On Tue, Feb 4, 2014 at 10:23 PM, Will Deacon <will.deacon@xxxxxxx> wrote: > This patch adds support for an extremely simple virtual PCI host > controller. The controller itself has no configuration registers, and > has its address spaces described entirely by the device-tree (using the > bindings described by ePAPR). This allows emulations, such as kvmtool, > to provide a simple means for a guest Linux instance to make use of > PCI devices. > > Corresponding documentation is added for the DT binding. > > Signed-off-by: Will Deacon <will.deacon@xxxxxxx> > --- > .../devicetree/bindings/pci/linux,pci-virt.txt | 38 ++++ > drivers/pci/host/Kconfig | 7 + > drivers/pci/host/Makefile | 1 + > drivers/pci/host/pci-virt.c | 200 +++++++++++++++++++++ > 4 files changed, 246 insertions(+) > create mode 100644 Documentation/devicetree/bindings/pci/linux,pci-virt.txt > create mode 100644 drivers/pci/host/pci-virt.c > > diff --git a/Documentation/devicetree/bindings/pci/linux,pci-virt.txt b/Documentation/devicetree/bindings/pci/linux,pci-virt.txt > new file mode 100644 > index 000000000000..54668a283498 > --- /dev/null > +++ b/Documentation/devicetree/bindings/pci/linux,pci-virt.txt > @@ -0,0 +1,38 @@ > +* ARM Basic Virtual PCI controller > + > +PCI emulations, such as the virtio-pci implementations found in kvmtool > +and other para-virtualised systems, do not require driver support for > +complexities such as regulator and clock management. In fact, the > +controller may not even have a control interface visible to the > +operating system, instead presenting a set of fixed windows describing a > +subset of IO, Memory and Configuration spaces. > + > +Such a controller can be described purely in terms of the standardized > +device tree bindings communicated in pci.txt: > + > +- compatible : Must be "linux,pci-virt" > + > +- ranges : As described in IEEE Std 1275-1994, but must provide > + at least a definition of the Configuration Space plus > + one or both of IO and Memory Space. > + > +- #address-cells : Must be 3 > + > +- #size-cells : Must be 2 > + > +Configuration Space is assumed to be memory-mapped (as opposed to being It would be great to have a flag to specify whether Configuration Space is over ioports or memory mapped. Regards, Anup > +accessed via an ioport) and laid out with a direct correspondence to the > +geography of a PCI bus address, by concatenating the various components > +to form a 24-bit offset: > + > + cfg_offset(bus, device, function, register) = > + bus << 16 | device << 11 | function << 8 | register > + > +Interrupt mapping is exactly as described in `Open Firmware Recommended > +Practice: Interrupt Mapping' and requires the following properties: > + > +- #interrupt-cells : Must be 1 > + > +- interrupt-map : <see aforementioned specification> > + > +- interrupt-map-mask : <see aforementioned specification> > diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig > index 47d46c6d8468..fd4460573b81 100644 > --- a/drivers/pci/host/Kconfig > +++ b/drivers/pci/host/Kconfig > @@ -33,4 +33,11 @@ config PCI_RCAR_GEN2 > There are 3 internal PCI controllers available with a single > built-in EHCI/OHCI host controller present on each one. > > +config PCI_VIRT_HOST > + bool "Virtual PCI host controller" > + depends on ARM && OF > + help > + Say Y here if you want to support a very simple virtual PCI > + host controller, such as the one emulated by kvmtool. > + > endmenu > diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile > index 13fb3333aa05..9b6775d95d3b 100644 > --- a/drivers/pci/host/Makefile > +++ b/drivers/pci/host/Makefile > @@ -4,3 +4,4 @@ obj-$(CONFIG_PCI_IMX6) += pci-imx6.o > obj-$(CONFIG_PCI_MVEBU) += pci-mvebu.o > obj-$(CONFIG_PCI_TEGRA) += pci-tegra.o > obj-$(CONFIG_PCI_RCAR_GEN2) += pci-rcar-gen2.o > +obj-$(CONFIG_PCI_VIRT_HOST) += pci-virt.o > diff --git a/drivers/pci/host/pci-virt.c b/drivers/pci/host/pci-virt.c > new file mode 100644 > index 000000000000..ded01474453b > --- /dev/null > +++ b/drivers/pci/host/pci-virt.c > @@ -0,0 +1,200 @@ > +/* > + * Very basic PCI host controller driver targetting virtual machines > + * (e.g. the PCI emulation provided by kvmtool). > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program. If not, see <http://www.gnu.org/licenses/>. > + * > + * Copyright (C) 2014 ARM Limited > + * > + * Author: Will Deacon <will.deacon@xxxxxxx> > + * > + * This driver currently supports (per instance): > + * - A single controller > + * - A single memory space and/or port space > + * - A memory-mapped configuration space > + */ > + > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/of_address.h> > +#include <linux/of_pci.h> > +#include <linux/platform_device.h> > + > +struct virt_pci { > + struct device *dev; > + > + struct resource cfg; > + struct resource io; > + struct resource mem; > + > + void __iomem *cfg_base; > +}; > + > +static void __iomem *virt_pci_config_address(struct pci_bus *bus, > + unsigned int devfn, > + int where) > +{ > + struct pci_sys_data *sys = bus->sysdata; > + struct virt_pci *pci = sys->private_data; > + void __iomem *addr = pci->cfg_base; > + > + /* > + * We construct config space addresses by simply sandwiching > + * together all of the PCI address components and using the > + * result as an offset into a 16M region. > + */ > + return addr + (((u32)bus->number << 16) | (devfn << 8) | where); > +} > + > + > +static int virt_pci_config_read(struct pci_bus *bus, unsigned int devfn, > + int where, int size, u32 *val) > +{ > + void __iomem *addr = virt_pci_config_address(bus, devfn, where); > + > + switch (size) { > + case 1: > + *val = readb(addr); > + break; > + case 2: > + *val = readw(addr); > + break; > + default: > + *val = readl(addr); > + } > + > + return PCIBIOS_SUCCESSFUL; > +} > + > +static int virt_pci_config_write(struct pci_bus *bus, unsigned int devfn, > + int where, int size, u32 val) > +{ > + void __iomem *addr = virt_pci_config_address(bus, devfn, where); > + > + switch (size) { > + case 1: > + writeb(val, addr); > + break; > + case 2: > + writew(val, addr); > + break; > + default: > + writel(val, addr); > + } > + > + return PCIBIOS_SUCCESSFUL; > +} > + > +static struct pci_ops virt_pci_ops = { > + .read = virt_pci_config_read, > + .write = virt_pci_config_write, > +}; > + > +static int virt_pci_setup(int nr, struct pci_sys_data *sys) > +{ > + struct virt_pci *pci = sys->private_data; > + > + if (resource_type(&pci->io)) { > + pci_add_resource(&sys->resources, &pci->io); > + pci_ioremap_io(nr * resource_size(&pci->io), pci->io.start); > + } > + > + if (resource_type(&pci->mem)) > + pci_add_resource(&sys->resources, &pci->mem); > + > + pci->cfg_base = devm_ioremap_resource(pci->dev, &pci->cfg); > + return !IS_ERR(pci->cfg_base); > +} > + > +static const struct of_device_id virt_pci_of_match[] = { > + { .compatible = "linux,pci-virt" }, > + { }, > +}; > +MODULE_DEVICE_TABLE(of, virt_pci_of_match); > + > +static int virt_pci_probe(struct platform_device *pdev) > +{ > + struct hw_pci hw; > + struct of_pci_range range; > + struct of_pci_range_parser parser; > + struct virt_pci *pci; > + struct device *dev = &pdev->dev; > + struct device_node *np = dev->of_node; > + > + if (of_pci_range_parser_init(&parser, np)) { > + dev_err(dev, "missing \"ranges\" property\n"); > + return -EINVAL; > + } > + > + pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL); > + if (!pci) > + return -ENOMEM; > + > + pci->dev = dev; > + for_each_of_pci_range(&parser, &range) { > + u32 restype = range.flags & IORESOURCE_TYPE_BITS; > + > + switch (restype) { > + case IORESOURCE_IO: > + if (resource_type(&pci->io)) > + dev_warn(dev, > + "ignoring additional io resource\n"); > + else > + of_pci_range_to_resource(&range, np, &pci->io); > + break; > + case IORESOURCE_MEM: > + if (resource_type(&pci->mem)) > + dev_warn(dev, > + "ignoring additional mem resource\n"); > + else > + of_pci_range_to_resource(&range, np, &pci->mem); > + break; > + case 0: /* cfg */ > + if (resource_type(&pci->cfg)) { > + dev_warn(dev, > + "ignoring additional cfg resource\n"); > + } else { > + of_pci_range_to_resource(&range, np, &pci->cfg); > + pci->cfg.flags |= IORESOURCE_MEM; > + } > + break; > + default: > + dev_warn(dev, > + "ignoring unknown/unsupported resource type %x\n", > + restype); > + } > + } > + > + memset(&hw, 0, sizeof(hw)); > + hw.nr_controllers = 1; > + hw.private_data = (void **)&pci; > + hw.setup = virt_pci_setup; > + hw.map_irq = of_irq_parse_and_map_pci; > + hw.ops = &virt_pci_ops; > + pci_common_init_dev(dev, &hw); > + return 0; > +} > + > +static struct platform_driver virt_pci_driver = { > + .driver = { > + .name = "pci-virt", > + .owner = THIS_MODULE, > + .of_match_table = virt_pci_of_match, > + }, > + .probe = virt_pci_probe, > +}; > +module_platform_driver(virt_pci_driver); > + > +MODULE_DESCRIPTION("Virtual PCI host driver"); > +MODULE_AUTHOR("Will Deacon <will.deacon@xxxxxxx>"); > +MODULE_LICENSE("GPLv2"); > -- > 1.8.2.2 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
