diff mbox series

[1/2] firmware: arm_ffa: Move the FF-A v1.0 NULL UUID workaround to bus notifier

Message ID 20240510183811.3802285-1-sudeep.holla@arm.com (mailing list archive)
State New
Headers show
Series [1/2] firmware: arm_ffa: Move the FF-A v1.0 NULL UUID workaround to bus notifier | expand

Commit Message

Sudeep Holla May 10, 2024, 6:38 p.m. UTC 
Currently FF-A bus ffa_device_match() handles the workaround for the
FF-A v1.0 devices which are not populated with UUID to match. The FF-A
bus layer calls into FF-A driver and populates the device UUID if it
matches with the driver attempting to match.

But this forces to have both FF-A bus and core driver to be bundled into
a single module. However, keep it as a single module adds problems for
the FF-A driver registrations and their initcall levels.

In preparation to split the FF-A bus and the core driver into distinct
modules, we need to move the workaround away from the FF-A bus layer.
We can add it into the FF-A core driver as a bus notifier.

In order to do so, we need to always match any driver with the device if
the UUID is NULL and then during the driver binding phase, we can populate
the UUID if it matches with the driver UUID table using the bus notifiers.
We also need to add a check for NULL UUID before calling the device/driver
probe as devices with NULL UUID is possible since we match all for that
case.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 drivers/firmware/arm_ffa/driver.c | 33 ++++++++++++++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

--
2.43.2

Comments

Sebastian Ene May 14, 2024, 12:55 p.m. UTC | #1 
On Fri, May 10, 2024 at 07:38:10PM +0100, Sudeep Holla wrote:
> Currently FF-A bus ffa_device_match() handles the workaround for the
> FF-A v1.0 devices which are not populated with UUID to match. The FF-A
> bus layer calls into FF-A driver and populates the device UUID if it
> matches with the driver attempting to match.
> 
> But this forces to have both FF-A bus and core driver to be bundled into
> a single module. However, keep it as a single module adds problems for
> the FF-A driver registrations and their initcall levels.
> 
> In preparation to split the FF-A bus and the core driver into distinct
> modules, we need to move the workaround away from the FF-A bus layer.
> We can add it into the FF-A core driver as a bus notifier.
> 
> In order to do so, we need to always match any driver with the device if
> the UUID is NULL and then during the driver binding phase, we can populate
> the UUID if it matches with the driver UUID table using the bus notifiers.
> We also need to add a check for NULL UUID before calling the device/driver
> probe as devices with NULL UUID is possible since we match all for that
> case.
> 
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> ---
>  drivers/firmware/arm_ffa/driver.c | 33 ++++++++++++++++++++++++++++++-
>  1 file changed, 32 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
> index 9f89ee0aaa6b..159f2106a541 100644
> --- a/drivers/firmware/arm_ffa/driver.c
> +++ b/drivers/firmware/arm_ffa/driver.c
> @@ -1235,6 +1235,29 @@ void ffa_device_match_uuid(struct ffa_device *ffa_dev, const uuid_t *uuid)
>  	kfree(pbuf);
>  }

Hello Sudeep,

> 
> +static int
> +ffa_bus_notifier(struct notifier_block *nb, unsigned long action, void *data)
> +{
> +	struct device *dev = data;
> +	struct ffa_device *fdev = to_ffa_dev(dev);
> +
> +	if (action == BUS_NOTIFY_BIND_DRIVER) {
> +		struct ffa_driver *ffa_drv = to_ffa_driver(dev->driver);
> +		const struct ffa_device_id *id_table = ffa_drv->id_table;
> +
> +		if (uuid_is_null(&fdev->uuid))
> +			ffa_device_match_uuid(fdev, &id_table->uuid);
> +
> +		return NOTIFY_OK;
> +	}
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static struct notifier_block ffa_bus_nb = {
> +	.notifier_call = ffa_bus_notifier,
> +};
> +
>  static int ffa_setup_partitions(void)
>  {
>  	int count, idx, ret;
> @@ -1243,6 +1266,14 @@ static int ffa_setup_partitions(void)
>  	struct ffa_dev_part_info *info;
>  	struct ffa_partition_info *pbuf, *tpbuf;
> 
> +	if (drv_info->version == FFA_VERSION_1_0) {

Should we remove the version check inside the ffa_device_match_uuid
function as this function will only be called from the bus notifier ?

> +		ret = bus_register_notifier(&ffa_bus_type, &ffa_bus_nb);
> +		if (ret) {
> +			pr_err("Failed to register FF-A bus notifiers\n");
> +			return ret;
> +		}
> +	}
> +
>  	count = ffa_partition_probe(&uuid_null, &pbuf);
>  	if (count <= 0) {
>  		pr_info("%s: No partitions found, error %d\n", __func__, count);
> @@ -1254,7 +1285,7 @@ static int ffa_setup_partitions(void)
>  		import_uuid(&uuid, (u8 *)tpbuf->uuid);
> 
>  		/* Note that if the UUID will be uuid_null, that will require
> -		 * ffa_device_match() to find the UUID of this partition id
> +		 * ffa_bus_notifier() to find the UUID of this partition id
>  		 * with help of ffa_device_match_uuid(). FF-A v1.1 and above
>  		 * provides UUID here for each partition as part of the
>  		 * discovery API and the same is passed.
> --
> 2.43.2
> 

Also I wonder if we should have the change from patch 2 (the one which
removes the ffa_device_match_uuid call from ffa_device_match) inside
this. Wdyth ?


Thank you,
Sebastian
Sudeep Holla May 14, 2024, 2:45 p.m. UTC | #2 
On Tue, May 14, 2024 at 12:55:20PM +0000, Sebastian Ene wrote:
> On Fri, May 10, 2024 at 07:38:10PM +0100, Sudeep Holla wrote:
> > Currently FF-A bus ffa_device_match() handles the workaround for the
> > FF-A v1.0 devices which are not populated with UUID to match. The FF-A
> > bus layer calls into FF-A driver and populates the device UUID if it
> > matches with the driver attempting to match.
> > 
> > But this forces to have both FF-A bus and core driver to be bundled into
> > a single module. However, keep it as a single module adds problems for
> > the FF-A driver registrations and their initcall levels.
> > 
> > In preparation to split the FF-A bus and the core driver into distinct
> > modules, we need to move the workaround away from the FF-A bus layer.
> > We can add it into the FF-A core driver as a bus notifier.
> > 
> > In order to do so, we need to always match any driver with the device if
> > the UUID is NULL and then during the driver binding phase, we can populate
> > the UUID if it matches with the driver UUID table using the bus notifiers.
> > We also need to add a check for NULL UUID before calling the device/driver
> > probe as devices with NULL UUID is possible since we match all for that
> > case.
> > 
> > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> > ---
> >  drivers/firmware/arm_ffa/driver.c | 33 ++++++++++++++++++++++++++++++-
> >  1 file changed, 32 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
> > index 9f89ee0aaa6b..159f2106a541 100644
> > --- a/drivers/firmware/arm_ffa/driver.c
> > +++ b/drivers/firmware/arm_ffa/driver.c
> > @@ -1235,6 +1235,29 @@ void ffa_device_match_uuid(struct ffa_device *ffa_dev, const uuid_t *uuid)
> >  	kfree(pbuf);
> >  }
> 
> Hello Sudeep,
> 
> > 
> > +static int
> > +ffa_bus_notifier(struct notifier_block *nb, unsigned long action, void *data)
> > +{
> > +	struct device *dev = data;
> > +	struct ffa_device *fdev = to_ffa_dev(dev);
> > +
> > +	if (action == BUS_NOTIFY_BIND_DRIVER) {
> > +		struct ffa_driver *ffa_drv = to_ffa_driver(dev->driver);
> > +		const struct ffa_device_id *id_table = ffa_drv->id_table;
> > +
> > +		if (uuid_is_null(&fdev->uuid))
> > +			ffa_device_match_uuid(fdev, &id_table->uuid);
> > +
> > +		return NOTIFY_OK;
> > +	}
> > +
> > +	return NOTIFY_DONE;
> > +}
> > +
> > +static struct notifier_block ffa_bus_nb = {
> > +	.notifier_call = ffa_bus_notifier,
> > +};
> > +
> >  static int ffa_setup_partitions(void)
> >  {
> >  	int count, idx, ret;
> > @@ -1243,6 +1266,14 @@ static int ffa_setup_partitions(void)
> >  	struct ffa_dev_part_info *info;
> >  	struct ffa_partition_info *pbuf, *tpbuf;
> > 
> > +	if (drv_info->version == FFA_VERSION_1_0) {
> 
> Should we remove the version check inside the ffa_device_match_uuid
> function as this function will only be called from the bus notifier ?
>

Good catch, I didn't notice we already have the check there. I will drop
that version check inside ffa_device_match_uuid().

> > +		ret = bus_register_notifier(&ffa_bus_type, &ffa_bus_nb);
> > +		if (ret) {
> > +			pr_err("Failed to register FF-A bus notifiers\n");
> > +			return ret;
> > +		}
> > +	}
> > +
> >  	count = ffa_partition_probe(&uuid_null, &pbuf);
> >  	if (count <= 0) {
> >  		pr_info("%s: No partitions found, error %d\n", __func__, count);
> > @@ -1254,7 +1285,7 @@ static int ffa_setup_partitions(void)
> >  		import_uuid(&uuid, (u8 *)tpbuf->uuid);
> > 
> >  		/* Note that if the UUID will be uuid_null, that will require
> > -		 * ffa_device_match() to find the UUID of this partition id
> > +		 * ffa_bus_notifier() to find the UUID of this partition id
> >  		 * with help of ffa_device_match_uuid(). FF-A v1.1 and above
> >  		 * provides UUID here for each partition as part of the
> >  		 * discovery API and the same is passed.
> > --
> > 2.43.2
> > 
> 
> Also I wonder if we should have the change from patch 2 (the one which
> removes the ffa_device_match_uuid call from ffa_device_match) inside
> this. Wdyth ?
> 

I think so, again missed to see this as I had it in reverse order until
I was about to push the patches out. I realised the order can be swapped
actually without breaking the bisection but missed this. That's why you
see my note in 2/2 instead of 1/2
diff mbox series

Patch

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index 9f89ee0aaa6b..159f2106a541 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -1235,6 +1235,29 @@  void ffa_device_match_uuid(struct ffa_device *ffa_dev, const uuid_t *uuid)
 	kfree(pbuf);
 }

+static int
+ffa_bus_notifier(struct notifier_block *nb, unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct ffa_device *fdev = to_ffa_dev(dev);
+
+	if (action == BUS_NOTIFY_BIND_DRIVER) {
+		struct ffa_driver *ffa_drv = to_ffa_driver(dev->driver);
+		const struct ffa_device_id *id_table = ffa_drv->id_table;
+
+		if (uuid_is_null(&fdev->uuid))
+			ffa_device_match_uuid(fdev, &id_table->uuid);
+
+		return NOTIFY_OK;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block ffa_bus_nb = {
+	.notifier_call = ffa_bus_notifier,
+};
+
 static int ffa_setup_partitions(void)
 {
 	int count, idx, ret;
@@ -1243,6 +1266,14 @@  static int ffa_setup_partitions(void)
 	struct ffa_dev_part_info *info;
 	struct ffa_partition_info *pbuf, *tpbuf;

+	if (drv_info->version == FFA_VERSION_1_0) {
+		ret = bus_register_notifier(&ffa_bus_type, &ffa_bus_nb);
+		if (ret) {
+			pr_err("Failed to register FF-A bus notifiers\n");
+			return ret;
+		}
+	}
+
 	count = ffa_partition_probe(&uuid_null, &pbuf);
 	if (count <= 0) {
 		pr_info("%s: No partitions found, error %d\n", __func__, count);
@@ -1254,7 +1285,7 @@  static int ffa_setup_partitions(void)
 		import_uuid(&uuid, (u8 *)tpbuf->uuid);

 		/* Note that if the UUID will be uuid_null, that will require
-		 * ffa_device_match() to find the UUID of this partition id
+		 * ffa_bus_notifier() to find the UUID of this partition id
 		 * with help of ffa_device_match_uuid(). FF-A v1.1 and above
 		 * provides UUID here for each partition as part of the
 		 * discovery API and the same is passed.