Commit Graph

2 Commits

Author SHA1 Message Date
Alex Van Damme
d737e80b17 Enable Apex on ARM64, fix compile issue
- Change from X86 only to X86 or ARM64 in Kconfig
- refcount_read doesn't exist in 4.11, so use atomic_read instead. This
is the same call that refcount_read in 4.12+ would make.

Change-Id: I48c97dd8c14136dcccaa8378b3a931a7872e1289
2018-07-23 16:11:14 -07:00
Simon Que
0305c1f77f drivers/staging: Gasket driver framework + Apex driver
The Gasket (Google ASIC Software, Kernel Extensions, and Tools) kernel
framework is a generic, flexible system that supports thin kernel
drivers. Gasket kernel drivers are expected to handle opening and
closing devices, mmap'ing BAR space as requested, a small selection of
ioctls, and handling page table translation (covered below). Any other
functions should be handled by userspace code.

The Gasket common module is not enough to run a device. In order to
customize the Gasket code for a given piece of hardware, a device
specific module must be created. At a minimum, this module must define a
struct gasket_driver_desc containing the device-specific data for use by
the framework; in addition, the module must declare an __init function
that calls gasket_register_device with the module's gasket_driver_desc
struct. Finally, the driver must define an exit function that calls
gasket_unregister_device with the module's gasket_driver_desc struct.

One of the core assumptions of the Gasket framework is that precisely
one process is allowed to have an open write handle to the device node
at any given time. (That process may, once it has one write handle, open
any number of additional write handles.) This is accomplished by
tracking open and close data for each driver instance.

Change-Id: I0ce1dc1dc9c533026adbc3aacaefb830ecdbc3e9
Signed-off-by: Rob Springer <rspringer@google.com>
Signed-off-by: John Joseph <jnjoseph@google.com>
Signed-off-by: Simon Que <sque@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-23 16:08:19 -07:00