[U-Boot] [PATCH 3/5] input: i8042: Provide feature to disable keyboard before booting kernel
Simon Glass
sjg at chromium.org
Fri Oct 12 03:15:51 CEST 2012
From: Louis Yung-Chieh Lo <yjlou at chromium.org>
The BIOS leaves the keyboard enabled during boot time so that any
keystroke would interfere kernel driver initialization.
Add a way to disable the keyboard to make sure no scancode will be
generated during the boot time. Note that the keyboard will be
re-enabled again after the kernel driver is up.
This code can be called from the board functions.
Signed-off-by: Louis Yung-Chieh Lo <yjlou at chromium.org>
Signed-off-by: Louis Yung-Chieh Lo <yjlou at chromium.org>
Signed-off-by: Simon Glass <sjg at chromium.org>
---
drivers/input/i8042.c | 38 ++++++++++++++++++++++++++++++++++++++
include/i8042.h | 13 +++++++++++++
2 files changed, 51 insertions(+), 0 deletions(-)
diff --git a/drivers/input/i8042.c b/drivers/input/i8042.c
index cae2d0a..6b51eb5 100644
--- a/drivers/input/i8042.c
+++ b/drivers/input/i8042.c
@@ -331,6 +331,44 @@ int __board_i8042_skip(void)
}
int board_i8042_skip(void) __attribute__((weak, alias("__board_i8042_skip")));
+void i8042_flush(void)
+{
+ int timeout;
+
+ /*
+ * The delay is to give the keyboard controller some time to fill the
+ * next byte.
+ */
+ while (1) {
+ timeout = 100; /* wait for no longer than 100us */
+ while (timeout > 0 && !(in8(I8042_STATUS_REG) & 0x01)) {
+ udelay(1);
+ timeout--;
+ }
+
+ /* Try to pull next byte if not timeout. */
+ if (in8(I8042_STATUS_REG) & 0x01)
+ in8(I8042_DATA_REG);
+ else
+ break;
+ }
+}
+
+int i8042_disable(void)
+{
+ if (kbd_input_empty() == 0)
+ return -1;
+
+ /* Disable keyboard */
+ out8(I8042_COMMAND_REG, 0xad);
+
+ if (kbd_input_empty() == 0)
+ return -1;
+
+ return 0;
+}
+
+
/*******************************************************************************
*
* i8042_kbd_init - reset keyboard and init state flags
diff --git a/include/i8042.h b/include/i8042.h
index 1395289..c3e4e02 100644
--- a/include/i8042.h
+++ b/include/i8042.h
@@ -69,6 +69,19 @@
/* exports */
+/**
+ * Flush all buffer from keyboard controller to host.
+ */
+void i8042_flush(void);
+
+/**
+ * Disables the keyboard so that key strokes no longer generate scancodes to
+ * the host.
+ *
+ * @return 0 if ok, -1 if keyboard input was found while disabling
+ */
+int i8042_disable(void);
+
int i8042_kbd_init(void);
int i8042_tstc(void);
int i8042_getc(void);
--
1.7.7.3
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