[PATCH] drivers: tee: i2c trampoline driver

Jorge Ramirez-Ortiz
2020-12-21T18:15:40Z

This commit gives the secure world access to the I2C bus so it can
communicate with I2C slaves (tipically those would be secure elements
like the NXP SE050).

Tested on imx8mmevk.

Signed-off-by: Jorge Ramirez-Ortiz <jorge@foundries.io>
---
drivers/tee/optee/Makefile | 1 +
drivers/tee/optee/i2c.c | 88 ++++++++++++++++++++++++
drivers/tee/optee/optee_msg.h | 22 ++++++
drivers/tee/optee/optee_msg_supplicant.h | 5 ++
drivers/tee/optee/optee_private.h | 12 ++++
drivers/tee/optee/supplicant.c | 3 +
6 files changed, 131 insertions(+)
create mode 100644 drivers/tee/optee/i2c.c

diff --git a/drivers/tee/optee/Makefile b/drivers/tee/optee/Makefile
index 928d3f8002..068c6e7aa1 100644
--- a/drivers/tee/optee/Makefile
+++ b/drivers/tee/optee/Makefile
@@ -2,4 +2,5 @@

obj-y += core.o
obj-y += supplicant.o
+obj-$(CONFIG_DM_I2C) += i2c.o
obj-$(CONFIG_SUPPORT_EMMC_RPMB) += rpmb.o
diff --git a/drivers/tee/optee/i2c.c b/drivers/tee/optee/i2c.c
new file mode 100644
index 0000000000..2ebbf1ff7c
--- /dev/null
+++ b/drivers/tee/optee/i2c.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * Copyright (c) 2020 Foundries.io Ltd
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <i2c.h>
+#include <tee.h>
+#include "optee_msg.h"
+#include "optee_private.h"
+
+static struct {
+ struct udevice *dev;
+ int chip;
+ int bus;
+} xfer;
+
+void optee_suppl_cmd_i2c_transfer(struct udevice *dev,
+ struct optee_msg_arg *arg)
+{
+ const uint64_t attr[] = {
+ OPTEE_MSG_ATTR_TYPE_VALUE_INPUT,
+ OPTEE_MSG_ATTR_TYPE_VALUE_INPUT,
+ OPTEE_MSG_ATTR_TYPE_RMEM_INOUT,
+ OPTEE_MSG_ATTR_TYPE_VALUE_OUTPUT,
+ };
+ struct udevice *chip_dev = NULL;
+ struct tee_shm *shm = NULL;
+ uint8_t *buf = NULL;
+ size_t len = 0;
+ int chip = -1;
+ int bus = -1;
+ int ret = -1;
+
+ if (arg->num_params != ARRAY_SIZE(attr) ||
+ arg->params[0].attr != attr[0] ||
+ arg->params[1].attr != attr[1] ||
+ arg->params[2].attr != attr[2] ||
+ arg->params[3].attr != attr[3]) {
+ arg->ret = TEE_ERROR_BAD_PARAMETERS;
+ return;
+ }
+
+ len = arg->params[2].u.tmem.size;
+ shm = (struct tee_shm *)(unsigned long)arg->params[2].u.tmem.shm_ref;
+ buf = shm->addr;
+ if (!buf || !len)
+ goto bad;
+
+ bus = (int)arg->params[0].u.value.b;
+ chip = (int)arg->params[0].u.value.c;
+
+ if (!xfer.dev || xfer.chip != chip || xfer.bus != bus) {
+ if (i2c_get_chip_for_busnum(bus, chip, 0, &chip_dev))
+ goto bad;
+
+ xfer.dev = chip_dev;
+ xfer.chip = chip;
+ xfer.bus = bus;
+ }
+
+ if (arg->params[1].u.value.a & OPTEE_MSG_RPC_CMD_I2C_FLAGS_TEN_BIT)
+ if (i2c_set_chip_flags(xfer.dev, DM_I2C_CHIP_10BIT))
+ goto bad;
+
+ switch (arg->params[0].u.value.a) {
+ case OPTEE_MSG_RPC_CMD_I2C_TRANSFER_RD:
+ ret = dm_i2c_read(xfer.dev, 0, buf, len);
+ break;
+ case OPTEE_MSG_RPC_CMD_I2C_TRANSFER_WR:
+ ret = dm_i2c_write(xfer.dev, 0, buf, len);
+ break;
+ default:
+ goto bad;
+ }
+
+ if (ret) {
+ arg->ret = TEE_ERROR_COMMUNICATION;
+ } else {
+ arg->params[3].u.value.a = len;
+ arg->ret = TEE_SUCCESS;
+ }
+
+ return;
+bad:
+ arg->ret = TEE_ERROR_BAD_PARAMETERS;
+}
diff --git a/drivers/tee/optee/optee_msg.h b/drivers/tee/optee/optee_msg.h
index 24c60960fc..7cedb59a82 100644
--- a/drivers/tee/optee/optee_msg.h
+++ b/drivers/tee/optee/optee_msg.h
@@ -422,4 +422,26 @@ struct optee_msg_arg {
*/
#define OPTEE_MSG_RPC_CMD_SHM_FREE 7

+/*
+ * Access a device on an i2c bus
+ *
+ * [in] param[0].u.value.a mode: RD(0), WR(1)
+ * [in] param[0].u.value.b i2c adapter
+ * [in] param[0].u.value.c i2c chip
+ *
+ * [in] param[1].u.value.a i2c control flags
+ * [in] param[1].u.value.b i2c retry (optional)
+ *
+ * [in/out] memref[2] buffer to exchange the transfer data
+ * with the secure world
+ *
+ * [out] param[3].u.value.a bytes transferred by the driver
+ */
+#define OPTEE_MSG_RPC_CMD_I2C_TRANSFER 21
+/* I2C master transfer modes */
+#define OPTEE_MSG_RPC_CMD_I2C_TRANSFER_RD 0
+#define OPTEE_MSG_RPC_CMD_I2C_TRANSFER_WR 1
+/* I2C master control flags */
+#define OPTEE_MSG_RPC_CMD_I2C_FLAGS_TEN_BIT BIT(0)
+
#endif /* _OPTEE_MSG_H */
diff --git a/drivers/tee/optee/optee_msg_supplicant.h b/drivers/tee/optee/optee_msg_supplicant.h
index a0fb8063c8..963cfd4782 100644
--- a/drivers/tee/optee/optee_msg_supplicant.h
+++ b/drivers/tee/optee/optee_msg_supplicant.h
@@ -147,6 +147,11 @@
#define OPTEE_MSG_RPC_CMD_SHM_ALLOC 6
#define OPTEE_MSG_RPC_CMD_SHM_FREE 7

+/*
+ * I2C bus access
+ */
+#define OPTEE_MSG_RPC_CMD_I2C_TRANSFER 21
+
/*
* Was OPTEE_MSG_RPC_CMD_SQL_FS, which isn't supported any longer
*/
diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
index 9442d1c176..d7ab1f593f 100644
--- a/drivers/tee/optee/optee_private.h
+++ b/drivers/tee/optee/optee_private.h
@@ -60,6 +60,18 @@ static inline void optee_suppl_rpmb_release(struct udevice *dev)
}
#endif

+#ifdef CONFIG_DM_I2C
+void optee_suppl_cmd_i2c_transfer(struct udevice *dev,
+ struct optee_msg_arg *arg);
+#else
+void optee_suppl_cmd_i2c_transfer(struct udevice *dev,
+ struct optee_msg_arg *arg)
+{
+ debug("OPTEE_MSG_RPC_CMD_I2C_TRANSFER not implemented\n");
+ arg->ret = TEE_ERROR_NOT_IMPLEMENTED;
+}
+#endif
+
void *optee_alloc_and_init_page_list(void *buf, ulong len, u64 *phys_buf_ptr);

#endif /* __OPTEE_PRIVATE_H */
diff --git a/drivers/tee/optee/supplicant.c b/drivers/tee/optee/supplicant.c
index ae042b9a20..f7738983cd 100644
--- a/drivers/tee/optee/supplicant.c
+++ b/drivers/tee/optee/supplicant.c
@@ -89,6 +89,9 @@ void optee_suppl_cmd(struct udevice *dev, struct tee_shm *shm_arg,
case OPTEE_MSG_RPC_CMD_RPMB:
optee_suppl_cmd_rpmb(dev, arg);
break;
+ case OPTEE_MSG_RPC_CMD_I2C_TRANSFER:
+ optee_suppl_cmd_i2c_transfer(dev, arg);
+ break;
default:
arg->ret = TEE_ERROR_NOT_IMPLEMENTED;
}
--
2.17.1