debugfs: add 9p device interface
The 9p interface provides abstraction layers allowing the software
that uses devices to be independent from the hardware.
This patch provides a file system abstraction to link drivers to their
devices and propose a common interface to expose driver operations to
higher layers. This file system can be used to access and configure a
device by doing read/write operations.
Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: Ia9662393baf489855dc0c8f389fe4a0afbc9c255
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
+};