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authorNico Huber <nico.h@gmx.de>2020-11-01 19:36:48 +0100
committerHung-Te Lin <hungte@chromium.org>2020-12-24 08:18:41 +0000
commita160d93dda188b33b4b28bb888bd78120e42695d (patch)
tree4fa8a73248e4fbf6fafb7e0db559cf2f8ded1e5f /payloads
parentf651022df366565871ca28bff644c049f46bcf0e (diff)
downloadcoreboot-a160d93dda188b33b4b28bb888bd78120e42695d.tar.xz
libpayload/keyboard: Revise keyboard_cmd() error handling
Even if we are careful, it's still possible that we read spurious data from the keyboard, e.g. keystrokes. Namely, when we send the reset/disable command, there is a race before the command is pro- cessed. So we should always process data from the keyboard in a loop. We break it, when an ACK (0xfa) or a NAK (0xfe) is received, and warn on unexpected data unless it might be due to the mentioned race. This also gives us the opportunity to use command-specific timeouts which we take from Linux: 1s for the keyboard self-test (as there are keyboards that perform the test before acking the command) and 200ms for all other commands. Change-Id: I60a2643a8ff4b9231c63bf970c8749c97c7d8926 Signed-off-by: Nico Huber <nico.h@gmx.de> Reviewed-on: https://review.coreboot.org/c/coreboot/+/47083 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Diffstat (limited to 'payloads')
-rw-r--r--payloads/libpayload/drivers/i8042/keyboard.c27
1 files changed, 26 insertions, 1 deletions
diff --git a/payloads/libpayload/drivers/i8042/keyboard.c b/payloads/libpayload/drivers/i8042/keyboard.c
index 22747ff79d..42d4fdccf5 100644
--- a/payloads/libpayload/drivers/i8042/keyboard.c
+++ b/payloads/libpayload/drivers/i8042/keyboard.c
@@ -28,6 +28,7 @@
*/
#include <stdbool.h>
+#include <stdint.h>
#include <keycodes.h>
#include <libpayload-config.h>
@@ -173,9 +174,33 @@ static struct layout_maps keyboard_layouts[] = {
static bool keyboard_cmd(unsigned char cmd)
{
+ const uint64_t timeout_us = cmd == I8042_KBCMD_RESET ? 1*1000*1000 : 200*1000;
+ const uint64_t start_time = timer_us(0);
+
i8042_write_data(cmd);
- return i8042_wait_read_ps2() == 0xfa;
+ do {
+ if (!i8042_data_ready_ps2()) {
+ udelay(50);
+ continue;
+ }
+
+ const uint8_t data = i8042_read_data_ps2();
+ switch (data) {
+ case 0xfa:
+ return true;
+ case 0xfe:
+ return false;
+ default:
+ /* Warn only if we already disabled keyboard input. */
+ if (cmd != I8042_KBCMD_DEFAULT_DIS)
+ printf("WARNING: Keyboard sent spurious 0x%02x.\n", data);
+ break;
+ }
+ } while (timer_us(start_time) < timeout_us);
+
+ printf("ERROR: Keyboard command timed out.\n");
+ return false;
}
bool keyboard_havechar(void)