gallium: add flag PIPE_TRANSFER_MAP_PERMANENTLY

Please see the diff for further info.

This paves the way for moving user buffer uploads out of drivers and should
allow to clean up the mess in u_upload_mgr in the meantime.

For now only allowed for buffers on r300 and r600.

Acked-by: Christian König <deathsimple@vodafone.de>

src/gallium/drivers/i915/i915_resource_buffer.c

@@ -68,8 +68,13 @@ i915_get_transfer(struct pipe_context *pipe,
                   const struct pipe_box *box)
 {
    struct i915_context *i915 = i915_context(pipe);
-   struct pipe_transfer *transfer = util_slab_alloc(&i915->transfer_pool);
+   struct pipe_transfer *transfer;
 
+   if (usage & PIPE_TRANSFER_MAP_PERMANENTLY) {
+      return NULL;
+   }
+
+   transfer = util_slab_alloc(&i915->transfer_pool);
    if (transfer == NULL)
       return NULL;
 

src/gallium/drivers/i915/i915_resource_texture.c

@@ -720,9 +720,14 @@ i915_texture_get_transfer(struct pipe_context *pipe,
 {
    struct i915_context *i915 = i915_context(pipe);
    struct i915_texture *tex = i915_texture(resource);
-   struct i915_transfer *transfer = util_slab_alloc(&i915->texture_transfer_pool);
+   struct i915_transfer *transfer;
    boolean use_staging_texture = FALSE;
 
+   if (usage & PIPE_TRANSFER_MAP_PERMANENTLY) {
+      return NULL;
+   }
+
+   transfer = util_slab_alloc(&i915->texture_transfer_pool);
    if (transfer == NULL)
       return NULL;
 

src/gallium/drivers/llvmpipe/lp_texture.c

@@ -587,6 +587,10 @@ llvmpipe_get_transfer(struct pipe_context *pipe,
    assert(resource);
    assert(level <= resource->last_level);
 
+   if (usage & PIPE_TRANSFER_MAP_PERMANENTLY) {
+      return NULL;
+   }
+
    /*
     * Transfers, like other pipe operations, must happen in order, so flush the
     * context if necessary.

src/gallium/drivers/nouveau/nouveau_buffer.c

@@ -172,7 +172,13 @@ nouveau_buffer_transfer_get(struct pipe_context *pipe,
 {
    struct nv04_resource *buf = nv04_resource(resource);
    struct nouveau_context *nv = nouveau_context(pipe);
-   struct nouveau_transfer *xfr = CALLOC_STRUCT(nouveau_transfer);
+   struct nouveau_transfer *xfr;
+
+   if (usage & PIPE_TRANSFER_MAP_PERMANENTLY) {
+      return NULL;
+   }
+
+   xfr = CALLOC_STRUCT(nouveau_transfer);
    if (!xfr)
       return NULL;
 

src/gallium/drivers/nv50/nv50_transfer.c

@@ -243,7 +243,7 @@ nv50_miptree_transfer_new(struct pipe_context *pctx,
    uint32_t size;
    int ret;
 
-   if (usage & PIPE_TRANSFER_MAP_DIRECTLY)
+   if (usage & (PIPE_TRANSFER_MAP_DIRECTLY | PIPE_TRANSFER_MAP_PERMANENTLY))
       return NULL;
 
    tx = CALLOC_STRUCT(nv50_transfer);

src/gallium/drivers/nvc0/nvc0_transfer.c

@@ -243,7 +243,7 @@ nvc0_miptree_transfer_new(struct pipe_context *pctx,
    uint32_t size;
    int ret;
 
-   if (usage & PIPE_TRANSFER_MAP_DIRECTLY)
+   if (usage & (PIPE_TRANSFER_MAP_DIRECTLY | PIPE_TRANSFER_MAP_PERMANENTLY))
       return NULL;
 
    tx = CALLOC_STRUCT(nvc0_transfer);

src/gallium/drivers/nvfx/nvfx_transfer.c

@@ -26,6 +26,9 @@ nvfx_transfer_new(struct pipe_context *pipe,
 		  unsigned usage,
 		  const struct pipe_box *box)
 {
+        if (usage & PIPE_TRANSFER_MAP_PERMANENTLY) {
+                return NULL;
+        }
         if((usage & (PIPE_TRANSFER_UNSYNCHRONIZED | PIPE_TRANSFER_DONTBLOCK)) == PIPE_TRANSFER_DONTBLOCK)
         {
                 struct nouveau_bo* bo = ((struct nvfx_resource*)pt)->bo;

src/gallium/drivers/r300/r300_transfer.c

@@ -89,6 +89,10 @@ r300_texture_get_transfer(struct pipe_context *ctx,
     struct pipe_resource base;
     boolean referenced_cs, referenced_hw;
 
+    if (usage & (PIPE_TRANSFER_MAP_DIRECTLY | PIPE_TRANSFER_MAP_PERMANENTLY)) {
+        return NULL;
+    }
+
     referenced_cs =
         r300->rws->cs_is_buffer_referenced(r300->cs, tex->cs_buf);
     if (referenced_cs) {

src/gallium/drivers/r600/r600_texture.c

@@ -630,6 +630,10 @@ struct pipe_transfer* r600_texture_get_transfer(struct pipe_context *ctx,
 	int r;
 	boolean use_staging_texture = FALSE;
 
+	if (usage & PIPE_TRANSFER_MAP_PERMANENTLY) {
+	   return NULL;
+	}
+
 	/* We cannot map a tiled texture directly because the data is
 	 * in a different order, therefore we do detiling using a blit.
 	 *

src/gallium/drivers/svga/svga_resource_buffer.c

@@ -74,6 +74,10 @@ svga_buffer_get_transfer(struct pipe_context *pipe,
    struct svga_buffer *sbuf = svga_buffer(resource);
    struct pipe_transfer *transfer;
 
+   if (usage & PIPE_TRANSFER_MAP_PERMANENTLY) {
+      return NULL;
+   }
+
    transfer = CALLOC_STRUCT(pipe_transfer);
    if (transfer == NULL) {
       return NULL;

src/gallium/drivers/svga/svga_resource_texture.c

@@ -259,7 +259,7 @@ svga_texture_get_transfer(struct pipe_context *pipe,
    unsigned nblocksy = util_format_get_nblocksy(texture->format, box->height);
 
    /* We can't map texture storage directly */
-   if (usage & PIPE_TRANSFER_MAP_DIRECTLY)
+   if (usage & (PIPE_TRANSFER_MAP_DIRECTLY | PIPE_TRANSFER_MAP_PERMANENTLY))
       return NULL;
 
    assert(box->depth == 1);

src/gallium/include/pipe/p_defines.h

@@ -225,6 +225,22 @@ enum pipe_transfer_usage {
     */
    PIPE_TRANSFER_MAP_DIRECTLY = (1 << 2),
 
+   /**
+    * The transfer should map the resource storage directly and the GPU should
+    * be able to see what the CPU has written. Such a storage may stay mapped
+    * while issuing draw commands which use it. The only allowed usage is
+    * non-overlapping writes which are suballocated out of a big buffer.
+    * The minimum allowed alignment of suballocations is 256 bytes (this is
+    * a subject to change).
+    * The flag is intended to be used to avoid mapping and unmapping
+    * resources repeatedly when doing uploads and draws intermixed.
+    *
+    * The driver may return NULL if that isn't possible, and the state
+    * tracker needs to cope with that and use an alternative path
+    * without this flag.
+    */
+   PIPE_TRANSFER_MAP_PERMANENTLY = (1 << 3),
+
    /**
     * Discards the memory within the mapped region.
     *