[PATCH 5.10 191/406] wifi: ath10k: Use RMW accessors for changing LNKCTL

Greg Kroah-Hartman
2023-09-17T19:31:38Z

From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

[ 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>
---
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 67e240327fb31..2c8f04b415c71 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;
}
@@ -2820,8 +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_capability_clear_word(ar_pci->pdev, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_ASPMC);

/*
* Bring the target up cleanly.
--
2.40.1