gallium: Stub support for Asahi + DRM

Copy-paste a pile of winsys code from panfrost and find-and-replace the name to
asahi. This should contain all the glue code needed for asahi+kmsro.

The kernel driver is under way (led by Asahi Lina, not me), but it's not
wred up here. My goal was rather to run shader-db, which expects a
render node, which means drm-shim, which means DRM loader support. With
this patch and a trivial drm-shim, shader-db runs.

In general I am reticent to touch UABI related code when the UABI hasn't been
finalized upstream, or started design at all, hence the RFC. Realistically this
patch assumes the following about the future UABI:

0. It will be a DRM driver. This is nonnegotiable.

1. The render node will be named "asahi". The other reasonable name would be
   "apple", which I'm using for the display controller (not yet upstream, but
   getting close).

2. Display and rendering will be split in the kernel, requiring kmsro in
   userspace, as agreed in past discussions.

   The 3D accelerator (AGX) and the display controller (DCP) are completely
   orthogonal blocks with separate lineages. True, Apple A14 (~= M1) has AGX and
   DCP together, and it seems like all the chips that will get upstream support
   will have this for the forseeable future. Nevertheless, it's a historical
   coincidence. Apple A12 had an AGX block with a pre-DCP Apple display
   controller, which would use a completely different display driver. Older SoCs
   had a PowerVR block with an Apple shader core, with a pre-DCP Apple display
   controller. Even older SoCs had a pure PowerVR block (+ Apple display).

   The AGX and DCP kernel drivers are not expected to share any nontrivial code.
   We don't gain anything by bundling them together. Likewise, the many
   codec blocks are completely orthogonal. This is all standard practice
   for Arm SoCs.

   It is true that AGX has never been used with a non-Apple display
   controller; it is highly unlikely this would change (either by AGX
   licensing out or something like Mali-DP getting licensed in). But
   an extra kmsro user doesn't actually add more complexity to Mesa, so
   shrug.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Eric Engestrom <eric@igalia.com> [meson, ack on gallium]
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15940>

meson.build

@@ -234,7 +234,11 @@ foreach gallium_driver : gallium_drivers
 endforeach
 
 with_gallium = gallium_drivers.length() != 0
-with_gallium_kmsro = with_gallium_v3d or with_gallium_vc4 or with_gallium_etnaviv or with_gallium_panfrost or with_gallium_lima or with_gallium_freedreno
+with_gallium_kmsro = with_gallium_v3d or with_gallium_vc4 or with_gallium_etnaviv or with_gallium_panfrost or with_gallium_lima or with_gallium_freedreno or with_gallium_asahi
+
+if not system_has_kms_drm
+   with_gallium_kmsro = false
+endif
 
 with_dri = false
 if with_gallium and system_has_kms_drm

src/gallium/auxiliary/pipe-loader/pipe_loader_drm.c

@@ -82,6 +82,7 @@ static const struct drm_driver_descriptor *driver_descriptors[] = {
    &v3d_driver_descriptor,
    &vc4_driver_descriptor,
    &panfrost_driver_descriptor,
+   &asahi_driver_descriptor,
    &etnaviv_driver_descriptor,
    &tegra_driver_descriptor,
    &lima_driver_descriptor,

src/gallium/auxiliary/target-helpers/drm_helper.h

@@ -67,6 +67,7 @@ const struct drm_driver_descriptor descriptor_name = {         \
 #undef GALLIUM_ETNAVIV
 #undef GALLIUM_PANFROST
 #undef GALLIUM_LIMA
+#undef GALLIUM_ASAHI
 #endif
 
 #ifdef GALLIUM_I915
@@ -355,6 +356,23 @@ DRM_DRIVER_DESCRIPTOR(panfrost, NULL, 0)
 DRM_DRIVER_DESCRIPTOR_STUB(panfrost)
 #endif
 
+#ifdef GALLIUM_ASAHI
+#include "asahi/drm/asahi_drm_public.h"
+
+static struct pipe_screen *
+pipe_asahi_create_screen(int fd, const struct pipe_screen_config *config)
+{
+   struct pipe_screen *screen;
+
+   screen = asahi_drm_screen_create(fd);
+   return screen ? debug_screen_wrap(screen) : NULL;
+}
+DRM_DRIVER_DESCRIPTOR(asahi, NULL, 0)
+
+#else
+DRM_DRIVER_DESCRIPTOR_STUB(asahi)
+#endif
+
 #ifdef GALLIUM_ETNAVIV
 #include "etnaviv/drm/etnaviv_drm_public.h"
 

src/gallium/auxiliary/target-helpers/drm_helper_public.h

@@ -18,6 +18,7 @@ extern const struct drm_driver_descriptor virtio_gpu_driver_descriptor;
 extern const struct drm_driver_descriptor v3d_driver_descriptor;
 extern const struct drm_driver_descriptor vc4_driver_descriptor;
 extern const struct drm_driver_descriptor panfrost_driver_descriptor;
+extern const struct drm_driver_descriptor asahi_driver_descriptor;
 extern const struct drm_driver_descriptor etnaviv_driver_descriptor;
 extern const struct drm_driver_descriptor tegra_driver_descriptor;
 extern const struct drm_driver_descriptor lima_driver_descriptor;

src/gallium/auxiliary/target-helpers/inline_sw_helper.h

@@ -69,7 +69,7 @@ sw_screen_create_named(struct sw_winsys *winsys, const char *driver)
 
 #if defined(GALLIUM_ASAHI)
    if (screen == NULL && strcmp(driver, "asahi") == 0)
-      screen = agx_screen_create(winsys);
+      screen = agx_screen_create(0, NULL, winsys);
 #endif
 
    return screen ? debug_screen_wrap(screen) : NULL;

src/gallium/auxiliary/target-helpers/sw_helper.h

@@ -73,7 +73,7 @@ sw_screen_create_named(struct sw_winsys *winsys, const struct pipe_screen_config
 
 #if defined(GALLIUM_ASAHI)
    if (screen == NULL && strcmp(driver, "asahi") == 0)
-      screen = agx_screen_create(winsys);
+      screen = agx_screen_create(0, NULL, winsys);
 #endif
 
    return screen;

src/gallium/drivers/asahi/agx_pipe.c

@@ -1155,7 +1155,7 @@ static const struct u_transfer_vtbl transfer_vtbl = {
 };
 
 struct pipe_screen *
-agx_screen_create(struct sw_winsys *winsys)
+agx_screen_create(int fd, struct renderonly *ro, struct sw_winsys *winsys)
 {
    struct agx_screen *agx_screen;
    struct pipe_screen *screen;

src/gallium/drivers/asahi/agx_public.h

@@ -29,7 +29,10 @@ extern "C" {
 
 struct pipe_screen;
 struct sw_winsys;
-struct pipe_screen *agx_screen_create(struct sw_winsys *winsys);
+struct renderonly;
+
+struct pipe_screen *
+agx_screen_create(int fd, struct renderonly *ro, struct sw_winsys *winsys);
 
 #ifdef __cplusplus
 }

src/gallium/drivers/asahi/meson.build

@@ -37,5 +37,5 @@ libasahi = static_library(
 
 driver_asahi = declare_dependency(
   compile_args : '-DGALLIUM_ASAHI',
-  link_with : [libasahi, libasahi_compiler, libasahi_lib, libasahi_layout, libasahi_decode]
+  link_with : [libasahi, libasahiwinsys, libasahi_compiler, libasahi_lib, libasahi_layout, libasahi_decode]
 )

src/gallium/meson.build

@@ -54,6 +54,7 @@ else
   driver_swrast = declare_dependency()
 endif
 if with_gallium_asahi
+  subdir('winsys/asahi/drm')
   subdir('drivers/asahi')
 else
   driver_asahi = declare_dependency()

src/gallium/targets/dri/target.c

@@ -84,6 +84,10 @@ DEFINE_LOADER_DRM_ENTRYPOINT(vc4)
 DEFINE_LOADER_DRM_ENTRYPOINT(panfrost)
 #endif
 
+#if defined(GALLIUM_ASAHI)
+DEFINE_LOADER_DRM_ENTRYPOINT(asahi)
+#endif
+
 #if defined(GALLIUM_ETNAVIV)
 DEFINE_LOADER_DRM_ENTRYPOINT(etnaviv)
 #endif

src/gallium/targets/pipe-loader/meson.build

@@ -48,7 +48,7 @@ pipe_loader_install_dir = join_paths(get_option('libdir'), 'gallium-pipe')
 
 _kmsro_targets = [
    driver_kmsro, driver_v3d, driver_vc4, driver_freedreno, driver_etnaviv,
-   driver_panfrost, driver_lima,
+   driver_panfrost, driver_lima, driver_asahi,
 ]
 
 if with_gallium_v3d

src/gallium/winsys/asahi/drm/asahi_drm_public.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright © 2014 Broadcom
+ * Copyright © 208 Alyssa Rosenzweig
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef __ASAHI_DRM_PUBLIC_H__
+#define __ASAHI_DRM_PUBLIC_H__
+
+#include <stdbool.h>
+
+struct pipe_screen;
+struct renderonly;
+
+struct pipe_screen *asahi_drm_screen_create(int drmFD);
+struct pipe_screen *asahi_drm_screen_create_renderonly(struct renderonly *ro);
+
+#endif /* __ASAHI_DRM_PUBLIC_H__ */

src/gallium/winsys/asahi/drm/asahi_drm_winsys.c

@@ -0,0 +1,49 @@
+/*
+ * Copyright © 2014 Broadcom
+ * Copyright © 208 Alyssa Rosenzweig
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "util/format/u_format.h"
+#include "util/os_file.h"
+#include "util/u_math.h"
+#include "util/u_memory.h"
+
+#include "drm-uapi/drm.h"
+#include "renderonly/renderonly.h"
+#include "asahi_drm_public.h"
+#include "asahi/agx_public.h"
+
+struct pipe_screen *
+asahi_drm_screen_create(int fd)
+{
+   return agx_screen_create(os_dupfd_cloexec(fd), NULL, NULL);
+}
+
+struct pipe_screen *
+asahi_drm_screen_create_renderonly(struct renderonly *ro)
+{
+   return agx_screen_create(os_dupfd_cloexec(ro->gpu_fd), ro, NULL);
+}

src/gallium/winsys/asahi/drm/meson.build

@@ -0,0 +1,30 @@
+# Copyright © 2017 Broadcom
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+libasahiwinsys = static_library(
+  'asahiwinsys',
+  files('asahi_drm_winsys.c'),
+  include_directories : [
+    inc_src, inc_include,
+    inc_gallium, inc_gallium_aux, inc_gallium_drivers,
+  ],
+  gnu_symbol_visibility : 'hidden',
+  dependencies: dep_libdrm,
+)

src/gallium/winsys/kmsro/drm/kmsro_drm_winsys.c

@@ -32,6 +32,7 @@
 #include "freedreno/drm/freedreno_drm_public.h"
 #include "panfrost/drm/panfrost_drm_public.h"
 #include "lima/drm/lima_drm_public.h"
+#include "asahi/drm/asahi_drm_public.h"
 #include "xf86drm.h"
 
 #include "pipe/p_screen.h"
@@ -136,6 +137,19 @@ struct pipe_screen *kmsro_drm_screen_create(int fd,
    }
 #endif
 
+#if defined(GALLIUM_ASAHI)
+   ro->gpu_fd = drmOpenWithType("asahi", NULL, DRM_NODE_RENDER);
+
+   if (ro->gpu_fd >= 0) {
+      ro->create_for_resource = renderonly_create_kms_dumb_buffer_for_resource;
+      screen = asahi_drm_screen_create_renderonly(ro);
+      if (!screen)
+         goto out_free;
+
+      return screen;
+   }
+#endif
+
    return screen;
 
 out_free:

src/gallium/winsys/kmsro/drm/meson.build

@@ -37,6 +37,9 @@ endif
 if with_gallium_panfrost
   kmsro_c_args += '-DGALLIUM_PANFROST'
 endif
+if with_gallium_asahi
+  kmsro_c_args += '-DGALLIUM_ASAHI'
+endif
 
 libkmsrowinsys = static_library(
   'kmsrowinsys',