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![Hans Verkuil](/assets/img/avatar_default.png)
The cec_get_edid_spa_location() function did not verify that the IEEE identifier in the Vendor Specific Data Block matched the HDMI-LLC identifier. This could result in the wrong VSDB block being returned. For example, for HDMI 2.0 EDIDs there is also a HDMI Forum VSDB. So check the IEEE identifier as well. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
171 lines
4.5 KiB
C
171 lines
4.5 KiB
C
/*
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* cec-edid - HDMI Consumer Electronics Control EDID & CEC helper functions
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*
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* Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
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*
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* This program is free software; you may redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <media/cec-edid.h>
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/*
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* This EDID is expected to be a CEA-861 compliant, which means that there are
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* at least two blocks and one or more of the extensions blocks are CEA-861
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* blocks.
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*
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* The returned location is guaranteed to be < size - 1.
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*/
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static unsigned int cec_get_edid_spa_location(const u8 *edid, unsigned int size)
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{
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unsigned int blocks = size / 128;
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unsigned int block;
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u8 d;
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/* Sanity check: at least 2 blocks and a multiple of the block size */
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if (blocks < 2 || size % 128)
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return 0;
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/*
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* If there are fewer extension blocks than the size, then update
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* 'blocks'. It is allowed to have more extension blocks than the size,
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* since some hardware can only read e.g. 256 bytes of the EDID, even
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* though more blocks are present. The first CEA-861 extension block
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* should normally be in block 1 anyway.
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*/
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if (edid[0x7e] + 1 < blocks)
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blocks = edid[0x7e] + 1;
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for (block = 1; block < blocks; block++) {
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unsigned int offset = block * 128;
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/* Skip any non-CEA-861 extension blocks */
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if (edid[offset] != 0x02 || edid[offset + 1] != 0x03)
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continue;
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/* search Vendor Specific Data Block (tag 3) */
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d = edid[offset + 2] & 0x7f;
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/* Check if there are Data Blocks */
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if (d <= 4)
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continue;
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if (d > 4) {
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unsigned int i = offset + 4;
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unsigned int end = offset + d;
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/* Note: 'end' is always < 'size' */
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do {
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u8 tag = edid[i] >> 5;
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u8 len = edid[i] & 0x1f;
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if (tag == 3 && len >= 5 && i + len <= end &&
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edid[i + 1] == 0x03 &&
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edid[i + 2] == 0x0c &&
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edid[i + 3] == 0x00)
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return i + 4;
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i += len + 1;
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} while (i < end);
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}
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}
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return 0;
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}
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u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
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unsigned int *offset)
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{
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unsigned int loc = cec_get_edid_spa_location(edid, size);
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if (offset)
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*offset = loc;
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if (loc == 0)
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return CEC_PHYS_ADDR_INVALID;
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return (edid[loc] << 8) | edid[loc + 1];
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}
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EXPORT_SYMBOL_GPL(cec_get_edid_phys_addr);
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void cec_set_edid_phys_addr(u8 *edid, unsigned int size, u16 phys_addr)
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{
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unsigned int loc = cec_get_edid_spa_location(edid, size);
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u8 sum = 0;
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unsigned int i;
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if (loc == 0)
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return;
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edid[loc] = phys_addr >> 8;
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edid[loc + 1] = phys_addr & 0xff;
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loc &= ~0x7f;
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/* update the checksum */
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for (i = loc; i < loc + 127; i++)
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sum += edid[i];
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edid[i] = 256 - sum;
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}
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EXPORT_SYMBOL_GPL(cec_set_edid_phys_addr);
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u16 cec_phys_addr_for_input(u16 phys_addr, u8 input)
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{
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/* Check if input is sane */
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if (WARN_ON(input == 0 || input > 0xf))
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return CEC_PHYS_ADDR_INVALID;
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if (phys_addr == 0)
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return input << 12;
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if ((phys_addr & 0x0fff) == 0)
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return phys_addr | (input << 8);
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if ((phys_addr & 0x00ff) == 0)
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return phys_addr | (input << 4);
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if ((phys_addr & 0x000f) == 0)
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return phys_addr | input;
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/*
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* All nibbles are used so no valid physical addresses can be assigned
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* to the input.
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*/
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return CEC_PHYS_ADDR_INVALID;
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}
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EXPORT_SYMBOL_GPL(cec_phys_addr_for_input);
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int cec_phys_addr_validate(u16 phys_addr, u16 *parent, u16 *port)
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{
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int i;
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if (parent)
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*parent = phys_addr;
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if (port)
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*port = 0;
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if (phys_addr == CEC_PHYS_ADDR_INVALID)
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return 0;
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for (i = 0; i < 16; i += 4)
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if (phys_addr & (0xf << i))
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break;
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if (i == 16)
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return 0;
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if (parent)
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*parent = phys_addr & (0xfff0 << i);
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if (port)
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*port = (phys_addr >> i) & 0xf;
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for (i += 4; i < 16; i += 4)
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if ((phys_addr & (0xf << i)) == 0)
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return -EINVAL;
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return 0;
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}
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EXPORT_SYMBOL_GPL(cec_phys_addr_validate);
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MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>");
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MODULE_DESCRIPTION("CEC EDID helper functions");
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MODULE_LICENSE("GPL");
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