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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * drm kms/fb dma helper functions4 *5 * Copyright (C) 2012 Analog Devices Inc.6 * Author: Lars-Peter Clausen <lars@metafoo.de>7 *8 * Based on udl_fbdev.c9 * Copyright (C) 2012 Red Hat10 */11 12#include <drm/drm_damage_helper.h>13#include <drm/drm_fb_dma_helper.h>14#include <drm/drm_fourcc.h>15#include <drm/drm_framebuffer.h>16#include <drm/drm_gem_dma_helper.h>17#include <drm/drm_gem_framebuffer_helper.h>18#include <drm/drm_panic.h>19#include <drm/drm_plane.h>20#include <linux/dma-mapping.h>21#include <linux/module.h>22 23/**24 * DOC: framebuffer dma helper functions25 *26 * Provides helper functions for creating a DMA-contiguous framebuffer.27 *28 * Depending on the platform, the buffers may be physically non-contiguous and29 * mapped through an IOMMU or a similar mechanism, or allocated from30 * physically-contiguous memory (using, for instance, CMA or a pool of memory31 * reserved at early boot). This is handled behind the scenes by the DMA mapping32 * API.33 *34 * drm_gem_fb_create() is used in the &drm_mode_config_funcs.fb_create35 * callback function to create a DMA-contiguous framebuffer.36 */37 38/**39 * drm_fb_dma_get_gem_obj() - Get DMA GEM object for framebuffer40 * @fb: The framebuffer41 * @plane: Which plane42 *43 * Return the DMA GEM object for given framebuffer.44 *45 * This function will usually be called from the CRTC callback functions.46 */47struct drm_gem_dma_object *drm_fb_dma_get_gem_obj(struct drm_framebuffer *fb,48 unsigned int plane)49{50 struct drm_gem_object *gem;51 52 gem = drm_gem_fb_get_obj(fb, plane);53 if (!gem)54 return NULL;55 56 return to_drm_gem_dma_obj(gem);57}58EXPORT_SYMBOL_GPL(drm_fb_dma_get_gem_obj);59 60/**61 * drm_fb_dma_get_gem_addr() - Get DMA (bus) address for framebuffer, for pixel62 * formats where values are grouped in blocks this will get you the beginning of63 * the block64 * @fb: The framebuffer65 * @state: Which state of drm plane66 * @plane: Which plane67 * Return the DMA GEM address for given framebuffer.68 *69 * This function will usually be called from the PLANE callback functions.70 */71dma_addr_t drm_fb_dma_get_gem_addr(struct drm_framebuffer *fb,72 struct drm_plane_state *state,73 unsigned int plane)74{75 struct drm_gem_dma_object *obj;76 dma_addr_t dma_addr;77 u8 h_div = 1, v_div = 1;78 u32 block_w = drm_format_info_block_width(fb->format, plane);79 u32 block_h = drm_format_info_block_height(fb->format, plane);80 u32 block_size = fb->format->char_per_block[plane];81 u32 sample_x;82 u32 sample_y;83 u32 block_start_y;84 u32 num_hblocks;85 86 obj = drm_fb_dma_get_gem_obj(fb, plane);87 if (!obj)88 return 0;89 90 dma_addr = obj->dma_addr + fb->offsets[plane];91 92 if (plane > 0) {93 h_div = fb->format->hsub;94 v_div = fb->format->vsub;95 }96 97 sample_x = (state->src_x >> 16) / h_div;98 sample_y = (state->src_y >> 16) / v_div;99 block_start_y = (sample_y / block_h) * block_h;100 num_hblocks = sample_x / block_w;101 102 dma_addr += fb->pitches[plane] * block_start_y;103 dma_addr += block_size * num_hblocks;104 105 return dma_addr;106}107EXPORT_SYMBOL_GPL(drm_fb_dma_get_gem_addr);108 109/**110 * drm_fb_dma_sync_non_coherent - Sync GEM object to non-coherent backing111 * memory112 * @drm: DRM device113 * @old_state: Old plane state114 * @state: New plane state115 *116 * This function can be used by drivers that use damage clips and have117 * DMA GEM objects backed by non-coherent memory. Calling this function118 * in a plane's .atomic_update ensures that all the data in the backing119 * memory have been written to RAM.120 */121void drm_fb_dma_sync_non_coherent(struct drm_device *drm,122 struct drm_plane_state *old_state,123 struct drm_plane_state *state)124{125 const struct drm_format_info *finfo = state->fb->format;126 struct drm_atomic_helper_damage_iter iter;127 const struct drm_gem_dma_object *dma_obj;128 unsigned int offset, i;129 struct drm_rect clip;130 dma_addr_t daddr;131 size_t nb_bytes;132 133 for (i = 0; i < finfo->num_planes; i++) {134 dma_obj = drm_fb_dma_get_gem_obj(state->fb, i);135 if (!dma_obj->map_noncoherent)136 continue;137 138 daddr = drm_fb_dma_get_gem_addr(state->fb, state, i);139 drm_atomic_helper_damage_iter_init(&iter, old_state, state);140 141 drm_atomic_for_each_plane_damage(&iter, &clip) {142 /* Ignore x1/x2 values, invalidate complete lines */143 offset = clip.y1 * state->fb->pitches[i];144 145 nb_bytes = (clip.y2 - clip.y1) * state->fb->pitches[i];146 dma_sync_single_for_device(drm->dev, daddr + offset,147 nb_bytes, DMA_TO_DEVICE);148 }149 }150}151EXPORT_SYMBOL_GPL(drm_fb_dma_sync_non_coherent);152 153/**154 * drm_fb_dma_get_scanout_buffer - Provide a scanout buffer in case of panic155 * @plane: DRM primary plane156 * @sb: scanout buffer for the panic handler157 * Returns: 0 or negative error code158 *159 * Generic get_scanout_buffer() implementation, for drivers that uses the160 * drm_fb_dma_helper. It won't call vmap in the panic context, so the driver161 * should make sure the primary plane is vmapped, otherwise the panic screen162 * won't get displayed.163 */164int drm_fb_dma_get_scanout_buffer(struct drm_plane *plane,165 struct drm_scanout_buffer *sb)166{167 struct drm_gem_dma_object *dma_obj;168 struct drm_framebuffer *fb;169 170 if (!plane->state || !plane->state->fb)171 return -EINVAL;172 173 fb = plane->state->fb;174 /* Only support linear modifier */175 if (fb->modifier != DRM_FORMAT_MOD_LINEAR)176 return -ENODEV;177 178 dma_obj = drm_fb_dma_get_gem_obj(fb, 0);179 180 /* Buffer should be accessible from the CPU */181 if (dma_obj->base.import_attach)182 return -ENODEV;183 184 /* Buffer should be already mapped to CPU */185 if (!dma_obj->vaddr)186 return -ENODEV;187 188 iosys_map_set_vaddr(&sb->map[0], dma_obj->vaddr);189 sb->format = fb->format;190 sb->height = fb->height;191 sb->width = fb->width;192 sb->pitch[0] = fb->pitches[0];193 return 0;194}195EXPORT_SYMBOL(drm_fb_dma_get_scanout_buffer);196