diff options
| author | Clemens Ladisch <clemens@ladisch.de> | 2010-04-12 10:35:44 +0200 |
|---|---|---|
| committer | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2010-04-19 19:58:32 +0200 |
| commit | e1393667be574807a13bfaf1bb471f5fd1a5287b (patch) | |
| tree | 5f2084f1a5099062cb27e74765ec3cd8a69c3489 | |
| parent | firewire: ohci: prevent aliasing of locally handled register addresses (diff) | |
| download | linux-e1393667be574807a13bfaf1bb471f5fd1a5287b.tar.xz linux-e1393667be574807a13bfaf1bb471f5fd1a5287b.zip | |
firewire: ohci: wait for local CSR lock access to finish
Add a loop to wait for the controller to finish a locally-initiated CSR
lock operation. Google shows some occurrences of the "swap not done
yet" message which might indicate that some OHCI controllers are not
fast enough to do the lock/swap in the time needed for one PCI access.
This also correctly handles the case where the lock operation did not
finish, instead of silently returning an uninitialized value.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
| -rw-r--r-- | drivers/firewire/ohci.c | 20 |
1 files changed, 13 insertions, 7 deletions
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c index 82fb2e7e99ef..6e95f8fb56db 100644 --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -1158,7 +1158,7 @@ static void handle_local_lock(struct fw_ohci *ohci, struct fw_packet *packet, u32 csr) { struct fw_packet response; - int tcode, length, ext_tcode, sel; + int tcode, length, ext_tcode, sel, try; __be32 *payload, lock_old; u32 lock_arg, lock_data; @@ -1185,13 +1185,19 @@ static void handle_local_lock(struct fw_ohci *ohci, reg_write(ohci, OHCI1394_CSRCompareData, lock_arg); reg_write(ohci, OHCI1394_CSRControl, sel); - if (reg_read(ohci, OHCI1394_CSRControl) & 0x80000000) - lock_old = cpu_to_be32(reg_read(ohci, OHCI1394_CSRData)); - else - fw_notify("swap not done yet\n"); + for (try = 0; try < 20; try++) + if (reg_read(ohci, OHCI1394_CSRControl) & 0x80000000) { + lock_old = cpu_to_be32(reg_read(ohci, + OHCI1394_CSRData)); + fw_fill_response(&response, packet->header, + RCODE_COMPLETE, + &lock_old, sizeof(lock_old)); + goto out; + } + + fw_error("swap not done (CSR lock timeout)\n"); + fw_fill_response(&response, packet->header, RCODE_BUSY, NULL, 0); - fw_fill_response(&response, packet->header, - RCODE_COMPLETE, &lock_old, sizeof(lock_old)); out: fw_core_handle_response(&ohci->card, &response); } |