drivers/video/hdmi.c

   1 /*
   2  * Copyright (C) 2012 Avionic Design GmbH
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/bitops.h>
  10 #include <linux/errno.h>
  11 #include <linux/export.h>
  12 #include <linux/hdmi.h>
  13 #include <linux/string.h>
  14
  15 static void hdmi_infoframe_checksum(void *buffer, size_t size)
  16 {
  17         u8 *ptr = buffer;
  18         u8 csum = 0;
  19         size_t i;
  20
  21         /* compute checksum */
  22         for (i = 0; i < size; i++)
  23                 csum += ptr[i];
  24
  25         ptr[3] = 256 - csum;
  26 }
  27
  28 /**
  29  * hdmi_avi_infoframe_init() - initialize an HDMI AVI infoframe
  30  * @frame: HDMI AVI infoframe
  31  *
  32  * Returns 0 on success or a negative error code on failure.
  33  */
  34 int hdmi_avi_infoframe_init(struct hdmi_avi_infoframe *frame)
  35 {
  36         memset(frame, 0, sizeof(*frame));
  37
  38         frame->type = HDMI_INFOFRAME_TYPE_AVI;
  39         frame->version = 2;
  40         frame->length = 13;
  41
  42         return 0;
  43 }
  44 EXPORT_SYMBOL(hdmi_avi_infoframe_init);
  45
  46 /**
  47  * hdmi_avi_infoframe_pack() - write HDMI AVI infoframe to binary buffer
  48  * @frame: HDMI AVI infoframe
  49  * @buffer: destination buffer
  50  * @size: size of buffer
  51  *
  52  * Packs the information contained in the @frame structure into a binary
  53  * representation that can be written into the corresponding controller
  54  * registers. Also computes the checksum as required by section 5.3.5 of
  55  * the HDMI 1.4 specification.
  56  *
  57  * Returns the number of bytes packed into the binary buffer or a negative
  58  * error code on failure.
  59  */
  60 ssize_t hdmi_avi_infoframe_pack(struct hdmi_avi_infoframe *frame, void *buffer,
  61                                 size_t size)
  62 {
  63         u8 *ptr = buffer;
  64         size_t length;
  65
  66         length = HDMI_INFOFRAME_HEADER_SIZE + frame->length;
  67
  68         if (size < length)
  69                 return -ENOSPC;
  70
  71         memset(buffer, 0, length);
  72
  73         ptr[0] = frame->type;
  74         ptr[1] = frame->version;
  75         ptr[2] = frame->length;
  76         ptr[3] = 0; /* checksum */
  77
  78         /* start infoframe payload */
  79         ptr += HDMI_INFOFRAME_HEADER_SIZE;
  80
  81         ptr[0] = ((frame->colorspace & 0x3) << 5) | (frame->scan_mode & 0x3);
  82
  83         if (frame->active_info_valid)
  84                 ptr[0] |= BIT(4);
  85
  86         if (frame->horizontal_bar_valid)
  87                 ptr[0] |= BIT(3);
  88
  89         if (frame->vertical_bar_valid)
  90                 ptr[0] |= BIT(2);
  91
  92         ptr[1] = ((frame->colorimetry & 0x3) << 6) |
  93                  ((frame->picture_aspect & 0x3) << 4) |
  94                  (frame->active_aspect & 0xf);
  95
  96         ptr[2] = ((frame->extended_colorimetry & 0x7) << 4) |
  97                  ((frame->quantization_range & 0x3) << 2) |
  98                  (frame->nups & 0x3);
  99
 100         if (frame->itc)
 101                 ptr[2] |= BIT(7);
 102
 103         ptr[3] = frame->video_code & 0x7f;
 104
 105         ptr[4] = ((frame->ycc_quantization_range & 0x3) << 6) |
 106                  ((frame->content_type & 0x3) << 4) |
 107                  (frame->pixel_repeat & 0xf);
 108
 109         ptr[5] = frame->top_bar & 0xff;
 110         ptr[6] = (frame->top_bar >> 8) & 0xff;
 111         ptr[7] = frame->bottom_bar & 0xff;
 112         ptr[8] = (frame->bottom_bar >> 8) & 0xff;
 113         ptr[9] = frame->left_bar & 0xff;
 114         ptr[10] = (frame->left_bar >> 8) & 0xff;
 115         ptr[11] = frame->right_bar & 0xff;
 116         ptr[12] = (frame->right_bar >> 8) & 0xff;
 117
 118         hdmi_infoframe_checksum(buffer, length);
 119
 120         return length;
 121 }
 122 EXPORT_SYMBOL(hdmi_avi_infoframe_pack);
 123
 124 /**
 125  * hdmi_spd_infoframe_init() - initialize an HDMI SPD infoframe
 126  * @frame: HDMI SPD infoframe
 127  * @vendor: vendor string
 128  * @product: product string
 129  *
 130  * Returns 0 on success or a negative error code on failure.
 131  */
 132 int hdmi_spd_infoframe_init(struct hdmi_spd_infoframe *frame,
 133                             const char *vendor, const char *product)
 134 {
 135         memset(frame, 0, sizeof(*frame));
 136
 137         frame->type = HDMI_INFOFRAME_TYPE_SPD;
 138         frame->version = 1;
 139         frame->length = 25;
 140
 141         strncpy(frame->vendor, vendor, sizeof(frame->vendor));
 142         strncpy(frame->product, product, sizeof(frame->product));
 143
 144         return 0;
 145 }
 146 EXPORT_SYMBOL(hdmi_spd_infoframe_init);
 147
 148 /**
 149  * hdmi_spd_infoframe_pack() - write HDMI SPD infoframe to binary buffer
 150  * @frame: HDMI SPD infoframe
 151  * @buffer: destination buffer
 152  * @size: size of buffer
 153  *
 154  * Packs the information contained in the @frame structure into a binary
 155  * representation that can be written into the corresponding controller
 156  * registers. Also computes the checksum as required by section 5.3.5 of
 157  * the HDMI 1.4 specification.
 158  *
 159  * Returns the number of bytes packed into the binary buffer or a negative
 160  * error code on failure.
 161  */
 162 ssize_t hdmi_spd_infoframe_pack(struct hdmi_spd_infoframe *frame, void *buffer,
 163                                 size_t size)
 164 {
 165         u8 *ptr = buffer;
 166         size_t length;
 167
 168         length = HDMI_INFOFRAME_HEADER_SIZE + frame->length;
 169
 170         if (size < length)
 171                 return -ENOSPC;
 172
 173         memset(buffer, 0, length);
 174
 175         ptr[0] = frame->type;
 176         ptr[1] = frame->version;
 177         ptr[2] = frame->length;
 178         ptr[3] = 0; /* checksum */
 179
 180         /* start infoframe payload */
 181         ptr += HDMI_INFOFRAME_HEADER_SIZE;
 182
 183         memcpy(ptr, frame->vendor, sizeof(frame->vendor));
 184         memcpy(ptr + 8, frame->product, sizeof(frame->product));
 185
 186         ptr[24] = frame->sdi;
 187
 188         hdmi_infoframe_checksum(buffer, length);
 189
 190         return length;
 191 }
 192 EXPORT_SYMBOL(hdmi_spd_infoframe_pack);
 193
 194 /**
 195  * hdmi_audio_infoframe_init() - initialize an HDMI audio infoframe
 196  * @frame: HDMI audio infoframe
 197  *
 198  * Returns 0 on success or a negative error code on failure.
 199  */
 200 int hdmi_audio_infoframe_init(struct hdmi_audio_infoframe *frame)
 201 {
 202         memset(frame, 0, sizeof(*frame));
 203
 204         frame->type = HDMI_INFOFRAME_TYPE_AUDIO;
 205         frame->version = 1;
 206         frame->length = 10;
 207
 208         return 0;
 209 }
 210 EXPORT_SYMBOL(hdmi_audio_infoframe_init);
 211
 212 /**
 213  * hdmi_audio_infoframe_pack() - write HDMI audio infoframe to binary buffer
 214  * @frame: HDMI audio infoframe
 215  * @buffer: destination buffer
 216  * @size: size of buffer
 217  *
 218  * Packs the information contained in the @frame structure into a binary
 219  * representation that can be written into the corresponding controller
 220  * registers. Also computes the checksum as required by section 5.3.5 of
 221  * the HDMI 1.4 specification.
 222  *
 223  * Returns the number of bytes packed into the binary buffer or a negative
 224  * error code on failure.
 225  */
 226 ssize_t hdmi_audio_infoframe_pack(struct hdmi_audio_infoframe *frame,
 227                                   void *buffer, size_t size)
 228 {
 229         unsigned char channels;
 230         u8 *ptr = buffer;
 231         size_t length;
 232
 233         length = HDMI_INFOFRAME_HEADER_SIZE + frame->length;
 234
 235         if (size < length)
 236                 return -ENOSPC;
 237
 238         memset(buffer, 0, length);
 239
 240         if (frame->channels >= 2)
 241                 channels = frame->channels - 1;
 242         else
 243                 channels = 0;
 244
 245         ptr[0] = frame->type;
 246         ptr[1] = frame->version;
 247         ptr[2] = frame->length;
 248         ptr[3] = 0; /* checksum */
 249
 250         /* start infoframe payload */
 251         ptr += HDMI_INFOFRAME_HEADER_SIZE;
 252
 253         ptr[0] = ((frame->coding_type & 0xf) << 4) | (channels & 0x7);
 254         ptr[1] = ((frame->sample_frequency & 0x7) << 2) |
 255                  (frame->sample_size & 0x3);
 256         ptr[2] = frame->coding_type_ext & 0x1f;
 257         ptr[3] = frame->channel_allocation;
 258         ptr[4] = (frame->level_shift_value & 0xf) << 3;
 259
 260         if (frame->downmix_inhibit)
 261                 ptr[4] |= BIT(7);
 262
 263         hdmi_infoframe_checksum(buffer, length);
 264
 265         return length;
 266 }
 267 EXPORT_SYMBOL(hdmi_audio_infoframe_pack);
 268
 269 /**
 270  * hdmi_vendor_infoframe_pack() - write a HDMI vendor infoframe to binary
 271  *                                buffer
 272  * @frame: HDMI vendor infoframe
 273  * @buffer: destination buffer
 274  * @size: size of buffer
 275  *
 276  * Packs the information contained in the @frame structure into a binary
 277  * representation that can be written into the corresponding controller
 278  * registers. Also computes the checksum as required by section 5.3.5 of
 279  * the HDMI 1.4 specification.
 280  *
 281  * Returns the number of bytes packed into the binary buffer or a negative
 282  * error code on failure.
 283  */
 284 ssize_t hdmi_vendor_infoframe_pack(struct hdmi_vendor_infoframe *frame,
 285                                    void *buffer, size_t size)
 286 {
 287         u8 *ptr = buffer;
 288         size_t length;
 289
 290         length = HDMI_INFOFRAME_HEADER_SIZE + frame->length;
 291
 292         if (size < length)
 293                 return -ENOSPC;
 294
 295         memset(buffer, 0, length);
 296
 297         ptr[0] = frame->type;
 298         ptr[1] = frame->version;
 299         ptr[2] = frame->length;
 300         ptr[3] = 0; /* checksum */
 301
 302         memcpy(&ptr[HDMI_INFOFRAME_HEADER_SIZE], frame->data, frame->length);
 303
 304         hdmi_infoframe_checksum(buffer, length);
 305
 306         return length;
 307 }
 308 EXPORT_SYMBOL(hdmi_vendor_infoframe_pack);