Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 9ef8617a authored by Dave Olson's avatar Dave Olson Committed by Roland Dreier
Browse files

IB/ipath: Correctly describe workaround for TID write chip bug 



This is a comment change, only, correcting the comment to match the
implemented workaround, rather than the original workaround, and
clarifying why it's needed.

Signed-off-by: default avatarDave Olson <dave.olson@qlogic.com>
Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent 1793b477

drivers/infiniband/hw/ipath/ipath_iba6120.c

+8 −5
Original line number Original line Diff line number Diff line
@@ -1143,11 +1143,14 @@ static void ipath_pe_put_tid(struct ipath_devdata *dd, u64 __iomem *tidptr, 
			pa |= 2 << 29;

			pa |= 2 << 29;

	}

	}





	/* workaround chip bug 9437 by writing each TID twice

	/*

	 * and holding a spinlock around the writes, so they don't

	 * Workaround chip bug 9437 by writing the scratch register

	 * intermix with other TID (eager or expected) writes

	 * before and after the TID, and with an io write barrier.

	 * Unfortunately, this call can be done from interrupt level

	 * We use a spinlock around the writes, so they can't intermix

	 * for the port 0 eager TIDs, so we have to use irqsave

	 * with other TID (eager or expected) writes (the chip bug

	 * is triggered by back to back TID writes). Unfortunately, this

	 * call can be done from interrupt level for the port 0 eager TIDs,

	 * so we have to use irqsave locks.

	 */

	 */

	spin_lock_irqsave(&dd->ipath_tid_lock, flags);

	spin_lock_irqsave(&dd->ipath_tid_lock, flags);

	ipath_write_kreg(dd, dd->ipath_kregs->kr_scratch, 0xfeeddeaf);

	ipath_write_kreg(dd, dd->ipath_kregs->kr_scratch, 0xfeeddeaf);