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-rw-r--r--common/state/backend.c188
1 files changed, 188 insertions, 0 deletions
diff --git a/common/state/backend.c b/common/state/backend.c
new file mode 100644
index 0000000..2f2e6df
--- /dev/null
+++ b/common/state/backend.c
@@ -0,0 +1,188 @@
+/*
+ * Copyright (C) 2016 Pengutronix, Markus Pargmann <mpa@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/string.h>
+#include <malloc.h>
+#include <printk.h>
+
+#include "state.h"
+
+
+/**
+ * Save the state
+ * @param state
+ * @return
+ */
+int state_save(struct state *state)
+{
+ uint8_t *buf;
+ ssize_t len;
+ int ret;
+ struct state_backend *backend = &state->backend;
+
+ if (!state->dirty)
+ return 0;
+
+ ret = backend->format->pack(backend->format, state, &buf, &len);
+ if (ret) {
+ dev_err(&state->dev, "Failed to pack state with backend format %s, %d\n",
+ backend->format->name, ret);
+ return ret;
+ }
+
+ ret = state_storage_write(&backend->storage, buf, len);
+ if (ret) {
+ dev_err(&state->dev, "Failed to write packed state, %d\n", ret);
+ goto out;
+ }
+
+ state->dirty = 0;
+
+out:
+ free(buf);
+ return ret;
+}
+
+/**
+ * state_load - Loads a state from the backend
+ * @param state The state that should be updated to contain the loaded data
+ * @return 0 on success, -errno on failure. If no state is loaded the previous
+ * values remain in the state.
+ *
+ * This function uses the registered storage backend to read data. All data that
+ * we read is checked for integrity by the formatter. After that we unpack the
+ * data into our state.
+ */
+int state_load(struct state *state)
+{
+ uint8_t *buf;
+ ssize_t len;
+ ssize_t len_hint = 0;
+ int ret;
+ struct state_backend *backend = &state->backend;
+
+ if (backend->format->get_packed_len)
+ len_hint = backend->format->get_packed_len(backend->format,
+ state);
+ ret = state_storage_read(&backend->storage, backend->format,
+ state->magic, &buf, &len, len_hint);
+ if (ret) {
+ dev_err(&state->dev, "Failed to read state with format %s, %d\n",
+ backend->format->name, ret);
+ return ret;
+ }
+
+ ret = backend->format->unpack(backend->format, state, buf, len);
+ if (ret) {
+ dev_err(&state->dev, "Failed to unpack read data with format %s although verified, %d\n",
+ backend->format->name, ret);
+ goto out;
+ }
+
+ state->dirty = 0;
+
+out:
+ free(buf);
+ return ret;
+}
+
+static int state_format_init(struct state_backend *backend,
+ struct device_d *dev, const char *backend_format,
+ struct device_node *node, const char *state_name)
+{
+ int ret;
+
+ if (!strcmp(backend_format, "raw")) {
+ ret = backend_format_raw_create(&backend->format, node,
+ state_name, dev);
+ } else if (!strcmp(backend_format, "dtb")) {
+ ret = backend_format_dtb_create(&backend->format, dev);
+ } else {
+ dev_err(dev, "Invalid backend format %s\n",
+ backend_format);
+ return -EINVAL;
+ }
+
+ if (ret && ret != -EPROBE_DEFER)
+ dev_err(dev, "Failed to initialize format %s, %d\n",
+ backend_format, ret);
+
+ return ret;
+}
+
+static void state_format_free(struct state_backend_format *format)
+{
+ if (format->free)
+ format->free(format);
+}
+
+/**
+ * state_backend_init - Initiates the backend storage and format using the
+ * passed arguments
+ * @param backend state backend
+ * @param dev Device pointer used for prints
+ * @param node the DT device node corresponding to the state
+ * @param backend_format a string describing the format. Valid values are 'raw'
+ * and 'dtb' currently
+ * @param storage_path Path to the backend storage file/device/partition/...
+ * @param state_name Name of the state
+ * @param of_path Path in the devicetree
+ * @param stridesize stridesize in case we have a medium without eraseblocks.
+ * stridesize describes how far apart copies of the same data should be stored.
+ * For blockdevices it makes sense to align them on blocksize.
+ * @param storagetype Type of the storage backend. This may be NULL where we
+ * autoselect some backwardscompatible backend options
+ * @return 0 on success, -errno otherwise
+ */
+int state_backend_init(struct state_backend *backend, struct device_d *dev,
+ struct device_node *node, const char *backend_format,
+ const char *storage_path, const char *state_name, const
+ char *of_path, off_t offset, size_t max_size,
+ uint32_t stridesize, const char *storagetype)
+{
+ int ret;
+
+ ret = state_format_init(backend, dev, backend_format, node, state_name);
+ if (ret)
+ return ret;
+
+ ret = state_storage_init(&backend->storage, dev, storage_path, offset,
+ max_size, stridesize, storagetype);
+ if (ret)
+ goto out_free_format;
+
+ backend->of_path = of_path;
+
+ return 0;
+
+out_free_format:
+ state_format_free(backend->format);
+ backend->format = NULL;
+
+ return ret;
+}
+
+void state_backend_set_readonly(struct state_backend *backend)
+{
+ state_storage_set_readonly(&backend->storage);
+}
+
+void state_backend_free(struct state_backend *backend)
+{
+ state_storage_free(&backend->storage);
+ if (backend->format)
+ state_format_free(backend->format);
+}