Re: [Resend] pcibios_add_platform_entries usage

[Bjorn Helgaas <bhelgaas@google.com>]

On Thu, Apr 17, 2014 at 07:46:15PM +0200, Sebastian Ott wrote:
> On Mon, 14 Apr 2014, Sebastian Ott wrote:
> > On Mon, 14 Apr 2014, Bjorn Helgaas wrote:
> > > On Mon, Apr 14, 2014 at 11:03:42AM +0200, Sebastian Ott wrote:
> > > > for pci on s390 we currently use pcibios_add_platform_entries to add
> > > > some arch specific attributes to pdevs. This has 2 downsides - it will
> > > > race with userspace which is triggered by udev events and expecting
> > > > these attributes (but that's a theoretical issue). More important to
> > > > me is that one cannot use attribute_groups with this. Both issues could
> > > > be addressed by using pdev->dev.groups and let the driver core handle
> > > > attribute creation.
> > > > 
> > > > So would it be ok if we set pdev->dev.groups in pcibios_add_device?
> > > > (It should be since it's not used by pci common code which uses bus_type,
> > > > dev_type, and class groups).
> > > 
> > > Hi Sebastian,
> > > 
> > > Sorry, I meant to respond to this earlier, but forgot.  This sounds
> > > reasonable to me, but Greg can give you a much better answer than I can.
> > > 
> > > Documentation/driver-model/device.txt says the dev->groups pointer
> > > should be set before calling device_register().  PCI calls
> > > device_initialize() and device_add() instead of using device_register(),
> > > and pcibios_add_device() looks like it happens at the right time:
> > > 
> > >     pci_scan_root_bus
> > >       pci_scan_child_bus
> > >         pci_scan_slot
> > >           pci_scan_single_device
> > >             pci_device_add
> > >               device_initialize
> > >               pcibios_add_device                # <---
> > >               device_add
> > >       pci_bus_add_devices
> > >         pci_bus_add_device
> > >           pci_create_sysfs_dev_files
> > >             pcibios_add_platform_entries        # 8d4cd0833107 (benh)
> > >           device_attach
> > > 
> > > I'm not sure why pci_create_sysfs_dev_files() is done later.  It seems
> > > like that should be done before device_add() as well.  Maybe it's
> > > because BARs might not be valid yet (that doesn't seem like a very good
> > > excuse, but it's all I can think of).
> > > 
> > > I assume that if you change s390, you'll also change microblaze and
> > > powerpc?  They look structurally similar to s390.
> > 
> > Yes, that sounds like a plan - this way we can get rid of
> > pcibios_add_platform_entries altogether. I'll send these patches soon.
> 
> Hm, pcibios_add_platform_entries for microblaze and power is identical
> and this OF stuff seems not to be arch specific. How about the following
> patch?
> 
> 
> pci: move open fabric devspec attribute to pci common code
> 
> Move the devspec OF attribute to pci common code's set of device
> attributes since it's not architecture dependent.
> As a side effect microblaze and powerpc no longer need to use
> pcibios_add_platform_entries.
> 
> Link: https://lkml.kernel.org/r/alpine.LFD.2.11.1404141101500.1529@denkbrett
> Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>

I applied this with Ben's ack to pci/misc for v3.16.

I don't see a corresponding s390 patch; did I miss it?  I don't want to
apply the "Remove pcibios_add_platform_entries()" patch until s390 is
fixed up too.

Bjorn

> ---
>  arch/microblaze/pci/pci-common.c |   20 --------------------
>  arch/powerpc/kernel/pci-common.c |   20 --------------------
>  drivers/pci/pci-sysfs.c          |   17 +++++++++++++++++
>  3 files changed, 17 insertions(+), 40 deletions(-)
> 
> --- a/arch/microblaze/pci/pci-common.c
> +++ b/arch/microblaze/pci/pci-common.c
> @@ -168,26 +168,6 @@ struct pci_controller *pci_find_hose_for
>  	return NULL;
>  }
>  
> -static ssize_t pci_show_devspec(struct device *dev,
> -		struct device_attribute *attr, char *buf)
> -{
> -	struct pci_dev *pdev;
> -	struct device_node *np;
> -
> -	pdev = to_pci_dev(dev);
> -	np = pci_device_to_OF_node(pdev);
> -	if (np == NULL || np->full_name == NULL)
> -		return 0;
> -	return sprintf(buf, "%s", np->full_name);
> -}
> -static DEVICE_ATTR(devspec, S_IRUGO, pci_show_devspec, NULL);
> -
> -/* Add sysfs properties */
> -int pcibios_add_platform_entries(struct pci_dev *pdev)
> -{
> -	return device_create_file(&pdev->dev, &dev_attr_devspec);
> -}
> -
>  void pcibios_set_master(struct pci_dev *dev)
>  {
>  	/* No special bus mastering setup handling */
> --- a/arch/powerpc/kernel/pci-common.c
> +++ b/arch/powerpc/kernel/pci-common.c
> @@ -201,26 +201,6 @@ struct pci_controller* pci_find_hose_for
>  	return NULL;
>  }
>  
> -static ssize_t pci_show_devspec(struct device *dev,
> -		struct device_attribute *attr, char *buf)
> -{
> -	struct pci_dev *pdev;
> -	struct device_node *np;
> -
> -	pdev = to_pci_dev (dev);
> -	np = pci_device_to_OF_node(pdev);
> -	if (np == NULL || np->full_name == NULL)
> -		return 0;
> -	return sprintf(buf, "%s", np->full_name);
> -}
> -static DEVICE_ATTR(devspec, S_IRUGO, pci_show_devspec, NULL);
> -
> -/* Add sysfs properties */
> -int pcibios_add_platform_entries(struct pci_dev *pdev)
> -{
> -	return device_create_file(&pdev->dev, &dev_attr_devspec);
> -}
> -
>  /*
>   * Reads the interrupt pin to determine if interrupt is use by card.
>   * If the interrupt is used, then gets the interrupt line from the
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -416,6 +416,20 @@ static ssize_t d3cold_allowed_show(struc
>  static DEVICE_ATTR_RW(d3cold_allowed);
>  #endif
>  
> +#ifdef CONFIG_OF
> +static ssize_t devspec_show(struct device *dev,
> +			    struct device_attribute *attr, char *buf)
> +{
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +	struct device_node *np = pci_device_to_OF_node(pdev);
> +
> +	if (np == NULL || np->full_name == NULL)
> +		return 0;
> +	return sprintf(buf, "%s", np->full_name);
> +}
> +static DEVICE_ATTR_RO(devspec);
> +#endif
> +
>  #ifdef CONFIG_PCI_IOV
>  static ssize_t sriov_totalvfs_show(struct device *dev,
>  				   struct device_attribute *attr,
> @@ -521,6 +535,9 @@ static struct attribute *pci_dev_attrs[]
>  #if defined(CONFIG_PM_RUNTIME) && defined(CONFIG_ACPI)
>  	&dev_attr_d3cold_allowed.attr,
>  #endif
> +#ifdef CONFIG_OF
> +	&dev_attr_devspec.attr,
> +#endif
>  	NULL,
>  };
>