firewire: sbp2: provide fallback if mgt_ORB_timeout is missing

The Unit_Characteristics entry of an SBP-2 unit directory is not mandatory as far as I can tell. If it is missing, we would probably fail to log in into the target because firewire-sbp2 would not wait for status after it sent the login request. The fix moves the cleanup of tgt->mgt_orb_timeout into a place where it is executed exactly once before login, rather than 0..n times depending on the target's config ROM. With targets with one or more Unit_Characteristics entries, the result is the same as before. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

firewire: sbp2: provide fallback if mgt_ORB_timeout is missing
The Unit_Characteristics entry of an SBP-2 unit directory is not mandatory as far as I can tell. If it is missing, we would probably fail to log in into the target because firewire-sbp2 would not wait for status after it sent the login request. The fix moves the cleanup of tgt->mgt_orb_timeout into a place where it is executed exactly once before login, rather than 0..n times depending on the target's config ROM. With targets with one or more Unit_Characteristics entries, the result is the same as before. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Stefan Richter
1 parent 544df55d6c
Showing 1 changed file with 19 additions and 20 deletions Side-by-side Diff
drivers/firewire/sbp2.c
@@ -188,14 +188,7 @@
 /* Impossible login_id, to detect logout attempt before successful login */
 #define INVALID_LOGIN_ID 0x10000
  
-/*
- * Per section 7.4.8 of the SBP-2 spec, a mgt_ORB_timeout value can be
- * provided in the config rom. Most devices do provide a value, which
- * we'll use for login management orbs, but with some sane limits.
- */
-#define SBP2_MIN_LOGIN_ORB_TIMEOUT	5000U	/* Timeout in ms */
-#define SBP2_MAX_LOGIN_ORB_TIMEOUT	40000U	/* Timeout in ms */
-#define SBP2_ORB_TIMEOUT		2000U	/* Timeout in ms */
+#define SBP2_ORB_TIMEOUT		2000U		/* Timeout in ms */
 #define SBP2_ORB_NULL			0x80000000
 #define SBP2_RETRY_LIMIT		0xf		/* 15 retries */
 #define SBP2_CYCLE_LIMIT		(0xc8 << 12)	/* 200 125us cycles */
@@ -1034,7 +1027,6 @@
 {
 	struct fw_csr_iterator ci;
 	int key, value;
-	unsigned int timeout;
  
 	fw_csr_iterator_init(&ci, directory);
 	while (fw_csr_iterator_next(&ci, &key, &value)) {
@@ -1059,17 +1051,7 @@
  
 		case SBP2_CSR_UNIT_CHARACTERISTICS:
 			/* the timeout value is stored in 500ms units */
-			timeout = ((unsigned int) value >> 8 & 0xff) * 500;
-			timeout = max(timeout, SBP2_MIN_LOGIN_ORB_TIMEOUT);
-			tgt->mgt_orb_timeout =
-				  min(timeout, SBP2_MAX_LOGIN_ORB_TIMEOUT);
-
-			if (timeout > tgt->mgt_orb_timeout)
-				fw_notify("%s: config rom contains %ds "
-					  "management ORB timeout, limiting "
-					  "to %ds\n", tgt->bus_id,
-					  timeout / 1000,
-					  tgt->mgt_orb_timeout / 1000);
+			tgt->mgt_orb_timeout = (value >> 8 & 0xff) * 500;
 			break;
  
 		case SBP2_CSR_LOGICAL_UNIT_NUMBER:
@@ -1087,6 +1069,22 @@
 	return 0;
 }
  
+/*
+ * Per section 7.4.8 of the SBP-2 spec, a mgt_ORB_timeout value can be
+ * provided in the config rom. Most devices do provide a value, which
+ * we'll use for login management orbs, but with some sane limits.
+ */
+static void sbp2_clamp_management_orb_timeout(struct sbp2_target *tgt)
+{
+	unsigned int timeout = tgt->mgt_orb_timeout;
+
+	if (timeout > 40000)
+		fw_notify("%s: %ds mgt_ORB_timeout limited to 40s\n",
+			  tgt->bus_id, timeout / 1000);
+
+	tgt->mgt_orb_timeout = clamp_val(timeout, 5000, 40000);
+}
+
 static void sbp2_init_workarounds(struct sbp2_target *tgt, u32 model,
 				  u32 firmware_revision)
 {
@@ -1171,6 +1169,7 @@
 			       &firmware_revision) < 0)
 		goto fail_tgt_put;
  
+	sbp2_clamp_management_orb_timeout(tgt);
 	sbp2_init_workarounds(tgt, model, firmware_revision);
  
 	/*
...	...	@@ -188,14 +188,7 @@
188	188	/* Impossible login_id, to detect logout attempt before successful login */
189	189	#define INVALID_LOGIN_ID 0x10000
190	190
191		-/*
192		- * Per section 7.4.8 of the SBP-2 spec, a mgt_ORB_timeout value can be
193		- * provided in the config rom. Most devices do provide a value, which
194		- * we'll use for login management orbs, but with some sane limits.
195		- */
196		-#define SBP2_MIN_LOGIN_ORB_TIMEOUT 5000U /* Timeout in ms */
197		-#define SBP2_MAX_LOGIN_ORB_TIMEOUT 40000U /* Timeout in ms */
198		-#define SBP2_ORB_TIMEOUT 2000U /* Timeout in ms */
	191	+#define SBP2_ORB_TIMEOUT 2000U /* Timeout in ms */
199	192	#define SBP2_ORB_NULL 0x80000000
200	193	#define SBP2_RETRY_LIMIT 0xf /* 15 retries */
201	194	#define SBP2_CYCLE_LIMIT (0xc8 << 12) /* 200 125us cycles */
...	...	@@ -1034,7 +1027,6 @@
1034	1027	{
1035	1028	struct fw_csr_iterator ci;
1036	1029	int key, value;
1037		- unsigned int timeout;
1038	1030
1039	1031	fw_csr_iterator_init(&ci, directory);
1040	1032	while (fw_csr_iterator_next(&ci, &key, &value)) {
...	...	@@ -1059,17 +1051,7 @@
1059	1051
1060	1052	case SBP2_CSR_UNIT_CHARACTERISTICS:
1061	1053	/* the timeout value is stored in 500ms units */
1062		- timeout = ((unsigned int) value >> 8 & 0xff) * 500;
1063		- timeout = max(timeout, SBP2_MIN_LOGIN_ORB_TIMEOUT);
1064		- tgt->mgt_orb_timeout =
1065		- min(timeout, SBP2_MAX_LOGIN_ORB_TIMEOUT);
1066		-
1067		- if (timeout > tgt->mgt_orb_timeout)
1068		- fw_notify("%s: config rom contains %ds "
1069		- "management ORB timeout, limiting "
1070		- "to %ds\n", tgt->bus_id,
1071		- timeout / 1000,
1072		- tgt->mgt_orb_timeout / 1000);
	1054	+ tgt->mgt_orb_timeout = (value >> 8 & 0xff) * 500;
1073	1055	break;
1074	1056
1075	1057	case SBP2_CSR_LOGICAL_UNIT_NUMBER:
...	...	@@ -1087,6 +1069,22 @@
1087	1069	return 0;
1088	1070	}
1089	1071
	1072	+/*
	1073	+ * Per section 7.4.8 of the SBP-2 spec, a mgt_ORB_timeout value can be
	1074	+ * provided in the config rom. Most devices do provide a value, which
	1075	+ * we'll use for login management orbs, but with some sane limits.
	1076	+ */
	1077	+static void sbp2_clamp_management_orb_timeout(struct sbp2_target *tgt)
	1078	+{
	1079	+ unsigned int timeout = tgt->mgt_orb_timeout;
	1080	+
	1081	+ if (timeout > 40000)
	1082	+ fw_notify("%s: %ds mgt_ORB_timeout limited to 40s\n",
	1083	+ tgt->bus_id, timeout / 1000);
	1084	+
	1085	+ tgt->mgt_orb_timeout = clamp_val(timeout, 5000, 40000);
	1086	+}
	1087	+
1090	1088	static void sbp2_init_workarounds(struct sbp2_target *tgt, u32 model,
1091	1089	u32 firmware_revision)
1092	1090	{
...	...	@@ -1171,6 +1169,7 @@
1171	1169	&firmware_revision) < 0)
1172	1170	goto fail_tgt_put;
1173	1171
	1172	+ sbp2_clamp_management_orb_timeout(tgt);
1174	1173	sbp2_init_workarounds(tgt, model, firmware_revision);
1175	1174
1176	1175	/*