On Wed, Oct 18, 2023 at 11:12:12AM +0530, Umang Jain wrote:
> VC04 has now a independent bus vchiq_bus to register its devices.
> However, the module auto-loading for bcm2835-audio and bcm2835-camera
> currently happens through MODULE_ALIAS() macro specified explicitly.
>
> The correct way to auto-load a module, is when the alias is picked
> out from MODULE_DEVICE_TABLE(). In order to get there, we need to
> introduce vchiq_device_id and add relevant entries in file2alias.c
> infrastructure so that aliases can be generated. This patch targets
> adding vchiq_bus_device_id and do_vchiq_bus_entry, in order to
> generate those alias using the /script/mod/file2alias.c.
>
> Going forward the MODULE_ALIAS() from bcm2835-camera and bcm2835-audio
> will be dropped, in favour of MODULE_DEVICE_TABLE being used there.
>
> The alias format for vchiq_bus devices will be "vchiq_bus:<dev_name>".
> Adjust the vchiq_bus_uevent() to reflect that.
None of the other buses have a "_bus" suffix in the alias or in the
*_device_id structure name. Is there a reason to make an exception here?
> Signed-off-by: Umang Jain <umang.jain@xxxxxxxxxxxxxxxx>
> ---
> .../vc04_services/interface/vchiq_arm/vchiq_bus.c | 2 +-
> .../vc04_services/interface/vchiq_arm/vchiq_bus.h | 3 +++
> include/linux/mod_devicetable.h | 4 ++++
> scripts/mod/devicetable-offsets.c | 3 +++
> scripts/mod/file2alias.c | 9 +++++++++
> 5 files changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.c
> index 4ac3491efe45..b4915bd76387 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.c
> @@ -26,7 +26,7 @@ static int vchiq_bus_uevent(const struct device *dev, struct kobj_uevent_env *en
> {
> const struct vchiq_device *device = container_of_const(dev, struct vchiq_device, dev);
>
> - return add_uevent_var(env, "MODALIAS=%s", dev_name(&device->dev));
> + return add_uevent_var(env, "MODALIAS=vchiq_bus:%s", dev_name(&device->dev));
> }
>
> static int vchiq_bus_probe(struct device *dev)
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.h b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.h
> index 7eaaf9a91cda..6e1fbee4b078 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.h
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.h
> @@ -7,6 +7,7 @@
> #define _VCHIQ_DEVICE_H
>
> #include <linux/device.h>
> +#include <linux/mod_devicetable.h>
>
> struct vchiq_device {
> struct device dev;
> @@ -18,6 +19,8 @@ struct vchiq_driver {
> int (*resume)(struct vchiq_device *device);
> int (*suspend)(struct vchiq_device *device,
> pm_message_t state);
> +
> + const struct vchiq_bus_device_id *id_table;
> struct device_driver driver;
> };
>
> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> index b0678b093cb2..f01e175f7f3d 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -946,4 +946,8 @@ struct cdx_device_id {
> __u32 override_only;
> };
>
> +struct vchiq_bus_device_id {
> + char name[32];
> +};
> +
> #endif /* LINUX_MOD_DEVICETABLE_H */
> diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
> index abe65f8968dd..c9a02d2c4f9e 100644
> --- a/scripts/mod/devicetable-offsets.c
> +++ b/scripts/mod/devicetable-offsets.c
> @@ -267,5 +267,8 @@ int main(void)
> DEVID_FIELD(cdx_device_id, device);
> DEVID_FIELD(cdx_device_id, override_only);
>
> + DEVID(vchiq_bus_device_id);
> + DEVID_FIELD(vchiq_bus_device_id, name);
> +
> return 0;
> }
> diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
> index 38120f932b0d..6908dc70b649 100644
> --- a/scripts/mod/file2alias.c
> +++ b/scripts/mod/file2alias.c
> @@ -1478,6 +1478,14 @@ static int do_cdx_entry(const char *filename, void *symval,
> return 1;
> }
>
> +static int do_vchiq_bus_entry(const char *filename, void *symval, char *alias)
> +{
> + DEF_FIELD_ADDR(symval, vchiq_bus_device_id, name);
> + sprintf(alias, "vchiq_bus:%s", *name);
> +
> + return 1;
> +}
> +
> /* Does namelen bytes of name exactly match the symbol? */
> static bool sym_is(const char *name, unsigned namelen, const char *symbol)
> {
> @@ -1558,6 +1566,7 @@ static const struct devtable devtable[] = {
> {"dfl", SIZE_dfl_device_id, do_dfl_entry},
> {"ishtp", SIZE_ishtp_device_id, do_ishtp_entry},
> {"cdx", SIZE_cdx_device_id, do_cdx_entry},
> + {"vchiq_bus", SIZE_vchiq_bus_device_id, do_vchiq_bus_entry},
> };
>
> /* Create MODULE_ALIAS() statements.
--
Regards,
Laurent Pinchart
