diff options
Diffstat (limited to 'drivers/gpu/drm/drm_fb_dma_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_fb_dma_helper.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_fb_dma_helper.c b/drivers/gpu/drm/drm_fb_dma_helper.c new file mode 100644 index 000000000000..fd71969d2fb1 --- /dev/null +++ b/drivers/gpu/drm/drm_fb_dma_helper.c @@ -0,0 +1,197 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * drm kms/fb dma helper functions + * + * Copyright (C) 2012 Analog Devices Inc. + * Author: Lars-Peter Clausen <lars@metafoo.de> + * + * Based on udl_fbdev.c + * Copyright (C) 2012 Red Hat + */ + +#include <drm/drm_damage_helper.h> +#include <drm/drm_fb_dma_helper.h> +#include <drm/drm_fourcc.h> +#include <drm/drm_framebuffer.h> +#include <drm/drm_gem_dma_helper.h> +#include <drm/drm_gem_framebuffer_helper.h> +#include <drm/drm_panic.h> +#include <drm/drm_plane.h> + +#include <linux/dma-mapping.h> +#include <linux/export.h> +#include <linux/module.h> + +/** + * DOC: framebuffer dma helper functions + * + * Provides helper functions for creating a DMA-contiguous framebuffer. + * + * Depending on the platform, the buffers may be physically non-contiguous and + * mapped through an IOMMU or a similar mechanism, or allocated from + * physically-contiguous memory (using, for instance, CMA or a pool of memory + * reserved at early boot). This is handled behind the scenes by the DMA mapping + * API. + * + * drm_gem_fb_create() is used in the &drm_mode_config_funcs.fb_create + * callback function to create a DMA-contiguous framebuffer. + */ + +/** + * drm_fb_dma_get_gem_obj() - Get DMA GEM object for framebuffer + * @fb: The framebuffer + * @plane: Which plane + * + * Return the DMA GEM object for given framebuffer. + * + * This function will usually be called from the CRTC callback functions. + */ +struct drm_gem_dma_object *drm_fb_dma_get_gem_obj(struct drm_framebuffer *fb, + unsigned int plane) +{ + struct drm_gem_object *gem; + + gem = drm_gem_fb_get_obj(fb, plane); + if (!gem) + return NULL; + + return to_drm_gem_dma_obj(gem); +} +EXPORT_SYMBOL_GPL(drm_fb_dma_get_gem_obj); + +/** + * drm_fb_dma_get_gem_addr() - Get DMA (bus) address for framebuffer, for pixel + * formats where values are grouped in blocks this will get you the beginning of + * the block + * @fb: The framebuffer + * @state: Which state of drm plane + * @plane: Which plane + * Return the DMA GEM address for given framebuffer. + * + * This function will usually be called from the PLANE callback functions. + */ +dma_addr_t drm_fb_dma_get_gem_addr(struct drm_framebuffer *fb, + struct drm_plane_state *state, + unsigned int plane) +{ + struct drm_gem_dma_object *obj; + dma_addr_t dma_addr; + u8 h_div = 1, v_div = 1; + u32 block_w = drm_format_info_block_width(fb->format, plane); + u32 block_h = drm_format_info_block_height(fb->format, plane); + u32 block_size = fb->format->char_per_block[plane]; + u32 sample_x; + u32 sample_y; + u32 block_start_y; + u32 num_hblocks; + + obj = drm_fb_dma_get_gem_obj(fb, plane); + if (!obj) + return 0; + + dma_addr = obj->dma_addr + fb->offsets[plane]; + + if (plane > 0) { + h_div = fb->format->hsub; + v_div = fb->format->vsub; + } + + sample_x = (state->src_x >> 16) / h_div; + sample_y = (state->src_y >> 16) / v_div; + block_start_y = (sample_y / block_h) * block_h; + num_hblocks = sample_x / block_w; + + dma_addr += fb->pitches[plane] * block_start_y; + dma_addr += block_size * num_hblocks; + + return dma_addr; +} +EXPORT_SYMBOL_GPL(drm_fb_dma_get_gem_addr); + +/** + * drm_fb_dma_sync_non_coherent - Sync GEM object to non-coherent backing + * memory + * @drm: DRM device + * @old_state: Old plane state + * @state: New plane state + * + * This function can be used by drivers that use damage clips and have + * DMA GEM objects backed by non-coherent memory. Calling this function + * in a plane's .atomic_update ensures that all the data in the backing + * memory have been written to RAM. + */ +void drm_fb_dma_sync_non_coherent(struct drm_device *drm, + struct drm_plane_state *old_state, + struct drm_plane_state *state) +{ + const struct drm_format_info *finfo = state->fb->format; + struct drm_atomic_helper_damage_iter iter; + const struct drm_gem_dma_object *dma_obj; + unsigned int offset, i; + struct drm_rect clip; + dma_addr_t daddr; + size_t nb_bytes; + + for (i = 0; i < finfo->num_planes; i++) { + dma_obj = drm_fb_dma_get_gem_obj(state->fb, i); + if (!dma_obj->map_noncoherent) + continue; + + daddr = drm_fb_dma_get_gem_addr(state->fb, state, i); + drm_atomic_helper_damage_iter_init(&iter, old_state, state); + + drm_atomic_for_each_plane_damage(&iter, &clip) { + /* Ignore x1/x2 values, invalidate complete lines */ + offset = clip.y1 * state->fb->pitches[i]; + + nb_bytes = (clip.y2 - clip.y1) * state->fb->pitches[i]; + dma_sync_single_for_device(drm->dev, daddr + offset, + nb_bytes, DMA_TO_DEVICE); + } + } +} +EXPORT_SYMBOL_GPL(drm_fb_dma_sync_non_coherent); + +/** + * drm_fb_dma_get_scanout_buffer - Provide a scanout buffer in case of panic + * @plane: DRM primary plane + * @sb: scanout buffer for the panic handler + * Returns: 0 or negative error code + * + * Generic get_scanout_buffer() implementation, for drivers that uses the + * drm_fb_dma_helper. It won't call vmap in the panic context, so the driver + * should make sure the primary plane is vmapped, otherwise the panic screen + * won't get displayed. + */ +int drm_fb_dma_get_scanout_buffer(struct drm_plane *plane, + struct drm_scanout_buffer *sb) +{ + struct drm_gem_dma_object *dma_obj; + struct drm_framebuffer *fb; + + if (!plane->state || !plane->state->fb) + return -EINVAL; + + fb = plane->state->fb; + /* Only support linear modifier */ + if (fb->modifier != DRM_FORMAT_MOD_LINEAR) + return -ENODEV; + + dma_obj = drm_fb_dma_get_gem_obj(fb, 0); + + /* Buffer should be accessible from the CPU */ + if (drm_gem_is_imported(&dma_obj->base)) + return -ENODEV; + + /* Buffer should be already mapped to CPU */ + if (!dma_obj->vaddr) + return -ENODEV; + + iosys_map_set_vaddr(&sb->map[0], dma_obj->vaddr); + sb->format = fb->format; + sb->height = fb->height; + sb->width = fb->width; + sb->pitch[0] = fb->pitches[0]; + return 0; +} +EXPORT_SYMBOL(drm_fb_dma_get_scanout_buffer); |