diff options
| author | Vincent Palatin <vpalatin@chromium.org> | 2012-05-25 15:56:55 +0000 |
|---|---|---|
| committer | Vincent Palatin <vpalatin@chromium.org> | 2012-05-25 16:04:50 +0000 |
| commit | 38bab6b9f1fc74d53960b62054792f7885fd994a (patch) | |
| tree | 074417d56830e725fd0fe74d7793cc2a522af4b0 /chip | |
| parent | 61902efd16095af85764bd4b2df51415df49ea55 (diff) | |
| download | chrome-ec-38bab6b9f1fc74d53960b62054792f7885fd994a.tar.gz | |
stm32: fix keyboard FIFO
When the FIFO is empty, returns the last read entry not the next one.
also rewrite the FIFO index increment to generate slightly better code.
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
BUG=chrome-os-partner:8869
TEST=On Snow, in U-Boot using "stdin=mkbp-keyb" type on internal
keyboard and see the correct text.
Change-Id: I189d230053de40dd563ce672db82dd6217e545e3
Diffstat (limited to 'chip')
| -rw-r--r-- | chip/stm32/keyboard_scan.c | 22 |
1 files changed, 9 insertions, 13 deletions
diff --git a/chip/stm32/keyboard_scan.c b/chip/stm32/keyboard_scan.c index 2784ae1dc2..3a302969e0 100644 --- a/chip/stm32/keyboard_scan.c +++ b/chip/stm32/keyboard_scan.c @@ -76,8 +76,8 @@ void board_keyboard_suppress_noise(void) __attribute__((weak, alias("__board_keyboard_suppress_noise"))); #define KB_FIFO_DEPTH 16 /* FIXME: this is pretty huge */ -static int kb_fifo_start; /* first entry */ -static int kb_fifo_end; /* last entry */ +static uint32_t kb_fifo_start; /* first entry */ +static uint32_t kb_fifo_end; /* last entry */ static uint32_t kb_fifo_entries; /* number of existing entries */ static uint8_t kb_fifo[KB_FIFO_DEPTH][KB_OUTPUTS]; @@ -111,10 +111,7 @@ static int kb_fifo_add(uint8_t *buffp) memcpy(kb_fifo[kb_fifo_end], buffp, KB_OUTPUTS); - if (kb_fifo_end == KB_FIFO_DEPTH - 1) - kb_fifo_end = 0; - else - kb_fifo_end++; + kb_fifo_end = (kb_fifo_end + 1) % KB_FIFO_DEPTH; atomic_add(&kb_fifo_entries, 1); @@ -129,10 +126,11 @@ kb_fifo_push_done: */ static int kb_fifo_remove(uint8_t *buffp) { - memcpy(buffp, kb_fifo[kb_fifo_start], KB_OUTPUTS); - if (!kb_fifo_entries) { - CPRINTF("%s: No entries remaining in FIFO\n", __func__); + /* no entry remaining in FIFO : return last known state */ + memcpy(buffp, kb_fifo[(kb_fifo_start - 1) % KB_FIFO_DEPTH], + KB_OUTPUTS); + /* * Bail out without changing any FIFO indices and let the * caller know something strange happened. The buffer will @@ -140,11 +138,9 @@ static int kb_fifo_remove(uint8_t *buffp) */ return EC_ERROR_UNKNOWN; } + memcpy(buffp, kb_fifo[kb_fifo_start], KB_OUTPUTS); - if (kb_fifo_start == KB_FIFO_DEPTH - 1) - kb_fifo_start = 0; - else - kb_fifo_start++; + kb_fifo_start = (kb_fifo_start + 1) % KB_FIFO_DEPTH; atomic_sub(&kb_fifo_entries, 1); |