1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * drm kms/fb cma (contiguous memory allocator) 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_cma_helper.h>
 14#include <drm/drm_fourcc.h>
 15#include <drm/drm_framebuffer.h>
 16#include <drm/drm_gem_cma_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 cma helper functions
 24 *
 25 * Provides helper functions for creating a cma (contiguous memory allocator)
 26 * backed framebuffer.
 27 *
 28 * drm_gem_fb_create() is used in the &drm_mode_config_funcs.fb_create
 29 * callback function to create a cma backed framebuffer.
 30 */
 31
 32/**
 33 * drm_fb_cma_get_gem_obj() - Get CMA GEM object for framebuffer
 34 * @fb: The framebuffer
 35 * @plane: Which plane
 36 *
 37 * Return the CMA GEM object for given framebuffer.
 38 *
 39 * This function will usually be called from the CRTC callback functions.
 40 */
 41struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
 42						  unsigned int plane)
 43{
 44	struct drm_gem_object *gem;
 45
 46	gem = drm_gem_fb_get_obj(fb, plane);
 47	if (!gem)
 48		return NULL;
 49
 50	return to_drm_gem_cma_obj(gem);
 51}
 52EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_obj);
 53
 54/**
 55 * drm_fb_cma_get_gem_addr() - Get physical address for framebuffer, for pixel
 56 * formats where values are grouped in blocks this will get you the beginning of
 57 * the block
 58 * @fb: The framebuffer
 59 * @state: Which state of drm plane
 60 * @plane: Which plane
 61 * Return the CMA GEM address for given framebuffer.
 62 *
 63 * This function will usually be called from the PLANE callback functions.
 64 */
 65dma_addr_t drm_fb_cma_get_gem_addr(struct drm_framebuffer *fb,
 66				   struct drm_plane_state *state,
 67				   unsigned int plane)
 68{
 69	struct drm_gem_cma_object *obj;
 70	dma_addr_t paddr;
 71	u8 h_div = 1, v_div = 1;
 72	u32 block_w = drm_format_info_block_width(fb->format, plane);
 73	u32 block_h = drm_format_info_block_height(fb->format, plane);
 74	u32 block_size = fb->format->char_per_block[plane];
 75	u32 sample_x;
 76	u32 sample_y;
 77	u32 block_start_y;
 78	u32 num_hblocks;
 79
 80	obj = drm_fb_cma_get_gem_obj(fb, plane);
 81	if (!obj)
 82		return 0;
 83
 84	paddr = obj->paddr + fb->offsets[plane];
 85
 86	if (plane > 0) {
 87		h_div = fb->format->hsub;
 88		v_div = fb->format->vsub;
 89	}
 90
 91	sample_x = (state->src_x >> 16) / h_div;
 92	sample_y = (state->src_y >> 16) / v_div;
 93	block_start_y = (sample_y / block_h) * block_h;
 94	num_hblocks = sample_x / block_w;
 95
 96	paddr += fb->pitches[plane] * block_start_y;
 97	paddr += block_size * num_hblocks;
 98
 99	return paddr;
100}
101EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_addr);
102
103/**
104 * drm_fb_cma_sync_non_coherent - Sync GEM object to non-coherent backing
105 *	memory
106 * @drm: DRM device
107 * @old_state: Old plane state
108 * @state: New plane state
109 *
110 * This function can be used by drivers that use damage clips and have
111 * CMA GEM objects backed by non-coherent memory. Calling this function
112 * in a plane's .atomic_update ensures that all the data in the backing
113 * memory have been written to RAM.
114 */
115void drm_fb_cma_sync_non_coherent(struct drm_device *drm,
116				  struct drm_plane_state *old_state,
117				  struct drm_plane_state *state)
118{
119	const struct drm_format_info *finfo = state->fb->format;
120	struct drm_atomic_helper_damage_iter iter;
121	const struct drm_gem_cma_object *cma_obj;
122	unsigned int offset, i;
123	struct drm_rect clip;
124	dma_addr_t daddr;
125	size_t nb_bytes;
126
127	for (i = 0; i < finfo->num_planes; i++) {
128		cma_obj = drm_fb_cma_get_gem_obj(state->fb, i);
129		if (!cma_obj->map_noncoherent)
130			continue;
131
132		daddr = drm_fb_cma_get_gem_addr(state->fb, state, i);
133		drm_atomic_helper_damage_iter_init(&iter, old_state, state);
134
135		drm_atomic_for_each_plane_damage(&iter, &clip) {
136			/* Ignore x1/x2 values, invalidate complete lines */
137			offset = clip.y1 * state->fb->pitches[i];
138
139			nb_bytes = (clip.y2 - clip.y1) * state->fb->pitches[i];
140			dma_sync_single_for_device(drm->dev, daddr + offset,
141						   nb_bytes, DMA_TO_DEVICE);
142		}
143	}
144}
145EXPORT_SYMBOL_GPL(drm_fb_cma_sync_non_coherent);