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 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  */
  39 struct 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 }
  50 EXPORT_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  */
  63 dma_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 }
  99 EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_addr);