This patch adds support for calling panic() before stdio is initialized.
At present this will just hang with little or no indication of what the
problem is.
A new board_panic_no_console() function is added to the board API. If provided
by the board it will be called in the event of a panic before the console is
ready. This function should turn on all UARTS and spray the message out if
it possibly can.
The feature is controlled by a new CONFIG_PRE_CONSOLE_PANIC option.
Signed-off-by: Simon Glass <s...@chromium.org>
---
Changes in v2:
- Made this feature conditional on CONFIG_PRE_CONSOLE_PANIC
README | 11 +++++++++++
include/common.h | 8 ++++++++
lib/vsprintf.c | 29 +++++++++++++++++++++++++++++
3 files changed, 48 insertions(+), 0 deletions(-)
diff --git a/README b/README
index eb9ade9..0748a6f 100644
--- a/README
+++ b/README
@@ -634,6 +634,17 @@ The following options need to be configured:
'Sane' compilers will generate smaller code if
CONFIG_PRE_CON_BUF_SZ is a power of 2
+- Pre-console Panic:
+ Prior to the console being initialised, since console output
+ is silently discarded, a panic() will cause no output and no
+ indication of what is wrong. However, if the
+ CONFIG_PRE_CONSOLE_PANIC option is defined, then U-Boot will
+ call board_panic_no_console() in this case, passing the panic
+ message. This function should try to output the message if
+ possible, perhaps on all available UARTs (it will need to do
+ this directly, since the console code is not functional yet).
+ Another option is to flash some LEDs to indicate a panic.
+
- Boot Delay: CONFIG_BOOTDELAY - in seconds
Delay before automatically booting the default image;
set to -1 to disable autoboot.
diff --git a/include/common.h b/include/common.h
index 4c3e3a6..acc4030 100644
--- a/include/common.h
+++ b/include/common.h
@@ -277,6 +277,14 @@ int last_stage_init(void);
extern ulong monitor_flash_len;
int mac_read_from_eeprom(void);
+/*
+ * Called during a panic() when no console is available. The board should do
+ * its best to get a message to the user any way it can. This function should
+ * return if it can, in which case the system will either hang or reset.
+ * See panic().
+ */
+void board_panic_no_console(const char *str);
+
/* common/flash.c */
void flash_perror (int);
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 79dead3..56a2aef 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -24,6 +24,8 @@
# define NUM_TYPE long long
#define noinline __attribute__((noinline))
+DECLARE_GLOBAL_DATA_PTR;
+
const char hex_asc[] = "0123456789abcdef";
#define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
#define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
@@ -714,12 +716,39 @@ int sprintf(char * buf, const char *fmt, ...)
return i;
}
+#ifdef CONFIG_PRE_CONSOLE_PANIC
+/* Provide a default function for when no console is available */
+static void __board_panic_no_console(const char *msg)
+{
+ /* Just return since we can't access the console */
+}
+
+void board_panic_no_console(const char *msg) __attribute__((weak,
+ alias("__board_panic_no_console")));
+#endif
+
void panic(const char *fmt, ...)
{
va_list args;
+
va_start(args, fmt);
+#ifdef CONFIG_PRE_CONSOLE_PANIC
+ {
+ char str[CONFIG_SYS_PBSIZE];
+
+ /* TODO)sjg): Move to vsnprintf() when available */
+ vsprintf(str, fmt, args);
+ if (gd->have_console) {
+ puts(str);
+ putc('\n');
+ } else {
+ board_panic_no_console(str);
+ }
+ }
+#else
vprintf(fmt, args);
putc('\n');
+#endif
va_end(args);
#if defined (CONFIG_PANIC_HANG)
hang();
--
1.7.3.1
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