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drm/vc4: Rework UPM allocation to avoid double buffering
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The previous UPM allocation was done per plane state, when
there is no overlap of usage between frames.

Allocate per plane, and only change the allocation if the required
size changes. We have to reference count as plane states can
be duplicated.

Signed-off-by: Dave Stevenson <[email protected]>
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@6by9
6by9 committed Sep 25, 2024
1 parent 0fb3c83 commit 55fbfc1
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Showing 3 changed files with 87 additions and 30 deletions.
19 changes: 16 additions & 3 deletions drivers/gpu/drm/vc4/vc4_drv.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -322,6 +322,21 @@ struct vc4_v3d {
struct debugfs_regset32 regset;
};

#define VC4_NUM_UPM_HANDLES 32
struct vc4_upm_refcounts {
refcount_t refcount;

/* UPM handle index */
unsigned int index;
/* Allocation size */
size_t size;
/* Our allocation in UPM for prefetching. */
struct drm_mm_node upm;

/* Pointer back to the HVS structure */
struct vc4_hvs *hvs;
};

#define HVS_NUM_CHANNELS 3

struct vc4_hvs {
Expand Down Expand Up @@ -351,6 +366,7 @@ struct vc4_hvs {
/* Memory manager for the UPM memory used for prefetching. */
struct drm_mm upm_mm;
struct ida upm_handles;
struct vc4_upm_refcounts upm_refcounts[VC4_NUM_UPM_HANDLES];

spinlock_t mm_lock;

Expand Down Expand Up @@ -446,9 +462,6 @@ struct vc4_plane_state {
bool is_unity;
bool is_yuv;

/* Our allocation in UPM for prefetching. */
struct drm_mm_node upm[DRM_FORMAT_MAX_PLANES];

/* The Unified Pre-Fetcher Handle */
unsigned int upm_handle[DRM_FORMAT_MAX_PLANES];

Expand Down
7 changes: 7 additions & 0 deletions drivers/gpu/drm/vc4/vc4_hvs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1754,6 +1754,7 @@ struct vc4_hvs *__vc4_hvs_alloc(struct vc4_dev *vc4,
unsigned int dlist_start;
size_t dlist_size;
size_t lbm_size;
unsigned int i;

hvs = drmm_kzalloc(drm, sizeof(*hvs), GFP_KERNEL);
if (!hvs)
Expand Down Expand Up @@ -1793,6 +1794,12 @@ struct vc4_hvs *__vc4_hvs_alloc(struct vc4_dev *vc4,
else
dlist_size = 4096;

for (i = 0; i < VC4_NUM_UPM_HANDLES; i++) {
refcount_set(&hvs->upm_refcounts[i].refcount, 0);
hvs->upm_refcounts[i].index = i;
hvs->upm_refcounts[i].hvs = hvs;
}

break;

default:
Expand Down
91 changes: 64 additions & 27 deletions drivers/gpu/drm/vc4/vc4_plane.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -278,6 +278,8 @@ static bool plane_enabled(struct drm_plane_state *state)

struct drm_plane_state *vc4_plane_duplicate_state(struct drm_plane *plane)
{
struct vc4_dev *vc4 = to_vc4_dev(plane->dev);
struct vc4_hvs *hvs = vc4->hvs;
struct vc4_plane_state *vc4_state;
unsigned int i;

Expand All @@ -288,10 +290,10 @@ struct drm_plane_state *vc4_plane_duplicate_state(struct drm_plane *plane)
if (!vc4_state)
return NULL;

memset(&vc4_state->upm, 0, sizeof(vc4_state->upm));

for (i = 0; i < DRM_FORMAT_MAX_PLANES; i++)
vc4_state->upm_handle[i] = 0;
for (i = 0; i < DRM_FORMAT_MAX_PLANES; i++) {
if (vc4_state->upm_handle[i])
refcount_inc(&hvs->upm_refcounts[vc4_state->upm_handle[i]].refcount);
}

vc4_state->dlist_initialized = 0;

Expand All @@ -311,6 +313,19 @@ struct drm_plane_state *vc4_plane_duplicate_state(struct drm_plane *plane)
return &vc4_state->base;
}

void vc4_plane_release_upm_ida(struct vc4_hvs *hvs, struct vc4_upm_refcounts *refcount)
{
unsigned int upm_handle = refcount->index;
unsigned long irqflags;

spin_lock_irqsave(&hvs->mm_lock, irqflags);
drm_mm_remove_node(&refcount->upm);
spin_unlock_irqrestore(&hvs->mm_lock, irqflags);

if (upm_handle > 0)
ida_free(&hvs->upm_handles, upm_handle);
}

void vc4_plane_destroy_state(struct drm_plane *plane,
struct drm_plane_state *state)
{
Expand All @@ -320,17 +335,15 @@ void vc4_plane_destroy_state(struct drm_plane *plane,
unsigned int i;

for (i = 0; i < DRM_FORMAT_MAX_PLANES; i++) {
unsigned long irqflags;
struct vc4_upm_refcounts *refcount;

if (!drm_mm_node_allocated(&vc4_state->upm[i]))
if (!vc4_state->upm_handle[i])
continue;

spin_lock_irqsave(&hvs->mm_lock, irqflags);
drm_mm_remove_node(&vc4_state->upm[i]);
spin_unlock_irqrestore(&hvs->mm_lock, irqflags);
refcount = &hvs->upm_refcounts[vc4_state->upm_handle[i]];

if (vc4_state->upm_handle[i] > 0)
ida_free(&hvs->upm_handles, vc4_state->upm_handle[i]);
if (refcount_dec_and_test(&refcount->refcount))
vc4_plane_release_upm_ida(hvs, refcount);
}

kfree(vc4_state->dlist);
Expand Down Expand Up @@ -945,32 +958,56 @@ static int vc6_plane_allocate_upm(struct drm_plane_state *state)
vc4_state->upm_buffer_lines = SCALER6_PTR0_UPM_BUFF_SIZE_2_LINES;

for (i = 0; i < info->num_planes; i++) {
struct vc4_upm_refcounts *refcount;
unsigned int upm_handle;
unsigned long irqflags;
size_t upm_size;

upm_size = vc6_upm_size(state, i);
if (!upm_size)
return -EINVAL;
upm_handle = vc4_state->upm_handle[i];

spin_lock_irqsave(&hvs->mm_lock, irqflags);
ret = drm_mm_insert_node_generic(&hvs->upm_mm,
&vc4_state->upm[i],
upm_size, HVS_UBM_WORD_SIZE,
0, 0);
spin_unlock_irqrestore(&hvs->mm_lock, irqflags);
if (ret) {
drm_err(drm, "Failed to allocate UPM entry: %d\n", ret);
return ret;
if (upm_handle &&
hvs->upm_refcounts[upm_handle].size == upm_size) {
/* Allocation is the same as the previous user of the
* plane. Copy the allocation.
*/
vc4_state->upm_handle[i] = upm_handle;
} else {
if (refcount_dec_and_test(&hvs->upm_refcounts[upm_handle].refcount))
vc4_plane_release_upm_ida(hvs, &hvs->upm_refcounts[upm_handle]);

upm_handle = ida_alloc_range(&hvs->upm_handles, 1,
VC4_NUM_UPM_HANDLES,
GFP_KERNEL);
if (upm_handle < 0) {
drm_err(drm, "Out of upm_handles\n");
return ret;
}
vc4_state->upm_handle[i] = upm_handle;

refcount = &hvs->upm_refcounts[upm_handle];
refcount_set(&refcount->refcount, 1);
refcount->size = upm_size;

spin_lock_irqsave(&hvs->mm_lock, irqflags);
ret = drm_mm_insert_node_generic(&hvs->upm_mm,
&refcount->upm,
upm_size, HVS_UBM_WORD_SIZE,
0, 0);
spin_unlock_irqrestore(&hvs->mm_lock, irqflags);
if (ret) {
drm_err(drm, "Failed to allocate UPM entry: %d\n", ret);
refcount_dec(&refcount->refcount);
ida_free(&hvs->upm_handles, upm_handle);
return ret;
}
}

ret = ida_alloc_range(&hvs->upm_handles, 1, 32, GFP_KERNEL);
if (ret < 0)
return ret;

vc4_state->upm_handle[i] = ret;

refcount = &hvs->upm_refcounts[upm_handle];
vc4_state->dlist[vc4_state->ptr0_offset[i]] |=
VC4_SET_FIELD(vc4_state->upm[i].start / HVS_UBM_WORD_SIZE,
VC4_SET_FIELD(refcount->upm.start / HVS_UBM_WORD_SIZE,
SCALER6_PTR0_UPM_BASE) |
VC4_SET_FIELD(vc4_state->upm_handle[i] - 1,
SCALER6_PTR0_UPM_HANDLE) |
Expand Down

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