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_fb_cma_helper.h>
13#include <drm/drm_fourcc.h>
14#include <drm/drm_framebuffer.h>
15#include <drm/drm_gem_cma_helper.h>
16#include <drm/drm_gem_framebuffer_helper.h>
17#include <drm/drm_plane.h>
18#include <linux/module.h>
19
20/**
21 * DOC: framebuffer cma helper functions
22 *
23 * Provides helper functions for creating a cma (contiguous memory allocator)
24 * backed framebuffer.
25 *
26 * drm_gem_fb_create() is used in the &drm_mode_config_funcs.fb_create
27 * callback function to create a cma backed framebuffer.
28 */
29
30/**
31 * drm_fb_cma_get_gem_obj() - Get CMA GEM object for framebuffer
32 * @fb: The framebuffer
33 * @plane: Which plane
34 *
35 * Return the CMA GEM object for given framebuffer.
36 *
37 * This function will usually be called from the CRTC callback functions.
38 */
39struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
40						  unsigned int plane)
41{
42	struct drm_gem_object *gem;
43
44	gem = drm_gem_fb_get_obj(fb, plane);
45	if (!gem)
46		return NULL;
47
48	return to_drm_gem_cma_obj(gem);
49}
50EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_obj);
51
52/**
53 * drm_fb_cma_get_gem_addr() - Get physical address for framebuffer, for pixel
54 * formats where values are grouped in blocks this will get you the beginning of
55 * the block
56 * @fb: The framebuffer
57 * @state: Which state of drm plane
58 * @plane: Which plane
59 * Return the CMA GEM address for given framebuffer.
60 *
61 * This function will usually be called from the PLANE callback functions.
62 */
63dma_addr_t drm_fb_cma_get_gem_addr(struct drm_framebuffer *fb,
64				   struct drm_plane_state *state,
65				   unsigned int plane)
66{
67	struct drm_gem_cma_object *obj;
68	dma_addr_t paddr;
69	u8 h_div = 1, v_div = 1;
70	u32 block_w = drm_format_info_block_width(fb->format, plane);
71	u32 block_h = drm_format_info_block_height(fb->format, plane);
72	u32 block_size = fb->format->char_per_block[plane];
73	u32 sample_x;
74	u32 sample_y;
75	u32 block_start_y;
76	u32 num_hblocks;
77
78	obj = drm_fb_cma_get_gem_obj(fb, plane);
79	if (!obj)
80		return 0;
81
82	paddr = obj->paddr + fb->offsets[plane];
83
84	if (plane > 0) {
85		h_div = fb->format->hsub;
86		v_div = fb->format->vsub;
87	}
88
89	sample_x = (state->src_x >> 16) / h_div;
90	sample_y = (state->src_y >> 16) / v_div;
91	block_start_y = (sample_y / block_h) * block_h;
92	num_hblocks = sample_x / block_w;
93
94	paddr += fb->pitches[plane] * block_start_y;
95	paddr += block_size * num_hblocks;
96
97	return paddr;
98}
99EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_addr);