cr50: make use of byteorder routinesstabilize-7647.74.Bstabilize-7647.72.Bstabilize-7647.32.Brelease-R48-7647.B

Use the previously introduced endian conversion routines in the driver
and the TPM2 library.

Use packed TPM message header structure to make it easy to access
unaligned header fields.

BRANCH=none
BUG=chrome-os-partner:43025
TEST=the tpm startup command still succeeds.

Change-Id: I03078481664858a19617e248f98cb20013c27445
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/312585

4 files changed, 30 insertions, 52 deletions

diff --git a/board/cr50/build.mk b/board/cr50/build.mk
index 7cdc079bde..d2fe6309bd 100644
--- a/board/cr50/build.mk
+++ b/board/cr50/build.mk
@@ -40,6 +40,10 @@ EXTLIB := $(realpath ../../third_party/tpm2)
 CFLAGS += -I$(EXTLIB)
 LDFLAGS_EXTRA += -L$(out)/tpm2 -ltpm2
 
+# For the benefit of the tpm2 library.
+INCLUDE_ROOT := $(abspath ./include)
+CFLAGS += -I$(INCLUDE_ROOT)
+
 # Add dependencies on that library
 $(out)/RO/ec.RO.elf: $(out)/tpm2/libtpm2.a
 $(out)/RW/ec.RW.elf: $(out)/tpm2/libtpm2.a
diff --git a/board/cr50/tpm2/endian.h b/board/cr50/tpm2/endian.h
index 893a794c16..b5b64d3bea 100644
--- a/board/cr50/tpm2/endian.h
+++ b/board/cr50/tpm2/endian.h
@@ -6,43 +6,6 @@
 #ifndef __EC_BOARD_CR50_TPM2_ENDIAN_H
 #define __EC_BOARD_CR50_TPM2_ENDIAN_H
 
-#include <stddef.h>
-#include <stdint.h>
-
-static inline void swap_n(void *in, void *out, size_t size)
-{
-	int i;
-
-	for (i = 0; i < size; i++)
-		((uint8_t *)out)[size - i - 1] = ((uint8_t *)in)[i];
-}
-
-static inline uint16_t be16toh(uint16_t in)
-{
-	uint16_t out;
-
-	swap_n(&in, &out, sizeof(out));
-	return out;
-}
-
-static inline uint32_t be32toh(uint32_t in)
-{
-	uint32_t out;
-
-	swap_n(&in, &out, sizeof(out));
-	return out;
-}
-
-static inline uint64_t be64toh(uint64_t in)
-{
-	uint64_t out;
-
-	swap_n(&in, &out, sizeof(out));
-	return out;
-}
-
-#define htobe16 be16toh
-#define htobe32 be32toh
-#define htobe64 be64toh
+#include "byteorder.h"
 
 #endif /* __EC_BOARD_CR50_TPM2_ENDIAN_H */
diff --git a/common/tpm_registers.c b/common/tpm_registers.c
index 5aba839764..52de4aa6f6 100644
--- a/common/tpm_registers.c
+++ b/common/tpm_registers.c
@@ -9,6 +9,7 @@
  * 24-bit address. There is no provision for error reporting at this level.
  */
 
+#include "byteorder.h"
 #include "common.h"
 #include "console.h"
 #include "hooks.h"
@@ -273,22 +274,12 @@ static void sts_reg_write(const uint8_t *data, uint32_t data_size)
 	}
 }
 
-/* We presume to be running on a little endian CPU. */
-static uint32_t be32_to_cpu(const uint8_t *data)
-{
-	int i;
-	uint32_t value = 0;
-
-	for (i = 0; i < sizeof(value); i++)
-		value |= ((uint32_t)data[i]) << (8 * (sizeof(value) - i - 1));
-
-	return value;
-}
-
 /* Collect received data in the local buffer and change state accordingly. */
 static void fifo_reg_write(const uint8_t *data, uint32_t data_size)
 {
 	uint32_t packet_size;
+	struct tpm_cmd_header *tpmh;
+
 	/*
 	 * Make sure we are in the approriate sate, otherwise ignore this
 	 * access.
@@ -322,7 +313,8 @@ static void fifo_reg_write(const uint8_t *data, uint32_t data_size)
 		return;
 	}
 
-	packet_size = be32_to_cpu(tpm_.regs.data_fifo + 2);
+	tpmh = (struct tpm_cmd_header *)tpm_.regs.data_fifo;
+	packet_size = be32toh(tpmh->size);
 	if (tpm_.fifo_write_index < packet_size) {
 		tpm_.regs.sts |= expect; /* More data is needed. */
 		return;
@@ -427,11 +419,15 @@ void tpm_task(void)
 	while (1) {
 		uint8_t *response;
 		unsigned response_size;
+		uint32_t command_code;
+		struct tpm_cmd_header *tpmh;
 
 		/* Wait for the next command event */
 		task_wait_event(-1);
+		tpmh = (struct tpm_cmd_header *)tpm_.regs.data_fifo;
+		command_code = be32toh(tpmh->command_code);
 		CPRINTF("%s: received fifo command 0x%04x\n",
-			__func__, be32_to_cpu(tpm_.regs.data_fifo + 6));
+			__func__, command_code);
 
 		ExecuteCommand(tpm_.fifo_write_index,
 			       tpm_.regs.data_fifo,
diff --git a/include/tpm_registers.h b/include/tpm_registers.h
index 2bdd87bc25..ea8011bfed 100644
--- a/include/tpm_registers.h
+++ b/include/tpm_registers.h
@@ -14,6 +14,8 @@
 
 #include <stdint.h>
 
+#include "common.h"
+
 /* The SPI master is writing data into a TPM register. */
 void tpm_register_put(uint32_t regaddr,
 		      const uint8_t *data, uint32_t data_size);
@@ -24,4 +26,17 @@ void tpm_register_get(uint32_t regaddr, uint8_t *dest, uint32_t data_size);
 /* Enable SPS TPM driver. */
 void sps_tpm_enable(void);
 
+/*
+ * This structure describes the header of all commands and responses sent and
+ * received over TPM FIFO.
+ *
+ * Note that all fields are stored in the network (big endian) byte order.
+ */
+
+struct tpm_cmd_header {
+	uint16_t tag;
+	uint32_t size;
+	uint32_t command_code;
+} __packed;
+
 #endif	/* __CROS_EC_TPM_REGISTERS_H */