[PATCH 0/4] firmware: arm_ffa: Move core init to platform driver probe

[PATCH 0/4] firmware: arm_ffa: Move core init to platform driver probe

[Sudeep Holla]

This series moves the Arm FF-A core initialisation into the driver model by
converting the core bring-up path to a platform driver probe/remove flow.

The first patch reverts the earlier rootfs_initcall change. That initcall
ordering workaround is not a proper solution and potentially conflicts with
pKVM FF-A proxy requirement.

The FF-A core is then registered as a platform driver. For now, the driver
creates a synthetic arm-ffa platform device internally to bind the driver.
This is intended as a temporary bridge until ACPI and devicetree describe
the FF-A core device or object directly, at which point the internal device
creation can be dropped.

The series also makes the synthetic core device the parent of enumerated
FF-A partition devices, keeping the FF-A device hierarchy anchored under the
core transport device.

Finally, when protected KVM is enabled, FF-A probing is deferred until pKVM
has completed initialisation. The kernel pKVM FF-A proxy must perform its
own FF-A version negotiation and setup before the normal FF-A driver starts
using the transport, so the platform driver probe path now allows the driver
core to retry once that dependency is ready.

Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
---
Sudeep Holla (3):
      firmware: arm_ffa: Register core as a platform driver
      firmware: arm_ffa: Set the core device as FF-A device parent
      firmware: arm_ffa: Defer probe until pKVM is initialized

Yeoreum Yun (1):
      Revert "firmware: arm_ffa: Change initcall level of ffa_init() to rootfs_initcall"

 drivers/firmware/arm_ffa/bus.c    |  3 +-
 drivers/firmware/arm_ffa/common.h |  4 +--
 drivers/firmware/arm_ffa/driver.c | 64 ++++++++++++++++++++++++++++++++++-----
 drivers/firmware/arm_ffa/smccc.c  |  2 +-
 include/linux/arm_ffa.h           |  4 +--
 5 files changed, 63 insertions(+), 14 deletions(-)
---
base-commit: 917719c412c48687d4a176965d1fa35320ec457c
change-id: 20260508-b4-ffa_plat_dev-39b98bb79ae9


-- 
Regards,
Sudeep

[PATCH 1/4] Revert "firmware: arm_ffa: Change initcall level of ffa_init() to rootfs_initcall"

[Sudeep Holla]

From: Yeoreum Yun <yeoreum.yun@arm.com>

This reverts commit 0e0546eabcd6c19765a8dbf5b5db3723e7b0ea75, which was
added to address ordering issues with the IMA LSM initialisation where
the TPM would not be fully ready by the time IMA wanted it. This has
been resolved within IMA by retrying setup during late_initcall_sync if
the TPM is not available at first.

Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
---
 drivers/firmware/arm_ffa/driver.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index eb2782848283..6efb85787e6e 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -2106,7 +2106,7 @@ static int __init ffa_init(void)
 	kfree(drv_info);
 	return ret;
 }
-rootfs_initcall(ffa_init);
+module_init(ffa_init);
 
 static void __exit ffa_exit(void)
 {

-- 
2.43.0

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

[Sudeep Holla]

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

[PATCH 3/4] firmware: arm_ffa: Set the core device as FF-A device parent

[Sudeep Holla]

Pass a parent device into ffa_device_register() and use the synthetic
arm-ffa platform device as the parent for each registered FF-A device.

This keeps the enumerated FF-A partition devices anchored below the FF-A
core device in the driver model, matching the platform-driver conversion
of the core transport.

Suggested-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
---
 drivers/firmware/arm_ffa/bus.c    | 3 ++-
 drivers/firmware/arm_ffa/driver.c | 5 +++--
 include/linux/arm_ffa.h           | 4 ++--
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/firmware/arm_ffa/bus.c b/drivers/firmware/arm_ffa/bus.c
index 9576862d89c4..e05fe0b6049c 100644
--- a/drivers/firmware/arm_ffa/bus.c
+++ b/drivers/firmware/arm_ffa/bus.c
@@ -190,7 +190,7 @@ bool ffa_device_is_valid(struct ffa_device *ffa_dev)
 
 struct ffa_device *
 ffa_device_register(const struct ffa_partition_info *part_info,
-		    const struct ffa_ops *ops)
+		    const struct ffa_ops *ops, struct device *parent)
 {
 	int id, ret;
 	struct device *dev;
@@ -210,6 +210,7 @@ ffa_device_register(const struct ffa_partition_info *part_info,
 	}
 
 	dev = &ffa_dev->dev;
+	dev->parent = parent;
 	dev->bus = &ffa_bus_type;
 	dev->release = ffa_release_device;
 	dev->dma_mask = &dev->coherent_dma_mask;
diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index 97ecdb5dac09..e9d7dc71c06d 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -1688,7 +1688,7 @@ static int ffa_setup_host_partition(int vm_id)
 	int ret;
 
 	buf.id = vm_id;
-	ffa_dev = ffa_device_register(&buf, &ffa_drv_ops);
+	ffa_dev = ffa_device_register(&buf, &ffa_drv_ops, &ffa_pdev->dev);
 	if (!ffa_dev) {
 		pr_err("%s: failed to register host partition ID 0x%x\n",
 		       __func__, vm_id);
@@ -1758,7 +1758,8 @@ static int ffa_setup_partitions(void)
 		 * provides UUID here for each partition as part of the
 		 * discovery API and the same is passed.
 		 */
-		ffa_dev = ffa_device_register(tpbuf, &ffa_drv_ops);
+		ffa_dev = ffa_device_register(tpbuf, &ffa_drv_ops,
+					      &ffa_pdev->dev);
 		if (!ffa_dev) {
 			pr_err("%s: failed to register partition ID 0x%x\n",
 			       __func__, tpbuf->id);
diff --git a/include/linux/arm_ffa.h b/include/linux/arm_ffa.h
index 81e603839c4a..17eca3dfc59e 100644
--- a/include/linux/arm_ffa.h
+++ b/include/linux/arm_ffa.h
@@ -173,7 +173,7 @@ struct ffa_partition_info;
 #if IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)
 struct ffa_device *
 ffa_device_register(const struct ffa_partition_info *part_info,
-		    const struct ffa_ops *ops);
+		    const struct ffa_ops *ops, struct device *parent);
 void ffa_device_unregister(struct ffa_device *ffa_dev);
 int ffa_driver_register(struct ffa_driver *driver, struct module *owner,
 			const char *mod_name);
@@ -184,7 +184,7 @@ bool ffa_device_is_valid(struct ffa_device *ffa_dev);
 #else
 static inline struct ffa_device *
 ffa_device_register(const struct ffa_partition_info *part_info,
-		    const struct ffa_ops *ops)
+		    const struct ffa_ops *ops, struct device *parent)
 {
 	return NULL;
 }

-- 
2.43.0

[PATCH 4/4] firmware: arm_ffa: Defer probe until pKVM is initialized

[Sudeep Holla]

When protected KVM is enabled, the kernel includes a pKVM FF-A proxy
that sits in front of the normal FF-A driver. The proxy has to perform
its own FF-A version negotiation and setup first, so that it can mediate
subsequent FF-A traffic correctly.

Defer FF-A core probing until pKVM has completed initialization. This
keeps the normal driver from negotiating the FF-A version or performing
other transport setup before the pKVM proxy is ready, and lets the
driver model retry probing once the protected KVM state required by the
FF-A transport is available.

Suggested-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
---
 drivers/firmware/arm_ffa/driver.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index e9d7dc71c06d..1fba064c2aba 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -43,6 +43,8 @@
 #include <linux/uuid.h>
 #include <linux/xarray.h>
 
+#include <asm/virt.h>
+
 #include "common.h"
 
 #define FFA_DRIVER_VERSION	FFA_VERSION_1_2
@@ -2039,6 +2041,10 @@ static int ffa_probe(struct platform_device *pdev)
 	u32 buf_sz;
 	size_t rxtx_bufsz = SZ_4K;
 
+	if (IS_BUILTIN(CONFIG_ARM_FFA_TRANSPORT) &&
+	    is_protected_kvm_enabled() && !is_pkvm_initialized())
+		return -EPROBE_DEFER;
+
 	ret = ffa_transport_init(&invoke_ffa_fn);
 	if (ret)
 		return ret;

-- 
2.43.0

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

[Yeoreum Yun]

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

Re: [PATCH 3/4] firmware: arm_ffa: Set the core device as FF-A device parent

[Yeoreum Yun]

LGTM.

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

> Pass a parent device into ffa_device_register() and use the synthetic
> arm-ffa platform device as the parent for each registered FF-A device.
> 
> This keeps the enumerated FF-A partition devices anchored below the FF-A
> core device in the driver model, matching the platform-driver conversion
> of the core transport.
> 
> Suggested-by: Yeoreum Yun <yeoreum.yun@arm.com>
> Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
> ---
>  drivers/firmware/arm_ffa/bus.c    | 3 ++-
>  drivers/firmware/arm_ffa/driver.c | 5 +++--
>  include/linux/arm_ffa.h           | 4 ++--
>  3 files changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/firmware/arm_ffa/bus.c b/drivers/firmware/arm_ffa/bus.c
> index 9576862d89c4..e05fe0b6049c 100644
> --- a/drivers/firmware/arm_ffa/bus.c
> +++ b/drivers/firmware/arm_ffa/bus.c
> @@ -190,7 +190,7 @@ bool ffa_device_is_valid(struct ffa_device *ffa_dev)
>  
>  struct ffa_device *
>  ffa_device_register(const struct ffa_partition_info *part_info,
> -		    const struct ffa_ops *ops)
> +		    const struct ffa_ops *ops, struct device *parent)
>  {
>  	int id, ret;
>  	struct device *dev;
> @@ -210,6 +210,7 @@ ffa_device_register(const struct ffa_partition_info *part_info,
>  	}
>  
>  	dev = &ffa_dev->dev;
> +	dev->parent = parent;
>  	dev->bus = &ffa_bus_type;
>  	dev->release = ffa_release_device;
>  	dev->dma_mask = &dev->coherent_dma_mask;
> diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
> index 97ecdb5dac09..e9d7dc71c06d 100644
> --- a/drivers/firmware/arm_ffa/driver.c
> +++ b/drivers/firmware/arm_ffa/driver.c
> @@ -1688,7 +1688,7 @@ static int ffa_setup_host_partition(int vm_id)
>  	int ret;
>  
>  	buf.id = vm_id;
> -	ffa_dev = ffa_device_register(&buf, &ffa_drv_ops);
> +	ffa_dev = ffa_device_register(&buf, &ffa_drv_ops, &ffa_pdev->dev);
>  	if (!ffa_dev) {
>  		pr_err("%s: failed to register host partition ID 0x%x\n",
>  		       __func__, vm_id);
> @@ -1758,7 +1758,8 @@ static int ffa_setup_partitions(void)
>  		 * provides UUID here for each partition as part of the
>  		 * discovery API and the same is passed.
>  		 */
> -		ffa_dev = ffa_device_register(tpbuf, &ffa_drv_ops);
> +		ffa_dev = ffa_device_register(tpbuf, &ffa_drv_ops,
> +					      &ffa_pdev->dev);
>  		if (!ffa_dev) {
>  			pr_err("%s: failed to register partition ID 0x%x\n",
>  			       __func__, tpbuf->id);
> diff --git a/include/linux/arm_ffa.h b/include/linux/arm_ffa.h
> index 81e603839c4a..17eca3dfc59e 100644
> --- a/include/linux/arm_ffa.h
> +++ b/include/linux/arm_ffa.h
> @@ -173,7 +173,7 @@ struct ffa_partition_info;
>  #if IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)
>  struct ffa_device *
>  ffa_device_register(const struct ffa_partition_info *part_info,
> -		    const struct ffa_ops *ops);
> +		    const struct ffa_ops *ops, struct device *parent);
>  void ffa_device_unregister(struct ffa_device *ffa_dev);
>  int ffa_driver_register(struct ffa_driver *driver, struct module *owner,
>  			const char *mod_name);
> @@ -184,7 +184,7 @@ bool ffa_device_is_valid(struct ffa_device *ffa_dev);
>  #else
>  static inline struct ffa_device *
>  ffa_device_register(const struct ffa_partition_info *part_info,
> -		    const struct ffa_ops *ops)
> +		    const struct ffa_ops *ops, struct device *parent)
>  {
>  	return NULL;
>  }
> 
> -- 
> 2.43.0
> 

-- 
Sincerely,
Yeoreum Yun

Re: [PATCH 4/4] firmware: arm_ffa: Defer probe until pKVM is initialized

[Yeoreum Yun]

Look good to me.

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

> When protected KVM is enabled, the kernel includes a pKVM FF-A proxy
> that sits in front of the normal FF-A driver. The proxy has to perform
> its own FF-A version negotiation and setup first, so that it can mediate
> subsequent FF-A traffic correctly.
> 
> Defer FF-A core probing until pKVM has completed initialization. This
> keeps the normal driver from negotiating the FF-A version or performing
> other transport setup before the pKVM proxy is ready, and lets the
> driver model retry probing once the protected KVM state required by the
> FF-A transport is available.
> 
> Suggested-by: Yeoreum Yun <yeoreum.yun@arm.com>
> Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
> ---
>  drivers/firmware/arm_ffa/driver.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
> index e9d7dc71c06d..1fba064c2aba 100644
> --- a/drivers/firmware/arm_ffa/driver.c
> +++ b/drivers/firmware/arm_ffa/driver.c
> @@ -43,6 +43,8 @@
>  #include <linux/uuid.h>
>  #include <linux/xarray.h>
>  
> +#include <asm/virt.h>
> +
>  #include "common.h"
>  
>  #define FFA_DRIVER_VERSION	FFA_VERSION_1_2
> @@ -2039,6 +2041,10 @@ static int ffa_probe(struct platform_device *pdev)
>  	u32 buf_sz;
>  	size_t rxtx_bufsz = SZ_4K;
>  
> +	if (IS_BUILTIN(CONFIG_ARM_FFA_TRANSPORT) &&
> +	    is_protected_kvm_enabled() && !is_pkvm_initialized())
> +		return -EPROBE_DEFER;
> +
>  	ret = ffa_transport_init(&invoke_ffa_fn);
>  	if (ret)
>  		return ret;
> 
> -- 
> 2.43.0
> 

-- 
Sincerely,
Yeoreum Yun