[PATCH v3 09/10] wifi: ath12k: Use RMW accessors for changing LNKCTL

Ilpo Järvinen
2023-06-20T13:50:11Z

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 do proper locking to avoid losing
concurrent updates to the register value. On restore, clear the ASPMC
field properly.

Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Acked-by: Kalle Valo <kvalo@kernel.org>
Cc: stable@vger.kernel.org
---
drivers/net/wireless/ath/ath12k/pci.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/pci.c b/drivers/net/wireless/ath/ath12k/pci.c
index 9f174daf324c..e1e45eb50f3e 100644
--- a/drivers/net/wireless/ath/ath12k/pci.c
+++ b/drivers/net/wireless/ath/ath12k/pci.c
@@ -794,8 +794,8 @@ static void ath12k_pci_aspm_disable(struct ath12k_pci *ab_pci)
u16_get_bits(ab_pci->link_ctl, PCI_EXP_LNKCTL_ASPM_L1));

/* disable L0s and L1 */
- pcie_capability_write_word(ab_pci->pdev, PCI_EXP_LNKCTL,
- ab_pci->link_ctl & ~PCI_EXP_LNKCTL_ASPMC);
+ pcie_capability_clear_word(ab_pci->pdev, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_ASPMC);

set_bit(ATH12K_PCI_ASPM_RESTORE, &ab_pci->flags);
}
@@ -803,8 +803,10 @@ static void ath12k_pci_aspm_disable(struct ath12k_pci *ab_pci)
static void ath12k_pci_aspm_restore(struct ath12k_pci *ab_pci)
{
if (test_and_clear_bit(ATH12K_PCI_ASPM_RESTORE, &ab_pci->flags))
- pcie_capability_write_word(ab_pci->pdev, PCI_EXP_LNKCTL,
- ab_pci->link_ctl);
+ pcie_capability_clear_and_set_word(ab_pci->pdev, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_ASPMC,
+ ab_pci->link_ctl &
+ PCI_EXP_LNKCTL_ASPMC);
}

static void ath12k_pci_kill_tasklets(struct ath12k_base *ab)
--
2.30.2