asahi: Add a shared library interface for decode

Add a simple API so that decode can be used as a shared library by the
Python hypervisor. Note that this is not thread-safe. If we ever want to
use this in other contexts with thread safety, it will need a refactor
(along with the core decode code anyway).

Signed-off-by: Asahi Lina <lina@asahilina.net>
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24258>

src/asahi/lib/decode.c

@@ -28,6 +28,8 @@ struct drm_asahi_params_global {
    int num_clusters_total;
 };
 
+struct libagxdecode_config lib_config;
+
 UNUSED static const char *agx_alloc_types[AGX_NUM_ALLOC] = {"mem", "map",
                                                             "cmd"};
 
@@ -213,6 +215,9 @@ __agxdecode_fetch_gpu_mem(const struct agx_bo *mem, uint64_t gpu_va,
                           size_t size, void *buf, int line,
                           const char *filename)
 {
+   if (lib_config.read_gpu_mem)
+      return lib_config.read_gpu_mem(gpu_va, size, buf);
+
    if (!mem)
       mem = agxdecode_find_mapped_gpu_mem_containing(gpu_va);
 
@@ -282,10 +287,14 @@ agxdecode_stateful(uint64_t va, const char *label, decode_cmd decoder,
                    bool verbose, decoder_params *params, void *data)
 {
    uint8_t buf[1024];
-   struct agx_bo *alloc = agxdecode_find_mapped_gpu_mem_containing(va);
-   assert(alloc != NULL && "nonexistent object");
-   fprintf(agxdecode_dump_stream, "%s (%" PRIx64 ", handle %u)\n", label, va,
-           alloc->handle);
+   if (!lib_config.read_gpu_mem) {
+      struct agx_bo *alloc = agxdecode_find_mapped_gpu_mem_containing(va);
+      assert(alloc != NULL && "nonexistent object");
+      fprintf(agxdecode_dump_stream, "%s (%" PRIx64 ", handle %u)\n", label, va,
+              alloc->handle);
+   } else {
+      fprintf(agxdecode_dump_stream, "%s (%" PRIx64 ")\n", label, va);
+   }
    fflush(agxdecode_dump_stream);
 
    int len = agxdecode_fetch_gpu_array(va, buf);
@@ -608,13 +617,17 @@ agxdecode_vdm(const uint8_t *map, uint64_t *link, bool verbose,
       agx_unpack(agxdecode_dump_stream, map, PPP_STATE, cmd);
 
       uint64_t address = (((uint64_t)cmd.pointer_hi) << 32) | cmd.pointer_lo;
-      struct agx_bo *mem = agxdecode_find_mapped_gpu_mem_containing(address);
 
-      if (mem)
-         agxdecode_record(address, cmd.size_words * 4, verbose, params);
-      else
-         DUMP_UNPACKED(PPP_STATE, cmd, "Non-existent record (XXX)\n");
+      if (!lib_config.read_gpu_mem) {
+         struct agx_bo *mem = agxdecode_find_mapped_gpu_mem_containing(address);
 
+         if (!mem) {
+            DUMP_UNPACKED(PPP_STATE, cmd, "Non-existent record (XXX)\n");
+            return AGX_PPP_STATE_LENGTH;
+         }
+      }
+
+      agxdecode_record(address, cmd.size_words * 4, verbose, params);
       return AGX_PPP_STATE_LENGTH;
    }
 
@@ -951,3 +964,44 @@ agxdecode_close(void)
 {
    agxdecode_dump_file_close();
 }
+
+static ssize_t
+libagxdecode_writer(void *cookie, const char *buffer, size_t size)
+{
+   return lib_config.stream_write(buffer, size);
+}
+
+static cookie_io_functions_t funcs = {.write = libagxdecode_writer};
+
+static decoder_params lib_params;
+
+void
+libagxdecode_init(struct libagxdecode_config *config)
+{
+   lib_config = *config;
+   agxdecode_dump_stream = fopencookie(NULL, "w", funcs);
+
+   chip_id_to_params(&lib_params, config->chip_id);
+}
+
+void
+libagxdecode_vdm(uint64_t addr, const char *label, bool verbose)
+{
+   agxdecode_stateful(addr, label, agxdecode_vdm, verbose, &lib_params, NULL);
+}
+
+void
+libagxdecode_cdm(uint64_t addr, const char *label, bool verbose)
+{
+   agxdecode_stateful(addr, label, agxdecode_cdm, verbose, &lib_params, NULL);
+}
+void
+libagxdecode_usc(uint64_t addr, const char *label, bool verbose)
+{
+   agxdecode_stateful(addr, label, agxdecode_usc, verbose, &lib_params, NULL);
+}
+void
+libagxdecode_shutdown(void)
+{
+   agxdecode_dump_file_close();
+}

src/asahi/lib/decode.h

@@ -8,6 +8,7 @@
 #ifndef __AGX_DECODE_H__
 #define __AGX_DECODE_H__
 
+#include <sys/types.h>
 #include "agx_bo.h"
 
 void agxdecode_next_frame(void);
@@ -25,4 +26,16 @@ void agxdecode_dump_mappings(unsigned map_index);
 
 void agxdecode_track_free(struct agx_bo *bo);
 
+struct libagxdecode_config {
+   uint32_t chip_id;
+   size_t (*read_gpu_mem)(uint64_t addr, size_t size, void *data);
+   ssize_t (*stream_write)(const char *buffer, size_t size);
+};
+
+void libagxdecode_init(struct libagxdecode_config *config);
+void libagxdecode_vdm(uint64_t addr, const char *label, bool verbose);
+void libagxdecode_cdm(uint64_t addr, const char *label, bool verbose);
+void libagxdecode_usc(uint64_t addr, const char *label, bool verbose);
+void libagxdecode_shutdown(void);
+
 #endif /* __AGX_DECODE_H__ */

src/asahi/lib/meson.build

@@ -48,6 +48,15 @@ libasahi_decode = static_library(
   build_by_default : false,
 )
 
+libasahi_decode_shared = shared_library(
+  'asahi_decode',
+  [libasahi_decode_files, agx_pack],
+  include_directories : [inc_include, inc_src, inc_mapi, inc_mesa, inc_gallium, inc_gallium_aux, inc_asahi],
+  dependencies : [dep_valgrind, idep_mesautil],
+  c_args : [no_override_init_args],
+  build_by_default : with_tools.contains('asahi'),
+)
+
 libasahi_lib = static_library(
   'asahi_lib',
   [libasahi_lib_files, agx_pack],