[src/trunk]: src/sys/arch/arm/sunxi Serialize RSB requests.

[jmcneill <jmcneill%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/95fff94a4e9e
branches:  trunk
changeset: 445912:95fff94a4e9e
user:      jmcneill <jmcneill%NetBSD.org@localhost>
date:      Sat Nov 17 19:30:51 2018 +0000

description:
Serialize RSB requests.

diffstat:

 sys/arch/arm/sunxi/sunxi_rsb.c |  15 ++++++++++++---
 1 files changed, 12 insertions(+), 3 deletions(-)

diffs (57 lines):

diff -r dc60ed40f926 -r 95fff94a4e9e sys/arch/arm/sunxi/sunxi_rsb.c
--- a/sys/arch/arm/sunxi/sunxi_rsb.c    Sat Nov 17 19:22:48 2018 +0000
+++ b/sys/arch/arm/sunxi/sunxi_rsb.c    Sat Nov 17 19:30:51 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: sunxi_rsb.c,v 1.5 2018/07/16 23:11:47 christos Exp $ */
+/* $NetBSD: sunxi_rsb.c,v 1.6 2018/11/17 19:30:51 jmcneill Exp $ */
 
 /*-
  * Copyright (c) 2014-2017 Jared McNeill <jmcneill%invisible.ca@localhost>
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sunxi_rsb.c,v 1.5 2018/07/16 23:11:47 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sunxi_rsb.c,v 1.6 2018/11/17 19:30:51 jmcneill Exp $");
 
 #include <sys/param.h>
 #include <sys/bus.h>
@@ -90,6 +90,7 @@
        device_t sc_i2cdev;
        void *sc_ih;
        uint32_t sc_stat;
+       bool sc_busy;
 
        uint16_t sc_rsb_last_da;
 };
@@ -326,7 +327,13 @@
 {
        struct sunxi_rsb_softc *sc = priv;
 
-       mutex_enter(&sc->sc_lock);
+       for (;;) {
+               mutex_enter(&sc->sc_lock);
+               if (sc->sc_busy == false)
+                       break;
+               mutex_exit(&sc->sc_lock);
+       }
+       sc->sc_busy = true;
 
        return 0;
 }
@@ -336,6 +343,7 @@
 {
        struct sunxi_rsb_softc *sc = priv;
 
+       sc->sc_busy = false;
        mutex_exit(&sc->sc_lock);
 }
 
@@ -349,6 +357,7 @@
        int error, i;
 
        KASSERT(mutex_owned(&sc->sc_lock));
+       KASSERT(sc->sc_busy == true);
 
        if (cmdlen != 1 || (len != 1 && len != 2 && len != 4))
                return EINVAL;