This is the core of simple allocator module.
It aim to offert one common ioctl to allocate specific memory.
version 2:
- rebased on 4.10-rc7
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>
---
Documentation/simple-allocator.txt | 81 +++++++++++
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/simpleallocator/Kconfig | 10 ++
drivers/simpleallocator/Makefile | 1 +
drivers/simpleallocator/simple-allocator-priv.h | 33 +++++
drivers/simpleallocator/simple-allocator.c | 180 ++++++++++++++++++++++++
include/uapi/linux/simple-allocator.h | 35 +++++
8 files changed, 343 insertions(+)
create mode 100644 Documentation/simple-allocator.txt
create mode 100644 drivers/simpleallocator/Kconfig
create mode 100644 drivers/simpleallocator/Makefile
create mode 100644 drivers/simpleallocator/simple-allocator-priv.h
create mode 100644 drivers/simpleallocator/simple-allocator.c
create mode 100644 include/uapi/linux/simple-allocator.h
diff --git a/Documentation/simple-allocator.txt b/Documentation/simple-allocator.txt
new file mode 100644
index 0000000..89ba883
--- /dev/null
+++ b/Documentation/simple-allocator.txt
@@ -0,0 +1,81 @@
+Simple Allocator Framework
+
+Simple Allocator offer a single ioctl SA_IOC_ALLOC to allocate buffers
+on dedicated memory regions and export them as a dmabuf file descriptor.
+Using dmabuf file descriptor allow to share this memory between processes
+and/or import it into other frameworks like v4l2 or drm/kms (prime).
+When userland wants to free the memory only a call to close() in needed
+so it could done even without knowing that buffer has been allocated by
+simple allocator ioctl.
+
+Each memory regions will be seen as a filein /dev/.
+For example CMA regions will exposed has /dev/cmaX.
+
+Implementing a simple allocator
+-------------------------------
+
+Simple Allocator provide helpers functions to register/unregister an
+allocator:
+- simple_allocator_register(struct sa_device *sadev)
+ Register simple_allocator_device using sa_device structure where name,
+ owner and allocate fields must be set.
+
+- simple_allocator_unregister(struct sa_device *sadev)
+ Unregister a simple allocator device.
+
+Using Simple Allocator /dev interface example
+---------------------------------------------
+
+This example of code allocate a buffer on the first CMA region (/dev/cma0)
+before mmap and close it.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "simple-allocator.h"
+
+#define LENGTH 1024*16
+
+void main (void)
+{
+ struct simple_allocate_data data;
+ int fd = open("/dev/cma0", O_RDWR, 0);
+ int ret;
+ void *mem;
+
+ if (fd < 0) {
+ printf("Can't open /dev/cma0\n");
+ return;
+ }
+
+ memset(&data, 0, sizeof(data));
+
+ data.length = LENGTH;
+ data.flags = O_RDWR | O_CLOEXEC;
+
+ ret = ioctl(fd, SA_IOC_ALLOC, &data);
+ if (ret) {
+ printf("Buffer allocation failed\n");
+ goto end;
+ }
+
+ mem = mmap(0, LENGTH, PROT_READ | PROT_WRITE, MAP_SHARED, data.fd, 0);
+ if (mem == MAP_FAILED) {
+ printf("mmap failed\n");
+ }
+
+ memset(mem, 0xFF, LENGTH);
+ munmap(mem, LENGTH);
+
+ printf("test simple allocator CMA OK\n");
+end:
+ close(fd);
+}
diff --git a/drivers/Kconfig b/drivers/Kconfig
index e1e2066..a6d8828 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -202,4 +202,6 @@ source "drivers/hwtracing/intel_th/Kconfig"
source "drivers/fpga/Kconfig"
+source "drivers/simpleallocator/Kconfig"
+
endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 060026a..5081eb8 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -173,3 +173,4 @@ obj-$(CONFIG_STM) += hwtracing/stm/
obj-$(CONFIG_ANDROID) += android/
obj-$(CONFIG_NVMEM) += nvmem/
obj-$(CONFIG_FPGA) += fpga/
+obj-$(CONFIG_SIMPLE_ALLOCATOR) += simpleallocator/
diff --git a/drivers/simpleallocator/Kconfig b/drivers/simpleallocator/Kconfig
new file mode 100644
index 0000000..c6fc2e3
--- /dev/null
+++ b/drivers/simpleallocator/Kconfig
@@ -0,0 +1,10 @@
+menu "Simple Allocator"
+
+config SIMPLE_ALLOCATOR
+ tristate "Simple Alllocator Framework"
+ select DMA_SHARED_BUFFER
+ ---help---
+ The Simple Allocator Framework adds an API to allocate and share
+ memory in userland.
+
+endmenu
diff --git a/drivers/simpleallocator/Makefile b/drivers/simpleallocator/Makefile
new file mode 100644
index 0000000..e27c6ad
--- /dev/null
+++ b/drivers/simpleallocator/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_SIMPLE_ALLOCATOR) += simple-allocator.o
diff --git a/drivers/simpleallocator/simple-allocator-priv.h b/drivers/simpleallocator/simple-allocator-priv.h
new file mode 100644
index 0000000..33f5a33
--- /dev/null
+++ b/drivers/simpleallocator/simple-allocator-priv.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) Linaro 2016
+ *
+ * Author: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>
+ *
+ * License terms: GNU General Public License (GPL)
+ */
+
+#ifndef _SIMPLE_ALLOCATOR_PRIV_H_
+#define _SIMPLE_ALLOCATOR_PRIV_H_
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/dma-buf.h>
+
+/**
+ * struct sa_device - simple allocator device
+ * @owner: module owner, must be set to THIS_MODULE
+ * @name: name of the allocator
+ * @allocate: callabck for memory allocation
+ */
+struct sa_device {
+ struct device dev;
+ struct cdev chrdev;
+ struct module *owner;
+ const char *name;
+ struct dma_buf *(*allocate)(struct sa_device *, u64 length, u32 flags);
+};
+
+int simple_allocator_register(struct sa_device *sadev);
+void simple_allocator_unregister(struct sa_device *sadev);
+
+#endif
diff --git a/drivers/simpleallocator/simple-allocator.c b/drivers/simpleallocator/simple-allocator.c
new file mode 100644
index 0000000..d89ccbf
--- /dev/null
+++ b/drivers/simpleallocator/simple-allocator.c
@@ -0,0 +1,180 @@
+/*
+ * Copyright (C) Linaro 2016
+ *
+ * Author: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>
+ *
+ * License terms: GNU General Public License (GPL)
+ */
+
+#include <linux/module.h>
+#include <linux/simple-allocator.h>
+#include <linux/uaccess.h>
+
+#include "simple-allocator-priv.h"
+
+#define SA_MAJOR 222
+#define SA_NUM_DEVICES 256
+#define SA_NAME "simple_allocator"
+
+static int sa_minor;
+
+static struct class sa_class = {
+ .name = SA_NAME,
+};
+
+static long sa_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+ struct sa_device *sadev = filp->private_data;
+ int ret = -ENODEV;
+
+ switch (cmd) {
+ case SA_IOC_ALLOC:
+ {
+ struct simple_allocate_data data;
+ struct dma_buf *dmabuf;
+
+ if (copy_from_user(&data, (void __user *)arg, _IOC_SIZE(cmd)))
+ return -EFAULT;
+
+ if (data.version != 0)
+ return -EINVAL;
+
+ dmabuf = sadev->allocate(sadev, data.length, data.flags);
+ if (!dmabuf)
+ return -EINVAL;
+
+ data.fd = dma_buf_fd(dmabuf, data.flags);
+ if (data.fd < 0) {
+ dma_buf_put(dmabuf);
+ return -EINVAL;
+ }
+
+ data.length = dmabuf->size;
+
+ if (copy_to_user((void __user *)arg, &data, _IOC_SIZE(cmd))) {
+ dma_buf_put(dmabuf);
+ return -EFAULT;
+ }
+
+ return 0;
+ }
+ }
+ return ret;
+}
+
+static int sa_open(struct inode *inode, struct file *filp)
+{
+ struct sa_device *sadev = container_of(inode->i_cdev,
+ struct sa_device, chrdev);
+
+ if (!sadev)
+ return -ENODEV;
+
+ get_device(&sadev->dev);
+ filp->private_data = sadev;
+ return 0;
+}
+
+static int sa_release(struct inode *inode, struct file *filp)
+{
+ struct sa_device *sadev = container_of(inode->i_cdev,
+ struct sa_device, chrdev);
+
+ if (!sadev)
+ return -ENODEV;
+
+ put_device(&sadev->dev);
+ return 0;
+}
+
+static const struct file_operations sa_fops = {
+ .owner = THIS_MODULE,
+ .open = sa_open,
+ .release = sa_release,
+ .unlocked_ioctl = sa_ioctl,
+};
+
+/**
+ * simple_allocator_register - register a simple allocator
+ * @sadev: simple allocator structure to be registered
+ *
+ * Return 0 if allocator has been regsitered, either a negative value.
+ */
+int simple_allocator_register(struct sa_device *sadev)
+{
+ int ret;
+
+ if (!sadev->name || !sadev->allocate)
+ return -EINVAL;
+
+ cdev_init(&sadev->chrdev, &sa_fops);
+ sadev->chrdev.owner = sadev->owner;
+
+ ret = cdev_add(&sadev->chrdev, MKDEV(SA_MAJOR, sa_minor), 1);
+ if (ret < 0)
+ return ret;
+
+ sadev->dev.class = &sa_class;
+ sadev->dev.devt = MKDEV(SA_MAJOR, sa_minor);
+ dev_set_name(&sadev->dev, "%s%d", sadev->name, sa_minor);
+ ret = device_register(&sadev->dev);
+ if (ret < 0)
+ goto cleanup;
+
+ sa_minor++;
+ return 0;
+
+cleanup:
+ cdev_del(&sadev->chrdev);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(simple_allocator_register);
+
+/**
+ * simple_allocator_unregister - unregister a simple allocator
+ * @sadev: simple allocator device to be unregistered
+ */
+void simple_allocator_unregister(struct sa_device *sadev)
+{
+ if (!sadev)
+ return;
+
+ cdev_del(&sadev->chrdev);
+ device_del(&sadev->dev);
+ put_device(&sadev->dev);
+}
+EXPORT_SYMBOL_GPL(simple_allocator_unregister);
+
+static int __init sa_init(void)
+{
+ dev_t dev = MKDEV(SA_MAJOR, 0);
+ int ret;
+
+ ret = register_chrdev_region(dev, SA_NUM_DEVICES, SA_NAME);
+ if (ret < 0)
+ return ret;
+
+ ret = class_register(&sa_class);
+ if (ret < 0) {
+ unregister_chrdev_region(dev, SA_NUM_DEVICES);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static void __exit sa_exit(void)
+{
+ dev_t dev = MKDEV(SA_MAJOR, 0);
+
+ class_unregister(&sa_class);
+ unregister_chrdev_region(dev, SA_NUM_DEVICES);
+}
+
+subsys_initcall(sa_init);
+module_exit(sa_exit);
+
+MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Simple allocator");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_CHARDEV_MAJOR(SA_MAJOR);
diff --git a/include/uapi/linux/simple-allocator.h b/include/uapi/linux/simple-allocator.h
new file mode 100644
index 0000000..5520a85
--- /dev/null
+++ b/include/uapi/linux/simple-allocator.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) Linaro 2016
+ *
+ * Author: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>
+ *
+ * License terms: GNU General Public License (GPL), version 2
+ */
+
+#ifndef _SIMPLE_ALLOCATOR_H_
+#define _SIMPLE_ALLOCATOR_H_
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+/**
+ * struct simple_allocate_data - allocation parameters
+ * @version: structure version (must be set to 0)
+ * @length: size of the requested buffer
+ * @flags: mode flags for the file like O_RDWR or O_CLOEXEC
+ * @fd: returned file descriptor
+ */
+struct simple_allocate_data {
+ __u64 version;
+ __u64 length;
+ __u32 flags;
+ __u32 reserved1;
+ __s32 fd;
+ __u32 reserved2;
+};
+
+#define SA_IOC_MAGIC 'S'
+
+#define SA_IOC_ALLOC _IOWR(SA_IOC_MAGIC, 0, struct simple_allocate_data)
+
+#endif
--
1.9.1
