Add Atmel I2C tpm

Add support for Atmel TPM devices with two wire interface.

Signed-off-by: Dirk Eibach <dirk.eibach@gdsys.cc>
Signed-off-by: Reinhard Pfau <reinhard.pfau@gdsys.cc>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Andy Fleming <afleming@freescale.com>

3 files changed, 125 insertions, 0 deletions

diff --git a/README b/README
index 3941725..bcfffc3 100644
--- a/README
+++ b/README
@@ -1238,6 +1238,9 @@ The following options need to be configured:
 			CONFIG_TPM_TIS_I2C_BURST_LIMITATION
 			Define the burst count bytes upper limit
 
+		CONFIG_TPM_ATMEL_TWI
+		Support for Atmel TWI TPM device. Requires I2C support.
+
 		CONFIG_TPM_TIS_LPC
 		Support for generic parallel port TPM devices. Only one device
 		per system is supported at this time.
diff --git a/drivers/tpm/Makefile b/drivers/tpm/Makefile
index 913dd9c..c3010ba 100644
--- a/drivers/tpm/Makefile
+++ b/drivers/tpm/Makefile
@@ -26,6 +26,7 @@ LIB := $(obj)libtpm.o
 $(shell mkdir -p $(obj)slb9635_i2c)
 
 # TODO: Merge tpm_tis_lpc.c with tpm.c
+COBJS-$(CONFIG_TPM_ATMEL_TWI) += tpm_atmel_twi.o
 COBJS-$(CONFIG_TPM_TIS_I2C) += tpm.o
 COBJS-$(CONFIG_TPM_TIS_I2C) += tpm_tis_i2c.o
 COBJS-$(CONFIG_TPM_TIS_LPC) += tpm_tis_lpc.o
diff --git a/drivers/tpm/tpm_atmel_twi.c b/drivers/tpm/tpm_atmel_twi.c
new file mode 100644
index 0000000..361a772
--- /dev/null
+++ b/drivers/tpm/tpm_atmel_twi.c
@@ -0,0 +1,121 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <tpm.h>
+#include <i2c.h>
+#include <asm/unaligned.h>
+
+#define ATMEL_TPM_TIMEOUT_MS 5000 /* sufficient for anything but
+				     generating/exporting keys */
+
+/*
+ * tis_init()
+ *
+ * Initialize the TPM device. Returns 0 on success or -1 on
+ * failure (in case device probing did not succeed).
+ */
+int tis_init(void)
+{
+	return 0;
+}
+
+/*
+ * tis_open()
+ *
+ * Requests access to locality 0 for the caller. After all commands have been
+ * completed the caller is supposed to call tis_close().
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+int tis_open(void)
+{
+	return 0;
+}
+
+/*
+ * tis_close()
+ *
+ * terminate the currect session with the TPM by releasing the locked
+ * locality. Returns 0 on success of -1 on failure (in case lock
+ * removal did not succeed).
+ */
+int tis_close(void)
+{
+	return 0;
+}
+
+/*
+ * tis_sendrecv()
+ *
+ * Send the requested data to the TPM and then try to get its response
+ *
+ * @sendbuf - buffer of the data to send
+ * @send_size size of the data to send
+ * @recvbuf - memory to save the response to
+ * @recv_len - pointer to the size of the response buffer
+ *
+ * Returns 0 on success (and places the number of response bytes at recv_len)
+ * or -1 on failure.
+ */
+int tis_sendrecv(const uint8_t *sendbuf, size_t send_size, uint8_t *recvbuf,
+			size_t *recv_len)
+{
+	int res;
+	unsigned long start;
+
+#ifdef DEBUG
+	memset(recvbuf, 0xcc, *recv_len);
+	printf("send to TPM (%d bytes, recv_len=%d):\n", send_size, *recv_len);
+	print_buffer(0, (void *)sendbuf, 1, send_size, 0);
+#endif
+
+	res = i2c_write(0x29, 0, 0, (uchar *)sendbuf, send_size);
+	if (res) {
+		printf("i2c_write returned %d\n", res);
+		return -1;
+	}
+
+	start = get_timer(0);
+	while ((res = i2c_read(0x29, 0, 0, recvbuf, 10))) {
+		if (get_timer(start) > ATMEL_TPM_TIMEOUT_MS) {
+			puts("tpm timed out\n");
+			return -1;
+		}
+		udelay(100);
+	}
+	if (!res) {
+		*recv_len = get_unaligned_be32(recvbuf + 2);
+		if (*recv_len > 10)
+			res = i2c_read(0x29, 0, 0, recvbuf, *recv_len);
+	}
+	if (res) {
+		printf("i2c_read returned %d (rlen=%d)\n", res, *recv_len);
+#ifdef DEBUG
+		print_buffer(0, recvbuf, 1, *recv_len, 0);
+#endif
+	}
+
+#ifdef DEBUG
+	if (!res) {
+		printf("read from TPM (%d bytes):\n", *recv_len);
+		print_buffer(0, recvbuf, 1, *recv_len, 0);
+	}
+#endif
+
+	return res;
+}