1 files changed, 74 insertions, 0 deletions
diff --git a/include/linux/ihex.h b/include/linux/ihex.h
new file mode 100644
index 00000000000..2baace2788a
--- /dev/null
+++ b/include/linux/ihex.h
@@ -0,0 +1,74 @@
+/*
+ * Compact binary representation of ihex records. Some devices need their
+ * firmware loaded in strange orders rather than a single big blob, but
+ * actually parsing ihex-as-text within the kernel seems silly. Thus,...
+ */
+
+#ifndef __LINUX_IHEX_H__
+#define __LINUX_IHEX_H__
+
+#include <linux/types.h>
+#include <linux/firmware.h>
+#include <linux/device.h>
+
+/* Intel HEX files actually limit the length to 256 bytes, but we have
+   drivers which would benefit from using separate records which are
+   longer than that, so we extend to 16 bits of length */
+struct ihex_binrec {
+	__be32 addr;
+	__be16 len;
+	uint8_t data[0];
+} __attribute__((aligned(4)));
+
+/* Find the next record, taking into account the 4-byte alignment */
+static inline const struct ihex_binrec *
+ihex_next_binrec(const struct ihex_binrec *rec)
+{
+	int next = ((be16_to_cpu(rec->len) + 5) & ~3) - 2;
+	rec = (void *)&rec->data[next];
+
+	return be16_to_cpu(rec->len) ? rec : NULL;
+}
+
+/* Check that ihex_next_binrec() won't take us off the end of the image... */
+static inline int ihex_validate_fw(const struct firmware *fw)
+{
+	const struct ihex_binrec *rec;
+	size_t ofs = 0;
+
+	while (ofs <= fw->size - sizeof(*rec)) {
+		rec = (void *)&fw->data[ofs];
+
+		/* Zero length marks end of records */
+		if (!be16_to_cpu(rec->len))
+			return 0;
+
+		/* Point to next record... */
+		ofs += (sizeof(*rec) + be16_to_cpu(rec->len) + 3) & ~3;
+	}
+	return -EINVAL;
+}
+
+/* Request firmware and validate it so that we can trust we won't
+ * run off the end while reading records... */
+static inline int request_ihex_firmware(const struct firmware **fw,
+					const char *fw_name,
+					struct device *dev)
+{
+	const struct firmware *lfw;
+	int ret;
+
+	ret = request_firmware(&lfw, fw_name, dev);
+	if (ret)
+		return ret;
+	ret = ihex_validate_fw(lfw);
+	if (ret) {
+		dev_err(dev, "Firmware \"%s\" not valid IHEX records\n",
+			fw_name);
+		release_firmware(lfw);
+		return ret;
+	}
+	*fw = lfw;
+	return 0;
+}
+#endif /* __LINUX_IHEX_H__ */