powerpc/qe: add polling timeout to qe_issue_cmd()

The qe_issue_cmd() function (Freescale PowerPC QUICC Engine library) polls
on a register until a status bit changes, but does not include a timeout
to handle the situation if the bit never changes.  Change the code to use
the new spin_event_timeout() macro, which simplifies polling on a register
without a timeout.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

1 files changed, 6 insertions, 3 deletions

diff --git a/arch/powerpc/sysdev/qe_lib/qe.c b/arch/powerpc/sysdev/qe_lib/qe.c
index b28b0e512d67..237e3654f48c 100644
--- a/arch/powerpc/sysdev/qe_lib/qe.c
+++ b/arch/powerpc/sysdev/qe_lib/qe.c
@@ -112,6 +112,7 @@ int qe_issue_cmd(u32 cmd, u32 device, u8 mcn_protocol, u32 cmd_input)
 {
         unsigned long flags;
         u8 mcn_shift = 0, dev_shift = 0;
+        u32 ret;
 
         spin_lock_irqsave(&qe_lock, flags);
         if (cmd == QE_RESET) {
@@ -139,11 +140,13 @@ int qe_issue_cmd(u32 cmd, u32 device, u8 mcn_protocol, u32 cmd_input)
         }
 
         /* wait for the QE_CR_FLG to clear */
-        while(in_be32(&qe_immr->cp.cecr) & QE_CR_FLG)
-                cpu_relax();
+        ret = spin_event_timeout((in_be32(&qe_immr->cp.cecr) & QE_CR_FLG) == 0,
+                           100, 0);
+        /* On timeout (e.g. failure), the expression will be false (ret == 0),
+           otherwise it will be true (ret == 1). */
         spin_unlock_irqrestore(&qe_lock, flags);
 
-        return 0;
+        return ret == 1;
 }
 EXPORT_SYMBOL(qe_issue_cmd);