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Commit e1393667 authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Stefan Richter
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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: default avatarClemens Ladisch <clemens@ladisch.de>
Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
parent 2608203d

drivers/firewire/ohci.c

+13 −7
Original line number Diff line number Diff line
@@ -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));

					 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);



 out:

	fw_core_handle_response(&ohci->card, &response);

}