From patchwork Mon Jan 17 22:03:54 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 12715695 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E0BAC4332F for ; Mon, 17 Jan 2022 22:04:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237607AbiAQWES (ORCPT ); Mon, 17 Jan 2022 17:04:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56914 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233580AbiAQWES (ORCPT ); Mon, 17 Jan 2022 17:04:18 -0500 Received: from phobos.denx.de (phobos.denx.de [IPv6:2a01:238:438b:c500:173d:9f52:ddab:ee01]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA5C9C061574; Mon, 17 Jan 2022 14:04:17 -0800 (PST) Received: from tr.lan (ip-89-176-112-137.net.upcbroadband.cz [89.176.112.137]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: marex@denx.de) by phobos.denx.de (Postfix) with ESMTPSA id 4982D830C0; Mon, 17 Jan 2022 23:04:14 +0100 (CET) From: marek.vasut@gmail.com To: linux-pci@vger.kernel.org Cc: Marek Vasut , Arnd Bergmann , Bjorn Helgaas , Geert Uytterhoeven , =?utf-8?q?Krzysztof_Wilczy?= =?utf-8?q?=C5=84ski?= , Lorenzo Pieralisi , Wolfram Sang , Yoshihiro Shimoda , linux-renesas-soc@vger.kernel.org Subject: [PATCH v2 1/2] PCI: rcar: Finish transition to L1 state in rcar_pcie_config_access() Date: Mon, 17 Jan 2022 23:03:54 +0100 Message-Id: <20220117220355.92575-1-marek.vasut@gmail.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Virus-Scanned: clamav-milter 0.103.2 at phobos.denx.de X-Virus-Status: Clean Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Marek Vasut In case the controller is transitioning to L1 in rcar_pcie_config_access(), any read/write access to PCIECDR triggers asynchronous external abort. This is because the transition to L1 link state must be manually finished by the driver. The PCIe IP can transition back from L1 state to L0 on its own. Avoid triggering the abort in rcar_pcie_config_access() by checking whether the controller is in the transition state, and if so, finish the transition right away. This prevents a lot of unnecessary exceptions, although not all of them. Signed-off-by: Marek Vasut Cc: Arnd Bergmann Cc: Bjorn Helgaas Cc: Geert Uytterhoeven Cc: Krzysztof Wilczyński Cc: Lorenzo Pieralisi Cc: Wolfram Sang Cc: Yoshihiro Shimoda Cc: linux-renesas-soc@vger.kernel.org --- V2: Pull DEFINE_SPINLOCK(pmsr_lock) and rcar_pcie_wakeup() out of ifdef(CONFIG_ARM), since this change is applicable even on arm64 --- drivers/pci/controller/pcie-rcar-host.c | 78 ++++++++++++++++--------- 1 file changed, 49 insertions(+), 29 deletions(-) diff --git a/drivers/pci/controller/pcie-rcar-host.c b/drivers/pci/controller/pcie-rcar-host.c index 38b6e02edfa9..f0a0d560fefc 100644 --- a/drivers/pci/controller/pcie-rcar-host.c +++ b/drivers/pci/controller/pcie-rcar-host.c @@ -41,6 +41,15 @@ struct rcar_msi { int irq2; }; +/* Structure representing the PCIe interface */ +struct rcar_pcie_host { + struct rcar_pcie pcie; + struct phy *phy; + struct clk *bus_clk; + struct rcar_msi msi; + int (*phy_init_fn)(struct rcar_pcie_host *host); +}; + #ifdef CONFIG_ARM /* * Here we keep a static copy of the remapped PCIe controller address. @@ -56,14 +65,34 @@ static void __iomem *pcie_base; static struct device *pcie_dev; #endif -/* Structure representing the PCIe interface */ -struct rcar_pcie_host { - struct rcar_pcie pcie; - struct phy *phy; - struct clk *bus_clk; - struct rcar_msi msi; - int (*phy_init_fn)(struct rcar_pcie_host *host); -}; +static DEFINE_SPINLOCK(pmsr_lock); + +static int rcar_pcie_wakeup(struct device *pcie_dev, void __iomem *pcie_base) +{ + u32 pmsr, val; + int ret = 0; + + if (!pcie_base || pm_runtime_suspended(pcie_dev)) + return 1; + + pmsr = readl(pcie_base + PMSR); + + /* + * Test if the PCIe controller received PM_ENTER_L1 DLLP and + * the PCIe controller is not in L1 link state. If true, apply + * fix, which will put the controller into L1 link state, from + * which it can return to L0s/L0 on its own. + */ + if ((pmsr & PMEL1RX) && ((pmsr & PMSTATE) != PMSTATE_L1)) { + writel(L1IATN, pcie_base + PMCTLR); + ret = readl_poll_timeout_atomic(pcie_base + PMSR, val, + val & L1FAEG, 10, 1000); + WARN(ret, "Timeout waiting for L1 link state, ret=%d\n", ret); + writel(L1FAEG | PMEL1RX, pcie_base + PMSR); + } + + return ret; +} static struct rcar_pcie_host *msi_to_host(struct rcar_msi *msi) { @@ -85,6 +114,15 @@ static int rcar_pcie_config_access(struct rcar_pcie_host *host, { struct rcar_pcie *pcie = &host->pcie; unsigned int dev, func, reg, index; + unsigned long flags; + int ret; + + /* Wake the bus up in case it is in L1 state. */ + spin_lock_irqsave(&pmsr_lock, flags); + ret = rcar_pcie_wakeup(pcie->dev, pcie->base); + spin_unlock_irqrestore(&pmsr_lock, flags); + if (ret) + return ret; dev = PCI_SLOT(devfn); func = PCI_FUNC(devfn); @@ -1050,36 +1088,18 @@ static struct platform_driver rcar_pcie_driver = { }; #ifdef CONFIG_ARM -static DEFINE_SPINLOCK(pmsr_lock); static int rcar_pcie_aarch32_abort_handler(unsigned long addr, unsigned int fsr, struct pt_regs *regs) { unsigned long flags; - u32 pmsr, val; int ret = 0; spin_lock_irqsave(&pmsr_lock, flags); - if (!pcie_base || pm_runtime_suspended(pcie_dev)) { - ret = 1; + ret = rcar_pcie_wakeup(pcie_dev, pcie_base); + spin_unlock_irqrestore(&pmsr_lock, flags); + if (ret) goto unlock_exit; - } - - pmsr = readl(pcie_base + PMSR); - - /* - * Test if the PCIe controller received PM_ENTER_L1 DLLP and - * the PCIe controller is not in L1 link state. If true, apply - * fix, which will put the controller into L1 link state, from - * which it can return to L0s/L0 on its own. - */ - if ((pmsr & PMEL1RX) && ((pmsr & PMSTATE) != PMSTATE_L1)) { - writel(L1IATN, pcie_base + PMCTLR); - ret = readl_poll_timeout_atomic(pcie_base + PMSR, val, - val & L1FAEG, 10, 1000); - WARN(ret, "Timeout waiting for L1 link state, ret=%d\n", ret); - writel(L1FAEG | PMEL1RX, pcie_base + PMSR); - } unlock_exit: spin_unlock_irqrestore(&pmsr_lock, flags);