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author | Ben Collins <bcollins@ubuntu.com> | 2006-06-12 18:12:37 -0400 |
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committer | Ben Collins <bcollins@ubuntu.com> | 2006-06-12 18:12:37 -0400 |
commit | 647dcb5fae0ebb5da1272ed2773df0d3f152c303 (patch) | |
tree | 31d6a6ab3fd8acb2dc9335dfa181972f4433158a /drivers/ieee1394/nodemgr.c | |
parent | 57fdb58fa5a140bdd52cf4c4ffc30df73676f0a5 (diff) | |
download | kernel_samsung_smdk4412-647dcb5fae0ebb5da1272ed2773df0d3f152c303.zip kernel_samsung_smdk4412-647dcb5fae0ebb5da1272ed2773df0d3f152c303.tar.gz kernel_samsung_smdk4412-647dcb5fae0ebb5da1272ed2773df0d3f152c303.tar.bz2 |
ieee1394: support for slow links or slow 1394b phy ports
Add support for the following types of hardware:
+ nodes that have a link speed < PHY speed
+ 1394b PHYs that are less than S800 capable
+ 1394b/1394a adapter cable between two 1394b PHYs
Also, S1600 and S3200 are now supported if IEEE1394_SPEED_MAX is raised.
A probing function is added to nodemgr's config ROM fetching routine
which adjusts the allowable speed if an access problem was encountered.
Pros and Cons of the approach:
+ minimum code footprint to support this less widely used hardware
+ nearly no overhead for unaffected hardware
- ineffective before nodemgr began to read the ROM of affected nodes
- ineffective if ieee1394 is loaded with disable_nodemgr=1
The speed map CSRs which are published to the bus are not touched by the
patch.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Hakan Ardo <hakan@debian.org>
Cc: Calculex <linux@calculex.com>
Cc: Robert J. Kosinski <robk@cmcherald.com>
Signed-off-by: Ben Collins <bcollins@ubuntu.com>
Diffstat (limited to 'drivers/ieee1394/nodemgr.c')
-rw-r--r-- | drivers/ieee1394/nodemgr.c | 61 |
1 files changed, 58 insertions, 3 deletions
diff --git a/drivers/ieee1394/nodemgr.c b/drivers/ieee1394/nodemgr.c index 082c7fd..948f1b8 100644 --- a/drivers/ieee1394/nodemgr.c +++ b/drivers/ieee1394/nodemgr.c @@ -38,6 +38,7 @@ struct nodemgr_csr_info { struct hpsb_host *host; nodeid_t nodeid; unsigned int generation; + unsigned int speed_unverified:1; }; @@ -57,23 +58,75 @@ static char *nodemgr_find_oui_name(int oui) return NULL; } +/* + * Correct the speed map entry. This is necessary + * - for nodes with link speed < phy speed, + * - for 1394b nodes with negotiated phy port speed < IEEE1394_SPEED_MAX. + * A possible speed is determined by trial and error, using quadlet reads. + */ +static int nodemgr_check_speed(struct nodemgr_csr_info *ci, u64 addr, + quadlet_t *buffer) +{ + quadlet_t q; + u8 i, *speed, old_speed, good_speed; + int ret; + + speed = ci->host->speed + NODEID_TO_NODE(ci->nodeid); + old_speed = *speed; + good_speed = IEEE1394_SPEED_MAX + 1; + + /* Try every speed from S100 to old_speed. + * If we did it the other way around, a too low speed could be caught + * if the retry succeeded for some other reason, e.g. because the link + * just finished its initialization. */ + for (i = IEEE1394_SPEED_100; i <= old_speed; i++) { + *speed = i; + ret = hpsb_read(ci->host, ci->nodeid, ci->generation, addr, + &q, sizeof(quadlet_t)); + if (ret) + break; + *buffer = q; + good_speed = i; + } + if (good_speed <= IEEE1394_SPEED_MAX) { + HPSB_DEBUG("Speed probe of node " NODE_BUS_FMT " yields %s", + NODE_BUS_ARGS(ci->host, ci->nodeid), + hpsb_speedto_str[good_speed]); + *speed = good_speed; + ci->speed_unverified = 0; + return 0; + } + *speed = old_speed; + return ret; +} static int nodemgr_bus_read(struct csr1212_csr *csr, u64 addr, u16 length, void *buffer, void *__ci) { struct nodemgr_csr_info *ci = (struct nodemgr_csr_info*)__ci; - int i, ret = 0; + int i, ret; for (i = 1; ; i++) { ret = hpsb_read(ci->host, ci->nodeid, ci->generation, addr, buffer, length); - if (!ret || i == 3) + if (!ret) { + ci->speed_unverified = 0; + break; + } + /* Give up after 3rd failure. */ + if (i == 3) break; + /* The ieee1394_core guessed the node's speed capability from + * the self ID. Check whether a lower speed works. */ + if (ci->speed_unverified && length == sizeof(quadlet_t)) { + ret = nodemgr_check_speed(ci, addr, buffer); + if (!ret) + break; + } if (msleep_interruptible(334)) return -EINTR; } - return ret; } @@ -1204,6 +1257,8 @@ static void nodemgr_node_scan_one(struct host_info *hi, ci->host = host; ci->nodeid = nodeid; ci->generation = generation; + ci->speed_unverified = + host->speed[NODEID_TO_NODE(nodeid)] > IEEE1394_SPEED_100; /* We need to detect when the ConfigROM's generation has changed, * so we only update the node's info when it needs to be. */ |