From d2d2e3c46be5d6dd8001d0eebdf7cafb9bc7006b Mon Sep 17 00:00:00 2001 From: Heikki Krogerus Date: Thu, 21 Jun 2018 16:43:17 +0300 Subject: acpi: Add helper for deactivating memory region Sometimes memory resource may be overlapping with SystemMemory Operation Region by design, for example if the memory region is used as a mailbox for communication with a firmware in the system. One occasion of such mailboxes is USB Type-C Connector System Software Interface (UCSI). With regions like that, it is important that the driver is able to map the memory with the requirements it has. For example, the driver should be allowed to map the memory as non-cached memory. However, if the operation region has been accessed before the driver has mapped the memory, the memory has been marked as write-back by the time the driver is loaded. That means the driver will fail to map the memory if it expects non-cached memory. To work around the problem, introducing helper that the drivers can use to temporarily deactivate (unmap) SystemMemory Operation Regions that overlap with their IO memory. Fixes: 8243edf44152 ("usb: typec: ucsi: Add ACPI driver") Cc: stable@vger.kernel.org Reviewed-by: Rafael J. Wysocki Signed-off-by: Heikki Krogerus Signed-off-by: Greg Kroah-Hartman --- include/linux/acpi.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include') diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 4b35a66383f9..e54f40974eb0 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -443,6 +443,9 @@ int acpi_check_resource_conflict(const struct resource *res); int acpi_check_region(resource_size_t start, resource_size_t n, const char *name); +acpi_status acpi_release_memory(acpi_handle handle, struct resource *res, + u32 level); + int acpi_resources_are_enforced(void); #ifdef CONFIG_HIBERNATION -- cgit v1.2.3