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From: Stefan Richter on 7 Oct 2009 19:00
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(a)s5r6.in-berlin.de>
---
drivers/firewire/sbp2.c | 39 +++++++++++++++++++--------------------
1 file changed, 19 insertions(+), 20 deletions(-)

Index: linux-2.6.31/drivers/firewire/sbp2.c
===================================================================
--- linux-2.6.31.orig/drivers/firewire/sbp2.c
+++ linux-2.6.31/drivers/firewire/sbp2.c
@@ -188,14 +188,7 @@ static struct fw_device *target_device(s
/* 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 @@ static int sbp2_scan_unit_dir(struct sbp
{
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 @@ static int sbp2_scan_unit_dir(struct sbp

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 @@ static int sbp2_scan_unit_dir(struct sbp
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 @@ static int sbp2_probe(struct device *dev
&firmware_revision) < 0)
goto fail_tgt_put;

+ sbp2_clamp_management_orb_timeout(tgt);
sbp2_init_workarounds(tgt, model, firmware_revision);

/*

--
Stefan Richter
-=====-==--= =-=- -=---
http://arcgraph.de/sr/

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