hw/sd: add card-reparenting function

Provide a new function sdbus_reparent_card() in sd core for reparenting
a card from a SDBus to another one.

This function is required by the raspi platform, where the two SD
controllers can be dynamically switched.

Signed-off-by: Clement Deschamps <clement.deschamps@antfield.fr>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1488293711-14195-3-git-send-email-peter.maydell@linaro.org
Message-id: 20170224164021.9066-3-clement.deschamps@antfield.fr
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: added a doc comment to the header file; changed to
 use new behaviour of qdev_set_parent_bus()]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 27 insertions, 0 deletions

diff --git a/hw/sd/core.c b/hw/sd/core.c
index 14c2bdf27b..295dc44ab7 100644
--- a/hw/sd/core.c
+++ b/hw/sd/core.c
@@ -131,6 +131,33 @@ void sdbus_set_readonly(SDBus *sdbus, bool readonly)
     }
 }
 
+void sdbus_reparent_card(SDBus *from, SDBus *to)
+{
+    SDState *card = get_card(from);
+    SDCardClass *sc;
+    bool readonly;
+
+    /* We directly reparent the card object rather than implementing this
+     * as a hotpluggable connection because we don't want to expose SD cards
+     * to users as being hotpluggable, and we can get away with it in this
+     * limited use case. This could perhaps be implemented more cleanly in
+     * future by adding support to the hotplug infrastructure for "device
+     * can be hotplugged only via code, not by user".
+     */
+
+    if (!card) {
+        return;
+    }
+
+    sc = SD_CARD_GET_CLASS(card);
+    readonly = sc->get_readonly(card);
+
+    sdbus_set_inserted(from, false);
+    qdev_set_parent_bus(DEVICE(card), &to->qbus);
+    sdbus_set_inserted(to, true);
+    sdbus_set_readonly(to, readonly);
+}
+
 static const TypeInfo sd_bus_info = {
     .name = TYPE_SD_BUS,
     .parent = TYPE_BUS,