Messages in this thread Patch in this message | | | Subject | Re: [PATCH V9 11/11] ARM64/PCI: Support for ACPI based PCI host controller | From | Tomasz Nowicki <> | Date | Wed, 23 Nov 2016 12:21:03 +0100 |
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Hi Bjorn,
On 23.11.2016 00:13, Bjorn Helgaas wrote: > Hi Tomasz, > > On Fri, Jun 10, 2016 at 09:55:19PM +0200, Tomasz Nowicki wrote: >> Implement pci_acpi_scan_root and other arch-specific call so that ARM64 >> can start using ACPI to setup and enumerate PCI buses. >> >> Prior to buses enumeration the pci_acpi_scan_root() implementation looks >> for configuration space start address (obtained through ACPI _CBA method or >> MCFG interface). If succeed, it uses ECAM library to create new mapping. >> Then it attaches generic ECAM ops (pci_generic_ecam_ops) which are used >> for accessing configuration space later on. >> ... > >> +static struct acpi_pci_root_ops acpi_pci_root_ops = { >> + .release_info = pci_acpi_generic_release_info, >> +}; >> + >> +/* Interface called from ACPI code to setup PCI host controller */ >> struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) >> { >> - /* TODO: Should be revisited when implementing PCI on ACPI */ >> - return NULL; >> + int node = acpi_get_node(root->device->handle); >> + struct acpi_pci_generic_root_info *ri; >> + struct pci_bus *bus, *child; >> + >> + ri = kzalloc_node(sizeof(*ri), GFP_KERNEL, node); >> + if (!ri) >> + return NULL; >> + >> + ri->cfg = pci_acpi_setup_ecam_mapping(root); >> + if (!ri->cfg) { >> + kfree(ri); >> + return NULL; >> + } >> + >> + acpi_pci_root_ops.pci_ops = &ri->cfg->ops->pci_ops; > > This has already been merged, but this isn't right, is it? We're > writing a host controller-specific pointer into the single system-wide > acpi_pci_root_ops, then passing it on to acpi_pci_root_create(). > > Today, I think ri->cfg->ops->pci_ops is always &pci_generic_ecam_ops, > from this path: > > ri->cfg = pci_acpi_setup_ecam_mapping > cfg = pci_ecam_create(..., &pci_generic_ecam_ops) > cfg = kzalloc(...) > cfg->ops = ops # &pci_generic_ecam_ops > > But we're about to merge the ECAM quirks series, which will mean it > may not be &pci_generic_ecam_ops. Even apart from the ECAM quirks, we > should avoid this pattern of putting device-specific info in a single > shared structure because it's too difficult to verify that it's > correct. >
Well spotted. I agree, we need to fix this. How about this: diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c index fb439c7..31c0e1c 100644 --- a/arch/arm64/kernel/pci.c +++ b/arch/arm64/kernel/pci.c @@ -152,33 +152,35 @@ static void pci_acpi_generic_release_info(struct acpi_pci_root_info *ci)
ri = container_of(ci, struct acpi_pci_generic_root_info, common); pci_ecam_free(ri->cfg); + kfree(ci->ops); kfree(ri); }
-static struct acpi_pci_root_ops acpi_pci_root_ops = { - .release_info = pci_acpi_generic_release_info, -}; - /* Interface called from ACPI code to setup PCI host controller */ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) { int node = acpi_get_node(root->device->handle); struct acpi_pci_generic_root_info *ri; struct pci_bus *bus, *child; + struct acpi_pci_root_ops *root_ops;
ri = kzalloc_node(sizeof(*ri), GFP_KERNEL, node); if (!ri) return NULL;
+ root_ops = kzalloc_node(sizeof(*root_ops), GFP_KERNEL, node); + if (!root_ops) + return NULL; + ri->cfg = pci_acpi_setup_ecam_mapping(root); if (!ri->cfg) { kfree(ri); + kfree(root_ops); return NULL; }
- acpi_pci_root_ops.pci_ops = &ri->cfg->ops->pci_ops; - bus = acpi_pci_root_create(root, &acpi_pci_root_ops, &ri->common, - ri->cfg); + root_ops->release_info = pci_acpi_generic_release_info; + root_ops->pci_ops = &ri->cfg->ops->pci_ops; + bus = acpi_pci_root_create(root, root_ops, &ri->common, ri->cfg); if (!bus) return NULL;
Of course, this should be the part of ECAM quirks core patches. The other option we have is to remove "struct pci_ops *pci_ops;" from acpi_pci_root_ops structure and pass struct pci_ops as an extra argument to acpi_pci_root_create(). What do you think?
Thanks, Tomasz
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