thunderbolt: Parse generic drom entries

Initially three types of generic entries are supported: vendor_name,
device_name and apple_serial. Log them for the benefit of the user.

Cc: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>

drivers/thunderbolt/eeprom.c

@@ -5,6 +5,7 @@
  */
 
 #include <linux/crc32.h>
+#include <linux/ctype.h>
 #include <linux/property.h>
 #include <linux/slab.h>
 #include "tb.h"
@@ -292,6 +293,40 @@ int tb_drom_read_uid_only(struct tb_switch *sw, u64 *uid)
 	return 0;
 }
 
+/**
+ * tb_drom_parse_entry_generic - parse generic drom entry
+ *
+ * Do not trust the text string to be null terminated in drom.
+ * Replace nonprintable characters with blanks.
+ */
+static int tb_drom_parse_entry_generic(struct tb_switch *sw,
+				       struct tb_drom_entry_header *header)
+{
+	char *sanitized_text, *text = (char *)header + sizeof(*header);
+	size_t text_len = header->len - sizeof(*header) + 1;
+	int i;
+
+	sanitized_text = kmalloc(text_len, GFP_KERNEL);
+	if (!sanitized_text)
+		return -ENOMEM;
+
+	for (i = 0; i < text_len - 1; i++)
+		sanitized_text[i] = (isascii(text[i]) && isprint(text[i])) ?
+				    text[i] : ' ';
+	sanitized_text[text_len - 1] = '\0';
+
+	switch (header->index) {
+	case 0x01:	sw->vendor_name  = sanitized_text; return 0;
+	case 0x02:	sw->device_name  = sanitized_text; return 0;
+	case 0x30:	sw->apple_serial = sanitized_text; return 0;
+	}
+
+	tb_sw_info(sw, "unknown generic entry %#x: %s\n", header->index,
+		   sanitized_text);
+	kfree(sanitized_text);
+	return 0;
+}
+
 static int tb_drom_parse_entry_port(struct tb_switch *sw,
 				    struct tb_drom_entry_header *header)
 {
@@ -347,6 +382,7 @@ static int tb_drom_parse_entries(struct tb_switch *sw)
 
 		switch (entry->type) {
 		case TB_DROM_ENTRY_GENERIC:
+			res = tb_drom_parse_entry_generic(sw, entry);
 			break;
 		case TB_DROM_ENTRY_PORT:
 			res = tb_drom_parse_entry_port(sw, entry);

drivers/thunderbolt/switch.c

@@ -326,6 +326,9 @@ void tb_switch_free(struct tb_switch *sw)
 	if (!sw->is_unplugged)
 		tb_plug_events_active(sw, false);
 
+	kfree(sw->vendor_name);
+	kfree(sw->device_name);
+	kfree(sw->apple_serial);
 	kfree(sw->ports);
 	kfree(sw->drom);
 	kfree(sw);
@@ -405,6 +408,12 @@ struct tb_switch *tb_switch_alloc(struct tb *tb, u64 route)
 	if (tb_drom_read(sw))
 		tb_sw_warn(sw, "tb_eeprom_read_rom failed, continuing\n");
 	tb_sw_info(sw, "uid: %#llx\n", sw->uid);
+	if (sw->vendor_name)
+		tb_sw_info(sw, "Vendor: %s\n", sw->vendor_name);
+	if (sw->device_name)
+		tb_sw_info(sw, "Device: %s\n", sw->device_name);
+	if (sw->apple_serial)
+		tb_sw_info(sw, "Apple Serial Number: %s\n", sw->apple_serial);
 
 	for (i = 0; i <= sw->config.max_port_number; i++) {
 		if (sw->ports[i].disabled) {

drivers/thunderbolt/tb.h

@@ -23,6 +23,9 @@ struct tb_switch {
 	int cap_plug_events; /* offset, zero if not found */
 	bool is_unplugged; /* unplugged, will go away */
 	u8 *drom;
+	char *vendor_name;
+	char *device_name;
+	char *apple_serial;
 };
 
 /**