Re: [patch V2 16/23] PCI/MSI: Split out CONFIG_PCI_MSI independent part

[Bjorn Helgaas <helgaas@kernel.org>]

On Mon, Dec 06, 2021 at 11:27:49PM +0100, Thomas Gleixner wrote:
> These functions are required even when CONFIG_PCI_MSI is not set. Move them
> to their own file.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Tested-by: Juergen Gross <jgross@suse.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

> ---
>  drivers/pci/msi/Makefile     |    3 ++-
>  drivers/pci/msi/msi.c        |   39 ---------------------------------------
>  drivers/pci/msi/pcidev_msi.c |   43 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 45 insertions(+), 40 deletions(-)
> 
> --- a/drivers/pci/msi/Makefile
> +++ b/drivers/pci/msi/Makefile
> @@ -1,4 +1,5 @@
>  # SPDX-License-Identifier: GPL-2.0
>  #
>  # Makefile for the PCI/MSI
> -obj-$(CONFIG_PCI)		+= msi.o
> +obj-$(CONFIG_PCI)		+= pcidev_msi.o
> +obj-$(CONFIG_PCI_MSI)		+= msi.o
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -18,8 +18,6 @@
>  
>  #include "../pci.h"
>  
> -#ifdef CONFIG_PCI_MSI
> -
>  static int pci_msi_enable = 1;
>  int pci_msi_ignore_mask;
>  
> @@ -1493,40 +1491,3 @@ bool pci_dev_has_special_msi_domain(stru
>  }
>  
>  #endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */
> -#endif /* CONFIG_PCI_MSI */
> -
> -void pci_msi_init(struct pci_dev *dev)
> -{
> -	u16 ctrl;
> -
> -	/*
> -	 * Disable the MSI hardware to avoid screaming interrupts
> -	 * during boot.  This is the power on reset default so
> -	 * usually this should be a noop.
> -	 */
> -	dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
> -	if (!dev->msi_cap)
> -		return;
> -
> -	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &ctrl);
> -	if (ctrl & PCI_MSI_FLAGS_ENABLE)
> -		pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS,
> -				      ctrl & ~PCI_MSI_FLAGS_ENABLE);
> -
> -	if (!(ctrl & PCI_MSI_FLAGS_64BIT))
> -		dev->no_64bit_msi = 1;
> -}
> -
> -void pci_msix_init(struct pci_dev *dev)
> -{
> -	u16 ctrl;
> -
> -	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
> -	if (!dev->msix_cap)
> -		return;
> -
> -	pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &ctrl);
> -	if (ctrl & PCI_MSIX_FLAGS_ENABLE)
> -		pci_write_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS,
> -				      ctrl & ~PCI_MSIX_FLAGS_ENABLE);
> -}
> --- /dev/null
> +++ b/drivers/pci/msi/pcidev_msi.c
> @@ -0,0 +1,43 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * MSI[X} related functions which are available unconditionally.
> + */
> +#include "../pci.h"
> +
> +/*
> + * Disable the MSI[X] hardware to avoid screaming interrupts during boot.
> + * This is the power on reset default so usually this should be a noop.
> + */
> +
> +void pci_msi_init(struct pci_dev *dev)
> +{
> +	u16 ctrl;
> +
> +	dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
> +	if (!dev->msi_cap)
> +		return;
> +
> +	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &ctrl);
> +	if (ctrl & PCI_MSI_FLAGS_ENABLE) {
> +		pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS,
> +				      ctrl & ~PCI_MSI_FLAGS_ENABLE);
> +	}
> +
> +	if (!(ctrl & PCI_MSI_FLAGS_64BIT))
> +		dev->no_64bit_msi = 1;
> +}
> +
> +void pci_msix_init(struct pci_dev *dev)
> +{
> +	u16 ctrl;
> +
> +	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
> +	if (!dev->msix_cap)
> +		return;
> +
> +	pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &ctrl);
> +	if (ctrl & PCI_MSIX_FLAGS_ENABLE) {
> +		pci_write_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS,
> +				      ctrl & ~PCI_MSIX_FLAGS_ENABLE);
> +	}
> +}
>