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authorTom Rini <trini@konsulko.com>2015-11-13 10:02:43 -0500
committerTom Rini <trini@konsulko.com>2015-11-13 10:02:43 -0500
commitb67dfc5a1099eef2a323de23a78ba4e6d9b87633 (patch)
treee23ed37c2736481bd5cbf58f4d8aab57381005e9 /arch/x86/lib/i8254.c
parent439fcb9b4f717f5a583014acb3e75b789564867c (diff)
parent6d41027fe2e734aa1e15fabc1523417b3b871691 (diff)
Merge branch 'master' of git://git.denx.de/u-boot-x86
Diffstat (limited to 'arch/x86/lib/i8254.c')
-rw-r--r--arch/x86/lib/i8254.c37
1 files changed, 37 insertions, 0 deletions
diff --git a/arch/x86/lib/i8254.c b/arch/x86/lib/i8254.c
new file mode 100644
index 0000000000..46a4245289
--- /dev/null
+++ b/arch/x86/lib/i8254.c
@@ -0,0 +1,37 @@
+/*
+ * (C) Copyright 2002
+ * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/i8254.h>
+
+#define TIMER1_VALUE 18 /* 15.6us */
+#define TIMER2_VALUE 0x0a8e /* 440Hz */
+
+int i8254_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.
+ */
+ outb(PIT_CMD_CTR2 | PIT_CMD_BOTH | PIT_CMD_MODE3,
+ PIT_BASE + PIT_COMMAND);
+ outb(TIMER2_VALUE & 0xff, PIT_BASE + PIT_T2);
+ outb(TIMER2_VALUE >> 8, PIT_BASE + PIT_T2);
+
+ return 0;
+}