panvk: add PANVK_DEBUG(category) to simplify debug control

In general, the debug flags are served once per proc invocation. So we
can make panvk debug flags global and clean up the existing codes in the
next change. Meanwhile, this changes improves branch prediction on user
builds and logs the enabled debug options when startup is used.

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37752>

src/panfrost/vulkan/panvk_instance.c

@@ -13,6 +13,7 @@
 #include "util/driconf.h"
 #include "util/mesa-sha1.h"
 #include "util/os_misc.h"
+#include "util/u_call_once.h"
 
 #include "vk_alloc.h"
 #include "vk_log.h"
@@ -46,6 +47,30 @@ static const struct debug_control panvk_debug_options[] = {
    {"force_blackhole", PANVK_DEBUG_FORCE_BLACKHOLE},
    {NULL, 0}};
 
+uint64_t panvk_debug;
+
+static void
+panvk_debug_init_once(void)
+{
+   panvk_debug =
+      parse_debug_string(os_get_option("PANVK_DEBUG"), panvk_debug_options);
+}
+
+static void
+panvk_debug_init(void)
+{
+   static once_flag once = ONCE_FLAG_INIT;
+   call_once(&once, panvk_debug_init_once);
+
+   /* log per VkInstance creation */
+   if (PANVK_DEBUG(STARTUP)) {
+      char debug_string[256];
+      dump_debug_control_string(debug_string, sizeof(debug_string),
+                                panvk_debug_options, panvk_debug);
+      mesa_logi("panvk_debug: %s", debug_string);
+   }
+}
+
 VKAPI_ATTR VkResult VKAPI_CALL
 panvk_EnumerateInstanceVersion(uint32_t *pApiVersion)
 {
@@ -200,6 +225,8 @@ panvk_CreateInstance(const VkInstanceCreateInfo *pCreateInfo,
 
    assert(pCreateInfo->sType == VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO);
 
+   panvk_debug_init();
+
    const struct build_id_note *note =
       build_id_find_nhdr_for_addr(panvk_CreateInstance);
    if (!note) {

src/panfrost/vulkan/panvk_instance.h

@@ -13,6 +13,8 @@
 
 #include "lib/kmod/pan_kmod.h"
 
+#define PANVK_DEBUG(category) (unlikely(panvk_debug & PANVK_DEBUG_##category))
+
 enum panvk_debug_flags {
    PANVK_DEBUG_STARTUP = 1 << 0,
    PANVK_DEBUG_NIR = 1 << 1,
@@ -29,6 +31,8 @@ enum panvk_debug_flags {
    PANVK_DEBUG_FORCE_BLACKHOLE = 1 << 12,
 };
 
+extern uint64_t panvk_debug;
+
 #if defined(VK_USE_PLATFORM_WAYLAND_KHR) || \
     defined(VK_USE_PLATFORM_XCB_KHR) || \
     defined(VK_USE_PLATFORM_XLIB_KHR) || \