early_printk.c

  1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/console.h>
  3#include <linux/kernel.h>
  4#include <linux/kexec.h>
  5#include <linux/init.h>
  6#include <linux/string.h>
  7#include <linux/screen_info.h>
  8#include <linux/usb/ch9.h>
  9#include <linux/pci_regs.h>
 10#include <linux/pci_ids.h>
 11#include <linux/errno.h>
 12#include <linux/pgtable.h>
 13#include <asm/io.h>
 14#include <asm/processor.h>
 15#include <asm/fcntl.h>
 16#include <asm/setup.h>
 17#include <xen/hvc-console.h>
 18#include <asm/pci-direct.h>
 19#include <asm/fixmap.h>
 20#include <linux/usb/ehci_def.h>
 21#include <linux/usb/xhci-dbgp.h>
 22#include <asm/pci_x86.h>
 23#include <linux/static_call.h>
 24
 25/* Simple VGA output */
 26#define VGABASE		(__ISA_IO_base + 0xb8000)
 27
 28static int max_ypos = 25, max_xpos = 80;
 29static int current_ypos = 25, current_xpos;
 30
 31static void early_vga_write(struct console *con, const char *str, unsigned n)
 32{
 33	char c;
 34	int  i, k, j;
 35
 36	while ((c = *str++) != '\0' && n-- > 0) {
 37		if (current_ypos >= max_ypos) {
 38			/* scroll 1 line up */
 39			for (k = 1, j = 0; k < max_ypos; k++, j++) {
 40				for (i = 0; i < max_xpos; i++) {
 41					writew(readw(VGABASE+2*(max_xpos*k+i)),
 42					       VGABASE + 2*(max_xpos*j + i));
 43				}
 44			}
 45			for (i = 0; i < max_xpos; i++)
 46				writew(0x720, VGABASE + 2*(max_xpos*j + i));
 47			current_ypos = max_ypos-1;
 48		}
 49#ifdef CONFIG_KGDB_KDB
 50		if (c == '\b') {
 51			if (current_xpos > 0)
 52				current_xpos--;
 53		} else if (c == '\r') {
 54			current_xpos = 0;
 55		} else
 56#endif
 57		if (c == '\n') {
 58			current_xpos = 0;
 59			current_ypos++;
 60		} else if (c != '\r')  {
 61			writew(((0x7 << 8) | (unsigned short) c),
 62			       VGABASE + 2*(max_xpos*current_ypos +
 63						current_xpos++));
 64			if (current_xpos >= max_xpos) {
 65				current_xpos = 0;
 66				current_ypos++;
 67			}
 68		}
 69	}
 70}
 71
 72static struct console early_vga_console = {
 73	.name =		"earlyvga",
 74	.write =	early_vga_write,
 75	.flags =	CON_PRINTBUFFER,
 76	.index =	-1,
 77};
 78
 79/* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
 80
 81static unsigned long early_serial_base = 0x3f8;  /* ttyS0 */
 82
 83#define XMTRDY          0x20
 84
 85#define DLAB		0x80
 86
 87#define TXR             0       /*  Transmit register (WRITE) */
 88#define RXR             0       /*  Receive register  (READ)  */
 89#define IER             1       /*  Interrupt Enable          */
 90#define IIR             2       /*  Interrupt ID              */
 91#define FCR             2       /*  FIFO control              */
 92#define LCR             3       /*  Line control              */
 93#define MCR             4       /*  Modem control             */
 94#define LSR             5       /*  Line Status               */
 95#define MSR             6       /*  Modem Status              */
 96#define DLL             0       /*  Divisor Latch Low         */
 97#define DLH             1       /*  Divisor latch High        */
 98
 99static __noendbr unsigned int io_serial_in(unsigned long addr, int offset)
100{
101	return inb(addr + offset);
102}
103ANNOTATE_NOENDBR_SYM(io_serial_in);
104
105static __noendbr void io_serial_out(unsigned long addr, int offset, int value)
106{
107	outb(value, addr + offset);
108}
109ANNOTATE_NOENDBR_SYM(io_serial_out);
110
111DEFINE_STATIC_CALL(serial_in, io_serial_in);
112DEFINE_STATIC_CALL(serial_out, io_serial_out);
113
114static int early_serial_putc(unsigned char ch)
115{
116	unsigned timeout = 0xffff;
117
118	while ((static_call(serial_in)(early_serial_base, LSR) & XMTRDY) == 0 && --timeout)
119		cpu_relax();
120	static_call(serial_out)(early_serial_base, TXR, ch);
121	return timeout ? 0 : -1;
122}
123
124static void early_serial_write(struct console *con, const char *s, unsigned n)
125{
126	while (*s && n-- > 0) {
127		if (*s == '\n')
128			early_serial_putc('\r');
129		early_serial_putc(*s);
130		s++;
131	}
132}
133
134static __init void early_serial_hw_init(unsigned divisor)
135{
136	unsigned char c;
137
138	static_call(serial_out)(early_serial_base, LCR, 0x3);	/* 8n1 */
139	static_call(serial_out)(early_serial_base, IER, 0);	/* no interrupt */
140	static_call(serial_out)(early_serial_base, FCR, 0);	/* no fifo */
141	static_call(serial_out)(early_serial_base, MCR, 0x3);	/* DTR + RTS */
142
143	c = static_call(serial_in)(early_serial_base, LCR);
144	static_call(serial_out)(early_serial_base, LCR, c | DLAB);
145	static_call(serial_out)(early_serial_base, DLL, divisor & 0xff);
146	static_call(serial_out)(early_serial_base, DLH, (divisor >> 8) & 0xff);
147	static_call(serial_out)(early_serial_base, LCR, c & ~DLAB);
148
149#if defined(CONFIG_KEXEC_CORE) && defined(CONFIG_X86_64)
150	if (static_call_query(serial_in) == io_serial_in)
151		kexec_debug_8250_port = early_serial_base;
152#endif
153}
154
155#define DEFAULT_BAUD 9600
156
157static __init void early_serial_init(char *s)
158{
159	unsigned divisor;
160	unsigned long baud = DEFAULT_BAUD;
161	char *e;
162
163	if (*s == ',')
164		++s;
165
166	if (*s) {
167		unsigned port;
168		if (!strncmp(s, "0x", 2)) {
169			early_serial_base = simple_strtoul(s, &e, 16);
170		} else {
171			static const int __initconst bases[] = { 0x3f8, 0x2f8 };
172
173			if (!strncmp(s, "ttyS", 4))
174				s += 4;
175			port = simple_strtoul(s, &e, 10);
176			if (port > 1 || s == e)
177				port = 0;
178			early_serial_base = bases[port];
179		}
180		s += strcspn(s, ",");
181		if (*s == ',')
182			s++;
183	}
184
185	if (*s) {
186		baud = simple_strtoull(s, &e, 0);
187
188		if (baud == 0 || s == e)
189			baud = DEFAULT_BAUD;
190	}
191
192	/* Convert from baud to divisor value */
193	divisor = 115200 / baud;
194
195	/* Set up the HW */
196	early_serial_hw_init(divisor);
197}
198
199static __noendbr void mem32_serial_out(unsigned long addr, int offset, int value)
200{
201	u32 __iomem *vaddr = (u32 __iomem *)addr;
202	/* shift implied by pointer type */
203	writel(value, vaddr + offset);
204}
205ANNOTATE_NOENDBR_SYM(mem32_serial_out);
206
207static __noendbr unsigned int mem32_serial_in(unsigned long addr, int offset)
208{
209	u32 __iomem *vaddr = (u32 __iomem *)addr;
210	/* shift implied by pointer type */
211	return readl(vaddr + offset);
212}
213ANNOTATE_NOENDBR_SYM(mem32_serial_in);
214
215/*
216 * early_mmio_serial_init() - Initialize MMIO-based early serial console.
217 * @s: MMIO-based serial specification.
218 */
219static __init void early_mmio_serial_init(char *s)
220{
221	unsigned long baudrate;
222	unsigned long membase;
223	char *e;
224
225	if (*s == ',')
226		s++;
227
228	if (!strncmp(s, "0x", 2)) {
229		/* NB: only 32-bit addresses are supported. */
230		membase = simple_strtoul(s, &e, 16);
231		early_serial_base = (unsigned long)early_ioremap(membase, PAGE_SIZE);
232
233		static_call_update(serial_in, mem32_serial_in);
234		static_call_update(serial_out, mem32_serial_out);
235
236		s += strcspn(s, ",");
237		if (*s == ',')
238			s++;
239	}
240
241	if (!strncmp(s, "nocfg", 5)) {
242		baudrate = 0;
243	} else {
244		baudrate = simple_strtoul(s, &e, 0);
245		if (baudrate == 0 || s == e)
246			baudrate = DEFAULT_BAUD;
247	}
248
249	if (baudrate)
250		early_serial_hw_init(115200 / baudrate);
251}
252
253#ifdef CONFIG_PCI
254/*
255 * early_pci_serial_init()
256 *
257 * This function is invoked when the early_printk param starts with "pciserial"
258 * The rest of the param should be "[force],B:D.F,baud", where B, D & F describe
259 * the location of a PCI device that must be a UART device. "force" is optional
260 * and overrides the use of an UART device with a wrong PCI class code.
261 */
262static __init void early_pci_serial_init(char *s)
263{
264	unsigned divisor;
265	unsigned long baud = DEFAULT_BAUD;
266	u8 bus, slot, func;
267	u32 classcode, bar0;
268	u16 cmdreg;
269	char *e;
270	int force = 0;
271
272	if (*s == ',')
273		++s;
274
275	if (*s == 0)
276		return;
277
278	/* Force the use of an UART device with wrong class code */
279	if (!strncmp(s, "force,", 6)) {
280		force = 1;
281		s += 6;
282	}
283
284	/*
285	 * Part the param to get the BDF values
286	 */
287	bus = (u8)simple_strtoul(s, &e, 16);
288	s = e;
289	if (*s != ':')
290		return;
291	++s;
292	slot = (u8)simple_strtoul(s, &e, 16);
293	s = e;
294	if (*s != '.')
295		return;
296	++s;
297	func = (u8)simple_strtoul(s, &e, 16);
298	s = e;
299
300	/* A baud might be following */
301	if (*s == ',')
302		s++;
303
304	/*
305	 * Find the device from the BDF
306	 */
307	cmdreg = read_pci_config(bus, slot, func, PCI_COMMAND);
308	classcode = read_pci_config(bus, slot, func, PCI_CLASS_REVISION);
309	bar0 = read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_0);
310
311	/*
312	 * Verify it is a 16550-UART type device
313	 */
314	if (((classcode >> 16 != PCI_CLASS_COMMUNICATION_MODEM) &&
315	     (classcode >> 16 != PCI_CLASS_COMMUNICATION_SERIAL)) ||
316	    (((classcode >> 8) & 0xff) != PCI_SERIAL_16550_COMPATIBLE)) {
317		if (!force)
318			return;
319	}
320
321	/*
322	 * Determine if it is IO or memory mapped
323	 */
324	if ((bar0 & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {
325		/* it is IO mapped */
326		early_serial_base = bar0 & PCI_BASE_ADDRESS_IO_MASK;
327		write_pci_config(bus, slot, func, PCI_COMMAND,
328				 cmdreg|PCI_COMMAND_IO);
329	} else {
330		/* It is memory mapped - assume 32-bit alignment */
331		static_call_update(serial_in, mem32_serial_in);
332		static_call_update(serial_out, mem32_serial_out);
333		/* WARNING! assuming the address is always in the first 4G */
334		early_serial_base =
335			(unsigned long)early_ioremap(bar0 & PCI_BASE_ADDRESS_MEM_MASK, 0x10);
336#if defined(CONFIG_KEXEC_CORE) && defined(CONFIG_X86_64)
337		kexec_debug_8250_mmio32 = bar0 & PCI_BASE_ADDRESS_MEM_MASK;
338#endif
339		write_pci_config(bus, slot, func, PCI_COMMAND,
340				 cmdreg|PCI_COMMAND_MEMORY);
341	}
342
343	/*
344	 * Initialize the hardware
345	 */
346	if (*s) {
347		if (strcmp(s, "nocfg") == 0)
348			/* Sometimes, we want to leave the UART alone
349			 * and assume the BIOS has set it up correctly.
350			 * "nocfg" tells us this is the case, and we
351			 * should do no more setup.
352			 */
353			return;
354		if (kstrtoul(s, 0, &baud) < 0 || baud == 0)
355			baud = DEFAULT_BAUD;
356	}
357
358	/* Convert from baud to divisor value */
359	divisor = 115200 / baud;
360
361	/* Set up the HW */
362	early_serial_hw_init(divisor);
363}
364#endif
365
366static struct console early_serial_console = {
367	.name =		"earlyser",
368	.write =	early_serial_write,
369	.flags =	CON_PRINTBUFFER,
370	.index =	-1,
371};
372
373static void early_console_register(struct console *con, int keep_early)
374{
375	if (con->index != -1) {
376		printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
377		       con->name);
378		return;
379	}
380	early_console = con;
381	if (keep_early)
382		early_console->flags &= ~CON_BOOT;
383	else
384		early_console->flags |= CON_BOOT;
385	register_console(early_console);
386}
387
388static int __init setup_early_printk(char *buf)
389{
390	int keep;
391
392	if (!buf)
393		return 0;
394
395	if (early_console)
396		return 0;
397
398	keep = (strstr(buf, "keep") != NULL);
399
400	while (*buf != '\0') {
401		if (!strncmp(buf, "mmio32", 6)) {
402			buf += 6;
403			early_mmio_serial_init(buf);
404			early_console_register(&early_serial_console, keep);
405		}
406		if (!strncmp(buf, "serial", 6)) {
407			buf += 6;
408			early_serial_init(buf);
409			early_console_register(&early_serial_console, keep);
410			if (!strncmp(buf, ",ttyS", 5))
411				buf += 5;
412		}
413		if (!strncmp(buf, "ttyS", 4)) {
414			early_serial_init(buf + 4);
415			early_console_register(&early_serial_console, keep);
416		}
417#ifdef CONFIG_PCI
418		if (!strncmp(buf, "pciserial", 9)) {
419			buf += 9; /* Keep from match the above "pciserial" */
420			early_pci_serial_init(buf);
421			early_console_register(&early_serial_console, keep);
422		}
423#endif
424		if (!strncmp(buf, "vga", 3) &&
425		    boot_params.screen_info.orig_video_isVGA == 1) {
426			max_xpos = boot_params.screen_info.orig_video_cols;
427			max_ypos = boot_params.screen_info.orig_video_lines;
428			current_ypos = boot_params.screen_info.orig_y;
429			early_console_register(&early_vga_console, keep);
430		}
431#ifdef CONFIG_EARLY_PRINTK_DBGP
432		if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
433			early_console_register(&early_dbgp_console, keep);
434#endif
435#ifdef CONFIG_HVC_XEN
436		if (!strncmp(buf, "xen", 3))
437			early_console_register(&xenboot_console, keep);
438#endif
439#ifdef CONFIG_EARLY_PRINTK_USB_XDBC
440		if (!strncmp(buf, "xdbc", 4))
441			early_xdbc_parse_parameter(buf + 4, keep);
442#endif
443
444		buf++;
445	}
446	return 0;
447}
448
449early_param("earlyprintk", setup_early_printk);