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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_print.h>
#include <drm/drm_fbdev_generic.h>
static bool drm_fbdev_use_shadow_fb(struct drm_fb_helper *fb_helper)
{
struct drm_device *dev = fb_helper->dev;
struct drm_framebuffer *fb = fb_helper->fb;
return dev->mode_config.prefer_shadow_fbdev ||
dev->mode_config.prefer_shadow ||
fb->funcs->dirty;
}
/* @user: 1=userspace, 0=fbcon */
static int drm_fbdev_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_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;
}
static void drm_fbdev_cleanup(struct drm_fb_helper *fb_helper)
{
struct fb_info *fbi = fb_helper->info;
void *shadow = NULL;
if (!fb_helper->dev)
return;
if (fbi) {
if (fbi->fbdefio)
fb_deferred_io_cleanup(fbi);
if (drm_fbdev_use_shadow_fb(fb_helper))
shadow = fbi->screen_buffer;
}
drm_fb_helper_fini(fb_helper);
if (shadow)
vfree(shadow);
else if (fb_helper->buffer)
drm_client_buffer_vunmap(fb_helper->buffer);
drm_client_framebuffer_delete(fb_helper->buffer);
}
static void drm_fbdev_release(struct drm_fb_helper *fb_helper)
{
drm_fbdev_cleanup(fb_helper);
drm_client_release(&fb_helper->client);
kfree(fb_helper);
}
/*
* 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)
{
drm_fbdev_release(info->par);
}
static int drm_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
struct drm_fb_helper *fb_helper = info->par;
if (drm_fbdev_use_shadow_fb(fb_helper))
return fb_deferred_io_mmap(info, vma);
else if (fb_helper->dev->driver->gem_prime_mmap)
return fb_helper->dev->driver->gem_prime_mmap(fb_helper->buffer->gem, vma);
else
return -ENODEV;
}
static bool drm_fbdev_use_iomem(struct fb_info *info)
{
struct drm_fb_helper *fb_helper = info->par;
struct drm_client_buffer *buffer = fb_helper->buffer;
return !drm_fbdev_use_shadow_fb(fb_helper) && buffer->map.is_iomem;
}
static ssize_t drm_fbdev_fb_read(struct fb_info *info, char __user *buf,
size_t count, loff_t *ppos)
{
ssize_t ret;
if (drm_fbdev_use_iomem(info))
ret = drm_fb_helper_cfb_read(info, buf, count, ppos);
else
ret = drm_fb_helper_sys_read(info, buf, count, ppos);
return ret;
}
static ssize_t drm_fbdev_fb_write(struct fb_info *info, const char __user *buf,
size_t count, loff_t *ppos)
{
ssize_t ret;
if (drm_fbdev_use_iomem(info))
ret = drm_fb_helper_cfb_write(info, buf, count, ppos);
else
ret = drm_fb_helper_sys_write(info, buf, count, ppos);
return ret;
}
static void drm_fbdev_fb_fillrect(struct fb_info *info,
const struct fb_fillrect *rect)
{
if (drm_fbdev_use_iomem(info))
drm_fb_helper_cfb_fillrect(info, rect);
else
drm_fb_helper_sys_fillrect(info, rect);
}
static void drm_fbdev_fb_copyarea(struct fb_info *info,
const struct fb_copyarea *area)
{
if (drm_fbdev_use_iomem(info))
drm_fb_helper_cfb_copyarea(info, area);
else
drm_fb_helper_sys_copyarea(info, area);
}
static void drm_fbdev_fb_imageblit(struct fb_info *info,
const struct fb_image *image)
{
if (drm_fbdev_use_iomem(info))
drm_fb_helper_cfb_imageblit(info, image);
else
drm_fb_helper_sys_imageblit(info, image);
}
static const struct fb_ops drm_fbdev_fb_ops = {
.owner = THIS_MODULE,
DRM_FB_HELPER_DEFAULT_OPS,
.fb_open = drm_fbdev_fb_open,
.fb_release = drm_fbdev_fb_release,
.fb_destroy = drm_fbdev_fb_destroy,
.fb_mmap = drm_fbdev_fb_mmap,
.fb_read = drm_fbdev_fb_read,
.fb_write = drm_fbdev_fb_write,
.fb_fillrect = drm_fbdev_fb_fillrect,
.fb_copyarea = drm_fbdev_fb_copyarea,
.fb_imageblit = drm_fbdev_fb_imageblit,
};
static struct fb_deferred_io drm_fbdev_defio = {
.delay = HZ / 20,
.deferred_io = drm_fb_helper_deferred_io,
};
/*
* This function uses the client API to create a framebuffer backed by a dumb buffer.
*/
static int drm_fbdev_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 drm_framebuffer *fb;
struct fb_info *fbi;
u32 format;
struct iosys_map map;
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;
fb = buffer->fb;
fbi = drm_fb_helper_alloc_info(fb_helper);
if (IS_ERR(fbi))
return PTR_ERR(fbi);
fbi->fbops = &drm_fbdev_fb_ops;
fbi->screen_size = sizes->surface_height * fb->pitches[0];
fbi->fix.smem_len = fbi->screen_size;
fbi->flags = FBINFO_DEFAULT;
drm_fb_helper_fill_info(fbi, fb_helper, sizes);
if (drm_fbdev_use_shadow_fb(fb_helper)) {
fbi->screen_buffer = vzalloc(fbi->screen_size);
if (!fbi->screen_buffer)
return -ENOMEM;
fbi->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST;
fbi->fbdefio = &drm_fbdev_defio;
fb_deferred_io_init(fbi);
} else {
/* buffer is mapped for HW framebuffer */
ret = drm_client_buffer_vmap(fb_helper->buffer, &map);
if (ret)
return ret;
if (map.is_iomem) {
fbi->screen_base = map.vaddr_iomem;
} else {
fbi->screen_buffer = map.vaddr;
fbi->flags |= FBINFO_VIRTFB;
}
/*
* Shamelessly leak the physical address to user-space. As
* page_to_phys() is undefined for I/O memory, warn in this
* case.
*/
#if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)
if (fb_helper->hint_leak_smem_start && fbi->fix.smem_start == 0 &&
!drm_WARN_ON_ONCE(dev, map.is_iomem))
fbi->fix.smem_start =
page_to_phys(virt_to_page(fbi->screen_buffer));
#endif
}
return 0;
}
static void drm_fbdev_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_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(buffer, &map);
if (ret)
goto out;
dst = map;
drm_fbdev_damage_blit_real(fb_helper, clip, &dst);
drm_client_buffer_vunmap(buffer);
out:
mutex_unlock(&fb_helper->lock);
return ret;
}
static int drm_fbdev_fb_dirty(struct drm_fb_helper *helper, struct drm_clip_rect *clip)
{
struct drm_device *dev = helper->dev;
int ret;
if (!drm_fbdev_use_shadow_fb(helper))
return 0;
/* Call damage handlers only if necessary */
if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
return 0;
if (helper->buffer) {
ret = drm_fbdev_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_fb_helper_generic_funcs = {
.fb_probe = drm_fbdev_fb_probe,
.fb_dirty = drm_fbdev_fb_dirty,
};
static void drm_fbdev_client_unregister(struct drm_client_dev *client)
{
struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
if (fb_helper->info)
/* drm_fbdev_fb_destroy() takes care of cleanup */
drm_fb_helper_unregister_info(fb_helper);
else
drm_fbdev_release(fb_helper);
}
static int drm_fbdev_client_restore(struct drm_client_dev *client)
{
drm_fb_helper_lastclose(client->dev);
return 0;
}
static int drm_fbdev_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);
drm_fb_helper_prepare(dev, fb_helper, &drm_fb_helper_generic_funcs);
ret = drm_fb_helper_init(dev, fb_helper);
if (ret)
goto err;
if (!drm_drv_uses_atomic_modeset(dev))
drm_helper_disable_unused_functions(dev);
ret = drm_fb_helper_initial_config(fb_helper, fb_helper->preferred_bpp);
if (ret)
goto err_cleanup;
return 0;
err_cleanup:
drm_fbdev_cleanup(fb_helper);
err:
fb_helper->dev = NULL;
fb_helper->info = NULL;
drm_err(dev, "fbdev: Failed to setup generic emulation (ret=%d)\n", ret);
return ret;
}
static const struct drm_client_funcs drm_fbdev_client_funcs = {
.owner = THIS_MODULE,
.unregister = drm_fbdev_client_unregister,
.restore = drm_fbdev_client_restore,
.hotplug = drm_fbdev_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().
*
* Drivers that set the dirty callback on their framebuffer will get a shadow
* fbdev buffer that is blitted onto the real buffer. This is done in order to
* make deferred I/O work with all kinds of buffers. A shadow buffer can be
* requested explicitly by setting struct drm_mode_config.prefer_shadow or
* struct drm_mode_config.prefer_shadow_fbdev to true beforehand. This is
* required to use generic fbdev emulation with SHMEM helpers.
*
* 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;
ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_client_funcs);
if (ret) {
kfree(fb_helper);
drm_err(dev, "Failed to register client: %d\n", ret);
return;
}
/*
* Pick a preferred bpp of 32 if no value has been given. This
* will select XRGB8888 for the framebuffer formats. All drivers
* have to support XRGB8888 for backwards compatibility with legacy
* userspace, so it's the safe choice here.
*
* TODO: Replace struct drm_mode_config.preferred_depth and this
* bpp value with a preferred format that is given as struct
* drm_format_info. Then derive all other values from the
* format.
*/
if (!preferred_bpp)
preferred_bpp = 32;
fb_helper->preferred_bpp = preferred_bpp;
ret = drm_fbdev_client_hotplug(&fb_helper->client);
if (ret)
drm_dbg_kms(dev, "client hotplug ret=%d\n", ret);
drm_client_register(&fb_helper->client);
}
EXPORT_SYMBOL(drm_fbdev_generic_setup);
|