[PATCHv4 2/5] fwu: move meta-data management in core

[jassisinghbrar@gmail.com]

From: Jassi Brar <jaswinder.singh@linaro.org>

Instead of each i/f having to implement their own meta-data verification
and storage, move the logic in common code. This simplifies the i/f code
much simpler and compact.

Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
---
 drivers/fwu-mdata/fwu-mdata-uclass.c |  34 +++++++
 include/fwu.h                        |  41 ++++++++
 lib/fwu_updates/fwu.c                | 135 ++++++++++++++++++++++++++-
 3 files changed, 206 insertions(+), 4 deletions(-)

diff --git a/drivers/fwu-mdata/fwu-mdata-uclass.c b/drivers/fwu-mdata/fwu-mdata-uclass.c
index b477e9603f..e03773c584 100644
--- a/drivers/fwu-mdata/fwu-mdata-uclass.c
+++ b/drivers/fwu-mdata/fwu-mdata-uclass.c
@@ -16,6 +16,40 @@
 #include <linux/types.h>
 #include <u-boot/crc.h>
 
+/**
+ * fwu_read_mdata() - Wrapper around fwu_mdata_ops.read_mdata()
+ *
+ * Return: 0 if OK, -ve on error
+ */
+int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
+{
+	const struct fwu_mdata_ops *ops = device_get_ops(dev);
+
+	if (!ops->read_mdata) {
+		log_debug("read_mdata() method not defined\n");
+		return -ENOSYS;
+	}
+
+	return ops->read_mdata(dev, mdata, primary);
+}
+
+/**
+ * fwu_write_mdata() - Wrapper around fwu_mdata_ops.write_mdata()
+ *
+ * Return: 0 if OK, -ve on error
+ */
+int fwu_write_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
+{
+	const struct fwu_mdata_ops *ops = device_get_ops(dev);
+
+	if (!ops->write_mdata) {
+		log_debug("write_mdata() method not defined\n");
+		return -ENOSYS;
+	}
+
+	return ops->write_mdata(dev, mdata, primary);
+}
+
 /**
  * fwu_get_mdata_part_num() - Get the FWU metadata partition numbers
  * @dev: FWU metadata device
diff --git a/include/fwu.h b/include/fwu.h
index 0919ced812..1a700c9e6a 100644
--- a/include/fwu.h
+++ b/include/fwu.h
@@ -24,6 +24,26 @@ struct fwu_mdata_gpt_blk_priv {
  * @update_mdata() - Update the FWU metadata copy
  */
 struct fwu_mdata_ops {
+	/**
+	 * read_mdata() - Populate the asked FWU metadata copy
+	 * @dev: FWU metadata device
+	 * @mdata: Copy of the FWU metadata
+	 * @primary: If primary or secondary copy of meta-data is to be read
+	 *
+	 * Return: 0 if OK, -ve on error
+	 */
+	int (*read_mdata)(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
+
+	/**
+	 * write_mdata() - Write the given FWU metadata copy
+	 * @dev: FWU metadata device
+	 * @mdata: Copy of the FWU metadata
+	 * @primary: If primary or secondary copy of meta-data is to be written
+	 *
+	 * Return: 0 if OK, -ve on error
+	 */
+	int (*write_mdata)(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
+
 	/**
 	 * check_mdata() - Check if the FWU metadata is valid
 	 * @dev:	FWU device
@@ -126,6 +146,27 @@ struct fwu_mdata_ops {
 	EFI_GUID(0x0c996046, 0xbcc0, 0x4d04, 0x85, 0xec, \
 		 0xe1, 0xfc, 0xed, 0xf1, 0xc6, 0xf8)
 
+/**
+ * fwu_read_mdata() - Wrapper around fwu_mdata_ops.read_mdata()
+ */
+int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
+
+/**
+ * fwu_write_mdata() - Wrapper around fwu_mdata_ops.write_mdata()
+ */
+int fwu_write_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
+
+/**
+ * fwu_get_verified_mdata() - Read, verify and return the FWU metadata
+ *
+ * Read both the metadata copies from the storage media, verify their checksum,
+ * and ascertain that both copies match. If one of the copies has gone bad,
+ * restore it from the good copy.
+ *
+ * Return: 0 if OK, -ve on error
+*/
+int fwu_get_verified_mdata(struct fwu_mdata *mdata);
+
 /**
  * fwu_check_mdata_validity() - Check for validity of the FWU metadata copies
  *
diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
index 5313d07302..56299f1b2f 100644
--- a/lib/fwu_updates/fwu.c
+++ b/lib/fwu_updates/fwu.c
@@ -15,13 +15,13 @@
 #include <linux/errno.h>
 #include <linux/types.h>
 
+#include <u-boot/crc.h>
+
+static struct fwu_mdata g_mdata; /* = {0} makes uninit crc32 always invalid */
+static struct udevice *g_dev;
 static u8 in_trial;
 static u8 boottime_check;
 
-#include <linux/errno.h>
-#include <linux/types.h>
-#include <u-boot/crc.h>
-
 enum {
 	IMAGE_ACCEPT_SET = 1,
 	IMAGE_ACCEPT_CLEAR,
@@ -161,6 +161,133 @@ static int fwu_get_image_type_id(u8 *image_index, efi_guid_t *image_type_id)
 	return -ENOENT;
 }
 
+/**
+ * fwu_sync_mdata() - Update given meta-data partition(s) with the copy provided
+ * @mdata: FWU metadata structure
+ * @part: Bitmask of FWU metadata partitions to be written to
+ *
+ * Return: 0 if OK, -ve on error
+ */
+static int fwu_sync_mdata(struct fwu_mdata *mdata, int part)
+{
+	void *buf = &mdata->version;
+	int err = 0;
+
+	/*
+	 * Calculate the crc32 for the updated FWU metadata
+	 * and put the updated value in the FWU metadata crc32
+	 * field
+	 */
+	mdata->crc32 = crc32(0, buf, sizeof(*mdata) - sizeof(u32));
+
+	err = fwu_write_mdata(g_dev, mdata, part & PRIMARY_PART ? true : false);
+	if (err) {
+		log_err("Unable to write %s mdata\n",
+				part & PRIMARY_PART ?  "primary": "secondary");
+		return err;
+	}
+
+	/* update the cached copy of meta-data */
+	memcpy(&g_mdata, mdata, sizeof(struct fwu_mdata));
+
+	return 0;
+}
+
+static inline int mdata_crc_check(struct fwu_mdata *mdata)
+{
+	void *buf = &mdata->version;
+	u32 calc_crc32 = crc32(0, buf, sizeof(*mdata) - sizeof(u32));
+
+	return calc_crc32 == mdata->crc32 ? 0 : -EINVAL;
+}
+
+/**
+ * fwu_get_verified_mdata() - Read, verify and return the FWU metadata
+ *
+ * Read both the metadata copies from the storage media, verify their checksum,
+ * and ascertain that both copies match. If one of the copies has gone bad,
+ * restore it from the good copy.
+ *
+ * Return: 0 if OK, -ve on error
+ */
+int fwu_get_verified_mdata(struct fwu_mdata *mdata)
+{
+	int err;
+	bool pri_ok, sec_ok;
+	struct fwu_mdata s, *p_mdata, *s_mdata;
+
+	p_mdata = &g_mdata;
+	s_mdata = &s;
+
+	/* if mdata already read and ready */
+	err = mdata_crc_check(p_mdata);
+	if (!err)
+		goto ret_mdata;
+	/* else read, verify and, if needed, fix mdata */
+
+	pri_ok = false;
+	err = fwu_read_mdata(g_dev, p_mdata, true);
+	if (!err) {
+		err = mdata_crc_check(p_mdata);
+		if (!err)
+			pri_ok = true;
+		else
+			log_debug("primary mdata: crc32 failed\n");
+	}
+
+	sec_ok = false;
+	err = fwu_read_mdata(g_dev, s_mdata, false);
+	if (!err) {
+		err = mdata_crc_check(s_mdata);
+		if (!err)
+			sec_ok = true;
+		else
+			log_debug("secondary mdata: crc32 failed\n");
+	}
+
+	if (pri_ok && sec_ok) {
+		/*
+		 * Before returning, check that both the
+		 * FWU metadata copies are the same.
+		 */
+		err = memcmp(p_mdata, s_mdata, sizeof(struct fwu_mdata));
+		if (!err)
+			goto ret_mdata;
+
+		/*
+		 * If not, populate the secondary partition from the
+		 * primary partition copy.
+		 */
+		log_info("Both FWU metadata copies are valid but do not match.");
+		log_info(" Restoring the secondary partition from the primary\n");
+		sec_ok = false;
+	}
+
+	if (!pri_ok) {
+		memcpy(p_mdata, s_mdata, sizeof(struct fwu_mdata));
+		err = fwu_sync_mdata(p_mdata, PRIMARY_PART);
+		if (err) {
+			log_debug("mdata : primary write failed\n");
+			return err;
+		}
+	}
+
+	if (!sec_ok) {
+		memcpy(s_mdata, p_mdata, sizeof(struct fwu_mdata));
+		err = fwu_sync_mdata(s_mdata, SECONDARY_PART);
+		if (err) {
+			log_debug("mdata : secondary write failed\n");
+			return err;
+		}
+	}
+
+ret_mdata:
+	if (!err && mdata)
+		memcpy(mdata, p_mdata, sizeof(struct fwu_mdata));
+
+	return err;
+}
+
 /**
  * fwu_verify_mdata() - Verify the FWU metadata
  * @mdata: FWU metadata structure
-- 
2.34.1