+++ /dev/null
- 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_register_driver 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 and MSI-X Vector Resource
-
-Once MSI or MSI-X interrupts are enabled on a device, it stays in this
-mode until they are disabled again. Since service drivers of the same
-PCI-PCI Bridge port share the same physical device, if an individual
-service driver enables or disables MSI/MSI-X mode it may result
-unpredictable behavior.
-
-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.
-
-6.3 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.
--- /dev/null
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
+===========================================
+The PCI Express Port Bus Driver Guide HOWTO
+===========================================
+
+:Author: Tom L Nguyen tom.l.nguyen@intel.com 11/03/2004
+:Copyright: |copy| 2004 Intel Corporation
+
+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.
+
+
+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.
+
+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.
+
+Configuring the PCI Express Port Bus Driver vs. Service Drivers
+===============================================================
+
+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.
+
+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.
+
+pcie_port_service_register
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+::
+
+ int pcie_port_service_register(struct pcie_port_service_driver *new)
+
+This API replaces the Linux Driver Model's pci_register_driver 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.
+
+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.
+
+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);
+
+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.
+
+MSI and MSI-X Vector Resource
+-----------------------------
+
+Once MSI or MSI-X interrupts are enabled on a device, it stays in this
+mode until they are disabled again. Since service drivers of the same
+PCI-PCI Bridge port share the same physical device, if an individual
+service driver enables or disables MSI/MSI-X mode it may result
+unpredictable behavior.
+
+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.
+
+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.
+
+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.
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