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[Qemu-devel] [PATCH 12/15] qdev: document reset semantics
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 12/15] qdev: document reset semantics |
Date: |
Mon, 17 Dec 2012 17:24:47 +0100 |
Signed-off-by: Paolo Bonzini <address@hidden>
---
hw/qdev-core.h | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 50 insertions(+), 1 deletion(-)
diff --git a/hw/qdev-core.h b/hw/qdev-core.h
index 28f12a4..1274994 100644
--- a/hw/qdev-core.h
+++ b/hw/qdev-core.h
@@ -36,7 +36,24 @@ typedef struct DeviceClass {
Property *props;
int no_user;
- /* callbacks */
+ /* reset:
+ * @dev: Device being reset.
+ *
+ * Performs the device-specific part of a device-level ("soft") reset
+ * of @dev. This is called by QEMU internally as part of initialization
+ * or resetting a bus, but it is often accessible using a device register
+ * as well. Devices can access it using qdev_reset_all.
+ *
+ * In general, a soft reset will not reset any state that depends on the
+ * type of bus that the device resides on. For example, PCI devices do not
+ * reset their base address registers or configuration space in the reset
+ * callback. Resetting these registers is handled by the bus, not by the
+ * device.
+ *
+ * A device-level reset also includes a hard reset of all the buses exposed
+ * by @dev (and all devices below those, recursively). However, this is
+ * handled by qdev_reset_all and this callback need not care about it.
+ */
void (*reset)(DeviceState *dev);
/* device state */
@@ -86,6 +103,23 @@ struct BusClass {
* bindings can be found at http://playground.sun.com/1275/bindings/.
*/
char *(*get_fw_dev_path)(DeviceState *dev);
+
+ /* reset:
+ * @bus: Bus being reset.
+ *
+ * This callback performs a reset of @bus. It is usually done when
+ * qdev_reset_all is called on the parent of @bus.
+ *
+ * Resetting a bus includes a bus-level ("hard") reset of all devices on
+ * the bus itself. Compared to a device-level ("soft") reset, this will
+ * also remove all the configuration for devices. In the case of PCI, for
+ * example, this means the base address registers, configuration space,
+ * etc.
+ *
+ * The callback may take care of calling qdev_reset_all on all devices
+ * to perform the soft reset, or not. In the first case, it should return
+ * 1; in the second case, it should return 0 (see also qbus_walkerfn).
+ */
int (*reset)(BusState *bus);
};
@@ -186,6 +220,21 @@ int qdev_walk_children(DeviceState *dev,
qdev_walkerfn *post_devfn, qbus_walkerfn *post_busfn,
void *opaque);
+/**
+ * @qdev_reset_all:
+ * @dev: Device to be reset.
+ *
+ * Perform a device-level ("soft") reset of dev, including all buses
+ * and all devices connected to those buses. A soft reset means that
+ * qdev_reset_all will not reset any state that depends on the type of
+ * bus that the device resides on. For example, PCI devices will not
+ * reset their base address registers or configuration space.
+ *
+ * However, this is not true for device connected to @dev's buses; these are
+ * reset completely. For example, if @dev is a PCI-to-PCI bridge, the base
+ * address registers will be reset for devices on the bridge, but not for @dev
+ * itself.
+ */
void qdev_reset_all(DeviceState *dev);
/**
--
1.8.0.2
- [Qemu-devel] [PATCH 10/15] qdev: switch reset to post-order, (continued)
- [Qemu-devel] [PATCH 10/15] qdev: switch reset to post-order, Paolo Bonzini, 2012/12/17
- [Qemu-devel] [PATCH 11/15] qdev: remove device_reset, Paolo Bonzini, 2012/12/17
- [Qemu-devel] [PATCH 15/15] virtio-serial: do not perform bus reset by hand, Paolo Bonzini, 2012/12/17
- [Qemu-devel] [PATCH 14/15] virtio-s390: reset all qbuses too when writing to the status field, Paolo Bonzini, 2012/12/17
- [Qemu-devel] [PATCH 13/15] virtio-pci: reset all qbuses too when writing to the status field, Paolo Bonzini, 2012/12/17
[Qemu-devel] [PATCH 12/15] qdev: document reset semantics,
Paolo Bonzini <=
Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Michael S. Tsirkin, 2012/12/17