Messages in this thread Patch in this message | | | Subject | Re: [Xen-devel] [PATCH] xen: use PCI interfaces to request IO and MEM resources on platform device. | From | Ian Campbell <> | Date | Tue, 11 Jan 2011 13:01:24 +0000 |
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On Tue, 2011-01-11 at 12:48 +0000, Jan Beulich wrote: > >>> On 11.01.11 at 12:50, Ian Campbell <ian.campbell@citrix.com> wrote: > > This is the correct interface to use and something has broken the use > > of the previous incorrect interface (which fails because the request > > conflicts with the resources assigned for the PCI device itself > > instead of nesting like the PCI interfaces do). > > While I agree that using the PCI interface is preferable, I can't see > how this can make a functional difference: __pci_request_region() > calls request_region() for the port resource and > __request_mem_region() for the mmio one exactly like what was > open coded before (request_mem_region() being equivalent to > __request_mem_region(..., 0), so I don't follow how this fixes > anything
request_mem_region was failing, the requested region appeared to conflict with the top level "PCI mem" resource. I don't know why and I didn't investigate deeper because using the pci_* interfaces is correct in its own right.
The old way was correct circa 2.6.37-rc5 but broken in 2.6.37 final, there were a bunch of (reverts of) PCI resource changes in that window, If I had to make a guess I'd say it was something in there which did it.
> but half of the potentially incorrect use of "long" for > mmio_addr.
Hmm yes, that should probably have a better type, although we probably know it's going to be <4G. Can you spin a patch please?
> I'm mainly asking because if it really addresses some problem, > then unmodified_drivers/linux-2.6/platform-pci/platform-pci.c > in -unstable should probably get updated too.
Assuming the pci_* interfaces exist back as far as we care about for those drivers then I don't see why not to apply it.
Ian.
> > Jan > > > Signed-off-by: Ian Campbell <ian.campbell@citrix.com> > > Cc: stable@kernel.org # 2.6.37 only > > --- > > drivers/xen/platform-pci.c | 21 +++++++-------------- > > 1 files changed, 7 insertions(+), 14 deletions(-) > > > > diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c > > index c01b5dd..afbe041 100644 > > --- a/drivers/xen/platform-pci.c > > +++ b/drivers/xen/platform-pci.c > > @@ -105,7 +105,7 @@ static int __devinit platform_pci_init(struct pci_dev > > *pdev, > > const struct pci_device_id *ent) > > { > > int i, ret; > > - long ioaddr, iolen; > > + long ioaddr; > > long mmio_addr, mmio_len; > > unsigned int max_nr_gframes; > > > > @@ -114,7 +114,6 @@ static int __devinit platform_pci_init(struct pci_dev > > *pdev, > > return i; > > > > ioaddr = pci_resource_start(pdev, 0); > > - iolen = pci_resource_len(pdev, 0); > > > > mmio_addr = pci_resource_start(pdev, 1); > > mmio_len = pci_resource_len(pdev, 1); > > @@ -125,19 +124,13 @@ static int __devinit platform_pci_init(struct pci_dev > > *pdev, > > goto pci_out; > > } > > > > - if (request_mem_region(mmio_addr, mmio_len, DRV_NAME) == NULL) { > > - dev_err(&pdev->dev, "MEM I/O resource 0x%lx @ 0x%lx busy\n", > > - mmio_addr, mmio_len); > > - ret = -EBUSY; > > + ret = pci_request_region(pdev, 1, DRV_NAME); > > + if (ret < 0) > > goto pci_out; > > - } > > > > - if (request_region(ioaddr, iolen, DRV_NAME) == NULL) { > > - dev_err(&pdev->dev, "I/O resource 0x%lx @ 0x%lx busy\n", > > - iolen, ioaddr); > > - ret = -EBUSY; > > + ret = pci_request_region(pdev, 0, DRV_NAME); > > + if (ret < 0) > > goto mem_out; > > - } > > > > platform_mmio = mmio_addr; > > platform_mmiolen = mmio_len; > > @@ -169,9 +162,9 @@ static int __devinit platform_pci_init(struct pci_dev > > *pdev, > > return 0; > > > > out: > > - release_region(ioaddr, iolen); > > + pci_release_region(pdev, 0); > > mem_out: > > - release_mem_region(mmio_addr, mmio_len); > > + pci_release_region(pdev, 1); > > pci_out: > > pci_disable_device(pdev); > > return ret; > > > >
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