Re: [PATCH v4 05/11] firmware: qcom: scm: add support for object invocation

Sumit Garg
2025-05-14T09:37:22Z

Hi Amir,

On Mon, Apr 28, 2025 at 11:06:26PM -0700, Amirreza Zarrabi wrote:
> Qualcomm TEE (QTEE) hosts Trusted Applications (TAs) and services in
> the secure world, accessed via objects. A QTEE client can invoke these
> objects to request services. Similarly, QTEE can request services from
> the nonsecure world using objects exported to the secure world.
>
> Add low-level primitives to facilitate the invocation of objects hosted
> in QTEE, as well as those hosted in the nonsecure world.
>
> If support for object invocation is available, the qcom_scm allocates
> a dedicated child platform device. The driver for this device communicates
> with QTEE using low-level primitives.
>
> Signed-off-by: Amirreza Zarrabi <amirreza.zarrabi@oss.qualcomm.com>
> ---
> drivers/firmware/qcom/qcom_scm.c | 128 +++++++++++++++++++++++++++++++++
> drivers/firmware/qcom/qcom_scm.h | 7 ++
> include/linux/firmware/qcom/qcom_scm.h | 27 +++++++
> 3 files changed, 162 insertions(+)
>
> diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
> index fc4d67e4c4a6..bff1b0d3306e 100644
> --- a/drivers/firmware/qcom/qcom_scm.c
> +++ b/drivers/firmware/qcom/qcom_scm.c
> @@ -2084,6 +2084,124 @@ static int qcom_scm_qseecom_init(struct qcom_scm *scm)
>
> #endif /* CONFIG_QCOM_QSEECOM */
>
> +#ifdef CONFIG_QCOMTEE
> +
> +/**
> + * qcom_scm_qtee_invoke_smc() - Invoke a QTEE object.
> + * @inbuf: start address of memory area used for inbound buffer.
> + * @inbuf_size: size of the memory area used for inbound buffer.
> + * @outbuf: start address of memory area used for outbound buffer.
> + * @outbuf_size: size of the memory area used for outbound buffer.
> + * @result: result of QTEE object invocation.
> + * @response_type: response type returned by QTEE.
> + *
> + * @response_type determines how the contents of @inbuf and @outbuf
> + * should be processed.
> + *
> + * Return: On success, return 0 or <0 on failure.
> + */
> +int qcom_scm_qtee_invoke_smc(phys_addr_t inbuf, size_t inbuf_size,
> + phys_addr_t outbuf, size_t outbuf_size,
> + u64 *result, u64 *response_type)
> +{
> + struct qcom_scm_desc desc = {
> + .svc = QCOM_SCM_SVC_SMCINVOKE,
> + .cmd = QCOM_SCM_SMCINVOKE_INVOKE,
> + .owner = ARM_SMCCC_OWNER_TRUSTED_OS,
> + .args[0] = inbuf,
> + .args[1] = inbuf_size,
> + .args[2] = outbuf,
> + .args[3] = outbuf_size,
> + .arginfo = QCOM_SCM_ARGS(4, QCOM_SCM_RW, QCOM_SCM_VAL,
> + QCOM_SCM_RW, QCOM_SCM_VAL),
> + };
> + struct qcom_scm_res res;
> + int ret;
> +
> + ret = qcom_scm_call(__scm->dev, &desc, &res);
> + if (ret)
> + return ret;
> +
> + *response_type = res.result[0];
> + *result = res.result[1];
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(qcom_scm_qtee_invoke_smc);
> +
> +/**
> + * qcom_scm_qtee_callback_response() - Submit response for callback request.
> + * @buf: start address of memory area used for outbound buffer.
> + * @buf_size: size of the memory area used for outbound buffer.
> + * @result: Result of QTEE object invocation.
> + * @response_type: Response type returned by QTEE.
> + *
> + * @response_type determines how the contents of @buf should be processed.
> + *
> + * Return: On success, return 0 or <0 on failure.
> + */
> +int qcom_scm_qtee_callback_response(phys_addr_t buf, size_t buf_size,
> + u64 *result, u64 *response_type)
> +{
> + struct qcom_scm_desc desc = {
> + .svc = QCOM_SCM_SVC_SMCINVOKE,
> + .cmd = QCOM_SCM_SMCINVOKE_CB_RSP,
> + .owner = ARM_SMCCC_OWNER_TRUSTED_OS,
> + .args[0] = buf,
> + .args[1] = buf_size,
> + .arginfo = QCOM_SCM_ARGS(2, QCOM_SCM_RW, QCOM_SCM_VAL),
> + };
> + struct qcom_scm_res res;
> + int ret;
> +
> + ret = qcom_scm_call(__scm->dev, &desc, &res);
> + if (ret)
> + return ret;
> +
> + *response_type = res.result[0];
> + *result = res.result[1];
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(qcom_scm_qtee_callback_response);
> +
> +static void qcom_scm_qtee_free(void *data)
> +{
> + struct platform_device *qtee_dev = data;
> +
> + platform_device_unregister(qtee_dev);
> +}
> +
> +static int qcom_scm_qtee_init(struct qcom_scm *scm)
> +{
> + struct platform_device *qtee_dev;
> + int ret;
> +

I am still unable to get the QCOMTEE driver to work on db845c. As I can
see machine: "qcom,sdm845" is not supported for tzmem based on SHM
brigde here: drivers/firmware/qcom/qcom_tzmem.c +81. I am still seeing
following logs from userspace:

# /mnt/unittest -d
[test_print_diagnostics_info][31] test_get_client_env_object.
[test_supplicant_release][65] test_supplicant_worker killed.

I think you should first check here for SHM bridge support. If available
then only add a QTEE platform device.

-Sumit

> + /* Setup QTEE interface device. */
> + qtee_dev = platform_device_alloc("qcomtee", -1);
> + if (!qtee_dev)
> + return -ENOMEM;
> +
> + qtee_dev->dev.parent = scm->dev;
> +
> + ret = platform_device_add(qtee_dev);
> + if (ret) {
> + platform_device_put(qtee_dev);
> + return ret;
> + }
> +
> + return devm_add_action_or_reset(scm->dev, qcom_scm_qtee_free, qtee_dev);
> +}
> +
> +#else
> +
> +static int qcom_scm_qtee_init(struct qcom_scm *scm)
> +{
> + return 0;
> +}
> +
> +#endif /* CONFIG_QCOMTEE */
> +
> /**
> * qcom_scm_is_available() - Checks if SCM is available
> */
> @@ -2319,6 +2437,16 @@ static int qcom_scm_probe(struct platform_device *pdev)
> ret = qcom_scm_qseecom_init(scm);
> WARN(ret < 0, "failed to initialize qseecom: %d\n", ret);
>
> + /*
> + * Initialize the QTEE object interface.
> + *
> + * This only represents the availability for QTEE object invocation
> + * and callback support. On failure, ignore the result. Any subsystem
> + * depending on it may fail if it tries to access this interface.
> + */
> + ret = qcom_scm_qtee_init(scm);
> + WARN(ret < 0, "failed to initialize qcomtee: %d\n", ret);
> +
> return 0;
>
> err:
> diff --git a/drivers/firmware/qcom/qcom_scm.h b/drivers/firmware/qcom/qcom_scm.h
> index 097369d38b84..a25202e99f7c 100644
> --- a/drivers/firmware/qcom/qcom_scm.h
> +++ b/drivers/firmware/qcom/qcom_scm.h
> @@ -152,6 +152,13 @@ struct qcom_tzmem_pool *qcom_scm_get_tzmem_pool(void);
> #define QCOM_SCM_SVC_GPU 0x28
> #define QCOM_SCM_SVC_GPU_INIT_REGS 0x01
>
> +/* ARM_SMCCC_OWNER_TRUSTED_OS calls */
> +
> +#define QCOM_SCM_SVC_SMCINVOKE 0x06
> +#define QCOM_SCM_SMCINVOKE_INVOKE_LEGACY 0x00
> +#define QCOM_SCM_SMCINVOKE_CB_RSP 0x01
> +#define QCOM_SCM_SMCINVOKE_INVOKE 0x02
> +
> /* common error codes */
> #define QCOM_SCM_V2_EBUSY -12
> #define QCOM_SCM_ENOMEM -5
> diff --git a/include/linux/firmware/qcom/qcom_scm.h b/include/linux/firmware/qcom/qcom_scm.h
> index 983e1591bbba..bf5e64f6deba 100644
> --- a/include/linux/firmware/qcom/qcom_scm.h
> +++ b/include/linux/firmware/qcom/qcom_scm.h
> @@ -176,4 +176,31 @@ static inline int qcom_scm_qseecom_app_send(u32 app_id,
>
> #endif /* CONFIG_QCOM_QSEECOM */
>
> +#ifdef CONFIG_QCOMTEE
> +
> +int qcom_scm_qtee_invoke_smc(phys_addr_t inbuf, size_t inbuf_size,
> + phys_addr_t outbuf, size_t outbuf_size,
> + u64 *result, u64 *response_type);
> +int qcom_scm_qtee_callback_response(phys_addr_t buf, size_t buf_size,
> + u64 *result, u64 *response_type);
> +
> +#else /* CONFIG_QCOMTEE */
> +
> +static inline int qcom_scm_qtee_invoke_smc(phys_addr_t inbuf, size_t inbuf_size,
> + phys_addr_t outbuf,
> + size_t outbuf_size, u64 *result,
> + u64 *response_type)
> +{
> + return -EINVAL;
> +}
> +
> +static inline int qcom_scm_qtee_callback_response(phys_addr_t buf,
> + size_t buf_size, u64 *result,
> + u64 *response_type)
> +{
> + return -EINVAL;
> +}
> +
> +#endif /* CONFIG_QCOMTEE */
> +
> #endif
>
> --
> 2.34.1
>
>