From patchwork Fri Sep 27 08:55:02 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Remi Pommarel X-Patchwork-Id: 11164079 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6550913B1 for ; Fri, 27 Sep 2019 08:46:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 42A60217D7 for ; Fri, 27 Sep 2019 08:46:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725992AbfI0Iqr (ORCPT ); Fri, 27 Sep 2019 04:46:47 -0400 Received: from relay5-d.mail.gandi.net ([217.70.183.197]:51479 "EHLO relay5-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725882AbfI0Iqr (ORCPT ); Fri, 27 Sep 2019 04:46:47 -0400 X-Originating-IP: 65.39.69.237 Received: from localhost (unknown [65.39.69.237]) (Authenticated sender: repk@triplefau.lt) by relay5-d.mail.gandi.net (Postfix) with ESMTPSA id 0C35C1C000B; Fri, 27 Sep 2019 08:46:44 +0000 (UTC) From: Remi Pommarel To: Thomas Petazzoni , Lorenzo Pieralisi , Bjorn Helgaas Cc: linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Remi Pommarel Subject: [PATCH v3] PCI: aardvark: Don't rely on jiffies while holding spinlock Date: Fri, 27 Sep 2019 10:55:02 +0200 Message-Id: <20190927085502.1758-1-repk@triplefau.lt> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org advk_pcie_wait_pio() can be called while holding a spinlock (from pci_bus_read_config_dword()), then depends on jiffies in order to timeout while polling on PIO state registers. In the case the PIO transaction failed, the timeout will never happen and will also cause the cpu to stall. This decrements a variable and wait instead of using jiffies. Signed-off-by: Remi Pommarel Acked-by: Thomas Petazzoni Reviewed-by: Andrew Murray --- Changes since v1: - Reduce polling delay - Change size_t into int for loop counter Changes since v2: - Keep timeout to 1ms by increasing retry counter --- drivers/pci/controller/pci-aardvark.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index fc0fe4d4de49..7b5c9d6c8706 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -175,7 +175,8 @@ (PCIE_CONF_BUS(bus) | PCIE_CONF_DEV(PCI_SLOT(devfn)) | \ PCIE_CONF_FUNC(PCI_FUNC(devfn)) | PCIE_CONF_REG(where)) -#define PIO_TIMEOUT_MS 1 +#define PIO_RETRY_CNT 500 +#define PIO_RETRY_DELAY 2 /* 2 us*/ #define LINK_WAIT_MAX_RETRIES 10 #define LINK_WAIT_USLEEP_MIN 90000 @@ -383,17 +384,16 @@ static void advk_pcie_check_pio_status(struct advk_pcie *pcie) static int advk_pcie_wait_pio(struct advk_pcie *pcie) { struct device *dev = &pcie->pdev->dev; - unsigned long timeout; + int i; - timeout = jiffies + msecs_to_jiffies(PIO_TIMEOUT_MS); - - while (time_before(jiffies, timeout)) { + for (i = 0; i < PIO_RETRY_CNT; i++) { u32 start, isr; start = advk_readl(pcie, PIO_START); isr = advk_readl(pcie, PIO_ISR); if (!start && isr) return 0; + udelay(PIO_RETRY_DELAY); } dev_err(dev, "config read/write timed out\n");