From patchwork Tue May 23 21:23:32 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 766231 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 3wXT6Q3bPlz9sNY for ; Wed, 24 May 2017 07:23:42 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1033893AbdEWVXj (ORCPT ); Tue, 23 May 2017 17:23:39 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:56235 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1032980AbdEWVXg (ORCPT ); Tue, 23 May 2017 17:23:36 -0400 Received: from localhost ([127.0.0.1]) by Galois.linutronix.de with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1dDHH6-0001jE-Kr; Tue, 23 May 2017 23:23:28 +0200 Date: Tue, 23 May 2017 23:23:32 +0200 (CEST) From: Thomas Gleixner To: LKML cc: Linus Walleij , linux-gpio@vger.kernel.org, Borislav Petkov , Ken Xue Subject: [PATCH] pinctrl/amd: Use regular interrupt instead of chained Message-ID: User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org The AMD pinctrl driver uses a chained interrupt to demultiplex the GPIO interrupts. Kevin Vandeventer reported, that his new AMD Ryzen locks up hard on boot when the AMD pinctrl driver is initialized. The reason is an interrupt storm. It's not clear whether that's caused by hardware or firmware or both. Using chained interrupts on X86 is a dangerous endavour. If a system is misconfigured or the hardware buggy there is no safety net to catch an interrupt storm. Convert the driver to use a regular interrupt for the demultiplex handler. This allows the interrupt storm detector to catch the malfunction and lets the system boot up. This should be backported to stable because it's likely that more users run into this problem as the AMD Ryzen machines are spreading. Reported-by: Kevin Vandeventer Link: https://bugzilla.suse.com/show_bug.cgi?id=1034261 Signed-off-by: Thomas Gleixner --- drivers/pinctrl/pinctrl-amd.c | 91 ++++++++++++++++++------------------------ 1 file changed, 41 insertions(+), 50 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- a/drivers/pinctrl/pinctrl-amd.c +++ b/drivers/pinctrl/pinctrl-amd.c @@ -495,64 +495,54 @@ static struct irq_chip amd_gpio_irqchip .flags = IRQCHIP_SKIP_SET_WAKE, }; -static void amd_gpio_irq_handler(struct irq_desc *desc) +#define PIN_IRQ_PENDING (BIT(INTERRUPT_STS_OFF) | BIT(WAKE_STS_OFF)) + +static irqreturn_t amd_gpio_irq_handler(int irq, void *dev_id) { - u32 i; - u32 off; - u32 reg; - u32 pin_reg; - u64 reg64; - int handled = 0; - unsigned int irq; + struct amd_gpio *gpio_dev = dev_id; + struct gpio_chip *gc = &gpio_dev->gc; + irqreturn_t ret = IRQ_NONE; + unsigned int i, irqnr; unsigned long flags; - struct irq_chip *chip = irq_desc_get_chip(desc); - struct gpio_chip *gc = irq_desc_get_handler_data(desc); - struct amd_gpio *gpio_dev = gpiochip_get_data(gc); + u32 *regs, regval; + u64 status, mask; - chained_irq_enter(chip, desc); - /*enable GPIO interrupt again*/ + /* Read the wake status */ raw_spin_lock_irqsave(&gpio_dev->lock, flags); - reg = readl(gpio_dev->base + WAKE_INT_STATUS_REG1); - reg64 = reg; - reg64 = reg64 << 32; - - reg = readl(gpio_dev->base + WAKE_INT_STATUS_REG0); - reg64 |= reg; + status = readl(gpio_dev->base + WAKE_INT_STATUS_REG1); + status <<= 32; + status |= readl(gpio_dev->base + WAKE_INT_STATUS_REG0); raw_spin_unlock_irqrestore(&gpio_dev->lock, flags); - /* - * first 46 bits indicates interrupt status. - * one bit represents four interrupt sources. - */ - for (off = 0; off < 46 ; off++) { - if (reg64 & BIT(off)) { - for (i = 0; i < 4; i++) { - pin_reg = readl(gpio_dev->base + - (off * 4 + i) * 4); - if ((pin_reg & BIT(INTERRUPT_STS_OFF)) || - (pin_reg & BIT(WAKE_STS_OFF))) { - irq = irq_find_mapping(gc->irqdomain, - off * 4 + i); - generic_handle_irq(irq); - writel(pin_reg, - gpio_dev->base - + (off * 4 + i) * 4); - handled++; - } - } + /* Bit 0-45 contain the relevant status bits */ + status &= (1ULL << 46) - 1; + regs = gpio_dev->base; + for (mask = 1, irqnr = 0; status; mask <<= 1, regs += 4, irqnr += 4) { + if (!(status & mask)) + continue; + status &= ~mask; + + /* Each status bit covers four pins */ + for (i = 0; i < 4; i++) { + regval = readl(regs + i); + if (!(regval & PIN_IRQ_PENDING)) + continue; + irq = irq_find_mapping(gc->irqdomain, irqnr + i); + generic_handle_irq(irq); + /* Clear interrupt */ + writel(regval, regs + i); + ret = IRQ_HANDLED; } } - if (handled == 0) - handle_bad_irq(desc); - + /* Signal EOI to the GPIO unit */ raw_spin_lock_irqsave(&gpio_dev->lock, flags); - reg = readl(gpio_dev->base + WAKE_INT_MASTER_REG); - reg |= EOI_MASK; - writel(reg, gpio_dev->base + WAKE_INT_MASTER_REG); + regval = readl(gpio_dev->base + WAKE_INT_MASTER_REG); + regval |= EOI_MASK; + writel(regval, gpio_dev->base + WAKE_INT_MASTER_REG); raw_spin_unlock_irqrestore(&gpio_dev->lock, flags); - chained_irq_exit(chip, desc); + return ret; } static int amd_get_groups_count(struct pinctrl_dev *pctldev) @@ -821,10 +811,11 @@ static int amd_gpio_probe(struct platfor goto out2; } - gpiochip_set_chained_irqchip(&gpio_dev->gc, - &amd_gpio_irqchip, - irq_base, - amd_gpio_irq_handler); + ret = devm_request_irq(&pdev->dev, irq_base, amd_gpio_irq_handler, 0, + KBUILD_MODNAME, gpio_dev); + if (ret) + goto out2; + platform_set_drvdata(pdev, gpio_dev); dev_dbg(&pdev->dev, "amd gpio driver loaded\n");