On Wednesday, May 04, 2016 10:10:58 AM Tomasz Nowicki wrote: > On 27.04.2016 04:45, Bjorn Helgaas wrote: > > [question for Rafael below] > > > > On Fri, Apr 15, 2016 at 07:06:36PM +0200, Tomasz Nowicki wrote: > >> Currently we have two platforms (x86 & ia64) capable of PCI ACPI host > >> bridge initialization. They both use arch-specific sysdata to pass down > >> parent device reference and both rely on NULL parent in > >> pci_create_root_bus() > >> to validate sysdata content. > >> > >> It looks hacky and prevents us from getting some firmware specific > >> info for PCI host controller based on its acpi_device structure > >> in generic pci_create_root_bus() function. However, we overcome that > >> blocker by passing down parent device via pci_create_root_bus parameter > >> (as the ACPI device type). Then we use ACPI_COMPANION_SET in core code > >> for ACPI boot method only. ACPI_COMPANION_SET is safe to run for all > >> cases DT, ACPI and DT&ACPI. > >> > >> Since now PCI core code is setting ACPI companion device for us, > >> x86 & ia64 specific ACPI companion device setting turns out to be dead now. > >> We can get rid of it, including related companion reference from > >> PCI sysdata structure. Aslo, PCI_CONTROLLER macro cannot return valid > >> companion device anymore. Therefore we need to convert its usage to > >> ACPI_COMPANION. > >> > >> Suggested-by: Lorenzo Pieralisi <[email protected]> > >> Signed-off-by: Tomasz Nowicki <[email protected]> > >> Reviewed-by: Lorenzo Pieralisi <[email protected]> > >> Tested-by: Duc Dang <[email protected]> > >> Tested-by: Dongdong Liu <[email protected]> > >> Tested-by: Hanjun Guo <[email protected]> > >> Tested-by: Graeme Gregory <[email protected]> > >> Tested-by: Sinan Kaya <[email protected]> > >> --- > >> arch/ia64/hp/common/sba_iommu.c | 2 +- > >> arch/ia64/include/asm/pci.h | 1 - > >> arch/ia64/pci/pci.c | 16 ---------------- > >> arch/ia64/sn/kernel/io_acpi_init.c | 4 ++-- > >> arch/x86/include/asm/pci.h | 3 --- > >> arch/x86/pci/acpi.c | 17 ----------------- > >> drivers/acpi/pci_root.c | 7 ++++++- > >> drivers/pci/probe.c | 2 ++ > >> 8 files changed, 11 insertions(+), 41 deletions(-) > >> > >> diff --git a/arch/ia64/hp/common/sba_iommu.c > >> b/arch/ia64/hp/common/sba_iommu.c > >> index a6d6190..78e4444 100644 > >> --- a/arch/ia64/hp/common/sba_iommu.c > >> +++ b/arch/ia64/hp/common/sba_iommu.c > >> @@ -1981,7 +1981,7 @@ sba_connect_bus(struct pci_bus *bus) > >> if (PCI_CONTROLLER(bus)->iommu) > >> return; > >> > >> - handle = acpi_device_handle(PCI_CONTROLLER(bus)->companion); > >> + handle = acpi_device_handle(ACPI_COMPANION(bus->bridge)); > >> if (!handle) > >> return; > >> > >> diff --git a/arch/ia64/include/asm/pci.h b/arch/ia64/include/asm/pci.h > >> index c0835b0..12423f4 100644 > >> --- a/arch/ia64/include/asm/pci.h > >> +++ b/arch/ia64/include/asm/pci.h > >> @@ -63,7 +63,6 @@ extern int pci_mmap_legacy_page_range(struct pci_bus > >> *bus, > >> #define pci_legacy_write platform_pci_legacy_write > >> > >> struct pci_controller { > >> - struct acpi_device *companion; > >> void *iommu; > >> int segment; > >> int node; /* nearest node with memory or NUMA_NO_NODE for > >> global allocation */ > >> diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c > >> index 8f6ac2f..978d6af 100644 > >> --- a/arch/ia64/pci/pci.c > >> +++ b/arch/ia64/pci/pci.c > >> @@ -301,28 +301,12 @@ struct pci_bus *pci_acpi_scan_root(struct > >> acpi_pci_root *root) > >> } > >> > >> info->controller.segment = root->segment; > >> - info->controller.companion = device; > >> info->controller.node = acpi_get_node(device->handle); > >> INIT_LIST_HEAD(&info->io_resources); > >> return acpi_pci_root_create(root, &pci_acpi_root_ops, > >> &info->common, &info->controller); > >> } > >> > >> -int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge) > >> -{ > >> - /* > >> - * We pass NULL as parent to pci_create_root_bus(), so if it is not NULL > >> - * here, pci_create_root_bus() has been called by someone else and > >> - * sysdata is likely to be different from what we expect. Let it go in > >> - * that case. > >> - */ > >> - if (!bridge->dev.parent) { > >> - struct pci_controller *controller = bridge->bus->sysdata; > >> - ACPI_COMPANION_SET(&bridge->dev, controller->companion); > >> - } > >> - return 0; > >> -} > >> - > >> void pcibios_fixup_device_resources(struct pci_dev *dev) > >> { > >> int idx; > >> diff --git a/arch/ia64/sn/kernel/io_acpi_init.c > >> b/arch/ia64/sn/kernel/io_acpi_init.c > >> index 231234c..e454492 100644 > >> --- a/arch/ia64/sn/kernel/io_acpi_init.c > >> +++ b/arch/ia64/sn/kernel/io_acpi_init.c > >> @@ -132,7 +132,7 @@ sn_get_bussoft_ptr(struct pci_bus *bus) > >> struct acpi_resource_vendor_typed *vendor; > >> > >> > >> - handle = acpi_device_handle(PCI_CONTROLLER(bus)->companion); > >> + handle = acpi_device_handle(ACPI_COMPANION(bus->bridge)); > >> status = acpi_get_vendor_resource(handle, METHOD_NAME__CRS, > >> &sn_uuid, &buffer); > >> if (ACPI_FAILURE(status)) { > >> @@ -360,7 +360,7 @@ sn_acpi_get_pcidev_info(struct pci_dev *dev, struct > >> pcidev_info **pcidev_info, > >> acpi_status status; > >> struct acpi_buffer name_buffer = { ACPI_ALLOCATE_BUFFER, NULL }; > >> > >> - rootbus_handle = acpi_device_handle(PCI_CONTROLLER(dev)->companion); > >> + rootbus_handle = acpi_device_handle(ACPI_COMPANION(dev->bus->bridge)); > >> status = acpi_evaluate_integer(rootbus_handle, METHOD_NAME__SEG, > >> NULL, > >> &segment); > >> if (ACPI_SUCCESS(status)) { > >> diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h > >> index 9ab7507..24de07d 100644 > >> --- a/arch/x86/include/asm/pci.h > >> +++ b/arch/x86/include/asm/pci.h > >> @@ -14,9 +14,6 @@ > >> struct pci_sysdata { > >> int domain; /* PCI domain */ > >> int node; /* NUMA node */ > >> -#ifdef CONFIG_ACPI > >> - struct acpi_device *companion; /* ACPI companion device */ > >> -#endif > >> #ifdef CONFIG_X86_64 > >> void *iommu; /* IOMMU private data */ > >> #endif > >> diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c > >> index 3cd6983..f4ca17a 100644 > >> --- a/arch/x86/pci/acpi.c > >> +++ b/arch/x86/pci/acpi.c > >> @@ -340,7 +340,6 @@ struct pci_bus *pci_acpi_scan_root(struct > >> acpi_pci_root *root) > >> struct pci_sysdata sd = { > >> .domain = domain, > >> .node = node, > >> - .companion = root->device > >> }; > >> > >> memcpy(bus->sysdata, &sd, sizeof(sd)); > >> @@ -355,7 +354,6 @@ struct pci_bus *pci_acpi_scan_root(struct > >> acpi_pci_root *root) > >> else { > >> info->sd.domain = domain; > >> info->sd.node = node; > >> - info->sd.companion = root->device; > >> bus = acpi_pci_root_create(root, &acpi_pci_root_ops, > >> &info->common, &info->sd); > >> } > >> @@ -373,21 +371,6 @@ struct pci_bus *pci_acpi_scan_root(struct > >> acpi_pci_root *root) > >> return bus; > >> } > >> > >> -int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge) > >> -{ > >> - /* > >> - * We pass NULL as parent to pci_create_root_bus(), so if it is not NULL > >> - * here, pci_create_root_bus() has been called by someone else and > >> - * sysdata is likely to be different from what we expect. Let it go in > >> - * that case. > >> - */ > >> - if (!bridge->dev.parent) { > >> - struct pci_sysdata *sd = bridge->bus->sysdata; > >> - ACPI_COMPANION_SET(&bridge->dev, sd->companion); > >> - } > >> - return 0; > >> -} > >> - > >> int __init pci_acpi_init(void) > >> { > >> struct pci_dev *dev = NULL; > >> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c > >> index ae3fe4e..4581e0e 100644 > >> --- a/drivers/acpi/pci_root.c > >> +++ b/drivers/acpi/pci_root.c > >> @@ -564,6 +564,11 @@ static int acpi_pci_root_add(struct acpi_device > >> *device, > >> } > >> } > >> > >> + /* > >> + * pci_create_root_bus() needs to detect the parent device type, > >> + * so initialize its companion data accordingly. > >> + */ > >> + ACPI_COMPANION_SET(&device->dev, device); > >> root->device = device; > >> root->segment = segment & 0xFFFF; > >> strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME); > >> @@ -846,7 +851,7 @@ struct pci_bus *acpi_pci_root_create(struct > >> acpi_pci_root *root, > >> > >> pci_acpi_root_add_resources(info); > >> pci_add_resource(&info->resources, &root->secondary); > >> - bus = pci_create_root_bus(NULL, busnum, ops->pci_ops, > >> + bus = pci_create_root_bus(&device->dev, busnum, ops->pci_ops, > >> sysdata, &info->resources); > > > > "device" here is a struct acpi_device *. Rafael, is that the right > > thing to do? I dimly recall proposing something similar long ago and > > that it turned out to be a bad idea. > > > > Joining Bjorn's question. Rafael, do you recall what was the issue here > from the past?
Yes, I do. Anything struct acpi_device doesn't represent a real device. It represents a firmware object that can be associated with a device. IOW, nothing under LNXSYSTM\:00/ should ever be used as the parent or sibling etc with respect to anything outside of that directory. In fact, the entire LNXSYSTM\:00/ should be located under /sys/firmware/acpi/ and it was a mistake to put it under /sys/devices/. One immediate consequence of the above change, AFAICS, would be that the whole PCI hierarchy would now hang under /sys/devices/LNXSYSTM\:00/LNXSYBUS\:00/PNP0A08\:00/ which would not make any sense whatever, because /sys/devices/LNXSYSTM\:00/LNXSYBUS\:00/PNP0A08\:00/physical_node already points to /sys/devices/pci0000\:00/. IOW, both PNP0A08\:00/ and pci0000\:00/ already represent the same thing, ie. the host bridge. If you want to have a parent for pci0000\:00/, you need a physical_node for LNXSYBUS\:00 and point to that as the parent from pci0000\:00/. That at least will lead to a sysfs hierarchy that makes sense, although it may break user space tools I suppose (which may be assuming that pci0000\:00/ will always be present directly under /sys/devices/). Thanks, Rafael
