Re: [Intel-gfx] [PATCH v4 02/10] drm/i915/dsb: DSB context creation.

2019-09-03 Thread Jani Nikula
On Tue, 03 Sep 2019, Animesh Manna  wrote:
> Hi,
>
>
> On 8/30/2019 7:05 PM, Jani Nikula wrote:
>> On Fri, 30 Aug 2019, Animesh Manna  wrote:
>>> This patch adds a function, which will internally get the gem buffer
>>> for DSB engine. The GEM buffer is from global GTT, and is mapped into
>>> CPU domain, contains the data + opcode to be feed to DSB engine.
>>>
>>> v1: Initial version.
>>>
>>> v2:
>>> - removed some unwanted code. (Chris)
>>> - Used i915_gem_object_create_internal instead of _shmem. (Chris)
>>> - cmd_buf_tail removed and can be derived through vma object. (Chris)
>>>
>>> v3: vma realeased if i915_gem_object_pin_map() failed. (Shashank)
>>>
>>> Cc: Imre Deak 
>>> Cc: Michel Thierry 
>>> Cc: Jani Nikula 
>>> Cc: Rodrigo Vivi 
>>> Signed-off-by: Animesh Manna 
>>> ---
>>>   drivers/gpu/drm/i915/Makefile |  1 +
>>>   .../drm/i915/display/intel_display_types.h|  3 +
>>>   drivers/gpu/drm/i915/display/intel_dsb.c  | 83 +++
>>>   drivers/gpu/drm/i915/display/intel_dsb.h  | 31 +++
>>>   drivers/gpu/drm/i915/i915_drv.h   |  1 +
>>>   5 files changed, 119 insertions(+)
>>>   create mode 100644 drivers/gpu/drm/i915/display/intel_dsb.c
>>>   create mode 100644 drivers/gpu/drm/i915/display/intel_dsb.h
>>>
>>> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
>>> index 658b930d34a8..6313e7b4bd78 100644
>>> --- a/drivers/gpu/drm/i915/Makefile
>>> +++ b/drivers/gpu/drm/i915/Makefile
>>> @@ -172,6 +172,7 @@ i915-y += \
>>> display/intel_display_power.o \
>>> display/intel_dpio_phy.o \
>>> display/intel_dpll_mgr.o \
>>> +   display/intel_dsb.o \
>>> display/intel_fbc.o \
>>> display/intel_fifo_underrun.o \
>>> display/intel_frontbuffer.o \
>>> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h 
>>> b/drivers/gpu/drm/i915/display/intel_display_types.h
>>> index 61277a87dbe7..da36867189cb 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
>>> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
>>> @@ -1033,6 +1033,9 @@ struct intel_crtc {
>>>   
>>> /* scalers available on this crtc */
>>> int num_scalers;
>>> +
>>> +   /* per pipe DSB related info */
>>> +   struct intel_dsb dsb[MAX_DSB_PER_PIPE];
>>>   };
>>>   
>>>   struct intel_plane {
>>> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c 
>>> b/drivers/gpu/drm/i915/display/intel_dsb.c
>>> new file mode 100644
>>> index ..007ef13481d5
>>> --- /dev/null
>>> +++ b/drivers/gpu/drm/i915/display/intel_dsb.c
>>> @@ -0,0 +1,83 @@
>>> +// SPDX-License-Identifier: MIT
>>> +/*
>>> + * Copyright © 2019 Intel Corporation
>>> + *
>>> + */
>>> +
>>> +#include "i915_drv.h"
>>> +#include "intel_display_types.h"
>>> +
>>> +#define DSB_BUF_SIZE(2 * PAGE_SIZE)
>>> +
>>> +struct intel_dsb *
>>> +intel_dsb_get(struct intel_crtc *crtc)
>>> +{
>>> +   struct drm_device *dev = crtc->base.dev;
>>> +   struct drm_i915_private *i915 = to_i915(dev);
>>> +   struct drm_i915_gem_object *obj;
>>> +   struct i915_vma *vma;
>>> +   struct intel_dsb *dsb;
>>> +   intel_wakeref_t wakeref;
>>> +   int i;
>>> +
>>> +   for (i = 0; i < MAX_DSB_PER_PIPE; i++)
>>> +   if (!crtc->dsb[i].cmd_buf)
>>> +   break;
>>> +
>>> +   if (WARN_ON(i == MAX_DSB_PER_PIPE))
>>> +   return NULL;
>>> +
>>> +   dsb = >dsb[i];
>>> +   dsb->id = i;
>>> +   dsb->crtc = crtc;
>>> +   if (!HAS_DSB(i915))
>>> +   return dsb;
>> Why do you go through any of the trouble if there is no DSB? Just early
>> return NULL, and make the write functions handle NULL dsb pointer.
>
> Handing NULL dsb pointer in write function is easy, but getting dev_priv 
> which is needed for I915_WRITE is tricky with the following function 
> prototypes which were agreed (I can understand  it was discussed long 
> back, so added below). Good to get your suggestion here.
>
> struct intel_dsb * intel_dsb_get(struct intel_crtc *crtc);
> void intel_dsb_put(struct intel_dsb *dsb);
> void intel_dsb_reg_write(struct intel_dsb *dsb, i915_reg_t reg, u32 val);
> void intel_dsb_indexed_reg_write(struct intel_dsb *dsb, i915_reg_t reg, 
> u32 val);
> void intel_dsb_commit(struct intel_dsb *dsb);

Right, silly me. Need to ensure you have a fallback dsb that always has
the crtc in place to figure out i915. Both are a bit meh, but I lean
towards the latter.

BR,
Jani.

>
> Regards,
> Animesh
>
>
>>
>>> +
>>> +   wakeref = intel_runtime_pm_get(>runtime_pm);
>>> +
>>> +   obj = i915_gem_object_create_internal(i915, DSB_BUF_SIZE);
>>> +   if (IS_ERR(obj))
>>> +   goto err;
>>> +
>>> +   mutex_lock(>drm.struct_mutex);
>>> +   vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, PIN_MAPPABLE);
>>> +   mutex_unlock(>drm.struct_mutex);
>>> +   if (IS_ERR(vma)) {
>>> +   DRM_ERROR("Vma creation failed.\n");
>>> +   i915_gem_object_put(obj);
>>> +   goto err;
>>> +   }
>>> +
>>> +   dsb->cmd_buf = i915_gem_object_pin_map(vma->obj, 

Re: [Intel-gfx] [PATCH v4 02/10] drm/i915/dsb: DSB context creation.

2019-09-03 Thread Animesh Manna

Hi,


On 8/30/2019 7:05 PM, Jani Nikula wrote:

On Fri, 30 Aug 2019, Animesh Manna  wrote:

This patch adds a function, which will internally get the gem buffer
for DSB engine. The GEM buffer is from global GTT, and is mapped into
CPU domain, contains the data + opcode to be feed to DSB engine.

v1: Initial version.

v2:
- removed some unwanted code. (Chris)
- Used i915_gem_object_create_internal instead of _shmem. (Chris)
- cmd_buf_tail removed and can be derived through vma object. (Chris)

v3: vma realeased if i915_gem_object_pin_map() failed. (Shashank)

Cc: Imre Deak 
Cc: Michel Thierry 
Cc: Jani Nikula 
Cc: Rodrigo Vivi 
Signed-off-by: Animesh Manna 
---
  drivers/gpu/drm/i915/Makefile |  1 +
  .../drm/i915/display/intel_display_types.h|  3 +
  drivers/gpu/drm/i915/display/intel_dsb.c  | 83 +++
  drivers/gpu/drm/i915/display/intel_dsb.h  | 31 +++
  drivers/gpu/drm/i915/i915_drv.h   |  1 +
  5 files changed, 119 insertions(+)
  create mode 100644 drivers/gpu/drm/i915/display/intel_dsb.c
  create mode 100644 drivers/gpu/drm/i915/display/intel_dsb.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 658b930d34a8..6313e7b4bd78 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -172,6 +172,7 @@ i915-y += \
display/intel_display_power.o \
display/intel_dpio_phy.o \
display/intel_dpll_mgr.o \
+   display/intel_dsb.o \
display/intel_fbc.o \
display/intel_fifo_underrun.o \
display/intel_frontbuffer.o \
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h 
b/drivers/gpu/drm/i915/display/intel_display_types.h
index 61277a87dbe7..da36867189cb 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1033,6 +1033,9 @@ struct intel_crtc {
  
  	/* scalers available on this crtc */

int num_scalers;
+
+   /* per pipe DSB related info */
+   struct intel_dsb dsb[MAX_DSB_PER_PIPE];
  };
  
  struct intel_plane {

diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c 
b/drivers/gpu/drm/i915/display/intel_dsb.c
new file mode 100644
index ..007ef13481d5
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_dsb.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2019 Intel Corporation
+ *
+ */
+
+#include "i915_drv.h"
+#include "intel_display_types.h"
+
+#define DSB_BUF_SIZE(2 * PAGE_SIZE)
+
+struct intel_dsb *
+intel_dsb_get(struct intel_crtc *crtc)
+{
+   struct drm_device *dev = crtc->base.dev;
+   struct drm_i915_private *i915 = to_i915(dev);
+   struct drm_i915_gem_object *obj;
+   struct i915_vma *vma;
+   struct intel_dsb *dsb;
+   intel_wakeref_t wakeref;
+   int i;
+
+   for (i = 0; i < MAX_DSB_PER_PIPE; i++)
+   if (!crtc->dsb[i].cmd_buf)
+   break;
+
+   if (WARN_ON(i == MAX_DSB_PER_PIPE))
+   return NULL;
+
+   dsb = >dsb[i];
+   dsb->id = i;
+   dsb->crtc = crtc;
+   if (!HAS_DSB(i915))
+   return dsb;

Why do you go through any of the trouble if there is no DSB? Just early
return NULL, and make the write functions handle NULL dsb pointer.


Handing NULL dsb pointer in write function is easy, but getting dev_priv 
which is needed for I915_WRITE is tricky with the following function 
prototypes which were agreed (I can understand  it was discussed long 
back, so added below). Good to get your suggestion here.


struct intel_dsb * intel_dsb_get(struct intel_crtc *crtc);
void intel_dsb_put(struct intel_dsb *dsb);
void intel_dsb_reg_write(struct intel_dsb *dsb, i915_reg_t reg, u32 val);
void intel_dsb_indexed_reg_write(struct intel_dsb *dsb, i915_reg_t reg, 
u32 val);

void intel_dsb_commit(struct intel_dsb *dsb);

Regards,
Animesh





+
+   wakeref = intel_runtime_pm_get(>runtime_pm);
+
+   obj = i915_gem_object_create_internal(i915, DSB_BUF_SIZE);
+   if (IS_ERR(obj))
+   goto err;
+
+   mutex_lock(>drm.struct_mutex);
+   vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, PIN_MAPPABLE);
+   mutex_unlock(>drm.struct_mutex);
+   if (IS_ERR(vma)) {
+   DRM_ERROR("Vma creation failed.\n");
+   i915_gem_object_put(obj);
+   goto err;
+   }
+
+   dsb->cmd_buf = i915_gem_object_pin_map(vma->obj, I915_MAP_WC);
+   if (IS_ERR(dsb->cmd_buf)) {
+   DRM_ERROR("Command buffer creation failed.\n");
+   i915_vma_unpin_and_release(, 0);
+   dsb->cmd_buf = NULL;
+   goto err;
+   }
+   dsb->vma = vma;
+
+err:
+   intel_runtime_pm_put(>runtime_pm, wakeref);
+   return dsb;
+}
+
+void intel_dsb_put(struct intel_dsb *dsb)
+{
+   struct intel_crtc *crtc;
+   struct drm_i915_private *i915;
+
+   if (!dsb)
+   return;
+
+   crtc = dsb->crtc;
+   

Re: [Intel-gfx] [PATCH v4 02/10] drm/i915/dsb: DSB context creation.

2019-09-02 Thread Sharma, Shashank


> -Original Message-
> From: Intel-gfx [mailto:intel-gfx-boun...@lists.freedesktop.org] On Behalf Of 
> Jani
> Nikula
> Sent: Friday, August 30, 2019 7:06 PM
> To: Manna, Animesh ; intel-gfx@lists.freedesktop.org
> Cc: Thierry, Michel 
> Subject: Re: [Intel-gfx] [PATCH v4 02/10] drm/i915/dsb: DSB context creation.
> 
> On Fri, 30 Aug 2019, Animesh Manna  wrote:
> > This patch adds a function, which will internally get the gem buffer
> > for DSB engine. The GEM buffer is from global GTT, and is mapped into
> > CPU domain, contains the data + opcode to be feed to DSB engine.
> >
> > v1: Initial version.
> >
> > v2:
> > - removed some unwanted code. (Chris)
> > - Used i915_gem_object_create_internal instead of _shmem. (Chris)
> > - cmd_buf_tail removed and can be derived through vma object. (Chris)
> >
> > v3: vma realeased if i915_gem_object_pin_map() failed. (Shashank)
> >
> > Cc: Imre Deak 
> > Cc: Michel Thierry 
> > Cc: Jani Nikula 
> > Cc: Rodrigo Vivi 
> > Signed-off-by: Animesh Manna 
> > ---
> >  drivers/gpu/drm/i915/Makefile |  1 +
> >  .../drm/i915/display/intel_display_types.h|  3 +
> >  drivers/gpu/drm/i915/display/intel_dsb.c  | 83 +++
> >  drivers/gpu/drm/i915/display/intel_dsb.h  | 31 +++
> >  drivers/gpu/drm/i915/i915_drv.h   |  1 +
> >  5 files changed, 119 insertions(+)
> >  create mode 100644 drivers/gpu/drm/i915/display/intel_dsb.c
> >  create mode 100644 drivers/gpu/drm/i915/display/intel_dsb.h
> >
> > diff --git a/drivers/gpu/drm/i915/Makefile
> > b/drivers/gpu/drm/i915/Makefile index 658b930d34a8..6313e7b4bd78
> > 100644
> > --- a/drivers/gpu/drm/i915/Makefile
> > +++ b/drivers/gpu/drm/i915/Makefile
> > @@ -172,6 +172,7 @@ i915-y += \
> > display/intel_display_power.o \
> > display/intel_dpio_phy.o \
> > display/intel_dpll_mgr.o \
> > +   display/intel_dsb.o \
> > display/intel_fbc.o \
> > display/intel_fifo_underrun.o \
> > display/intel_frontbuffer.o \
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> > b/drivers/gpu/drm/i915/display/intel_display_types.h
> > index 61277a87dbe7..da36867189cb 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > @@ -1033,6 +1033,9 @@ struct intel_crtc {
> >
> > /* scalers available on this crtc */
> > int num_scalers;
> > +
> > +   /* per pipe DSB related info */
> > +   struct intel_dsb dsb[MAX_DSB_PER_PIPE];
> >  };
> >
> >  struct intel_plane {
> > diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c
> > b/drivers/gpu/drm/i915/display/intel_dsb.c
> > new file mode 100644
> > index ..007ef13481d5
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/display/intel_dsb.c
> > @@ -0,0 +1,83 @@
> > +// SPDX-License-Identifier: MIT
> > +/*
> > + * Copyright © 2019 Intel Corporation
> > + *
> > + */
> > +
> > +#include "i915_drv.h"
> > +#include "intel_display_types.h"
> > +
> > +#define DSB_BUF_SIZE(2 * PAGE_SIZE)
> > +
> > +struct intel_dsb *
> > +intel_dsb_get(struct intel_crtc *crtc) {
> > +   struct drm_device *dev = crtc->base.dev;
> > +   struct drm_i915_private *i915 = to_i915(dev);
> > +   struct drm_i915_gem_object *obj;
> > +   struct i915_vma *vma;
> > +   struct intel_dsb *dsb;
> > +   intel_wakeref_t wakeref;
> > +   int i;
> > +
> > +   for (i = 0; i < MAX_DSB_PER_PIPE; i++)
> > +   if (!crtc->dsb[i].cmd_buf)
> > +   break;
> > +
> > +   if (WARN_ON(i == MAX_DSB_PER_PIPE))
> > +   return NULL;
> > +
> > +   dsb = >dsb[i];
> > +   dsb->id = i;
> > +   dsb->crtc = crtc;
> > +   if (!HAS_DSB(i915))
> > +   return dsb;
> 
> Why do you go through any of the trouble if there is no DSB? Just early 
> return NULL,
> and make the write functions handle NULL dsb pointer.
> 
I agree on this. Even I thought it would be better if we populate the DSB ptr 
only when we find a valid DSB support on the platform. And the caller of get() 
can understand this and act accordingly. 
> > +
> > +   wakeref = intel_runtime_pm_get(>runtime_pm);
> > +
> > +   obj = i915_gem_object_create_internal(i915, DSB_BUF_SIZE);
> > +   if (IS_ERR(obj))
> > +   goto err;
> > +
> > +   mutex_lock(>drm.struct_mutex);
>

Re: [Intel-gfx] [PATCH v4 02/10] drm/i915/dsb: DSB context creation.

2019-08-30 Thread Jani Nikula
On Fri, 30 Aug 2019, Animesh Manna  wrote:
> This patch adds a function, which will internally get the gem buffer
> for DSB engine. The GEM buffer is from global GTT, and is mapped into
> CPU domain, contains the data + opcode to be feed to DSB engine.
>
> v1: Initial version.
>
> v2:
> - removed some unwanted code. (Chris)
> - Used i915_gem_object_create_internal instead of _shmem. (Chris)
> - cmd_buf_tail removed and can be derived through vma object. (Chris)
>
> v3: vma realeased if i915_gem_object_pin_map() failed. (Shashank)
>
> Cc: Imre Deak 
> Cc: Michel Thierry 
> Cc: Jani Nikula 
> Cc: Rodrigo Vivi 
> Signed-off-by: Animesh Manna 
> ---
>  drivers/gpu/drm/i915/Makefile |  1 +
>  .../drm/i915/display/intel_display_types.h|  3 +
>  drivers/gpu/drm/i915/display/intel_dsb.c  | 83 +++
>  drivers/gpu/drm/i915/display/intel_dsb.h  | 31 +++
>  drivers/gpu/drm/i915/i915_drv.h   |  1 +
>  5 files changed, 119 insertions(+)
>  create mode 100644 drivers/gpu/drm/i915/display/intel_dsb.c
>  create mode 100644 drivers/gpu/drm/i915/display/intel_dsb.h
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 658b930d34a8..6313e7b4bd78 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -172,6 +172,7 @@ i915-y += \
>   display/intel_display_power.o \
>   display/intel_dpio_phy.o \
>   display/intel_dpll_mgr.o \
> + display/intel_dsb.o \
>   display/intel_fbc.o \
>   display/intel_fifo_underrun.o \
>   display/intel_frontbuffer.o \
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h 
> b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 61277a87dbe7..da36867189cb 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1033,6 +1033,9 @@ struct intel_crtc {
>  
>   /* scalers available on this crtc */
>   int num_scalers;
> +
> + /* per pipe DSB related info */
> + struct intel_dsb dsb[MAX_DSB_PER_PIPE];
>  };
>  
>  struct intel_plane {
> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c 
> b/drivers/gpu/drm/i915/display/intel_dsb.c
> new file mode 100644
> index ..007ef13481d5
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/display/intel_dsb.c
> @@ -0,0 +1,83 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2019 Intel Corporation
> + *
> + */
> +
> +#include "i915_drv.h"
> +#include "intel_display_types.h"
> +
> +#define DSB_BUF_SIZE(2 * PAGE_SIZE)
> +
> +struct intel_dsb *
> +intel_dsb_get(struct intel_crtc *crtc)
> +{
> + struct drm_device *dev = crtc->base.dev;
> + struct drm_i915_private *i915 = to_i915(dev);
> + struct drm_i915_gem_object *obj;
> + struct i915_vma *vma;
> + struct intel_dsb *dsb;
> + intel_wakeref_t wakeref;
> + int i;
> +
> + for (i = 0; i < MAX_DSB_PER_PIPE; i++)
> + if (!crtc->dsb[i].cmd_buf)
> + break;
> +
> + if (WARN_ON(i == MAX_DSB_PER_PIPE))
> + return NULL;
> +
> + dsb = >dsb[i];
> + dsb->id = i;
> + dsb->crtc = crtc;
> + if (!HAS_DSB(i915))
> + return dsb;

Why do you go through any of the trouble if there is no DSB? Just early
return NULL, and make the write functions handle NULL dsb pointer.

> +
> + wakeref = intel_runtime_pm_get(>runtime_pm);
> +
> + obj = i915_gem_object_create_internal(i915, DSB_BUF_SIZE);
> + if (IS_ERR(obj))
> + goto err;
> +
> + mutex_lock(>drm.struct_mutex);
> + vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, PIN_MAPPABLE);
> + mutex_unlock(>drm.struct_mutex);
> + if (IS_ERR(vma)) {
> + DRM_ERROR("Vma creation failed.\n");
> + i915_gem_object_put(obj);
> + goto err;
> + }
> +
> + dsb->cmd_buf = i915_gem_object_pin_map(vma->obj, I915_MAP_WC);
> + if (IS_ERR(dsb->cmd_buf)) {
> + DRM_ERROR("Command buffer creation failed.\n");
> + i915_vma_unpin_and_release(, 0);
> + dsb->cmd_buf = NULL;
> + goto err;
> + }
> + dsb->vma = vma;
> +
> +err:
> + intel_runtime_pm_put(>runtime_pm, wakeref);
> + return dsb;
> +}
> +
> +void intel_dsb_put(struct intel_dsb *dsb)
> +{
> + struct intel_crtc *crtc;
> + struct drm_i915_private *i915;
> +
> + if (!dsb)
> + return;
> +
> + crtc = dsb->crtc;
> + i915 = to_i915(crtc->base.dev);
> +
> + if (dsb->cmd_buf) {
> + mutex_lock(>drm.struct_mutex);
> + i915_gem_object_unpin_map(dsb->vma->obj);
> + i915_vma_unpin_and_release(>vma, 0);
> + dsb->cmd_buf = NULL;
> + mutex_unlock(>drm.struct_mutex);
> + }
> +}
> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.h 
> b/drivers/gpu/drm/i915/display/intel_dsb.h
> new file mode 100644
> index ..4a4091cadc1e
> --- /dev/null
> +++ 

[Intel-gfx] [PATCH v4 02/10] drm/i915/dsb: DSB context creation.

2019-08-30 Thread Animesh Manna
This patch adds a function, which will internally get the gem buffer
for DSB engine. The GEM buffer is from global GTT, and is mapped into
CPU domain, contains the data + opcode to be feed to DSB engine.

v1: Initial version.

v2:
- removed some unwanted code. (Chris)
- Used i915_gem_object_create_internal instead of _shmem. (Chris)
- cmd_buf_tail removed and can be derived through vma object. (Chris)

v3: vma realeased if i915_gem_object_pin_map() failed. (Shashank)

Cc: Imre Deak 
Cc: Michel Thierry 
Cc: Jani Nikula 
Cc: Rodrigo Vivi 
Signed-off-by: Animesh Manna 
---
 drivers/gpu/drm/i915/Makefile |  1 +
 .../drm/i915/display/intel_display_types.h|  3 +
 drivers/gpu/drm/i915/display/intel_dsb.c  | 83 +++
 drivers/gpu/drm/i915/display/intel_dsb.h  | 31 +++
 drivers/gpu/drm/i915/i915_drv.h   |  1 +
 5 files changed, 119 insertions(+)
 create mode 100644 drivers/gpu/drm/i915/display/intel_dsb.c
 create mode 100644 drivers/gpu/drm/i915/display/intel_dsb.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 658b930d34a8..6313e7b4bd78 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -172,6 +172,7 @@ i915-y += \
display/intel_display_power.o \
display/intel_dpio_phy.o \
display/intel_dpll_mgr.o \
+   display/intel_dsb.o \
display/intel_fbc.o \
display/intel_fifo_underrun.o \
display/intel_frontbuffer.o \
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h 
b/drivers/gpu/drm/i915/display/intel_display_types.h
index 61277a87dbe7..da36867189cb 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1033,6 +1033,9 @@ struct intel_crtc {
 
/* scalers available on this crtc */
int num_scalers;
+
+   /* per pipe DSB related info */
+   struct intel_dsb dsb[MAX_DSB_PER_PIPE];
 };
 
 struct intel_plane {
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c 
b/drivers/gpu/drm/i915/display/intel_dsb.c
new file mode 100644
index ..007ef13481d5
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_dsb.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2019 Intel Corporation
+ *
+ */
+
+#include "i915_drv.h"
+#include "intel_display_types.h"
+
+#define DSB_BUF_SIZE(2 * PAGE_SIZE)
+
+struct intel_dsb *
+intel_dsb_get(struct intel_crtc *crtc)
+{
+   struct drm_device *dev = crtc->base.dev;
+   struct drm_i915_private *i915 = to_i915(dev);
+   struct drm_i915_gem_object *obj;
+   struct i915_vma *vma;
+   struct intel_dsb *dsb;
+   intel_wakeref_t wakeref;
+   int i;
+
+   for (i = 0; i < MAX_DSB_PER_PIPE; i++)
+   if (!crtc->dsb[i].cmd_buf)
+   break;
+
+   if (WARN_ON(i == MAX_DSB_PER_PIPE))
+   return NULL;
+
+   dsb = >dsb[i];
+   dsb->id = i;
+   dsb->crtc = crtc;
+   if (!HAS_DSB(i915))
+   return dsb;
+
+   wakeref = intel_runtime_pm_get(>runtime_pm);
+
+   obj = i915_gem_object_create_internal(i915, DSB_BUF_SIZE);
+   if (IS_ERR(obj))
+   goto err;
+
+   mutex_lock(>drm.struct_mutex);
+   vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, PIN_MAPPABLE);
+   mutex_unlock(>drm.struct_mutex);
+   if (IS_ERR(vma)) {
+   DRM_ERROR("Vma creation failed.\n");
+   i915_gem_object_put(obj);
+   goto err;
+   }
+
+   dsb->cmd_buf = i915_gem_object_pin_map(vma->obj, I915_MAP_WC);
+   if (IS_ERR(dsb->cmd_buf)) {
+   DRM_ERROR("Command buffer creation failed.\n");
+   i915_vma_unpin_and_release(, 0);
+   dsb->cmd_buf = NULL;
+   goto err;
+   }
+   dsb->vma = vma;
+
+err:
+   intel_runtime_pm_put(>runtime_pm, wakeref);
+   return dsb;
+}
+
+void intel_dsb_put(struct intel_dsb *dsb)
+{
+   struct intel_crtc *crtc;
+   struct drm_i915_private *i915;
+
+   if (!dsb)
+   return;
+
+   crtc = dsb->crtc;
+   i915 = to_i915(crtc->base.dev);
+
+   if (dsb->cmd_buf) {
+   mutex_lock(>drm.struct_mutex);
+   i915_gem_object_unpin_map(dsb->vma->obj);
+   i915_vma_unpin_and_release(>vma, 0);
+   dsb->cmd_buf = NULL;
+   mutex_unlock(>drm.struct_mutex);
+   }
+}
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.h 
b/drivers/gpu/drm/i915/display/intel_dsb.h
new file mode 100644
index ..4a4091cadc1e
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_dsb.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#ifndef _INTEL_DSB_H
+#define _INTEL_DSB_H
+
+struct intel_crtc;
+struct i915_vma;
+
+enum dsb_id {
+   INVALID_DSB = -1,
+   DSB1,
+   DSB2,
+   DSB3,
+   MAX_DSB_PER_PIPE
+};
+
+struct