[PATCH] Fix missing sysfs vendor/model entries for some devices

[Adam G. <ad...@po...>]

Hi,

When the Sony DVMC-DA1 is connected, /sys/bus/firewire/devices/fw1/ has 
a vendor entry, but is missing vendor_name, model, and model_name.

This is the DVMC-DA1's config ROM:

00000000: fbe7 1e04 3439 3331 0040 64e0 0346 0008  ....4931.@d..F..
00000010: 3c19 1400 81b6 0600 4600 0803 c083 000c  <.......F.......
00000020: 0a00 008d 0300 00d1 0500 00c3 0a00 0081  ................
00000030: bfcd 0200 2da0 0012 0000 0113 fe0c 0200  ....-...........
00000040: 0000 fa17 0800 0081 6ec6 0200 0346 0008  ........n....F..
00000050: 3c19 1400 269e 0300 0000 0000 0000 0000  <...&...........
00000060: 796e 6f53 1d00 0500 0000 0000 0000 0000  ynoS............
00000070: 434d 5644 3141 442d 0000 0000            CMVD1AD-....

Note that the root directory contains two entries for vendor. The first 
is a Vendor_ID immediate value, and the second is a Vendor_Info 
directory. The descriptor for vendor_name is after the Vendor_Info 
entry. However, search_leaf compares the directory entry high byte 
against the desired key_id without masking off the type bits, so it 
doesn't recognize the Vendor_Info entry.

Also, the model and model_name are not in the root directory, but 
instead are in the vendor directory. search_leaf and show_immediate 
don't see these, because they only search the root directory.

The following patch fixes the above problems.

The new behavior is conformant with Annex A of 1394TA Document 1999027, 
Configuration ROM for AV/C Devices 1.0: "Some legacy devices may have 
their Model_IDs and textual descriptors in minimal ASCII subset in their 
vendor directories. It is recommended for a controller to read the 
Model_ID and its descriptor in the vendor directory of a target only if 
the Model_ID and its descriptor are not present in the root directory of 
the target."

In addition to the DVMC-DA1, other devices are also affected. This patch 
also fixes the missing sysfs entries for the Sony DCR-TRV120 and 
Panasonic AG-DV1DC. The Sony DCR-TRV310 has been reported to have the 
same problem and should be fixed by the patch, but I don't have one for 
testing.


--- core-device.c.orig	2023-09-23 02:11:13.000000000 -0700
+++ core-device.c	2023-11-25 20:58:02.000000000 -0800
@@ -54,13 +54,19 @@
 
 	fw_csr_iterator_init(&ci, directory);
 	while (fw_csr_iterator_next(&ci, &key, &value)) {
-		if (last_key == search_key &&
+		if ((last_key & 0x3f) == search_key &&
 		    key == (CSR_DESCRIPTOR | CSR_LEAF))
 			return ci.p - 1 + value;
 
 		last_key = key;
 	}
 
+	/* Not in root directory, check vendor directory if present */
+	fw_csr_iterator_init(&ci, directory);
+	while (fw_csr_iterator_next(&ci, &key, &value))
+		if (key == (CSR_VENDOR | CSR_DIRECTORY))
+			return search_leaf(ci.p - 1 + value, search_key);
+
 	return NULL;
 }
 
@@ -245,14 +251,32 @@
 	u32 key;
 };
 
+static int search_immediate(const u32 *directory, int search_key)
+{
+	struct fw_csr_iterator ci;
+	int key, value;
+
+	fw_csr_iterator_init(&ci, directory);
+	while (fw_csr_iterator_next(&ci, &key, &value))
+		if (key == search_key)
+			return value;
+
+	/* Not in root directory, check vendor directory if present */
+	fw_csr_iterator_init(&ci, directory);
+	while (fw_csr_iterator_next(&ci, &key, &value))
+		if (key == (CSR_VENDOR | CSR_DIRECTORY))
+			return search_immediate(ci.p - 1 + value, search_key);
+
+	return -1;
+}
+
 static ssize_t show_immediate(struct device *dev,
 			      struct device_attribute *dattr, char *buf)
 {
 	struct config_rom_attribute *attr =
 		container_of(dattr, struct config_rom_attribute, attr);
-	struct fw_csr_iterator ci;
 	const u32 *dir;
-	int key, value, ret = -ENOENT;
+	int value, ret = -ENOENT;
 
 	down_read(&fw_device_rwsem);
 
@@ -261,13 +285,9 @@
 	else
 		dir = fw_device(dev)->config_rom + 5;
 
-	fw_csr_iterator_init(&ci, dir);
-	while (fw_csr_iterator_next(&ci, &key, &value))
-		if (attr->key == key) {
-			ret = snprintf(buf, buf ? PAGE_SIZE : 0,
-				       "0x%06x\n", value);
-			break;
-		}
+	value = search_immediate(dir, attr->key);
+	if (value != -1)
+		ret = snprintf(buf, buf ? PAGE_SIZE : 0, "0x%06x\n", value);
 
 	up_read(&fw_device_rwsem);