From patchwork Thu Jan 12 10:26:04 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kishon Vijay Abraham I X-Patchwork-Id: 9512919 X-Patchwork-Delegate: agross@codeaurora.org Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id D6CD2607D2 for ; Thu, 12 Jan 2017 10:47:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C7CEA286B9 for ; Thu, 12 Jan 2017 10:47:11 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BCAFB2868C; Thu, 12 Jan 2017 10:47:11 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 30511286EF for ; Thu, 12 Jan 2017 10:47:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751341AbdALKji (ORCPT ); Thu, 12 Jan 2017 05:39:38 -0500 Received: from fllnx210.ext.ti.com ([198.47.19.17]:55835 "EHLO fllnx210.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751381AbdALK3C (ORCPT ); Thu, 12 Jan 2017 05:29:02 -0500 Received: from dflxv15.itg.ti.com ([128.247.5.124]) by fllnx210.ext.ti.com (8.15.1/8.15.1) with ESMTP id v0CASJ99016657; Thu, 12 Jan 2017 04:28:19 -0600 Received: from DFLE72.ent.ti.com (dfle72.ent.ti.com [128.247.5.109]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id v0CASJlc024826; Thu, 12 Jan 2017 04:28:19 -0600 Received: from dflp32.itg.ti.com (10.64.6.15) by DFLE72.ent.ti.com (128.247.5.109) with Microsoft SMTP Server id 14.3.294.0; Thu, 12 Jan 2017 04:28:18 -0600 Received: from a0393678ub.india.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by dflp32.itg.ti.com (8.14.3/8.13.8) with ESMTP id v0CAQpCQ016300; Thu, 12 Jan 2017 04:28:14 -0600 From: Kishon Vijay Abraham I To: Bjorn Helgaas , Jingoo Han , Joao Pinto , Arnd Bergmann CC: , , , , , , , , , , , Subject: [PATCH 15/37] Documentation: PCI: Guide to use PCI Endpoint Core Layer Date: Thu, 12 Jan 2017 15:56:04 +0530 Message-ID: <1484216786-17292-16-git-send-email-kishon@ti.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1484216786-17292-1-git-send-email-kishon@ti.com> References: <1484216786-17292-1-git-send-email-kishon@ti.com> MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add Documentation to help users use endpoint library to enable endpoint mode in the PCI controller and add new PCI endpoint functions. Signed-off-by: Kishon Vijay Abraham I --- Documentation/PCI/00-INDEX | 2 + Documentation/PCI/endpoint/pci-endpoint.txt | 190 +++++++++++++++++++++++++++ 2 files changed, 192 insertions(+) create mode 100644 Documentation/PCI/endpoint/pci-endpoint.txt diff --git a/Documentation/PCI/00-INDEX b/Documentation/PCI/00-INDEX index 147231f..ba950b2 100644 --- a/Documentation/PCI/00-INDEX +++ b/Documentation/PCI/00-INDEX @@ -12,3 +12,5 @@ pci.txt - info on the PCI subsystem for device driver authors pcieaer-howto.txt - the PCI Express Advanced Error Reporting Driver Guide HOWTO +endpoint/pci-endpoint.txt + - guide to add endpoint controller driver and endpoint function driver. diff --git a/Documentation/PCI/endpoint/pci-endpoint.txt b/Documentation/PCI/endpoint/pci-endpoint.txt new file mode 100644 index 0000000..68a7839 --- /dev/null +++ b/Documentation/PCI/endpoint/pci-endpoint.txt @@ -0,0 +1,190 @@ + PCI ENDPOINT FRAMEWORK + Kishon Vijay Abraham I + +This document is a guide to use the PCI Endpoint Framework in order to create +endpoint controller driver, endpoint function driver and using configfs +interface to bind the function driver to the controller driver. + +1. Introduction + +*Linux* has a comprehensive PCI subsystem to support PCI controllers that +operates in Root Complex mode. The subsystem has capability to scan PCI bus, +assign memory resources and irq resources, load PCI driver (based on +vendorid, deviceid), support other services like hot-plug, power management, +advanced error reporting and virtual channels. + +However PCI controller IPs integrated in certain SoC is capable of operating +either in Root Complex mode or Endpoint mode. PCI Endpoint Framework will +add endpoint mode support in *Linux*. This will help to run Linux in an +EP system which can have a wide variety of use cases from testing or +validation, co-processor accelerator etc.. + +2. PCI Endpoint Core + +The PCI Endpoint Core layer comprises of 3 components: the Endpoint Controller +library, the Endpoint Function library and the configfs layer to bind the +endpoint function with the endpoint controller. + +2.1 PCI Endpoint Controller(EPC) Library + +The EPC library provides APIs to be used by the controller that can operate +in endpoint mode. It also provides APIs to be used by function driver/library +in order to implement a particular endpoint function. + +2.1.1 APIs for the PCI controller Driver + +This section lists the APIs that the PCI Endpoint core provides to be used +by the PCI controller driver. + +*) devm_pci_epc_create()/pci_epc_create() + + The PCI controller driver should implement the following ops: + * write_header: ops to populate configuration space header + * set_bar: ops to configure the BAR + * clear_bar: ops to reset the BAR + * alloc_addr_space: ops to allocate *in* PCI controller address space + * free_addr_space: ops to free the allocated address space + * raise_irq: ops to raise a legacy or MSI interrupt + * start: ops to start the PCI link + * stop: ops to stop the PCI link + + The PCI controller driver can then create a new EPC device by invoking + devm_pci_epc_create/pci_epc_create. + +*) devm_pci_epc_destroy()/pci_epc_destroy() + + The PCI controller driver can destroy the EPC device created by either + devm_pci_epc_create or pci_epc_create using devm_pci_epc_destroy() or + /pci_epc_destroy() + +2.1.2 APIs for the PCI Endpoint Function Driver + +This section lists the APIs that the PCI Endpoint core provides to be used +by the PCI endpoint function driver. + +*) pci_epc_write_header() + + The PCI endpoint function driver should use pci_epc_write_header() to + write the standard configuration header to the endpoint controller. + +*) pci_epc_set_bar() + + The PCI endpoint function driver should use pci_epc_set_bar() to configure + the Base Address Register in order for the host to assign PCI addr space. + Register space of the function driver is usually configured + using this API. + +*) pci_epc_clear_bar() + + The PCI endpoint function driver should use pci_epc_clear_bar() to reset + the BAR. + +*) pci_epc_raise_irq() + + The PCI endpoint function driver should use pci_epc_raise_irq() to raise + Legacy Interrupt or MSI Interrupt. + +*) pci_epc_start() + + The PCI endpoint function driver should invoke pci_epc_start() once it + has configured the endpoint function and wants to start the PCI link. + +*) pci_epc_stop() + + The PCI endpoint function driver should invoke pci_epc_stop() to stop + the PCI LINK. + +2.1.3 Other APIs + +There are other APIs provided by the EPC library. These are used for binding +the epf device with epc device. pci-ep-cfs.c can be used as reference for +using these APIs. + +*) pci_epc_get() + + Get a reference to the pci endpoint controller based on the device name of + the controller. + +*) pci_epc_put() + + Release the reference to the pci endpoint controller obtained using + pci_epc_get() + +*) pci_epc_add_epf() + + Add a pci endpoint function to a pci endpoint controller. A pcie device + can have upto 8 functions according to the specification. + +*) pci_epc_remove_epf() + + Remove the pci endpoint function from pci endpoint controller. + +2.2 PCI Endpoint Function(EPF) Library + +The EPF library provides APIs to be used by the function driver and the EPC +library in order to provide endpoint mode functionality. + +2.2.1 APIs for the PCI Endpoint Function Driver + +This section lists the APIs that the PCI Endpoint core provides to be used +by the PCI endpoint function driver. + +*) pci_epf_register_driver() + + The PCI Endpoint Function driver should implement the following ops: + * bind: ops to perform when a EPC device has been bound to EPF device + * unbind: ops to perform when a binding has been lost between a EPC + device and EPF device + * linkup: ops to perform when the EPC device has established a + connection with a host system + + The PCI Function driver can then register the PCI EPF driver by using + pci_epf_register_driver(). + +*) pci_epf_unregister_driver() + + The PCI Function driver can unregister the PCI EPF driver by using + pci_epf_unregister_driver(). + +*) pci_epf_alloc_space() + + The PCI Function driver can allocate space for a particular BAR using + pci_epf_alloc_space(). + +*) pci_epf_free_space() + + The PCI Function driver can free the allocated space + (using pci_epf_alloc_space) by invoking pci_epf_free_space(). + +2.2.2 APIs for the PCI Endpoint Controller Library +This section lists the APIs that the PCI Endpoint core provides to be used +by the PCI endpoint controller library. + +*) pci_epf_linkup() + + The PCI endpoint controller library invokes pci_epf_linkup() when the + EPC device has established the connection to the host. + +2.2.2 Other APIs +There are other APIs provided by the EPF library. These are used to notify +the function driver when the EPF device is bound to the EPC device. +pci-ep-cfs.c can be used as reference for using these APIs. + +*) pci_epf_create() + + Create a new PCI EPF device by passing the name of the PCI EPF device. + This name will be used to bind the the EPF device to a EPF driver. + +*) pci_epf_destroy() + + Destroy the created PCI EPF device. + +*) pci_epf_bind() + + pci_epf_bind() should be invoked when the EPF device has been bound to + a EPC device. + +*) pci_epf_unbind() + + pci_epf_unbind() should be invoked when the binding between EPC device + and EPF device is lost.