Message-Id: <20231030095849.3456820-10-pankaj.gupta@nxp.com>
Date:   Mon, 30 Oct 2023 15:28:47 +0530
From:   Pankaj Gupta <pankaj.gupta@....com>
To:     shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de,
        clin@...e.com, conor+dt@...nel.org, pierre.gondois@....com,
        festevam@...il.com, linux-imx@....com, davem@...emloft.net,
        robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, gaurav.jain@....com,
        alexander.stein@...tq-group.com, V.Sethi@....com
Cc:     Pankaj Gupta <pankaj.gupta@....com>
Subject: [PATCH v7 09/11] firmware: imx: enable trng

Enabled trng on imx93 platform through enclave fw.

Signed-off-by: Gaurav Jain <gaurav.jain@....com>
Signed-off-by: Pankaj Gupta <pankaj.gupta@....com>
---
 drivers/firmware/imx/Kconfig              |   9 ++
 drivers/firmware/imx/Makefile             |   1 +
 drivers/firmware/imx/ele_base_msg.c       | 117 ++++++++++++++++++++++
 drivers/firmware/imx/ele_common.c         |  40 ++++++++
 drivers/firmware/imx/ele_common.h         |   2 +
 drivers/firmware/imx/ele_fw_api.c         |  67 +++++++++++++
 drivers/firmware/imx/ele_fw_api.h         |   6 ++
 drivers/firmware/imx/ele_trng.c           |  47 +++++++++
 drivers/firmware/imx/se_fw.c              |  21 ++++
 include/linux/firmware/imx/ele_base_msg.h |  13 +++
 10 files changed, 323 insertions(+)
 create mode 100644 drivers/firmware/imx/ele_trng.c

diff --git a/drivers/firmware/imx/Kconfig b/drivers/firmware/imx/Kconfig
index 2822e5d4b24c..ffc02593293c 100644
--- a/drivers/firmware/imx/Kconfig
+++ b/drivers/firmware/imx/Kconfig
@@ -40,3 +40,12 @@ config IMX_SEC_ENCLAVE
           like base, HSM, V2X & SHE using the SAB protocol via the shared Messaging
           Unit. This driver exposes these interfaces via a set of file descriptors
           allowing to configure shared memory, send and receive messages.
+
+config IMX_ELE_TRNG
+	tristate "i.MX ELE True Random Number Generator"
+	default y
+	select CRYPTO_RNG
+	select HW_RANDOM
+	help
+	  This driver provides kernel-side support for the Random Number generation,
+          through NXP hardware IP for secure-enclave called EdgeLock Enclave.
diff --git a/drivers/firmware/imx/Makefile b/drivers/firmware/imx/Makefile
index d61f06a8050a..9018f7824f36 100644
--- a/drivers/firmware/imx/Makefile
+++ b/drivers/firmware/imx/Makefile
@@ -3,3 +3,4 @@ obj-$(CONFIG_IMX_DSP)		+= imx-dsp.o
 obj-$(CONFIG_IMX_SCU)		+= imx-scu.o misc.o imx-scu-irq.o rm.o imx-scu-soc.o
 sec_enclave-objs		= se_fw.o ele_common.o ele_base_msg.o ele_fw_api.o
 obj-${CONFIG_IMX_SEC_ENCLAVE}	+= sec_enclave.o
+sec_enclave-${CONFIG_IMX_ELE_TRNG} += ele_trng.o
diff --git a/drivers/firmware/imx/ele_base_msg.c b/drivers/firmware/imx/ele_base_msg.c
index 813f769f7bc3..3a3af2321f67 100644
--- a/drivers/firmware/imx/ele_base_msg.c
+++ b/drivers/firmware/imx/ele_base_msg.c
@@ -99,3 +99,120 @@ int ele_ping(struct device *dev)
 
 	return ret;
 }
+
+/*
+ * ele_get_trng_state() - prepare and send the command to read
+ *                        crypto lib and TRNG state
+ * TRNG state
+ *  0x1		TRNG is in program mode
+ *  0x2		TRNG is still generating entropy
+ *  0x3		TRNG entropy is valid and ready to be read
+ *  0x4		TRNG encounter an error while generating entropy
+ *
+ * CSAL state
+ *  0x0		Crypto Lib random context initialization is not done yet
+ *  0x1		Crypto Lib random context initialization is on-going
+ *  0x2		Crypto Lib random context initialization succeed
+ *  0x3		Crypto Lib random context initialization failed
+ *
+ * returns: csal and trng state.
+ *
+ */
+int ele_get_trng_state(struct device *dev)
+{
+	struct ele_mu_priv *priv = dev_get_drvdata(dev);
+	int ret;
+	unsigned int status;
+
+	ret = imx_se_alloc_tx_rx_buf(priv);
+	if (ret)
+		return ret;
+
+	ret = plat_fill_cmd_msg_hdr(priv,
+				    (struct mu_hdr *)&priv->tx_msg->header,
+				    ELE_GET_TRNG_STATE_REQ,
+				    ELE_GET_TRNG_STATE_REQ_MSG_SZ,
+				    true);
+	if (ret) {
+		pr_err("Error: plat_fill_cmd_msg_hdr failed.\n");
+		goto exit;
+	}
+
+	ret = imx_ele_msg_send_rcv(priv);
+	if (ret)
+		goto exit;
+
+	ret = imx_ele_msg_send_rcv(priv);
+	if (ret < 0)
+		goto exit;
+
+	ret  = validate_rsp_hdr(priv,
+				priv->rx_msg->header,
+				ELE_GET_TRNG_STATE_REQ,
+				ELE_GET_TRNG_STATE_RSP_MSG_SZ,
+				true);
+	if (ret)
+		goto exit;
+
+	status = RES_STATUS(priv->rx_msg->data[0]);
+	if (status != priv->success_tag) {
+		dev_err(dev, "Command Id[%d], Response Failure = 0x%x",
+			ELE_GET_TRNG_STATE_REQ, status);
+		ret = -1;
+	} else
+		ret = (priv->rx_msg->data[1] & CSAL_TRNG_STATE_MASK);
+
+exit:
+	imx_se_free_tx_rx_buf(priv);
+
+	return ret;
+}
+
+/*
+ * ele_start_rng() - prepare and send the command to start
+ *                   initialization of the ELE RNG context
+ *
+ * returns:  0 on success.
+ */
+int ele_start_rng(struct device *dev)
+{
+	struct ele_mu_priv *priv = dev_get_drvdata(dev);
+	int ret;
+	unsigned int status;
+
+	ret = imx_se_alloc_tx_rx_buf(priv);
+	if (ret)
+		return ret;
+
+	ret = plat_fill_cmd_msg_hdr(priv,
+				    (struct mu_hdr *)&priv->tx_msg->header,
+				    ELE_START_RNG_REQ,
+				    ELE_START_RNG_REQ_MSG_SZ,
+				    true);
+	if (ret)
+		goto exit;
+
+	ret = imx_ele_msg_send_rcv(priv);
+	if (ret < 0)
+		goto exit;
+
+	ret  = validate_rsp_hdr(priv,
+				priv->rx_msg->header,
+				ELE_START_RNG_REQ,
+				ELE_START_RNG_RSP_MSG_SZ,
+				true);
+	if (ret)
+		goto exit;
+
+	status = RES_STATUS(priv->rx_msg->data[0]);
+	if (status != priv->success_tag) {
+		dev_err(dev, "Command Id[%d], Response Failure = 0x%x",
+			ELE_START_RNG_REQ, status);
+		ret = -1;
+	}
+
+exit:
+	imx_se_free_tx_rx_buf(priv);
+
+	return ret;
+}
diff --git a/drivers/firmware/imx/ele_common.c b/drivers/firmware/imx/ele_common.c
index 4410245a19ec..d4b829c19133 100644
--- a/drivers/firmware/imx/ele_common.c
+++ b/drivers/firmware/imx/ele_common.c
@@ -3,6 +3,10 @@
  * Copyright 2023 NXP
  */
 
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/firmware/imx/ele_base_msg.h>
+
 #include "ele_common.h"
 #include "se_fw.h"
 
@@ -137,3 +141,39 @@ int validate_rsp_hdr(struct ele_mu_priv *priv, unsigned int header,
 
 	return ret;
 }
+
+int ele_do_start_rng(struct device *dev)
+{
+	int ret;
+	int count = ELE_GET_TRNG_STATE_RETRY_COUNT;
+
+	ret = ele_get_trng_state(dev);
+	if (ret < 0) {
+		dev_err(dev, "Failed to get trng state\n");
+		return ret;
+	} else if (ret != ELE_TRNG_STATE_OK) {
+		/* call start rng */
+		ret = ele_start_rng(dev);
+		if (ret) {
+			dev_err(dev, "Failed to start rng\n");
+			return ret;
+		}
+
+		/* poll get trng state API, ELE_GET_TRNG_STATE_RETRY_COUNT times
+		 * or while trng state != 0x203
+		 */
+		do {
+			msleep(10);
+			ret = ele_get_trng_state(dev);
+			if (ret < 0) {
+				dev_err(dev, "Failed to get trng state\n");
+				return ret;
+			}
+			count--;
+		} while ((ret != ELE_TRNG_STATE_OK) && count);
+		if (ret != ELE_TRNG_STATE_OK)
+			return -EIO;
+	}
+
+	return 0;
+}
diff --git a/drivers/firmware/imx/ele_common.h b/drivers/firmware/imx/ele_common.h
index 284b7f66d8e3..f9e1d949dc6a 100644
--- a/drivers/firmware/imx/ele_common.h
+++ b/drivers/firmware/imx/ele_common.h
@@ -27,4 +27,6 @@ static inline int ele_trng_init(struct device *dev)
 	return 0;
 }
 #endif
+
+int ele_do_start_rng(struct device *dev);
 #endif
diff --git a/drivers/firmware/imx/ele_fw_api.c b/drivers/firmware/imx/ele_fw_api.c
index 55dda9d6531a..d195a920b3ee 100644
--- a/drivers/firmware/imx/ele_fw_api.c
+++ b/drivers/firmware/imx/ele_fw_api.c
@@ -49,3 +49,70 @@ int ele_init_fw(struct device *dev)
 
 	return ret;
 }
+
+/*
+ * ele_get_random() - prepare and send the command to proceed
+ *                    with a random number generation operation
+ *
+ * returns:  size of the rondom number generated
+ */
+int ele_get_random(struct device *dev,
+		   void *data, size_t len)
+{
+	struct ele_mu_priv *priv = dev_get_drvdata(dev);
+	unsigned int status;
+	dma_addr_t dst_dma;
+	u8 *buf;
+	int ret;
+
+	buf = dmam_alloc_coherent(priv->dev, len, &dst_dma, GFP_KERNEL);
+	if (!buf) {
+		dev_err(priv->dev, "Failed to map destination buffer memory\n");
+		return -ENOMEM;
+	}
+
+	ret = imx_se_alloc_tx_rx_buf(priv);
+	if (ret) {
+		ret = -ENOMEM;
+		goto exit1;
+	}
+
+	ret = plat_fill_cmd_msg_hdr(priv,
+				    (struct mu_hdr *)&priv->tx_msg->header,
+				    ELE_GET_RANDOM_REQ, ELE_GET_RANDOM_REQ_SZ,
+				    false);
+	if (ret)
+		goto exit;
+
+	priv->tx_msg->data[0] = 0x0;
+	priv->tx_msg->data[1] = dst_dma;
+	priv->tx_msg->data[2] = len;
+	ret = imx_ele_msg_send_rcv(priv);
+	if (ret < 0)
+		goto exit;
+
+	ret  = validate_rsp_hdr(priv,
+				priv->rx_msg->header,
+				ELE_GET_RANDOM_REQ,
+				ELE_GET_RANDOM_RSP_SZ,
+				false);
+	if (ret)
+		return ret;
+
+	status = RES_STATUS(priv->rx_msg->data[0]);
+	if (status != priv->success_tag) {
+		dev_err(dev, "Command Id[%d], Response Failure = 0x%x",
+			ELE_GET_RANDOM_REQ, status);
+		ret = -1;
+	} else {
+		memcpy(data, buf, len);
+		ret = len;
+	}
+
+exit:
+	imx_se_free_tx_rx_buf(priv);
+exit1:
+	dmam_free_coherent(priv->dev, len, buf, dst_dma);
+
+	return ret;
+}
diff --git a/drivers/firmware/imx/ele_fw_api.h b/drivers/firmware/imx/ele_fw_api.h
index 21bb35b4041f..70cd8cf5074b 100644
--- a/drivers/firmware/imx/ele_fw_api.h
+++ b/drivers/firmware/imx/ele_fw_api.h
@@ -14,7 +14,13 @@
 #define ELE_INIT_FW_REQ_SZ              0x04
 #define ELE_INIT_FW_RSP_SZ              0x08
 
+#define ELE_GET_RANDOM_REQ		0xCD
+#define ELE_GET_RANDOM_REQ_SZ		0x10
+#define ELE_GET_RANDOM_RSP_SZ		0x08
+
 
 int ele_init_fw(struct device *dev);
+int ele_get_random(struct device *dev, void *data, size_t len);
+int ele_get_hwrng(struct hwrng *rng, void *data, size_t len, bool wait);
 
 #endif /* ELE_FW_API_H */
diff --git a/drivers/firmware/imx/ele_trng.c b/drivers/firmware/imx/ele_trng.c
new file mode 100644
index 000000000000..4a7a119ff435
--- /dev/null
+++ b/drivers/firmware/imx/ele_trng.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ELE Random Number Generator Driver NXP's Platforms
+ *
+ * Copyright 2023 NXP
+ */
+
+#include "ele_common.h"
+#include "ele_fw_api.h"
+
+struct ele_trng {
+	struct hwrng rng;
+	struct device *dev;
+};
+
+int ele_trng_init(struct device *dev)
+{
+	struct ele_trng *trng;
+	int ret;
+
+	trng = devm_kzalloc(dev, sizeof(*trng), GFP_KERNEL);
+	if (!trng)
+		return -ENOMEM;
+
+	trng->dev         = dev;
+	trng->rng.name    = "ele-trng";
+	trng->rng.read    = ele_get_hwrng;
+	trng->rng.priv    = (unsigned long)trng;
+	trng->rng.quality = 1024;
+
+	dev_dbg(dev, "registering ele-trng\n");
+
+	ret = devm_hwrng_register(dev, &trng->rng);
+	if (ret)
+		return ret;
+
+	dev_info(dev, "Successfully registered ele-trng\n");
+	return 0;
+}
+
+int ele_get_hwrng(struct hwrng *rng,
+		  void *data, size_t len, bool wait)
+{
+	struct ele_trng *trng = (struct ele_trng *)rng->priv;
+
+	return ele_get_random(trng->dev, data, len);
+}
diff --git a/drivers/firmware/imx/se_fw.c b/drivers/firmware/imx/se_fw.c
index 92dc8ea58960..3638a4fed5e7 100644
--- a/drivers/firmware/imx/se_fw.c
+++ b/drivers/firmware/imx/se_fw.c
@@ -24,6 +24,7 @@
 #include <linux/sys_soc.h>
 
 #include "se_fw.h"
+#include "ele_common.h"
 #include "ele_fw_api.h"
 
 #define SOC_ID_OF_IMX8ULP		0x084D
@@ -48,6 +49,9 @@ struct imx_info {
 	uint8_t *pool_name;
 	bool reserved_dma_ranges;
 	bool init_fw;
+	/* platform specific flag to enable/disable the ELE True RNG */
+	bool start_rng;
+	bool enable_ele_trng;
 };
 
 struct imx_info_list {
@@ -76,6 +80,8 @@ static const struct imx_info_list imx8ulp_info = {
 				.pool_name = "sram",
 				.reserved_dma_ranges = true,
 				.init_fw = false,
+				.start_rng = true,
+				.enable_ele_trng = false,
 			},
 	},
 };
@@ -99,6 +105,8 @@ static const struct imx_info_list imx93_info = {
 				.pool_name = NULL,
 				.reserved_dma_ranges = true,
 				.init_fw = true,
+				.start_rng = true,
+				.enable_ele_trng = true,
 			},
 	},
 };
@@ -1260,6 +1268,19 @@ static int se_fw_probe(struct platform_device *pdev)
 	if (ret)
 		dev_err(dev, "Failed[%d] to ping the fw.\n", ret);
 
+	/* start ele rng */
+	if (info->start_rng) {
+		ret = ele_do_start_rng(dev);
+		if (ret)
+			dev_err(dev, "Failed to start ele rng\n");
+	}
+
+	if (!ret && info->enable_ele_trng) {
+		ret = ele_trng_init(dev);
+		if (ret)
+			dev_err(dev, "Failed to init ele-trng\n");
+	}
+
 	dev_info(dev, "i.MX secure-enclave: %s interface to firmware, configured.\n",
 		info->pdev_name[1]);
 
diff --git a/include/linux/firmware/imx/ele_base_msg.h b/include/linux/firmware/imx/ele_base_msg.h
index 49e3619372be..3ca4b47e4c4e 100644
--- a/include/linux/firmware/imx/ele_base_msg.h
+++ b/include/linux/firmware/imx/ele_base_msg.h
@@ -34,7 +34,20 @@
 #define ELE_PING_REQ_SZ			0x04
 #define ELE_PING_RSP_SZ			0x08
 
+#define ELE_START_RNG_REQ		0xA3
+#define ELE_START_RNG_REQ_MSG_SZ	0x04
+#define ELE_START_RNG_RSP_MSG_SZ	0x08
+
+#define ELE_GET_TRNG_STATE_REQ		0xA4
+#define ELE_GET_TRNG_STATE_REQ_MSG_SZ	0x04
+#define ELE_GET_TRNG_STATE_RSP_MSG_SZ	0x0C
+#define ELE_TRNG_STATE_OK		0x203
+#define ELE_GET_TRNG_STATE_RETRY_COUNT	0x5
+#define CSAL_TRNG_STATE_MASK		0x0000ffff
+
 int ele_get_info(struct device *dev, phys_addr_t addr, u32 data_size);
 int ele_ping(struct device *dev);
+int ele_start_rng(struct device *dev);
+int ele_get_trng_state(struct device *dev);
 
 #endif
-- 
2.34.1

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