4 files changed, 277 insertions, 0 deletions

diff --git a/drivers/media/Kconfig b/drivers/media/Kconfig
index a8518fb3bca7..052dcf77174b 100644
--- a/drivers/media/Kconfig
+++ b/drivers/media/Kconfig
@@ -80,6 +80,9 @@ config MEDIA_RC_SUPPORT
 
           Say Y when you have a TV or an IR device.
 
+config MEDIA_CEC_EDID
+        tristate
+
 #
 # Media controller
 #       Selectable only for webcam/grabbers, as other drivers don't use it
diff --git a/drivers/media/Makefile b/drivers/media/Makefile
index e608bbce0c35..b56f013b78c3 100644
--- a/drivers/media/Makefile
+++ b/drivers/media/Makefile
@@ -2,6 +2,8 @@
 # Makefile for the kernel multimedia device drivers.
 #
 
+obj-$(CONFIG_MEDIA_CEC_EDID) += cec-edid.o
+
 media-objs      := media-device.o media-devnode.o media-entity.o
 
 #
diff --git a/drivers/media/cec-edid.c b/drivers/media/cec-edid.c
new file mode 100644
index 000000000000..70018247bdda
--- /dev/null
+++ b/drivers/media/cec-edid.c
@@ -0,0 +1,168 @@
+/*
+ * 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");
diff --git a/include/media/cec-edid.h b/include/media/cec-edid.h
new file mode 100644
index 000000000000..bdf731ecba1a
--- /dev/null
+++ b/include/media/cec-edid.h
@@ -0,0 +1,104 @@
+/*
+ * 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 */