sandbox: tpm: Split out common nvdata code

We want to support nvdata in TPM2 as well. To avoid code duplicating the
associated code, move it into a common file.

Drop the special-case logic for the kernel space. This can be handled by
the higher-level code now, i.e. in vboot itself.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 96 insertions, 0 deletions

diff --git a/drivers/tpm/sandbox_common.h b/drivers/tpm/sandbox_common.h
new file mode 100644
index 00000000000..aa5292d7945
--- /dev/null
+++ b/drivers/tpm/sandbox_common.h
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Common features for sandbox TPM1 and TPM2 implementations
+ *
+ * Copyright 2021 Google LLC
+ */
+
+#ifndef __TPM_SANDBOX_COMMON_H
+#define __TPM_SANDBOX_COMMON_H
+
+/*
+ * These numbers derive from adding the sizes of command fields as shown in
+ * the TPM commands manual.
+ */
+#define TPM_HDR_LEN	10
+
+/* These are the different non-volatile spaces that we emulate */
+enum sandbox_nv_space {
+	NV_SEQ_ENABLE_LOCKING,
+	NV_SEQ_GLOBAL_LOCK,
+	NV_SEQ_FIRMWARE,
+	NV_SEQ_KERNEL,
+	NV_SEQ_BACKUP,
+	NV_SEQ_FWMP,
+	NV_SEQ_REC_HASH,
+
+	NV_SEQ_COUNT,
+};
+
+/* TPM NVRAM location indices */
+#define FIRMWARE_NV_INDEX		0x1007
+#define KERNEL_NV_INDEX			0x1008
+#define BACKUP_NV_INDEX			0x1009
+#define FWMP_NV_INDEX			0x100a
+#define MRC_REC_HASH_NV_INDEX		0x100b
+
+/* Size of each non-volatile space */
+#define NV_DATA_SIZE		0x28
+
+/**
+ * struct nvdata_state - state of a single non-volatile-data 'space'
+ *
+ * @present: true if present
+ * @length: length in bytes (max NV_DATA_SIZE)
+ * @data: contents of non-volatile space
+ */
+struct nvdata_state {
+	bool present;
+	int length;
+	u8 data[NV_DATA_SIZE];
+};
+
+/**
+ * sb_tpm_index_to_seq() - convert an index into a space sequence number
+ *
+ * This converts the index as used by the vboot code into an internal sequence
+ * number used by the sandbox emulation.
+ *
+ * @index: Index to use (FIRMWARE_NV_INDEX, etc.)
+ * @return associated space (enum sandbox_nv_space)
+ */
+int sb_tpm_index_to_seq(uint index);
+
+/**
+ * sb_tpm_read_data() - Read non-volatile data
+ *
+ * This handles a TPM read of nvdata. If the nvdata is not present, a
+ * TPM_BADINDEX error is put in the buffer. If @length is too large,
+ * TPM_BAD_DATASIZE is put in the buffer.
+ *
+ * @nvdata: Current nvdata state
+ * @seq: Sequence number to read
+ * @recvbuf: Buffer to update with the TPM response, assumed to contain zeroes
+ * @data_ofs: Offset of the 'data' portion of @recvbuf
+ * @length: Number of bytes to read
+ */
+void sb_tpm_read_data(const struct nvdata_state nvdata[NV_SEQ_COUNT],
+		      enum sandbox_nv_space seq, u8 *recvbuf, int data_ofs,
+		      int length);
+
+/**
+ * sb_tpm_write_data() - Write non-volatile data
+ *
+ * If @length is too large, an error is logged and nothing is written.
+ *
+ * @nvdata: Current nvdata state
+ * @seq: Sequence number to read
+ * @buf: Buffer containing the data to write
+ * @data_ofs: Offset of the 'data' portion of @buf
+ * @length: Number of bytes to write
+ */
+void sb_tpm_write_data(struct nvdata_state nvdata[NV_SEQ_COUNT],
+		       enum sandbox_nv_space seq, const u8 *buf, int data_ofs,
+		       int length);
+
+#endif