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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>,
        Kalle Valo <kvalo@kernel.org>,
        Michal Kazior <michal.kazior@tieto.com>,
        Janusz Dziedzic <janusz.dziedzic@tieto.com>,
        ath10k@lists.infradead.org, linux-wireless@vger.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>,
        Simon Horman <simon.horman@corigine.com>,
        stable@vger.kernel.org
Subject: [PATCH v5 10/11] wifi: ath10k: Use RMW accessors for changing LNKCTL
Date:   Mon, 17 Jul 2023 15:05:02 +0300
Message-Id: <20230717120503.15276-11-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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Precedence: bulk

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 RMW capability accessors which does proper locking to avoid losing
concurrent updates to the register value. On restore, clear the ASPMC
field properly.

Fixes: 76d870ed09ab ("ath10k: enable ASPM")
Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Kalle Valo <kvalo@kernel.org>
Cc: stable@vger.kernel.org
---
 drivers/net/wireless/ath/ath10k/pci.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
index a7f44f6335fb..9275a672f90c 100644
--- a/drivers/net/wireless/ath/ath10k/pci.c
+++ b/drivers/net/wireless/ath/ath10k/pci.c
@@ -1963,8 +1963,9 @@ static int ath10k_pci_hif_start(struct ath10k *ar)
 	ath10k_pci_irq_enable(ar);
 	ath10k_pci_rx_post(ar);
 
-	pcie_capability_write_word(ar_pci->pdev, PCI_EXP_LNKCTL,
-				   ar_pci->link_ctl);
+	pcie_capability_clear_and_set_word(ar_pci->pdev, PCI_EXP_LNKCTL,
+					   PCI_EXP_LNKCTL_ASPMC,
+					   ar_pci->link_ctl & PCI_EXP_LNKCTL_ASPMC);
 
 	return 0;
 }
@@ -2821,8 +2822,8 @@ static int ath10k_pci_hif_power_up(struct ath10k *ar,
 
 	pcie_capability_read_word(ar_pci->pdev, PCI_EXP_LNKCTL,
 				  &ar_pci->link_ctl);
-	pcie_capability_write_word(ar_pci->pdev, PCI_EXP_LNKCTL,
-				   ar_pci->link_ctl & ~PCI_EXP_LNKCTL_ASPMC);
+	pcie_capability_clear_word(ar_pci->pdev, PCI_EXP_LNKCTL,
+				   PCI_EXP_LNKCTL_ASPMC);
 
 	/*
 	 * Bring the target up cleanly.
-- 
2.30.2