[U-Boot] [PATCH 1/4] x86: Make sure i8254 is setup correctly before generating beeps

[Bin Meng]

The i8254 timer control IO port (0x43) should be setup correctly
by using PIT counter 2 to generate beeps, however in U-Boot other
codes like TSC driver utilizes PIT for TSC frequency calibration
and configures the counter 2 to a different mode that does not
beep. Fix this by always ensuring the PIT counter 2 is correctly
initialized so that the i8254 beeper driver works as expected.

Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
---

 arch/x86/lib/i8254.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/lib/i8254.c b/arch/x86/lib/i8254.c
index d022795..0f97538 100644
--- a/arch/x86/lib/i8254.c
+++ b/arch/x86/lib/i8254.c
@@ -51,6 +51,10 @@ int i8254_enable_beep(uint frequency_hz)
 	if (!frequency_hz)
 		return -EINVAL;
 
+	/* make sure i8254 is setup correctly before generating beeps */
+	outb(PIT_CMD_CTR2 | PIT_CMD_BOTH | PIT_CMD_MODE3,
+	     PIT_BASE + PIT_COMMAND);
+
 	i8254_set_beep_freq(frequency_hz);
 	setio_8(SYSCTL_PORTB, PORTB_BEEP_ENABLE);
 
-- 
2.7.4