[PATCH v3 4/4] ARM/PCI: remove arch specific pcibios_enable_device()
From: helgaas@kernel.org (Bjorn Helgaas)
Date: 2016-06-22 23:07:46
Also in:
linux-pci
[+cc Guan] On Wed, Jun 08, 2016 at 12:04:50PM +0100, Lorenzo Pieralisi wrote:
The arm pcibios_enable_device() implementation exists solely
to prevent enabling PCI resources on PCI_PROBE_ONLY systems, since
on those systems the PCI resources are currently not claimed (ie
inserted in the PCI resource tree - which means their parent
pointer is not correctly set-up) therefore they can not be enabled
since this would trigger PCI set-ups failures.
After removing the pci=firmware command line option in:
commit 903589ca7165 ("ARM: 8554/1: kernel: pci: remove pci=firmware
command line parameter handling")903589ca7165 removed "pci=firmware" from ARM and from Documentation/kernel-parameters.txt (where it was documented as ARM-specific). I think unicore32 copied that code from arm, so unicore32 is one of the few remaining arches that can set PCI_PROBE_ONLY. I suspect this was just copied from arm and may not be necessary on unicore32. Guan, can you confirm that PCI_PROBE_ONLY is necessary on unicore32, or that it can be removed?
quoted hunk ↗ jump to hunk
(that was used to set the PCI_PROBE_ONLY flag through the command line) and by introducing resources claiming in the PCI host controllers set-ups that have PCI_PROBE_ONLY as a probe option, there is no need for arch specific pcibios_enable_device() implementations anymore in that the kernel can rely on the generic pcibios_enable_device() implementation without resorting to arch specific code to work around the missing resources claiming enumeration step. On !PCI_PROBE_ONLY PCI bus set-ups, resources are always assigned either in pcibios initialization code or PCI host controllers drivers; since the PCI resource assignment API takes care of inserting the assigned resources in the resource tree, the resources parent pointers are correctly set-up, which means that this patch leaves behaviour unchanged for all arm PCI set-ups that do not set the PCI_PROBE_ONLY flag. Remove the pcibios_enable_device() function from the arm arch back-end so that the kernel now uses its generic implementation. Signed-off-by: Lorenzo Pieralisi <redacted> Acked-by: Will Deacon <redacted> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Will Deacon <redacted> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Russell King <redacted> --- arch/arm/kernel/bios32.c | 12 ------------ 1 file changed, 12 deletions(-)diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c index 05e61a2..488545f 100644 --- a/arch/arm/kernel/bios32.c +++ b/arch/arm/kernel/bios32.c@@ -590,18 +590,6 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res, return start; } -/** - * pcibios_enable_device - Enable I/O and memory. - * @dev: PCI device to be enabled - */ -int pcibios_enable_device(struct pci_dev *dev, int mask) -{ - if (pci_has_flag(PCI_PROBE_ONLY)) - return 0; - - return pci_enable_resources(dev, mask); -} - int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma, enum pci_mmap_state mmap_state, int write_combine) {-- 2.6.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel at lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel