Adding upstream version 2.10.0+dfsg.upstream/2.10.0+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

8 files changed, 1645 insertions, 0 deletions

diff --git a/lib/debugfs/blobs.h b/lib/debugfs/blobs.h
new file mode 100644
index 0000000..54ca9f7
--- /dev/null
+++ b/lib/debugfs/blobs.h
@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2019, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include "dev.h"
+
+static const dirtab_t blobtab[] = {
+	{"ctl", DEV_ROOT_QBLOBCTL, 0, O_READ},
+	{"fip.bin", DEV_ROOT_QBLOBCTL + 1, 0x100000, O_READ, (void *)0x8000000}
+};
diff --git a/lib/debugfs/debugfs.mk b/lib/debugfs/debugfs.mk
new file mode 100644
index 0000000..caa9fcf
--- /dev/null
+++ b/lib/debugfs/debugfs.mk
@@ -0,0 +1,13 @@
+#
+# Copyright (c) 2019, Arm Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+DEBUGFS_SRCS	:=	$(addprefix lib/debugfs/,	\
+			dev.c				\
+			devc.c				\
+			devroot.c			\
+			devfip.c)
+
+DEBUGFS_SRCS    += lib/debugfs/debugfs_smc.c
diff --git a/lib/debugfs/debugfs_smc.c b/lib/debugfs/debugfs_smc.c
new file mode 100644
index 0000000..64c64f8
--- /dev/null
+++ b/lib/debugfs/debugfs_smc.c
@@ -0,0 +1,209 @@
+/*
+ * Copyright (c) 2019, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include <lib/debugfs.h>
+#include <lib/smccc.h>
+#include <lib/spinlock.h>
+#include <lib/xlat_tables/xlat_tables_v2.h>
+#include <smccc_helpers.h>
+
+#define MAX_PATH_LEN	256
+
+#define MOUNT		0
+#define CREATE		1
+#define OPEN		2
+#define CLOSE		3
+#define READ		4
+#define WRITE		5
+#define SEEK		6
+#define BIND		7
+#define STAT		8
+#define INIT		10
+#define VERSION		11
+
+/* This is the virtual address to which we map the NS shared buffer */
+#define DEBUGFS_SHARED_BUF_VIRT		((void *)0x81000000U)
+
+static union debugfs_parms {
+	struct {
+		char fname[MAX_PATH_LEN];
+	} open;
+
+	struct {
+		char srv[MAX_PATH_LEN];
+		char where[MAX_PATH_LEN];
+		char spec[MAX_PATH_LEN];
+	} mount;
+
+	struct {
+		char path[MAX_PATH_LEN];
+		dir_t dir;
+	} stat;
+
+	struct {
+		char oldpath[MAX_PATH_LEN];
+		char newpath[MAX_PATH_LEN];
+	} bind;
+} parms;
+
+/* debugfs_access_lock protects shared buffer and internal */
+/* FS functions from concurrent accesses.                 */
+static spinlock_t debugfs_access_lock;
+
+static bool debugfs_initialized;
+
+uintptr_t debugfs_smc_handler(unsigned int smc_fid,
+			      u_register_t cmd,
+			      u_register_t arg2,
+			      u_register_t arg3,
+			      u_register_t arg4,
+			      void *cookie,
+			      void *handle,
+			      u_register_t flags)
+{
+	int64_t smc_ret = DEBUGFS_E_INVALID_PARAMS, smc_resp = 0;
+	int ret;
+
+	/* Allow calls from non-secure only */
+	if (is_caller_secure(flags)) {
+		SMC_RET1(handle, DEBUGFS_E_DENIED);
+	}
+
+	/* Expect a SiP service fast call */
+	if ((GET_SMC_TYPE(smc_fid) != SMC_TYPE_FAST) ||
+		(GET_SMC_OEN(smc_fid) != OEN_SIP_START)) {
+		SMC_RET1(handle, SMC_UNK);
+	}
+
+	/* Truncate parameters if 32b SMC convention call */
+	if (GET_SMC_CC(smc_fid) == SMC_32) {
+		arg2 &= 0xffffffff;
+		arg3 &= 0xffffffff;
+		arg4 &= 0xffffffff;
+	}
+
+	spin_lock(&debugfs_access_lock);
+
+	if (debugfs_initialized == true) {
+		/* Copy NS shared buffer to internal secure location */
+		memcpy(&parms, (void *)DEBUGFS_SHARED_BUF_VIRT,
+		       sizeof(union debugfs_parms));
+	}
+
+	switch (cmd) {
+	case INIT:
+		if (debugfs_initialized == false) {
+			/* TODO: check PA validity e.g. whether */
+			/* it is an NS region.                  */
+			ret = mmap_add_dynamic_region(arg2,
+				(uintptr_t)DEBUGFS_SHARED_BUF_VIRT,
+				PAGE_SIZE_4KB,
+				MT_MEMORY | MT_RW | MT_NS);
+			if (ret == 0) {
+				debugfs_initialized = true;
+				smc_ret = SMC_OK;
+				smc_resp = 0;
+			}
+		}
+		break;
+
+	case VERSION:
+		smc_ret = SMC_OK;
+		smc_resp = DEBUGFS_VERSION;
+		break;
+
+	case MOUNT:
+		ret = mount(parms.mount.srv,
+			    parms.mount.where,
+			    parms.mount.spec);
+		if (ret == 0) {
+			smc_ret = SMC_OK;
+			smc_resp = 0;
+		}
+		break;
+
+	case OPEN:
+		ret = open(parms.open.fname, arg2);
+		if (ret >= 0) {
+			smc_ret = SMC_OK;
+			smc_resp = ret;
+		}
+		break;
+
+	case CLOSE:
+		ret = close(arg2);
+		if (ret == 0) {
+			smc_ret = SMC_OK;
+			smc_resp = 0;
+		}
+		break;
+
+	case READ:
+		ret = read(arg2, DEBUGFS_SHARED_BUF_VIRT, arg3);
+		if (ret >= 0) {
+			smc_ret = SMC_OK;
+			smc_resp = ret;
+		}
+		break;
+
+	case SEEK:
+		ret = seek(arg2, arg3, arg4);
+		if (ret == 0) {
+			smc_ret = SMC_OK;
+			smc_resp = 0;
+		}
+		break;
+
+	case BIND:
+		ret = bind(parms.bind.oldpath, parms.bind.newpath);
+		if (ret == 0) {
+			smc_ret = SMC_OK;
+			smc_resp = 0;
+		}
+		break;
+
+	case STAT:
+		ret = stat(parms.stat.path, &parms.stat.dir);
+		if (ret == 0) {
+			memcpy((void *)DEBUGFS_SHARED_BUF_VIRT, &parms,
+			       sizeof(union debugfs_parms));
+			smc_ret = SMC_OK;
+			smc_resp = 0;
+		}
+		break;
+
+	/* Not implemented */
+	case CREATE:
+		/* Intentional fall-through */
+
+	/* Not implemented */
+	case WRITE:
+		/* Intentional fall-through */
+
+	default:
+		smc_ret = SMC_UNK;
+		smc_resp = 0;
+	}
+
+	spin_unlock(&debugfs_access_lock);
+
+	SMC_RET2(handle, smc_ret, smc_resp);
+
+	/* Not reached */
+	return smc_ret;
+}
+
+int debugfs_smc_setup(void)
+{
+	debugfs_initialized = false;
+	debugfs_access_lock.lock = 0;
+
+	return 0;
+}
diff --git a/lib/debugfs/dev.c b/lib/debugfs/dev.c
new file mode 100644
index 0000000..2fc1d40
--- /dev/null
+++ b/lib/debugfs/dev.c
@@ -0,0 +1,853 @@
+/*
+ * Copyright (c) 2019-2021, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <cdefs.h>
+#include <common/debug.h>
+#include <lib/debugfs.h>
+#include <string.h>
+
+#include "dev.h"
+
+#define NR_MOUNT_POINTS		4
+
+struct mount_point {
+	chan_t	*new;
+	chan_t	*old;
+};
+
+/* This array contains all the available channels of the filesystem.
+ * A file descriptor is the index of a specific channel in this array.
+ */
+static chan_t fdset[NR_CHANS];
+
+/* This array contains all the available mount points of the filesystem. */
+static struct mount_point mount_points[NR_MOUNT_POINTS];
+
+/* This variable stores the channel associated to the root directory. */
+static chan_t slash_channel;
+
+/* This function creates a channel from a device index and registers
+ * it to fdset.
+ */
+static chan_t *create_new_channel(unsigned char index)
+{
+	chan_t *channel = NULL;
+	int i;
+
+	for (i = 0; i < NR_CHANS; i++) {
+		if (fdset[i].index == NODEV) {
+			channel = &fdset[i];
+			channel->index = index;
+			break;
+		}
+	}
+
+	return channel;
+}
+
+/*******************************************************************************
+ * This function returns a pointer to an existing channel in fdset from a file
+ * descriptor.
+ ******************************************************************************/
+static chan_t *fd_to_channel(int fd)
+{
+	if ((fd < 0) || (fd >= NR_CHANS) || (fdset[fd].index == NODEV)) {
+		return NULL;
+	}
+
+	return &fdset[fd];
+}
+
+/*******************************************************************************
+ * This function returns a file descriptor from a channel.
+ * The caller must be sure that the channel is registered in fdset.
+ ******************************************************************************/
+static int channel_to_fd(chan_t *channel)
+{
+	return (channel == NULL) ? -1 : (channel - fdset);
+}
+
+/*******************************************************************************
+ * This function checks the validity of a mode.
+ ******************************************************************************/
+static bool is_valid_mode(int mode)
+{
+	if ((mode & O_READ) && (mode & (O_WRITE | O_RDWR))) {
+		return false;
+	}
+	if ((mode & O_WRITE) && (mode & (O_READ | O_RDWR))) {
+		return false;
+	}
+	if ((mode & O_RDWR) && (mode & (O_READ | O_WRITE))) {
+		return false;
+	}
+
+	return true;
+}
+
+/*******************************************************************************
+ * This function extracts the next part of the given path contained and puts it
+ * in token. It returns a pointer to the remainder of the path.
+ ******************************************************************************/
+static const char *next(const char *path, char *token)
+{
+	int index;
+	const char *cursor;
+
+	while (*path == '/') {
+		++path;
+	}
+
+	index = 0;
+	cursor = path;
+	if (*path != '\0') {
+		while (*cursor != '/' && *cursor != '\0') {
+			if (index == NAMELEN) {
+				return NULL;
+			}
+			token[index++] = *cursor++;
+		}
+	}
+	token[index] = '\0';
+
+	return cursor;
+}
+
+/*******************************************************************************
+ * This function returns the driver index in devtab of the driver
+ * identified by id.
+ ******************************************************************************/
+static int get_device_index(int id)
+{
+	int index;
+	dev_t * const *dp;
+
+	for (index = 0, dp = devtab; *dp && (*dp)->id != id; ++dp) {
+		index++;
+	}
+
+	if (*dp == NULL) {
+		return -1;
+	}
+
+	return index;
+}
+
+/*******************************************************************************
+ * This function clears a given channel fields
+ ******************************************************************************/
+static void channel_clear(chan_t *channel)
+{
+	channel->offset = 0;
+	channel->qid    = 0;
+	channel->index  = NODEV;
+	channel->dev    = 0;
+	channel->mode   = 0;
+}
+
+/*******************************************************************************
+ * This function closes the channel pointed to by c.
+ ******************************************************************************/
+void channel_close(chan_t *channel)
+{
+	if (channel != NULL) {
+		channel_clear(channel);
+	}
+}
+
+/*******************************************************************************
+ * This function copies data from src to dst after applying the offset of the
+ * channel c. nbytes bytes are expected to be copied unless the data goes over
+ * dst + len.
+ * It returns the actual number of bytes that were copied.
+ ******************************************************************************/
+int buf_to_channel(chan_t *channel, void *dst, void *src, int nbytes, long len)
+{
+	const char *addr = src;
+
+	if ((channel == NULL) || (dst == NULL) || (src == NULL)) {
+		return 0;
+	}
+
+	if (channel->offset >= len) {
+		return 0;
+	}
+
+	if ((channel->offset + nbytes) > len) {
+		nbytes = len - channel->offset;
+	}
+
+	memcpy(dst, addr + channel->offset, nbytes);
+
+	channel->offset += nbytes;
+
+	return nbytes;
+}
+
+/*******************************************************************************
+ * This function checks whether a channel (identified by its device index and
+ * qid) is registered as a mount point.
+ * Returns a pointer to the channel it is mounted to when found, NULL otherwise.
+ ******************************************************************************/
+static chan_t *mount_point_to_channel(int index, qid_t qid)
+{
+	chan_t *channel;
+	struct mount_point *mp;
+
+	for (mp = mount_points; mp < &mount_points[NR_MOUNT_POINTS]; mp++) {
+		channel = mp->new;
+		if (channel == NULL) {
+			continue;
+		}
+
+		if ((channel->index == index) && (channel->qid == qid)) {
+			return mp->old;
+		}
+	}
+
+	return NULL;
+}
+
+/*******************************************************************************
+ * This function calls the attach function of the driver identified by id.
+ ******************************************************************************/
+chan_t *attach(int id, int dev)
+{
+	/* Get the devtab index for the driver identified by id */
+	int index = get_device_index(id);
+
+	if (index < 0) {
+		return NULL;
+	}
+
+	return devtab[index]->attach(id, dev);
+}
+
+/*******************************************************************************
+ * This function is the default implementation of the driver attach function.
+ * It creates a new channel and returns a pointer to it.
+ ******************************************************************************/
+chan_t *devattach(int id, int dev)
+{
+	chan_t *channel;
+	int index;
+
+	index = get_device_index(id);
+	if (index < 0) {
+		return NULL;
+	}
+
+	channel = create_new_channel(index);
+	if (channel == NULL) {
+		return NULL;
+	}
+
+	channel->dev = dev;
+	channel->qid = CHDIR;
+
+	return channel;
+}
+
+/*******************************************************************************
+ * This function returns a channel given a path.
+ * It goes through the filesystem, from the root namespace ('/') or from a
+ * device namespace ('#'), switching channel on mount points.
+ ******************************************************************************/
+chan_t *path_to_channel(const char *path, int mode)
+{
+	int i, n;
+	const char *path_next;
+	chan_t *mnt, *channel;
+	char elem[NAMELEN];
+
+	if (path == NULL) {
+		return NULL;
+	}
+
+	switch (path[0]) {
+	case '/':
+		channel = clone(&slash_channel, NULL);
+		path_next = path;
+		break;
+	case '#':
+		path_next = next(path + 1, elem);
+		if (path_next == NULL) {
+			goto noent;
+		}
+
+		n = 0;
+		for (i = 1; (elem[i] >= '0') && (elem[i] <= '9'); i++) {
+			n += elem[i] - '0';
+		}
+
+		if (elem[i] != '\0') {
+			goto noent;
+		}
+
+		channel = attach(elem[0], n);
+		break;
+	default:
+		return NULL;
+	}
+
+	if (channel == NULL) {
+		return NULL;
+	}
+
+	for (path_next = next(path_next, elem); *elem;
+			path_next = next(path_next, elem)) {
+		if ((channel->qid & CHDIR) == 0) {
+			goto notfound;
+		}
+
+		if (devtab[channel->index]->walk(channel, elem) < 0) {
+			channel_close(channel);
+			goto notfound;
+		}
+
+		mnt = mount_point_to_channel(channel->index, channel->qid);
+		if (mnt != NULL) {
+			clone(mnt, channel);
+		}
+	}
+
+	if (path_next == NULL) {
+		goto notfound;
+	}
+
+	/* TODO: check mode */
+	return channel;
+
+notfound:
+	channel_close(channel);
+noent:
+	return NULL;
+}
+
+/*******************************************************************************
+ * This function calls the clone function of the driver associated to the
+ * channel c.
+ ******************************************************************************/
+chan_t *clone(chan_t *c, chan_t *nc)
+{
+	if (c->index == NODEV) {
+		return NULL;
+	}
+
+	return devtab[c->index]->clone(c, nc);
+}
+
+/*******************************************************************************
+ * This function is the default implementation of the driver clone function.
+ * It creates a new channel and returns a pointer to it.
+ * It clones channel into new_channel.
+ ******************************************************************************/
+chan_t *devclone(chan_t *channel, chan_t *new_channel)
+{
+	if (channel == NULL) {
+		return NULL;
+	}
+
+	if (new_channel == NULL) {
+		new_channel = create_new_channel(channel->index);
+		if (new_channel == NULL) {
+			return NULL;
+		}
+	}
+
+	new_channel->qid    = channel->qid;
+	new_channel->dev    = channel->dev;
+	new_channel->mode   = channel->mode;
+	new_channel->offset = channel->offset;
+	new_channel->index  = channel->index;
+
+	return new_channel;
+}
+
+/*******************************************************************************
+ * This function is the default implementation of the driver walk function.
+ * It goes through all the elements of tab using the gen function until a match
+ * is found with name.
+ * If a match is found, it copies the qid of the new directory.
+ ******************************************************************************/
+int devwalk(chan_t *channel, const char *name, const dirtab_t *tab,
+	    int ntab, devgen_t *gen)
+{
+	int i;
+	dir_t dir;
+
+	if ((channel == NULL) || (name == NULL) || (gen == NULL)) {
+		return -1;
+	}
+
+	if ((name[0] == '.') && (name[1] == '\0')) {
+		return 1;
+	}
+
+	for (i = 0; ; i++) {
+		switch ((*gen)(channel, tab, ntab, i, &dir)) {
+		case 0:
+			/* Intentional fall-through */
+		case -1:
+			return -1;
+		case 1:
+			if (strncmp(name, dir.name, NAMELEN) != 0) {
+				continue;
+			}
+			channel->qid = dir.qid;
+			return 1;
+		}
+	}
+}
+
+/*******************************************************************************
+ * This is a helper function which exposes the content of a directory, element
+ * by element. It is meant to be called until the end of the directory is
+ * reached or an error occurs.
+ * It returns -1 on error, 0 on end of directory and 1 when a new file is found.
+ ******************************************************************************/
+int dirread(chan_t *channel, dir_t *dir, const dirtab_t *tab,
+	int ntab, devgen_t *gen)
+{
+	int i, ret;
+
+	if ((channel == NULL) || (dir == NULL) || (gen == NULL)) {
+		return -1;
+	}
+
+	i = channel->offset/sizeof(dir_t);
+	ret = (*gen)(channel, tab, ntab, i, dir);
+	if (ret == 1) {
+		channel->offset += sizeof(dir_t);
+	}
+
+	return ret;
+}
+
+/*******************************************************************************
+ * This function sets the elements of dir.
+ ******************************************************************************/
+void make_dir_entry(chan_t *channel, dir_t *dir,
+	     const char *name, long length, qid_t qid, unsigned int mode)
+{
+	if ((channel == NULL) || (dir == NULL) || (name == NULL)) {
+		return;
+	}
+
+	strlcpy(dir->name, name, sizeof(dir->name));
+	dir->length = length;
+	dir->qid = qid;
+	dir->mode = mode;
+
+	if ((qid & CHDIR) != 0) {
+		dir->mode |= O_DIR;
+	}
+
+	dir->index = channel->index;
+	dir->dev   = channel->dev;
+}
+
+/*******************************************************************************
+ * This function is the default implementation of the internal driver gen
+ * function.
+ * It copies and formats the information of the nth element of tab into dir.
+ ******************************************************************************/
+int devgen(chan_t *channel, const dirtab_t *tab, int ntab, int n, dir_t *dir)
+{
+	const dirtab_t *dp;
+
+	if ((channel == NULL) || (dir == NULL) || (tab == NULL) ||
+			(n >= ntab)) {
+		return 0;
+	}
+
+	dp = &tab[n];
+	make_dir_entry(channel, dir, dp->name, dp->length, dp->qid, dp->perm);
+	return 1;
+}
+
+/*******************************************************************************
+ * This function returns a file descriptor identifying the channel associated to
+ * the given path.
+ ******************************************************************************/
+int open(const char *path, int mode)
+{
+	chan_t *channel;
+
+	if (path == NULL) {
+		return -1;
+	}
+
+	if (is_valid_mode(mode) == false) {
+		return -1;
+	}
+
+	channel = path_to_channel(path, mode);
+
+	return channel_to_fd(channel);
+}
+
+/*******************************************************************************
+ * This function closes the channel identified by the file descriptor fd.
+ ******************************************************************************/
+int close(int fd)
+{
+	chan_t *channel;
+
+	channel = fd_to_channel(fd);
+	if (channel == NULL) {
+		return -1;
+	}
+
+	channel_close(channel);
+	return 0;
+}
+
+/*******************************************************************************
+ * This function is the default implementation of the driver stat function.
+ * It goes through all the elements of tab using the gen function until a match
+ * is found with file.
+ * If a match is found, dir contains the information file.
+ ******************************************************************************/
+int devstat(chan_t *dirc, const char *file, dir_t *dir,
+	    const dirtab_t *tab, int ntab, devgen_t *gen)
+{
+	int i, r = 0;
+	chan_t *c, *mnt;
+
+	if ((dirc == NULL) || (dir == NULL) || (gen == NULL)) {
+		return -1;
+	}
+
+	c = path_to_channel(file, O_STAT);
+	if (c == NULL) {
+		return -1;
+	}
+
+	for (i = 0; ; i++) {
+		switch ((*gen)(dirc, tab, ntab, i, dir)) {
+		case 0:
+			/* Intentional fall-through */
+		case -1:
+			r = -1;
+			goto leave;
+		case 1:
+			mnt = mount_point_to_channel(dir->index, dir->qid);
+			if (mnt != NULL) {
+				dir->qid = mnt->qid;
+				dir->index = mnt->index;
+			}
+
+			if ((dir->qid != c->qid) || (dir->index != c->index)) {
+				continue;
+			}
+
+			goto leave;
+		}
+	}
+
+leave:
+	channel_close(c);
+	return r;
+}
+
+/*******************************************************************************
+ * This function calls the stat function of the driver associated to the parent
+ * directory of the file in path.
+ * The result is stored in dir.
+ ******************************************************************************/
+int stat(const char *path, dir_t *dir)
+{
+	int r;
+	size_t len;
+	chan_t *channel;
+	char *p, dirname[PATHLEN];
+
+	if ((path == NULL) || (dir == NULL)) {
+		return -1;
+	}
+
+	len = strlen(path);
+	if ((len + 1) > sizeof(dirname)) {
+		return -1;
+	}
+
+	memcpy(dirname, path, len);
+	for (p = dirname + len; p > dirname; --p) {
+		if (*p != '/') {
+			break;
+		}
+	}
+
+	p = memrchr(dirname, '/', p - dirname);
+	if (p == NULL) {
+		return -1;
+	}
+
+	dirname[p - dirname + 1] = '\0';
+
+	channel = path_to_channel(dirname, O_STAT);
+	if (channel == NULL) {
+		return -1;
+	}
+
+	r = devtab[channel->index]->stat(channel, path, dir);
+	channel_close(channel);
+
+	return r;
+}
+
+/*******************************************************************************
+ * This function calls the read function of the driver associated to fd.
+ * It fills buf with at most n bytes.
+ * It returns the number of bytes that were actually read.
+ ******************************************************************************/
+int read(int fd, void *buf, int n)
+{
+	chan_t *channel;
+
+	if (buf == NULL) {
+		return -1;
+	}
+
+	channel = fd_to_channel(fd);
+	if (channel == NULL) {
+		return -1;
+	}
+
+	if (((channel->qid & CHDIR) != 0) && (n < sizeof(dir_t))) {
+		return -1;
+	}
+
+	return devtab[channel->index]->read(channel, buf, n);
+}
+
+/*******************************************************************************
+ * This function calls the write function of the driver associated to fd.
+ * It writes at most n bytes of buf.
+ * It returns the number of bytes that were actually written.
+ ******************************************************************************/
+int write(int fd, void *buf, int n)
+{
+	chan_t *channel;
+
+	if (buf == NULL) {
+		return -1;
+	}
+
+	channel = fd_to_channel(fd);
+	if (channel == NULL) {
+		return -1;
+	}
+
+	if ((channel->qid & CHDIR) != 0) {
+		return -1;
+	}
+
+	return devtab[channel->index]->write(channel, buf, n);
+}
+
+/*******************************************************************************
+ * This function calls the seek function of the driver associated to fd.
+ * It applies the offset off according to the strategy whence.
+ ******************************************************************************/
+int seek(int fd, long off, int whence)
+{
+	chan_t *channel;
+
+	channel = fd_to_channel(fd);
+	if (channel == NULL) {
+		return -1;
+	}
+
+	if ((channel->qid & CHDIR) != 0) {
+		return -1;
+	}
+
+	return devtab[channel->index]->seek(channel, off, whence);
+}
+
+/*******************************************************************************
+ * This function is the default error implementation of the driver mount
+ * function.
+ ******************************************************************************/
+chan_t *deverrmount(chan_t *channel, const char *spec)
+{
+	return NULL;
+}
+
+/*******************************************************************************
+ * This function is the default error implementation of the driver write
+ * function.
+ ******************************************************************************/
+int deverrwrite(chan_t *channel, void *buf, int n)
+{
+	return -1;
+}
+
+/*******************************************************************************
+ * This function is the default error implementation of the driver seek
+ * function.
+ ******************************************************************************/
+int deverrseek(chan_t *channel, long off, int whence)
+{
+	return -1;
+}
+
+/*******************************************************************************
+ * This function is the default implementation of the driver seek function.
+ * It applies the offset off according to the strategy whence to the channel c.
+ ******************************************************************************/
+int devseek(chan_t *channel, long off, int whence)
+{
+	switch (whence) {
+	case KSEEK_SET:
+		channel->offset = off;
+		break;
+	case KSEEK_CUR:
+		channel->offset += off;
+		break;
+	case KSEEK_END:
+		/* Not implemented */
+		return -1;
+	}
+
+	return 0;
+}
+
+/*******************************************************************************
+ * This function registers the channel associated to the path new as a mount
+ * point for the channel c.
+ ******************************************************************************/
+static int add_mount_point(chan_t *channel, const char *new)
+{
+	int i;
+	chan_t *cn;
+	struct mount_point *mp;
+
+	if (new == NULL) {
+		goto err0;
+	}
+
+	cn = path_to_channel(new, O_READ);
+	if (cn == NULL) {
+		goto err0;
+	}
+
+	if ((cn->qid & CHDIR) == 0) {
+		goto err1;
+	}
+
+	for (i = NR_MOUNT_POINTS - 1; i >= 0; i--) {
+		mp = &mount_points[i];
+		if (mp->new == NULL) {
+			break;
+		}
+	}
+
+	if (i < 0) {
+		goto err1;
+	}
+
+	mp->new = cn;
+	mp->old = channel;
+
+	return 0;
+
+err1:
+	channel_close(cn);
+err0:
+	return -1;
+}
+
+/*******************************************************************************
+ * This function registers the path new as a mount point for the path old.
+ ******************************************************************************/
+int bind(const char *old, const char *new)
+{
+	chan_t *channel;
+
+	channel = path_to_channel(old, O_BIND);
+	if (channel == NULL) {
+		return -1;
+	}
+
+	if (add_mount_point(channel, new) < 0) {
+		channel_close(channel);
+		return -1;
+	}
+
+	return 0;
+}
+
+/*******************************************************************************
+ * This function calls the mount function of the driver associated to the path
+ * srv.
+ * It mounts the path srv on the path where.
+ ******************************************************************************/
+int mount(const char *srv, const char *where, const char *spec)
+{
+	chan_t *channel, *mount_point_chan;
+	int ret;
+
+	channel = path_to_channel(srv, O_RDWR);
+	if (channel == NULL) {
+		goto err0;
+	}
+
+	mount_point_chan = devtab[channel->index]->mount(channel, spec);
+	if (mount_point_chan == NULL) {
+		goto err1;
+	}
+
+	ret = add_mount_point(mount_point_chan, where);
+	if (ret < 0) {
+		goto err2;
+	}
+
+	channel_close(channel);
+
+	return 0;
+
+err2:
+	channel_close(mount_point_chan);
+err1:
+	channel_close(channel);
+err0:
+	return -1;
+}
+
+/*******************************************************************************
+ * This function initializes the device environment.
+ * It creates the '/' channel.
+ * It links the device drivers to the physical drivers.
+ ******************************************************************************/
+void debugfs_init(void)
+{
+	chan_t *channel, *cloned_channel;
+
+	for (channel = fdset; channel < &fdset[NR_CHANS]; channel++) {
+		channel_clear(channel);
+	}
+
+	channel = devattach('/', 0);
+	if (channel == NULL) {
+		panic();
+	}
+
+	cloned_channel = clone(channel, &slash_channel);
+	if (cloned_channel == NULL) {
+		panic();
+	}
+
+	channel_close(channel);
+	devlink();
+}
+
+__dead2 void devpanic(const char *cause)
+{
+	panic();
+}
diff --git a/lib/debugfs/dev.h b/lib/debugfs/dev.h
new file mode 100644
index 0000000..c142651
--- /dev/null
+++ b/lib/debugfs/dev.h
@@ -0,0 +1,120 @@
+/*
+ * Copyright (c) 2019, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef DEV_H
+#define DEV_H
+
+#include <cdefs.h>
+#include <lib/debugfs.h>
+#include <stddef.h>
+
+/* FIXME: need configurability */
+#define NR_CHANS  10
+#define NR_CONSS  1
+#define NR_BINDS  4
+#define NR_FILES  18
+
+#define NODEV     255
+#define CHDIR     (1 << 15)
+
+#define SYNCDEV   0
+#define SYNCALL   1
+
+typedef struct dev dev_t;
+typedef struct chan chan_t;
+typedef struct dirtab dirtab_t;
+typedef int devgen_t(chan_t *, const dirtab_t *, int, int, dir_t *);
+typedef struct attr attr_t;
+
+enum {
+	DEV_ROOT_QROOT,
+	DEV_ROOT_QDEV,
+	DEV_ROOT_QFIP,
+	DEV_ROOT_QBLOBS,
+	DEV_ROOT_QBLOBCTL,
+	DEV_ROOT_QPSCI
+};
+
+/*******************************************************************************
+ * This structure contains the necessary information to represent a directory
+ * of the filesystem.
+ ******************************************************************************/
+struct dirtab {
+	char		name[NAMELEN];
+	qid_t		qid;
+	long		length;
+	unsigned char	perm;
+	void		*data;
+};
+
+/*******************************************************************************
+ * This structure defines the interface of device drivers.
+ * Each driver must implement a subset of those functions.
+ * It is possible to redirect to default implementations defined in dev.c.
+ ******************************************************************************/
+/* FIXME: comments for the callbacks */
+struct dev {
+	char id;
+	int (*stat)(chan_t *c, const char *file, dir_t *dir);
+	int (*walk)(chan_t *c, const char *name);
+	int (*read)(chan_t *c, void *buf, int n);
+	int (*write)(chan_t *c, void *buf, int n);
+	int (*seek)(chan_t *c, long off, int whence);
+	chan_t *(*clone)(chan_t *c, chan_t *nc);
+	chan_t *(*attach)(int id, int dev);
+	chan_t *(*mount)(chan_t *c, const char *spec);
+};
+
+/*******************************************************************************
+ * This structure defines the channel structure.
+ * A channel is a handle on an element of the filesystem.
+ ******************************************************************************/
+struct chan {
+	long		offset;
+	qid_t		qid;
+	unsigned char	index;	/* device index in devtab */
+	unsigned char	dev;
+	unsigned char	mode;
+};
+
+/*******************************************************************************
+ * This structure defines an abstract argument passed to physical drivers from
+ * the configuration file.
+ ******************************************************************************/
+struct attr {
+	char	*key;
+	char	*value;
+};
+
+chan_t *path_to_channel(const char *path, int mode);
+chan_t *clone(chan_t *c, chan_t *nc);
+chan_t *attach(int id, int dev);
+void channel_close(chan_t *c);
+int buf_to_channel(chan_t *c, void *dst, void *src, int nbytes, long len);
+int dirread(chan_t *c, dir_t *dir, const dirtab_t *tab,
+	    int ntab, devgen_t *gen);
+void make_dir_entry(chan_t *c, dir_t *dir, const char *name, long length,
+		    qid_t qid, unsigned int mode);
+void devlink(void);
+
+chan_t *devattach(int id, int dev);
+int devseek(chan_t *c, long off, int whence);
+chan_t *devclone(chan_t *c, chan_t *nc);
+int devgen(chan_t *c, const dirtab_t *tab, int ntab, int n, dir_t *dir);
+int devwalk(chan_t *c, const char *name, const dirtab_t *tab, int ntab,
+		   devgen_t *gen);
+int devstat(chan_t *dirc, const char *file, dir_t *dir,
+		   const dirtab_t *tab, int ntab, devgen_t *gen);
+
+chan_t *deverrmount(chan_t *c, const char *spec);
+int deverrwrite(chan_t *c, void *buf, int n);
+int deverrseek(chan_t *c, long off, int whence);
+
+extern dev_t *const devtab[];
+
+void __dead2 devpanic(const char *cause);
+
+#endif /* DEV_H */
diff --git a/lib/debugfs/devc.c b/lib/debugfs/devc.c
new file mode 100644
index 0000000..1099a85
--- /dev/null
+++ b/lib/debugfs/devc.c
@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2019, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+typedef struct dev dev_t;
+
+extern dev_t rootdevtab;
+extern dev_t fipdevtab;
+
+dev_t *const devtab[] = {
+	&rootdevtab,
+	&fipdevtab,
+	0
+};
+
+void devlink(void)
+{
+}
diff --git a/lib/debugfs/devfip.c b/lib/debugfs/devfip.c
new file mode 100644
index 0000000..85e6403
--- /dev/null
+++ b/lib/debugfs/devfip.c
@@ -0,0 +1,321 @@
+/*
+ * Copyright (c) 2019-2021, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <lib/debugfs.h>
+#include <limits.h>
+#include <plat/arm/common/plat_arm.h>
+#include <stdlib.h>
+#include <string.h>
+#include <tools_share/firmware_image_package.h>
+
+#include "dev.h"
+
+#define NR_FIPS		1
+#define STOC_HEADER	(sizeof(fip_toc_header_t))
+#define STOC_ENTRY	(sizeof(fip_toc_entry_t))
+
+struct fipfile {
+	chan_t	*c;
+	long	offset[NR_FILES];
+	long	size[NR_FILES];
+};
+
+struct fip_entry {
+	uuid_t		uuid;
+	long long	offset_address;
+	long long	size;
+	long long	flags;
+};
+
+struct uuidnames {
+	const char   name[NAMELEN];
+	const uuid_t uuid;
+};
+
+/*******************************************************************************
+ * This array links the FIP file names to their UUID.
+ * The elements are ordered according to the image number stored in
+ * tbbr_img_def.h, starting at index 1.
+ *
+ * TODO: this name to uuid binding will preferably be done using
+ * the coming Property Access Layer / Firmware CONFiguration feature.
+ ******************************************************************************/
+static const struct uuidnames uuidnames[] = {
+	{"",			{ {0}, {0}, {0}, 0, 0, {0} } },
+	{"bl2.bin",		UUID_TRUSTED_BOOT_FIRMWARE_BL2},
+	{"scp-bl2.bin",		UUID_SCP_FIRMWARE_SCP_BL2},
+	{"bl31.bin",		UUID_EL3_RUNTIME_FIRMWARE_BL31},
+	{"bl32.bin",		UUID_SECURE_PAYLOAD_BL32},
+	{"bl33.bin",		UUID_NON_TRUSTED_FIRMWARE_BL33},
+	{"tb-fw.crt",		UUID_TRUSTED_BOOT_FW_CERT},
+	{"trstd-k.crt",		UUID_TRUSTED_KEY_CERT},
+	{"scp-fw-k.crt",	UUID_SCP_FW_KEY_CERT},
+	{"soc-fw-k.crt",	UUID_SOC_FW_KEY_CERT},
+	{"tos-fw-k.crt",	UUID_TRUSTED_OS_FW_KEY_CERT},
+	{"nt-fw-k.crt",		UUID_NON_TRUSTED_FW_KEY_CERT},
+	{"scp-fw-c.crt",	UUID_SCP_FW_CONTENT_CERT},
+	{"soc-fw-c.crt",	UUID_SOC_FW_CONTENT_CERT},
+	{"tos-fw-c.crt",	UUID_TRUSTED_OS_FW_CONTENT_CERT},
+	{"nt-fw-c.crt",		UUID_NON_TRUSTED_FW_CONTENT_CERT},
+	{ },
+	{"fwu.crt",		UUID_TRUSTED_FWU_CERT},
+	{"scp-bl2u.bin",	UUID_TRUSTED_UPDATE_FIRMWARE_SCP_BL2U},
+	{"bl2u.bin",		UUID_TRUSTED_UPDATE_FIRMWARE_BL2U},
+	{"ns-bl2u.bin",		UUID_TRUSTED_UPDATE_FIRMWARE_NS_BL2U},
+	{"bl32-xtr1.bin",	UUID_SECURE_PAYLOAD_BL32_EXTRA1},
+	{"bl32-xtr2.bin",	UUID_SECURE_PAYLOAD_BL32_EXTRA2},
+	{"hw.cfg",		UUID_HW_CONFIG},
+	{"tb-fw.cfg",		UUID_TB_FW_CONFIG},
+	{"soc-fw.cfg",		UUID_SOC_FW_CONFIG},
+	{"tos-fw.cfg",		UUID_TOS_FW_CONFIG},
+	{"nt-fw.cfg",		UUID_NT_FW_CONFIG},
+	{"fw.cfg",		UUID_FW_CONFIG},
+	{"rot-k.crt",		UUID_ROT_KEY_CERT},
+	{"nt-k.crt",		UUID_NON_TRUSTED_WORLD_KEY_CERT},
+	{"sip-sp.crt",		UUID_SIP_SECURE_PARTITION_CONTENT_CERT},
+	{"plat-sp.crt",		UUID_PLAT_SECURE_PARTITION_CONTENT_CERT}
+};
+
+/*******************************************************************************
+ * This array contains all the available FIP files.
+ ******************************************************************************/
+static struct fipfile archives[NR_FIPS];
+
+/*******************************************************************************
+ * This variable stores the current number of registered FIP files.
+ ******************************************************************************/
+static int nfips;
+
+/*******************************************************************************
+ * This function parses the ToC of the FIP.
+ ******************************************************************************/
+static int get_entry(chan_t *c, struct fip_entry *entry)
+{
+	int n;
+
+	n = devtab[c->index]->read(c, entry, sizeof(struct fip_entry));
+	if (n <= 0) {
+		return n;
+	}
+
+	if (n != sizeof(struct fip_entry)) {
+		return -1;
+	}
+
+	if (entry->size == 0) {
+		return 0;
+	}
+
+	return 1;
+}
+
+/*******************************************************************************
+ * This function exposes the FIP images as files.
+ ******************************************************************************/
+static int fipgen(chan_t *c, const dirtab_t *tab, int ntab, int n, dir_t *dir)
+{
+	int i, r;
+	long off;
+	chan_t nc;
+	struct fip_entry entry;
+	struct fipfile *fip;
+	static const char unk[] = "unknown";
+
+	if (c->dev >= nfips) {
+		panic();
+	}
+
+	if (clone(archives[c->dev].c, &nc) == NULL) {
+		panic();
+	}
+
+	fip = &archives[nc.dev];
+
+	off = STOC_HEADER;
+	for (i = 0; i <= n; i++) {
+		if (fip->offset[i] == -1) {
+			return 0;
+		}
+
+		if (devtab[nc.index]->seek(&nc, off, KSEEK_SET) < 0) {
+			return -1;
+		}
+
+		r = get_entry(&nc, &entry);
+		if (r <= 0) {
+			return r;
+		}
+
+		off += sizeof(entry);
+	}
+
+	for (i = 1; i < NELEM(uuidnames); i++) {
+		if (memcmp(&uuidnames[i].uuid,
+			   &entry.uuid, sizeof(uuid_t)) == 0) {
+			break;
+		}
+	}
+
+	if (i < NELEM(uuidnames)) {
+		make_dir_entry(c, dir, uuidnames[i].name,
+			       entry.size, n, O_READ);
+	} else {
+		// TODO: set name depending on uuid node value
+		make_dir_entry(c, dir, unk, entry.size, n, O_READ);
+	}
+
+	return 1;
+}
+
+static int fipwalk(chan_t *c, const char *name)
+{
+	return devwalk(c, name, NULL, 0, fipgen);
+}
+
+static int fipstat(chan_t *c, const char *file, dir_t *dir)
+{
+	return devstat(c, file, dir, NULL, 0, fipgen);
+}
+
+/*******************************************************************************
+ * This function copies at most n bytes of the FIP image referred by c into
+ * buf.
+ ******************************************************************************/
+static int fipread(chan_t *c, void *buf, int n)
+{
+	long off;
+	chan_t cs;
+	struct fipfile *fip;
+	long size;
+
+	/* Only makes sense when using debug language */
+	assert(c->qid != CHDIR);
+
+	if ((c->dev >= nfips) || ((c->qid & CHDIR) != 0)) {
+		panic();
+	}
+
+	fip = &archives[c->dev];
+
+	if ((c->qid >= NR_FILES) || (fip->offset[c->qid] < 0)) {
+		panic();
+	}
+
+	if (clone(fip->c, &cs) == NULL) {
+		panic();
+	}
+
+	size = fip->size[c->qid];
+	if (c->offset >= size) {
+		return 0;
+	}
+
+	if (n < 0) {
+		return -1;
+	}
+
+	if (n > (size - c->offset)) {
+		n = size - c->offset;
+	}
+
+	off = fip->offset[c->qid] + c->offset;
+	if (devtab[cs.index]->seek(&cs, off, KSEEK_SET) < 0) {
+		return -1;
+	}
+
+	n = devtab[cs.index]->read(&cs, buf, n);
+	if (n > 0) {
+		c->offset += n;
+	}
+
+	return n;
+}
+
+/*******************************************************************************
+ * This function parses the FIP spec and registers its images in order to
+ * expose them as files in the driver namespace.
+ * It acts as an initialization function for the FIP driver.
+ * It returns a pointer to the newly created channel.
+ ******************************************************************************/
+static chan_t *fipmount(chan_t *c, const char *spec)
+{
+	int r, n, t;
+	chan_t *cspec;
+	uint32_t hname;
+	struct fip_entry entry;
+	struct fipfile *fip;
+	dir_t dir;
+
+	if (nfips == NR_FIPS) {
+		return NULL;
+	}
+
+	fip = &archives[nfips];
+
+	for (n = 0; n < NR_FILES; n++) {
+		fip->offset[n] = -1;
+	}
+
+	cspec = path_to_channel(spec, O_READ);
+	if (cspec == NULL) {
+		return NULL;
+	}
+
+	fip->c = cspec;
+
+	r = devtab[cspec->index]->read(cspec, &hname, sizeof(hname));
+	if (r < 0) {
+		goto err;
+	}
+
+	if ((r != sizeof(hname)) || (hname != TOC_HEADER_NAME)) {
+		goto err;
+	}
+
+	if (stat(spec, &dir) < 0) {
+		goto err;
+	}
+
+	t = cspec->index;
+	if (devtab[t]->seek(cspec, STOC_HEADER, KSEEK_SET) < 0) {
+		goto err;
+	}
+
+	for (n = 0; n < NR_FILES; n++) {
+		switch (get_entry(cspec, &entry)) {
+		case 0:
+			return attach('F', nfips++);
+		case -1:
+			goto err;
+		default:
+			if ((entry.offset_address + entry.size) > dir.length) {
+				goto err;
+			}
+
+			fip->offset[n] = entry.offset_address;
+			fip->size[n] = entry.size;
+			break;
+		}
+	}
+
+err:
+	channel_close(cspec);
+	return NULL;
+}
+
+const dev_t fipdevtab = {
+	.id = 'F',
+	.stat = fipstat,
+	.clone = devclone,
+	.attach = devattach,
+	.walk = fipwalk,
+	.read = fipread,
+	.write = deverrwrite,
+	.mount = fipmount,
+	.seek = devseek
+};
+
diff --git a/lib/debugfs/devroot.c b/lib/debugfs/devroot.c
new file mode 100644
index 0000000..9dd6c92
--- /dev/null
+++ b/lib/debugfs/devroot.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2019, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <common/debug.h>
+#include <lib/debugfs.h>
+
+#include "blobs.h"
+#include "dev.h"
+
+/*******************************************************************************
+ * This array contains the directories available from the root directory.
+ ******************************************************************************/
+static const dirtab_t dirtab[] = {
+	{"dev",   CHDIR | DEV_ROOT_QDEV,   0, O_READ},
+	{"blobs", CHDIR | DEV_ROOT_QBLOBS, 0, O_READ},
+	{"fip",   CHDIR | DEV_ROOT_QFIP,   0, O_READ}
+};
+
+static const dirtab_t devfstab[] = {
+};
+
+/*******************************************************************************
+ * This function exposes the elements of the root directory.
+ * It also exposes the content of the dev and blobs directories.
+ ******************************************************************************/
+static int rootgen(chan_t *channel, const dirtab_t *tab, int ntab,
+		   int n, dir_t *dir)
+{
+	switch (channel->qid & ~CHDIR) {
+	case DEV_ROOT_QROOT:
+		tab = dirtab;
+		ntab = NELEM(dirtab);
+		break;
+	case DEV_ROOT_QDEV:
+		tab = devfstab;
+		ntab = NELEM(devfstab);
+		break;
+	case DEV_ROOT_QBLOBS:
+		tab = blobtab;
+		ntab = NELEM(blobtab);
+		break;
+	default:
+		return 0;
+	}
+
+	return devgen(channel, tab, ntab, n, dir);
+}
+
+static int rootwalk(chan_t *channel, const char *name)
+{
+	return devwalk(channel, name, NULL, 0, rootgen);
+}
+
+/*******************************************************************************
+ * This function copies at most n bytes from the element referred by c into buf.
+ ******************************************************************************/
+static int rootread(chan_t *channel, void *buf, int size)
+{
+	const dirtab_t *dp;
+	dir_t *dir;
+
+	if ((channel->qid & CHDIR) != 0) {
+		if (size < sizeof(dir_t)) {
+			return -1;
+		}
+
+		dir = buf;
+		return dirread(channel, dir, NULL, 0, rootgen);
+	}
+
+	/* Only makes sense when using debug language */
+	assert(channel->qid != DEV_ROOT_QBLOBCTL);
+
+	dp = &blobtab[channel->qid - DEV_ROOT_QBLOBCTL];
+	return buf_to_channel(channel, buf, dp->data, size, dp->length);
+}
+
+static int rootstat(chan_t *channel, const char *file, dir_t *dir)
+{
+	return devstat(channel, file, dir, NULL, 0, rootgen);
+}
+
+const dev_t rootdevtab = {
+	.id = '/',
+	.stat = rootstat,
+	.clone = devclone,
+	.attach = devattach,
+	.walk = rootwalk,
+	.read = rootread,
+	.write = deverrwrite,
+	.mount = deverrmount,
+	.seek = devseek
+};