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.

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>

1 files changed, 35 insertions, 0 deletions

diff --git a/drivers/staging/gasket/gasket_ioctl.h b/drivers/staging/gasket/gasket_ioctl.h
new file mode 100644
index 000000000000..df868000c803
--- /dev/null
+++ b/drivers/staging/gasket/gasket_ioctl.h
@@ -0,0 +1,35 @@
+/* Copyright (C) 2018 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#ifndef __GASKET_IOCTL_H__
+#define __GASKET_IOCTL_H__
+
+#include "gasket_core.h"
+
+/*
+ * Handle Gasket common ioctls.
+ * @filp: Pointer to the ioctl's file.
+ * @cmd: Ioctl command.
+ * @arg: Ioctl argument pointer.
+ *
+ * Returns 0 on success and nonzero on failure.
+ */
+long gasket_handle_ioctl(struct file *filp, uint cmd, ulong arg);
+
+/*
+ * Determines if an ioctl is part of the standard Gasket framework.
+ * @cmd: The ioctl number to handle.
+ *
+ * Returns 1 if the ioctl is supported and 0 otherwise.
+ */
+long gasket_is_supported_ioctl(uint cmd);
+
+#endif