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

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

On Wed, 16 Jul 2025, Manivannan Sadhasivam via B4 Relay wrote:

> From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.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@oss.qualcomm.com>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.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);

I'd remove to comment too as the code is self-explanatory after this 
change.

>  
>  	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)

As you now depend on ASPM driver being there, these should also add to 
Kconfig:

depends on PCIEASPM

-- 
 i.