gpu: nvgpu: bitmap allocator for comptags

Restore comptags to be bitmap-allocated, like they were before we had
the buddy allocator.

The new buddy allocator introduced by
e99aa2485f8992eabe3556f3ebcb57bdc8ad91ff (originally
6ab2e0c49cb79ca68d2f83f1d4610783d2eaa79b) is fine for the big VAs, but
unsuitable for the small compbit store.

This commit reverts partially the combination of the above commit and
also one after it, 86fc7ec9a05999bea8de320840b962db3ee11410, that fixed
a bug which is not present when using a bitmap. With a bitmap allocator,
pruning the extra allocation necessary for user-mapped mode is possible,
so that is also restored.

The original generic bitmap allocator is not restored; instead, a
comptag-only allocator is introduced.

Bug 200145635

Change-Id: I87f3a911826a801124cfd21e44857dfab1c3f378
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/837180
(cherry picked from commit 5a504aeb54f3e89e6561932971158a397157b3f2)
Reviewed-on: http://git-master/r/839742
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gr_gk20a.h b/drivers/gpu/nvgpu/gk20a/gr_gk20a.h
index 94d7c811..c7100182 100644
--- a/drivers/gpu/nvgpu/gk20a/gr_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/gr_gk20a.h
@@ -281,7 +281,13 @@ struct gr_gk20a {
 
         u32 max_comptag_mem; /* max memory size (MB) for comptag */
         struct compbit_store_desc compbit_store;
-        struct gk20a_allocator comp_tags;
+        struct gk20a_comptag_allocator {
+                struct mutex lock;
+                /* this bitmap starts at ctag 1. 0th cannot be taken */
+                unsigned long *bitmap;
+                /* size of bitmap, not max ctags, so one less */
+                unsigned long size;
+        } comp_tags;
 
         struct gr_zcull_gk20a zcull;
 
@@ -400,6 +406,10 @@ int gk20a_init_gr_support(struct gk20a *g);
 int gk20a_enable_gr_hw(struct gk20a *g);
 int gk20a_gr_reset(struct gk20a *g);
 void gk20a_gr_wait_initialized(struct gk20a *g);
+/* real size here, but first (ctag 0) isn't used */
+int gk20a_comptag_allocator_init(struct gk20a_comptag_allocator *allocator,
+                unsigned long size);
+void gk20a_comptag_allocator_destroy(struct gk20a_comptag_allocator *allocator);
 
 int gk20a_init_gr_channel(struct channel_gk20a *ch_gk20a);