| Message ID | 20241104-imx95_lut-v5-1-feb972f3f13b@nxp.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | PCI: add enabe(disable)_device() hook for bridge | expand |
On Mon, Nov 04, 2024 at 02:22:59PM -0500, Frank Li wrote: > Some PCIe host bridges require special handling when enabling or disabling > PCIe Endpoints. For example, the i.MX95 platform has a lookup table to map > Requester IDs to StreamIDs, which are used by the SMMU and MSI controller > to identify the source of DMA accesses. > > Without this mapping, DMA accesses may target unintended memory, which > would corrupt memory or read the wrong data. > > Add a host bridge .enable_device() hook the imx6 driver can use to > configure the Requester ID to StreamID mapping. The hardware table isn't > big enough to map all possible Requester IDs, so this hook may fail if no > table space is available. In that case, return failure from > pci_enable_device(). > > It might make more sense to make pci_set_master() decline to enable bus > mastering and return failure, but it currently doesn't have a way to return > failure. > > Signed-off-by: Frank Li <Frank.Li@nxp.com> Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> - Mani > --- > Change from v4 to v5 > - Add two static help functions > int pci_host_bridge_enable_device(dev); > void pci_host_bridge_disable_device(dev); > - remove tags because big change > Acked-by: Bjorn Helgaas <bhelgaas@google.com> > Reviewed-by: Marc Zyngier <maz@kernel.org> > Tested-by: Marc Zyngier <maz@kernel.org> > > Change from v3 to v4 > - Add Bjorn's ack tag > > Change from v2 to v3 > - use Bjorn suggest's commit message. > - call disable_device() when error happen. > > Change from v1 to v2 > - move enable(disable)device ops to pci_host_bridge > --- > drivers/pci/pci.c | 36 +++++++++++++++++++++++++++++++++++- > include/linux/pci.h | 2 ++ > 2 files changed, 37 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 67013df89a694..4735bc665ab3b 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -2055,6 +2055,28 @@ int __weak pcibios_enable_device(struct pci_dev *dev, int bars) > return pci_enable_resources(dev, bars); > } > > +static int pci_host_bridge_enable_device(struct pci_dev *dev) > +{ > + struct pci_host_bridge *host_bridge = pci_find_host_bridge(dev->bus); > + int err; > + > + if (host_bridge && host_bridge->enable_device) { > + err = host_bridge->enable_device(host_bridge, dev); > + if (err) > + return err; > + } > + > + return 0; > +} > + > +static void pci_host_bridge_disable_device(struct pci_dev *dev) > +{ > + struct pci_host_bridge *host_bridge = pci_find_host_bridge(dev->bus); > + > + if (host_bridge && host_bridge->disable_device) > + host_bridge->disable_device(host_bridge, dev); > +} > + > static int do_pci_enable_device(struct pci_dev *dev, int bars) > { > int err; > @@ -2070,9 +2092,13 @@ static int do_pci_enable_device(struct pci_dev *dev, int bars) > if (bridge) > pcie_aspm_powersave_config_link(bridge); > > + err = pci_host_bridge_enable_device(dev); > + if (err) > + return err; > + > err = pcibios_enable_device(dev, bars); > if (err < 0) > - return err; > + goto err_enable; > pci_fixup_device(pci_fixup_enable, dev); > > if (dev->msi_enabled || dev->msix_enabled) > @@ -2087,6 +2113,12 @@ static int do_pci_enable_device(struct pci_dev *dev, int bars) > } > > return 0; > + > +err_enable: > + pci_host_bridge_disable_device(dev); > + > + return err; > + > } > > /** > @@ -2270,6 +2302,8 @@ void pci_disable_device(struct pci_dev *dev) > if (atomic_dec_return(&dev->enable_cnt) != 0) > return; > > + pci_host_bridge_disable_device(dev); > + > do_pci_disable_device(dev); > > dev->is_busmaster = 0; > diff --git a/include/linux/pci.h b/include/linux/pci.h > index a17edc6c28fda..5f75c30f263be 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -596,6 +596,8 @@ struct pci_host_bridge { > u8 (*swizzle_irq)(struct pci_dev *, u8 *); /* Platform IRQ swizzler */ > int (*map_irq)(const struct pci_dev *, u8, u8); > void (*release_fn)(struct pci_host_bridge *); > + int (*enable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev); > + void (*disable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev); > void *release_data; > unsigned int ignore_reset_delay:1; /* For entire hierarchy */ > unsigned int no_ext_tags:1; /* No Extended Tags */ > > -- > 2.34.1 >
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 67013df89a694..4735bc665ab3b 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2055,6 +2055,28 @@ int __weak pcibios_enable_device(struct pci_dev *dev, int bars) return pci_enable_resources(dev, bars); } +static int pci_host_bridge_enable_device(struct pci_dev *dev) +{ + struct pci_host_bridge *host_bridge = pci_find_host_bridge(dev->bus); + int err; + + if (host_bridge && host_bridge->enable_device) { + err = host_bridge->enable_device(host_bridge, dev); + if (err) + return err; + } + + return 0; +} + +static void pci_host_bridge_disable_device(struct pci_dev *dev) +{ + struct pci_host_bridge *host_bridge = pci_find_host_bridge(dev->bus); + + if (host_bridge && host_bridge->disable_device) + host_bridge->disable_device(host_bridge, dev); +} + static int do_pci_enable_device(struct pci_dev *dev, int bars) { int err; @@ -2070,9 +2092,13 @@ static int do_pci_enable_device(struct pci_dev *dev, int bars) if (bridge) pcie_aspm_powersave_config_link(bridge); + err = pci_host_bridge_enable_device(dev); + if (err) + return err; + err = pcibios_enable_device(dev, bars); if (err < 0) - return err; + goto err_enable; pci_fixup_device(pci_fixup_enable, dev); if (dev->msi_enabled || dev->msix_enabled) @@ -2087,6 +2113,12 @@ static int do_pci_enable_device(struct pci_dev *dev, int bars) } return 0; + +err_enable: + pci_host_bridge_disable_device(dev); + + return err; + } /** @@ -2270,6 +2302,8 @@ void pci_disable_device(struct pci_dev *dev) if (atomic_dec_return(&dev->enable_cnt) != 0) return; + pci_host_bridge_disable_device(dev); + do_pci_disable_device(dev); dev->is_busmaster = 0; diff --git a/include/linux/pci.h b/include/linux/pci.h index a17edc6c28fda..5f75c30f263be 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -596,6 +596,8 @@ struct pci_host_bridge { u8 (*swizzle_irq)(struct pci_dev *, u8 *); /* Platform IRQ swizzler */ int (*map_irq)(const struct pci_dev *, u8, u8); void (*release_fn)(struct pci_host_bridge *); + int (*enable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev); + void (*disable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev); void *release_data; unsigned int ignore_reset_delay:1; /* For entire hierarchy */ unsigned int no_ext_tags:1; /* No Extended Tags */