drivers/gpu/drm/drm_fb_cma_helper.c

   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  */
  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  */
  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);