Blackfin arch: Print out debug info, as early as possible
Robin Getz [Tue, 9 Oct 2007 09:31:46 +0000 (17:31 +0800)]
Print out debug info, as early as possible - even before the
kernel initializes the interrupt vectors. Now we can print out debug
messages almost anytime during the boot process.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

arch/blackfin/kernel/early_printk.c
arch/blackfin/mach-bf533/head.S
arch/blackfin/mach-bf537/head.S
arch/blackfin/mach-bf548/head.S
arch/blackfin/mach-bf561/head.S
arch/blackfin/mach-common/entry.S
include/asm-blackfin/irq_handler.h

index 9bf6170..6ec518a 100644 (file)
@@ -38,13 +38,13 @@ extern struct console *bfin_earlyserial_init(unsigned int port,
 
 static struct console *early_console;
 
-/* Default console
- * Port n == ttyBFn
- * cflags == UART output modes
- */
+/* 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)
@@ -158,4 +158,57 @@ int __init setup_early_printk(char *buf)
        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)
+{
+       SSYNC();
+
+       /* cannot program in software:
+        * evt0 - emulation (jtag)
+        * evt1 - reset
+        */
+       bfin_write_EVT2(early_trap);
+       bfin_write_EVT3(early_trap);
+       bfin_write_EVT5(early_trap);
+       bfin_write_EVT6(early_trap);
+       bfin_write_EVT7(early_trap);
+       bfin_write_EVT8(early_trap);
+       bfin_write_EVT9(early_trap);
+       bfin_write_EVT10(early_trap);
+       bfin_write_EVT11(early_trap);
+       bfin_write_EVT12(early_trap);
+       bfin_write_EVT13(early_trap);
+       bfin_write_EVT14(early_trap);
+       bfin_write_EVT15(early_trap);
+       CSYNC();
+
+       /* Set all the return from interupt, 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));
+
+}
+
+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
+        */
+       if (likely(early_console == NULL))
+               setup_early_printk(DEFAULT_EARLY_PORT);
+
+       dump_bfin_regs(fp, retaddr);
+       dump_bfin_trace_buffer();
+
+       panic("Died early");
+}
+
 early_param("earlyprintk", setup_early_printk);
index fa6dc0d..1ded945 100644 (file)
@@ -181,6 +181,12 @@ ENTRY(__start)
        fp = sp;
        usp = sp;
 
+#ifdef CONFIG_EARLY_PRINTK
+       SP += -12;
+       call _init_early_exception_vectors;
+       SP += 12;
+#endif
+
        /* Put The Code for PLL Programming and SDRAM Programming in L1 ISRAM */
        call _bf53x_relocate_l1_mem;
 #if CONFIG_BFIN_KERNEL_CLOCK
index 2c4ae46..3014fe8 100644 (file)
@@ -224,6 +224,12 @@ ENTRY(__start)
        fp = sp;
        usp = sp;
 
+#ifdef CONFIG_EARLY_PRINTK
+       SP += -12;
+       call _init_early_exception_vectors;
+       SP += 12;
+#endif
+
        /* Put The Code for PLL Programming and SDRAM Programming in L1 ISRAM */
        call _bf53x_relocate_l1_mem;
 #if CONFIG_BFIN_KERNEL_CLOCK
index 532ed09..3071c24 100644 (file)
@@ -125,6 +125,12 @@ ENTRY(__stext)
        FP = SP;
        USP = SP;
 
+#ifdef CONFIG_EARLY_PRINTK
+       SP += -12;
+       call _init_early_exception_vectors;
+       SP += 12;
+#endif
+
        /* Put The Code for PLL Programming and SDRAM Programming in L1 ISRAM */
        call _bf53x_relocate_l1_mem;
 #if CONFIG_BFIN_KERNEL_CLOCK
index fd39891..96a3d45 100644 (file)
@@ -169,6 +169,12 @@ ENTRY(__start)
        fp = sp;
        usp = sp;
 
+#ifdef CONFIG_EARLY_PRINTK
+       SP += -12;
+       call _init_early_exception_vectors;
+       SP += 12;
+#endif
+
        /* Put The Code for PLL Programming and SDRAM Programming in L1 ISRAM */
        call _bf53x_relocate_l1_mem;
 #if CONFIG_BFIN_KERNEL_CLOCK
index e223936..a56b231 100644 (file)
@@ -835,12 +835,13 @@ ENTRY(_ex_trace_buff_full)
        P2 = [sp++];
        P3 = [sp++];
        jump _return_from_exception;
+ENDPROC(_ex_trace_buff_full)
 
 #if CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN == 4
 .data
 #else
 .section .l1.data.B
-#endif
+#endif /* CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN */
 ENTRY(_trace_buff_offset)
         .long 0;
 ALIGN
@@ -848,7 +849,45 @@ ENTRY(_software_trace_buff)
        .rept ((1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN)*256);
        .long 0
        .endr
-#endif
+#endif /* CONFIG_DEBUG_BFIN_HWTRACE_EXPAND */
+
+#if CONFIG_EARLY_PRINTK
+.section .init.text
+ENTRY(_early_trap)
+       SAVE_ALL_SYS
+       trace_buffer_stop(p0,r0);
+
+       /* Turn caches off, to ensure we don't get double exceptions */
+
+       P4.L = LO(IMEM_CONTROL);
+       P4.H = HI(IMEM_CONTROL);
+
+       R5 = [P4];              /* Control Register*/
+       BITCLR(R5,ENICPLB_P);
+       CLI R1;
+       SSYNC;          /* SSYNC required before writing to IMEM_CONTROL. */
+       .align 8;
+       [P4] = R5;
+       SSYNC;
+
+       P4.L = LO(DMEM_CONTROL);
+       P4.H = HI(DMEM_CONTROL);
+       R5 = [P4];
+       BITCLR(R5,ENDCPLB_P);
+       SSYNC;          /* SSYNC required before writing to DMEM_CONTROL. */
+       .align 8;
+       [P4] = R5;
+       SSYNC;
+       STI R1;
+
+       r0 = sp;        /* stack frame pt_regs pointer argument ==> r0 */
+       r1 = RETX;
+
+       SP += -12;
+       call _early_trap_c;
+       SP += 12;
+ENDPROC(_early_trap)
+#endif /* CONFIG_EARLY_PRINTK */
 
 /*
  * Put these in the kernel data section - that should always be covered by
index 19534c1..139b520 100644 (file)
@@ -22,6 +22,7 @@ asmlinkage void evt_system_call(void);
 asmlinkage void init_exception_buff(void);
 asmlinkage void trap_c(struct pt_regs *fp);
 asmlinkage void ex_replaceable(void);
+asmlinkage void early_trap(void);
 
 extern void *ex_table[];
 extern void return_from_exception(void);