Preparations for adding wlr capturing

1 files changed, 226 insertions, 0 deletions

diff --git a/capture_kms.c b/capture_kms.c
new file mode 100644
index 0000000..52742e8
--- /dev/null
+++ b/capture_kms.c
@@ -0,0 +1,226 @@
+/*
+ * Copyright (C) 2023 Mikhail Burakov. This file is part of streamer.
+ *
+ * streamer is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * streamer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with streamer.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "capture_kms.h"
+
+#include <assert.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/timerfd.h>
+#include <time.h>
+#include <unistd.h>
+#include <xf86drm.h>
+
+#include "gpu.h"
+#include "toolbox/utils.h"
+
+static const int kCapturePeriod = 1000000000 / 60;
+
+struct CaptureContextKms {
+  struct IoMuxer* io_muxer;
+  struct GpuContext* gpu_context;
+  const struct CaptureContextCallbacks* callbacks;
+  void* user;
+
+  int drm_fd;
+  uint32_t crtc_id;
+  int timer_fd;
+};
+
+static int OpenAnyModule(void) {
+  static const char* const modules[] = {
+      "i915",
+      "amdgpu",
+  };
+  for (size_t i = 0; i < LENGTH(modules); i++) {
+    int drm_fd = drmOpen(modules[i], NULL);
+    if (drm_fd >= 0) return drm_fd;
+    LOG("Failed to open %s (%s)", modules[i], strerror(errno));
+  }
+  return -1;
+}
+
+static bool GetCrtcFb(int drm_fd, uint32_t crtc_id,
+                      struct drm_mode_fb_cmd2* drm_mode_fb_cmd2) {
+  struct drm_mode_crtc drm_mode_crtc = {
+      .crtc_id = crtc_id,
+  };
+  if (drmIoctl(drm_fd, DRM_IOCTL_MODE_GETCRTC, &drm_mode_crtc)) {
+    LOG("Failed to get crtc %u (%s)", crtc_id, strerror(errno));
+    return false;
+  }
+  if (!drm_mode_crtc.fb_id) {
+    LOG("Crtc %u has no framebuffer", crtc_id);
+    return false;
+  }
+
+  struct drm_mode_fb_cmd2 result = {
+      .fb_id = drm_mode_crtc.fb_id,
+  };
+  if (drmIoctl(drm_fd, DRM_IOCTL_MODE_GETFB2, &result)) {
+    LOG("Failed to get framebuffer %u (%s)", drm_mode_crtc.fb_id,
+        strerror(errno));
+    return false;
+  }
+  if (!result.handles[0]) {
+    LOG("Framebuffer %u has no handles", drm_mode_crtc.fb_id);
+    return false;
+  }
+
+  if (drm_mode_fb_cmd2) *drm_mode_fb_cmd2 = result;
+  return true;
+}
+
+struct CaptureContextKms* CaptureContextKmsCreate(
+    struct GpuContext* gpu_context,
+    const struct CaptureContextCallbacks* callbacks, void* user) {
+  struct CaptureContextKms* capture_context =
+      malloc(sizeof(struct CaptureContextKms));
+  if (!capture_context) {
+    LOG("Failed to allocate capture context (%s)", strerror(errno));
+    return NULL;
+  }
+  *capture_context = (struct CaptureContextKms){
+      .gpu_context = gpu_context,
+      .callbacks = callbacks,
+      .user = user,
+      .drm_fd = -1,
+      .timer_fd = -1,
+  };
+
+  capture_context->drm_fd = OpenAnyModule();
+  if (capture_context->drm_fd == -1) {
+    LOG("Failed to open any module");
+    goto rollback_capture_context;
+  }
+
+  uint32_t crtc_ids[16];
+  struct drm_mode_card_res drm_mode_card_res = {
+      .crtc_id_ptr = (uintptr_t)crtc_ids,
+      .count_crtcs = LENGTH(crtc_ids),
+  };
+  if (drmIoctl(capture_context->drm_fd, DRM_IOCTL_MODE_GETRESOURCES,
+               &drm_mode_card_res)) {
+    LOG("Failed to get drm mode resources (%s)", strerror(errno));
+    goto rollback_drm_fd;
+  }
+  for (size_t i = 0; i < drm_mode_card_res.count_crtcs; i++) {
+    if (GetCrtcFb(capture_context->drm_fd, crtc_ids[i], NULL)) {
+      LOG("Capturing crtc %u", crtc_ids[i]);
+      capture_context->crtc_id = crtc_ids[i];
+      break;
+    }
+  }
+  if (!capture_context->crtc_id) {
+    LOG("Nothing to capture");
+    goto rollback_drm_fd;
+  }
+
+  capture_context->timer_fd = timerfd_create(CLOCK_MONOTONIC, 0);
+  if (capture_context->timer_fd == -1) {
+    LOG("Failed to create timer (%s)", strerror(errno));
+    goto rollback_drm_fd;
+  }
+  static const struct itimerspec kTimerSpec = {
+      .it_interval.tv_nsec = kCapturePeriod,
+      .it_value.tv_nsec = kCapturePeriod,
+  };
+  if (timerfd_settime(capture_context->timer_fd, 0, &kTimerSpec, NULL)) {
+    LOG("Failed to arm timer (%s)", strerror(errno));
+    goto rollback_timer_fd;
+  }
+  return capture_context;
+
+rollback_timer_fd:
+  close(capture_context->timer_fd);
+rollback_drm_fd:
+  drmClose(capture_context->drm_fd);
+rollback_capture_context:
+  free(capture_context);
+  return NULL;
+}
+
+int CaptureContextKmsGetEventsFd(struct CaptureContextKms* capture_context) {
+  return capture_context->timer_fd;
+}
+
+bool CaptureContextKmsProcessEvents(struct CaptureContextKms* capture_context) {
+  uint64_t expirations;
+  if (read(capture_context->timer_fd, &expirations, sizeof(expirations)) !=
+      sizeof(expirations)) {
+    LOG("Failed to read timer expirations (%s)", strerror(errno));
+    return false;
+  }
+
+  struct drm_mode_fb_cmd2 drm_mode_fb_cmd2;
+  if (!GetCrtcFb(capture_context->drm_fd, capture_context->crtc_id,
+                 &drm_mode_fb_cmd2)) {
+    return false;
+  }
+
+  struct GpuFramePlane planes[] = {
+      {.dmabuf_fd = -1},
+      {.dmabuf_fd = -1},
+      {.dmabuf_fd = -1},
+      {.dmabuf_fd = -1},
+  };
+  static_assert(LENGTH(planes) == LENGTH(drm_mode_fb_cmd2.handles),
+                "Suspicious drm_mode_fb_cmd2 structure");
+
+  size_t nplanes = 0;
+  for (; nplanes < LENGTH(planes); nplanes++) {
+    if (!drm_mode_fb_cmd2.handles[nplanes]) break;
+    int status = drmPrimeHandleToFD(capture_context->drm_fd,
+                                    drm_mode_fb_cmd2.handles[nplanes], 0,
+                                    &planes[nplanes].dmabuf_fd);
+    if (status) {
+      LOG("Failed to get dmabuf fd (%d)", status);
+      goto release_planes;
+    }
+    planes[nplanes].offset = drm_mode_fb_cmd2.offsets[nplanes];
+    planes[nplanes].pitch = drm_mode_fb_cmd2.pitches[nplanes];
+    planes[nplanes].modifier = drm_mode_fb_cmd2.modifier[nplanes];
+  }
+
+  struct GpuFrame* gpu_frame = GpuContextCreateFrame(
+      capture_context->gpu_context, drm_mode_fb_cmd2.width,
+      drm_mode_fb_cmd2.height, drm_mode_fb_cmd2.pixel_format, nplanes, planes);
+  if (!gpu_frame) {
+    LOG("Failed to create gpu frame");
+    goto release_planes;
+  }
+
+  // mburakov: Capture context might get destroyed in callback.
+  struct GpuContext* gpu_context = capture_context->gpu_context;
+  capture_context->callbacks->OnFrameReady(capture_context->user, gpu_frame);
+  GpuContextDestroyFrame(gpu_context, gpu_frame);
+  return true;
+
+release_planes:
+  CloseUniqueFds((int[]){planes[0].dmabuf_fd, planes[1].dmabuf_fd,
+                         planes[2].dmabuf_fd, planes[3].dmabuf_fd});
+  return false;
+}
+
+void CaptureContextKmsDestroy(struct CaptureContextKms* capture_context) {
+  close(capture_context->timer_fd);
+  drmClose(capture_context->drm_fd);
+  free(capture_context);
+}