Re: [PATCH v6 4/5] firmware: imx: add driver for NXP EdgeLock Enclave

[Sascha Hauer <s.hauer@pengutronix.de>]

On Mon, Jul 22, 2024 at 10:21:39AM +0530, Pankaj Gupta wrote:
> NXP hardware IP(s) for secure-enclaves like Edgelock Enclave(ELE),
> are embedded in the SoC to support the features like HSM, SHE & V2X,
> using message based communication interface.
> 
> The secure enclave FW communicates on a dedicated messaging unit(MU)
> based interface(s) with application core, where kernel is running.
> It exists on specific i.MX processors. e.g. i.MX8ULP, i.MX93.
> 
> This patch adds the driver for communication interface to secure-enclave,
> for exchanging messages with NXP secure enclave HW IP(s) like EdgeLock
> Enclave (ELE) from Kernel-space, used by kernel management layers like
> - DM-Crypt.
> 
> Signed-off-by: Pankaj Gupta <pankaj.gupta@nxp.com>
> ---
>  drivers/firmware/imx/Kconfig        |  12 +
>  drivers/firmware/imx/Makefile       |   2 +
>  drivers/firmware/imx/ele_base_msg.c | 274 +++++++++++++++++++
>  drivers/firmware/imx/ele_base_msg.h |  95 +++++++
>  drivers/firmware/imx/ele_common.c   | 264 ++++++++++++++++++
>  drivers/firmware/imx/ele_common.h   |  44 +++
>  drivers/firmware/imx/se_ctrl.c      | 528 ++++++++++++++++++++++++++++++++++++
>  drivers/firmware/imx/se_ctrl.h      |  87 ++++++
>  include/linux/firmware/imx/se_api.h |  14 +
>  9 files changed, 1320 insertions(+)
> 
> diff --git a/drivers/firmware/imx/Kconfig b/drivers/firmware/imx/Kconfig
> index 183613f82a11..0f6877a24f0b 100644
> --- a/drivers/firmware/imx/Kconfig
> +++ b/drivers/firmware/imx/Kconfig
> @@ -22,3 +22,15 @@ config IMX_SCU
>  
>  	  This driver manages the IPC interface between host CPU and the
>  	  SCU firmware running on M4.
> +
> +config IMX_SEC_ENCLAVE
> +	tristate "i.MX Embedded Secure Enclave - EdgeLock Enclave Firmware driver."
> +	depends on IMX_MBOX && ARCH_MXC && ARM64
> +	default m if ARCH_MXC
> +
> +	help
> +	  It is possible to use APIs exposed by the iMX Secure Enclave HW IP called:
> +	  - EdgeLock Enclave Firmware (for i.MX8ULP, i.MX93),
> +	    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.
> diff --git a/drivers/firmware/imx/Makefile b/drivers/firmware/imx/Makefile
> index 8f9f04a513a8..aa9033e0e9e3 100644
> --- a/drivers/firmware/imx/Makefile
> +++ b/drivers/firmware/imx/Makefile
> @@ -1,3 +1,5 @@
>  # SPDX-License-Identifier: GPL-2.0
>  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_ctrl.o ele_common.o ele_base_msg.o
> +obj-${CONFIG_IMX_SEC_ENCLAVE}	+= sec_enclave.o
> diff --git a/drivers/firmware/imx/ele_base_msg.c b/drivers/firmware/imx/ele_base_msg.c
> new file mode 100644
> index 000000000000..7f16184a8b10
> --- /dev/null
> +++ b/drivers/firmware/imx/ele_base_msg.c
> @@ -0,0 +1,274 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright 2024 NXP
> + */
> +
> +#include <linux/types.h>
> +
> +#include <linux/completion.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/genalloc.h>
> +
> +#include "ele_base_msg.h"
> +#include "ele_common.h"
> +
> +int ele_get_info(struct device *dev, struct ele_dev_info *s_info)

I still think it's a bad idea to use some arbitrary struct device * as
context pointer here. Users will be confused which device is expected
here and bad things happen in case it's the wrong one.

You should rather implement some ele_get() function which returns some
pointer to be used as a context pointer here.

> +int ele_service_swap(struct device *dev,
> +		     phys_addr_t addr,
> +		     u32 addr_size, u16 flag)
> +{
> +	struct se_if_priv *priv = dev_get_drvdata(dev);
> +	struct se_api_msg *tx_msg __free(kfree) = NULL;
> +	struct se_api_msg *rx_msg __free(kfree) = NULL;
> +	int ret = 0;
> +
> +	if (!priv) {
> +		ret = -EINVAL;
> +		goto exit;
> +	}
> +
> +	tx_msg = kzalloc(ELE_SERVICE_SWAP_REQ_MSG_SZ, GFP_KERNEL);
> +	if (!tx_msg) {
> +		ret = -ENOMEM;
> +		goto exit;
> +	}
> +
> +	rx_msg = kzalloc(ELE_SERVICE_SWAP_RSP_MSG_SZ, GFP_KERNEL);
> +	if (!rx_msg) {
> +		ret = -ENOMEM;
> +		goto exit;
> +	}
> +	priv->rx_msg_sz = ELE_SERVICE_SWAP_RSP_MSG_SZ;
> +
> +	ret = se_fill_cmd_msg_hdr(priv,
> +				      (struct se_msg_hdr *)&tx_msg->header,
> +				      ELE_SERVICE_SWAP_REQ,
> +				      ELE_SERVICE_SWAP_REQ_MSG_SZ, true);
> +	if (ret)
> +		goto exit;
> +
> +	tx_msg->data[0] = flag;
> +	tx_msg->data[1] = addr_size;
> +	tx_msg->data[2] = ELE_NONE_VAL;
> +	tx_msg->data[3] = lower_32_bits(addr);

addr could be a 64bit address. Either handle this properly or return an
error when addr doesn't fit into 32bit.

> +int ele_fw_authenticate(struct device *dev, phys_addr_t addr)
> +{
> +	struct se_if_priv *priv = dev_get_drvdata(dev);
> +	struct se_api_msg *tx_msg __free(kfree) = NULL;
> +	struct se_api_msg *rx_msg __free(kfree) = NULL;
> +	int ret = 0;
> +
> +	if (!priv) {
> +		ret = -EINVAL;
> +		goto exit;
> +	}
> +
> +	tx_msg = kzalloc(ELE_FW_AUTH_REQ_SZ, GFP_KERNEL);
> +	if (!tx_msg) {
> +		ret = -ENOMEM;
> +		goto exit;
> +	}
> +
> +	rx_msg = kzalloc(ELE_FW_AUTH_RSP_MSG_SZ, GFP_KERNEL);
> +	if (!rx_msg) {
> +		ret = -ENOMEM;
> +		goto exit;
> +	}
> +	priv->rx_msg_sz = ELE_FW_AUTH_RSP_MSG_SZ;
> +
> +	ret = se_fill_cmd_msg_hdr(priv,
> +				  (struct se_msg_hdr *)&tx_msg->header,
> +				  ELE_FW_AUTH_REQ,
> +				  ELE_FW_AUTH_REQ_SZ,
> +				  true);
> +	if (ret)
> +		goto exit;
> +
> +	tx_msg->data[1] = upper_32_bits(addr);
> +	tx_msg->data[0] = lower_32_bits(addr);
> +	tx_msg->data[2] = addr;

Same here.

Sascha

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