From patchwork Thu Jul 6 03:09:41 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Oza Pawandeep X-Patchwork-Id: 784959 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3x32n01F8qz9s72 for ; Thu, 6 Jul 2017 13:10:44 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=broadcom.com header.i=@broadcom.com header.b="hUbl7WTx"; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752694AbdGFDKF (ORCPT ); Wed, 5 Jul 2017 23:10:05 -0400 Received: from mail-wr0-f176.google.com ([209.85.128.176]:35171 "EHLO mail-wr0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752493AbdGFDJ7 (ORCPT ); Wed, 5 Jul 2017 23:09:59 -0400 Received: by mail-wr0-f176.google.com with SMTP id k67so9588218wrc.2 for ; Wed, 05 Jul 2017 20:09:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=jQuC8diQPza8KpGzgrtUWMPrRtPFvto9NrGwOIJcgyI=; b=hUbl7WTxAD1tpNp7ldtDH5JeM5LhySC17ClsY+OaQccjdtuOUmbOViILWsAW/jQQyX CbZdqZcJVjxBEZ8gt2ehft4g161aI5FxPJ65P6VjdXER8oFW0mfH4E9kEtdJUN+oKvj/ T9EQeV3EmGv4g30CUf4LQPK7PijbOusspRlIQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=jQuC8diQPza8KpGzgrtUWMPrRtPFvto9NrGwOIJcgyI=; b=s7fLhE9YgXDVvhZ6PzxZ7NSM+WhJ5Lsw06roAx4WQy4JwoOW2fvynvBjt0q9OddXMZ +L0cWK4TxMh94Wo5Y0lT1Pi1/Z17ohg9wUjinP4FmCtSKDEsN4JbmnT990J0766+sLJ6 0wfrYfG1bUJ9pmqWaWJCI7K6pN6pKzuF9h56pdvR3j8VAXoxvrHz9xwOwvXaFhVFGyGU 67K45Z+9xfUX0yjfzq9MqGvqHDLOm/01z2BRqLdtasFaQK6s1c2v2reKwXnIVwf5WJcA rW1nexUjQoVwtEpue3Th+V4LubKU4T/xUhVllE844soKgHZtSGo7onavBZ/G9T8IgaoL Lq5w== X-Gm-Message-State: AKS2vOziS5ubEKKqSS4xwzHAPwFoSct0mrFYWcCsAWYx4ehZR+ZJ3nUw 0nlW8SuBpGJ2mJxe X-Received: by 10.223.176.253 with SMTP id j58mr38527113wra.65.1499310598109; Wed, 05 Jul 2017 20:09:58 -0700 (PDT) Received: from anjanavk-OptiPlex-7010.dhcp.avagotech.net ([192.19.237.250]) by smtp.gmail.com with ESMTPSA id b94sm664946wrd.40.2017.07.05.20.09.52 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 05 Jul 2017 20:09:57 -0700 (PDT) From: Oza Pawandeep To: Bjorn Helgaas , Ray Jui , Scott Branden , Jon Mason , bcm-kernel-feedback-list@broadcom.com, Oza Pawandeep , Andy Gospodarek , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Oza Pawandeep Subject: [PATCH v5 1/2] PCI: iproc: Retry request when CRS returned from EP Date: Thu, 6 Jul 2017 08:39:41 +0530 Message-Id: <1499310582-21193-2-git-send-email-oza.oza@broadcom.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1499310582-21193-1-git-send-email-oza.oza@broadcom.com> References: <1499310582-21193-1-git-send-email-oza.oza@broadcom.com> MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org For Configuration Requests only, following reset it is possible for a device to terminate the request but indicate that it is temporarily unable to process the Request, but will be able to process the Request in the future – in this case, the Configuration Request Retry Status 100 (CRS) Completion Status is used. As per PCI spec, CRS Software Visibility only affects config read of the Vendor ID, for config write or any other config read the Root must automatically re-issue configuration request again as a new request. Iproc based PCIe RC (hw) does not retry request on its own. As a result of the fact, PCIe RC driver (sw) should take care of CRS. This patch fixes the problem, and attempts to read config space again in case of PCIe code forwarding the CRS back to CPU. It implements iproc_pcie_config_read which gets called for Stingray, Otherwise it falls back to PCI generic APIs. Signed-off-by: Oza Pawandeep Reviewed-by: Ray Jui Reviewed-by: Scott Branden diff --git a/drivers/pci/host/pcie-iproc.c b/drivers/pci/host/pcie-iproc.c index 0f39bd2..b0abcd7 100644 --- a/drivers/pci/host/pcie-iproc.c +++ b/drivers/pci/host/pcie-iproc.c @@ -68,6 +68,9 @@ #define APB_ERR_EN_SHIFT 0 #define APB_ERR_EN BIT(APB_ERR_EN_SHIFT) +#define CFG_RETRY_STATUS 0xffff0001 +#define CFG_RETRY_STATUS_TIMEOUT_US 500000 /* 500 milli-seconds. */ + /* derive the enum index of the outbound/inbound mapping registers */ #define MAP_REG(base_reg, index) ((base_reg) + (index) * 2) @@ -448,6 +451,55 @@ static inline void iproc_pcie_apb_err_disable(struct pci_bus *bus, } } +static int iproc_pcie_cfg_retry(void __iomem *cfg_data_p) +{ + int timeout = CFG_RETRY_STATUS_TIMEOUT_US; + unsigned int ret; + + /* + * As per PCI spec, CRS Software Visibility only + * affects config read of the Vendor ID. + * For config write or any other config read the Root must + * automatically re-issue configuration request again as a + * new request. Iproc based PCIe RC (hw) does not retry + * request on its own, so handle it here. + */ + do { + ret = readl(cfg_data_p); + if (ret == CFG_RETRY_STATUS) + udelay(1); + else + return PCIBIOS_SUCCESSFUL; + } while (timeout--); + + return PCIBIOS_DEVICE_NOT_FOUND; +} + +static void __iomem *iproc_pcie_map_ep_cfg_reg(struct iproc_pcie *pcie, + unsigned int busno, + unsigned int slot, + unsigned int fn, + int where) +{ + u16 offset; + u32 val; + + /* EP device access */ + val = (busno << CFG_ADDR_BUS_NUM_SHIFT) | + (slot << CFG_ADDR_DEV_NUM_SHIFT) | + (fn << CFG_ADDR_FUNC_NUM_SHIFT) | + (where & CFG_ADDR_REG_NUM_MASK) | + (1 & CFG_ADDR_CFG_TYPE_MASK); + + iproc_pcie_write_reg(pcie, IPROC_PCIE_CFG_ADDR, val); + offset = iproc_pcie_reg_offset(pcie, IPROC_PCIE_CFG_DATA); + + if (iproc_pcie_reg_is_invalid(offset)) + return NULL; + + return (pcie->base + offset); +} + /** * Note access to the configuration registers are protected at the higher layer * by 'pci_lock' in drivers/pci/access.c @@ -499,13 +551,48 @@ static void __iomem *iproc_pcie_map_cfg_bus(struct pci_bus *bus, return (pcie->base + offset); } +static int iproc_pcie_config_read(struct pci_bus *bus, unsigned int devfn, + int where, int size, u32 *val) +{ + struct iproc_pcie *pcie = iproc_data(bus); + unsigned int slot = PCI_SLOT(devfn); + unsigned int fn = PCI_FUNC(devfn); + unsigned int busno = bus->number; + void __iomem *cfg_data_p; + int ret; + + /* root complex access. */ + if (busno == 0) + return pci_generic_config_read32(bus, devfn, where, size, val); + + cfg_data_p = iproc_pcie_map_ep_cfg_reg(pcie, busno, slot, fn, where); + + if (!cfg_data_p) + return PCIBIOS_DEVICE_NOT_FOUND; + + ret = iproc_pcie_cfg_retry(cfg_data_p); + if (ret) + return ret; + + *val = readl(cfg_data_p); + + if (size <= 2) + *val = (*val >> (8 * (where & 3))) & ((1 << (size * 8)) - 1); + + return PCIBIOS_SUCCESSFUL; +} + static int iproc_pcie_config_read32(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *val) { int ret; + struct iproc_pcie *pcie = iproc_data(bus); iproc_pcie_apb_err_disable(bus, true); - ret = pci_generic_config_read32(bus, devfn, where, size, val); + if (pcie->type == IPROC_PCIE_PAXB_V2) + ret = iproc_pcie_config_read(bus, devfn, where, size, val); + else + ret = pci_generic_config_read32(bus, devfn, where, size, val); iproc_pcie_apb_err_disable(bus, false); return ret;