[PATCH 19/32] Blackfin arch: document why we have to touch the UART peripheral in our boot up code

[Bryan Wu <bryan.wu@analog.com>]

From: Mike Frysinger <michael.frysinger@analog.com>

Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
---
 arch/blackfin/mach-bf533/head.S |    3 ++-
 arch/blackfin/mach-bf537/head.S |    3 ++-
 arch/blackfin/mach-bf561/head.S |    3 ++-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/blackfin/mach-bf533/head.S b/arch/blackfin/mach-bf533/head.S
index 1a54ff5..4db9e62 100644
--- a/arch/blackfin/mach-bf533/head.S
+++ b/arch/blackfin/mach-bf533/head.S
@@ -173,7 +173,8 @@ ENTRY(__stext)
 	STI R2;
 #endif
 
-	/* Initialise UART */
+	/* Initialise UART - when booting from u-boot, the UART is not disabled
+	 * so if we dont initalize here, our serial console gets hosed */
 	p0.h = hi(UART_LCR);
 	p0.l = lo(UART_LCR);
 	r0 = 0x0(Z);
diff --git a/arch/blackfin/mach-bf537/head.S b/arch/blackfin/mach-bf537/head.S
index aafc686..b4377dd 100644
--- a/arch/blackfin/mach-bf537/head.S
+++ b/arch/blackfin/mach-bf537/head.S
@@ -181,7 +181,8 @@ ENTRY(__stext)
 	SSYNC;
 #endif
 
-	/*Initialise UART*/
+	/* Initialise UART - when booting from u-boot, the UART is not disabled
+	 * so if we dont initalize here, our serial console gets hosed */
 	p0.h = hi(UART_LCR);
 	p0.l = lo(UART_LCR);
 	r0 = 0x0(Z);
diff --git a/arch/blackfin/mach-bf561/head.S b/arch/blackfin/mach-bf561/head.S
index 04f3ac3..9c8e688 100644
--- a/arch/blackfin/mach-bf561/head.S
+++ b/arch/blackfin/mach-bf561/head.S
@@ -127,7 +127,8 @@ ENTRY(__stext)
 	STI R2;
 #endif
 
-	/* Initialise UART*/
+	/* Initialise UART - when booting from u-boot, the UART is not disabled
+	 * so if we dont initalize here, our serial console gets hosed */
 	p0.h = hi(UART_LCR);
 	p0.l = lo(UART_LCR);
 	r0 = 0x0(Z);
-- 
1.5.1.2
-
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