diff options
| author | Shawn Nematbakhsh <shawnn@chromium.org> | 2015-03-23 18:27:22 -0700 |
|---|---|---|
| committer | ChromeOS Commit Bot <chromeos-commit-bot@chromium.org> | 2015-03-25 20:09:52 +0000 |
| commit | 6ee7b1e34eecd585074b4aae0347ed12f632ead0 (patch) | |
| tree | ace73f958495a83b836505941318325fa71c71e7 /common/fan.c | |
| parent | 0f18989ef58a77800c1b393cf8223455f793d543 (diff) | |
| download | chrome-ec-6ee7b1e34eecd585074b4aae0347ed12f632ead0.tar.gz | |
ACPI: Support accessing memmap data over ACPI CMD / DATA portsstabilize-6915.B
Some platforms are unable to access the 900h-9ffh region over LPC and
must instead access memmap data through the ACPI CMD / DATA ports. To
avoid racing with data updates, disallow changes to multi-byte memmap
data while in burst mode.
Linux currently enables burst mode when accessing multi-byte data and
disables it immediately afterward, though the ACPI spec defines burst mode
in a more general way.
BUG=chrome-os-partner:38224
TEST=Manual on Samus. Undefine LPC_MEMMAP and modify asl to move memmap
data to ERAM at offset 0x20. Verify system boots cleanly and battery
status is updated immediately on plug / unplug.
BRANCH=None
Change-Id: Ib848bdb491fdfece96ad0cee7a44ba85b4a1a50b
Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/262072
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Diffstat (limited to 'common/fan.c')
| -rw-r--r-- | common/fan.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/common/fan.c b/common/fan.c index 9196ddf36b..6cb64e777a 100644 --- a/common/fan.c +++ b/common/fan.c @@ -471,17 +471,23 @@ DECLARE_HOOK(HOOK_INIT, pwm_fan_init, HOOK_PRIO_DEFAULT); static void pwm_fan_second(void) { uint16_t *mapped = (uint16_t *)host_get_memmap(EC_MEMMAP_FAN); + uint16_t rpm; int stalled = 0; int fan; for (fan = 0; fan < CONFIG_FANS; fan++) { if (fan_is_stalled(fans[fan].ch)) { - mapped[fan] = EC_FAN_SPEED_STALLED; + rpm = EC_FAN_SPEED_STALLED; stalled = 1; cprints(CC_PWM, "Fan %d stalled!", fan); } else { - mapped[fan] = fan_get_rpm_actual(fans[fan].ch); + rpm = fan_get_rpm_actual(fans[fan].ch); } + + /* Lock ACPI read access to memmap during multi-byte write */ + host_lock_memmap(); + mapped[fan] = rpm; + host_unlock_memmap(); } /* |