From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6AD0C1170D for ; Mon, 11 Sep 2023 14:11:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DEAF5C433C8; Mon, 11 Sep 2023 14:11:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1694441496; bh=Nji1C/hhKWRs9P1TLr8QVGaZS/We7XM5weKvAhCLqGc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=v56uM4EUaCtRCeFcj6hFFYFj1d8J7Izo0lL8uZyYoGJRUR7uZWQyYeJHjTYB9BiF7 oJMAo29o7YkzFoM9m3k9t/XjqS/3KFzzChwDFzVlpH37LsOSvzYfFrnpuvL0zCkLUO AGKMKMvD3AH4H9XsaBhHRKSKGdACBQq9t6Y5fPew= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Lukas Wunner , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Bjorn Helgaas , "Rafael J. Wysocki" , Sasha Levin Subject: [PATCH 6.5 406/739] PCI: Make link retraining use RMW accessors for changing LNKCTL Date: Mon, 11 Sep 2023 15:43:25 +0200 Message-ID: <20230911134702.517493323@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230911134650.921299741@linuxfoundation.org> References: <20230911134650.921299741@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ilpo Järvinen [ Upstream commit fb0171a4c01b4825e36a5584eaa84291179c64ce ] Don't assume that the device is fully under the control of PCI core. Use RMW capability accessors in link retraining which do proper locking to avoid losing concurrent updates to the register values. Suggested-by: Lukas Wunner Fixes: 4ec73791a64b ("PCI: Work around Pericom PCIe-to-PCI bridge Retrain Link erratum") Fixes: 7d715a6c1ae5 ("PCI: add PCI Express ASPM support") Link: https://lore.kernel.org/r/20230717120503.15276-3-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Acked-by: "Rafael J. Wysocki" Signed-off-by: Sasha Levin --- drivers/pci/pci.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 60230da957e0c..f7315b13bb826 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4927,7 +4927,6 @@ static int pcie_wait_for_link_status(struct pci_dev *pdev, int pcie_retrain_link(struct pci_dev *pdev, bool use_lt) { int rc; - u16 lnkctl; /* * Ensure the updated LNKCTL parameters are used during link @@ -4939,17 +4938,14 @@ int pcie_retrain_link(struct pci_dev *pdev, bool use_lt) if (rc) return rc; - pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &lnkctl); - lnkctl |= PCI_EXP_LNKCTL_RL; - pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnkctl); + pcie_capability_set_word(pdev, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_RL); if (pdev->clear_retrain_link) { /* * Due to an erratum in some devices the Retrain Link bit * needs to be cleared again manually to allow the link * training to succeed. */ - lnkctl &= ~PCI_EXP_LNKCTL_RL; - pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnkctl); + pcie_capability_clear_word(pdev, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_RL); } return pcie_wait_for_link_status(pdev, use_lt, !use_lt); -- 2.40.1