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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 /include/host_command.h | |
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 'include/host_command.h')
-rw-r--r-- | include/host_command.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/include/host_command.h b/include/host_command.h index 4bf903e6ef..f95fe06966 100644 --- a/include/host_command.h +++ b/include/host_command.h @@ -124,6 +124,20 @@ struct host_command { uint8_t *host_get_memmap(int offset); /** + * Grab the memmap write mutex. This function should be called before + * multi-byte variable reads from ACPI, and before updating multi-byte + * memmap variables anywhere else. + */ +void host_lock_memmap(void); + +/** + * Release the memmap write mutex. This function should be called once + * a multi-byte variable read from ACPI is done, and when updating multi-byte + * memmap variables is done. + */ +void host_unlock_memmap(void); + +/** * Process a host command and return its response * * @param args Command handler args |