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 */
drm_fb_cma_get_gem_obj(struct drm_framebuffer * fb,unsigned int plane)38 struct 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 }
49 EXPORT_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 */
drm_fb_cma_get_gem_addr(struct drm_framebuffer * fb,struct drm_plane_state * state,unsigned int plane)62 dma_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 }
98 EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_addr);
99