linux-kernel - Re: [RFC][PATCH 5/5 v2] kselftests: Add dma-heap test

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Message-ID: <CALAqxLU9aq6Qj1qJKQK=a5AbnLc1Hwxvb0nX9JemoW=29gDVoA@mail.gmail.com>
Date:   Wed, 6 Mar 2019 10:19:36 -0800
From:   John Stultz <john.stultz@...aro.org>
To:     "Andrew F. Davis" <afd@...com>
Cc:     Benjamin Gaignard <benjamin.gaignard@...aro.org>,
        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 Wed, Mar 6, 2019 at 10:15 AM Andrew F. Davis <afd@...com> wrote:
>
> 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.

Cool! Do you mind sharing that? I might try to rework and integrate it
into this patchset?

thanks
-john