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From:   =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
To:     linux-pci@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Rob Herring <robh@kernel.org>,
        =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= <kw@linux.com>,
        Emmanuel Grumbach <emmanuel.grumbach@intel.com>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Lukas Wunner <lukas@wunner.de>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Jesse Barnes <jbarnes@virtuousgeek.org>,
        Yinghai Lu <yinghai@kernel.org>, linux-kernel@vger.kernel.org
Cc:     Dean Luick <dean.luick@cornelisnetworks.com>,
        =?UTF-8?q?Jonas=20Dre=C3=9Fler?= <verdre@v0yd.nl>,
        =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>,
        stable@vger.kernel.org
Subject: [PATCH v5 03/11] PCI: pciehp: Use RMW accessors for changing LNKCTL
Date:   Mon, 17 Jul 2023 15:04:55 +0300
Message-Id: <20230717120503.15276-4-ilpo.jarvinen@linux.intel.com>
In-Reply-To: <20230717120503.15276-1-ilpo.jarvinen@linux.intel.com>
References: <20230717120503.15276-1-ilpo.jarvinen@linux.intel.com>
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As hotplug is not the only driver touching LNKCTL, use the RMW
capability accessor which handles concurrent changes correctly.

Fixes: 7f822999e12a ("PCI: pciehp: Add Disable/enable link functions")
Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Cc: stable@vger.kernel.org
---
 drivers/pci/hotplug/pciehp_hpc.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 8711325605f0..fd713abdfb9f 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -332,17 +332,11 @@ int pciehp_check_link_status(struct controller *ctrl)
 static int __pciehp_link_set(struct controller *ctrl, bool enable)
 {
 	struct pci_dev *pdev = ctrl_dev(ctrl);
-	u16 lnk_ctrl;
 
-	pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &lnk_ctrl);
+	pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL,
+					   PCI_EXP_LNKCTL_LD,
+					   enable ? 0 : PCI_EXP_LNKCTL_LD);
 
-	if (enable)
-		lnk_ctrl &= ~PCI_EXP_LNKCTL_LD;
-	else
-		lnk_ctrl |= PCI_EXP_LNKCTL_LD;
-
-	pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnk_ctrl);
-	ctrl_dbg(ctrl, "%s: lnk_ctrl = %x\n", __func__, lnk_ctrl);
 	return 0;
 }
 
-- 
2.30.2