v3dv: implement VK_EXT_4444_formats

Because these formats are introduced trough an extension, their
enum values are exceedingly large and we cannot use them to index
directly into the format table we had for core formats. Instead,
we put these in a separate table and we always use the
VK_ENUM_OFFSET helper to index into these tables.

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14533>

docs/features.txt

@@ -510,7 +510,7 @@ Khronos extensions that are not part of any Vulkan version:
   VK_KHR_xcb_surface                                    DONE (anv, lvp, radv, tu, v3dv, vn)
   VK_KHR_xlib_surface                                   DONE (anv, lvp, radv, tu, v3dv, vn)
   VK_KHR_zero_initialize_workgroup_memory               DONE (anv, radv)
-  VK_EXT_4444_formats                                   DONE (anv, lvp, radv, tu)
+  VK_EXT_4444_formats                                   DONE (anv, lvp, radv, tu, v3dv)
   VK_EXT_buffer_device_address                          DONE (radv)
   VK_EXT_calibrated_timestamps                          DONE (anv, lvp, radv)
   VK_EXT_color_write_enable                             DONE (anv, lvp, radv, v3dv)

src/broadcom/vulkan/v3dv_device.c

@@ -144,6 +144,7 @@ get_device_extensions(const struct v3dv_physical_device *device,
       .KHR_incremental_present             = true,
 #endif
       .KHR_variable_pointers               = true,
+      .EXT_4444_formats                    = true,
       .EXT_color_write_enable              = true,
       .EXT_custom_border_color             = true,
       .EXT_external_memory_dma_buf         = true,
@@ -1093,6 +1094,14 @@ v3dv_GetPhysicalDeviceFeatures2(VkPhysicalDevice physicalDevice,
 
    vk_foreach_struct(ext, pFeatures->pNext) {
       switch (ext->sType) {
+      case VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_4444_FORMATS_FEATURES_EXT: {
+         VkPhysicalDevice4444FormatsFeaturesEXT *features =
+            (VkPhysicalDevice4444FormatsFeaturesEXT *)ext;
+         features->formatA4R4G4B4 = true;
+         features->formatA4B4G4R4 = true;
+         break;
+      }
+
       case VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CUSTOM_BORDER_COLOR_FEATURES_EXT: {
          VkPhysicalDeviceCustomBorderColorFeaturesEXT *features =
             (VkPhysicalDeviceCustomBorderColorFeaturesEXT *)ext;

src/broadcom/vulkan/v3dvx_formats.c

@@ -26,6 +26,7 @@
 #include "broadcom/cle/v3dx_pack.h"
 
 #include "util/format/u_format.h"
+#include "vulkan/util/vk_util.h"
 
 #define SWIZ(x,y,z,w) {   \
    PIPE_SWIZZLE_##x,      \
@@ -35,7 +36,7 @@
 }
 
 #define FORMAT(vk, rt, tex, swiz, return_size, supports_filtering)  \
-   [VK_FORMAT_##vk] = {                                             \
+   [VK_ENUM_OFFSET(VK_FORMAT_##vk)] = {                             \
       true,                                                         \
       V3D_OUTPUT_IMAGE_FORMAT_##rt,                                 \
       TEXTURE_DATA_FORMAT_##tex,                                    \
@@ -57,6 +58,7 @@
 #define SWIZ_XXXX SWIZ(X, X, X, X)
 #define SWIZ_000X SWIZ(0, 0, 0, X)
 #define SWIZ_WXYZ SWIZ(W, X, Y, Z)
+#define SWIZ_WZYX SWIZ(W, Z, Y, X)
 
 /* FIXME: expand format table to describe whether the format is supported
  * for buffer surfaces (texel buffers, vertex buffers, etc).
@@ -196,13 +198,44 @@ static const struct v3dv_format format_table[] = {
    FORMAT(ASTC_12x12_SRGB_BLOCK,      NO,  ASTC_12X12,               SWIZ_XYZW, 16, true),
 };
 
+/**
+ * Vulkan layout for 4444 formats is defined like this:
+ *
+ * Vulkan ABGR4: (LSB) R | G | B | A (MSB)
+ * Vulkan ARGB4: (LSB) B | G | R | A (MSB)
+ *
+ * We map this to the V3D RGB4 texture format, which really, is ABGR4 with
+ * R in the MSB, so:
+ *
+ * V3D ABGR4   : (LSB) A | B | G | R (MSB)
+ *
+ * Which is reversed from Vulkan's ABGR4 layout. So in order to match Vulkan
+ * semantics we need to apply the following swizzles:
+ *
+ * ABGR4: WZYX (reverse)
+ * ARGB4: YZWX (reverse + swap R/B)
+ */
+static const struct v3dv_format format_table_4444[] = {
+   FORMAT(A4B4G4R4_UNORM_PACK16_EXT, ABGR4444, RGBA4, SWIZ_WZYX, 16, true), /* Reverse */
+   FORMAT(A4R4G4B4_UNORM_PACK16_EXT, ABGR4444, RGBA4, SWIZ_YZWX, 16, true), /* Reverse + RB swap */
+};
+
 const struct v3dv_format *
 v3dX(get_format)(VkFormat format)
 {
+   /* Core formats */
    if (format < ARRAY_SIZE(format_table) && format_table[format].supported)
       return &format_table[format];
-   else
+
+   switch (format) {
+   /* VK_EXT_4444_formats */
+   case VK_FORMAT_A4R4G4B4_UNORM_PACK16_EXT:
+   case VK_FORMAT_A4B4G4R4_UNORM_PACK16_EXT:
+      return &format_table_4444[VK_ENUM_OFFSET(format)];
+
+   default:
       return NULL;
+   }
 }
 
 void