Message ID | 11834551.O9o76ZdvQC@kreacher |
---|---|
State | New |
Headers | show |
Series | PCI: VMD: ACPI: Make ACPI companion lookup work for VMD bus | expand |
> On Aug 20, 2021, at 11:12 AM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > On some systems, in order to get to the deepest low-power state of > the platform (which may be necessary to save significant enough > amounts of energy while suspended to idle. for example), devices on > the PCI bus exposed by the VMD driver need to be power-managed via > ACPI. However, the layout of the ACPI namespace below the VMD > controller device object does not reflect the layout of the PCI bus > under the VMD host bridge, so in order to identify the ACPI companion > objects for the devices on that bus, it is necessary to use a special > _ADR encoding on the ACPI side. In other words, acpi_pci_find_companion() > does not work for these devices, so it needs to be amended with a > special lookup logic specific to the VMD bus. > > Address this issue by allowing the VMD driver to temporarily install > an ACPI companion lookup hook containing the code matching the devices > on the VMD PCI bus with the corresponding objects in the ACPI > namespace. > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > Tested-by: Wendy Wang <wendy.wang@intel.com> > --- > drivers/pci/controller/vmd.c | 48 ++++++++++++++++++++++++++ > drivers/pci/host-bridge.c | 1 > drivers/pci/pci-acpi.c | 78 +++++++++++++++++++++++++++++++++++++++++++ > include/linux/pci-acpi.h | 3 + > 4 files changed, 130 insertions(+) > > Index: linux-pm/drivers/pci/controller/vmd.c > =================================================================== > --- linux-pm.orig/drivers/pci/controller/vmd.c > +++ linux-pm/drivers/pci/controller/vmd.c > @@ -11,6 +11,7 @@ > #include <linux/module.h> > #include <linux/msi.h> > #include <linux/pci.h> > +#include <linux/pci-acpi.h> > #include <linux/pci-ecam.h> > #include <linux/srcu.h> > #include <linux/rculist.h> > @@ -447,6 +448,49 @@ static struct pci_ops vmd_ops = { > .write = vmd_pci_write, > }; > > +#ifdef CONFIG_ACPI > +static struct acpi_device *vmd_acpi_find_companion(struct pci_dev *pci_dev) > +{ > + struct pci_host_bridge *bridge; > + u32 busnr, addr; > + > + if (pci_dev->bus->ops != &vmd_ops) > + return NULL; Can we use is_vmd(pci_dev->bus)? > + > + bridge = pci_find_host_bridge(pci_dev->bus); > + busnr = pci_dev->bus->number - bridge->bus->number; This is just the bus->number - vmd->busn_start, correct? > + addr = (busnr << 24) | ((u32)pci_dev->devfn << 16) | 0x8000FFFFU; So the descriptor assumes busnr < 128 and requires an appropriately sized CFGBAR. Client is typically limited to 32 sub device buses but I’m not certain if enterprise will ever need > 128 (256 is allowed). > + > + dev_dbg(&pci_dev->dev, "Looking for ACPI companion (address 0x%x)\n", > + addr); > + > + return acpi_find_child_device(ACPI_COMPANION(bridge->dev.parent), addr, > + false); > +} > + > +static bool hook_installed; > + > +static void vmd_acpi_begin(void) > +{ > + if (pci_acpi_set_companion_lookup_hook(vmd_acpi_find_companion)) > + return; > + > + hook_installed = true; > +} > + > +static void vmd_acpi_end(void) > +{ > + if (!hook_installed) > + return; > + > + pci_acpi_clear_companion_lookup_hook(); > + hook_installed = false; > +} > +#else > +static inline void vmd_acpi_begin(void) { } > +static inline void vmd_acpi_end(void) { } > +#endif /* CONFIG_ACPI */ > + > static void vmd_attach_resources(struct vmd_dev *vmd) > { > vmd->dev->resource[VMD_MEMBAR1].child = &vmd->resources[1]; > @@ -747,6 +791,8 @@ static int vmd_enable_domain(struct vmd_ > if (vmd->irq_domain) > dev_set_msi_domain(&vmd->bus->dev, vmd->irq_domain); > > + vmd_acpi_begin(); > + > pci_scan_child_bus(vmd->bus); > pci_assign_unassigned_bus_resources(vmd->bus); > > @@ -760,6 +806,8 @@ static int vmd_enable_domain(struct vmd_ > > pci_bus_add_devices(vmd->bus); > > + vmd_acpi_end(); > + > WARN(sysfs_create_link(&vmd->dev->dev.kobj, &vmd->bus->dev.kobj, > "domain"), "Can't create symlink to domain\n"); > return 0; > Index: linux-pm/drivers/pci/host-bridge.c > =================================================================== > --- linux-pm.orig/drivers/pci/host-bridge.c > +++ linux-pm/drivers/pci/host-bridge.c > @@ -23,6 +23,7 @@ struct pci_host_bridge *pci_find_host_br > > return to_pci_host_bridge(root_bus->bridge); > } > +EXPORT_SYMBOL_GPL(pci_find_host_bridge); > > struct device *pci_get_host_bridge_device(struct pci_dev *dev) > { > Index: linux-pm/drivers/pci/pci-acpi.c > =================================================================== > --- linux-pm.orig/drivers/pci/pci-acpi.c > +++ linux-pm/drivers/pci/pci-acpi.c > @@ -1159,6 +1159,72 @@ void acpi_pci_remove_bus(struct pci_bus > } > > /* ACPI bus type */ > + > + > +DEFINE_STATIC_KEY_FALSE(pci_acpi_companion_lookup_key); > +static DEFINE_MUTEX(pci_acpi_companion_lookup_mtx); > +static struct acpi_device *(*pci_acpi_find_companion_hook)(struct pci_dev *); Wouldn’t a hook list be a better structure? Or is that too heavy handed for the purpose? > + > +/** > + * pci_acpi_set_companion_lookup_hook - Set ACPI companion lookup callback. > + * @func: ACPI companion lookup callback pointer or NULL. > + * > + * Set a special ACPI companion lookup callback for PCI devices whose companion > + * objects in the ACPI namespace have _ADR with non-standard bus-device-function > + * encodings. > + * > + * Return 0 on success or a negative error code on failure (in which case no > + * changes are made). > + * > + * The caller is responsible for the appropriate ordering of the invocations of > + * this function with respect to the enumeration of the PCI devices needing the > + * callback installed by it. > + */ > +int pci_acpi_set_companion_lookup_hook(struct acpi_device *(*func)(struct pci_dev *)) > +{ > + int ret; > + > + if (!func) > + return -EINVAL; > + > + mutex_lock(&pci_acpi_companion_lookup_mtx); > + > + if (pci_acpi_find_companion_hook) { > + ret = -EBUSY; > + } else { > + pci_acpi_find_companion_hook = func; > + static_branch_enable(&pci_acpi_companion_lookup_key); > + ret = 0; > + } > + > + mutex_unlock(&pci_acpi_companion_lookup_mtx); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(pci_acpi_set_companion_lookup_hook); > + > +/** > + * pci_acpi_clear_companion_lookup_hook - Clear ACPI companion lookup callback. > + * > + * Clear the special ACPI companion lookup callback previously set by > + * pci_acpi_set_companion_lookup_hook(). Block until the last running instance > + * of the callback returns before clearing it. > + * > + * The caller is responsible for the appropriate ordering of the invocations of > + * this function with respect to the enumeration of the PCI devices needing the > + * callback cleared by it. > + */ > +void pci_acpi_clear_companion_lookup_hook(void) > +{ > + mutex_lock(&pci_acpi_companion_lookup_mtx); > + > + pci_acpi_find_companion_hook = NULL; > + static_branch_disable(&pci_acpi_companion_lookup_key); > + > + mutex_unlock(&pci_acpi_companion_lookup_mtx); > +} > +EXPORT_SYMBOL_GPL(pci_acpi_clear_companion_lookup_hook); > + > static struct acpi_device *acpi_pci_find_companion(struct device *dev) > { > struct pci_dev *pci_dev = to_pci_dev(dev); > @@ -1166,6 +1232,18 @@ static struct acpi_device *acpi_pci_find > bool check_children; > u64 addr; > > + if (static_branch_unlikely(&pci_acpi_companion_lookup_key)) { > + mutex_lock(&pci_acpi_companion_lookup_mtx); > + > + adev = pci_acpi_find_companion_hook ? > + pci_acpi_find_companion_hook(pci_dev) : NULL; > + > + mutex_unlock(&pci_acpi_companion_lookup_mtx); > + > + if (adev) > + return adev; > + } > + > check_children = pci_is_bridge(pci_dev); > /* Please ref to ACPI spec for the syntax of _ADR */ > addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn); > Index: linux-pm/include/linux/pci-acpi.h > =================================================================== > --- linux-pm.orig/include/linux/pci-acpi.h > +++ linux-pm/include/linux/pci-acpi.h > @@ -122,6 +122,9 @@ static inline void pci_acpi_add_edr_noti > static inline void pci_acpi_remove_edr_notifier(struct pci_dev *pdev) { } > #endif /* CONFIG_PCIE_EDR */ > > +int pci_acpi_set_companion_lookup_hook(struct acpi_device *(*func)(struct pci_dev *)); > +void pci_acpi_clear_companion_lookup_hook(void); > + > #else /* CONFIG_ACPI */ > static inline void acpi_pci_add_bus(struct pci_bus *bus) { } > static inline void acpi_pci_remove_bus(struct pci_bus *bus) { }
On Fri, Aug 20, 2021 at 7:16 PM Jon Derrick <jonathan.derrick@linux.dev> wrote: > > > > > On Aug 20, 2021, at 11:12 AM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > > > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > > > On some systems, in order to get to the deepest low-power state of > > the platform (which may be necessary to save significant enough > > amounts of energy while suspended to idle. for example), devices on > > the PCI bus exposed by the VMD driver need to be power-managed via > > ACPI. However, the layout of the ACPI namespace below the VMD > > controller device object does not reflect the layout of the PCI bus > > under the VMD host bridge, so in order to identify the ACPI companion > > objects for the devices on that bus, it is necessary to use a special > > _ADR encoding on the ACPI side. In other words, acpi_pci_find_companion() > > does not work for these devices, so it needs to be amended with a > > special lookup logic specific to the VMD bus. > > > > Address this issue by allowing the VMD driver to temporarily install > > an ACPI companion lookup hook containing the code matching the devices > > on the VMD PCI bus with the corresponding objects in the ACPI > > namespace. > > > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > Tested-by: Wendy Wang <wendy.wang@intel.com> > > --- > > drivers/pci/controller/vmd.c | 48 ++++++++++++++++++++++++++ > > drivers/pci/host-bridge.c | 1 > > drivers/pci/pci-acpi.c | 78 +++++++++++++++++++++++++++++++++++++++++++ > > include/linux/pci-acpi.h | 3 + > > 4 files changed, 130 insertions(+) > > > > Index: linux-pm/drivers/pci/controller/vmd.c > > =================================================================== > > --- linux-pm.orig/drivers/pci/controller/vmd.c > > +++ linux-pm/drivers/pci/controller/vmd.c > > @@ -11,6 +11,7 @@ > > #include <linux/module.h> > > #include <linux/msi.h> > > #include <linux/pci.h> > > +#include <linux/pci-acpi.h> > > #include <linux/pci-ecam.h> > > #include <linux/srcu.h> > > #include <linux/rculist.h> > > @@ -447,6 +448,49 @@ static struct pci_ops vmd_ops = { > > .write = vmd_pci_write, > > }; > > > > +#ifdef CONFIG_ACPI > > +static struct acpi_device *vmd_acpi_find_companion(struct pci_dev *pci_dev) > > +{ > > + struct pci_host_bridge *bridge; > > + u32 busnr, addr; > > + > > + if (pci_dev->bus->ops != &vmd_ops) > > + return NULL; > Can we use is_vmd(pci_dev->bus)? Sure. > > + > > + bridge = pci_find_host_bridge(pci_dev->bus); > > + busnr = pci_dev->bus->number - bridge->bus->number; > This is just the bus->number - vmd->busn_start, correct? Yes, it is, but vmd is not known here AFAICS. > > > + addr = (busnr << 24) | ((u32)pci_dev->devfn << 16) | 0x8000FFFFU; > So the descriptor assumes busnr < 128 and requires an appropriately sized CFGBAR. Client is typically limited to 32 sub device buses but I’m not certain if enterprise will ever need > 128 (256 is allowed). It actually assumes busnr < 32. Well, that's what the formula is, but I need to return NULL if > 31. I'm not expecting the ACPI objects to be present on servers even. > > + > > + dev_dbg(&pci_dev->dev, "Looking for ACPI companion (address 0x%x)\n", > > + addr); > > + > > + return acpi_find_child_device(ACPI_COMPANION(bridge->dev.parent), addr, > > + false); > > +} > > + > > +static bool hook_installed; > > + > > +static void vmd_acpi_begin(void) > > +{ > > + if (pci_acpi_set_companion_lookup_hook(vmd_acpi_find_companion)) > > + return; > > + > > + hook_installed = true; > > +} > > + > > +static void vmd_acpi_end(void) > > +{ > > + if (!hook_installed) > > + return; > > + > > + pci_acpi_clear_companion_lookup_hook(); > > + hook_installed = false; > > +} > > +#else > > +static inline void vmd_acpi_begin(void) { } > > +static inline void vmd_acpi_end(void) { } > > +#endif /* CONFIG_ACPI */ > > + > > static void vmd_attach_resources(struct vmd_dev *vmd) > > { > > vmd->dev->resource[VMD_MEMBAR1].child = &vmd->resources[1]; > > @@ -747,6 +791,8 @@ static int vmd_enable_domain(struct vmd_ > > if (vmd->irq_domain) > > dev_set_msi_domain(&vmd->bus->dev, vmd->irq_domain); > > > > + vmd_acpi_begin(); > > + > > pci_scan_child_bus(vmd->bus); > > pci_assign_unassigned_bus_resources(vmd->bus); > > > > @@ -760,6 +806,8 @@ static int vmd_enable_domain(struct vmd_ > > > > pci_bus_add_devices(vmd->bus); > > > > + vmd_acpi_end(); > > + > > WARN(sysfs_create_link(&vmd->dev->dev.kobj, &vmd->bus->dev.kobj, > > "domain"), "Can't create symlink to domain\n"); > > return 0; > > Index: linux-pm/drivers/pci/host-bridge.c > > =================================================================== > > --- linux-pm.orig/drivers/pci/host-bridge.c > > +++ linux-pm/drivers/pci/host-bridge.c > > @@ -23,6 +23,7 @@ struct pci_host_bridge *pci_find_host_br > > > > return to_pci_host_bridge(root_bus->bridge); > > } > > +EXPORT_SYMBOL_GPL(pci_find_host_bridge); > > > > struct device *pci_get_host_bridge_device(struct pci_dev *dev) > > { > > Index: linux-pm/drivers/pci/pci-acpi.c > > =================================================================== > > --- linux-pm.orig/drivers/pci/pci-acpi.c > > +++ linux-pm/drivers/pci/pci-acpi.c > > @@ -1159,6 +1159,72 @@ void acpi_pci_remove_bus(struct pci_bus > > } > > > > /* ACPI bus type */ > > + > > + > > +DEFINE_STATIC_KEY_FALSE(pci_acpi_companion_lookup_key); > > +static DEFINE_MUTEX(pci_acpi_companion_lookup_mtx); > > +static struct acpi_device *(*pci_acpi_find_companion_hook)(struct pci_dev *); > Wouldn’t a hook list be a better structure? Or is that too heavy handed for the purpose? It might, but would that list ever contain more than 1 entry? If not, then it would be a redundant complication IMO. > > + > > +/** > > + * pci_acpi_set_companion_lookup_hook - Set ACPI companion lookup callback. > > + * @func: ACPI companion lookup callback pointer or NULL. > > + * > > + * Set a special ACPI companion lookup callback for PCI devices whose companion > > + * objects in the ACPI namespace have _ADR with non-standard bus-device-function > > + * encodings. > > + * > > + * Return 0 on success or a negative error code on failure (in which case no > > + * changes are made). > > + * > > + * The caller is responsible for the appropriate ordering of the invocations of > > + * this function with respect to the enumeration of the PCI devices needing the > > + * callback installed by it. > > + */ > > +int pci_acpi_set_companion_lookup_hook(struct acpi_device *(*func)(struct pci_dev *)) > > +{ > > + int ret; > > + > > + if (!func) > > + return -EINVAL; > > + > > + mutex_lock(&pci_acpi_companion_lookup_mtx); > > + > > + if (pci_acpi_find_companion_hook) { > > + ret = -EBUSY; > > + } else { > > + pci_acpi_find_companion_hook = func; > > + static_branch_enable(&pci_acpi_companion_lookup_key); > > + ret = 0; > > + } > > + > > + mutex_unlock(&pci_acpi_companion_lookup_mtx); > > + > > + return ret; > > +} > > +EXPORT_SYMBOL_GPL(pci_acpi_set_companion_lookup_hook); > > + > > +/** > > + * pci_acpi_clear_companion_lookup_hook - Clear ACPI companion lookup callback. > > + * > > + * Clear the special ACPI companion lookup callback previously set by > > + * pci_acpi_set_companion_lookup_hook(). Block until the last running instance > > + * of the callback returns before clearing it. > > + * > > + * The caller is responsible for the appropriate ordering of the invocations of > > + * this function with respect to the enumeration of the PCI devices needing the > > + * callback cleared by it. > > + */ > > +void pci_acpi_clear_companion_lookup_hook(void) > > +{ > > + mutex_lock(&pci_acpi_companion_lookup_mtx); > > + > > + pci_acpi_find_companion_hook = NULL; > > + static_branch_disable(&pci_acpi_companion_lookup_key); > > + > > + mutex_unlock(&pci_acpi_companion_lookup_mtx); > > +} > > +EXPORT_SYMBOL_GPL(pci_acpi_clear_companion_lookup_hook); > > + > > static struct acpi_device *acpi_pci_find_companion(struct device *dev) > > { > > struct pci_dev *pci_dev = to_pci_dev(dev); > > @@ -1166,6 +1232,18 @@ static struct acpi_device *acpi_pci_find > > bool check_children; > > u64 addr; > > > > + if (static_branch_unlikely(&pci_acpi_companion_lookup_key)) { > > + mutex_lock(&pci_acpi_companion_lookup_mtx); > > + > > + adev = pci_acpi_find_companion_hook ? > > + pci_acpi_find_companion_hook(pci_dev) : NULL; > > + > > + mutex_unlock(&pci_acpi_companion_lookup_mtx); > > + > > + if (adev) > > + return adev; > > + } > > + > > check_children = pci_is_bridge(pci_dev); > > /* Please ref to ACPI spec for the syntax of _ADR */ > > addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn); > > Index: linux-pm/include/linux/pci-acpi.h > > =================================================================== > > --- linux-pm.orig/include/linux/pci-acpi.h > > +++ linux-pm/include/linux/pci-acpi.h > > @@ -122,6 +122,9 @@ static inline void pci_acpi_add_edr_noti > > static inline void pci_acpi_remove_edr_notifier(struct pci_dev *pdev) { } > > #endif /* CONFIG_PCIE_EDR */ > > > > +int pci_acpi_set_companion_lookup_hook(struct acpi_device *(*func)(struct pci_dev *)); > > +void pci_acpi_clear_companion_lookup_hook(void); > > + > > #else /* CONFIG_ACPI */ > > static inline void acpi_pci_add_bus(struct pci_bus *bus) { } > > static inline void acpi_pci_remove_bus(struct pci_bus *bus) { }
Hi "Rafael,
I love your patch! Perhaps something to improve:
[auto build test WARNING on pci/next]
[also build test WARNING on pm/linux-next v5.14-rc6 next-20210820]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Rafael-J-Wysocki/PCI-VMD-ACPI-Make-ACPI-companion-lookup-work-for-VMD-bus/20210821-001443
base: https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git next
config: i386-randconfig-s032-20210821 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce:
# apt-get install sparse
# sparse version: v0.6.3-348-gf0e6938b-dirty
# https://github.com/0day-ci/linux/commit/0722ac93bc98deb9a9c445d7dfb78e7e068c9cb0
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Rafael-J-Wysocki/PCI-VMD-ACPI-Make-ACPI-companion-lookup-work-for-VMD-bus/20210821-001443
git checkout 0722ac93bc98deb9a9c445d7dfb78e7e068c9cb0
# save the attached .config to linux build tree
make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=i386 SHELL=/bin/bash drivers/pci/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
sparse warnings: (new ones prefixed by >>)
drivers/pci/pci-acpi.c:1019:64: sparse: sparse: restricted pci_power_t degrades to integer
>> drivers/pci/pci-acpi.c:1164:1: sparse: sparse: symbol 'pci_acpi_companion_lookup_key' was not declared. Should it be static?
Please review and possibly fold the followup patch.
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Index: linux-pm/drivers/pci/controller/vmd.c =================================================================== --- linux-pm.orig/drivers/pci/controller/vmd.c +++ linux-pm/drivers/pci/controller/vmd.c @@ -11,6 +11,7 @@ #include <linux/module.h> #include <linux/msi.h> #include <linux/pci.h> +#include <linux/pci-acpi.h> #include <linux/pci-ecam.h> #include <linux/srcu.h> #include <linux/rculist.h> @@ -447,6 +448,49 @@ static struct pci_ops vmd_ops = { .write = vmd_pci_write, }; +#ifdef CONFIG_ACPI +static struct acpi_device *vmd_acpi_find_companion(struct pci_dev *pci_dev) +{ + struct pci_host_bridge *bridge; + u32 busnr, addr; + + if (pci_dev->bus->ops != &vmd_ops) + return NULL; + + bridge = pci_find_host_bridge(pci_dev->bus); + busnr = pci_dev->bus->number - bridge->bus->number; + addr = (busnr << 24) | ((u32)pci_dev->devfn << 16) | 0x8000FFFFU; + + dev_dbg(&pci_dev->dev, "Looking for ACPI companion (address 0x%x)\n", + addr); + + return acpi_find_child_device(ACPI_COMPANION(bridge->dev.parent), addr, + false); +} + +static bool hook_installed; + +static void vmd_acpi_begin(void) +{ + if (pci_acpi_set_companion_lookup_hook(vmd_acpi_find_companion)) + return; + + hook_installed = true; +} + +static void vmd_acpi_end(void) +{ + if (!hook_installed) + return; + + pci_acpi_clear_companion_lookup_hook(); + hook_installed = false; +} +#else +static inline void vmd_acpi_begin(void) { } +static inline void vmd_acpi_end(void) { } +#endif /* CONFIG_ACPI */ + static void vmd_attach_resources(struct vmd_dev *vmd) { vmd->dev->resource[VMD_MEMBAR1].child = &vmd->resources[1]; @@ -747,6 +791,8 @@ static int vmd_enable_domain(struct vmd_ if (vmd->irq_domain) dev_set_msi_domain(&vmd->bus->dev, vmd->irq_domain); + vmd_acpi_begin(); + pci_scan_child_bus(vmd->bus); pci_assign_unassigned_bus_resources(vmd->bus); @@ -760,6 +806,8 @@ static int vmd_enable_domain(struct vmd_ pci_bus_add_devices(vmd->bus); + vmd_acpi_end(); + WARN(sysfs_create_link(&vmd->dev->dev.kobj, &vmd->bus->dev.kobj, "domain"), "Can't create symlink to domain\n"); return 0; Index: linux-pm/drivers/pci/host-bridge.c =================================================================== --- linux-pm.orig/drivers/pci/host-bridge.c +++ linux-pm/drivers/pci/host-bridge.c @@ -23,6 +23,7 @@ struct pci_host_bridge *pci_find_host_br return to_pci_host_bridge(root_bus->bridge); } +EXPORT_SYMBOL_GPL(pci_find_host_bridge); struct device *pci_get_host_bridge_device(struct pci_dev *dev) { Index: linux-pm/drivers/pci/pci-acpi.c =================================================================== --- linux-pm.orig/drivers/pci/pci-acpi.c +++ linux-pm/drivers/pci/pci-acpi.c @@ -1159,6 +1159,72 @@ void acpi_pci_remove_bus(struct pci_bus } /* ACPI bus type */ + + +DEFINE_STATIC_KEY_FALSE(pci_acpi_companion_lookup_key); +static DEFINE_MUTEX(pci_acpi_companion_lookup_mtx); +static struct acpi_device *(*pci_acpi_find_companion_hook)(struct pci_dev *); + +/** + * pci_acpi_set_companion_lookup_hook - Set ACPI companion lookup callback. + * @func: ACPI companion lookup callback pointer or NULL. + * + * Set a special ACPI companion lookup callback for PCI devices whose companion + * objects in the ACPI namespace have _ADR with non-standard bus-device-function + * encodings. + * + * Return 0 on success or a negative error code on failure (in which case no + * changes are made). + * + * The caller is responsible for the appropriate ordering of the invocations of + * this function with respect to the enumeration of the PCI devices needing the + * callback installed by it. + */ +int pci_acpi_set_companion_lookup_hook(struct acpi_device *(*func)(struct pci_dev *)) +{ + int ret; + + if (!func) + return -EINVAL; + + mutex_lock(&pci_acpi_companion_lookup_mtx); + + if (pci_acpi_find_companion_hook) { + ret = -EBUSY; + } else { + pci_acpi_find_companion_hook = func; + static_branch_enable(&pci_acpi_companion_lookup_key); + ret = 0; + } + + mutex_unlock(&pci_acpi_companion_lookup_mtx); + + return ret; +} +EXPORT_SYMBOL_GPL(pci_acpi_set_companion_lookup_hook); + +/** + * pci_acpi_clear_companion_lookup_hook - Clear ACPI companion lookup callback. + * + * Clear the special ACPI companion lookup callback previously set by + * pci_acpi_set_companion_lookup_hook(). Block until the last running instance + * of the callback returns before clearing it. + * + * The caller is responsible for the appropriate ordering of the invocations of + * this function with respect to the enumeration of the PCI devices needing the + * callback cleared by it. + */ +void pci_acpi_clear_companion_lookup_hook(void) +{ + mutex_lock(&pci_acpi_companion_lookup_mtx); + + pci_acpi_find_companion_hook = NULL; + static_branch_disable(&pci_acpi_companion_lookup_key); + + mutex_unlock(&pci_acpi_companion_lookup_mtx); +} +EXPORT_SYMBOL_GPL(pci_acpi_clear_companion_lookup_hook); + static struct acpi_device *acpi_pci_find_companion(struct device *dev) { struct pci_dev *pci_dev = to_pci_dev(dev); @@ -1166,6 +1232,18 @@ static struct acpi_device *acpi_pci_find bool check_children; u64 addr; + if (static_branch_unlikely(&pci_acpi_companion_lookup_key)) { + mutex_lock(&pci_acpi_companion_lookup_mtx); + + adev = pci_acpi_find_companion_hook ? + pci_acpi_find_companion_hook(pci_dev) : NULL; + + mutex_unlock(&pci_acpi_companion_lookup_mtx); + + if (adev) + return adev; + } + check_children = pci_is_bridge(pci_dev); /* Please ref to ACPI spec for the syntax of _ADR */ addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn); Index: linux-pm/include/linux/pci-acpi.h =================================================================== --- linux-pm.orig/include/linux/pci-acpi.h +++ linux-pm/include/linux/pci-acpi.h @@ -122,6 +122,9 @@ static inline void pci_acpi_add_edr_noti static inline void pci_acpi_remove_edr_notifier(struct pci_dev *pdev) { } #endif /* CONFIG_PCIE_EDR */ +int pci_acpi_set_companion_lookup_hook(struct acpi_device *(*func)(struct pci_dev *)); +void pci_acpi_clear_companion_lookup_hook(void); + #else /* CONFIG_ACPI */ static inline void acpi_pci_add_bus(struct pci_bus *bus) { } static inline void acpi_pci_remove_bus(struct pci_bus *bus) { }