--- /dev/null
+/*
+ * cec-edid - HDMI Consumer Electronics Control EDID & CEC helper functions
+ *
+ * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <media/cec-edid.h>
+
+/*
+ * This EDID is expected to be a CEA-861 compliant, which means that there are
+ * at least two blocks and one or more of the extensions blocks are CEA-861
+ * blocks.
+ *
+ * The returned location is guaranteed to be < size - 1.
+ */
+static unsigned int cec_get_edid_spa_location(const u8 *edid, unsigned int size)
+{
+ unsigned int blocks = size / 128;
+ unsigned int block;
+ u8 d;
+
+ /* Sanity check: at least 2 blocks and a multiple of the block size */
+ if (blocks < 2 || size % 128)
+ return 0;
+
+ /*
+ * If there are fewer extension blocks than the size, then update
+ * 'blocks'. It is allowed to have more extension blocks than the size,
+ * since some hardware can only read e.g. 256 bytes of the EDID, even
+ * though more blocks are present. The first CEA-861 extension block
+ * should normally be in block 1 anyway.
+ */
+ if (edid[0x7e] + 1 < blocks)
+ blocks = edid[0x7e] + 1;
+
+ for (block = 1; block < blocks; block++) {
+ unsigned int offset = block * 128;
+
+ /* Skip any non-CEA-861 extension blocks */
+ if (edid[offset] != 0x02 || edid[offset + 1] != 0x03)
+ continue;
+
+ /* search Vendor Specific Data Block (tag 3) */
+ d = edid[offset + 2] & 0x7f;
+ /* Check if there are Data Blocks */
+ if (d <= 4)
+ continue;
+ if (d > 4) {
+ unsigned int i = offset + 4;
+ unsigned int end = offset + d;
+
+ /* Note: 'end' is always < 'size' */
+ do {
+ u8 tag = edid[i] >> 5;
+ u8 len = edid[i] & 0x1f;
+
+ if (tag == 3 && len >= 5 && i + len <= end)
+ return i + 4;
+ i += len + 1;
+ } while (i < end);
+ }
+ }
+ return 0;
+}
+
+u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
+ unsigned int *offset)
+{
+ unsigned int loc = cec_get_edid_spa_location(edid, size);
+
+ if (offset)
+ *offset = loc;
+ if (loc == 0)
+ return CEC_PHYS_ADDR_INVALID;
+ return (edid[loc] << 8) | edid[loc + 1];
+}
+EXPORT_SYMBOL_GPL(cec_get_edid_phys_addr);
+
+void cec_set_edid_phys_addr(u8 *edid, unsigned int size, u16 phys_addr)
+{
+ unsigned int loc = cec_get_edid_spa_location(edid, size);
+ u8 sum = 0;
+ unsigned int i;
+
+ if (loc == 0)
+ return;
+ edid[loc] = phys_addr >> 8;
+ edid[loc + 1] = phys_addr & 0xff;
+ loc &= ~0x7f;
+
+ /* update the checksum */
+ for (i = loc; i < loc + 127; i++)
+ sum += edid[i];
+ edid[i] = 256 - sum;
+}
+EXPORT_SYMBOL_GPL(cec_set_edid_phys_addr);
+
+u16 cec_phys_addr_for_input(u16 phys_addr, u8 input)
+{
+ /* Check if input is sane */
+ if (WARN_ON(input == 0 || input > 0xf))
+ return CEC_PHYS_ADDR_INVALID;
+
+ if (phys_addr == 0)
+ return input << 12;
+
+ if ((phys_addr & 0x0fff) == 0)
+ return phys_addr | (input << 8);
+
+ if ((phys_addr & 0x00ff) == 0)
+ return phys_addr | (input << 4);
+
+ if ((phys_addr & 0x000f) == 0)
+ return phys_addr | input;
+
+ /*
+ * All nibbles are used so no valid physical addresses can be assigned
+ * to the input.
+ */
+ return CEC_PHYS_ADDR_INVALID;
+}
+EXPORT_SYMBOL_GPL(cec_phys_addr_for_input);
+
+int cec_phys_addr_validate(u16 phys_addr, u16 *parent, u16 *port)
+{
+ int i;
+
+ if (parent)
+ *parent = phys_addr;
+ if (port)
+ *port = 0;
+ if (phys_addr == CEC_PHYS_ADDR_INVALID)
+ return 0;
+ for (i = 0; i < 16; i += 4)
+ if (phys_addr & (0xf << i))
+ break;
+ if (i == 16)
+ return 0;
+ if (parent)
+ *parent = phys_addr & (0xfff0 << i);
+ if (port)
+ *port = (phys_addr >> i) & 0xf;
+ for (i += 4; i < 16; i += 4)
+ if ((phys_addr & (0xf << i)) == 0)
+ return -EINVAL;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(cec_phys_addr_validate);
+
+MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>");
+MODULE_DESCRIPTION("CEC EDID helper functions");
+MODULE_LICENSE("GPL");
--- /dev/null
+/*
+ * cec-edid - HDMI Consumer Electronics Control & EDID helpers
+ *
+ * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef _MEDIA_CEC_EDID_H
+#define _MEDIA_CEC_EDID_H
+
+#include <linux/types.h>
+
+#define CEC_PHYS_ADDR_INVALID 0xffff
+#define cec_phys_addr_exp(pa) \
+ ((pa) >> 12), ((pa) >> 8) & 0xf, ((pa) >> 4) & 0xf, (pa) & 0xf
+
+/**
+ * cec_get_edid_phys_addr() - find and return the physical address
+ *
+ * @edid: pointer to the EDID data
+ * @size: size in bytes of the EDID data
+ * @offset: If not %NULL then the location of the physical address
+ * bytes in the EDID will be returned here. This is set to 0
+ * if there is no physical address found.
+ *
+ * Return: the physical address or CEC_PHYS_ADDR_INVALID if there is none.
+ */
+u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
+ unsigned int *offset);
+
+/**
+ * cec_set_edid_phys_addr() - find and set the physical address
+ *
+ * @edid: pointer to the EDID data
+ * @size: size in bytes of the EDID data
+ * @phys_addr: the new physical address
+ *
+ * This function finds the location of the physical address in the EDID
+ * and fills in the given physical address and updates the checksum
+ * at the end of the EDID block. It does nothing if the EDID doesn't
+ * contain a physical address.
+ */
+void cec_set_edid_phys_addr(u8 *edid, unsigned int size, u16 phys_addr);
+
+/**
+ * cec_phys_addr_for_input() - calculate the PA for an input
+ *
+ * @phys_addr: the physical address of the parent
+ * @input: the number of the input port, must be between 1 and 15
+ *
+ * This function calculates a new physical address based on the input
+ * port number. For example:
+ *
+ * PA = 0.0.0.0 and input = 2 becomes 2.0.0.0
+ *
+ * PA = 3.0.0.0 and input = 1 becomes 3.1.0.0
+ *
+ * PA = 3.2.1.0 and input = 5 becomes 3.2.1.5
+ *
+ * PA = 3.2.1.3 and input = 5 becomes f.f.f.f since it maxed out the depth.
+ *
+ * Return: the new physical address or CEC_PHYS_ADDR_INVALID.
+ */
+u16 cec_phys_addr_for_input(u16 phys_addr, u8 input);
+
+/**
+ * cec_phys_addr_validate() - validate a physical address from an EDID
+ *
+ * @phys_addr: the physical address to validate
+ * @parent: if not %NULL, then this is filled with the parents PA.
+ * @port: if not %NULL, then this is filled with the input port.
+ *
+ * This validates a physical address as read from an EDID. If the
+ * PA is invalid (such as 1.0.1.0 since '0' is only allowed at the end),
+ * then it will return -EINVAL.
+ *
+ * The parent PA is passed into %parent and the input port is passed into
+ * %port. For example:
+ *
+ * PA = 0.0.0.0: has parent 0.0.0.0 and input port 0.
+ *
+ * PA = 1.0.0.0: has parent 0.0.0.0 and input port 1.
+ *
+ * PA = 3.2.0.0: has parent 3.0.0.0 and input port 2.
+ *
+ * PA = f.f.f.f: has parent f.f.f.f and input port 0.
+ *
+ * Return: 0 if the PA is valid, -EINVAL if not.
+ */
+int cec_phys_addr_validate(u16 phys_addr, u16 *parent, u16 *port);
+
+#endif /* _MEDIA_CEC_EDID_H */
projects / users / hch / block.git / commitdiff