Date:   Wed, 6 Mar 2019 10:35:27 -0600
From:   "Andrew F. Davis" <afd@...com>
To:     Benjamin Gaignard <benjamin.gaignard@...aro.org>,
        John Stultz <john.stultz@...aro.org>
CC:     lkml <linux-kernel@...r.kernel.org>,
        Laura Abbott <labbott@...hat.com>,
        Greg KH <gregkh@...uxfoundation.org>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Liam Mark <lmark@...eaurora.org>,
        Brian Starkey <Brian.Starkey@....com>,
        Chenbo Feng <fengc@...gle.com>,
        Alistair Strachan <astrachan@...gle.com>,
        ML dri-devel <dri-devel@...ts.freedesktop.org>
Subject: Re: [RFC][PATCH 5/5 v2] kselftests: Add dma-heap test

On 3/6/19 10:14 AM, Benjamin Gaignard wrote:
> Le mar. 5 mars 2019 à 21:54, John Stultz <john.stultz@...aro.org> a écrit :
>>
>> Add very trivial allocation test for dma-heaps.
>>
>> TODO: Need to actually do some validation on
>> the returned dma-buf.
>>
>> Cc: Laura Abbott <labbott@...hat.com>
>> Cc: Benjamin Gaignard <benjamin.gaignard@...aro.org>
>> Cc: Greg KH <gregkh@...uxfoundation.org>
>> Cc: Sumit Semwal <sumit.semwal@...aro.org>
>> Cc: Liam Mark <lmark@...eaurora.org>
>> Cc: Brian Starkey <Brian.Starkey@....com>
>> Cc: Andrew F. Davis <afd@...com>
>> Cc: Chenbo Feng <fengc@...gle.com>
>> Cc: Alistair Strachan <astrachan@...gle.com>
>> Cc: dri-devel@...ts.freedesktop.org
>> Signed-off-by: John Stultz <john.stultz@...aro.org>
>> ---
>> v2: Switched to use reworked dma-heap apis
>> ---
>>  tools/testing/selftests/dmabuf-heaps/Makefile      | 11 +++
>>  tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c | 96 ++++++++++++++++++++++
>>  2 files changed, 107 insertions(+)
>>  create mode 100644 tools/testing/selftests/dmabuf-heaps/Makefile
>>  create mode 100644 tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
>>
>> diff --git a/tools/testing/selftests/dmabuf-heaps/Makefile b/tools/testing/selftests/dmabuf-heaps/Makefile
>> new file mode 100644
>> index 0000000..c414ad3
>> --- /dev/null
>> +++ b/tools/testing/selftests/dmabuf-heaps/Makefile
>> @@ -0,0 +1,11 @@
>> +# SPDX-License-Identifier: GPL-2.0
>> +CFLAGS += -static -O3 -Wl,-no-as-needed -Wall
>> +#LDLIBS += -lrt -lpthread -lm
>> +
>> +# these are all "safe" tests that don't modify
>> +# system time or require escalated privileges
>> +TEST_GEN_PROGS = dmabuf-heap
>> +
>> +
>> +include ../lib.mk
>> +
>> diff --git a/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c b/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
>> new file mode 100644
>> index 0000000..06837a4
>> --- /dev/null
>> +++ b/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
>> @@ -0,0 +1,96 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +
>> +#include <dirent.h>
>> +#include <errno.h>
>> +#include <fcntl.h>
>> +#include <stdio.h>
>> +#include <string.h>
>> +#include <unistd.h>
>> +#include <sys/ioctl.h>
>> +#include <sys/mman.h>
>> +#include <sys/types.h>
>> +
>> +#include "../../../../include/uapi/linux/dma-heap.h"
>> +
>> +#define DEVPATH "/dev/dma_heap"
>> +
>> +int dmabuf_heap_open(char *name)
>> +{
>> +       int ret, fd;
>> +       char buf[256];
>> +
>> +       ret = sprintf(buf, "%s/%s", DEVPATH, name);
>> +       if (ret < 0) {
>> +               printf("sprintf failed!\n");
>> +               return ret;
>> +       }
>> +
>> +       fd = open(buf, O_RDWR);
>> +       if (fd < 0)
>> +               printf("open %s failed!\n", buf);
>> +       return fd;
>> +}
>> +
>> +int dmabuf_heap_alloc(int fd, size_t len, unsigned int flags, int *dmabuf_fd)
>> +{
>> +       struct dma_heap_allocation_data data = {
>> +               .len = len,
>> +               .flags = flags,
>> +       };
>> +       int ret;
>> +
>> +       if (dmabuf_fd == NULL)
>> +               return -EINVAL;
>> +
>> +       ret = ioctl(fd, DMA_HEAP_IOC_ALLOC, &data);
>> +       if (ret < 0)
>> +               return ret;
>> +       *dmabuf_fd = (int)data.fd;
>> +       return ret;
>> +}
>> +
>> +#define ONE_MEG (1024*1024)
>> +
>> +void do_test(char *heap_name)
>> +{
>> +       int heap_fd = -1, dmabuf_fd = -1;
>> +       int ret;
>> +
>> +       printf("Testing heap: %s\n", heap_name);
>> +
>> +       heap_fd = dmabuf_heap_open(heap_name);
>> +       if (heap_fd < 0)
>> +               return;
>> +
>> +       printf("Allocating 1 MEG\n");
>> +       ret = dmabuf_heap_alloc(heap_fd, ONE_MEG, 0, &dmabuf_fd);
>> +       if (ret)
>> +               goto out;
>> +
>> +       /* DO SOMETHING WITH THE DMABUF HERE? */
> 
> You can do a call to mmap and write a pattern in the buffer.
> 

mmap is optional for DMA-BUFs, only attach/map are required. To test
those we would need a dummy device, so a test kernel module may be
needed to really exercise this.

I have one I use for ION buffer testing, it consumes a DMA-BUF passed
from userspace, attach/maps it to a dummy device then return the
physical address of the first page of the buffer for validation. Might
be a good test, but dummy devices don't always have the proper dma
attributes set like a real device does, so it may also fail for some
otherwise valid buffers.

Andrew

> Benjamin
>> +
>> +out:
>> +       if (dmabuf_fd >= 0)
>> +               close(dmabuf_fd);
>> +       if (heap_fd >= 0)
>> +               close(heap_fd);
>> +}
>> +
>> +
>> +int main(void)
>> +{
>> +       DIR *d;
>> +       struct dirent *dir;
>> +
>> +       d = opendir(DEVPATH);
>> +       if (!d) {
>> +               printf("No %s directory?\n", DEVPATH);
>> +               return -1;
>> +       }
>> +
>> +       while ((dir = readdir(d)) != NULL)
>> +               do_test(dir->d_name);
>> +
>> +
>> +       return 0;
>> +}
>> --
>> 2.7.4
>>
> 
> 

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