firewire: ohci: wait for local CSR lock access to finish (e1393667) · Commits · 戴 / test

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>

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);
		}

Admin message