netdev - [PATCH 17/17] wifi: ath10k: Use pcie_lnkctl_clear_and

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Date: Thu, 11 May 2023 16:14:41 +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>,
	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>,
	ath10k@...ts.infradead.org,
	linux-wireless@...r.kernel.org,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Subject: [PATCH 17/17] wifi: ath10k: 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.

Use pcie_lnkctl_clear_and_set() which does proper locking to avoid
losing concurrent updates to the register value. Convert one of the
writes to only touch PCI_EXP_LNKCTL_ASPMC field which the driver itself
has been changing, leave the other fields untouched.

Suggested-by: Lukas Wunner <lukas@...ner.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
---
 drivers/net/wireless/ath/ath10k/pci.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
index a7f44f6335fb..d18dfb495194 100644
--- a/drivers/net/wireless/ath/ath10k/pci.c
+++ b/drivers/net/wireless/ath/ath10k/pci.c
@@ -1963,8 +1963,8 @@ 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_lnkctl_clear_and_set(ar_pci->pdev, 0,
+				  ar_pci->link_ctl & PCI_EXP_LNKCTL_ASPMC);
 
 	return 0;
 }
@@ -2821,8 +2821,8 @@ 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_lnkctl_clear_and_set(ar_pci->pdev,
+				  ar_pci->link_ctl & PCI_EXP_LNKCTL_ASPMC, 0);
 
 	/*
 	 * Bring the target up cleanly.
-- 
2.30.2