Re: [PATCH 2/4] firmware: arm_ffa: Register core as a platform driver

[Yeoreum Yun <yeoreum.yun@arm.com>]

LGTM.

Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>

On Fri, May 08, 2026 at 06:54:16PM +0100, Sudeep Holla wrote:
> Move the FF-A core bring-up and teardown paths into platform driver
> probe and remove callbacks, and register a synthetic arm-ffa platform
> device to bind the driver.
> 
> This makes the FF-A core lifetime follow the driver model while keeping
> the device creation internal to the FF-A core. Use normal platform driver
> registration so the probe path has standard driver-core semantics.
> 
> The synthetic platform device is a temporary bridge until ACPI and
> devicetree describe the FF-A core device or object. Once those firmware
> description paths are defined, the internal platform device creation can
> be dropped and the driver can bind to the firmware-described device
> directly.
> 
> Since the transport selection now happens from the platform probe path,
> drop the __init annotation from ffa_transport_init().
> 
> Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
> ---
>  drivers/firmware/arm_ffa/common.h |  4 +--
>  drivers/firmware/arm_ffa/driver.c | 53 ++++++++++++++++++++++++++++++++++-----
>  drivers/firmware/arm_ffa/smccc.c  |  2 +-
>  3 files changed, 50 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/firmware/arm_ffa/common.h b/drivers/firmware/arm_ffa/common.h
> index 9c6425a81d0d..5cdf4bd222c6 100644
> --- a/drivers/firmware/arm_ffa/common.h
> +++ b/drivers/firmware/arm_ffa/common.h
> @@ -18,9 +18,9 @@ bool ffa_device_is_valid(struct ffa_device *ffa_dev);
>  void ffa_device_match_uuid(struct ffa_device *ffa_dev, const uuid_t *uuid);
>  
>  #ifdef CONFIG_ARM_FFA_SMCCC
> -int __init ffa_transport_init(ffa_fn **invoke_ffa_fn);
> +int ffa_transport_init(ffa_fn **invoke_ffa_fn);
>  #else
> -static inline int __init ffa_transport_init(ffa_fn **invoke_ffa_fn)
> +static inline int ffa_transport_init(ffa_fn **invoke_ffa_fn)
>  {
>  	return -EOPNOTSUPP;
>  }
> diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
> index 6efb85787e6e..97ecdb5dac09 100644
> --- a/drivers/firmware/arm_ffa/driver.c
> +++ b/drivers/firmware/arm_ffa/driver.c
> @@ -36,6 +36,7 @@
>  #include <linux/mm.h>
>  #include <linux/mutex.h>
>  #include <linux/of_irq.h>
> +#include <linux/platform_device.h>
>  #include <linux/scatterlist.h>
>  #include <linux/slab.h>
>  #include <linux/smp.h>
> @@ -46,6 +47,7 @@
>  
>  #define FFA_DRIVER_VERSION	FFA_VERSION_1_2
>  #define FFA_MIN_VERSION		FFA_VERSION_1_0
> +#define FFA_PLATFORM_NAME	"arm-ffa"
>  
>  #define SENDER_ID_MASK		GENMASK(31, 16)
>  #define RECEIVER_ID_MASK	GENMASK(15, 0)
> @@ -114,6 +116,7 @@ struct ffa_drv_info {
>  };
>  
>  static struct ffa_drv_info *drv_info;
> +static struct platform_device *ffa_pdev;
>  
>  /*
>   * The driver must be able to support all the versions from the earliest
> @@ -2029,7 +2032,7 @@ static void ffa_notifications_setup(void)
>  	ffa_notifications_cleanup();
>  }
>  
> -static int __init ffa_init(void)
> +static int ffa_probe(struct platform_device *pdev)
>  {
>  	int ret;
>  	u32 buf_sz;
> @@ -2042,6 +2045,7 @@ static int __init ffa_init(void)
>  	drv_info = kzalloc_obj(*drv_info);
>  	if (!drv_info)
>  		return -ENOMEM;
> +	platform_set_drvdata(pdev, drv_info);
>  
>  	ret = ffa_version_check(&drv_info->version);
>  	if (ret)
> @@ -2103,19 +2107,56 @@ static int __init ffa_init(void)
>  		free_pages_exact(drv_info->tx_buffer, rxtx_bufsz);
>  	free_pages_exact(drv_info->rx_buffer, rxtx_bufsz);
>  free_drv_info:
> +	platform_set_drvdata(pdev, NULL);
>  	kfree(drv_info);
> +	drv_info = NULL;
>  	return ret;
>  }
> -module_init(ffa_init);
>  
> -static void __exit ffa_exit(void)
> +static void ffa_remove(struct platform_device *pdev)
>  {
> +	struct ffa_drv_info *info = platform_get_drvdata(pdev);
> +
>  	ffa_notifications_cleanup();
>  	ffa_partitions_cleanup();
>  	ffa_rxtx_unmap();
> -	free_pages_exact(drv_info->tx_buffer, drv_info->rxtx_bufsz);
> -	free_pages_exact(drv_info->rx_buffer, drv_info->rxtx_bufsz);
> -	kfree(drv_info);
> +	free_pages_exact(info->tx_buffer, info->rxtx_bufsz);
> +	free_pages_exact(info->rx_buffer, info->rxtx_bufsz);
> +	kfree(info);
> +	platform_set_drvdata(pdev, NULL);
> +	drv_info = NULL;
> +}
> +
> +static struct platform_driver ffa_driver = {
> +	.probe = ffa_probe,
> +	.remove = ffa_remove,
> +	.driver = {
> +		.name = FFA_PLATFORM_NAME,
> +	},
> +};
> +
> +static int __init ffa_init(void)
> +{
> +	int ret;
> +
> +	ffa_pdev = platform_device_register_simple(FFA_PLATFORM_NAME,
> +						   PLATFORM_DEVID_NONE,
> +						   NULL, 0);
> +	if (IS_ERR(ffa_pdev))
> +		return PTR_ERR(ffa_pdev);
> +
> +	ret = platform_driver_register(&ffa_driver);
> +	if (ret)
> +		platform_device_unregister(ffa_pdev);
> +
> +	return ret;
> +}
> +module_init(ffa_init);
> +
> +static void __exit ffa_exit(void)
> +{
> +	platform_device_unregister(ffa_pdev);
> +	platform_driver_unregister(&ffa_driver);
>  }
>  module_exit(ffa_exit);
>  
> diff --git a/drivers/firmware/arm_ffa/smccc.c b/drivers/firmware/arm_ffa/smccc.c
> index 4d85bfff0a4e..e6125dd9f58f 100644
> --- a/drivers/firmware/arm_ffa/smccc.c
> +++ b/drivers/firmware/arm_ffa/smccc.c
> @@ -17,7 +17,7 @@ static void __arm_ffa_fn_hvc(ffa_value_t args, ffa_value_t *res)
>  	arm_smccc_1_2_hvc(&args, res);
>  }
>  
> -int __init ffa_transport_init(ffa_fn **invoke_ffa_fn)
> +int ffa_transport_init(ffa_fn **invoke_ffa_fn)
>  {
>  	enum arm_smccc_conduit conduit;
>  
> 
> -- 
> 2.43.0
> 

-- 
Sincerely,
Yeoreum Yun