From: Greg KH <gregkh@linuxfoundation.org>
To: Nipun Gupta <nipun.gupta@amd.com>
Cc: robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
rafael@kernel.org, eric.auger@redhat.com,
alex.williamson@redhat.com, cohuck@redhat.com,
song.bao.hua@hisilicon.com, mchehab+huawei@kernel.org,
maz@kernel.org, f.fainelli@gmail.com, jeffrey.l.hugo@gmail.com,
saravanak@google.com, Michael.Srba@seznam.cz, mani@kernel.org,
yishaih@nvidia.com, jgg@ziepe.ca, jgg@nvidia.com,
robin.murphy@arm.com, will@kernel.org, joro@8bytes.org,
masahiroy@kernel.org, ndesaulniers@google.com,
linux-arm-kernel@lists.infradead.org,
linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org, okaya@kernel.org,
harpreet.anand@amd.com, nikhil.agarwal@amd.com,
michal.simek@amd.com, git@amd.com
Subject: Re: [PATCH 01/19] bus/cdx: add the cdx bus driver
Date: Tue, 17 Jan 2023 15:07:02 +0100 [thread overview]
Message-ID: <Y8arhmVo7LPLuxqr@kroah.com> (raw)
In-Reply-To: <20230117134139.1298-2-nipun.gupta@amd.com>
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@amd.com>
> Signed-off-by: Tarak Reddy <tarak.reddy@amd.com>
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
next prev parent reply other threads:[~2023-01-17 14:07 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-17 13:41 [PATCH 0/7] add support for CDX bus Nipun Gupta
2023-01-17 13:41 ` [PATCH 01/19] bus/cdx: add the cdx bus driver Nipun Gupta
2023-01-17 14:07 ` Greg KH [this message]
2023-01-18 10:56 ` Gupta, Nipun
2023-01-17 17:21 ` Randy Dunlap
2023-01-18 10:59 ` Gupta, Nipun
2023-01-17 13:41 ` [PATCH 02/19] iommu/arm-smmu-v3: support ops registration for CDX bus Nipun Gupta
2023-01-17 13:41 ` [PATCH 03/19] dt-bindings: bus: add CDX bus controller device tree bindings Nipun Gupta
2023-01-17 17:54 ` Krzysztof Kozlowski
2023-01-18 12:39 ` Gupta, Nipun
2023-01-18 12:43 ` Krzysztof Kozlowski
2023-01-19 7:33 ` Gupta, Nipun
2023-01-17 13:41 ` [PATCH 04/19] bus/cdx: add MCDI protocol interface for firmware interaction Nipun Gupta
2023-01-17 14:08 ` Greg KH
2023-01-18 10:58 ` Gupta, Nipun
2023-01-17 13:41 ` [PATCH 05/19] bus/cdx: add cdx controller Nipun Gupta
2023-01-17 14:10 ` Greg KH
2023-01-18 12:36 ` Gupta, Nipun
2023-01-17 13:41 ` [PATCH 06/19] bus/cdx: add rpmsg communication channel for CDX Nipun Gupta
2023-01-17 13:41 ` [PATCH 07/19] bus/cdx: add device attributes Nipun Gupta
2023-01-17 14:13 ` Greg KH
2023-01-18 13:03 ` Gupta, Nipun
2023-01-17 17:47 ` [PATCH 0/7] add support for CDX bus Krzysztof Kozlowski
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