xemu/hw/core/qdev-clock.c
Markus Armbruster d2623129a7 qom: Drop parameter @errp of object_property_add() & friends
The only way object_property_add() can fail is when a property with
the same name already exists.  Since our property names are all
hardcoded, failure is a programming error, and the appropriate way to
handle it is passing &error_abort.

Same for its variants, except for object_property_add_child(), which
additionally fails when the child already has a parent.  Parentage is
also under program control, so this is a programming error, too.

We have a bit over 500 callers.  Almost half of them pass
&error_abort, slightly fewer ignore errors, one test case handles
errors, and the remaining few callers pass them to their own callers.

The previous few commits demonstrated once again that ignoring
programming errors is a bad idea.

Of the few ones that pass on errors, several violate the Error API.
The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.  ich9_pm_add_properties(), sparc32_ledma_realize(),
sparc32_dma_realize(), xilinx_axidma_realize(), xilinx_enet_realize()
are wrong that way.

When the one appropriate choice of argument is &error_abort, letting
users pick the argument is a bad idea.

Drop parameter @errp and assert the preconditions instead.

There's one exception to "duplicate property name is a programming
error": the way object_property_add() implements the magic (and
undocumented) "automatic arrayification".  Don't drop @errp there.
Instead, rename object_property_add() to object_property_try_add(),
and add the obvious wrapper object_property_add().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-15-armbru@redhat.com>
[Two semantic rebase conflicts resolved]
2020-05-15 07:07:58 +02:00

186 lines
4.7 KiB
C

/*
* Device's clock input and output
*
* Copyright GreenSocs 2016-2020
*
* Authors:
* Frederic Konrad
* Damien Hedde
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "hw/qdev-clock.h"
#include "hw/qdev-core.h"
#include "qapi/error.h"
/*
* qdev_init_clocklist:
* Add a new clock in a device
*/
static NamedClockList *qdev_init_clocklist(DeviceState *dev, const char *name,
bool output, Clock *clk)
{
NamedClockList *ncl;
/*
* Clock must be added before realize() so that we can compute the
* clock's canonical path during device_realize().
*/
assert(!dev->realized);
/*
* The ncl structure is freed by qdev_finalize_clocklist() which will
* be called during @dev's device_finalize().
*/
ncl = g_new0(NamedClockList, 1);
ncl->name = g_strdup(name);
ncl->output = output;
ncl->alias = (clk != NULL);
/*
* Trying to create a clock whose name clashes with some other
* clock or property is a bug in the caller and we will abort().
*/
if (clk == NULL) {
clk = CLOCK(object_new(TYPE_CLOCK));
object_property_add_child(OBJECT(dev), name, OBJECT(clk));
if (output) {
/*
* Remove object_new()'s initial reference.
* Note that for inputs, the reference created by object_new()
* will be deleted in qdev_finalize_clocklist().
*/
object_unref(OBJECT(clk));
}
} else {
object_property_add_link(OBJECT(dev), name,
object_get_typename(OBJECT(clk)),
(Object **) &ncl->clock,
NULL, OBJ_PROP_LINK_STRONG);
}
ncl->clock = clk;
QLIST_INSERT_HEAD(&dev->clocks, ncl, node);
return ncl;
}
void qdev_finalize_clocklist(DeviceState *dev)
{
/* called by @dev's device_finalize() */
NamedClockList *ncl, *ncl_next;
QLIST_FOREACH_SAFE(ncl, &dev->clocks, node, ncl_next) {
QLIST_REMOVE(ncl, node);
if (!ncl->output && !ncl->alias) {
/*
* We kept a reference on the input clock to ensure it lives up to
* this point so we can safely remove the callback.
* It avoids having a callback to a deleted object if ncl->clock
* is still referenced somewhere else (eg: by a clock output).
*/
clock_clear_callback(ncl->clock);
object_unref(OBJECT(ncl->clock));
}
g_free(ncl->name);
g_free(ncl);
}
}
Clock *qdev_init_clock_out(DeviceState *dev, const char *name)
{
NamedClockList *ncl;
assert(name);
ncl = qdev_init_clocklist(dev, name, true, NULL);
return ncl->clock;
}
Clock *qdev_init_clock_in(DeviceState *dev, const char *name,
ClockCallback *callback, void *opaque)
{
NamedClockList *ncl;
assert(name);
ncl = qdev_init_clocklist(dev, name, false, NULL);
if (callback) {
clock_set_callback(ncl->clock, callback, opaque);
}
return ncl->clock;
}
void qdev_init_clocks(DeviceState *dev, const ClockPortInitArray clocks)
{
const struct ClockPortInitElem *elem;
for (elem = &clocks[0]; elem->name != NULL; elem++) {
Clock **clkp;
/* offset cannot be inside the DeviceState part */
assert(elem->offset > sizeof(DeviceState));
clkp = (Clock **)(((void *) dev) + elem->offset);
if (elem->is_output) {
*clkp = qdev_init_clock_out(dev, elem->name);
} else {
*clkp = qdev_init_clock_in(dev, elem->name, elem->callback, dev);
}
}
}
static NamedClockList *qdev_get_clocklist(DeviceState *dev, const char *name)
{
NamedClockList *ncl;
QLIST_FOREACH(ncl, &dev->clocks, node) {
if (strcmp(name, ncl->name) == 0) {
return ncl;
}
}
return NULL;
}
Clock *qdev_get_clock_in(DeviceState *dev, const char *name)
{
NamedClockList *ncl;
assert(name);
ncl = qdev_get_clocklist(dev, name);
assert(!ncl->output);
return ncl->clock;
}
Clock *qdev_get_clock_out(DeviceState *dev, const char *name)
{
NamedClockList *ncl;
assert(name);
ncl = qdev_get_clocklist(dev, name);
assert(ncl->output);
return ncl->clock;
}
Clock *qdev_alias_clock(DeviceState *dev, const char *name,
DeviceState *alias_dev, const char *alias_name)
{
NamedClockList *ncl;
assert(name && alias_name);
ncl = qdev_get_clocklist(dev, name);
qdev_init_clocklist(alias_dev, alias_name, ncl->output, ncl->clock);
return ncl->clock;
}