From patchwork Sat Mar 12 21:23:48 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 12778940 X-Patchwork-Delegate: geert@linux-m68k.org 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 AB2AAC433F5 for ; Sat, 12 Mar 2022 21:24:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232727AbiCLVZa (ORCPT ); Sat, 12 Mar 2022 16:25:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54518 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229803AbiCLVZ3 (ORCPT ); Sat, 12 Mar 2022 16:25:29 -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 E37CF2B278; Sat, 12 Mar 2022 13:24:22 -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 8AFDE81F9A; Sat, 12 Mar 2022 22:24:19 +0100 (CET) From: marek.vasut@gmail.com To: linux-pci@vger.kernel.org Cc: Marek Vasut , Geert Uytterhoeven , Arnd Bergmann , Bjorn Helgaas , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , Lorenzo Pieralisi , Wolfram Sang , Yoshihiro Shimoda , linux-renesas-soc@vger.kernel.org Subject: [PATCH v6 1/2] PCI: rcar: Finish transition to L1 state in rcar_pcie_config_access() Date: Sat, 12 Mar 2022 22:23:48 +0100 Message-Id: <20220312212349.781799-1-marek.vasut@gmail.com> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 X-Virus-Scanned: clamav-milter 0.103.5 at phobos.denx.de X-Virus-Status: Clean Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@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. Reviewed-by: Geert Uytterhoeven Tested-by: Geert Uytterhoeven 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 V3: - Convert non-zero return value from rcar_pcie_wakeup() in either PCIBIOS_SET_FAILED in rcar_pcie_config_access(), or, 1 in rcar_pcie_aarch32_abort_handler(). - Set error response using PCI_SET_ERROR_RESPONSE() in rcar_pcie_config_access() - Fix double spinlock unlock in rcar_pcie_aarch32_abort_handler(). V4: No change V5: No change V6: Add RB/TB from Geert --- drivers/pci/controller/pcie-rcar-host.c | 76 +++++++++++++++---------- 1 file changed, 45 insertions(+), 31 deletions(-) diff --git a/drivers/pci/controller/pcie-rcar-host.c b/drivers/pci/controller/pcie-rcar-host.c index dfca59c4ae34..0966cf63d9b3 100644 --- a/drivers/pci/controller/pcie-rcar-host.c +++ b/drivers/pci/controller/pcie-rcar-host.c @@ -65,6 +65,42 @@ struct rcar_pcie_host { 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) +{ + unsigned long flags; + u32 pmsr, val; + int ret = 0; + + spin_lock_irqsave(&pmsr_lock, flags); + + if (!pcie_base || pm_runtime_suspended(pcie_dev)) { + ret = -EINVAL; + 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); + return ret; +} + static struct rcar_pcie_host *msi_to_host(struct rcar_msi *msi) { return container_of(msi, struct rcar_pcie_host, msi); @@ -85,6 +121,14 @@ static int rcar_pcie_config_access(struct rcar_pcie_host *host, { struct rcar_pcie *pcie = &host->pcie; unsigned int dev, func, reg, index; + int ret; + + /* Wake the bus up in case it is in L1 state. */ + ret = rcar_pcie_wakeup(pcie->dev, pcie->base); + if (ret) { + PCI_SET_ERROR_RESPONSE(data); + return PCIBIOS_SET_FAILED; + } dev = PCI_SLOT(devfn); func = PCI_FUNC(devfn); @@ -1050,40 +1094,10 @@ 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; - 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); - return ret; + return !!rcar_pcie_wakeup(pcie_dev, pcie_base); } static const struct of_device_id rcar_pcie_abort_handler_of_match[] __initconst = {