On 8/28/2019 12:40 AM, Animesh Manna wrote:
The function will internally get the gem buffer from global GTT
This patch adds a function, which will internally get the gem buffer for
DSB engine.
which is mapped in cpu domain to feed the data + opcode for DSB engine.
This GEM buffer is from global GTT, and is mapped into CPU domain,
contains the data + opcode to be fed 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)
Cc: Imre Deak <imre.deak@xxxxxxxxx>
Cc: Michel Thierry <michel.thierry@xxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Animesh Manna <animesh.manna@xxxxxxxxx>
---
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 96514dcc7812..0ab3516b0044 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1026,6 +1026,9 @@ 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 000000000000..a2845df90573
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_dsb.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2019 Intel Corporation
+ *
+ */
+
Any particular reason we don't have the traditional license here, like
other files ?
+#include "../i915_drv.h"
This is not the way you should include this header. Take example from
other files in display folder.
+#include "intel_display_types.h"
+
+#define DSB_BUF_SIZE (2 * PAGE_SIZE)
Any particular reason for this 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;
+
+ WARN_ON(i >= MAX_DSB_PER_PIPE);
Its not possible to have i > MAX_DSB_PER_PIPE as per above logic, so it
should be WARN_ON(i == MAX_DSB_PER_PIPE);
Also, shouldn't we stop operation here (along with the warning) as
clearly the cmd_buf and dsb we are going to get, is garbage ? On
negative testing this may cause kernel panic also.
+
+ dsb = &crtc->dsb[i];
+ dsb->id = i;
+ dsb->crtc = crtc;
+ if (!HAS_DSB(i915))
+ return dsb;
This check should be the first line in this function. I am not sure why
do we want to extract dsb ptr if the platform doesn't even support DSB.
+
+ wakeref = intel_runtime_pm_get(&i915->runtime_pm);
+
+ obj = i915_gem_object_create_internal(i915, DSB_BUF_SIZE);
+ if (IS_ERR(obj))
+ goto err;
+
+ mutex_lock(&i915->drm.struct_mutex);
+ vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, PIN_MAPPABLE);
+ mutex_unlock(&i915->drm.struct_mutex);
+ if (IS_ERR(vma)) {
+ DRM_DEBUG_KMS("Vma creation failed.\n");
+ i915_gem_object_put(obj);
Shouldn't gem_object_put() be inside mutex ?
+ goto err;
+ }
+
+ dsb->cmd_buf = i915_gem_object_pin_map(vma->obj, I915_MAP_WC);
+ if (IS_ERR(dsb->cmd_buf)) {
+ DRM_DEBUG_KMS("Command buffer creation failed.\n");
+ dsb->cmd_buf = NULL;
Why don't we have a i915_gem_object_put(obj) here ?
+ goto err;
+ }
+ dsb->vma = vma;
+
+err:
I think we should have a i915_gem_object_put(obj) for all error cases here.
+ intel_runtime_pm_put(&i915->runtime_pm, wakeref);
+ return dsb;
Again, we are returning a dsb ptr in all cases. As this patch doesn't
have the caller function, I can't understand why are we returning the
same ptr in both success or failure cases, but I would prefer a
dsb_get() function which returns NULL on failure, dsb* on success.
+}
+
+void intel_dsb_put(struct intel_dsb *dsb)
+{
+ struct intel_crtc *crtc;
+ struct drm_i915_private *i915;
+ struct i915_vma *vma;
+
+ if (!dsb)
+ return;
So the get() API returns a non-NULL pointer in both success and failure
cases, but put() can have a NULL ptr as input. Looks a bit asymmetrical
design. Also, we should add API documentation on top of the function
now, as we need to understand what can be the return values of the
function.
+
+ crtc = dsb->crtc;
+ i915 = to_i915(crtc->base.dev);
+
+ if (dsb->cmd_buf) {
+ vma = dsb->vma;
+ mutex_lock(&i915->drm.struct_mutex);
+ i915_gem_object_unpin_map(vma->obj);
+ i915_vma_unpin_and_release(&vma, 0);
+ dsb->cmd_buf = NULL;
+ mutex_unlock(&i915->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 000000000000..4a4091cadc1e
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_dsb.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
Same as above for license.
+ */
+
+#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
The Bspec says there are 3 DSB DMA engines per pipe, and we have defined
MAX_DSB_PER_PIPE = 3 (and the count starts from 0), which means we
should be running our loops always < MAX_DSB_PER_PIPE. I would prefer
this to be either INVALID_DSB = 0 and DSB3 = MAX_DSB = 3, but this is
just a soft requirement, you can pick or ignore.
+};
+
+struct intel_dsb {
+ struct intel_crtc *crtc;
+ enum dsb_id id;
Note that your INVALID_DSB id is -1 not 0. This means all the intel_dsb
structures will be initialized with id=DSB1 not INVALID_DSB.
+ u32 *cmd_buf;
+ struct i915_vma *vma;
+};
+
This could also be the place to add doc about the get/put functions.
+struct intel_dsb *
+intel_dsb_get(struct intel_crtc *crtc);
+void intel_dsb_put(struct intel_dsb *dsb);
+
+#endif
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d32cfdb78b74..dd6cfb89b830 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -67,6 +67,7 @@
#include "display/intel_display.h"
#include "display/intel_display_power.h"
#include "display/intel_dpll_mgr.h"
+#include "display/intel_dsb.h"
No external element is using get() / put() functions yet, this change
should go into a patch, which is using the functions.
- Shashank
#include "display/intel_frontbuffer.h"
#include "display/intel_gmbus.h"
#include "display/intel_opregion.h"
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