Re: [PATCH 1/2] cxl: Deprecate driver

[Frederic Barrat <fbarrat@linux.ibm.com>]

On 10/12/2024 06:40, Andrew Donnellan wrote:
> The cxl driver is no longer actively maintained and we intend to remove it
> in a future kernel release.
> 
> cxl has received minimal maintenance for several years, and is not
> supported on the Power10 processor. We aren't aware of any users who are
> likely to be using recent kernels.
> 
> Change its MAINTAINERS status to obsolete, update the sysfs ABI
> documentation accordingly, add a warning message on device probe, change
> the Kconfig options to label it as deprecated, and don't build it by
> default.
> 
> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>


Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>

   Fred


> ---
>   Documentation/ABI/{testing => obsolete}/sysfs-class-cxl | 3 +++
>   MAINTAINERS                                             | 4 ++--
>   drivers/misc/cxl/Kconfig                                | 6 ++++--
>   drivers/misc/cxl/of.c                                   | 2 ++
>   drivers/misc/cxl/pci.c                                  | 2 ++
>   5 files changed, 13 insertions(+), 4 deletions(-)
>   rename Documentation/ABI/{testing => obsolete}/sysfs-class-cxl (99%)
> 
> diff --git a/Documentation/ABI/testing/sysfs-class-cxl b/Documentation/ABI/obsolete/sysfs-class-cxl
> similarity index 99%
> rename from Documentation/ABI/testing/sysfs-class-cxl
> rename to Documentation/ABI/obsolete/sysfs-class-cxl
> index cfc48a87706b..8cba1b626985 100644
> --- a/Documentation/ABI/testing/sysfs-class-cxl
> +++ b/Documentation/ABI/obsolete/sysfs-class-cxl
> @@ -1,3 +1,6 @@
> +The cxl driver is no longer maintained, and will be removed from the kernel in
> +the near future.
> +
>   Please note that attributes that are shared between devices are stored in
>   the directory pointed to by the symlink device/.
>   For example, the real path of the attribute /sys/class/cxl/afu0.0s/irqs_max is
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 17daa9ee9384..1737a8ff4f2b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6228,8 +6228,8 @@ CXL (IBM Coherent Accelerator Processor Interface CAPI) DRIVER
>   M:	Frederic Barrat <fbarrat@linux.ibm.com>
>   M:	Andrew Donnellan <ajd@linux.ibm.com>
>   L:	linuxppc-dev@lists.ozlabs.org
> -S:	Supported
> -F:	Documentation/ABI/testing/sysfs-class-cxl
> +S:	Obsolete
> +F:	Documentation/ABI/obsolete/sysfs-class-cxl
>   F:	Documentation/arch/powerpc/cxl.rst
>   F:	arch/powerpc/platforms/powernv/pci-cxl.c
>   F:	drivers/misc/cxl/
> diff --git a/drivers/misc/cxl/Kconfig b/drivers/misc/cxl/Kconfig
> index 5efc4151bf58..15307f5e4307 100644
> --- a/drivers/misc/cxl/Kconfig
> +++ b/drivers/misc/cxl/Kconfig
> @@ -9,11 +9,13 @@ config CXL_BASE
>   	select PPC_64S_HASH_MMU
>   
>   config CXL
> -	tristate "Support for IBM Coherent Accelerators (CXL)"
> +	tristate "Support for IBM Coherent Accelerators (CXL) (DEPRECATED)"
>   	depends on PPC_POWERNV && PCI_MSI && EEH
>   	select CXL_BASE
> -	default m
>   	help
> +	  The cxl driver is deprecated and will be removed in a future
> +	  kernel release.
> +
>   	  Select this option to enable driver support for IBM Coherent
>   	  Accelerators (CXL).  CXL is otherwise known as Coherent Accelerator
>   	  Processor Interface (CAPI).  CAPI allows accelerators in FPGAs to be
> diff --git a/drivers/misc/cxl/of.c b/drivers/misc/cxl/of.c
> index cf6bd8a43056..e26ee85279fa 100644
> --- a/drivers/misc/cxl/of.c
> +++ b/drivers/misc/cxl/of.c
> @@ -295,6 +295,8 @@ int cxl_of_probe(struct platform_device *pdev)
>   	int ret;
>   	int slice = 0, slice_ok = 0;
>   
> +	dev_err_once(&pdev->dev, "DEPRECATION: cxl is deprecated and will be removed in a future kernel release\n");
> +
>   	pr_devel("in %s\n", __func__);
>   
>   	np = pdev->dev.of_node;
> diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
> index 3d52f9b92d0d..92bf7c5c7b35 100644
> --- a/drivers/misc/cxl/pci.c
> +++ b/drivers/misc/cxl/pci.c
> @@ -1726,6 +1726,8 @@ static int cxl_probe(struct pci_dev *dev, const struct pci_device_id *id)
>   	int slice;
>   	int rc;
>   
> +	dev_err_once(&dev->dev, "DEPRECATED: cxl is deprecated and will be removed in a future kernel release\n");
> +
>   	if (cxl_pci_is_vphb_device(dev)) {
>   		dev_dbg(&dev->dev, "cxl_init_adapter: Ignoring cxl vphb device\n");
>   		return -ENODEV;