freebsd-dev/sys/kern/subr_firmware.c
Ian Dowse eb1030c4fd Keep firmware images on the list until they have been unregistered
with firmware_unregister(). Previously when the last driver reference
had been dropped we would clear the list entry under the assumption
that the firmware module was about to be unloaded, but this was not
true if the firmware image had been loaded manually with kldload.

This makes it possible to manually kldload firmware images as a
workaround for drivers such as ipw that attempt to load firmware
while resuming after a suspend.

Reviewed by:	mlaier (an earlier version of the patch)
2006-06-10 17:04:07 +00:00

287 lines
7.3 KiB
C

/*-
* Copyright (c) 2005, Sam Leffler <sam@errno.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/queue.h>
#include <sys/taskqueue.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/errno.h>
#include <sys/linker.h>
#include <sys/firmware.h>
#include <sys/proc.h>
#include <sys/module.h>
#define FIRMWARE_MAX 30
static struct firmware firmware_table[FIRMWARE_MAX];
struct task firmware_task;
struct mtx firmware_mtx;
MTX_SYSINIT(firmware, &firmware_mtx, "firmware table", MTX_DEF);
/*
* Register a firmware image with the specified name. The
* image name must not already be registered. If this is a
* subimage then parent refers to a previously registered
* image that this should be associated with.
*/
struct firmware *
firmware_register(const char *imagename, const void *data, size_t datasize,
unsigned int version, struct firmware *parent)
{
struct firmware *frp = NULL;
int i;
mtx_lock(&firmware_mtx);
for (i = 0; i < FIRMWARE_MAX; i++) {
struct firmware *fp = &firmware_table[i];
if (fp->name == NULL) {
if (frp == NULL)
frp = fp;
continue;
}
if (strcasecmp(imagename, fp->name) == 0) {
mtx_unlock(&firmware_mtx);
printf("%s: image %s already registered!\n",
__func__, imagename);
return NULL;
}
}
if (frp == NULL) {
mtx_unlock(&firmware_mtx);
printf("%s: cannot register image %s, firmware table full!\n",
__func__, imagename);
return NULL;
}
frp->name = imagename;
frp->data = data;
frp->datasize = datasize;
frp->version = version;
frp->refcnt = 0;
frp->flags = 0;
if (parent != NULL)
parent->refcnt++;
frp->parent = parent;
frp->file = NULL;
mtx_unlock(&firmware_mtx);
return frp;
}
static void
clearentry(struct firmware *fp)
{
KASSERT(fp->refcnt == 0, ("image %s refcnt %u", fp->name, fp->refcnt));
fp->name = NULL;
fp->file = NULL;
fp->data = NULL;
fp->datasize = 0;
fp->version = 0;
fp->flags = 0;
if (fp->parent != NULL) { /* release parent reference */
fp->parent->refcnt--;
fp->parent = NULL;
}
}
static struct firmware *
lookup(const char *name)
{
int i;
for (i = 0; i < FIRMWARE_MAX; i++) {
struct firmware * fp = &firmware_table[i];
if (fp->name != NULL && strcasecmp(name, fp->name) == 0)
return fp;
}
return NULL;
}
/*
* Unregister/remove a firmware image. If there are outstanding
* references an error is returned and the image is not removed
* from the registry.
*/
int
firmware_unregister(const char *imagename)
{
struct firmware *fp;
int refcnt = 0;
mtx_lock(&firmware_mtx);
/*
* NB: it is ok for the lookup to fail; this can happen
* when a module is unloaded on last reference and the
* module unload handler unregister's each of it's
* firmware images.
*/
fp = lookup(imagename);
if (fp != NULL) {
refcnt = fp->refcnt;
if (refcnt == 0)
clearentry(fp);
}
mtx_unlock(&firmware_mtx);
return (refcnt != 0 ? EBUSY : 0);
}
/*
* Lookup and potentially load the specified firmware image.
* If the firmware is not found in the registry attempt to
* load a kernel module with the image name. If the firmware
* is located a reference is returned. The caller must release
* this reference for the image to be eligible for removal/unload.
*/
struct firmware *
firmware_get(const char *imagename)
{
struct thread *td;
struct firmware *fp;
linker_file_t result;
int requested_load = 0;
again:
mtx_lock(&firmware_mtx);
fp = lookup(imagename);
if (fp != NULL) {
if (requested_load)
fp->file = result;
fp->refcnt++;
mtx_unlock(&firmware_mtx);
return fp;
}
/*
* Image not present, try to load the module holding it
* or if we already tried give up.
*/
mtx_unlock(&firmware_mtx);
if (requested_load) {
printf("%s: failed to load firmware image %s\n",
__func__, imagename);
return NULL;
}
td = curthread;
if (suser(td) != 0 || securelevel_gt(td->td_ucred, 0) != 0) {
printf("%s: insufficient privileges to "
"load firmware image %s\n", __func__, imagename);
return NULL;
}
mtx_lock(&Giant); /* XXX */
(void) linker_reference_module(imagename, NULL, &result);
mtx_unlock(&Giant); /* XXX */
requested_load = 1;
goto again; /* sort of an Algol-style for loop */
}
static void
unloadentry(void *unused1, int unused2)
{
struct firmware *fp;
linker_file_t file;
int i;
mtx_lock(&firmware_mtx);
for (;;) {
/* Look for an unwanted entry that we explicitly loaded. */
for (i = 0; i < FIRMWARE_MAX; i++) {
fp = &firmware_table[i];
if (fp->name != NULL && fp->file != NULL &&
fp->refcnt == 0 &&
(fp->flags & FIRMWAREFLAG_KEEPKLDREF) == 0)
break;
fp = NULL;
}
if (fp == NULL)
break;
file = fp->file;
/* No longer explicitly loaded. */
fp->file = NULL;
mtx_unlock(&firmware_mtx);
linker_file_unload(file, LINKER_UNLOAD_NORMAL);
mtx_lock(&firmware_mtx);
}
mtx_unlock(&firmware_mtx);
}
/*
* Release a reference to a firmware image returned by
* firmware_get. The reference is released and if this is
* the last reference to the firmware image the associated
* module may be released/unloaded.
*/
void
firmware_put(struct firmware *fp, int flags)
{
mtx_lock(&firmware_mtx);
fp->refcnt--;
if (fp->refcnt == 0) {
if ((flags & FIRMWARE_UNLOAD) == 0)
fp->flags |= FIRMWAREFLAG_KEEPKLDREF;
}
if (fp->file)
taskqueue_enqueue(taskqueue_thread, &firmware_task);
mtx_unlock(&firmware_mtx);
}
/*
* Module glue.
*/
static int
firmware_modevent(module_t mod, int type, void *unused)
{
int i;
switch (type) {
case MOD_LOAD:
TASK_INIT(&firmware_task, 0, unloadentry, NULL);
return 0;
case MOD_UNLOAD:
for (i = 0; i < FIRMWARE_MAX; i++) {
struct firmware *fp = &firmware_table[i];
fp->flags &= ~FIRMWAREFLAG_KEEPKLDREF;
}
taskqueue_enqueue(taskqueue_thread, &firmware_task);
taskqueue_drain(taskqueue_thread, &firmware_task);
return 0;
}
return EINVAL;
}
static moduledata_t firmware_mod = {
"firmware",
firmware_modevent,
0
};
DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
MODULE_VERSION(firmware, 1);