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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 <helgaas@kernel.org>,
        Rob Herring <robh@kernel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= <kw@linux.com>,
        Lukas Wunner <lukas@wunner.de>,
        Siva Reddy Kallam <siva.kallam@broadcom.com>,
        Prashant Sreedharan <prashant@broadcom.com>,
        Michael Chan <mchan@broadcom.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
Subject: [PATCH 13/17] net/tg3: Use pcie_lnkctl_clear_and_set() for changing LNKCTL
Date:   Thu, 11 May 2023 16:14:37 +0300
Message-Id: <20230511131441.45704-14-ilpo.jarvinen@linux.intel.com>
In-Reply-To: <20230511131441.45704-1-ilpo.jarvinen@linux.intel.com>
References: <20230511131441.45704-1-ilpo.jarvinen@linux.intel.com>
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Don't assume that only the driver would be accessing LNKCTL. ASPM
policy changes can trigger write to LNKCTL outside of driver's control.

Use pcie_lnkctl_clear_and_set() which does proper locking to avoid
losing concurrent updates to the register value.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 drivers/net/ethernet/broadcom/tg3.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index 58747292521d..f3b30e7af25d 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -4027,8 +4027,7 @@ static int tg3_power_down_prepare(struct tg3 *tp)
 
 	/* Restore the CLKREQ setting. */
 	if (tg3_flag(tp, CLKREQ_BUG))
-		pcie_capability_set_word(tp->pdev, PCI_EXP_LNKCTL,
-					 PCI_EXP_LNKCTL_CLKREQ_EN);
+		pcie_lnkctl_clear_and_set(tp->pdev, 0, PCI_EXP_LNKCTL_CLKREQ_EN);
 
 	misc_host_ctrl = tr32(TG3PCI_MISC_HOST_CTRL);
 	tw32(TG3PCI_MISC_HOST_CTRL,
@@ -5069,13 +5068,14 @@ static int tg3_setup_copper_phy(struct tg3 *tp, bool force_reset)
 
 	/* Prevent send BD corruption. */
 	if (tg3_flag(tp, CLKREQ_BUG)) {
+		u16 clkreq = 0;
+
 		if (tp->link_config.active_speed == SPEED_100 ||
 		    tp->link_config.active_speed == SPEED_10)
-			pcie_capability_clear_word(tp->pdev, PCI_EXP_LNKCTL,
-						   PCI_EXP_LNKCTL_CLKREQ_EN);
-		else
-			pcie_capability_set_word(tp->pdev, PCI_EXP_LNKCTL,
-						 PCI_EXP_LNKCTL_CLKREQ_EN);
+			clkreq = PCI_EXP_LNKCTL_CLKREQ_EN;
+
+		pcie_lnkctl_clear_and_set(tp->pdev, PCI_EXP_LNKCTL_CLKREQ_EN,
+					  clkreq);
 	}
 
 	tg3_test_and_report_link_chg(tp, current_link_up);
-- 
2.30.2