On Tue, Jan 17, 2023 at 07:11:33PM +0530, Nipun Gupta wrote:
> Introduce AMD CDX bus, which provides a mechanism for scanning
> and probing CDX devices. These devices are memory mapped on
> system bus for Application Processors(APUs).
>
> CDX devices can be changed dynamically in the Fabric and CDX
> bus interacts with CDX controller to rescan the bus and
> rediscover the devices.
>
> Signed-off-by: Nipun Gupta <nipun.gupta@xxxxxxx>
> Signed-off-by: Tarak Reddy <tarak.reddy@xxxxxxx>
First off, very nice job, I didn't find any obvious issues with this
integration into the driver core.
That being said, why do you want this in drivers/bus/? Why not
drivers/cdx/ ?
One minor comment to make the code smaller:
> +static int get_free_index(void)
> +{
> + unsigned long id_map;
> + unsigned long mask;
> + int index = 0;
> +
> + mask = (1UL << MAX_CDX_CONTROLLERS) - 1;
> +retry:
> + id_map = cdx_controller_id_map[0];
> + if ((id_map & mask) == mask)
> + return -ENOSPC;
> +
> + index = ffz(id_map);
> + if (index >= MAX_CDX_CONTROLLERS)
> + return -ENOSPC;
> +
> + if (test_and_set_bit(index, &cdx_controller_id_map[0]))
> + goto retry;
> +
> + return index;
> +}
Why not just use the idr/ida structure instead? That will handle all of
that logic for you and get rid of your bit twiddling.
> +/**
> + * struct cdx_dev_params - CDX device parameters
> + * @cdx: CDX controller associated with the device
> + * @parent: Associated CDX controller
> + * @vendor: Vendor ID for CDX device
> + * @device: Device ID for CDX device
> + * @bus_num: Bus number for this CDX device
> + * @dev_num: Device number for this device
> + * @res: array of MMIO region entries
> + * @res_count: number of valid MMIO regions
> + * @req_id: Requestor ID associated with CDX device
> + */
> +struct cdx_dev_params {
> + struct cdx_controller *cdx;
> + u16 vendor;
> + u16 device;
Are these in little endian format in memory? Or native? Or something
else?
thanks,
greg k-h
