Add and use plat_crash_console_flush() API

This API makes sure that all the characters sent to the crash console
are output before returning from it.

Porting guide updated.

Change-Id: I1785f970a40f6aacfbe592b6a911b1f249bb2735
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

bl31/aarch64/crash_reporting.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014-2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2014-2017, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -349,6 +349,8 @@ func do_crash_reporting
 	/* Print some platform registers */
 	plat_crash_print_regs
 
+	bl	plat_crash_console_flush
+
 	/* Done reporting */
 	no_ret	plat_panic_handler
 endfunc do_crash_reporting

common/aarch32/debug.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -70,6 +70,9 @@ func do_panic
 	/* Print new line */
 	ldr	r4, =panic_end
 	bl	asm_print_str
+
+	bl	plat_crash_console_flush
+
 1:
 	mov	lr, r6
 	b	plat_panic_handler
@@ -140,6 +143,9 @@ dec_print_loop:
 	udiv	r5, r5, r6			/* Reduce divisor */
 	cmp	r5, #0
 	bne	dec_print_loop
+
+	bl	plat_crash_console_flush
+
 1:
 	no_ret	plat_panic_handler
 endfunc asm_assert

common/aarch64/debug.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014-2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2014-2017, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -96,6 +96,7 @@ func asm_assert
 	b.ne	_assert_loop
 	mov	x4, x6
 	asm_print_line_dec
+	bl	plat_crash_console_flush
 _assert_loop:
 	b	_assert_loop
 endfunc asm_assert
@@ -187,6 +188,8 @@ el3_panic:
 	sub	x4, x4, #4
 	bl	asm_print_hex
 
+	bl	plat_crash_console_flush
+
 _panic_handler:
 	/* Pass to plat_panic_handler the address from where el3_panic was
 	 * called, not the address of the call from el3_panic. */

docs/porting-guide.md

@@ -2228,6 +2228,17 @@ designated crash console. It must only use general purpose registers x1 and
 x2 to do its work. The parameter and the return value are in general purpose
 register x0.
 
+### Function : plat_crash_console_flush
+
+    Argument : void
+    Return   : int
+
+This API is used by the crash reporting mechanism to force write of all buffered
+data on the designated crash console. It should only use general purpose
+registers x0 and x1 to do its work. The return value is 0 on successful
+completion; otherwise the return value is -1.
+
+
 4.  Build flags
 ---------------
 

include/plat/common/platform.h

@@ -90,6 +90,7 @@ uintptr_t plat_get_my_stack(void);
 void plat_report_exception(unsigned int exception_type);
 int plat_crash_console_init(void);
 int plat_crash_console_putc(int c);
+int plat_crash_console_flush(void);
 void plat_error_handler(int err) __dead2;
 void plat_panic_handler(void) __dead2;
 

plat/arm/common/aarch32/arm_helpers.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -31,9 +31,10 @@
 #include <platform_def.h>
 
 	.weak	plat_arm_calc_core_pos
-	.weak	plat_crash_console_init
-	.weak	plat_crash_console_putc
 	.weak	plat_my_core_pos
+	.globl	plat_crash_console_init
+	.globl	plat_crash_console_putc
+	.globl	plat_crash_console_flush
 
 	/* -----------------------------------------------------
 	 *  unsigned int plat_my_core_pos(void)
@@ -85,3 +86,16 @@ func plat_crash_console_putc
 	ldr	r1, =PLAT_ARM_CRASH_UART_BASE
 	b	console_core_putc
 endfunc plat_crash_console_putc
+
+	/* ---------------------------------------------
+	 * int plat_crash_console_flush()
+	 * Function to force a write of all buffered
+	 * data that hasn't been output.
+	 * Out : return -1 on error else return 0.
+	 * Clobber list : r0 - r1
+	 * ---------------------------------------------
+	 */
+func plat_crash_console_flush
+	ldr	r1, =PLAT_ARM_CRASH_UART_BASE
+	b	console_core_flush
+endfunc plat_crash_console_flush

plat/arm/common/aarch64/arm_helpers.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2017, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -34,6 +34,7 @@
 	.weak	plat_my_core_pos
 	.globl	plat_crash_console_init
 	.globl	plat_crash_console_putc
+	.globl	plat_crash_console_flush
 	.globl	platform_mem_init
 
 
@@ -88,6 +89,19 @@ func plat_crash_console_putc
 	b	console_core_putc
 endfunc plat_crash_console_putc
 
+	/* ---------------------------------------------
+	 * int plat_crash_console_flush()
+	 * Function to force a write of all buffered
+	 * data that hasn't been output.
+	 * Out : return -1 on error else return 0.
+	 * Clobber list : r0 - r1
+	 * ---------------------------------------------
+	 */
+func plat_crash_console_flush
+	mov_imm	x1, PLAT_ARM_CRASH_UART_BASE
+	b	console_core_flush
+endfunc plat_crash_console_flush
+
 	/* ---------------------------------------------------------------------
 	 * We don't need to carry out any memory initialization on ARM
 	 * platforms. The Secure RAM is accessible straight away.

plat/common/aarch32/platform_helpers.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -31,11 +31,43 @@
 #include <arch.h>
 #include <asm_macros.S>
 
+	.weak	plat_crash_console_init
+	.weak	plat_crash_console_putc
+	.weak	plat_crash_console_flush
 	.weak	plat_reset_handler
 	.weak	plat_disable_acp
 	.weak	platform_mem_init
 	.weak	plat_panic_handler
 
+	/* -----------------------------------------------------
+	 * Placeholder function which should be redefined by
+	 * each platform.
+	 * -----------------------------------------------------
+	 */
+func plat_crash_console_init
+	mov	r0, #0
+	bx	lr
+endfunc plat_crash_console_init
+
+	/* -----------------------------------------------------
+	 * Placeholder function which should be redefined by
+	 * each platform.
+	 * -----------------------------------------------------
+	 */
+func plat_crash_console_putc
+	bx	lr
+endfunc plat_crash_console_putc
+
+	/* -----------------------------------------------------
+	 * Placeholder function which should be redefined by
+	 * each platform.
+	 * -----------------------------------------------------
+	 */
+func plat_crash_console_flush
+	mov	r0, #0
+	bx	lr
+endfunc plat_crash_console_flush
+
 	/* -----------------------------------------------------
 	 * Placeholder function which should be redefined by
 	 * each platform.

plat/common/aarch64/platform_helpers.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -35,6 +35,7 @@
 	.weak	plat_report_exception
 	.weak	plat_crash_console_init
 	.weak	plat_crash_console_putc
+	.weak	plat_crash_console_flush
 	.weak	plat_reset_handler
 	.weak	plat_disable_acp
 	.weak	bl1_plat_prepare_exit
@@ -96,6 +97,15 @@ func plat_crash_console_putc
 	ret
 endfunc plat_crash_console_putc
 
+	/* -----------------------------------------------------
+	 * Placeholder function which should be redefined by
+	 * each platform.
+	 * -----------------------------------------------------
+	 */
+func plat_crash_console_flush
+	ret
+endfunc plat_crash_console_flush
+
 	/* -----------------------------------------------------
 	 * Placeholder function which should be redefined by
 	 * each platform. This function should preserve x19 - x29.