[PATCH v2] staging: Android: Add 'vsoc' driver for cuttlefish.

[Alistair Strachan]

From: Greg Hartman 

The cuttlefish system is a virtual SoC architecture based on QEMU. It
uses the QEMU ivshmem feature to share memory regions between guest and
host with a custom protocol.

Cc: Greg Kroah-Hartman 
Cc: Arve Hjønnevåg 
Cc: Todd Kjos 
Cc: Martijn Coenen 
Cc: Dan Carpenter 
Cc: de...@driverdev.osuosl.org
Cc: kernel-t...@android.com
Signed-off-by: Greg Hartman 
[astrachan: rebased against 4.16, added TODO, fixed checkpatch issues]
Signed-off-by: Alistair Strachan 
---
v2: addressed issues with class_create() failure handling and redundant
null pointer checks noticed by Dan Carpenter

 drivers/staging/android/Kconfig |9 +
 drivers/staging/android/Makefile|1 +
 drivers/staging/android/TODO|   10 +
 drivers/staging/android/uapi/vsoc_shm.h |  303 ++
 drivers/staging/android/vsoc.c  | 1169 +++
 5 files changed, 1492 insertions(+)
 create mode 100644 drivers/staging/android/uapi/vsoc_shm.h
 create mode 100644 drivers/staging/android/vsoc.c

diff --git a/drivers/staging/android/Kconfig b/drivers/staging/android/Kconfig
index 71a50b99caff..29d891355f7a 100644
--- a/drivers/staging/android/Kconfig
+++ b/drivers/staging/android/Kconfig
@@ -14,6 +14,15 @@ config ASHMEM
  It is, in theory, a good memory allocator for low-memory devices,
  because it can discard shared memory units when under memory pressure.
 
+config ANDROID_VSOC
+   tristate "Android Virtual SoC support"
+   default n
+   depends on PCI_MSI
+   ---help---
+ This option adds support for the Virtual SoC driver needed to boot
+ a 'cuttlefish' Android image inside QEmu. The driver interacts with
+ a QEmu ivshmem device. If built as a module, it will be called vsoc.
+
 source "drivers/staging/android/ion/Kconfig"
 
 endif # if ANDROID
diff --git a/drivers/staging/android/Makefile b/drivers/staging/android/Makefile
index 7cf1564a49a5..90e6154f11a4 100644
--- a/drivers/staging/android/Makefile
+++ b/drivers/staging/android/Makefile
@@ -3,3 +3,4 @@ ccflags-y += -I$(src)   # needed for trace 
events
 obj-y  += ion/
 
 obj-$(CONFIG_ASHMEM)   += ashmem.o
+obj-$(CONFIG_ANDROID_VSOC) += vsoc.o
diff --git a/drivers/staging/android/TODO b/drivers/staging/android/TODO
index 687e0eac85bf..6aab759efa48 100644
--- a/drivers/staging/android/TODO
+++ b/drivers/staging/android/TODO
@@ -11,5 +11,15 @@ ion/
  - Split /dev/ion up into multiple nodes (e.g. /dev/ion/heap0)
  - Better test framework (integration with VGEM was suggested)
 
+vsoc.c, uapi/vsoc_shm.h
+ - The current driver uses the same wait queue for all of the futexes in a
+   region. This will cause false wakeups in regions with a large number of
+   waiting threads. We should eventually use multiple queues and select the
+   queue based on the region.
+ - Add debugfs support for examining the permissions of regions.
+ - Use ioremap_wc instead of ioremap_nocache.
+ - Remove VSOC_WAIT_FOR_INCOMING_INTERRUPT ioctl. This functionality has been
+   superseded by the futex and is there for legacy reasons.
+
 Please send patches to Greg Kroah-Hartman  and Cc:
 Arve Hjønnevåg  and Riley Andrews 
diff --git a/drivers/staging/android/uapi/vsoc_shm.h 
b/drivers/staging/android/uapi/vsoc_shm.h
new file mode 100644
index ..741b1387c25b
--- /dev/null
+++ b/drivers/staging/android/uapi/vsoc_shm.h
@@ -0,0 +1,303 @@
+/*
+ * Copyright (C) 2017 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 _UAPI_LINUX_VSOC_SHM_H
+#define _UAPI_LINUX_VSOC_SHM_H
+
+#include 
+
+/**
+ * A permission is a token that permits a receiver to read and/or write an area
+ * of memory within a Vsoc region.
+ *
+ * An fd_scoped permission grants both read and write access, and can be
+ * attached to a file description (see open(2)).
+ * Ownership of the area can then be shared by passing a file descriptor
+ * among processes.
+ *
+ * begin_offset and end_offset define the area of memory that is controlled by
+ * the permission. owner_offset points to a word, also in shared memory, that
+ * controls ownership of the area.
+ *
+ * ownership of the region expires when the associated file description is
+ * released.
+ *
+ * At most one permission can be attached 

[PATCH v2] staging: Android: Add 'vsoc' driver for cuttlefish.

[Alistair Strachan]

From: Greg Hartman 

The cuttlefish system is a virtual SoC architecture based on QEMU. It
uses the QEMU ivshmem feature to share memory regions between guest and
host with a custom protocol.

Cc: Greg Kroah-Hartman 
Cc: Arve Hjønnevåg 
Cc: Todd Kjos 
Cc: Martijn Coenen 
Cc: Dan Carpenter 
Cc: de...@driverdev.osuosl.org
Cc: kernel-t...@android.com
Signed-off-by: Greg Hartman 
[astrachan: rebased against 4.16, added TODO, fixed checkpatch issues]
Signed-off-by: Alistair Strachan 
---
v2: addressed issues with class_create() failure handling and redundant
null pointer checks noticed by Dan Carpenter

 drivers/staging/android/Kconfig |9 +
 drivers/staging/android/Makefile|1 +
 drivers/staging/android/TODO|   10 +
 drivers/staging/android/uapi/vsoc_shm.h |  303 ++
 drivers/staging/android/vsoc.c  | 1169 +++
 5 files changed, 1492 insertions(+)
 create mode 100644 drivers/staging/android/uapi/vsoc_shm.h
 create mode 100644 drivers/staging/android/vsoc.c

diff --git a/drivers/staging/android/Kconfig b/drivers/staging/android/Kconfig
index 71a50b99caff..29d891355f7a 100644
--- a/drivers/staging/android/Kconfig
+++ b/drivers/staging/android/Kconfig
@@ -14,6 +14,15 @@ config ASHMEM
  It is, in theory, a good memory allocator for low-memory devices,
  because it can discard shared memory units when under memory pressure.
 
+config ANDROID_VSOC
+   tristate "Android Virtual SoC support"
+   default n
+   depends on PCI_MSI
+   ---help---
+ This option adds support for the Virtual SoC driver needed to boot
+ a 'cuttlefish' Android image inside QEmu. The driver interacts with
+ a QEmu ivshmem device. If built as a module, it will be called vsoc.
+
 source "drivers/staging/android/ion/Kconfig"
 
 endif # if ANDROID
diff --git a/drivers/staging/android/Makefile b/drivers/staging/android/Makefile
index 7cf1564a49a5..90e6154f11a4 100644
--- a/drivers/staging/android/Makefile
+++ b/drivers/staging/android/Makefile
@@ -3,3 +3,4 @@ ccflags-y += -I$(src)   # needed for trace 
events
 obj-y  += ion/
 
 obj-$(CONFIG_ASHMEM)   += ashmem.o
+obj-$(CONFIG_ANDROID_VSOC) += vsoc.o
diff --git a/drivers/staging/android/TODO b/drivers/staging/android/TODO
index 687e0eac85bf..6aab759efa48 100644
--- a/drivers/staging/android/TODO
+++ b/drivers/staging/android/TODO
@@ -11,5 +11,15 @@ ion/
  - Split /dev/ion up into multiple nodes (e.g. /dev/ion/heap0)
  - Better test framework (integration with VGEM was suggested)
 
+vsoc.c, uapi/vsoc_shm.h
+ - The current driver uses the same wait queue for all of the futexes in a
+   region. This will cause false wakeups in regions with a large number of
+   waiting threads. We should eventually use multiple queues and select the
+   queue based on the region.
+ - Add debugfs support for examining the permissions of regions.
+ - Use ioremap_wc instead of ioremap_nocache.
+ - Remove VSOC_WAIT_FOR_INCOMING_INTERRUPT ioctl. This functionality has been
+   superseded by the futex and is there for legacy reasons.
+
 Please send patches to Greg Kroah-Hartman  and Cc:
 Arve Hjønnevåg  and Riley Andrews 
diff --git a/drivers/staging/android/uapi/vsoc_shm.h 
b/drivers/staging/android/uapi/vsoc_shm.h
new file mode 100644
index ..741b1387c25b
--- /dev/null
+++ b/drivers/staging/android/uapi/vsoc_shm.h
@@ -0,0 +1,303 @@
+/*
+ * Copyright (C) 2017 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 _UAPI_LINUX_VSOC_SHM_H
+#define _UAPI_LINUX_VSOC_SHM_H
+
+#include 
+
+/**
+ * A permission is a token that permits a receiver to read and/or write an area
+ * of memory within a Vsoc region.
+ *
+ * An fd_scoped permission grants both read and write access, and can be
+ * attached to a file description (see open(2)).
+ * Ownership of the area can then be shared by passing a file descriptor
+ * among processes.
+ *
+ * begin_offset and end_offset define the area of memory that is controlled by
+ * the permission. owner_offset points to a word, also in shared memory, that
+ * controls ownership of the area.
+ *
+ * ownership of the region expires when the associated file description is
+ * released.
+ *
+ * At most one permission can be attached to each file description.
+ *
+ * This is useful when implementing HALs like gralloc that scope and pass
+ * ownership of shared resources via file descriptors.
+ *
+ * The caller is responsibe for doing any fencing.
+ *
+ * The