diff options
Diffstat (limited to 'doc/driver-model/pci-info.rst')
| -rw-r--r-- | doc/driver-model/pci-info.rst | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/doc/driver-model/pci-info.rst b/doc/driver-model/pci-info.rst index d93ab8b61d..3c1b1adf07 100644 --- a/doc/driver-model/pci-info.rst +++ b/doc/driver-model/pci-info.rst @@ -103,7 +103,7 @@ in each of these nodes. If PCI devices are not listed in the device tree, U_BOOT_PCI_DEVICE can be used to specify the driver to use for the device. The device tree takes precedence -over U_BOOT_PCI_DEVICE. Plese note with U_BOOT_PCI_DEVICE, only drivers with +over U_BOOT_PCI_DEVICE. Please note with U_BOOT_PCI_DEVICE, only drivers with DM_FLAG_PRE_RELOC will be bound before relocation. If neither device tree nor U_BOOT_PCI_DEVICE is provided, the built-in driver (either pci_bridge_drv or pci_generic_drv) will be used. @@ -113,14 +113,17 @@ Sandbox ------- With sandbox we need a device emulator for each device on the bus since there -is no real PCI bus. This works by looking in the device tree node for a -driver. For example:: - +is no real PCI bus. This works by looking in the device tree node for an +emulator driver. For example:: pci@1f,0 { compatible = "pci-generic"; reg = <0xf800 0 0 0 0>; - emul@1f,0 { + sandbox,emul = <&emul_1f>; + }; + pci-emul { + compatible = "sandbox,pci-emul-parent"; + emul_1f: emul@1f,0 { compatible = "sandbox,swap-case"; }; }; @@ -130,14 +133,16 @@ Note that the first cell in the 'reg' value is the bus/device/function. See PCI_BDF() for the encoding (it is also specified in the IEEE Std 1275-1994 PCI bus binding document, v2.1) +The pci-emul node should go outside the pci bus node, since otherwise it will +be scanned as a PCI device, causing confusion. + When this bus is scanned we will end up with something like this:: `- * pci-controller @ 05c660c8, 0 `- pci@1f,0 @ 05c661c8, 63488 - `- emul@1f,0 @ 05c662c8 + `- emul@1f,0 @ 05c662c8 -When accesses go to the pci@1f,0 device they are forwarded to its child, the -emulator. +When accesses go to the pci@1f,0 device they are forwarded to its emulator. The sandbox PCI drivers also support dynamic driver binding, allowing device driver to declare the driver binding information via U_BOOT_PCI_DEVICE(), @@ -164,7 +169,3 @@ When this bus is scanned we will end up with something like this:: pci [ + ] pci_sandbo |-- pci-controller1 pci_emul [ ] sandbox_sw | |-- sandbox_swap_case_emul pci_emul [ ] sandbox_sw | `-- sandbox_swap_case_emul - -Note the difference from the statically declared device nodes is that the -device is directly attached to the host controller, instead of via a container -device like pci@1f,0. |