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// SPDX-License-Identifier: MIT
#include <linux/moduleparam.h>
#include <linux/vmalloc.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_drv.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_gem.h>
#include <drm/drm_print.h>
#include <drm/drm_fbdev_generic.h>
/* @user: 1=userspace, 0=fbcon */
static int drm_fbdev_generic_fb_open(struct fb_info *info, int user)
{
struct drm_fb_helper *fb_helper = info->par;
/* No need to take a ref for fbcon because it unbinds on unregister */
if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
return -ENODEV;
return 0;
}
static int drm_fbdev_generic_fb_release(struct fb_info *info, int user)
{
struct drm_fb_helper *fb_helper = info->par;
if (user)
module_put(fb_helper->dev->driver->fops->owner);
return 0;
}
FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(drm_fbdev_generic,
drm_fb_helper_damage_range,
drm_fb_helper_damage_area);
static void drm_fbdev_generic_fb_destroy(struct fb_info *info)
{
struct drm_fb_helper *fb_helper = info->par;
void *shadow = info->screen_buffer;
if (!fb_helper->dev)
return;
fb_deferred_io_cleanup(info);
drm_fb_helper_fini(fb_helper);
vfree(shadow);
drm_client_framebuffer_delete(fb_helper->buffer);
drm_client_release(&fb_helper->client);
drm_fb_helper_unprepare(fb_helper);
kfree(fb_helper);
}
static const struct fb_ops drm_fbdev_generic_fb_ops = {
.owner = THIS_MODULE,
.fb_open = drm_fbdev_generic_fb_open,
.fb_release = drm_fbdev_generic_fb_release,
FB_DEFAULT_DEFERRED_OPS(drm_fbdev_generic),
DRM_FB_HELPER_DEFAULT_OPS,
.fb_destroy = drm_fbdev_generic_fb_destroy,
};
/*
* This function uses the client API to create a framebuffer backed by a dumb buffer.
*/
static int drm_fbdev_generic_helper_fb_probe(struct drm_fb_helper *fb_helper,
struct drm_fb_helper_surface_size *sizes)
{
struct drm_client_dev *client = &fb_helper->client;
struct drm_device *dev = fb_helper->dev;
struct drm_client_buffer *buffer;
struct fb_info *info;
size_t screen_size;
void *screen_buffer;
u32 format;
int ret;
drm_dbg_kms(dev, "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->surface_width,
sizes->surface_height, format);
if (IS_ERR(buffer))
return PTR_ERR(buffer);
fb_helper->buffer = buffer;
fb_helper->fb = buffer->fb;
screen_size = buffer->gem->size;
screen_buffer = vzalloc(screen_size);
if (!screen_buffer) {
ret = -ENOMEM;
goto err_drm_client_framebuffer_delete;
}
info = drm_fb_helper_alloc_info(fb_helper);
if (IS_ERR(info)) {
ret = PTR_ERR(info);
goto err_vfree;
}
drm_fb_helper_fill_info(info, fb_helper, sizes);
info->fbops = &drm_fbdev_generic_fb_ops;
/* screen */
info->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST;
info->screen_buffer = screen_buffer;
info->fix.smem_start = page_to_phys(vmalloc_to_page(info->screen_buffer));
info->fix.smem_len = screen_size;
/* deferred I/O */
fb_helper->fbdefio.delay = HZ / 20;
fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
info->fbdefio = &fb_helper->fbdefio;
ret = fb_deferred_io_init(info);
if (ret)
goto err_drm_fb_helper_release_info;
return 0;
err_drm_fb_helper_release_info:
drm_fb_helper_release_info(fb_helper);
err_vfree:
vfree(screen_buffer);
err_drm_client_framebuffer_delete:
fb_helper->fb = NULL;
fb_helper->buffer = NULL;
drm_client_framebuffer_delete(buffer);
return ret;
}
static void drm_fbdev_generic_damage_blit_real(struct drm_fb_helper *fb_helper,
struct drm_clip_rect *clip,
struct iosys_map *dst)
{
struct drm_framebuffer *fb = fb_helper->fb;
size_t offset = clip->y1 * fb->pitches[0];
size_t len = clip->x2 - clip->x1;
unsigned int y;
void *src;
switch (drm_format_info_bpp(fb->format, 0)) {
case 1:
offset += clip->x1 / 8;
len = DIV_ROUND_UP(len + clip->x1 % 8, 8);
break;
case 2:
offset += clip->x1 / 4;
len = DIV_ROUND_UP(len + clip->x1 % 4, 4);
break;
case 4:
offset += clip->x1 / 2;
len = DIV_ROUND_UP(len + clip->x1 % 2, 2);
break;
default:
offset += clip->x1 * fb->format->cpp[0];
len *= fb->format->cpp[0];
break;
}
src = fb_helper->info->screen_buffer + offset;
iosys_map_incr(dst, offset); /* go to first pixel within clip rect */
for (y = clip->y1; y < clip->y2; y++) {
iosys_map_memcpy_to(dst, 0, src, len);
iosys_map_incr(dst, fb->pitches[0]);
src += fb->pitches[0];
}
}
static int drm_fbdev_generic_damage_blit(struct drm_fb_helper *fb_helper,
struct drm_clip_rect *clip)
{
struct drm_client_buffer *buffer = fb_helper->buffer;
struct iosys_map map, dst;
int ret;
/*
* We have to pin the client buffer to its current location while
* flushing the shadow buffer. In the general case, concurrent
* modesetting operations could try to move the buffer and would
* fail. The modeset has to be serialized by acquiring the reservation
* object of the underlying BO here.
*
* For fbdev emulation, we only have to protect against fbdev modeset
* operations. Nothing else will involve the client buffer's BO. So it
* is sufficient to acquire struct drm_fb_helper.lock here.
*/
mutex_lock(&fb_helper->lock);
ret = drm_client_buffer_vmap_local(buffer, &map);
if (ret)
goto out;
dst = map;
drm_fbdev_generic_damage_blit_real(fb_helper, clip, &dst);
drm_client_buffer_vunmap_local(buffer);
out:
mutex_unlock(&fb_helper->lock);
return ret;
}
static int drm_fbdev_generic_helper_fb_dirty(struct drm_fb_helper *helper,
struct drm_clip_rect *clip)
{
struct drm_device *dev = helper->dev;
int ret;
/* Call damage handlers only if necessary */
if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
return 0;
ret = drm_fbdev_generic_damage_blit(helper, clip);
if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret))
return ret;
if (helper->fb->funcs->dirty) {
ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
return ret;
}
return 0;
}
static const struct drm_fb_helper_funcs drm_fbdev_generic_helper_funcs = {
.fb_probe = drm_fbdev_generic_helper_fb_probe,
.fb_dirty = drm_fbdev_generic_helper_fb_dirty,
};
static void drm_fbdev_generic_client_unregister(struct drm_client_dev *client)
{
struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
if (fb_helper->info) {
drm_fb_helper_unregister_info(fb_helper);
} else {
drm_client_release(&fb_helper->client);
drm_fb_helper_unprepare(fb_helper);
kfree(fb_helper);
}
}
static int drm_fbdev_generic_client_restore(struct drm_client_dev *client)
{
drm_fb_helper_lastclose(client->dev);
return 0;
}
static int drm_fbdev_generic_client_hotplug(struct drm_client_dev *client)
{
struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
struct drm_device *dev = client->dev;
int ret;
if (dev->fb_helper)
return drm_fb_helper_hotplug_event(dev->fb_helper);
ret = drm_fb_helper_init(dev, fb_helper);
if (ret)
goto err_drm_err;
if (!drm_drv_uses_atomic_modeset(dev))
drm_helper_disable_unused_functions(dev);
ret = drm_fb_helper_initial_config(fb_helper);
if (ret)
goto err_drm_fb_helper_fini;
return 0;
err_drm_fb_helper_fini:
drm_fb_helper_fini(fb_helper);
err_drm_err:
drm_err(dev, "fbdev: Failed to setup generic emulation (ret=%d)\n", ret);
return ret;
}
static const struct drm_client_funcs drm_fbdev_generic_client_funcs = {
.owner = THIS_MODULE,
.unregister = drm_fbdev_generic_client_unregister,
.restore = drm_fbdev_generic_client_restore,
.hotplug = drm_fbdev_generic_client_hotplug,
};
/**
* drm_fbdev_generic_setup() - Setup generic fbdev emulation
* @dev: DRM device
* @preferred_bpp: Preferred bits per pixel for the device.
*
* This function sets up generic fbdev emulation for drivers that supports
* dumb buffers with a virtual address and that can be mmap'ed.
* drm_fbdev_generic_setup() shall be called after the DRM driver registered
* the new DRM device with drm_dev_register().
*
* Restore, hotplug events and teardown are all taken care of. Drivers that do
* suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves.
* Simple drivers might use drm_mode_config_helper_suspend().
*
* In order to provide fixed mmap-able memory ranges, generic fbdev emulation
* uses a shadow buffer in system memory. The implementation blits the shadow
* fbdev buffer onto the real buffer in regular intervals.
*
* This function is safe to call even when there are no connectors present.
* Setup will be retried on the next hotplug event.
*
* The fbdev is destroyed by drm_dev_unregister().
*/
void drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp)
{
struct drm_fb_helper *fb_helper;
int ret;
drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
if (!fb_helper)
return;
drm_fb_helper_prepare(dev, fb_helper, preferred_bpp, &drm_fbdev_generic_helper_funcs);
ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_generic_client_funcs);
if (ret) {
drm_err(dev, "Failed to register client: %d\n", ret);
goto err_drm_client_init;
}
drm_client_register(&fb_helper->client);
return;
err_drm_client_init:
drm_fb_helper_unprepare(fb_helper);
kfree(fb_helper);
return;
}
EXPORT_SYMBOL(drm_fbdev_generic_setup);
|