dma-buf is designed to share buffers. Sharing means that there needs to be another subsystem to accept those buffers. Introduce a simple test module to act as a dummy system to accept dma_bufs from elsewhere. The goal is to provide a very simple interface to validate exported buffers do something reasonable. This is based on ion_test.c that existed for the Ion framework.
Signed-off-by: Laura Abbott labbott@redhat.com --- This is basically a drop in of what was available as drivers/staging/android/ion/ion_test.c. Given it has no Ion specific parts it might be useful as a more general test module. RFC mostly to see if this is generally useful or not. --- drivers/dma-buf/Kconfig | 9 ++ drivers/dma-buf/Makefile | 1 + drivers/dma-buf/dma-buf-test.c | 309 ++++++++++++++++++++++++++++++++++++++ include/uapi/linux/dma_buf_test.h | 67 +++++++++ 4 files changed, 386 insertions(+) create mode 100644 drivers/dma-buf/dma-buf-test.c create mode 100644 include/uapi/linux/dma_buf_test.h
diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig index ed3b785..8b3fdb1 100644 --- a/drivers/dma-buf/Kconfig +++ b/drivers/dma-buf/Kconfig @@ -30,4 +30,13 @@ config SW_SYNC WARNING: improper use of this can result in deadlocking kernel drivers from userspace. Intended for test and debug only.
+config DMA_BUF_TEST + bool "Test module for dma-buf" + default n + ---help--- + A test module to validate dma_buf APIs. This should not be + enabled for general use. + + Say N here unless you know you want this. + endmenu diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile index c33bf88..5029608 100644 --- a/drivers/dma-buf/Makefile +++ b/drivers/dma-buf/Makefile @@ -1,3 +1,4 @@ obj-y := dma-buf.o dma-fence.o dma-fence-array.o reservation.o seqno-fence.o obj-$(CONFIG_SYNC_FILE) += sync_file.o obj-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o +obj-$(CONFIG_DMA_BUF_TEST) += dma-buf-test.o diff --git a/drivers/dma-buf/dma-buf-test.c b/drivers/dma-buf/dma-buf-test.c new file mode 100644 index 0000000..3af131c --- /dev/null +++ b/drivers/dma-buf/dma-buf-test.c @@ -0,0 +1,309 @@ +/* + * Copyright (C) 2013 Google, Inc. + * + * This software is licensed under the terms of the GNU General Public + * License versdma_buf 2, as published by the Free Software Foundatdma_buf, 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. + * + */ + +#define pr_fmt(fmt) "dma-buf-test: " fmt + +#include <linux/dma-buf.h> +#include <linux/dma-direction.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/vmalloc.h> + +#include <uapi/linux/dma_buf_test.h> + +struct dma_buf_test_device { + struct miscdevice misc; +}; + +struct dma_buf_test_data { + struct dma_buf *dma_buf; + struct device *dev; +}; + +static int dma_buf_handle_test_dma(struct device *dev, struct dma_buf *dma_buf, + void __user *ptr, size_t offset, size_t size, + bool write) +{ + int ret = 0; + struct dma_buf_attachment *attach; + struct sg_table *table; + pgprot_t pgprot = pgprot_writecombine(PAGE_KERNEL); + enum dma_data_direction dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE; + struct sg_page_iter sg_iter; + unsigned long offset_page; + + attach = dma_buf_attach(dma_buf, dev); + if (IS_ERR(attach)) + return PTR_ERR(attach); + + table = dma_buf_map_attachment(attach, dir); + if (IS_ERR(table)) + return PTR_ERR(table); + + offset_page = offset >> PAGE_SHIFT; + offset %= PAGE_SIZE; + + for_each_sg_page(table->sgl, &sg_iter, table->nents, offset_page) { + struct page *page = sg_page_iter_page(&sg_iter); + void *vaddr = vmap(&page, 1, VM_MAP, pgprot); + size_t to_copy = PAGE_SIZE - offset; + + to_copy = min(to_copy, size); + if (!vaddr) { + ret = -ENOMEM; + goto err; + } + + if (write) + ret = copy_from_user(vaddr + offset, ptr, to_copy); + else + ret = copy_to_user(ptr, vaddr + offset, to_copy); + + vunmap(vaddr); + if (ret) { + ret = -EFAULT; + goto err; + } + size -= to_copy; + if (!size) + break; + ptr += to_copy; + offset = 0; + } + +err: + dma_buf_unmap_attachment(attach, table, dir); + dma_buf_detach(dma_buf, attach); + return ret; +} + +static int dma_buf_handle_test_kernel(struct dma_buf *dma_buf, void __user *ptr, + size_t offset, size_t size, bool write) +{ + int ret; + unsigned long page_offset = offset >> PAGE_SHIFT; + size_t copy_offset = offset % PAGE_SIZE; + size_t copy_size = size; + enum dma_data_direction dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE; + + if (offset > dma_buf->size || size > dma_buf->size - offset) + return -EINVAL; + + ret = dma_buf_begin_cpu_access(dma_buf, dir); + if (ret) + return ret; + + while (copy_size > 0) { + size_t to_copy; + void *vaddr = dma_buf_kmap(dma_buf, page_offset); + + if (!vaddr) + goto err; + + to_copy = min_t(size_t, PAGE_SIZE - copy_offset, copy_size); + + if (write) + ret = copy_from_user(vaddr + copy_offset, ptr, to_copy); + else + ret = copy_to_user(ptr, vaddr + copy_offset, to_copy); + + dma_buf_kunmap(dma_buf, page_offset, vaddr); + if (ret) { + ret = -EFAULT; + goto err; + } + + copy_size -= to_copy; + ptr += to_copy; + page_offset++; + copy_offset = 0; + } +err: + dma_buf_end_cpu_access(dma_buf, dir); + return ret; +} + +static long dma_buf_test_ioctl(struct file *filp, unsigned int cmd, + unsigned long arg) +{ + struct dma_buf_test_data *test_data = filp->private_data; + int ret = 0; + + union { + struct dma_buf_test_rw_data test_rw; + } data; + + if (_IOC_SIZE(cmd) > sizeof(data)) + return -EINVAL; + + if (_IOC_DIR(cmd) & _IOC_WRITE) + if (copy_from_user(&data, (void __user *)arg, _IOC_SIZE(cmd))) + return -EFAULT; + + switch (cmd) { + case DMA_BUF_IOC_TEST_SET_FD: + { + struct dma_buf *dma_buf = NULL; + int fd = arg; + + if (fd >= 0) { + dma_buf = dma_buf_get((int)arg); + if (IS_ERR(dma_buf)) + return PTR_ERR(dma_buf); + } + if (test_data->dma_buf) + dma_buf_put(test_data->dma_buf); + test_data->dma_buf = dma_buf; + break; + } + case DMA_BUF_IOC_TEST_DMA_MAPPING: + { + ret = dma_buf_handle_test_dma(test_data->dev, + test_data->dma_buf, + u64_to_user_ptr(data.test_rw.ptr), + data.test_rw.offset, + data.test_rw.size, + data.test_rw.write); + break; + } + case DMA_BUF_IOC_TEST_KERNEL_MAPPING: + { + ret = dma_buf_handle_test_kernel(test_data->dma_buf, + u64_to_user_ptr(data.test_rw.ptr), + data.test_rw.offset, + data.test_rw.size, + data.test_rw.write); + break; + } + default: + return -ENOTTY; + } + + if (_IOC_DIR(cmd) & _IOC_READ) { + if (copy_to_user((void __user *)arg, &data, sizeof(data))) + return -EFAULT; + } + return ret; +} + +static int dma_buf_test_open(struct inode *inode, struct file *file) +{ + struct dma_buf_test_data *data; + struct miscdevice *miscdev = file->private_data; + + data = kzalloc(sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->dev = miscdev->parent; + + file->private_data = data; + + return 0; +} + +static int dma_buf_test_release(struct inode *inode, struct file *file) +{ + struct dma_buf_test_data *data = file->private_data; + + kfree(data); + + return 0; +} + +static const struct file_operations dma_buf_test_fops = { + .owner = THIS_MODULE, + .unlocked_ioctl = dma_buf_test_ioctl, + .compat_ioctl = dma_buf_test_ioctl, + .open = dma_buf_test_open, + .release = dma_buf_test_release, +}; + +static int __init dma_buf_test_probe(struct platform_device *pdev) +{ + int ret; + struct dma_buf_test_device *testdev; + + testdev = devm_kzalloc(&pdev->dev, sizeof(struct dma_buf_test_device), + GFP_KERNEL); + if (!testdev) + return -ENOMEM; + + testdev->misc.minor = MISC_DYNAMIC_MINOR; + testdev->misc.name = "dma_buf-test"; + testdev->misc.fops = &dma_buf_test_fops; + testdev->misc.parent = &pdev->dev; + /* + * We need to force 'something' for a DMA mask. This isn't an actual + * device and won't be doing actual DMA so pick 'something' that + * probably won't blow up. Probably. + */ + dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64)); + ret = misc_register(&testdev->misc); + if (ret) { + pr_err("failed to register misc device.\n"); + return ret; + } + + platform_set_drvdata(pdev, testdev); + + return 0; +} + +static int dma_buf_test_remove(struct platform_device *pdev) +{ + struct dma_buf_test_device *testdev; + + testdev = platform_get_drvdata(pdev); + if (!testdev) + return -ENODATA; + + misc_deregister(&testdev->misc); + return 0; +} + +static struct platform_device *dma_buf_test_pdev; +static struct platform_driver dma_buf_test_platform_driver = { + .remove = dma_buf_test_remove, + .driver = { + .name = "dma_buf-test", + }, +}; + +static int __init dma_buf_test_init(void) +{ + dma_buf_test_pdev = platform_device_register_simple("dma-buf-test", + -1, NULL, 0); + if (IS_ERR(dma_buf_test_pdev)) + return PTR_ERR(dma_buf_test_pdev); + + return platform_driver_probe(&dma_buf_test_platform_driver, + dma_buf_test_probe); +} + +static void __exit dma_buf_test_exit(void) +{ + platform_driver_unregister(&dma_buf_test_platform_driver); + platform_device_unregister(dma_buf_test_pdev); +} + +module_init(dma_buf_test_init); +module_exit(dma_buf_test_exit); +MODULE_LICENSE("GPL v2"); diff --git a/include/uapi/linux/dma_buf_test.h b/include/uapi/linux/dma_buf_test.h new file mode 100644 index 0000000..af2d521 --- /dev/null +++ b/include/uapi/linux/dma_buf_test.h @@ -0,0 +1,67 @@ +/* + * Copyright (C) 2011 Google, Inc. + * + * This software is licensed under the terms of the GNU General Public + * License versdma_buf 2, as published by the Free Software Foundatdma_buf, 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_DMA_BUF_TEST_H +#define _UAPI_LINUX_DMA_BUF_TEST_H + +#include <linux/ioctl.h> +#include <linux/types.h> + +/** + * struct dma_buf_test_rw_data - metadata passed to the kernel to read handle + * @ptr: a pointer to an area at least as large as size + * @offset: offset into the dma_buf buffer to start reading + * @size: size to read or write + * @write: 1 to write, 0 to read + */ +struct dma_buf_test_rw_data { + __u64 ptr; + __u64 offset; + __u64 size; + int write; + int __padding; +}; + +#define DMA_BUF_IOC_MAGIC 'I' + +/** + * DOC: DMA_BUF_IOC_TEST_SET_DMA_BUF - attach a dma buf to the test driver + * + * Attaches a dma buf fd to the test driver. Passing a second fd or -1 will + * release the first fd. + */ +#define DMA_BUF_IOC_TEST_SET_FD \ + _IO(DMA_BUF_IOC_MAGIC, 0xf0) + +/** + * DOC: DMA_BUF_IOC_TEST_DMA_MAPPING - read or write memory from a handle as DMA + * + * Reads or writes the memory from a handle using an uncached mapping. Can be + * used by unit tests to emulate a DMA engine as close as possible. Only + * expected to be used for debugging and testing, may not always be available. + */ +#define DMA_BUF_IOC_TEST_DMA_MAPPING \ + _IOW(DMA_BUF_IOC_MAGIC, 0xf1, struct dma_buf_test_rw_data) + +/** + * DOC: DMA_BUF_IOC_TEST_KERNEL_MAPPING - read or write memory from a handle + * + * Reads or writes the memory from a handle using a kernel mapping. Can be + * used by unit tests to test heap map_kernel functdma_bufs. Only expected to be + * used for debugging and testing, may not always be available. + */ +#define DMA_BUF_IOC_TEST_KERNEL_MAPPING \ + _IOW(DMA_BUF_IOC_MAGIC, 0xf2, struct dma_buf_test_rw_data) + +#endif /* _UAPI_LINUX_DMA_BUF_TEST_H */