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From:   Jiaxun Yang <jiaxun.yang@flygoat.com>
Date:   Sun, 29 Oct 2023 02:53:04 +0000
Subject: [PATCH 3/8] MIPS: debug: Hook up DEBUG_LL with early printk
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Message-Id: <20231029-mips_debug_ll-v1-3-d7a491e8c278@flygoat.com>
References: <20231029-mips_debug_ll-v1-0-d7a491e8c278@flygoat.com>
In-Reply-To: <20231029-mips_debug_ll-v1-0-d7a491e8c278@flygoat.com>
To:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc:     linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jiaxun Yang <jiaxun.yang@flygoat.com>
Precedence: bulk

Output earlyprintk to low-level debug functions when it's
available.

DEBUG_LL takes priority over platform earlyprintk because
people must know what are they doing when they are trying
to enable DEBUG_LL.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
 arch/mips/Kconfig.debug         |  2 +-
 arch/mips/kernel/early_printk.c | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/mips/Kconfig.debug b/arch/mips/Kconfig.debug
index 892e31804982..6ef42edc7d67 100644
--- a/arch/mips/Kconfig.debug
+++ b/arch/mips/Kconfig.debug
@@ -2,7 +2,7 @@
 
 config EARLY_PRINTK
 	bool "Early printk" if EXPERT
-	depends on SYS_HAS_EARLY_PRINTK
+	depends on SYS_HAS_EARLY_PRINTK || DEBUG_LL
 	default y
 	help
 	  This option enables special console drivers which allow the kernel
diff --git a/arch/mips/kernel/early_printk.c b/arch/mips/kernel/early_printk.c
index 4a1647ddfbd9..c3f3b0a930f0 100644
--- a/arch/mips/kernel/early_printk.c
+++ b/arch/mips/kernel/early_printk.c
@@ -14,6 +14,24 @@
 
 #include <asm/setup.h>
 
+#ifdef CONFIG_DEBUG_LL
+extern void printascii(const char *);
+
+static void early_console_write(struct console *con, const char *s, unsigned n)
+{
+	char buf[128];
+
+	while (n) {
+		unsigned int l = min(n, sizeof(buf)-1);
+
+		memcpy(buf, s, l);
+		buf[l] = 0;
+		s += l;
+		n -= l;
+		printascii(buf);
+	}
+}
+#else
 static void early_console_write(struct console *con, const char *s, unsigned n)
 {
 	while (n-- && *s) {
@@ -23,6 +41,7 @@ static void early_console_write(struct console *con, const char *s, unsigned n)
 		s++;
 	}
 }
+#endif
 
 static struct console early_console_prom = {
 	.name	= "early",

-- 
2.34.1