For the record.
On 2017-12-13 01:26 PM, Christian König wrote:
> Actually we try to avoid that drivers define their own dma_buf_ops in DRM.
>
> That's why you have all those callbacks in drm_driver which just mirror the
> dma_buf interface but unpack the GEM object from the dma-buf object.
>
> There are quite a number of exceptions, but those drivers then implement
> everything on their own because the DRM marshaling doesn't make sense for
> them.
>
> Christian.
>
> Am 13.12.2017 um 19:01 schrieb Samuel Li:
>> That is an approach. The cost is to add a new call back, which is not
>> necessary though, since driver can always actually define their own
>> dma_buf_ops.
>> The intention here is to allow a driver reuse drm_gem_prime_dmabuf_ops{}. If
>> you would like to go this far, maybe a more straight forward way is to
>> export those ops, e.g. drm_gem_map_attach, so that a driver can use them in
>> its own definitions.
>>
>> Sam
>>
>>
>>
>> On 2017-12-13 05:23 AM, Christian König wrote:
>>> Something like the attached patch. Not even compile tested.
>>>
>>> Christian.
>>>
>>> Am 12.12.2017 um 20:13 schrieb Samuel Li:
>>>> Not sure if I understand your comments correctly. Currently amdgpu prime
>>>> reuses drm_gem_prime_dmabuf_ops{}, and it is defined as static which is
>>>> reasonable. I do not see an easier way to introduce
>>>> amdgpu_gem_begin_cpu_access().
>>>>
>>>> Sam
>>>>
>>>> On 2017-12-12 01:30 PM, Christian König wrote:
>>>>>> + while (amdgpu_dmabuf_ops.begin_cpu_access !=
>>>>>> amdgpu_gem_begin_cpu_access)
>>>>> I would rather just add the four liner code to drm to forward the
>>>>> begin_cpu_access callback into a drm_driver callback instead of all this.
>>>>>
>>>>> But apart from that it looks good to me.
>>>>>
>>>>> Christian.
>>>>>
>>>>> Am 12.12.2017 um 19:14 schrieb Li, Samuel:
>>>>>> A gentle ping on this one, Christian, can you take a look at this?
>>>>>>
>>>>>> Sam
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Li, Samuel
>>>>>> Sent: Friday, December 08, 2017 5:22 PM
>>>>>> To: [email protected]
>>>>>> Cc: Li, Samuel <[email protected]>
>>>>>> Subject: [PATCH v2 2/2] drm/amdgpu: Move to gtt before cpu accesses dma
>>>>>> buf.
>>>>>>
>>>>>> To improve cpu read performance. This is implemented for APUs currently.
>>>>>>
>>>>>> v2: Adapt to change
>>>>>> https://lists.freedesktop.org/archives/amd-gfx/2017-October/015174.html
>>>>>>
>>>>>> Change-Id: I7a583e23a9ee706e0edd2a46f4e4186a609368e3
>>>>>> ---
>>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu.h | 2 ++
>>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 2 +-
>>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c | 58
>>>>>> +++++++++++++++++++++++++++++++
>>>>>> 3 files changed, 61 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>>> index f8657c3..193db70 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>>> @@ -417,6 +417,8 @@ amdgpu_gem_prime_import_sg_table(struct drm_device
>>>>>> *dev, struct dma_buf *amdgpu_gem_prime_export(struct drm_device *dev,
>>>>>> struct drm_gem_object *gobj,
>>>>>> int flags);
>>>>>> +struct drm_gem_object *amdgpu_gem_prime_import(struct drm_device *dev,
>>>>>> + struct dma_buf *dma_buf);
>>>>>> int amdgpu_gem_prime_pin(struct drm_gem_object *obj); void
>>>>>> amdgpu_gem_prime_unpin(struct drm_gem_object *obj); struct
>>>>>> reservation_object *amdgpu_gem_prime_res_obj(struct drm_gem_object *);
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>>>>> index 31383e0..df30b08 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>>>>> @@ -868,7 +868,7 @@ static struct drm_driver kms_driver = {
>>>>>> .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
>>>>>> .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
>>>>>> .gem_prime_export = amdgpu_gem_prime_export,
>>>>>> - .gem_prime_import = drm_gem_prime_import,
>>>>>> + .gem_prime_import = amdgpu_gem_prime_import,
>>>>>> .gem_prime_pin = amdgpu_gem_prime_pin,
>>>>>> .gem_prime_unpin = amdgpu_gem_prime_unpin,
>>>>>> .gem_prime_res_obj = amdgpu_gem_prime_res_obj, diff --git
>>>>>> a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
>>>>>> index ae9c106..de6f599 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
>>>>>> @@ -26,6 +26,7 @@
>>>>>> #include <drm/drmP.h>
>>>>>> #include "amdgpu.h"
>>>>>> +#include "amdgpu_display.h"
>>>>>> #include <drm/amdgpu_drm.h>
>>>>>> #include <linux/dma-buf.h>
>>>>>> @@ -164,6 +165,33 @@ struct reservation_object
>>>>>> *amdgpu_gem_prime_res_obj(struct drm_gem_object *obj)
>>>>>> return bo->tbo.resv;
>>>>>> }
>>>>>> +static int amdgpu_gem_begin_cpu_access(struct dma_buf *dma_buf, enum
>>>>>> +dma_data_direction direction) {
>>>>>> + struct amdgpu_bo *bo = gem_to_amdgpu_bo(dma_buf->priv);
>>>>>> + struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>>>>>> + struct ttm_operation_ctx ctx = { true, false };
>>>>>> + u32 domain = amdgpu_framebuffer_domains(adev);
>>>>>> + long ret = 0;
>>>>>> + bool reads = (direction == DMA_BIDIRECTIONAL || direction ==
>>>>>> +DMA_FROM_DEVICE);
>>>>>> +
>>>>>> + if (!reads || !(domain | AMDGPU_GEM_DOMAIN_GTT) || bo->pin_count)
>>>>>> + return 0;
>>>>>> +
>>>>>> + /* move to gtt */
>>>>>> + ret = amdgpu_bo_reserve(bo, false);
>>>>>> + if (unlikely(ret != 0))
>>>>>> + return ret;
>>>>>> +
>>>>>> + amdgpu_ttm_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_GTT);
>>>>>> + ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
>>>>>> +
>>>>>> + amdgpu_bo_unreserve(bo);
>>>>>> + return ret;
>>>>>> +}
>>>>>> +
>>>>>> +static struct dma_buf_ops amdgpu_dmabuf_ops; static atomic_t aops_lock;
>>>>>> +
>>>>>> struct dma_buf *amdgpu_gem_prime_export(struct drm_device *dev,
>>>>>> struct drm_gem_object *gobj,
>>>>>> int flags)
>>>>>> @@ -178,5 +206,35 @@ struct dma_buf *amdgpu_gem_prime_export(struct
>>>>>> drm_device *dev,
>>>>>> buf = drm_gem_prime_export(dev, gobj, flags);
>>>>>> if (!IS_ERR(buf))
>>>>>> buf->file->f_mapping = dev->anon_inode->i_mapping;
>>>>>> +
>>>>>> + while (amdgpu_dmabuf_ops.begin_cpu_access !=
>>>>>> amdgpu_gem_begin_cpu_access)
>>>>>> + {
>>>>>> + if (!atomic_cmpxchg(&aops_lock, 0, 1)) {
>>>>>> + amdgpu_dmabuf_ops = *(buf->ops);
>>>>>> + amdgpu_dmabuf_ops.begin_cpu_access =
>>>>>> amdgpu_gem_begin_cpu_access;
>>>>>> + }
>>>>>> + }
>>>>>> + buf->ops = &amdgpu_dmabuf_ops;
>>>>>> +
>>>>>> return buf;
>>>>>> }
>>>>>> +
>>>>>> +struct drm_gem_object *amdgpu_gem_prime_import(struct drm_device *dev,
>>>>>> + struct dma_buf *dma_buf)
>>>>>> +{
>>>>>> + struct drm_gem_object *obj;
>>>>>> +
>>>>>> + if (dma_buf->ops == &amdgpu_dmabuf_ops) {
>>>>>> + obj = dma_buf->priv;
>>>>>> + if (obj->dev == dev) {
>>>>>> + /*
>>>>>> + * Importing dmabuf exported from out own gem increases
>>>>>> + * refcount on gem itself instead of f_count of dmabuf.
>>>>>> + */
>>>>>> + drm_gem_object_get(obj);
>>>>>> + return obj;
>>>>>> + }
>>>>>> + }
>>>>>> +
>>>>>> + return drm_gem_prime_import(dev, dma_buf); }
>>>>>> --
>>>>>> 2.7.4
>>>>>>
>
>From 95a211bd0a6bfea56e49670842addd3a02a76063 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <[email protected]>
Date: Wed, 13 Dec 2017 11:22:05 +0100
Subject: [PATCH] drm/prime: forward begin_cpu_access callback to drivers
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Allow drivers to implement their own begin_cpu_access callback.
Signed-off-by: Christian König <[email protected]>
---
drivers/gpu/drm/drm_prime.c | 11 +++++++++++
include/drm/drm_drv.h | 2 ++
2 files changed, 13 insertions(+)
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 8de93a226c24..3bf497e489f1 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -346,6 +346,16 @@ void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
}
EXPORT_SYMBOL(drm_gem_dmabuf_release);
+static void drm_gem_dmabuf_begin_cpu_access(struct dma_buf *dma_buf,
+ enum dma_data_direction direction)
+{
+ struct drm_gem_object *obj = dma_buf->priv;
+ struct drm_device *dev = obj->dev;
+
+ if (dev->driver->gem_prime_begin_cpu_access);
+ dev->driver->gem_prime_begin_cpu_access(obj, direction);
+}
+
static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
{
struct drm_gem_object *obj = dma_buf->priv;
@@ -403,6 +413,7 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
.map_dma_buf = drm_gem_map_dma_buf,
.unmap_dma_buf = drm_gem_unmap_dma_buf,
.release = drm_gem_dmabuf_release,
+ .begin_cpu_access = drm_gem_dmabuf_begin_cpu_access,
.map = drm_gem_dmabuf_kmap,
.map_atomic = drm_gem_dmabuf_kmap_atomic,
.unmap = drm_gem_dmabuf_kunmap,
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index d32b688eb346..6fb8b80f4349 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -490,6 +490,8 @@ struct drm_driver {
struct drm_device *dev,
struct dma_buf_attachment *attach,
struct sg_table *sgt);
+ void (*gem_prime_begin_cpu_access)(struct drm_gem_object *obj,
+ enum dma_data_direction direction);
void *(*gem_prime_vmap)(struct drm_gem_object *obj);
void (*gem_prime_vunmap)(struct drm_gem_object *obj, void *vaddr);
int (*gem_prime_mmap)(struct drm_gem_object *obj,
--
2.11.0
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