From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80378C43331 for ; Thu, 26 Mar 2020 17:02:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5728A20714 for ; Thu, 26 Mar 2020 17:02:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727655AbgCZRCn (ORCPT ); Thu, 26 Mar 2020 13:02:43 -0400 Received: from foss.arm.com ([217.140.110.172]:35044 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726496AbgCZRCn (ORCPT ); Thu, 26 Mar 2020 13:02:43 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6AA0D7FA; Thu, 26 Mar 2020 10:02:42 -0700 (PDT) Received: from e121166-lin.cambridge.arm.com (e121166-lin.cambridge.arm.com [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6A0DD3F71E; Thu, 26 Mar 2020 10:02:41 -0700 (PDT) Date: Thu, 26 Mar 2020 17:02:36 +0000 From: Lorenzo Pieralisi To: Vignesh Raghavendra Cc: Kishon Vijay Abraham I , Bjorn Helgaas , Andrew Murray , linux-omap@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] PCI: dwc: pci-dra7xx: Fix MSI IRQ handling Message-ID: <20200326170236.GA11968@e121166-lin.cambridge.arm.com> References: <20200326152826.31851-1-vigneshr@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200326152826.31851-1-vigneshr@ti.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org On Thu, Mar 26, 2020 at 08:58:26PM +0530, Vignesh Raghavendra wrote: > Due an issue with PCIe wrapper around DWC PCIe IP on dra7xx, driver > needs to ensure that there are no pending MSI IRQ vector set (i.e > PCIE_MSI_INTR0_STATUS reads 0 at least once) before exiting IRQ handler. > Else, the dra7xx PCIe wrapper will not register new MSI IRQs even though > PCIE_MSI_INTR0_STATUS shows IRQs are pending. > > Therefore its no longer possible to use default IRQ handler provided by > DWC library. So, add irqchip implementation inside pci-dra7xx.c and > install new MSI IRQ handler to handle above errata. > > This fixes a bug, where PCIe wifi cards with 4 DMA queues like Intel > 8260 used to throw following error and stall during ping/iperf3 tests. > > [ 97.776310] iwlwifi 0000:01:00.0: Queue 9 stuck for 2500 ms. > > Signed-off-by: Vignesh Raghavendra > Acked-by: Kishon Vijay Abraham I > Tested-by: Kishon Vijay Abraham I > --- > > v3: > Fix comments from Lorenzo: > - Move loop to service all MSI IRQs into dra7xx_pcie_handle_msi_irq() > - Add a warning msg when loop counter overflows > > > drivers/pci/controller/dwc/pci-dra7xx.c | 233 ++++++++++++++++++++---- > 1 file changed, 196 insertions(+), 37 deletions(-) > > diff --git a/drivers/pci/controller/dwc/pci-dra7xx.c b/drivers/pci/controller/dwc/pci-dra7xx.c > index 9bf7fa99b103..db33a3cb4348 100644 > --- a/drivers/pci/controller/dwc/pci-dra7xx.c > +++ b/drivers/pci/controller/dwc/pci-dra7xx.c > @@ -215,10 +215,6 @@ static int dra7xx_pcie_host_init(struct pcie_port *pp) > return 0; > } > > -static const struct dw_pcie_host_ops dra7xx_pcie_host_ops = { > - .host_init = dra7xx_pcie_host_init, > -}; > - > static int dra7xx_pcie_intx_map(struct irq_domain *domain, unsigned int irq, > irq_hw_number_t hwirq) > { > @@ -233,43 +229,77 @@ static const struct irq_domain_ops intx_domain_ops = { > .xlate = pci_irqd_intx_xlate, > }; > > -static int dra7xx_pcie_init_irq_domain(struct pcie_port *pp) > +static int dra7xx_pcie_handle_msi_irq_once(struct pcie_port *pp) > { > struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > - struct device *dev = pci->dev; > - struct dra7xx_pcie *dra7xx = to_dra7xx_pcie(pci); > - struct device_node *node = dev->of_node; > - struct device_node *pcie_intc_node = of_get_next_child(node, NULL); > - > - if (!pcie_intc_node) { > - dev_err(dev, "No PCIe Intc node found\n"); > - return -ENODEV; > + u32 status, num_ctrls; > + unsigned long val; > + int i, pos, irq; > + int ret = 0; > + > + num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL; > + > + for (i = 0; i < num_ctrls; i++) { Move this inner loop in a function: int dra7xx_handle_msi(int idx) {} and then ... do { ret = 0; for (i = 0; i < num_ctrls; i++) ret |= dra7xx_handle_msi(i); count++; } while (ret && count <= 1000); if (count > 1000) dev_warn_ratelimited(pci->dev, "Too many MSI IRQs to handle\n"); IMO It is more readable to have the whole handling logic in a single function - up to you. > + status = dw_pcie_readl_dbi(pci, PCIE_MSI_INTR0_STATUS + > + (i * MSI_REG_CTRL_BLOCK_SIZE)); > + if (!status) > + continue; > + > + ret = 1; > + val = status; > + pos = 0; > + while ((pos = find_next_bit(&val, MAX_MSI_IRQS_PER_CTRL, > + pos)) != MAX_MSI_IRQS_PER_CTRL) { I'd rather have the assignment in a separate line. Thanks, Lorenzo > + irq = irq_find_mapping(pp->irq_domain, > + (i * MAX_MSI_IRQS_PER_CTRL) + > + pos); > + generic_handle_irq(irq); > + pos++; > + } > } > > - dra7xx->irq_domain = irq_domain_add_linear(pcie_intc_node, PCI_NUM_INTX, > - &intx_domain_ops, pp); > - of_node_put(pcie_intc_node); > - if (!dra7xx->irq_domain) { > - dev_err(dev, "Failed to get a INTx IRQ domain\n"); > - return -ENODEV; > - } > + return ret; > +} > > - return 0; > +static void dra7xx_pcie_handle_msi_irq(struct pcie_port *pp) > +{ > + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > + int count = 0; > + > + /** > + * Need to make sure all MSI status bits read 0 before exiting. > + * Else, new MSI IRQs are not registered by the wrapper. Have an > + * upperbound for the loop and exit the IRQ in case of IRQ flood > + * to avoid locking up system in interrupt context. > + */ > + while (dra7xx_pcie_handle_msi_irq_once(pp) && count < 1000) > + count++; > + > + if (count == 1000) > + dev_warn(pci->dev, "Too many MSI IRQs to handle\n"); > } > > -static irqreturn_t dra7xx_pcie_msi_irq_handler(int irq, void *arg) > +static void dra7xx_pcie_msi_irq_handler(struct irq_desc *desc) > { > - struct dra7xx_pcie *dra7xx = arg; > - struct dw_pcie *pci = dra7xx->pci; > - struct pcie_port *pp = &pci->pp; > + struct irq_chip *chip = irq_desc_get_chip(desc); > + struct dra7xx_pcie *dra7xx; > + struct dw_pcie *pci; > + struct pcie_port *pp; > unsigned long reg; > u32 virq, bit; > > + chained_irq_enter(chip, desc); > + > + pp = irq_desc_get_handler_data(desc); > + pci = to_dw_pcie_from_pp(pp); > + dra7xx = to_dra7xx_pcie(pci); > + > reg = dra7xx_pcie_readl(dra7xx, PCIECTRL_DRA7XX_CONF_IRQSTATUS_MSI); > + dra7xx_pcie_writel(dra7xx, PCIECTRL_DRA7XX_CONF_IRQSTATUS_MSI, reg); > > switch (reg) { > case MSI: > - dw_handle_msi_irq(pp); > + dra7xx_pcie_handle_msi_irq(pp); > break; > case INTA: > case INTB: > @@ -283,9 +313,7 @@ static irqreturn_t dra7xx_pcie_msi_irq_handler(int irq, void *arg) > break; > } > > - dra7xx_pcie_writel(dra7xx, PCIECTRL_DRA7XX_CONF_IRQSTATUS_MSI, reg); > - > - return IRQ_HANDLED; > + chained_irq_exit(chip, desc); > } > > static irqreturn_t dra7xx_pcie_irq_handler(int irq, void *arg) > @@ -347,6 +375,145 @@ static irqreturn_t dra7xx_pcie_irq_handler(int irq, void *arg) > return IRQ_HANDLED; > } > > +static int dra7xx_pcie_init_irq_domain(struct pcie_port *pp) > +{ > + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > + struct device *dev = pci->dev; > + struct dra7xx_pcie *dra7xx = to_dra7xx_pcie(pci); > + struct device_node *node = dev->of_node; > + struct device_node *pcie_intc_node = of_get_next_child(node, NULL); > + > + if (!pcie_intc_node) { > + dev_err(dev, "No PCIe Intc node found\n"); > + return -ENODEV; > + } > + > + irq_set_chained_handler_and_data(pp->irq, dra7xx_pcie_msi_irq_handler, > + pp); > + dra7xx->irq_domain = irq_domain_add_linear(pcie_intc_node, PCI_NUM_INTX, > + &intx_domain_ops, pp); > + of_node_put(pcie_intc_node); > + if (!dra7xx->irq_domain) { > + dev_err(dev, "Failed to get a INTx IRQ domain\n"); > + return -ENODEV; > + } > + > + return 0; > +} > + > +static void dra7xx_pcie_setup_msi_msg(struct irq_data *d, struct msi_msg *msg) > +{ > + struct pcie_port *pp = irq_data_get_irq_chip_data(d); > + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > + u64 msi_target; > + > + msi_target = (u64)pp->msi_data; > + > + msg->address_lo = lower_32_bits(msi_target); > + msg->address_hi = upper_32_bits(msi_target); > + > + msg->data = d->hwirq; > + > + dev_dbg(pci->dev, "msi#%d address_hi %#x address_lo %#x\n", > + (int)d->hwirq, msg->address_hi, msg->address_lo); > +} > + > +static int dra7xx_pcie_msi_set_affinity(struct irq_data *d, > + const struct cpumask *mask, > + bool force) > +{ > + return -EINVAL; > +} > + > +static void dra7xx_pcie_bottom_mask(struct irq_data *d) > +{ > + struct pcie_port *pp = irq_data_get_irq_chip_data(d); > + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > + unsigned int res, bit, ctrl; > + unsigned long flags; > + > + raw_spin_lock_irqsave(&pp->lock, flags); > + > + ctrl = d->hwirq / MAX_MSI_IRQS_PER_CTRL; > + res = ctrl * MSI_REG_CTRL_BLOCK_SIZE; > + bit = d->hwirq % MAX_MSI_IRQS_PER_CTRL; > + > + pp->irq_mask[ctrl] |= BIT(bit); > + dw_pcie_writel_dbi(pci, PCIE_MSI_INTR0_MASK + res, > + pp->irq_mask[ctrl]); > + > + raw_spin_unlock_irqrestore(&pp->lock, flags); > +} > + > +static void dra7xx_pcie_bottom_unmask(struct irq_data *d) > +{ > + struct pcie_port *pp = irq_data_get_irq_chip_data(d); > + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > + unsigned int res, bit, ctrl; > + unsigned long flags; > + > + raw_spin_lock_irqsave(&pp->lock, flags); > + > + ctrl = d->hwirq / MAX_MSI_IRQS_PER_CTRL; > + res = ctrl * MSI_REG_CTRL_BLOCK_SIZE; > + bit = d->hwirq % MAX_MSI_IRQS_PER_CTRL; > + > + pp->irq_mask[ctrl] &= ~BIT(bit); > + dw_pcie_writel_dbi(pci, PCIE_MSI_INTR0_MASK + res, > + pp->irq_mask[ctrl]); > + > + raw_spin_unlock_irqrestore(&pp->lock, flags); > +} > + > +static void dra7xx_pcie_bottom_ack(struct irq_data *d) > +{ > + struct pcie_port *pp = irq_data_get_irq_chip_data(d); > + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > + unsigned int res, bit, ctrl; > + > + ctrl = d->hwirq / MAX_MSI_IRQS_PER_CTRL; > + res = ctrl * MSI_REG_CTRL_BLOCK_SIZE; > + bit = d->hwirq % MAX_MSI_IRQS_PER_CTRL; > + > + dw_pcie_writel_dbi(pci, PCIE_MSI_INTR0_STATUS + res, BIT(bit)); > +} > + > +static struct irq_chip dra7xx_pci_msi_bottom_irq_chip = { > + .name = "DRA7XX-PCI-MSI", > + .irq_ack = dra7xx_pcie_bottom_ack, > + .irq_compose_msi_msg = dra7xx_pcie_setup_msi_msg, > + .irq_set_affinity = dra7xx_pcie_msi_set_affinity, > + .irq_mask = dra7xx_pcie_bottom_mask, > + .irq_unmask = dra7xx_pcie_bottom_unmask, > +}; > + > +static int dra7xx_pcie_msi_host_init(struct pcie_port *pp) > +{ > + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > + u32 ctrl, num_ctrls; > + > + pp->msi_irq_chip = &dra7xx_pci_msi_bottom_irq_chip; > + > + num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL; > + /* Initialize IRQ Status array */ > + for (ctrl = 0; ctrl < num_ctrls; ctrl++) { > + pp->irq_mask[ctrl] = ~0; > + dw_pcie_writel_dbi(pci, PCIE_MSI_INTR0_MASK + > + (ctrl * MSI_REG_CTRL_BLOCK_SIZE), > + pp->irq_mask[ctrl]); > + dw_pcie_writel_dbi(pci, PCIE_MSI_INTR0_ENABLE + > + (ctrl * MSI_REG_CTRL_BLOCK_SIZE), > + ~0); > + } > + > + return dw_pcie_allocate_domains(pp); > +} > + > +static const struct dw_pcie_host_ops dra7xx_pcie_host_ops = { > + .host_init = dra7xx_pcie_host_init, > + .msi_host_init = dra7xx_pcie_msi_host_init, > +}; > + > static void dra7xx_pcie_ep_init(struct dw_pcie_ep *ep) > { > struct dw_pcie *pci = to_dw_pcie_from_ep(ep); > @@ -467,14 +634,6 @@ static int __init dra7xx_add_pcie_port(struct dra7xx_pcie *dra7xx, > return pp->irq; > } > > - ret = devm_request_irq(dev, pp->irq, dra7xx_pcie_msi_irq_handler, > - IRQF_SHARED | IRQF_NO_THREAD, > - "dra7-pcie-msi", dra7xx); > - if (ret) { > - dev_err(dev, "failed to request irq\n"); > - return ret; > - } > - > ret = dra7xx_pcie_init_irq_domain(pp); > if (ret < 0) > return ret; > -- > 2.26.0 >