Merge remote-tracking branch 'remotes/pmaydell/tags/pull-target-arm-20161024' into staging

target-arm queue:
 * support variable (runtime-determined) page sizes, for a
   nearly-20% speedup of TCG for ARMv7 and v8 CPUs with 4K pages
 * ptimer: add tests, support more flexible behaviour around
   what happens on the "zero" tick, use ptimer for a9gtimer
 * virt: ACPI: Add IORT Structure definition
 * i2c: Fix SMBus read transactions to avoid double events
 * timer: stm32f2xx_timer: add check for prescaler value
 * QOMify musicpal, pxa2xx_gpio, strongarm, pl110
 * target-arm: Implement new HLT trap for semihosting
 * i2c: Add asserts for second smbus i2c_start_transfer()

# gpg: Signature made Mon 24 Oct 2016 18:24:17 BST
# gpg:                using RSA key 0x3C2525ED14360CDE
# gpg: Good signature from "Peter Maydell <peter.maydell@linaro.org>"
# gpg:                 aka "Peter Maydell <pmaydell@gmail.com>"
# gpg:                 aka "Peter Maydell <pmaydell@chiark.greenend.org.uk>"
# Primary key fingerprint: E1A5 C593 CD41 9DE2 8E83  15CF 3C25 25ED 1436 0CDE

* remotes/pmaydell/tags/pull-target-arm-20161024: (32 commits)
  i2c: Add asserts for second smbus i2c_start_transfer()
  target-arm: Implement new HLT trap for semihosting
  hw/display: QOM'ify pl110.c
  hw/arm: QOM'ify strongarm.c
  hw/arm: QOM'ify pxa2xx_gpio.c
  hw/arm: QOM'ify musicpal.c
  timer: stm32f2xx_timer: add check for prescaler value
  i2c: Fix SMBus read transactions to avoid double events
  timer: a9gtimer: remove loop to auto-increment comparator
  ARM: Virt: ACPI: Build an IORT table with RC and ITS nodes
  ACPI: Add IORT Structure definition
  tests: Add tests for the ARM MPTimer
  arm_mptimer: Convert to use ptimer
  tests: ptimer: Replace 10000 with 1
  tests: ptimer: Change the copyright comment
  tests: ptimer: Add tests for "no counter round down" policy
  hw/ptimer: Add "no counter round down" policy
  tests: ptimer: Add tests for "no immediate reload" policy
  hw/ptimer: Add "no immediate reload" policy
  tests: ptimer: Add tests for "no immediate trigger" policy
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 25 insertions, 14 deletions

diff --git a/hw/i2c/core.c b/hw/i2c/core.c
index 4afbe0bde5..abd4c4cddb 100644
--- a/hw/i2c/core.c
+++ b/hw/i2c/core.c
@@ -88,7 +88,12 @@ int i2c_bus_busy(I2CBus *bus)
     return !QLIST_EMPTY(&bus->current_devs);
 }
 
-/* Returns non-zero if the address is not valid.  */
+/*
+ * Returns non-zero if the address is not valid.  If this is called
+ * again without an intervening i2c_end_transfer(), like in the SMBus
+ * case where the operation is switched from write to read, this
+ * function will not rescan the bus and thus cannot fail.
+ */
 /* TODO: Make this handle multiple masters.  */
 int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
 {
@@ -104,15 +109,25 @@ int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
         bus->broadcast = true;
     }
 
-    QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
-        DeviceState *qdev = kid->child;
-        I2CSlave *candidate = I2C_SLAVE(qdev);
-        if ((candidate->address == address) || (bus->broadcast)) {
-            node = g_malloc(sizeof(struct I2CNode));
-            node->elt = candidate;
-            QLIST_INSERT_HEAD(&bus->current_devs, node, next);
-            if (!bus->broadcast) {
-                break;
+    /*
+     * If there are already devices in the list, that means we are in
+     * the middle of a transaction and we shouldn't rescan the bus.
+     *
+     * This happens with any SMBus transaction, even on a pure I2C
+     * device.  The interface does a transaction start without
+     * terminating the previous transaction.
+     */
+    if (QLIST_EMPTY(&bus->current_devs)) {
+        QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
+            DeviceState *qdev = kid->child;
+            I2CSlave *candidate = I2C_SLAVE(qdev);
+            if ((candidate->address == address) || (bus->broadcast)) {
+                node = g_malloc(sizeof(struct I2CNode));
+                node->elt = candidate;
+                QLIST_INSERT_HEAD(&bus->current_devs, node, next);
+                if (!bus->broadcast) {
+                    break;
+                }
             }
         }
     }
@@ -137,10 +152,6 @@ void i2c_end_transfer(I2CBus *bus)
     I2CSlaveClass *sc;
     I2CNode *node, *next;
 
-    if (QLIST_EMPTY(&bus->current_devs)) {
-        return;
-    }
-
     QLIST_FOREACH_SAFE(node, &bus->current_devs, next, next) {
         sc = I2C_SLAVE_GET_CLASS(node->elt);
         if (sc->event) {