Re: [PATCH 02/24] sparc/PCI: Remove pcibios_enable_device() as they do nothing extra

[John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>]

Hello Ilpo,

On Fri, 2025-08-22 at 17:55 +0300, Ilpo Järvinen wrote:
> Under arch/sparc/ there are multiple copies of pcibios_enable_device()
> but none of those seem to do anything extra beyond what
> pci_enable_resources() is supposed to do. These functions could lead to
> inconsistencies in behavior, especially now as pci_enable_resources()
> and the bridge window resource flags behavior are going to be altered
> by upcoming changes.
> 
> Remove all pcibios_enable_device() from arch/sparc/ so that PCI core
> can simply call into pci_enable_resources() instead using it's __weak
> version of pcibios_enable_device().
> 
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> ---
>  arch/sparc/kernel/leon_pci.c | 27 ---------------------------
>  arch/sparc/kernel/pci.c      | 27 ---------------------------
>  arch/sparc/kernel/pcic.c     | 27 ---------------------------
>  3 files changed, 81 deletions(-)
> 
> diff --git a/arch/sparc/kernel/leon_pci.c b/arch/sparc/kernel/leon_pci.c
> index 8de6646e9ce8..10934dfa987a 100644
> --- a/arch/sparc/kernel/leon_pci.c
> +++ b/arch/sparc/kernel/leon_pci.c
> @@ -60,30 +60,3 @@ void leon_pci_init(struct platform_device *ofdev, struct leon_pci_info *info)
>  	pci_assign_unassigned_resources();
>  	pci_bus_add_devices(root_bus);
>  }
> -
> -int pcibios_enable_device(struct pci_dev *dev, int mask)
> -{
> -	struct resource *res;
> -	u16 cmd, oldcmd;
> -	int i;
> -
> -	pci_read_config_word(dev, PCI_COMMAND, &cmd);
> -	oldcmd = cmd;
> -
> -	pci_dev_for_each_resource(dev, res, i) {
> -		/* Only set up the requested stuff */
> -		if (!(mask & (1<<i)))
> -			continue;
> -
> -		if (res->flags & IORESOURCE_IO)
> -			cmd |= PCI_COMMAND_IO;
> -		if (res->flags & IORESOURCE_MEM)
> -			cmd |= PCI_COMMAND_MEMORY;
> -	}
> -
> -	if (cmd != oldcmd) {
> -		pci_info(dev, "enabling device (%04x -> %04x)\n", oldcmd, cmd);
> -		pci_write_config_word(dev, PCI_COMMAND, cmd);
> -	}
> -	return 0;
> -}
> diff --git a/arch/sparc/kernel/pci.c b/arch/sparc/kernel/pci.c
> index ddac216a2aff..a9448088e762 100644
> --- a/arch/sparc/kernel/pci.c
> +++ b/arch/sparc/kernel/pci.c
> @@ -722,33 +722,6 @@ struct pci_bus *pci_scan_one_pbm(struct pci_pbm_info *pbm,
>  	return bus;
>  }
>  
> -int pcibios_enable_device(struct pci_dev *dev, int mask)
> -{
> -	struct resource *res;
> -	u16 cmd, oldcmd;
> -	int i;
> -
> -	pci_read_config_word(dev, PCI_COMMAND, &cmd);
> -	oldcmd = cmd;
> -
> -	pci_dev_for_each_resource(dev, res, i) {
> -		/* Only set up the requested stuff */
> -		if (!(mask & (1<<i)))
> -			continue;
> -
> -		if (res->flags & IORESOURCE_IO)
> -			cmd |= PCI_COMMAND_IO;
> -		if (res->flags & IORESOURCE_MEM)
> -			cmd |= PCI_COMMAND_MEMORY;
> -	}
> -
> -	if (cmd != oldcmd) {
> -		pci_info(dev, "enabling device (%04x -> %04x)\n", oldcmd, cmd);
> -		pci_write_config_word(dev, PCI_COMMAND, cmd);
> -	}
> -	return 0;
> -}
> -
>  /* Platform support for /proc/bus/pci/X/Y mmap()s. */
>  int pci_iobar_pfn(struct pci_dev *pdev, int bar, struct vm_area_struct *vma)
>  {
> diff --git a/arch/sparc/kernel/pcic.c b/arch/sparc/kernel/pcic.c
> index 25fe0a061732..3d54ad5656a4 100644
> --- a/arch/sparc/kernel/pcic.c
> +++ b/arch/sparc/kernel/pcic.c
> @@ -641,33 +641,6 @@ void pcibios_fixup_bus(struct pci_bus *bus)
>  	}
>  }
>  
> -int pcibios_enable_device(struct pci_dev *dev, int mask)
> -{
> -	struct resource *res;
> -	u16 cmd, oldcmd;
> -	int i;
> -
> -	pci_read_config_word(dev, PCI_COMMAND, &cmd);
> -	oldcmd = cmd;
> -
> -	pci_dev_for_each_resource(dev, res, i) {
> -		/* Only set up the requested stuff */
> -		if (!(mask & (1<<i)))
> -			continue;
> -
> -		if (res->flags & IORESOURCE_IO)
> -			cmd |= PCI_COMMAND_IO;
> -		if (res->flags & IORESOURCE_MEM)
> -			cmd |= PCI_COMMAND_MEMORY;
> -	}
> -
> -	if (cmd != oldcmd) {
> -		pci_info(dev, "enabling device (%04x -> %04x)\n", oldcmd, cmd);
> -		pci_write_config_word(dev, PCI_COMMAND, cmd);
> -	}
> -	return 0;
> -}
> -
>  /* Makes compiler happy */
>  static volatile int pcic_timer_dummy;

This change actually broke driver initialization on SPARC, see:

https://github.com/sparclinux/issues/issues/22

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
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