eMMC: add support for operations in RPMB partition

This patch adds functions for read, write and authentication
key programming for the Replay Protected Memory Block partition
in the eMMC.

Acked-by: Pantelis Antoniou <panto@antoniou-consulting.com>
Signed-off-by: Pierre Aubert <p.aubert@staubli.com>

1 files changed, 323 insertions, 0 deletions

diff --git a/drivers/mmc/rpmb.c b/drivers/mmc/rpmb.c
new file mode 100644
index 0000000..05936f5
--- /dev/null
+++ b/drivers/mmc/rpmb.c
@@ -0,0 +1,323 @@
+/*
+ * Copyright 2014, Staubli Faverges
+ * Pierre Aubert
+ *
+ * eMMC- Replay Protected Memory Block
+ * According to JEDEC Standard No. 84-A441
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <common.h>
+#include <mmc.h>
+#include <sha256.h>
+#include "mmc_private.h"
+
+/* Request codes */
+#define RPMB_REQ_KEY		1
+#define RPMB_REQ_WCOUNTER	2
+#define RPMB_REQ_WRITE_DATA	3
+#define RPMB_REQ_READ_DATA	4
+#define RPMB_REQ_STATUS		5
+
+/* Response code */
+#define RPMB_RESP_KEY		0x0100
+#define RPMB_RESP_WCOUNTER	0x0200
+#define RPMB_RESP_WRITE_DATA	0x0300
+#define RPMB_RESP_READ_DATA	0x0400
+
+/* Error codes */
+#define RPMB_OK			0
+#define RPMB_ERR_GENERAL	1
+#define RPMB_ERR_AUTH	2
+#define RPMB_ERR_COUNTER	3
+#define RPMB_ERR_ADDRESS	4
+#define RPMB_ERR_WRITE		5
+#define RPMB_ERR_READ		6
+#define RPMB_ERR_KEY		7
+#define RPMB_ERR_CNT_EXPIRED	0x80
+#define RPMB_ERR_MSK		0x7
+
+/* Sizes of RPMB data frame */
+#define RPMB_SZ_STUFF		196
+#define RPMB_SZ_MAC		32
+#define RPMB_SZ_DATA		256
+#define RPMB_SZ_NONCE		16
+
+#define SHA256_BLOCK_SIZE	64
+
+/* Error messages */
+static const char * const rpmb_err_msg[] = {
+	"",
+	"General failure",
+	"Authentication failure",
+	"Counter failure",
+	"Address failure",
+	"Write failure",
+	"Read failure",
+	"Authentication key not yet programmed",
+};
+
+
+/* Structure of RPMB data frame. */
+struct s_rpmb {
+	unsigned char stuff[RPMB_SZ_STUFF];
+	unsigned char mac[RPMB_SZ_MAC];
+	unsigned char data[RPMB_SZ_DATA];
+	unsigned char nonce[RPMB_SZ_NONCE];
+	unsigned long write_counter;
+	unsigned short address;
+	unsigned short block_count;
+	unsigned short result;
+	unsigned short request;
+};
+
+static int mmc_set_blockcount(struct mmc *mmc, unsigned int blockcount,
+			      bool is_rel_write)
+{
+	struct mmc_cmd cmd = {0};
+
+	cmd.cmdidx = MMC_CMD_SET_BLOCK_COUNT;
+	cmd.cmdarg = blockcount & 0x0000FFFF;
+	if (is_rel_write)
+		cmd.cmdarg |= 1 << 31;
+	cmd.resp_type = MMC_RSP_R1;
+
+	return mmc_send_cmd(mmc, &cmd, NULL);
+}
+static int mmc_rpmb_request(struct mmc *mmc, const struct s_rpmb *s,
+			    unsigned int count, bool is_rel_write)
+{
+	struct mmc_cmd cmd = {0};
+	struct mmc_data data;
+	int ret;
+
+	ret = mmc_set_blockcount(mmc, count, is_rel_write);
+	if (ret) {
+#ifdef CONFIG_MMC_RPMB_TRACE
+		printf("%s:mmc_set_blockcount-> %d\n", __func__, ret);
+#endif
+		return 1;
+	}
+
+	cmd.cmdidx = MMC_CMD_WRITE_MULTIPLE_BLOCK;
+	cmd.cmdarg = 0;
+	cmd.resp_type = MMC_RSP_R1b;
+
+	data.src = (const char *)s;
+	data.blocks = 1;
+	data.blocksize = MMC_MAX_BLOCK_LEN;
+	data.flags = MMC_DATA_WRITE;
+
+	ret = mmc_send_cmd(mmc, &cmd, &data);
+	if (ret) {
+#ifdef CONFIG_MMC_RPMB_TRACE
+		printf("%s:mmc_send_cmd-> %d\n", __func__, ret);
+#endif
+		return 1;
+	}
+	return 0;
+}
+static int mmc_rpmb_response(struct mmc *mmc, struct s_rpmb *s,
+			     unsigned short expected)
+{
+	struct mmc_cmd cmd = {0};
+	struct mmc_data data;
+	int ret;
+
+	ret = mmc_set_blockcount(mmc, 1, false);
+	if (ret) {
+#ifdef CONFIG_MMC_RPMB_TRACE
+		printf("%s:mmc_set_blockcount-> %d\n", __func__, ret);
+#endif
+		return -1;
+	}
+	cmd.cmdidx = MMC_CMD_READ_MULTIPLE_BLOCK;
+	cmd.cmdarg = 0;
+	cmd.resp_type = MMC_RSP_R1;
+
+	data.dest = (char *)s;
+	data.blocks = 1;
+	data.blocksize = MMC_MAX_BLOCK_LEN;
+	data.flags = MMC_DATA_READ;
+
+	ret = mmc_send_cmd(mmc, &cmd, &data);
+	if (ret) {
+#ifdef CONFIG_MMC_RPMB_TRACE
+		printf("%s:mmc_send_cmd-> %d\n", __func__, ret);
+#endif
+		return -1;
+	}
+	/* Check the response and the status */
+	if (be16_to_cpu(s->request) != expected) {
+#ifdef CONFIG_MMC_RPMB_TRACE
+		printf("%s:response= %x\n", __func__,
+		       be16_to_cpu(s->request));
+#endif
+		return -1;
+	}
+	ret = be16_to_cpu(s->result);
+	if (ret) {
+		printf("%s %s\n", rpmb_err_msg[ret & RPMB_ERR_MSK],
+		       (ret & RPMB_ERR_CNT_EXPIRED) ?
+		       "Write counter has expired" : "");
+	}
+
+	/* Return the status of the command */
+	return ret;
+}
+static int mmc_rpmb_status(struct mmc *mmc, unsigned short expected)
+{
+	ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
+
+	memset(rpmb_frame, 0, sizeof(struct s_rpmb));
+	rpmb_frame->request = cpu_to_be16(RPMB_REQ_STATUS);
+	if (mmc_rpmb_request(mmc, rpmb_frame, 1, false))
+		return -1;
+
+	/* Read the result */
+	return mmc_rpmb_response(mmc, rpmb_frame, expected);
+}
+static void rpmb_hmac(unsigned char *key, unsigned char *buff, int len,
+		      unsigned char *output)
+{
+	sha256_context ctx;
+	int i;
+	unsigned char k_ipad[SHA256_BLOCK_SIZE];
+	unsigned char k_opad[SHA256_BLOCK_SIZE];
+
+	sha256_starts(&ctx);
+
+	/* According to RFC 4634, the HMAC transform looks like:
+	   SHA(K XOR opad, SHA(K XOR ipad, text))
+
+	   where K is an n byte key.
+	   ipad is the byte 0x36 repeated blocksize times
+	   opad is the byte 0x5c repeated blocksize times
+	   and text is the data being protected.
+	*/
+
+	for (i = 0; i < RPMB_SZ_MAC; i++) {
+		k_ipad[i] = key[i] ^ 0x36;
+		k_opad[i] = key[i] ^ 0x5c;
+	}
+	/* remaining pad bytes are '\0' XOR'd with ipad and opad values */
+	for ( ; i < SHA256_BLOCK_SIZE; i++) {
+		k_ipad[i] = 0x36;
+		k_opad[i] = 0x5c;
+	}
+	sha256_update(&ctx, k_ipad, SHA256_BLOCK_SIZE);
+	sha256_update(&ctx, buff, len);
+	sha256_finish(&ctx, output);
+
+	/* Init context for second pass */
+	sha256_starts(&ctx);
+
+	/* start with outer pad */
+	sha256_update(&ctx, k_opad, SHA256_BLOCK_SIZE);
+
+	/* then results of 1st hash */
+	sha256_update(&ctx, output, RPMB_SZ_MAC);
+
+	/* finish up 2nd pass */
+	sha256_finish(&ctx, output);
+}
+int mmc_rpmb_get_counter(struct mmc *mmc, unsigned long *pcounter)
+{
+	int ret;
+	ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
+
+	/* Fill the request */
+	memset(rpmb_frame, 0, sizeof(struct s_rpmb));
+	rpmb_frame->request = cpu_to_be16(RPMB_REQ_WCOUNTER);
+	if (mmc_rpmb_request(mmc, rpmb_frame, 1, false))
+		return -1;
+
+	/* Read the result */
+	ret = mmc_rpmb_response(mmc, rpmb_frame, RPMB_RESP_WCOUNTER);
+	if (ret)
+		return ret;
+
+	*pcounter = be32_to_cpu(rpmb_frame->write_counter);
+	return 0;
+}
+int mmc_rpmb_set_key(struct mmc *mmc, void *key)
+{
+	ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
+	/* Fill the request */
+	memset(rpmb_frame, 0, sizeof(struct s_rpmb));
+	rpmb_frame->request = cpu_to_be16(RPMB_REQ_KEY);
+	memcpy(rpmb_frame->mac, key, RPMB_SZ_MAC);
+
+	if (mmc_rpmb_request(mmc, rpmb_frame, 1, true))
+		return -1;
+
+	/* read the operation status */
+	return mmc_rpmb_status(mmc, RPMB_RESP_KEY);
+}
+int mmc_rpmb_read(struct mmc *mmc, void *addr, unsigned short blk,
+		  unsigned short cnt, unsigned char *key)
+{
+	ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
+	int i;
+
+	for (i = 0; i < cnt; i++) {
+		/* Fill the request */
+		memset(rpmb_frame, 0, sizeof(struct s_rpmb));
+		rpmb_frame->address = cpu_to_be16(blk + i);
+		rpmb_frame->request = cpu_to_be16(RPMB_REQ_READ_DATA);
+		if (mmc_rpmb_request(mmc, rpmb_frame, 1, false))
+			break;
+
+		/* Read the result */
+		if (mmc_rpmb_response(mmc, rpmb_frame, RPMB_RESP_READ_DATA))
+			break;
+
+		/* Check the HMAC if key is provided */
+		if (key) {
+			unsigned char ret_hmac[RPMB_SZ_MAC];
+
+			rpmb_hmac(key, rpmb_frame->data, 284, ret_hmac);
+			if (memcmp(ret_hmac, rpmb_frame->mac, RPMB_SZ_MAC)) {
+				printf("MAC error on block #%d\n", i);
+				break;
+			}
+		}
+		/* Copy data */
+		memcpy(addr + i * RPMB_SZ_DATA, rpmb_frame->data, RPMB_SZ_DATA);
+	}
+	return i;
+}
+int mmc_rpmb_write(struct mmc *mmc, void *addr, unsigned short blk,
+		  unsigned short cnt, unsigned char *key)
+{
+	ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
+	unsigned long wcount;
+	int i;
+
+	for (i = 0; i < cnt; i++) {
+		if (mmc_rpmb_get_counter(mmc, &wcount)) {
+			printf("Cannot read RPMB write counter\n");
+			break;
+		}
+
+		/* Fill the request */
+		memset(rpmb_frame, 0, sizeof(struct s_rpmb));
+		memcpy(rpmb_frame->data, addr + i * RPMB_SZ_DATA, RPMB_SZ_DATA);
+		rpmb_frame->address = cpu_to_be16(blk + i);
+		rpmb_frame->block_count = cpu_to_be16(1);
+		rpmb_frame->write_counter = cpu_to_be32(wcount);
+		rpmb_frame->request = cpu_to_be16(RPMB_REQ_WRITE_DATA);
+		/* Computes HMAC */
+		rpmb_hmac(key, rpmb_frame->data, 284, rpmb_frame->mac);
+
+		if (mmc_rpmb_request(mmc, rpmb_frame, 1, true))
+			break;
+
+		/* Get status */
+		if (mmc_rpmb_status(mmc, RPMB_RESP_WRITE_DATA))
+			break;
+	}
+	return i;
+}