firmware: Import from FreeBSD.

freebsd/sys/kern/subr_firmware.c

@@ -0,0 +1,528 @@
+#include <machine/rtems-bsd-kernel-space.h>
+
+/*-
+ * Copyright (c) 2005-2008, 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 <rtems/bsd/sys/param.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/queue.h>
+#include <sys/taskqueue.h>
+#include <sys/systm.h>
+#include <rtems/bsd/sys/lock.h>
+#include <sys/mutex.h>
+#include <rtems/bsd/sys/errno.h>
+#include <sys/linker.h>
+#include <sys/firmware.h>
+#include <sys/priv.h>
+#include <sys/proc.h>
+#include <sys/module.h>
+#include <sys/eventhandler.h>
+
+#include <sys/filedesc.h>
+#include <sys/vnode.h>
+
+/*
+ * Loadable firmware support. See sys/sys/firmware.h and firmware(9)
+ * form more details on the subsystem.
+ *
+ * 'struct firmware' is the user-visible part of the firmware table.
+ * Additional internal information is stored in a 'struct priv_fw'
+ * (currently a static array). A slot is in use if FW_INUSE is true:
+ */
+
+#define FW_INUSE(p)	((p)->file != NULL || (p)->fw.name != NULL)
+
+/*
+ * fw.name != NULL when an image is registered; file != NULL for
+ * autoloaded images whose handling has not been completed.
+ *
+ * The state of a slot evolves as follows:
+ *	firmware_register	-->  fw.name = image_name
+ *	(autoloaded image)	-->  file = module reference
+ *	firmware_unregister	-->  fw.name = NULL
+ *	(unloadentry complete)	-->  file = NULL
+ *
+ * In order for the above to work, the 'file' field must remain
+ * unchanged in firmware_unregister().
+ *
+ * Images residing in the same module are linked to each other
+ * through the 'parent' argument of firmware_register().
+ * One image (typically, one with the same name as the module to let
+ * the autoloading mechanism work) is considered the parent image for
+ * all other images in the same module. Children affect the refcount
+ * on the parent image preventing improper unloading of the image itself.
+ */
+
+struct priv_fw {
+	int		refcnt;		/* reference count */
+
+	/*
+	 * parent entry, see above. Set on firmware_register(),
+	 * cleared on firmware_unregister().
+	 */
+	struct priv_fw	*parent;
+
+	int 		flags;	/* record FIRMWARE_UNLOAD requests */
+#define FW_UNLOAD	0x100
+
+	/*
+	 * 'file' is private info managed by the autoload/unload code.
+	 * Set at the end of firmware_get(), cleared only in the
+	 * firmware_unload_task, so the latter can depend on its value even
+	 * while the lock is not held.
+	 */
+	linker_file_t   file;	/* module file, if autoloaded */
+
+	/*
+	 * 'fw' is the externally visible image information.
+	 * We do not make it the first field in priv_fw, to avoid the
+	 * temptation of casting pointers to each other.
+	 * Use PRIV_FW(fw) to get a pointer to the cointainer of fw.
+	 * Beware, PRIV_FW does not work for a NULL pointer.
+	 */
+	struct firmware	fw;	/* externally visible information */
+};
+
+/*
+ * PRIV_FW returns the pointer to the container of struct firmware *x.
+ * Cast to intptr_t to override the 'const' attribute of x
+ */
+#define PRIV_FW(x)	((struct priv_fw *)		\
+	((intptr_t)(x) - offsetof(struct priv_fw, fw)) )
+
+/*
+ * At the moment we use a static array as backing store for the registry.
+ * Should we move to a dynamic structure, keep in mind that we cannot
+ * reallocate the array because pointers are held externally.
+ * A list may work, though.
+ */
+#define	FIRMWARE_MAX	50
+static struct priv_fw firmware_table[FIRMWARE_MAX];
+
+/*
+ * Firmware module operations are handled in a separate task as they
+ * might sleep and they require directory context to do i/o.
+ */
+static struct taskqueue *firmware_tq;
+static struct task firmware_unload_task;
+
+/*
+ * This mutex protects accesses to the firmware table.
+ */
+static struct mtx firmware_mtx;
+MTX_SYSINIT(firmware, &firmware_mtx, "firmware table", MTX_DEF);
+
+/*
+ * Helper function to lookup a name.
+ * As a side effect, it sets the pointer to a free slot, if any.
+ * This way we can concentrate most of the registry scanning in
+ * this function, which makes it easier to replace the registry
+ * with some other data structure.
+ */
+static struct priv_fw *
+lookup(const char *name, struct priv_fw **empty_slot)
+{
+	struct priv_fw *fp = NULL;
+	struct priv_fw *dummy;
+	int i;
+
+	if (empty_slot == NULL)
+		empty_slot = &dummy;
+	*empty_slot = NULL;
+	for (i = 0; i < FIRMWARE_MAX; i++) {
+		fp = &firmware_table[i];
+		if (fp->fw.name != NULL && strcasecmp(name, fp->fw.name) == 0)
+			break;
+		else if (!FW_INUSE(fp))
+			*empty_slot = fp;
+	}
+	return (i < FIRMWARE_MAX ) ? fp : NULL;
+}
+
+/*
+ * 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.
+ */
+const struct firmware *
+firmware_register(const char *imagename, const void *data, size_t datasize,
+    unsigned int version, const struct firmware *parent)
+{
+	struct priv_fw *match, *frp;
+	char *str;
+
+	str = strdup(imagename, M_TEMP);
+
+	mtx_lock(&firmware_mtx);
+	/*
+	 * Do a lookup to make sure the name is unique or find a free slot.
+	 */
+	match = lookup(imagename, &frp);
+	if (match != NULL) {
+		mtx_unlock(&firmware_mtx);
+		printf("%s: image %s already registered!\n",
+			__func__, imagename);
+		free(str, M_TEMP);
+		return NULL;
+	}
+	if (frp == NULL) {
+		mtx_unlock(&firmware_mtx);
+		printf("%s: cannot register image %s, firmware table full!\n",
+		    __func__, imagename);
+		free(str, M_TEMP);
+		return NULL;
+	}
+	bzero(frp, sizeof(*frp));	/* start from a clean record */
+	frp->fw.name = str;
+	frp->fw.data = data;
+	frp->fw.datasize = datasize;
+	frp->fw.version = version;
+	if (parent != NULL)
+		frp->parent = PRIV_FW(parent);
+	mtx_unlock(&firmware_mtx);
+	if (bootverbose)
+		printf("firmware: '%s' version %u: %zu bytes loaded at %p\n",
+		    imagename, version, datasize, data);
+	return &frp->fw;
+}
+
+/*
+ * 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 priv_fw *fp;
+	int err;
+
+	mtx_lock(&firmware_mtx);
+	fp = lookup(imagename, NULL);
+	if (fp == NULL) {
+		/*
+		 * 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 its
+		 * firmware images.
+		 */
+		err = 0;
+	} else if (fp->refcnt != 0) {	/* cannot unregister */
+		err = EBUSY;
+	} else {
+		linker_file_t x = fp->file;	/* save value */
+
+		/*
+		 * Clear the whole entry with bzero to make sure we
+		 * do not forget anything. Then restore 'file' which is
+		 * non-null for autoloaded images.
+		 */
+		free((void *) (uintptr_t) fp->fw.name, M_TEMP);
+		bzero(fp, sizeof(struct priv_fw));
+		fp->file = x;
+		err = 0;
+	}
+	mtx_unlock(&firmware_mtx);
+	return err;
+}
+
+static void
+loadimage(void *arg, int npending)
+{
+	struct thread *td = curthread;
+	char *imagename = arg;
+	struct priv_fw *fp;
+	linker_file_t result;
+	int error;
+
+	/* synchronize with the thread that dispatched us */
+	mtx_lock(&firmware_mtx);
+	mtx_unlock(&firmware_mtx);
+
+	if (td->td_proc->p_fd->fd_rdir == NULL) {
+		printf("%s: root not mounted yet, no way to load image\n",
+		    imagename);
+		goto done;
+	}
+	error = linker_reference_module(imagename, NULL, &result);
+	if (error != 0) {
+		printf("%s: could not load firmware image, error %d\n",
+		    imagename, error);
+		goto done;
+	}
+
+	mtx_lock(&firmware_mtx);
+	fp = lookup(imagename, NULL);
+	if (fp == NULL || fp->file != NULL) {
+		mtx_unlock(&firmware_mtx);
+		if (fp == NULL)
+			printf("%s: firmware image loaded, "
+			    "but did not register\n", imagename);
+		(void) linker_release_module(imagename, NULL, NULL);
+		goto done;
+	}
+	fp->file = result;	/* record the module identity */
+	mtx_unlock(&firmware_mtx);
+done:
+	wakeup_one(imagename);		/* we're done */
+}
+
+/*
+ * Lookup and potentially load the specified firmware image.
+ * If the firmware is not found in the registry, try to load a kernel
+ * module named as 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.
+ */
+const struct firmware *
+firmware_get(const char *imagename)
+{
+	struct task fwload_task;
+	struct thread *td;
+	struct priv_fw *fp;
+
+	mtx_lock(&firmware_mtx);
+	fp = lookup(imagename, NULL);
+	if (fp != NULL)
+		goto found;
+	/*
+	 * Image not present, try to load the module holding it.
+	 */
+	td = curthread;
+	if (priv_check(td, PRIV_FIRMWARE_LOAD) != 0 ||
+	    securelevel_gt(td->td_ucred, 0) != 0) {
+		mtx_unlock(&firmware_mtx);
+		printf("%s: insufficient privileges to "
+		    "load firmware image %s\n", __func__, imagename);
+		return NULL;
+	}
+	/* 
+	 * Defer load to a thread with known context.  linker_reference_module
+	 * may do filesystem i/o which requires root & current dirs, etc.
+	 * Also we must not hold any mtx's over this call which is problematic.
+	 */
+	if (!cold) {
+		TASK_INIT(&fwload_task, 0, loadimage, __DECONST(void *,
+		    imagename));
+		taskqueue_enqueue(firmware_tq, &fwload_task);
+		msleep(__DECONST(void *, imagename), &firmware_mtx, 0,
+		    "fwload", 0);
+	}
+	/*
+	 * After attempting to load the module, see if the image is registered.
+	 */
+	fp = lookup(imagename, NULL);
+	if (fp == NULL) {
+		mtx_unlock(&firmware_mtx);
+		return NULL;
+	}
+found:				/* common exit point on success */
+	if (fp->refcnt == 0 && fp->parent != NULL)
+		fp->parent->refcnt++;
+	fp->refcnt++;
+	mtx_unlock(&firmware_mtx);
+	return &fp->fw;
+}
+
+/*
+ * Release a reference to a firmware image returned by firmware_get.
+ * The caller may specify, with the FIRMWARE_UNLOAD flag, its desire
+ * to release the resource, but the flag is only advisory.
+ *
+ * If this is the last reference to the firmware image, and this is an
+ * autoloaded module, wake up the firmware_unload_task to figure out
+ * what to do with the associated module.
+ */
+void
+firmware_put(const struct firmware *p, int flags)
+{
+	struct priv_fw *fp = PRIV_FW(p);
+
+	mtx_lock(&firmware_mtx);
+	fp->refcnt--;
+	if (fp->refcnt == 0) {
+		if (fp->parent != NULL)
+			fp->parent->refcnt--;
+		if (flags & FIRMWARE_UNLOAD)
+			fp->flags |= FW_UNLOAD;
+		if (fp->file)
+			taskqueue_enqueue(firmware_tq, &firmware_unload_task);
+	}
+	mtx_unlock(&firmware_mtx);
+}
+
+/*
+ * Setup directory state for the firmware_tq thread so we can do i/o.
+ */
+static void
+set_rootvnode(void *arg, int npending)
+{
+
+	pwd_ensure_dirs();
+
+	free(arg, M_TEMP);
+}
+
+/*
+ * Event handler called on mounting of /; bounce a task
+ * into the task queue thread to setup it's directories.
+ */
+static void
+firmware_mountroot(void *arg)
+{
+	struct task *setroot_task;
+
+	setroot_task = malloc(sizeof(struct task), M_TEMP, M_NOWAIT);
+	if (setroot_task != NULL) {
+		TASK_INIT(setroot_task, 0, set_rootvnode, setroot_task);
+		taskqueue_enqueue(firmware_tq, setroot_task);
+	} else
+		printf("%s: no memory for task!\n", __func__);
+}
+EVENTHANDLER_DEFINE(mountroot, firmware_mountroot, NULL, 0);
+
+/*
+ * The body of the task in charge of unloading autoloaded modules
+ * that are not needed anymore.
+ * Images can be cross-linked so we may need to make multiple passes,
+ * but the time we spend in the loop is bounded because we clear entries
+ * as we touch them.
+ */
+static void
+unloadentry(void *unused1, int unused2)
+{
+	int limit = FIRMWARE_MAX;
+	int i;	/* current cycle */
+
+	mtx_lock(&firmware_mtx);
+	/*
+	 * Scan the table. limit is set to make sure we make another
+	 * full sweep after matching an entry that requires unloading.
+	 */
+	for (i = 0; i < limit; i++) {
+		struct priv_fw *fp;
+		int err;
+
+		fp = &firmware_table[i % FIRMWARE_MAX];
+		if (fp->fw.name == NULL || fp->file == NULL ||
+		    fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0)
+			continue;
+
+		/*
+		 * Found an entry. Now:
+		 * 1. bump up limit to make sure we make another full round;
+		 * 2. clear FW_UNLOAD so we don't try this entry again.
+		 * 3. release the lock while trying to unload the module.
+		 * 'file' remains set so that the entry cannot be reused
+		 * in the meantime (it also means that fp->file will
+		 * not change while we release the lock).
+		 */
+		limit = i + FIRMWARE_MAX;	/* make another full round */
+		fp->flags &= ~FW_UNLOAD;	/* do not try again */
+
+		mtx_unlock(&firmware_mtx);
+		err = linker_release_module(NULL, NULL, fp->file);
+		mtx_lock(&firmware_mtx);
+
+		/*
+		 * We rely on the module to call firmware_unregister()
+		 * on unload to actually release the entry.
+		 * If err = 0 we can drop our reference as the system
+		 * accepted it. Otherwise unloading failed (e.g. the
+		 * module itself gave an error) so our reference is
+		 * still valid.
+		 */
+		if (err == 0)
+			fp->file = NULL; 
+	}
+	mtx_unlock(&firmware_mtx);
+}
+
+/*
+ * Module glue.
+ */
+static int
+firmware_modevent(module_t mod, int type, void *unused)
+{
+	struct priv_fw *fp;
+	int i, err;
+
+	switch (type) {
+	case MOD_LOAD:
+		TASK_INIT(&firmware_unload_task, 0, unloadentry, NULL);
+		firmware_tq = taskqueue_create("taskqueue_firmware", M_WAITOK,
+		    taskqueue_thread_enqueue, &firmware_tq);
+		/* NB: use our own loop routine that sets up context */
+		(void) taskqueue_start_threads(&firmware_tq, 1, PWAIT,
+		    "firmware taskq");
+		if (rootvnode != NULL) {
+			/* 
+			 * Root is already mounted so we won't get an event;
+			 * simulate one here.
+			 */
+			firmware_mountroot(NULL);
+		}
+		return 0;
+
+	case MOD_UNLOAD:
+		/* request all autoloaded modules to be released */
+		mtx_lock(&firmware_mtx);
+		for (i = 0; i < FIRMWARE_MAX; i++) {
+			fp = &firmware_table[i];
+			fp->flags |= FW_UNLOAD;
+		}
+		mtx_unlock(&firmware_mtx);
+		taskqueue_enqueue(firmware_tq, &firmware_unload_task);
+		taskqueue_drain(firmware_tq, &firmware_unload_task);
+		err = 0;
+		for (i = 0; i < FIRMWARE_MAX; i++) {
+			fp = &firmware_table[i];
+			if (fp->fw.name != NULL) {
+				printf("%s: image %p ref %d still active slot %d\n",
+					__func__, fp->fw.name,
+					fp->refcnt,  i);
+				err = EINVAL;
+			}
+		}
+		if (err == 0)
+			taskqueue_free(firmware_tq);
+		return err;
+	}
+	return EINVAL;
+}
+
+static moduledata_t firmware_mod = {
+	"firmware",
+	firmware_modevent,
+	NULL
+};
+DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
+MODULE_VERSION(firmware, 1);

freebsd/sys/sys/firmware.h

@@ -0,0 +1,64 @@
+/*-
+ * 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.
+ *
+ * $FreeBSD$
+ */
+#ifndef _SYS_FIRMWARE_H_
+#define _SYS_FIRMWARE_H_
+/*
+ * Loadable firmware support.
+ *
+ * The firmware abstraction provides an interface for loading firmware
+ * images into the kernel and making them available to clients.
+ *
+ * Firmware images are usually embedded in kernel loadable modules that can
+ * be loaded on-demand or pre-loaded as desired.  Modules may contain
+ * one or more firmware images that are stored as opaque data arrays
+ * and registered with a unique string name. Clients request
+ * firmware by name, and are returned a struct firmware * below on success.
+ * The kernel keeps track of references to firmware images to allow/prevent
+ * module/data unload.
+ *
+ * When multiple images are stored in one module, the first image is
+ * treated as the master with the other images holding references
+ * to it.  This means that to unload the module each dependent/subimage
+ * must first have its references removed.
+ * In order for automatic loading to work, the master image must have
+ * the same name as the module it is embedded into.
+ */
+struct firmware {
+	const char	*name;		/* system-wide name */
+	const void	*data;		/* location of image */
+	size_t		 datasize;	/* size of image in bytes */
+	unsigned int	 version;	/* version of the image */
+};
+
+const struct firmware	*firmware_register(const char *,
+	const void *, size_t, unsigned int, const struct firmware *);
+int	 firmware_unregister(const char *);
+const struct firmware *firmware_get(const char *);
+#define	FIRMWARE_UNLOAD		0x0001	/* unload if unreferenced */
+void		 firmware_put(const struct firmware *, int);
+#endif /* _SYS_FIRMWARE_H_ */