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| author | Nico Huber <nico.h@gmx.de> | 2020-11-01 19:36:48 +0100 |
|---|---|---|
| committer | Hung-Te Lin <hungte@chromium.org> | 2020-12-24 08:18:41 +0000 |
| commit | a160d93dda188b33b4b28bb888bd78120e42695d (patch) | |
| tree | 4fa8a73248e4fbf6fafb7e0db559cf2f8ded1e5f /payloads/libpayload | |
| parent | f651022df366565871ca28bff644c049f46bcf0e (diff) | |
| download | coreboot-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/libpayload')
| -rw-r--r-- | payloads/libpayload/drivers/i8042/keyboard.c | 27 |
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) |