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 Device 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_fourcc.h>
13#include <drm/drm_framebuffer.h>
14#include <drm/drm_gem_cma_helper.h>
15#include <drm/drm_gem_framebuffer_helper.h>
16#include <drm/drm_plane.h>
17#include <linux/module.h>
18
19/**
20 * DOC: framebuffer cma helper functions
21 *
22 * Provides helper functions for creating a cma (contiguous memory allocator)
23 * backed framebuffer.
24 *
25 * drm_gem_fb_create() is used in the &drm_mode_config_funcs.fb_create
26 * callback function to create a cma backed framebuffer.
27 */
28
29/**
30 * drm_fb_cma_get_gem_obj() - Get CMA GEM object for framebuffer
31 * @fb: The framebuffer
32 * @plane: Which plane
33 *
34 * Return the CMA GEM object for given framebuffer.
35 *
36 * This function will usually be called from the CRTC callback functions.
37 */
38struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
39						  unsigned int plane)
40{
41	struct drm_gem_object *gem;
42
43	gem = drm_gem_fb_get_obj(fb, plane);
44	if (!gem)
45		return NULL;
46
47	return to_drm_gem_cma_obj(gem);
48}
49EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_obj);
50
51/**
52 * drm_fb_cma_get_gem_addr() - Get physical address for framebuffer, for pixel
53 * formats where values are grouped in blocks this will get you the beginning of
54 * the block
55 * @fb: The framebuffer
56 * @state: Which state of drm plane
57 * @plane: Which plane
58 * Return the CMA GEM address for given framebuffer.
59 *
60 * This function will usually be called from the PLANE callback functions.
61 */
62dma_addr_t drm_fb_cma_get_gem_addr(struct drm_framebuffer *fb,
63				   struct drm_plane_state *state,
64				   unsigned int plane)
65{
66	struct drm_gem_cma_object *obj;
67	dma_addr_t paddr;
68	u8 h_div = 1, v_div = 1;
69	u32 block_w = drm_format_info_block_width(fb->format, plane);
70	u32 block_h = drm_format_info_block_height(fb->format, plane);
71	u32 block_size = fb->format->char_per_block[plane];
72	u32 sample_x;
73	u32 sample_y;
74	u32 block_start_y;
75	u32 num_hblocks;
76
77	obj = drm_fb_cma_get_gem_obj(fb, plane);
78	if (!obj)
79		return 0;
80
81	paddr = obj->paddr + fb->offsets[plane];
82
83	if (plane > 0) {
84		h_div = fb->format->hsub;
85		v_div = fb->format->vsub;
86	}
87
88	sample_x = (state->src_x >> 16) / h_div;
89	sample_y = (state->src_y >> 16) / v_div;
90	block_start_y = (sample_y / block_h) * block_h;
91	num_hblocks = sample_x / block_w;
92
93	paddr += fb->pitches[plane] * block_start_y;
94	paddr += block_size * num_hblocks;
95
96	return paddr;
97}
98EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_addr);