drivers/gpu/drm/drm_fb_cma_helper.c

   1 /*
   2  * drm kms/fb cma (contiguous memory allocator) helper functions
   3  *
   4  * Copyright (C) 2012 Analog Device Inc.
   5  *   Author: Lars-Peter Clausen <lars@metafoo.de>
   6  *
   7  * Based on udl_fbdev.c
   8  *  Copyright (C) 2012 Red Hat
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  */
  19
  20 #include <drm/drm_fourcc.h>
  21 #include <drm/drm_framebuffer.h>
  22 #include <drm/drm_gem_cma_helper.h>
  23 #include <drm/drm_gem_framebuffer_helper.h>
  24 #include <drm/drm_plane.h>
  25 #include <linux/module.h>
  26
  27 /**
  28  * DOC: framebuffer cma helper functions
  29  *
  30  * Provides helper functions for creating a cma (contiguous memory allocator)
  31  * backed framebuffer.
  32  *
  33  * drm_gem_fb_create() is used in the &drm_mode_config_funcs.fb_create
  34  * callback function to create a cma backed framebuffer.
  35  */
  36
  37 /**
  38  * drm_fb_cma_get_gem_obj() - Get CMA GEM object for framebuffer
  39  * @fb: The framebuffer
  40  * @plane: Which plane
  41  *
  42  * Return the CMA GEM object for given framebuffer.
  43  *
  44  * This function will usually be called from the CRTC callback functions.
  45  */
  46 struct drm_gem_cma_object *drm_fb_cma_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_cma_obj(gem);
  56 }
  57 EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_obj);
  58
  59 /**
  60  * drm_fb_cma_get_gem_addr() - Get physical 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 CMA GEM address for given framebuffer.
  67  *
  68  * This function will usually be called from the PLANE callback functions.
  69  */
  70 dma_addr_t drm_fb_cma_get_gem_addr(struct drm_framebuffer *fb,
  71                                    struct drm_plane_state *state,
  72                                    unsigned int plane)
  73 {
  74         struct drm_gem_cma_object *obj;
  75         dma_addr_t paddr;
  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_cma_get_gem_obj(fb, plane);
  86         if (!obj)
  87                 return 0;
  88
  89         paddr = obj->paddr + 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         paddr += fb->pitches[plane] * block_start_y;
 102         paddr += block_size * num_hblocks;
 103
 104         return paddr;
 105 }
 106 EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_addr);