freedreno: Add seqno helper

It is a pretty common pattern to allocate a non-zero sequence # for
lightweight checking if an object is the same, changed, for use in cache
keys, etc.  (And also pretty common to forget to handle the rollover
zero case.)  Add a helper for this.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21274>

src/freedreno/common/freedreno_common.h

@@ -24,6 +24,7 @@
 #ifndef FREEDRENO_COMMON_H_
 #define FREEDRENO_COMMON_H_
 
+#include "util/u_atomic.h"
 
 /**
  * Helper macro to get around c++ being cranky about an enum that is a bitmask
@@ -56,4 +57,31 @@
 
 #define BIT(bit) BITFIELD64_BIT(bit)
 
+/**
+ * Helper for allocating sequence #s where zero is a non-valid seqno
+ */
+typedef struct {
+   uint32_t counter;
+} seqno_t;
+
+static inline uint32_t
+seqno_next(seqno_t *seq)
+{
+   uint32_t n;
+   do {
+      n = p_atomic_inc_return(&seq->counter);
+   } while (n == 0);
+   return n;
+}
+
+static inline uint16_t
+seqno_next_u16(seqno_t *seq)
+{
+   uint16_t n;
+   do {
+      n = p_atomic_inc_return(&seq->counter);
+   } while (n == 0);
+   return n;
+}
+
 #endif /* FREEDRENO_COMMON_H_ */

src/gallium/drivers/freedreno/a6xx/fd6_context.h

@@ -124,7 +124,7 @@ struct fd6_context {
    struct hash_table *bcolor_cache;
    struct fd_bo *bcolor_mem;
 
-   uint16_t tex_seqno;
+   seqno_t tex_seqno;
    struct hash_table *tex_cache;
    bool tex_cache_needs_invalidate;
 

src/gallium/drivers/freedreno/a6xx/fd6_texture.c

@@ -263,7 +263,7 @@ fd6_sampler_state_create(struct pipe_context *pctx,
       return NULL;
 
    so->base = *cso;
-   so->seqno = ++fd6_context(ctx)->tex_seqno;
+   so->seqno = seqno_next_u16(&fd6_context(ctx)->tex_seqno);
 
    if (cso->min_mip_filter == PIPE_TEX_MIPFILTER_LINEAR)
       miplinear = true;
@@ -395,7 +395,7 @@ fd6_sampler_view_update(struct fd_context *ctx,
       format = rsc->b.b.format;
    }
 
-   so->seqno = ++fd6_context(ctx)->tex_seqno;
+   so->seqno = seqno_next_u16(&fd6_context(ctx)->tex_seqno);
    so->ptr1 = rsc;
    so->rsc_seqno = rsc->seqno;
 

src/gallium/drivers/freedreno/freedreno_batch_cache.c

@@ -430,7 +430,7 @@ alloc_batch_locked(struct fd_batch_cache *cache, struct fd_context *ctx,
    if (!batch)
       return NULL;
 
-   batch->seqno = cache->cnt++;
+   batch->seqno = seqno_next(&cache->cnt);
    batch->idx = idx;
    cache->batch_mask |= (1 << idx);
 

src/gallium/drivers/freedreno/freedreno_batch_cache.h

@@ -40,7 +40,7 @@ struct hash_table;
 
 struct fd_batch_cache {
    struct hash_table *ht;
-   unsigned cnt;
+   seqno_t cnt;
 
    /* set of active batches.. there is an upper limit on the number of
     * in-flight batches, for two reasons:

src/gallium/drivers/freedreno/freedreno_context.c

@@ -705,7 +705,7 @@ fd_context_init(struct fd_context *ctx, struct pipe_screen *pscreen,
    list_inithead(&ctx->acc_active_queries);
 
    fd_screen_lock(ctx->screen);
-   ctx->seqno = ++screen->ctx_seqno;
+   ctx->seqno = seqno_next_u16(&screen->ctx_seqno);
    list_add(&ctx->node, &ctx->screen->context_list);
    fd_screen_unlock(ctx->screen);
 

src/gallium/drivers/freedreno/freedreno_resource.c

@@ -182,7 +182,7 @@ fd_resource_set_bo(struct fd_resource *rsc, struct fd_bo *bo)
    struct fd_screen *screen = fd_screen(rsc->b.b.screen);
 
    rsc->bo = bo;
-   rsc->seqno = p_atomic_inc_return(&screen->rsc_seqno);
+   rsc->seqno = seqno_next_u16(&screen->rsc_seqno);
 }
 
 int
@@ -310,7 +310,7 @@ fd_replace_buffer_storage(struct pipe_context *pctx, struct pipe_resource *pdst,
    fd_resource_tracking_reference(&dst->track, src->track);
    src->is_replacement = true;
 
-   dst->seqno = p_atomic_inc_return(&ctx->screen->rsc_seqno);
+   dst->seqno = seqno_next_u16(&ctx->screen->rsc_seqno);
 
    fd_screen_unlock(ctx->screen);
 }
@@ -461,7 +461,7 @@ fd_try_shadow_resource(struct fd_context *ctx, struct fd_resource *rsc,
    rsc->needs_ubwc_clear = temp;
 
    swap(rsc->layout, shadow->layout);
-   rsc->seqno = p_atomic_inc_return(&ctx->screen->rsc_seqno);
+   rsc->seqno = seqno_next_u16(&ctx->screen->rsc_seqno);
 
    /* at this point, the newly created shadow buffer is not referenced
     * by any batches, but the existing rsc (probably) is.  We need to

src/gallium/drivers/freedreno/freedreno_screen.h

@@ -139,8 +139,8 @@ struct fd_screen {
 
    bool reorder;
 
-   uint16_t rsc_seqno;
-   uint16_t ctx_seqno;
+   seqno_t rsc_seqno;
+   seqno_t ctx_seqno;
    struct util_idalloc_mt buffer_ids;
 
    unsigned num_supported_modifiers;