drm_fb: implement drm fb backend

Largely mechanical copying of the drm code into the new fb_ops_t
abstraction.  Dormant for now.

1 files changed, 157 insertions, 0 deletions

diff --git a/src/drm_fb.c b/src/drm_fb.c
new file mode 100644
index 0000000..99169de
--- /dev/null
+++ b/src/drm_fb.c
@@ -0,0 +1,157 @@
+#include <fcntl.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <xf86drm.h>
+#include <xf86drmMode.h>
+
+#include "fb.h"
+#include "util.h"
+
+
+/* drm fb backend, everything drm-specific in rototiller resides here. */
+
+typedef struct drm_fb_t {
+	int			drm_fd;
+	uint32_t		crtc_id;
+	uint32_t		*connectors;
+	int			n_connectors;
+	drmModeModeInfoPtr	mode;
+} drm_fb_t;
+
+typedef struct drm_fb_page_t drm_fb_page_t;
+
+struct drm_fb_page_t {
+	uint32_t		*mmap;
+	size_t			mmap_size;
+	uint32_t		drm_dumb_handle;
+	uint32_t		drm_fb_id;
+};
+
+
+drm_fb_t * drm_fb_new(int drm_fd, uint32_t crtc_id, uint32_t *connectors, int n_connectors, drmModeModeInfoPtr mode)
+{
+	drm_fb_t	*c;
+
+	c = calloc(1, sizeof(drm_fb_t));
+	if (!c)
+		return NULL;
+
+	c->drm_fd = drm_fd;
+	c->crtc_id = crtc_id;
+	c->connectors = connectors;
+	c->n_connectors = n_connectors;
+	c->mode = mode;
+
+	return c;
+}
+
+
+void drm_fb_free(drm_fb_t *context)
+{
+	free(context);
+}
+
+
+static int drm_fb_acquire(void *context, void *page)
+{
+	drm_fb_t	*c = context;
+	drm_fb_page_t	*p = page;
+
+	return drmModeSetCrtc(c->drm_fd, c->crtc_id, p->drm_fb_id, 0, 0, c->connectors, c->n_connectors, c->mode);
+}
+
+
+static void drm_fb_release(void *context)
+{
+	/* TODO restore the existing mode @ last acquire? */
+}
+
+
+static void * drm_fb_page_alloc(void *context, fb_page_t *res_page)
+{
+	struct drm_mode_create_dumb	create_dumb = { .bpp = 32 };
+	struct drm_mode_map_dumb	map_dumb = {};
+	uint32_t			*map, fb_id;
+	drm_fb_t			*c = context;
+	drm_fb_page_t			*p;
+
+	p = calloc(1, sizeof(drm_fb_page_t));
+	if (!p)
+		return NULL;
+
+	create_dumb.width = c->mode->hdisplay;
+	create_dumb.height = c->mode->vdisplay;
+
+	pexit_if(ioctl(c->drm_fd, DRM_IOCTL_MODE_CREATE_DUMB, &create_dumb) < 0,
+		"unable to create dumb buffer");
+
+	map_dumb.handle = create_dumb.handle;
+	pexit_if(ioctl(c->drm_fd, DRM_IOCTL_MODE_MAP_DUMB, &map_dumb) < 0,
+		"unable to prepare dumb buffer for mmap");
+	pexit_if(!(map = mmap(NULL, create_dumb.size, PROT_READ|PROT_WRITE, MAP_SHARED, c->drm_fd, map_dumb.offset)),
+		"unable to mmap dumb buffer");
+	pexit_if(drmModeAddFB(c->drm_fd, c->mode->hdisplay, c->mode->vdisplay, 24, 32, create_dumb.pitch, create_dumb.handle, &fb_id) < 0,
+		"unable to add dumb buffer");
+
+	p->mmap = map;
+	p->mmap_size = create_dumb.size;
+	p->drm_dumb_handle = map_dumb.handle;
+	p->drm_fb_id = fb_id;
+
+	res_page->fragment.buf = map;
+	res_page->fragment.width = c->mode->hdisplay;
+	res_page->fragment.frame_width = c->mode->hdisplay;
+	res_page->fragment.height = c->mode->vdisplay;
+	res_page->fragment.frame_height = c->mode->vdisplay;
+	res_page->fragment.stride = create_dumb.pitch - (c->mode->hdisplay * 4);
+
+	return p;
+}
+
+
+static int drm_fb_page_free(void *context, void *page)
+{
+	struct drm_mode_destroy_dumb	destroy_dumb = {};
+	drm_fb_t			*c = context;
+	drm_fb_page_t			*p = page;
+
+	drmModeRmFB(c->drm_fd, p->drm_fb_id);
+	munmap(p->mmap, p->mmap_size);
+
+	destroy_dumb.handle = p->drm_dumb_handle;
+	ioctl(c->drm_fd, DRM_IOCTL_MODE_DESTROY_DUMB, &destroy_dumb); // XXX: errors?
+
+	free(p);
+
+	return 0;
+}
+
+
+static int drm_fb_page_flip(void *context, void *page)
+{
+	drmEventContext	drm_ev_ctx = {
+				.version = DRM_EVENT_CONTEXT_VERSION,
+				.vblank_handler = NULL,
+				.page_flip_handler = NULL
+			};
+	drm_fb_t	*c = context;
+	drm_fb_page_t	*p = page;
+
+	if (drmModePageFlip(c->drm_fd, c->crtc_id, p->drm_fb_id, DRM_MODE_PAGE_FLIP_EVENT, NULL) < 0)
+		return -1;
+
+	return drmHandleEvent(c->drm_fd, &drm_ev_ctx);
+}
+
+
+fb_ops_t drm_fb_ops = {
+	.acquire = drm_fb_acquire,
+	.release = drm_fb_release,
+	.page_alloc = drm_fb_page_alloc,
+	.page_free = drm_fb_page_free,
+	.page_flip = drm_fb_page_flip
+};