncmp(buf, match->name, len))
199			continue;
200
201		/* prefer entries with empty compatible */
202		if (empty_compatible && *match->compatible)
203			continue;
204
205		if (buf[len]) {
206			if (buf[len] != ',')
207				continue;
208			buf += len + 1;
209		} else
210			buf = NULL;
211
212		return register_earlycon(buf, match);
213	}
214
215	if (empty_compatible) {
216		empty_compatible = false;
217		goto again;
218	}
219
220	return -ENOENT;
221}
222
223/*
224 * This defers the initialization of the early console until after ACPI has
225 * been initialized.
226 */
227bool earlycon_acpi_spcr_enable __initdata;
228
229/* early_param wrapper for setup_earlycon() */
230static int __init param_setup_earlycon(char *buf)
231{
232	int err;
233
234	/* Just 'earlycon' is a valid param for devicetree and ACPI SPCR. */
235	if (!buf || !buf[0]) {
236		if (IS_ENABLED(CONFIG_ACPI_SPCR_TABLE)) {
237			earlycon_acpi_spcr_enable = true;
238			return 0;
239		} else if (!buf) {
240			return early_init_dt_scan_chosen_stdout();
241		}
242	}
243
244	err = setup_earlycon(buf);
245	if (err == -ENOENT || err == -EALREADY)
246		return 0;
247	return err;
248}
249early_param("earlycon", param_setup_earlycon);
250
251#ifdef CONFIG_OF_EARLY_FLATTREE
252
253int __init of_setup_earlycon(const struct earlycon_id *match,
254			     unsigned long node,
255			     const char *options)
256{
257	int err;
258	struct uart_port *port = &early_console_dev.port;
259	const __be32 *val;
260	bool big_endian;
261	u64 addr;
262
263	if (console_is_registered(&early_con))
264		return -EALREADY;
265
266	spin_lock_init(&port->lock);
267	port->iotype = UPIO_MEM;
268	addr = of_flat_dt_translate_address(node);
269	if (addr == OF_BAD_ADDR) {
270		pr_warn("[%s] bad address\n", match->name);
271		return -ENXIO;
272	}
273	port->mapbase = addr;
274
275	val = of_get_flat_dt_prop(node, "reg-offset", NULL);
276	if (val)
277		port->mapbase += be32_to_cpu(*val);
278	port->membase = earlycon_map(port->mapbase, SZ_4K);
279
280	val = of_get_flat_dt_prop(node, "reg-shift", NULL);
281	if (val)
282		port->regshift = be32_to_cpu(*val);
283	big_endian = of_get_flat_dt_prop(node, "big-endian", NULL) != NULL ||
284		(IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
285		 of_get_flat_dt_prop(node, "native-endian", NULL) != NULL);
286	val = of_get_flat_dt_prop(node, "reg-io-width", NULL);
287	if (val) {
288		switch (be32_to_cpu(*val)) {
289		case 1:
290			port->iotype = UPIO_MEM;
291			break;
292		case 2:
293			port->iotype = UPIO_MEM16;
294			break;
295		case 4:
296			port->iotype = (big_endian) ? UPIO_MEM32BE : UPIO_MEM32;
297			break;
298		default:
299			pr_warn("[%s] unsupported reg-io-width\n", match->name);
300			return -EINVAL;
301		}
302	}
303
304	val = of_get_flat_dt_prop(node, "current-speed", NULL);
305	if (val)
306		early_console_dev.baud = be32_to_cpu(*val);
307
308	val = of_get_flat_dt_prop(node, "clock-frequency", NULL);
309	if (val)
310		port->uartclk = be32_to_cpu(*val);
311
312	if (options) {
313		early_console_dev.baud = simple_strtoul(options, NULL, 0);
314		strscpy(early_console_dev.options, options,
315			sizeof(early_console_dev.options));
316	}
317	earlycon_init(&early_console_dev, match->name);
318	err = match->setup(&early_console_dev, options);
319	earlycon_print_info(&early_console_dev);
320	if (err < 0)
321		return err;
322	if (!early_console_dev.con->write)
323		return -ENODEV;
324
325
326	register_console(early_console_dev.con);
327	return 0;
328}
329
330#endif /* CONFIG_OF_EARLY_FLATTREE */