| Message ID | 1448282426-2642-2-git-send-email-thierry.reding@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Mon, Nov 23, 2015 at 01:40:26PM +0100, Thierry Reding wrote: > From: Thierry Reding <treding@nvidia.com> > > The configuration space mapping on Tegra is somewhat special, and in It'd be nice to have a tiny hint about specifically what is special about Tegra config space mapping. > order to avoid wasting virtual address space the configuration space > for each bus needs to be stitched together from several blocks which > form a single continuous virtual address range for accessors. > > Currently the configuration space is mapped upon the first access to > one of its registers. However, the mapping operation may sleep under > certain circumstances, so doing it from the configuration space > accessors (they are protected by a spin lock) will trigger a warning. Can you include the exact warning? Does it happen always? Always on the first config access to a bus? > To avoid the warning, use the ->add_bus() callback to perform the > mapping at enumeration time when the operation is allowed to sleep. > > Signed-off-by: Thierry Reding <treding@nvidia.com> > --- > drivers/pci/host/pci-tegra.c | 40 +++++++++++++++++++--------------------- > 1 file changed, 19 insertions(+), 21 deletions(-) > > diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c > index 3018ae52e092..c3666f9d7ef1 100644 > --- a/drivers/pci/host/pci-tegra.c > +++ b/drivers/pci/host/pci-tegra.c > @@ -426,31 +426,23 @@ free: > return ERR_PTR(err); > } > > -/* > - * Look up a virtual address mapping for the specified bus number. If no such > - * mapping exists, try to create one. > - */ > -static void __iomem *tegra_pcie_bus_map(struct tegra_pcie *pcie, > - unsigned int busnr) > +static int tegra_pcie_add_bus(struct pci_bus *bus) > { > - struct tegra_pcie_bus *bus; > + struct tegra_pcie *pcie = sys_to_pcie(bus->sysdata); > + struct tegra_pcie_bus *b; > > - list_for_each_entry(bus, &pcie->buses, list) > - if (bus->nr == busnr) > - return (void __iomem *)bus->area->addr; > + b = tegra_pcie_bus_alloc(pcie, bus->number); > + if (IS_ERR(b)) > + return PTR_ERR(b); > > - bus = tegra_pcie_bus_alloc(pcie, busnr); > - if (IS_ERR(bus)) > - return NULL; > + list_add_tail(&b->list, &pcie->buses); > > - list_add_tail(&bus->list, &pcie->buses); > - > - return (void __iomem *)bus->area->addr; > + return 0; > } > > -static void __iomem *tegra_pcie_conf_address(struct pci_bus *bus, > - unsigned int devfn, > - int where) > +static void __iomem *tegra_pcie_map_bus(struct pci_bus *bus, > + unsigned int devfn, > + int where) > { > struct tegra_pcie *pcie = sys_to_pcie(bus->sysdata); > void __iomem *addr = NULL; > @@ -466,7 +458,12 @@ static void __iomem *tegra_pcie_conf_address(struct pci_bus *bus, > } > } > } else { > - addr = tegra_pcie_bus_map(pcie, bus->number); > + struct tegra_pcie_bus *b; > + > + list_for_each_entry(b, &pcie->buses, list) > + if (b->nr == bus->number) > + addr = (void __iomem *)b->area->addr; > + > if (!addr) { > dev_err(pcie->dev, > "failed to map cfg. space for bus %u\n", > @@ -481,7 +478,8 @@ static void __iomem *tegra_pcie_conf_address(struct pci_bus *bus, > } > > static struct pci_ops tegra_pcie_ops = { > - .map_bus = tegra_pcie_conf_address, > + .add_bus = tegra_pcie_add_bus, > + .map_bus = tegra_pcie_map_bus, > .read = pci_generic_config_read32, > .write = pci_generic_config_write32, > }; > -- > 2.5.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c index 3018ae52e092..c3666f9d7ef1 100644 --- a/drivers/pci/host/pci-tegra.c +++ b/drivers/pci/host/pci-tegra.c @@ -426,31 +426,23 @@ free: return ERR_PTR(err); } -/* - * Look up a virtual address mapping for the specified bus number. If no such - * mapping exists, try to create one. - */ -static void __iomem *tegra_pcie_bus_map(struct tegra_pcie *pcie, - unsigned int busnr) +static int tegra_pcie_add_bus(struct pci_bus *bus) { - struct tegra_pcie_bus *bus; + struct tegra_pcie *pcie = sys_to_pcie(bus->sysdata); + struct tegra_pcie_bus *b; - list_for_each_entry(bus, &pcie->buses, list) - if (bus->nr == busnr) - return (void __iomem *)bus->area->addr; + b = tegra_pcie_bus_alloc(pcie, bus->number); + if (IS_ERR(b)) + return PTR_ERR(b); - bus = tegra_pcie_bus_alloc(pcie, busnr); - if (IS_ERR(bus)) - return NULL; + list_add_tail(&b->list, &pcie->buses); - list_add_tail(&bus->list, &pcie->buses); - - return (void __iomem *)bus->area->addr; + return 0; } -static void __iomem *tegra_pcie_conf_address(struct pci_bus *bus, - unsigned int devfn, - int where) +static void __iomem *tegra_pcie_map_bus(struct pci_bus *bus, + unsigned int devfn, + int where) { struct tegra_pcie *pcie = sys_to_pcie(bus->sysdata); void __iomem *addr = NULL; @@ -466,7 +458,12 @@ static void __iomem *tegra_pcie_conf_address(struct pci_bus *bus, } } } else { - addr = tegra_pcie_bus_map(pcie, bus->number); + struct tegra_pcie_bus *b; + + list_for_each_entry(b, &pcie->buses, list) + if (b->nr == bus->number) + addr = (void __iomem *)b->area->addr; + if (!addr) { dev_err(pcie->dev, "failed to map cfg. space for bus %u\n", @@ -481,7 +478,8 @@ static void __iomem *tegra_pcie_conf_address(struct pci_bus *bus, } static struct pci_ops tegra_pcie_ops = { - .map_bus = tegra_pcie_conf_address, + .add_bus = tegra_pcie_add_bus, + .map_bus = tegra_pcie_map_bus, .read = pci_generic_config_read32, .write = pci_generic_config_write32, };