wifi: ath10k: Use RMW accessors for changing LNKCTL

[ Upstream commit f139492a09f15254fa261245cdbd65555cdf39e3 ]

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.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Fixes: 76d870ed09ab ("ath10k: enable ASPM")
Link: https://lore.kernel.org/r/20230717120503.15276-11-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Kalle Valo <kvalo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
index 07457eb9d4551f646bbb4862bb04970672cfae79..27200544162c712eb299b0e1750ccb0807a2b596 100644 (file)
--- a/drivers/net/wireless/ath/ath10k/pci.c
+++ b/drivers/net/wireless/ath/ath10k/pci.c
@@ -1661,8 +1661,9 @@ 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;
 }
@@ -2516,8 +2517,8 @@ 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.