@@ -200,4 +200,22 @@ config SYNC
This option enables the framework for synchronization between multiple
drivers. Sync implementations can take advantage of hardware
synchronization built into devices like GPUs.
+
+config SW_SYNC
+ bool "Software synchronization objects"
+ default n
+ depends on SYNC
+ help
+ A sync object driver that uses a 32bit counter to coordinate
+ syncrhronization. Useful when there is no hardware primitive backing
+ the synchronization.
+
+config SW_SYNC_USER
+ bool "Userspace API for SW_SYNC"
+ default n
+ depends on SW_SYNC
+ help
+ Provides a user space API to the sw sync object.
+ *WARNING* improper use of this can result in deadlocking kernel
+ drivers from userspace.
endmenu
@@ -22,6 +22,7 @@ obj-$(CONFIG_REGMAP) += regmap/
obj-$(CONFIG_SOC_BUS) += soc.o
obj-$(CONFIG_SYNC) += sync.o
+obj-$(CONFIG_SW_SYNC) += sw_sync.o
ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
new file mode 100644
@@ -0,0 +1,223 @@
+/*
+ * drivers/base/sw_sync.c
+ *
+ * Copyright (C) 2012 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.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/sw_sync.h>
+#include <linux/syscalls.h>
+#include <linux/uaccess.h>
+
+static int sw_sync_cmp(u32 a, u32 b)
+{
+ if (a == b)
+ return 0;
+
+ return ((s32)a - (s32)b) < 0 ? -1 : 1;
+}
+
+struct sync_pt *sw_sync_pt_create(struct sw_sync_timeline *obj, u32 value)
+{
+ struct sw_sync_pt *pt;
+
+ pt = (struct sw_sync_pt *)
+ sync_pt_create(&obj->obj, sizeof(struct sw_sync_pt));
+
+ pt->value = value;
+
+ return (struct sync_pt *)pt;
+}
+
+static struct sync_pt *sw_sync_pt_dup(struct sync_pt *sync_pt)
+{
+ struct sw_sync_pt *pt = (struct sw_sync_pt *) sync_pt;
+ struct sw_sync_timeline *obj =
+ (struct sw_sync_timeline *)sync_pt->parent;
+
+ return (struct sync_pt *) sw_sync_pt_create(obj, pt->value);
+}
+
+static int sw_sync_pt_has_signaled(struct sync_pt *sync_pt)
+{
+ struct sw_sync_pt *pt = (struct sw_sync_pt *)sync_pt;
+ struct sw_sync_timeline *obj =
+ (struct sw_sync_timeline *)sync_pt->parent;
+
+ return sw_sync_cmp(obj->value, pt->value) >= 0;
+}
+
+static int sw_sync_pt_compare(struct sync_pt *a, struct sync_pt *b)
+{
+ struct sw_sync_pt *pt_a = (struct sw_sync_pt *)a;
+ struct sw_sync_pt *pt_b = (struct sw_sync_pt *)b;
+
+ return sw_sync_cmp(pt_a->value, pt_b->value);
+}
+
+struct sync_timeline_ops sw_sync_timeline_ops = {
+ .driver_name = "sw_sync",
+ .dup = sw_sync_pt_dup,
+ .has_signaled = sw_sync_pt_has_signaled,
+ .compare = sw_sync_pt_compare,
+};
+
+
+struct sw_sync_timeline *sw_sync_timeline_create(const char *name)
+{
+ struct sw_sync_timeline *obj = (struct sw_sync_timeline *)
+ sync_timeline_create(&sw_sync_timeline_ops,
+ sizeof(struct sw_sync_timeline),
+ name);
+
+ return obj;
+}
+
+void sw_sync_timeline_inc(struct sw_sync_timeline *obj, u32 inc)
+{
+ obj->value += inc;
+
+ sync_timeline_signal(&obj->obj);
+}
+
+
+#ifdef CONFIG_SW_SYNC_USER
+/* *WARNING*
+ *
+ * improper use of this can result in deadlocking kernel drivers from userspace.
+ */
+
+/* opening sw_sync create a new sync obj */
+int sw_sync_open(struct inode *inode, struct file *file)
+{
+ struct sw_sync_timeline *obj;
+ char task_comm[TASK_COMM_LEN];
+
+ get_task_comm(task_comm, current);
+
+ obj = sw_sync_timeline_create(task_comm);
+ if (obj == NULL)
+ return -ENOMEM;
+
+ file->private_data = obj;
+
+ return 0;
+}
+
+int sw_sync_release(struct inode *inode, struct file *file)
+{
+ struct sw_sync_timeline *obj = file->private_data;
+ sync_timeline_destroy(&obj->obj);
+ return 0;
+}
+
+long sw_sync_ioctl_create_fence(struct sw_sync_timeline *obj, unsigned long arg)
+{
+ int fd = get_unused_fd();
+ int err;
+ struct sync_pt *pt;
+ struct sync_fence *fence;
+ struct sw_sync_create_fence_data data;
+
+ if (copy_from_user(&data, (void __user *)arg, sizeof(data)))
+ return -EFAULT;
+
+ pt = sw_sync_pt_create(obj, data.value);
+ if (pt == NULL) {
+ err = -ENOMEM;
+ goto err;
+ }
+
+ data.name[sizeof(data.name) - 1] = '\0';
+ fence = sync_fence_create(data.name, pt);
+ if (fence == NULL) {
+ sync_pt_free(pt);
+ err = -ENOMEM;
+ goto err;
+ }
+
+ data.fence = fd;
+ if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
+ sync_fence_put(fence);
+ err = -EFAULT;
+ goto err;
+ }
+
+ sync_fence_install(fence, fd);
+
+ return 0;
+
+err:
+ put_unused_fd(fd);
+ return err;
+}
+
+long sw_sync_ioctl_inc(struct sw_sync_timeline *obj, unsigned long arg)
+{
+ u32 value;
+
+ if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
+ return -EFAULT;
+
+ sw_sync_timeline_inc(obj, value);
+
+ return 0;
+}
+
+long sw_sync_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct sw_sync_timeline *obj = file->private_data;
+
+ switch (cmd) {
+ case SW_SYNC_IOC_CREATE_FENCE:
+ return sw_sync_ioctl_create_fence(obj, arg);
+
+ case SW_SYNC_IOC_INC:
+ return sw_sync_ioctl_inc(obj, arg);
+
+ default:
+ return -ENOTTY;
+ }
+}
+
+static const struct file_operations sw_sync_fops = {
+ .owner = THIS_MODULE,
+ .open = sw_sync_open,
+ .release = sw_sync_release,
+ .unlocked_ioctl = sw_sync_ioctl,
+};
+
+static struct miscdevice sw_sync_dev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "sw_sync",
+ .fops = &sw_sync_fops,
+};
+
+int __init sw_sync_device_init(void)
+{
+ return misc_register(&sw_sync_dev);
+}
+
+void __exit sw_sync_device_remove(void)
+{
+ misc_deregister(&sw_sync_dev);
+}
+
+module_init(sw_sync_device_init);
+module_exit(sw_sync_device_remove);
+
+#endif /* CONFIG_SW_SYNC_USER */
new file mode 100644
@@ -0,0 +1,58 @@
+/*
+ * include/linux/sw_sync.h
+ *
+ * Copyright (C) 2012 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 _LINUX_SW_SYNC_H
+#define _LINUX_SW_SYNC_H
+
+#include <linux/types.h>
+
+#ifdef __KERNEL__
+
+#include <linux/sync.h>
+
+struct sw_sync_timeline {
+ struct sync_timeline obj;
+
+ u32 value;
+};
+
+struct sw_sync_pt {
+ struct sync_pt pt;
+
+ u32 value;
+};
+
+struct sw_sync_timeline *sw_sync_timeline_create(const char *name);
+void sw_sync_timeline_inc(struct sw_sync_timeline *obj, u32 inc);
+
+struct sync_pt *sw_sync_pt_create(struct sw_sync_timeline *obj, u32 value);
+
+#endif /* __KERNEL __ */
+
+struct sw_sync_create_fence_data {
+ __u32 value;
+ char name[32];
+ __s32 fence; /* fd of new fence */
+};
+
+#define SW_SYNC_IOC_MAGIC 'W'
+
+#define SW_SYNC_IOC_CREATE_FENCE _IOWR(SW_SYNC_IOC_MAGIC, 0,\
+ struct sw_sync_create_fence_data)
+#define SW_SYNC_IOC_INC _IOW(SW_SYNC_IOC_MAGIC, 1, __u32)
+
+
+#endif /* _LINUX_SW_SYNC_H */
This driver can be used by synchronization providers that don't need to communicate with hardware backed sync primitives. Signed-off-by: Erik Gilling <konkers@android.com> --- drivers/base/Kconfig | 18 ++++ drivers/base/Makefile | 1 + drivers/base/sw_sync.c | 223 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/sw_sync.h | 58 ++++++++++++ 4 files changed, 300 insertions(+), 0 deletions(-) create mode 100644 drivers/base/sw_sync.c create mode 100644 include/linux/sw_sync.h