/*
* allow a console to be used for early printk
* derived from arch/x86/kernel/early_printk.c
*
* Copyright 2007-2009 Analog Devices Inc.
*
* Licensed under the GPL-2
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/serial_core.h>
#include <linux/console.h>
#include <linux/string.h>
#include <linux/reboot.h>
#include <asm/blackfin.h>
#include <asm/irq_handler.h>
#include <asm/early_printk.h>
#ifdef CONFIG_SERIAL_BFIN
extern struct console *bfin_earlyserial_init(unsigned int port,
unsigned int cflag);
#endif
#ifdef CONFIG_BFIN_JTAG_COMM
extern struct console *bfin_jc_early_init(void);
#endif
static struct console *early_console;
/* Default console */
#define DEFAULT_PORT 0
#define DEFAULT_CFLAG CS8|B57600
/* Default console for early crashes */
#define DEFAULT_EARLY_PORT "serial,uart0,57600"
#ifdef CONFIG_SERIAL_CORE
/* What should get here is "0,57600" */
static struct console * __init earlyserial_init(char *buf)
{
int baud, bit;
char parity;
unsigned int serial_port = DEFAULT_PORT;
unsigned int cflag = DEFAULT_CFLAG;
serial_port = simple_strtoul(buf, &buf, 10);
buf++;
cflag = 0;
baud = simple_strtoul(buf, &buf, 10);
switch (baud) {
case 1200:
cflag |= B1200;
break;
case 2400:
cflag |= B2400;
break;
case 4800:
cflag |= B4800;
break;
case 9600:
cflag |= B9600;
break;
case 19200:
cflag |= B19200;
break;
case 38400:
cflag |= B38400;
break;
case 115200:
cflag |= B115200;
break;
default:
cflag |= B57600;
}
parity = buf[0];
buf++;
switch (parity) {
case 'e':
cflag |= PARENB;
break;
case 'o':
cflag |= PARODD;
break;
}
bit = simple_strtoul(buf, &buf, 10);
switch (bit) {
case 5:
cflag |= CS5;
break;
case 6:
cflag |= CS6;
break;
case 7:
cflag |= CS7;
break;
default:
cflag |= CS8;
}
#ifdef CONFIG_SERIAL_BFIN
return bfin_earlyserial_init(serial_port, cflag);
#else
return NULL;
#endif
}
#endif
int __init setup_early_printk(char *buf)
{
/* Crashing in here would be really bad, so check both the var
and the pointer before we start using it
*/
if (!buf)
return 0;
if (!*buf)
return 0;
if (early_console != NULL)
return 0;
#ifdef CONFIG_SERIAL_BFIN
/* Check for Blackfin Serial */
if (!strncmp(buf, "serial,uart", 11)) {
buf += 11;
early_console = earlyserial_init(buf);
}
#endif
#ifdef CONFIG_BFIN_JTAG_COMM
/* Check for Blackfin JTAG */
if (!strncmp(buf, "jtag", 4)) {
buf += 4;
early_console = bfin_jc_early_init();
}
#endif
#ifdef CONFIG_FB
/* TODO: add framebuffer console support */
#endif
if (likely(early_console)) {
early_console->flags |= CON_BOOT;
register_console(early_console);
printk(KERN_INFO "early printk enabled on %s%d\n",
early_console->name,
early_console->index);
}
return 0;
}
/*
* Set up a temporary Event Vector Table, so if something bad happens before
* the kernel is fully started, it doesn't vector off into somewhere we don't
* know
*/
asmlinkage void __init init_early_exception_vectors(void)
{
u32 evt;
SSYNC();
/*
* This starts up the shadow buffer, incase anything crashes before
* setup arch
*/
mark_shadow_error();
early_shadow_puts(linux_banner);
early_shadow_stamp();
if (CPUID != bfin_cpuid()) {
early_shadow_puts("Running on wrong machine type, expected");
early_shadow_reg(CPUID, 16);
early_shadow_puts(", but running on");
early_shadow_reg(bfin_cpuid(), 16);
early_shadow_puts("\n");
}
/* cannot program in software:
* evt0 - emulation (jtag)
* evt1 - reset
*/
for (evt = EVT2; evt <= EVT15; evt += 4)
bfin_write32(evt, early_trap);
CSYNC();
/* Set all the return from interrupt, exception, NMI to a known place
* so if we do a RETI, RETX or RETN by mistake - we go somewhere known
* Note - don't change RETS - we are in a subroutine, or
* RETE - since it might screw up if emulator is attached
*/
asm("\tRETI = %0; RETX = %0; RETN = %0;\n"
: : "p"(early_trap));
}
__attribute__((__noreturn__))
asmlinkage void __init early_trap_c(struct pt_regs *fp, void *retaddr)
{
/* This can happen before the uart is initialized, so initialize
* the UART now (but only if we are running on the processor we think
* we are compiled for - otherwise we write to MMRs that don't exist,
* and cause other problems. Nothing comes out the UART, but it does
* end up in the __buf_log.
*/
if (likely(early_console == NULL) && CPUID == bfin_cpuid())
setup_early_printk(DEFAULT_EARLY_PORT);
if (!shadow_console_enabled()) {
/* crap - we crashed before setup_arch() */
early_shadow_puts("panic before setup_arch\n");
early_shadow_puts("IPEND:");
early_shadow_reg(fp->ipend, 16);
if (fp->seqstat & SEQSTAT_EXCAUSE) {
early_shadow_puts("\nEXCAUSE:");
early_shadow_reg(fp->seqstat & SEQSTAT_EXCAUSE, 8);
}
if (fp->seqstat & SEQSTAT_HWERRCAUSE) {
early_shadow_puts("\nHWERRCAUSE:");
early_shadow_reg(
(fp->seqstat & SEQSTAT_HWERRCAUSE) >> 14, 8);
}
early_shadow_puts("\nErr @");
if (fp->ipend & EVT_EVX)
early_shadow_reg(fp->retx, 32);
else
early_shadow_reg(fp->pc, 32);
#ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
early_shadow_puts("\nTrace:");
if (likely(bfin_read_TBUFSTAT() & TBUFCNT)) {
while (bfin_read_TBUFSTAT() & TBUFCNT) {
early_shadow_puts("\nT :");
early_shadow_reg(bfin_read_TBUF(), 32);
early_shadow_puts("\n S :");
early_shadow_reg(bfin_read_TBUF(), 32);
}
}
#endif
early_shadow_puts("\nUse bfin-elf-addr2line to determine "
"function names\n");
/*
* We should panic(), but we can't - since panic calls printk,
* and printk uses memcpy.
* we want to reboot, but if the machine type is different,
* can't due to machine specific reboot sequences
*/
if (CPUID == bfin_cpuid()) {
early_shadow_puts("Trying to restart\n");
machine_restart("");
}
early_shadow_puts("Halting, since it is not safe to restart\n");
while (1)
asm volatile ("EMUEXCPT; IDLE;\n");
} else {
printk(KERN_EMERG "Early panic\n");
show_regs(fp);
dump_bfin_trace_buffer();
}
panic("Died early");
}
early_param("earlyprintk", setup_early_printk);
