366 lines
		
	
	
		
			9.1 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			366 lines
		
	
	
		
			9.1 KiB
		
	
	
	
		
			C
		
	
	
	
// SPDX-License-Identifier: GPL-2.0+
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/*
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 * Copyright (c) 2013 Google, Inc
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 */
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#include <common.h>
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#include <dm.h>
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#include <tpm-v1.h>
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#include <asm/state.h>
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#include <asm/unaligned.h>
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#include <linux/crc8.h>
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/* TPM NVRAM location indices. */
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#define FIRMWARE_NV_INDEX		0x1007
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#define KERNEL_NV_INDEX			0x1008
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#define BACKUP_NV_INDEX                 0x1009
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#define FWMP_NV_INDEX                   0x100a
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#define REC_HASH_NV_INDEX               0x100b
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#define REC_HASH_NV_SIZE                VB2_SHA256_DIGEST_SIZE
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#define NV_DATA_PUBLIC_PERMISSIONS_OFFSET	60
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/* Kernel TPM space - KERNEL_NV_INDEX, locked with physical presence */
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#define ROLLBACK_SPACE_KERNEL_VERSION	2
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#define ROLLBACK_SPACE_KERNEL_UID	0x4752574C  /* 'GRWL' */
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struct rollback_space_kernel {
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	/* Struct version, for backwards compatibility */
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	uint8_t struct_version;
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	/* Unique ID to detect space redefinition */
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	uint32_t uid;
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	/* Kernel versions */
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	uint32_t kernel_versions;
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	/* Reserved for future expansion */
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	uint8_t reserved[3];
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	/* Checksum (v2 and later only) */
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	uint8_t crc8;
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} __packed rollback_space_kernel;
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/*
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 * These numbers derive from adding the sizes of command fields as shown in
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 * the TPM commands manual.
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 */
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#define TPM_REQUEST_HEADER_LENGTH	10
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#define TPM_RESPONSE_HEADER_LENGTH	10
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/* These are the different non-volatile spaces that we emulate */
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enum {
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	NV_GLOBAL_LOCK,
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	NV_SEQ_FIRMWARE,
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	NV_SEQ_KERNEL,
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	NV_SEQ_BACKUP,
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	NV_SEQ_FWMP,
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	NV_SEQ_REC_HASH,
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	NV_SEQ_COUNT,
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};
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/* Size of each non-volatile space */
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#define NV_DATA_SIZE		0x20
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struct nvdata_state {
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	bool present;
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	u8 data[NV_DATA_SIZE];
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};
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/*
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 * Information about our TPM emulation. This is preserved in the sandbox
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 * state file if enabled.
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 */
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static struct tpm_state {
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	bool valid;
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	struct nvdata_state nvdata[NV_SEQ_COUNT];
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} g_state;
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/**
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 * sandbox_tpm_read_state() - read the sandbox EC state from the state file
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 *
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 * If data is available, then blob and node will provide access to it. If
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 * not this function sets up an empty TPM.
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 *
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 * @blob: Pointer to device tree blob, or NULL if no data to read
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 * @node: Node offset to read from
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 */
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static int sandbox_tpm_read_state(const void *blob, int node)
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{
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	const char *prop;
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	int len;
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	int i;
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	if (!blob)
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		return 0;
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	for (i = 0; i < NV_SEQ_COUNT; i++) {
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		char prop_name[20];
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		sprintf(prop_name, "nvdata%d", i);
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		prop = fdt_getprop(blob, node, prop_name, &len);
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		if (prop && len == NV_DATA_SIZE) {
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			memcpy(g_state.nvdata[i].data, prop, NV_DATA_SIZE);
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			g_state.nvdata[i].present = true;
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		}
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	}
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	g_state.valid = true;
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	return 0;
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}
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/**
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 * cros_ec_write_state() - Write out our state to the state file
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 *
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 * The caller will ensure that there is a node ready for the state. The node
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 * may already contain the old state, in which case it is overridden.
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 *
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 * @blob: Device tree blob holding state
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 * @node: Node to write our state into
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 */
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static int sandbox_tpm_write_state(void *blob, int node)
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{
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	int i;
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	/*
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	 * We are guaranteed enough space to write basic properties.
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	 * We could use fdt_add_subnode() to put each set of data in its
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	 * own node - perhaps useful if we add access informaiton to each.
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	 */
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	for (i = 0; i < NV_SEQ_COUNT; i++) {
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		char prop_name[20];
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		if (g_state.nvdata[i].present) {
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			sprintf(prop_name, "nvdata%d", i);
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			fdt_setprop(blob, node, prop_name,
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				    g_state.nvdata[i].data, NV_DATA_SIZE);
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		}
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	}
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	return 0;
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}
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SANDBOX_STATE_IO(sandbox_tpm, "google,sandbox-tpm", sandbox_tpm_read_state,
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		 sandbox_tpm_write_state);
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static int index_to_seq(uint32_t index)
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{
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	switch (index) {
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	case FIRMWARE_NV_INDEX:
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		return NV_SEQ_FIRMWARE;
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	case KERNEL_NV_INDEX:
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		return NV_SEQ_KERNEL;
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	case BACKUP_NV_INDEX:
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		return NV_SEQ_BACKUP;
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	case FWMP_NV_INDEX:
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		return NV_SEQ_FWMP;
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	case REC_HASH_NV_INDEX:
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		return NV_SEQ_REC_HASH;
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	case 0:
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		return NV_GLOBAL_LOCK;
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	}
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	printf("Invalid nv index %#x\n", index);
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	return -1;
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}
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static void handle_cap_flag_space(u8 **datap, uint index)
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{
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	struct tpm_nv_data_public pub;
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	/* TPM_NV_PER_PPWRITE */
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	memset(&pub, '\0', sizeof(pub));
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	pub.nv_index = __cpu_to_be32(index);
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	pub.pcr_info_read.pcr_selection.size_of_select = __cpu_to_be16(
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		sizeof(pub.pcr_info_read.pcr_selection.pcr_select));
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	pub.permission.attributes = __cpu_to_be32(1);
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	pub.pcr_info_write = pub.pcr_info_read;
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	memcpy(*datap, &pub, sizeof(pub));
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	*datap += sizeof(pub);
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}
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static int sandbox_tpm_xfer(struct udevice *dev, const uint8_t *sendbuf,
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			    size_t send_size, uint8_t *recvbuf,
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			    size_t *recv_len)
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{
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	struct tpm_state *tpm = dev_get_priv(dev);
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	uint32_t code, index, length, type;
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	uint8_t *data;
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	int seq;
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	code = get_unaligned_be32(sendbuf + sizeof(uint16_t) +
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				  sizeof(uint32_t));
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#ifdef DEBUG
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	printf("tpm: %zd bytes, recv_len %zd, cmd = %x\n", send_size,
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	       *recv_len, code);
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	print_buffer(0, sendbuf, 1, send_size, 0);
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#endif
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	switch (code) {
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	case TPM_CMD_GET_CAPABILITY:
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		type = get_unaligned_be32(sendbuf + 14);
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		switch (type) {
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		case TPM_CAP_FLAG:
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			index = get_unaligned_be32(sendbuf + 18);
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			printf("Get flags index %#02x\n", index);
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			*recv_len = 22;
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			memset(recvbuf, '\0', *recv_len);
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			data = recvbuf + TPM_RESPONSE_HEADER_LENGTH +
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					sizeof(uint32_t);
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			switch (index) {
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			case FIRMWARE_NV_INDEX:
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				break;
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			case KERNEL_NV_INDEX:
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				handle_cap_flag_space(&data, index);
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				*recv_len = data - recvbuf -
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					TPM_RESPONSE_HEADER_LENGTH -
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					sizeof(uint32_t);
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				break;
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			case TPM_CAP_FLAG_PERMANENT: {
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				struct tpm_permanent_flags *pflags;
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				pflags = (struct tpm_permanent_flags *)data;
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				memset(pflags, '\0', sizeof(*pflags));
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				put_unaligned_be32(TPM_TAG_PERMANENT_FLAGS,
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						   &pflags->tag);
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				*recv_len = TPM_HEADER_SIZE + 4 +
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						sizeof(*pflags);
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				break;
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			}
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			default:
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				printf("   ** Unknown flags index %x\n", index);
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				return -ENOSYS;
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			}
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			put_unaligned_be32(*recv_len,
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					   recvbuf +
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					   TPM_RESPONSE_HEADER_LENGTH);
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			break;
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		case TPM_CAP_NV_INDEX:
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			index = get_unaligned_be32(sendbuf + 18);
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			printf("Get cap nv index %#02x\n", index);
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			put_unaligned_be32(22, recvbuf +
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					   TPM_RESPONSE_HEADER_LENGTH);
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			break;
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		default:
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			printf("   ** Unknown 0x65 command type %#02x\n",
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			       type);
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			return -ENOSYS;
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		}
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		break;
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	case TPM_CMD_NV_WRITE_VALUE:
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		index = get_unaligned_be32(sendbuf + 10);
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		length = get_unaligned_be32(sendbuf + 18);
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		seq = index_to_seq(index);
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		if (seq < 0)
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			return -EINVAL;
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		printf("tpm: nvwrite index=%#02x, len=%#02x\n", index, length);
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		memcpy(&tpm->nvdata[seq].data, sendbuf + 22, length);
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		tpm->nvdata[seq].present = true;
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		*recv_len = 12;
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		memset(recvbuf, '\0', *recv_len);
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		break;
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	case TPM_CMD_NV_READ_VALUE: /* nvread */
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		index = get_unaligned_be32(sendbuf + 10);
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		length = get_unaligned_be32(sendbuf + 18);
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		seq = index_to_seq(index);
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		if (seq < 0)
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			return -EINVAL;
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		printf("tpm: nvread index=%#02x, len=%#02x, seq=%#02x\n", index,
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		       length, seq);
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		*recv_len = TPM_RESPONSE_HEADER_LENGTH + sizeof(uint32_t) +
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					length;
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		memset(recvbuf, '\0', *recv_len);
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		put_unaligned_be32(length, recvbuf +
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				   TPM_RESPONSE_HEADER_LENGTH);
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		if (seq == NV_SEQ_KERNEL) {
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			struct rollback_space_kernel rsk;
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			data = recvbuf + TPM_RESPONSE_HEADER_LENGTH +
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					sizeof(uint32_t);
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			memset(&rsk, 0, sizeof(struct rollback_space_kernel));
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			rsk.struct_version = 2;
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			rsk.uid = ROLLBACK_SPACE_KERNEL_UID;
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			rsk.crc8 = crc8(0, (unsigned char *)&rsk,
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					offsetof(struct rollback_space_kernel,
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						 crc8));
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			memcpy(data, &rsk, sizeof(rsk));
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		} else if (!tpm->nvdata[seq].present) {
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			put_unaligned_be32(TPM_BADINDEX, recvbuf +
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					   sizeof(uint16_t) + sizeof(uint32_t));
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		} else {
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			memcpy(recvbuf + TPM_RESPONSE_HEADER_LENGTH +
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			       sizeof(uint32_t), &tpm->nvdata[seq].data,
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			       length);
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		}
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		break;
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	case TPM_CMD_EXTEND:
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		*recv_len = 30;
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		memset(recvbuf, '\0', *recv_len);
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		break;
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	case TPM_CMD_NV_DEFINE_SPACE:
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	case 0x15: /* pcr read */
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	case 0x5d: /* force clear */
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	case 0x6f: /* physical enable */
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	case 0x72: /* physical set deactivated */
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	case 0x99: /* startup */
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	case 0x50: /* self test full */
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	case 0x4000000a:  /* assert physical presence */
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		*recv_len = 12;
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		memset(recvbuf, '\0', *recv_len);
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		break;
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	default:
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		printf("Unknown tpm command %02x\n", code);
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		return -ENOSYS;
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	}
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#ifdef DEBUG
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	printf("tpm: rx recv_len %zd\n", *recv_len);
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	print_buffer(0, recvbuf, 1, *recv_len, 0);
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#endif
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	return 0;
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}
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static int sandbox_tpm_get_desc(struct udevice *dev, char *buf, int size)
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{
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	if (size < 15)
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		return -ENOSPC;
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	return snprintf(buf, size, "sandbox TPM");
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}
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static int sandbox_tpm_probe(struct udevice *dev)
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{
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	struct tpm_state *tpm = dev_get_priv(dev);
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	memcpy(tpm, &g_state, sizeof(*tpm));
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	return 0;
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}
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static int sandbox_tpm_open(struct udevice *dev)
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{
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	return 0;
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}
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static int sandbox_tpm_close(struct udevice *dev)
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{
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	return 0;
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}
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static const struct tpm_ops sandbox_tpm_ops = {
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	.open		= sandbox_tpm_open,
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	.close		= sandbox_tpm_close,
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	.get_desc	= sandbox_tpm_get_desc,
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	.xfer		= sandbox_tpm_xfer,
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};
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static const struct udevice_id sandbox_tpm_ids[] = {
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	{ .compatible = "google,sandbox-tpm" },
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	{ }
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};
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U_BOOT_DRIVER(sandbox_tpm) = {
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	.name   = "sandbox_tpm",
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	.id     = UCLASS_TPM,
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	.of_match = sandbox_tpm_ids,
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	.ops    = &sandbox_tpm_ops,
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	.probe	= sandbox_tpm_probe,
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	.priv_auto_alloc_size = sizeof(struct tpm_state),
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};
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