netdev - [PATCH 09/17] wifi: ath9k: Use pcie_lnkctl_clear_and

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Date: Thu, 11 May 2023 16:14:33 +0300
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: linux-pci@...r.kernel.org,
	Bjorn Helgaas <helgaas@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
	Krzysztof Wilczyński <kw@...ux.com>,
	Lukas Wunner <lukas@...ner.de>,
	Toke Høiland-Jørgensen <toke@...e.dk>,
	Kalle Valo <kvalo@...nel.org>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	linux-wireless@...r.kernel.org,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Subject: [PATCH 09/17] wifi: ath9k: Use pcie_lnkctl_clear_and_set() for changing LNKCTL

Don't assume that only the driver would be accessing LNKCTL. ASPM
policy changes can trigger write to LNKCTL outside of driver's control.
And in the case of upstream (parent), the driver does not even own the
device it's changing LNKCTL for.

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

Suggested-by: Lukas Wunner <lukas@...ner.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
---
 drivers/net/wireless/ath/ath9k/pci.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/pci.c b/drivers/net/wireless/ath/ath9k/pci.c
index a09f9d223f3d..c2130fe6c9e6 100644
--- a/drivers/net/wireless/ath/ath9k/pci.c
+++ b/drivers/net/wireless/ath/ath9k/pci.c
@@ -837,15 +837,16 @@ static void ath_pci_aspm_init(struct ath_common *common)
 	if ((ath9k_hw_get_btcoex_scheme(ah) != ATH_BTCOEX_CFG_NONE) &&
 	    (AR_SREV_9285(ah))) {
 		/* Bluetooth coexistence requires disabling ASPM. */
-		pcie_capability_clear_word(pdev, PCI_EXP_LNKCTL,
-			PCI_EXP_LNKCTL_ASPM_L0S | PCI_EXP_LNKCTL_ASPM_L1);
+		pcie_lnkctl_clear_and_set(pdev, PCI_EXP_LNKCTL_ASPM_L0S |
+						PCI_EXP_LNKCTL_ASPM_L1, 0);
 
 		/*
 		 * Both upstream and downstream PCIe components should
 		 * have the same ASPM settings.
 		 */
-		pcie_capability_clear_word(parent, PCI_EXP_LNKCTL,
-			PCI_EXP_LNKCTL_ASPM_L0S | PCI_EXP_LNKCTL_ASPM_L1);
+		pcie_lnkctl_clear_and_set(parent,
+					  PCI_EXP_LNKCTL_ASPM_L0S |
+					  PCI_EXP_LNKCTL_ASPM_L1, 0);
 
 		ath_info(common, "Disabling ASPM since BTCOEX is enabled\n");
 		return;
-- 
2.30.2