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firewire: sbp2: provide fallback if mgt_ORB_timeout is missing

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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>
This commit is contained in:
Stefan Richter
2009-10-08 00:39:31 +02:00
parent 544df55d6c
commit eaf76e0d02
1 changed files with 19 additions and 20 deletions
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39
drivers/firewire/sbp2.c
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@@ -188,14 +188,7 @@ static struct fw_device *target_device(struct sbp2_target *tgt)
/* Impossible login_id, to detect logout attempt before successful login */ /* Impossible login_id, to detect logout attempt before successful login */
#define INVALID_LOGIN_ID 0x10000 #define INVALID_LOGIN_ID 0x10000
/* #define SBP2_ORB_TIMEOUT 2000U /* Timeout in ms */
* 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_NULL 0x80000000 #define SBP2_ORB_NULL 0x80000000
#define SBP2_RETRY_LIMIT 0xf /* 15 retries */ #define SBP2_RETRY_LIMIT 0xf /* 15 retries */
#define SBP2_CYCLE_LIMIT (0xc8 << 12) /* 200 125us cycles */ #define SBP2_CYCLE_LIMIT (0xc8 << 12) /* 200 125us cycles */
@@ -1034,7 +1027,6 @@ static int sbp2_scan_unit_dir(struct sbp2_target *tgt, u32 *directory,
{ {
struct fw_csr_iterator ci; struct fw_csr_iterator ci;
int key, value; int key, value;
unsigned int timeout;
fw_csr_iterator_init(&ci, directory); fw_csr_iterator_init(&ci, directory);
while (fw_csr_iterator_next(&ci, &key, &value)) { while (fw_csr_iterator_next(&ci, &key, &value)) {
@@ -1059,17 +1051,7 @@ static int sbp2_scan_unit_dir(struct sbp2_target *tgt, u32 *directory,
case SBP2_CSR_UNIT_CHARACTERISTICS: case SBP2_CSR_UNIT_CHARACTERISTICS:
/* the timeout value is stored in 500ms units */ /* the timeout value is stored in 500ms units */
timeout = ((unsigned int) value >> 8 & 0xff) * 500; tgt->mgt_orb_timeout = (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);
break; break;
case SBP2_CSR_LOGICAL_UNIT_NUMBER: case SBP2_CSR_LOGICAL_UNIT_NUMBER:
@@ -1087,6 +1069,22 @@ static int sbp2_scan_unit_dir(struct sbp2_target *tgt, u32 *directory,
return 0; 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, static void sbp2_init_workarounds(struct sbp2_target *tgt, u32 model,
u32 firmware_revision) u32 firmware_revision)
{ {
@@ -1171,6 +1169,7 @@ static int sbp2_probe(struct device *dev)
&firmware_revision) < 0) &firmware_revision) < 0)
goto fail_tgt_put; goto fail_tgt_put;
sbp2_clamp_management_orb_timeout(tgt);
sbp2_init_workarounds(tgt, model, firmware_revision); sbp2_init_workarounds(tgt, model, firmware_revision);
/* /*