1/*
2 * allow a console to be used for early printk
3 * derived from arch/x86/kernel/early_printk.c
4 *
5 * Copyright 2007-2009 Analog Devices Inc.
6 *
7 * Licensed under the GPL-2
8 */
9
10#include <linux/kernel.h>
11#include <linux/init.h>
12#include <linux/serial_core.h>
13#include <linux/console.h>
14#include <linux/string.h>
15#include <linux/reboot.h>
16#include <asm/blackfin.h>
17#include <asm/irq_handler.h>
18#include <asm/early_printk.h>
19
20#ifdef CONFIG_SERIAL_BFIN
21extern struct console *bfin_earlyserial_init(unsigned int port,
22						unsigned int cflag);
23#endif
24#ifdef CONFIG_BFIN_JTAG_COMM
25extern struct console *bfin_jc_early_init(void);
26#endif
27
28static struct console *early_console;
29
30/* Default console */
31#define DEFAULT_PORT 0
32#define DEFAULT_CFLAG CS8|B57600
33
34/* Default console for early crashes */
35#define DEFAULT_EARLY_PORT "serial,uart0,57600"
36
37#ifdef CONFIG_SERIAL_CORE
38/* What should get here is "0,57600" */
39static struct console * __init earlyserial_init(char *buf)
40{
41	int baud, bit;
42	char parity;
43	unsigned int serial_port = DEFAULT_PORT;
44	unsigned int cflag = DEFAULT_CFLAG;
45
46	serial_port = simple_strtoul(buf, &buf, 10);
47	buf++;
48
49	cflag = 0;
50	baud = simple_strtoul(buf, &buf, 10);
51	switch (baud) {
52	case 1200:
53		cflag |= B1200;
54		break;
55	case 2400:
56		cflag |= B2400;
57		break;
58	case 4800:
59		cflag |= B4800;
60		break;
61	case 9600:
62		cflag |= B9600;
63		break;
64	case 19200:
65		cflag |= B19200;
66		break;
67	case 38400:
68		cflag |= B38400;
69		break;
70	case 115200:
71		cflag |= B115200;
72		break;
73	default:
74		cflag |= B57600;
75	}
76
77	parity = buf[0];
78	buf++;
79	switch (parity) {
80	case 'e':
81		cflag |= PARENB;
82		break;
83	case 'o':
84		cflag |= PARODD;
85		break;
86	}
87
88	bit = simple_strtoul(buf, &buf, 10);
89	switch (bit) {
90	case 5:
91		cflag |= CS5;
92		break;
93	case 6:
94		cflag |= CS6;
95		break;
96	case 7:
97		cflag |= CS7;
98		break;
99	default:
100		cflag |= CS8;
101	}
102
103#ifdef CONFIG_SERIAL_BFIN
104	return bfin_earlyserial_init(serial_port, cflag);
105#else
106	return NULL;
107#endif
108
109}
110#endif
111
112int __init setup_early_printk(char *buf)
113{
114
115	/* Crashing in here would be really bad, so check both the var
116	   and the pointer before we start using it
117	 */
118	if (!buf)
119		return 0;
120
121	if (!*buf)
122		return 0;
123
124	if (early_console != NULL)
125		return 0;
126
127#ifdef CONFIG_SERIAL_BFIN
128	/* Check for Blackfin Serial */
129	if (!strncmp(buf, "serial,uart", 11)) {
130		buf += 11;
131		early_console = earlyserial_init(buf);
132	}
133#endif
134
135#ifdef CONFIG_BFIN_JTAG_COMM
136	/* Check for Blackfin JTAG */
137	if (!strncmp(buf, "jtag", 4)) {
138		buf += 4;
139		early_console = bfin_jc_early_init();
140	}
141#endif
142
143#ifdef CONFIG_FB
144		/* TODO: add framebuffer console support */
145#endif
146
147	if (likely(early_console)) {
148		early_console->flags |= CON_BOOT;
149
150		register_console(early_console);
151		printk(KERN_INFO "early printk enabled on %s%d\n",
152			early_console->name,
153			early_console->index);
154	}
155
156	return 0;
157}
158
159/*
160 * Set up a temporary Event Vector Table, so if something bad happens before
161 * the kernel is fully started, it doesn't vector off into somewhere we don't
162 * know
163 */
164
165asmlinkage void __init init_early_exception_vectors(void)
166{
167	u32 evt;
168	SSYNC();
169
170	/*
171	 * This starts up the shadow buffer, incase anything crashes before
172	 * setup arch
173	 */
174	mark_shadow_error();
175	early_shadow_puts(linux_banner);
176	early_shadow_stamp();
177
178	if (CPUID != bfin_cpuid()) {
179		early_shadow_puts("Running on wrong machine type, expected");
180		early_shadow_reg(CPUID, 16);
181		early_shadow_puts(", but running on");
182		early_shadow_reg(bfin_cpuid(), 16);
183		early_shadow_puts("\n");
184	}
185
186	/* cannot program in software:
187	 * evt0 - emulation (jtag)
188	 * evt1 - reset
189	 */
190	for (evt = EVT2; evt <= EVT15; evt += 4)
191		bfin_write32(evt, early_trap);
192	CSYNC();
193
194	/* Set all the return from interrupt, exception, NMI to a known place
195	 * so if we do a RETI, RETX or RETN by mistake - we go somewhere known
196	 * Note - don't change RETS - we are in a subroutine, or
197	 * RETE - since it might screw up if emulator is attached
198	 */
199	asm("\tRETI = %0; RETX = %0; RETN = %0;\n"
200		: : "p"(early_trap));
201
202}
203
204__attribute__((__noreturn__))
205asmlinkage void __init early_trap_c(struct pt_regs *fp, void *retaddr)
206{
207	/* This can happen before the uart is initialized, so initialize
208	 * the UART now (but only if we are running on the processor we think
209	 * we are compiled for - otherwise we write to MMRs that don't exist,
210	 * and cause other problems. Nothing comes out the UART, but it does
211	 * end up in the __buf_log.
212	 */
213	if (likely(early_console == NULL) && CPUID == bfin_cpuid())
214		setup_early_printk(DEFAULT_EARLY_PORT);
215
216	if (!shadow_console_enabled()) {
217		/* crap - we crashed before setup_arch() */
218		early_shadow_puts("panic before setup_arch\n");
219		early_shadow_puts("IPEND:");
220		early_shadow_reg(fp->ipend, 16);
221		if (fp->seqstat & SEQSTAT_EXCAUSE) {
222			early_shadow_puts("\nEXCAUSE:");
223			early_shadow_reg(fp->seqstat & SEQSTAT_EXCAUSE, 8);
224		}
225		if (fp->seqstat & SEQSTAT_HWERRCAUSE) {
226			early_shadow_puts("\nHWERRCAUSE:");
227			early_shadow_reg(
228				(fp->seqstat & SEQSTAT_HWERRCAUSE) >> 14, 8);
229		}
230		early_shadow_puts("\nErr @");
231		if (fp->ipend & EVT_EVX)
232			early_shadow_reg(fp->retx, 32);
233		else
234			early_shadow_reg(fp->pc, 32);
235#ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
236		early_shadow_puts("\nTrace:");
237		if (likely(bfin_read_TBUFSTAT() & TBUFCNT)) {
238			while (bfin_read_TBUFSTAT() & TBUFCNT) {
239				early_shadow_puts("\nT  :");
240				early_shadow_reg(bfin_read_TBUF(), 32);
241				early_shadow_puts("\n S :");
242				early_shadow_reg(bfin_read_TBUF(), 32);
243			}
244		}
245#endif
246		early_shadow_puts("\nUse bfin-elf-addr2line to determine "
247			"function names\n");
248		/*
249		 * We should panic(), but we can't - since panic calls printk,
250		 * and printk uses memcpy.
251		 * we want to reboot, but if the machine type is different,
252		 * can't due to machine specific reboot sequences
253		 */
254		if (CPUID == bfin_cpuid()) {
255			early_shadow_puts("Trying to restart\n");
256			machine_restart("");
257		}
258
259		early_shadow_puts("Halting, since it is not safe to restart\n");
260		while (1)
261			asm volatile ("EMUEXCPT; IDLE;\n");
262
263	} else {
264		printk(KERN_EMERG "Early panic\n");
265		show_regs(fp);
266		dump_bfin_trace_buffer();
267	}
268
269	panic("Died early");
270}
271
272early_param("earlyprintk", setup_early_printk);
273