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author | Randy Dunlap <randy.dunlap@oracle.com> | 2008-03-11 03:16:32 +0300 |
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committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-04-21 08:46:51 +0400 |
commit | 4b5ff469234b8ab5cd05f4a201cbb229896729d0 (patch) | |
tree | dc44c4e82be76ffc00cb981eb4606276fffa7e1e /Documentation/PCIEBUS-HOWTO.txt | |
parent | 3925e6fc1f774048404fdd910b0345b06c699eb4 (diff) | |
download | linux-4b5ff469234b8ab5cd05f4a201cbb229896729d0.tar.xz |
PCI: doc/pci: create Documentation/PCI/ and move files into it
Create Documentation/PCI/ and move PCI-related files to it.
Fix a few instances of trailing whitespace.
Update references to the new file locations.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'Documentation/PCIEBUS-HOWTO.txt')
-rw-r--r-- | Documentation/PCIEBUS-HOWTO.txt | 217 |
1 files changed, 0 insertions, 217 deletions
diff --git a/Documentation/PCIEBUS-HOWTO.txt b/Documentation/PCIEBUS-HOWTO.txt deleted file mode 100644 index c93f42a74d7e..000000000000 --- a/Documentation/PCIEBUS-HOWTO.txt +++ /dev/null @@ -1,217 +0,0 @@ - The PCI Express Port Bus Driver Guide HOWTO - Tom L Nguyen tom.l.nguyen@intel.com - 11/03/2004 - -1. About this guide - -This guide describes the basics of the PCI Express Port Bus driver -and provides information on how to enable the service drivers to -register/unregister with the PCI Express Port Bus Driver. - -2. Copyright 2004 Intel Corporation - -3. What is the PCI Express Port Bus Driver - -A PCI Express Port is a logical PCI-PCI Bridge structure. There -are two types of PCI Express Port: the Root Port and the Switch -Port. The Root Port originates a PCI Express link from a PCI Express -Root Complex and the Switch Port connects PCI Express links to -internal logical PCI buses. The Switch Port, which has its secondary -bus representing the switch's internal routing logic, is called the -switch's Upstream Port. The switch's Downstream Port is bridging from -switch's internal routing bus to a bus representing the downstream -PCI Express link from the PCI Express Switch. - -A PCI Express Port can provide up to four distinct functions, -referred to in this document as services, depending on its port type. -PCI Express Port's services include native hotplug support (HP), -power management event support (PME), advanced error reporting -support (AER), and virtual channel support (VC). These services may -be handled by a single complex driver or be individually distributed -and handled by corresponding service drivers. - -4. Why use the PCI Express Port Bus Driver? - -In existing Linux kernels, the Linux Device Driver Model allows a -physical device to be handled by only a single driver. The PCI -Express Port is a PCI-PCI Bridge device with multiple distinct -services. To maintain a clean and simple solution each service -may have its own software service driver. In this case several -service drivers will compete for a single PCI-PCI Bridge device. -For example, if the PCI Express Root Port native hotplug service -driver is loaded first, it claims a PCI-PCI Bridge Root Port. The -kernel therefore does not load other service drivers for that Root -Port. In other words, it is impossible to have multiple service -drivers load and run on a PCI-PCI Bridge device simultaneously -using the current driver model. - -To enable multiple service drivers running simultaneously requires -having a PCI Express Port Bus driver, which manages all populated -PCI Express Ports and distributes all provided service requests -to the corresponding service drivers as required. Some key -advantages of using the PCI Express Port Bus driver are listed below: - - - Allow multiple service drivers to run simultaneously on - a PCI-PCI Bridge Port device. - - - Allow service drivers implemented in an independent - staged approach. - - - Allow one service driver to run on multiple PCI-PCI Bridge - Port devices. - - - Manage and distribute resources of a PCI-PCI Bridge Port - device to requested service drivers. - -5. Configuring the PCI Express Port Bus Driver vs. Service Drivers - -5.1 Including the PCI Express Port Bus Driver Support into the Kernel - -Including the PCI Express Port Bus driver depends on whether the PCI -Express support is included in the kernel config. The kernel will -automatically include the PCI Express Port Bus driver as a kernel -driver when the PCI Express support is enabled in the kernel. - -5.2 Enabling Service Driver Support - -PCI device drivers are implemented based on Linux Device Driver Model. -All service drivers are PCI device drivers. As discussed above, it is -impossible to load any service driver once the kernel has loaded the -PCI Express Port Bus Driver. To meet the PCI Express Port Bus Driver -Model requires some minimal changes on existing service drivers that -imposes no impact on the functionality of existing service drivers. - -A service driver is required to use the two APIs shown below to -register its service with the PCI Express Port Bus driver (see -section 5.2.1 & 5.2.2). It is important that a service driver -initializes the pcie_port_service_driver data structure, included in -header file /include/linux/pcieport_if.h, before calling these APIs. -Failure to do so will result an identity mismatch, which prevents -the PCI Express Port Bus driver from loading a service driver. - -5.2.1 pcie_port_service_register - -int pcie_port_service_register(struct pcie_port_service_driver *new) - -This API replaces the Linux Driver Model's pci_module_init API. A -service driver should always calls pcie_port_service_register at -module init. Note that after service driver being loaded, calls -such as pci_enable_device(dev) and pci_set_master(dev) are no longer -necessary since these calls are executed by the PCI Port Bus driver. - -5.2.2 pcie_port_service_unregister - -void pcie_port_service_unregister(struct pcie_port_service_driver *new) - -pcie_port_service_unregister replaces the Linux Driver Model's -pci_unregister_driver. It's always called by service driver when a -module exits. - -5.2.3 Sample Code - -Below is sample service driver code to initialize the port service -driver data structure. - -static struct pcie_port_service_id service_id[] = { { - .vendor = PCI_ANY_ID, - .device = PCI_ANY_ID, - .port_type = PCIE_RC_PORT, - .service_type = PCIE_PORT_SERVICE_AER, - }, { /* end: all zeroes */ } -}; - -static struct pcie_port_service_driver root_aerdrv = { - .name = (char *)device_name, - .id_table = &service_id[0], - - .probe = aerdrv_load, - .remove = aerdrv_unload, - - .suspend = aerdrv_suspend, - .resume = aerdrv_resume, -}; - -Below is a sample code for registering/unregistering a service -driver. - -static int __init aerdrv_service_init(void) -{ - int retval = 0; - - retval = pcie_port_service_register(&root_aerdrv); - if (!retval) { - /* - * FIX ME - */ - } - return retval; -} - -static void __exit aerdrv_service_exit(void) -{ - pcie_port_service_unregister(&root_aerdrv); -} - -module_init(aerdrv_service_init); -module_exit(aerdrv_service_exit); - -6. Possible Resource Conflicts - -Since all service drivers of a PCI-PCI Bridge Port device are -allowed to run simultaneously, below lists a few of possible resource -conflicts with proposed solutions. - -6.1 MSI Vector Resource - -The MSI capability structure enables a device software driver to call -pci_enable_msi to request MSI based interrupts. Once MSI interrupts -are enabled on a device, it stays in this mode until a device driver -calls pci_disable_msi to disable MSI interrupts and revert back to -INTx emulation mode. Since service drivers of the same PCI-PCI Bridge -port share the same physical device, if an individual service driver -calls pci_enable_msi/pci_disable_msi it may result unpredictable -behavior. For example, two service drivers run simultaneously on the -same physical Root Port. Both service drivers call pci_enable_msi to -request MSI based interrupts. A service driver may not know whether -any other service drivers have run on this Root Port. If either one -of them calls pci_disable_msi, it puts the other service driver -in a wrong interrupt mode. - -To avoid this situation all service drivers are not permitted to -switch interrupt mode on its device. The PCI Express Port Bus driver -is responsible for determining the interrupt mode and this should be -transparent to service drivers. Service drivers need to know only -the vector IRQ assigned to the field irq of struct pcie_device, which -is passed in when the PCI Express Port Bus driver probes each service -driver. Service drivers should use (struct pcie_device*)dev->irq to -call request_irq/free_irq. In addition, the interrupt mode is stored -in the field interrupt_mode of struct pcie_device. - -6.2 MSI-X Vector Resources - -Similar to the MSI a device driver for an MSI-X capable device can -call pci_enable_msix to request MSI-X interrupts. All service drivers -are not permitted to switch interrupt mode on its device. The PCI -Express Port Bus driver is responsible for determining the interrupt -mode and this should be transparent to service drivers. Any attempt -by service driver to call pci_enable_msix/pci_disable_msix may -result unpredictable behavior. Service drivers should use -(struct pcie_device*)dev->irq and call request_irq/free_irq. - -6.3 PCI Memory/IO Mapped Regions - -Service drivers for PCI Express Power Management (PME), Advanced -Error Reporting (AER), Hot-Plug (HP) and Virtual Channel (VC) access -PCI configuration space on the PCI Express port. In all cases the -registers accessed are independent of each other. This patch assumes -that all service drivers will be well behaved and not overwrite -other service driver's configuration settings. - -6.4 PCI Config Registers - -Each service driver runs its PCI config operations on its own -capability structure except the PCI Express capability structure, in -which Root Control register and Device Control register are shared -between PME and AER. This patch assumes that all service drivers -will be well behaved and not overwrite other service driver's -configuration settings. |