linux-kernel - [PATCH 4/6] wifi: ath12k: Use pci_{enable/disable}_link_state() APIs to enable/disable ASPM states

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Message-Id: <20250716-ath-aspm-fix-v1-4-dd3e62c1b692@oss.qualcomm.com>
Date: Wed, 16 Jul 2025 18:26:23 +0530
From: Manivannan Sadhasivam via B4 Relay <devnull+manivannan.sadhasivam.oss.qualcomm.com@...nel.org>
To: Jeff Johnson <jjohnson@...nel.org>, 
 Manivannan Sadhasivam <mani@...nel.org>, 
 Lorenzo Pieralisi <lpieralisi@...nel.org>, 
 Krzysztof Wilczyński <kwilczynski@...nel.org>, 
 Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>, 
 Nirmal Patel <nirmal.patel@...ux.intel.com>, 
 Jonathan Derrick <jonathan.derrick@...ux.dev>
Cc: linux-wireless@...r.kernel.org, linux-kernel@...r.kernel.org, 
 ath12k@...ts.infradead.org, ath11k@...ts.infradead.org, 
 ath10k@...ts.infradead.org, Bjorn Helgaas <helgaas@...nel.org>, 
 ilpo.jarvinen@...ux.intel.com, linux-arm-msm@...r.kernel.org, 
 linux-pci@...r.kernel.org, 
 Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>, 
 Manivannan Sadhasivam <manivannan.sadhasivam@....qualcomm.com>, 
 Qiang Yu <qiang.yu@....qualcomm.com>
Subject: [PATCH 4/6] wifi: ath12k: Use pci_{enable/disable}_link_state()
 APIs to enable/disable ASPM states

From: Manivannan Sadhasivam <manivannan.sadhasivam@....qualcomm.com>

It is not recommended to enable/disable the ASPM states on the back of the
PCI core directly using the LNKCTL register. It will break the PCI core's
knowledge about the device ASPM states. So use the APIs exposed by the PCI
core to enable/disable ASPM states.

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Reported-by: Qiang Yu <qiang.yu@....qualcomm.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@....qualcomm.com>
---
 drivers/net/wireless/ath/ath.h        | 14 ++++++++++++++
 drivers/net/wireless/ath/ath12k/pci.c | 10 ++++------
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/ath/ath.h b/drivers/net/wireless/ath/ath.h
index 34654f710d8a1e63f65a47d4602e2035262a4d9e..ef685123b66bf4f41428fec67c1967f242a9ef27 100644
--- a/drivers/net/wireless/ath/ath.h
+++ b/drivers/net/wireless/ath/ath.h
@@ -21,6 +21,8 @@
 #include <linux/skbuff.h>
 #include <linux/if_ether.h>
 #include <linux/spinlock.h>
+#include <linux/pci.h>
+#include <linux/pci_regs.h>
 #include <net/mac80211.h>
 
 /*
@@ -336,4 +338,16 @@ static inline const char *ath_bus_type_to_string(enum ath_bus_type bustype)
 	return ath_bus_type_strings[bustype];
 }
 
+static inline int ath_pci_aspm_state(u16 lnkctl)
+{
+	int state = 0;
+
+	if (lnkctl & PCI_EXP_LNKCTL_ASPM_L0S)
+		state |= PCIE_LINK_STATE_L0S;
+	if (lnkctl & PCI_EXP_LNKCTL_ASPM_L1)
+		state |= PCIE_LINK_STATE_L1;
+
+	return state;
+}
+
 #endif /* ATH_H */
diff --git a/drivers/net/wireless/ath/ath12k/pci.c b/drivers/net/wireless/ath/ath12k/pci.c
index 489d546390fcdab8f615cc9184006a958d9f140a..a5e11509e3ab8faad6638ff78ce6a8a5e9c3cbbd 100644
--- a/drivers/net/wireless/ath/ath12k/pci.c
+++ b/drivers/net/wireless/ath/ath12k/pci.c
@@ -16,6 +16,8 @@
 #include "mhi.h"
 #include "debug.h"
 
+#include "../ath.h"
+
 #define ATH12K_PCI_BAR_NUM		0
 #define ATH12K_PCI_DMA_MASK		36
 
@@ -928,8 +930,7 @@ 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_clear_word(ab_pci->pdev, PCI_EXP_LNKCTL,
-				   PCI_EXP_LNKCTL_ASPMC);
+	pci_disable_link_state(ab_pci->pdev, PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1);
 
 	set_bit(ATH12K_PCI_ASPM_RESTORE, &ab_pci->flags);
 }
@@ -958,10 +959,7 @@ static void ath12k_pci_aspm_restore(struct ath12k_pci *ab_pci)
 {
 	if (ab_pci->ab->hw_params->supports_aspm &&
 	    test_and_clear_bit(ATH12K_PCI_ASPM_RESTORE, &ab_pci->flags))
-		pcie_capability_clear_and_set_word(ab_pci->pdev, PCI_EXP_LNKCTL,
-						   PCI_EXP_LNKCTL_ASPMC,
-						   ab_pci->link_ctl &
-						   PCI_EXP_LNKCTL_ASPMC);
+		pci_enable_link_state(ab_pci->pdev, ath_pci_aspm_state(ab_pci->link_ctl));
 }
 
 static void ath12k_pci_cancel_workqueue(struct ath12k_base *ab)

-- 
2.45.2