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SubjectRe: [RFC PATCH 1/2] optee: model OP-TEE as a platform device/driver
Hi Ard and Arnd,

On Thu, Dec 27, 2018 at 8:01 PM Ard Biesheuvel
<ard.biesheuvel@linaro.org> wrote:
>
> To simplify adding ACPI support to the OP-TEE driver, model it as
> a platform driver. This will permit us to use the generic device
> property layer for parsing additional properties, regardless of
> whether DT or ACPI is being used.
>
> Note that this change will result in the OP-TEE driver to be loaded
> automatically on systems that advertise the presence of OP-TEE via
> the device tree.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> drivers/tee/optee/core.c | 86 ++++++++------------
> 1 file changed, 32 insertions(+), 54 deletions(-)

In the earlier postings of the TEE subsystem (v8) the OP-TEE device
was based on a platform device. Arnd didn't like this back then so it
was dropped. The situation has changed a bit now. A platform device
will make it easier to add ACPI support. Arnd, what do you think?

Thanks,
Jens

>
> diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
> index e1aafe842d66..61ea65cfaedd 100644
> --- a/drivers/tee/optee/core.c
> +++ b/drivers/tee/optee/core.c
> @@ -529,13 +529,13 @@ static void optee_smccc_hvc(unsigned long a0, unsigned long a1,
> arm_smccc_hvc(a0, a1, a2, a3, a4, a5, a6, a7, res);
> }
>
> -static optee_invoke_fn *get_invoke_func(struct device_node *np)
> +static optee_invoke_fn *get_invoke_func(struct device *dev)
> {
> const char *method;
>
> - pr_info("probing for conduit method from DT.\n");
> + pr_info("probing for conduit method.\n");
>
> - if (of_property_read_string(np, "method", &method)) {
> + if (device_property_read_string(dev, "method", &method)) {
> pr_warn("missing \"method\" property\n");
> return ERR_PTR(-ENXIO);
> }
> @@ -549,7 +549,7 @@ static optee_invoke_fn *get_invoke_func(struct device_node *np)
> return ERR_PTR(-EINVAL);
> }
>
> -static struct optee *optee_probe(struct device_node *np)
> +static int optee_probe(struct platform_device *pdev)
> {
> optee_invoke_fn *invoke_fn;
> struct tee_shm_pool *pool;
> @@ -559,25 +559,25 @@ static struct optee *optee_probe(struct device_node *np)
> u32 sec_caps;
> int rc;
>
> - invoke_fn = get_invoke_func(np);
> + invoke_fn = get_invoke_func(&pdev->dev);
> if (IS_ERR(invoke_fn))
> - return (void *)invoke_fn;
> + return PTR_ERR(invoke_fn);
>
> if (!optee_msg_api_uid_is_optee_api(invoke_fn)) {
> pr_warn("api uid mismatch\n");
> - return ERR_PTR(-EINVAL);
> + return -EINVAL;
> }
>
> optee_msg_get_os_revision(invoke_fn);
>
> if (!optee_msg_api_revision_is_compatible(invoke_fn)) {
> pr_warn("api revision mismatch\n");
> - return ERR_PTR(-EINVAL);
> + return -EINVAL;
> }
>
> if (!optee_msg_exchange_capabilities(invoke_fn, &sec_caps)) {
> pr_warn("capabilities mismatch\n");
> - return ERR_PTR(-EINVAL);
> + return -EINVAL;
> }
>
> /*
> @@ -585,11 +585,11 @@ static struct optee *optee_probe(struct device_node *np)
> * doesn't have any reserved memory we can use we can't continue.
> */
> if (!(sec_caps & OPTEE_SMC_SEC_CAP_HAVE_RESERVED_SHM))
> - return ERR_PTR(-EINVAL);
> + return -EINVAL;
>
> pool = optee_config_shm_memremap(invoke_fn, &memremaped_shm, sec_caps);
> if (IS_ERR(pool))
> - return (void *)pool;
> + return PTR_ERR(pool);
>
> optee = kzalloc(sizeof(*optee), GFP_KERNEL);
> if (!optee) {
> @@ -600,6 +600,8 @@ static struct optee *optee_probe(struct device_node *np)
> optee->invoke_fn = invoke_fn;
> optee->sec_caps = sec_caps;
>
> + platform_set_drvdata(pdev, optee);
> +
> teedev = tee_device_alloc(&optee_desc, NULL, pool, optee);
> if (IS_ERR(teedev)) {
> rc = PTR_ERR(teedev);
> @@ -632,7 +634,7 @@ static struct optee *optee_probe(struct device_node *np)
> optee_enable_shm_cache(optee);
>
> pr_info("initialized driver\n");
> - return optee;
> + return 0;
> err:
> if (optee) {
> /*
> @@ -648,11 +650,13 @@ static struct optee *optee_probe(struct device_node *np)
> tee_shm_pool_free(pool);
> if (memremaped_shm)
> memunmap(memremaped_shm);
> - return ERR_PTR(rc);
> + return rc;
> }
>
> -static void optee_remove(struct optee *optee)
> +static int optee_remove(struct platform_device *pdev)
> {
> + struct optee *optee = platform_get_drvdata(pdev);
> +
> /*
> * Ask OP-TEE to free all cached shared memory objects to decrease
> * reference counters and also avoid wild pointers in secure world
> @@ -675,51 +679,25 @@ static void optee_remove(struct optee *optee)
> mutex_destroy(&optee->call_queue.mutex);
>
> kfree(optee);
> +
> + return 0;
> }
>
> -static const struct of_device_id optee_match[] = {
> +static const struct of_device_id optee_dt_match[] = {
> { .compatible = "linaro,optee-tz" },
> {},
> };
> -
> -static struct optee *optee_svc;
> -
> -static int __init optee_driver_init(void)
> -{
> - struct device_node *fw_np;
> - struct device_node *np;
> - struct optee *optee;
> -
> - /* Node is supposed to be below /firmware */
> - fw_np = of_find_node_by_name(NULL, "firmware");
> - if (!fw_np)
> - return -ENODEV;
> -
> - np = of_find_matching_node(fw_np, optee_match);
> - if (!np)
> - return -ENODEV;
> -
> - optee = optee_probe(np);
> - of_node_put(np);
> -
> - if (IS_ERR(optee))
> - return PTR_ERR(optee);
> -
> - optee_svc = optee;
> -
> - return 0;
> -}
> -module_init(optee_driver_init);
> -
> -static void __exit optee_driver_exit(void)
> -{
> - struct optee *optee = optee_svc;
> -
> - optee_svc = NULL;
> - if (optee)
> - optee_remove(optee);
> -}
> -module_exit(optee_driver_exit);
> +MODULE_DEVICE_TABLE(of, optee_dt_match);
> +
> +static struct platform_driver optee_driver = {
> + .probe = optee_probe,
> + .remove = optee_remove,
> + .driver = {
> + .name = "optee",
> + .of_match_table = optee_dt_match,
> + },
> +};
> +module_platform_driver(optee_driver);
>
> MODULE_AUTHOR("Linaro");
> MODULE_DESCRIPTION("OP-TEE driver");
> --
> 2.19.2
>

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