1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * drm kms/fb dma helper functions
  4 *
  5 * Copyright (C) 2012 Analog Devices Inc.
  6 *   Author: Lars-Peter Clausen <lars@metafoo.de>
  7 *
  8 * Based on udl_fbdev.c
  9 *  Copyright (C) 2012 Red Hat
 10 */
 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_plane.h>
 19#include <linux/dma-mapping.h>
 20#include <linux/module.h>
 21
 22/**
 23 * DOC: framebuffer dma helper functions
 24 *
 25 * Provides helper functions for creating a DMA-contiguous framebuffer.
 26 *
 27 * Depending on the platform, the buffers may be physically non-contiguous and
 28 * mapped through an IOMMU or a similar mechanism, or allocated from
 29 * physically-contiguous memory (using, for instance, CMA or a pool of memory
 30 * reserved at early boot). This is handled behind the scenes by the DMA mapping
 31 * API.
 32 *
 33 * drm_gem_fb_create() is used in the &drm_mode_config_funcs.fb_create
 34 * callback function to create a DMA-contiguous framebuffer.
 35 */
 36
 37/**
 38 * drm_fb_dma_get_gem_obj() - Get DMA GEM object for framebuffer
 39 * @fb: The framebuffer
 40 * @plane: Which plane
 41 *
 42 * Return the DMA GEM object for given framebuffer.
 43 *
 44 * This function will usually be called from the CRTC callback functions.
 45 */
 46struct drm_gem_dma_object *drm_fb_dma_get_gem_obj(struct drm_framebuffer *fb,
 47						  unsigned int plane)
 48{
 49	struct drm_gem_object *gem;
 50
 51	gem = drm_gem_fb_get_obj(fb, plane);
 52	if (!gem)
 53		return NULL;
 54
 55	return to_drm_gem_dma_obj(gem);
 56}
 57EXPORT_SYMBOL_GPL(drm_fb_dma_get_gem_obj);
 58
 59/**
 60 * drm_fb_dma_get_gem_addr() - Get DMA (bus) address for framebuffer, for pixel
 61 * formats where values are grouped in blocks this will get you the beginning of
 62 * the block
 63 * @fb: The framebuffer
 64 * @state: Which state of drm plane
 65 * @plane: Which plane
 66 * Return the DMA GEM address for given framebuffer.
 67 *
 68 * This function will usually be called from the PLANE callback functions.
 69 */
 70dma_addr_t drm_fb_dma_get_gem_addr(struct drm_framebuffer *fb,
 71				   struct drm_plane_state *state,
 72				   unsigned int plane)
 73{
 74	struct drm_gem_dma_object *obj;
 75	dma_addr_t dma_addr;
 76	u8 h_div = 1, v_div = 1;
 77	u32 block_w = drm_format_info_block_width(fb->format, plane);
 78	u32 block_h = drm_format_info_block_height(fb->format, plane);
 79	u32 block_size = fb->format->char_per_block[plane];
 80	u32 sample_x;
 81	u32 sample_y;
 82	u32 block_start_y;
 83	u32 num_hblocks;
 84
 85	obj = drm_fb_dma_get_gem_obj(fb, plane);
 86	if (!obj)
 87		return 0;
 88
 89	dma_addr = obj->dma_addr + fb->offsets[plane];
 90
 91	if (plane > 0) {
 92		h_div = fb->format->hsub;
 93		v_div = fb->format->vsub;
 94	}
 95
 96	sample_x = (state->src_x >> 16) / h_div;
 97	sample_y = (state->src_y >> 16) / v_div;
 98	block_start_y = (sample_y / block_h) * block_h;
 99	num_hblocks = sample_x / block_w;
100
101	dma_addr += fb->pitches[plane] * block_start_y;
102	dma_addr += block_size * num_hblocks;
103
104	return dma_addr;
105}
106EXPORT_SYMBOL_GPL(drm_fb_dma_get_gem_addr);
107
108/**
109 * drm_fb_dma_sync_non_coherent - Sync GEM object to non-coherent backing
110 *	memory
111 * @drm: DRM device
112 * @old_state: Old plane state
113 * @state: New plane state
114 *
115 * This function can be used by drivers that use damage clips and have
116 * DMA GEM objects backed by non-coherent memory. Calling this function
117 * in a plane's .atomic_update ensures that all the data in the backing
118 * memory have been written to RAM.
119 */
120void drm_fb_dma_sync_non_coherent(struct drm_device *drm,
121				  struct drm_plane_state *old_state,
122				  struct drm_plane_state *state)
123{
124	const struct drm_format_info *finfo = state->fb->format;
125	struct drm_atomic_helper_damage_iter iter;
126	const struct drm_gem_dma_object *dma_obj;
127	unsigned int offset, i;
128	struct drm_rect clip;
129	dma_addr_t daddr;
130	size_t nb_bytes;
131
132	for (i = 0; i < finfo->num_planes; i++) {
133		dma_obj = drm_fb_dma_get_gem_obj(state->fb, i);
134		if (!dma_obj->map_noncoherent)
135			continue;
136
137		daddr = drm_fb_dma_get_gem_addr(state->fb, state, i);
138		drm_atomic_helper_damage_iter_init(&iter, old_state, state);
139
140		drm_atomic_for_each_plane_damage(&iter, &clip) {
141			/* Ignore x1/x2 values, invalidate complete lines */
142			offset = clip.y1 * state->fb->pitches[i];
143
144			nb_bytes = (clip.y2 - clip.y1) * state->fb->pitches[i];
145			dma_sync_single_for_device(drm->dev, daddr + offset,
146						   nb_bytes, DMA_TO_DEVICE);
147		}
148	}
149}
150EXPORT_SYMBOL_GPL(drm_fb_dma_sync_non_coherent);