This adds generic fbdev emulation for drivers that supports
dumb buffers which they can export.
All the driver has to do is call drm_fbdev_generic_setup().
Signed-off-by: Noralf Trønnes <noralf@xxxxxxxxxxx>
---
drivers/gpu/drm/drm_fb_helper.c | 255 ++++++++++++++++++++++++++++++++++++++++
include/drm/drm_fb_helper.h | 20 ++++
2 files changed, 275 insertions(+)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index b1124c08b1ed..1954de5b13e0 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -30,6 +30,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/console.h>
+#include <linux/dma-buf.h>
#include <linux/kernel.h>
#include <linux/sysrq.h>
#include <linux/slab.h>
@@ -1995,6 +1996,260 @@ void drm_fb_helper_output_poll_changed(struct drm_device *dev)
}
EXPORT_SYMBOL(drm_fb_helper_output_poll_changed);
+static int drm_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
+{
+ struct drm_fb_helper *fb_helper = info->par;
+
+ return dma_buf_mmap(fb_helper->buffer->dma_buf, vma, 0);
+}
+
+/*
+ * fb_ops.fb_destroy is called by the last put_fb_info() call at the end of
+ * unregister_framebuffer() or fb_release().
+ */
+static void drm_fbdev_fb_destroy(struct fb_info *info)
+{
+ struct drm_fb_helper *fb_helper = info->par;
+ struct fb_ops *fbops = NULL;
+
+ DRM_DEBUG("\n");
+
+ if (fb_helper->fbdev->fbdefio)
+ fbops = fb_helper->fbdev->fbops;
+
+ drm_fb_helper_fini(fb_helper);
+ drm_client_framebuffer_delete(fb_helper->buffer);
+ drm_client_free(fb_helper->client);
+ kfree(fb_helper);
+ kfree(fbops);
+}
+
+static struct fb_ops drm_fbdev_fb_ops = {
+ /*
+ * No need to set owner, this module is already pinned by the driver.
+ * A reference is taken on the driver module in drm_fb_helper_fb_open()
+ * to prevent the driver going away with open fd's.
+ */
+ DRM_FB_HELPER_DEFAULT_OPS,
+ .fb_open = drm_fb_helper_fb_open,
+ .fb_release = drm_fb_helper_fb_release,
+ .fb_destroy = drm_fbdev_fb_destroy,
+ .fb_mmap = drm_fbdev_fb_mmap,
+ .fb_read = drm_fb_helper_sys_read,
+ .fb_write = drm_fb_helper_sys_write,
+ .fb_fillrect = drm_fb_helper_sys_fillrect,
+ .fb_copyarea = drm_fb_helper_sys_copyarea,
+ .fb_imageblit = drm_fb_helper_sys_imageblit,
+};
+
+static struct fb_deferred_io drm_fbdev_defio = {
+ .delay = HZ / 20,
+ .deferred_io = drm_fb_helper_deferred_io,
+};
+
+/* Hack to test tinydrm before converting to vmalloc buffers */
+static int drm_fbdev_cma_deferred_io_mmap(struct fb_info *info,
+ struct vm_area_struct *vma)
+{
+ fb_deferred_io_mmap(info, vma);
+ vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
+
+ return 0;
+}
+
+static int drm_fb_helper_generic_probe(struct drm_fb_helper *fb_helper,
+ struct drm_fb_helper_surface_size *sizes)
+{
+ struct drm_client_dev *client = fb_helper->client;
+ struct drm_display_mode sizes_mode = {
+ .hdisplay = sizes->surface_width,
+ .vdisplay = sizes->surface_height,
+ };
+ struct drm_client_buffer *buffer;
+ struct drm_framebuffer *fb;
+ struct fb_info *fbi;
+ u32 format;
+ int ret;
+
+ DRM_DEBUG_KMS("surface width(%d), height(%d) and bpp(%d)\n",
+ sizes->surface_width, sizes->surface_height,
+ sizes->surface_bpp);
+
+ format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);
+ buffer = drm_client_framebuffer_create(client, &sizes_mode, format);
+ if (IS_ERR(buffer))
+ return PTR_ERR(buffer);
+
+ fb_helper->buffer = buffer;
+ fb_helper->fb = buffer->fb;
+ fb = buffer->fb;
+
+ fbi = drm_fb_helper_alloc_fbi(fb_helper);
+ if (IS_ERR(fbi)) {
+ ret = PTR_ERR(fbi);
+ goto err_free_buffer;
+ }
+
+ fbi->par = fb_helper;
+ fbi->fbops = &drm_fbdev_fb_ops;
+ fbi->screen_size = fb->height * fb->pitches[0];
+ fbi->fix.smem_len = fbi->screen_size;
+ fbi->screen_buffer = buffer->vaddr;
+ strcpy(fbi->fix.id, "DRM emulated");
+
+ drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->format->depth);
+ drm_fb_helper_fill_var(fbi, fb_helper, sizes->fb_width, sizes->fb_height);
+
+ /*
+ * Drivers that set the dirty callback:
+ * - Doesn't use defio:
+ * i915, virtio, rockchip
+ * - defio with vmalloc buffer blitted on the real one:
+ * vmwgfx
+ * - defio is disabled because it doesn't work with shmem:
+ * udl
+ * - defio with special dirty callback for fbdev, uses vmalloc for fbdev:
+ * qxl
+ * - defio with cma buffer, will move to vmalloc buffers:
+ * tinydrm
+ *
+ * TODO:
+ * Maybe add vmalloc shadow buffer support.
+ */
+
+ if (fb->funcs->dirty) {
+ struct fb_ops *fbops;
+
+ /*
+ * fb_deferred_io_cleanup() clears &fbops->fb_mmap so a per
+ * instance version is necessary.
+ */
+ fbops = kzalloc(sizeof(*fbops), GFP_KERNEL);
+ if (!fbops) {
+ ret = -ENOMEM;
+ goto err_fb_info_destroy;
+ }
+
+ *fbops = *fbi->fbops;
+ fbi->fbops = fbops;
+
+ fbi->fbdefio = &drm_fbdev_defio;
+
+ /* Hack so I can test with tinydrm */
+ fbi->fix.smem_start = page_to_phys(virt_to_page(buffer->vaddr));
+
+ fb_deferred_io_init(fbi);
+
+ /* Hack so I can test with tinydrm */
+ fbi->fbops->fb_mmap = drm_fbdev_cma_deferred_io_mmap;
+ }
+
+ return 0;
+
+err_fb_info_destroy:
+ drm_fb_helper_fini(fb_helper);
+err_free_buffer:
+ drm_client_framebuffer_delete(buffer);
+
+ return ret;
+}
+
+static const struct drm_fb_helper_funcs drm_fb_helper_generic_funcs = {
+ .fb_probe = drm_fb_helper_generic_probe,
+};
+
+static int drm_fbdev_client_remove(struct drm_client_dev *client)
+{
+ struct drm_fb_helper *fb_helper = client->private;
+
+ if (!fb_helper->fbdev) {
+ kfree(fb_helper);
+ return 0;
+ }
+
+ unregister_framebuffer(fb_helper->fbdev);
+
+ /*
+ * If userspace is closed the client is now freed by
+ * drm_fbdev_fb_destroy(), otherwise it will be freed on the last close.
+ * Return 1 to tell that freeing is taken care of.
+ */
+
+ return 1;
+}
+
+static int drm_fbdev_client_lastclose(struct drm_client_dev *client)
+{
+ struct drm_fb_helper *fb_helper = client->private;
+
+ drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper);
+
+ return 0;
+}
+
+static int drm_fbdev_client_hotplug(struct drm_client_dev *client)
+{
+ struct drm_fb_helper *fb_helper = client->private;
+
+ if (fb_helper->fbdev)
+ return 0;
+
+ return drm_fb_helper_fbdev_setup(client->dev, fb_helper,
+ &drm_fb_helper_generic_funcs,
+ fb_helper->preferred_bpp, 0);
+}
+
+static const struct drm_client_funcs drm_fbdev_client_funcs = {
+ .name = "fbdev",
+ .remove = drm_fbdev_client_remove,
+ .lastclose = drm_fbdev_client_lastclose,
+ .hotplug = drm_fbdev_client_hotplug,
+};
+
+/**
+ * drm_fb_helper_generic_fbdev_setup() - Setup generic fbdev emulation
+ * @dev: DRM device
+ * @preferred_bpp: Preferred bits per pixel for the device.
+ * @dev->mode_config.preferred_depth is used if this is zero.
+ *
+ * This function sets up generic fbdev emulation for drivers that supports
+ * dumb buffers which can be exported.
+ *
+ * Restore, hotplug events and teardown are all taken care of. Drivers that does
+ * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves.
+ * Simple drivers might use drm_mode_config_helper_suspend().
+ *
+ * Returns:
+ * Zero on success or negative error code on failure.
+ */
+int drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp)
+{
+ struct drm_fb_helper *fb_helper;
+ struct drm_client_dev *client;
+
+ if (!drm_fbdev_emulation)
+ return 0;
+
+ fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
+ if (!fb_helper)
+ return -ENOMEM;
+
+ client = drm_client_new(dev, &drm_fbdev_client_funcs);
+ if (IS_ERR(client)) {
+ kfree(fb_helper);
+ return PTR_ERR(client);
+ }
+
+ client->private = fb_helper;
+ fb_helper->client = client;
+ fb_helper->preferred_bpp = preferred_bpp;
+
+ drm_fbdev_client_hotplug(client);
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_fbdev_generic_setup);
+
/* The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
* but the module doesn't depend on any fb console symbols. At least
* attempt to load fbcon to avoid leaving the system without a usable console.
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index 330983975d5e..711da1747836 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -126,6 +126,20 @@ struct drm_fb_helper {
*/
struct drm_client_display *display;
+ /**
+ * @client:
+ *
+ * DRM client used by the generic fbdev emulation.
+ */
+ struct drm_client_dev *client;
+
+ /**
+ * @buffer:
+ *
+ * Framebuffer used by the generic fbdev emulation.
+ */
+ struct drm_client_buffer *buffer;
+
const struct drm_fb_helper_funcs *funcs;
struct fb_info *fbdev;
u32 pseudo_palette[17];
@@ -219,6 +233,7 @@ struct drm_fb_helper {
.fb_ioctl = drm_fb_helper_ioctl
#ifdef CONFIG_DRM_FBDEV_EMULATION
+int drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp);
void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
const struct drm_fb_helper_funcs *funcs);
int drm_fb_helper_init(struct drm_device *dev,
@@ -297,6 +312,11 @@ void drm_fb_helper_fbdev_teardown(struct drm_device *dev);
void drm_fb_helper_lastclose(struct drm_device *dev);
void drm_fb_helper_output_poll_changed(struct drm_device *dev);
#else
+static inline int
+drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp)
+{
+}
+
static inline void drm_fb_helper_prepare(struct drm_device *dev,
struct drm_fb_helper *helper,
const struct drm_fb_helper_funcs *funcs)
--
2.15.1
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