[U-Boot] [PATCH v2 4/8] x86: Initialize i8254 timer counter 1
Bin Meng
bmeng.cn at gmail.com
Fri Oct 23 04:13:29 CEST 2015
Initialize counter 1, used to refresh request signal. This is
required for legacy purpose as some codes like vgabios utilizes
counter 1 to provide delay functionality.
Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
Acked-by: Simon Glass <sjg at chromium.org>
---
Changes in v2: None
arch/x86/lib/pcat_timer.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/x86/lib/pcat_timer.c b/arch/x86/lib/pcat_timer.c
index ce15818..347cdda 100644
--- a/arch/x86/lib/pcat_timer.c
+++ b/arch/x86/lib/pcat_timer.c
@@ -9,11 +9,21 @@
#include <asm/io.h>
#include <asm/i8254.h>
+#define TIMER1_VALUE 18 /* 15.6us */
#define TIMER2_VALUE 0x0a8e /* 440Hz */
int pcat_timer_init(void)
{
/*
+ * Initialize counter 1, used to refresh request signal.
+ * This is required for legacy purpose as some codes like
+ * vgabios utilizes counter 1 to provide delay functionality.
+ */
+ outb(PIT_CMD_CTR1 | PIT_CMD_LOW | PIT_CMD_MODE2,
+ PIT_BASE + PIT_COMMAND);
+ outb(TIMER1_VALUE, PIT_BASE + PIT_T1);
+
+ /*
* Initialize counter 2, used to drive the speaker.
* To start a beep, set both bit0 and bit1 of port 0x61.
* To stop it, clear both bit0 and bit1 of port 0x61.
--
1.8.2.1
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