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input: Flush the keyboard buffer before resetting it

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If U-Boot is not the first-stage bootloader the keyboard may already be
set up. Make sure to flush any data before trying to reset it. This
avoids a long timeout / hang.

Add some comments and a log category while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
This commit is contained in:
Simon Glass
2023-05-04 16:54:56 -06:00
committed by Bin Meng
parent 7a187a89fd
commit d8062e9503
1 changed files with 19 additions and 0 deletions
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19
drivers/input/i8042.c
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@@ -6,6 +6,8 @@
/* i8042.c - Intel 8042 keyboard driver routines */
#define LOG_CATEGORY UCLASS_KEYBOARD
#include <common.h>
#include <dm.h>
#include <env.h>
@@ -54,6 +56,14 @@ static unsigned char ext_key_map[] = {
0x00 /* map end */
};
/**
* kbd_input_empty() - Wait until the keyboard is ready for a command
*
* Checks the IBF flag (input buffer full), waiting for it to indicate that
* any previous command has been processed.
*
* Return: true if ready, false if it timed out
*/
static int kbd_input_empty(void)
{
int kbd_timeout = KBD_TIMEOUT * 1000;
@@ -64,6 +74,12 @@ static int kbd_input_empty(void)
return kbd_timeout != -1;
}
/**
* kbd_output_full() - Wait until the keyboard has data available
*
* Checks the OBF flag (output buffer full), waiting for it to indicate that
* a response to a previous command is available
*/
static int kbd_output_full(void)
{
int kbd_timeout = KBD_TIMEOUT * 1000;
@@ -127,6 +143,9 @@ static int kbd_reset(int quirk)
{
int config;
if (!kbd_input_empty())
goto err;
/* controller self test */
if (kbd_cmd_read(CMD_SELF_TEST) != KBC_TEST_OK)
goto err;