[PATCHv2] drivers: tee: i2c trampoline driver

* [PATCHv2] drivers: tee: i2c trampoline driver
@ 2020-12-28 12:17 Jorge Ramirez-Ortiz
  2020-12-29  3:32 ` Simon Glass
  0 siblings, 1 reply; 3+ messages in thread
From: Jorge Ramirez-Ortiz @ 2020-12-28 12:17 UTC (permalink / raw)
  To: u-boot

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).

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            | 21 ++++++
 drivers/tee/optee/optee_msg_supplicant.h |  5 ++
 drivers/tee/optee/optee_private.h        | 12 ++++
 drivers/tee/optee/supplicant.c           |  3 +
 6 files changed, 130 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..506e40850c
--- /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 u8 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.rmem.size;
+	shm = (struct tee_shm *)(unsigned long)arg->params[2].u.rmem.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..8d40ce60c2 100644
--- a/drivers/tee/optee/optee_msg.h
+++ b/drivers/tee/optee/optee_msg.h
@@ -422,4 +422,25 @@ 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/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..fc19e97871 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
+static 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

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