[PATCH] lib: sbi: print before sbi_console_init

[Xiang W]

The information from the print is cached via a ring buffer and
output to the console after initialization is complete.

Signed-off-by: Xiang W <wxjstz at 126.com>
---
 lib/sbi/sbi_console.c | 32 ++++++++++++++++++++++++++++++++
 lib/sbi/sbi_hart.c    |  4 ++++
 2 files changed, 36 insertions(+)

diff --git a/lib/sbi/sbi_console.c b/lib/sbi/sbi_console.c
index d3ec461..93e243a 100644
--- a/lib/sbi/sbi_console.c
+++ b/lib/sbi/sbi_console.c
@@ -19,6 +19,8 @@
 static const struct sbi_console_device *console_dev = NULL;
 static char console_tbuf[CONSOLE_TBUF_MAX];
 static u32 console_tbuf_len;
+static u32 console_tbuf_stat;
+static u32 console_tbuf_i;
 static spinlock_t console_out_lock	       = SPIN_LOCK_INITIALIZER;
 
 bool sbi_isprintable(char c)
@@ -135,6 +137,24 @@ static void printc(char **out, u32 *out_len, char ch, int flags)
 		return;
 	}
 
+	/* early print before console sbi_console_init */
+	if (!console_dev && (flags & USE_TBUF)) {
+		/*
+		 * console_tbuf_stat
+		 *   0 buff is empty
+		 *   1 buff is not empty and does not overflow
+		 *   2 buff is overflow
+		 */
+		console_tbuf [console_tbuf_i++] = ch;
+		if (console_tbuf_stat == 0)
+			console_tbuf_stat = 1;
+		if (console_tbuf_i == CONSOLE_TBUF_MAX) {
+			console_tbuf_stat = 2;
+			console_tbuf_i = 0;
+		}
+		return;
+	}
+
 	/*
 	 * The *printf entry point functions have enforced that (*out) can
 	 * only be null when out_len is non-null and its value is zero.
@@ -476,6 +496,18 @@ void sbi_console_set_device(const struct sbi_console_device *dev)
 		return;
 
 	console_dev = dev;
+
+	if (console_tbuf_stat == 1)
+		sbi_nputs(console_tbuf, console_tbuf_i);
+
+	if (console_tbuf_stat == 2) {
+		sbi_nputs(console_tbuf + console_tbuf_i,
+				CONSOLE_TBUF_MAX - console_tbuf_i);
+		sbi_nputs(console_tbuf, console_tbuf_i);
+	}
+
+	console_tbuf_stat = 0;
+	console_tbuf_i = 0;
 }
 
 int sbi_console_init(struct sbi_scratch *scratch)
diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
index c366701..48ec97c 100644
--- a/lib/sbi/sbi_hart.c
+++ b/lib/sbi/sbi_hart.c
@@ -1010,6 +1010,10 @@ int sbi_hart_init(struct sbi_scratch *scratch, bool cold_boot)
 
 void __attribute__((noreturn)) sbi_hart_hang(void)
 {
+	/* Try to initialize the console to output some error messages */
+	if (sbi_console_get_device() == NULL)
+		sbi_console_init(sbi_scratch_thishart_ptr());
+
 	while (1)
 		wfi();
 	__builtin_unreachable();
-- 
2.43.0