On Mon, Jul 21, 2025 at 11:04:10AM GMT, Ilpo Järvinen wrote:
> On Wed, 16 Jul 2025, Manivannan Sadhasivam via B4 Relay wrote:
>
> > From: Manivannan Sadhasivam <[email protected]>
> >
> > 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 <[email protected]>
> > Signed-off-by: Manivannan Sadhasivam
> > <[email protected]>
> > ---
> > 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.
>
Ack
> >
> > 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 thought about it, but since this driver doesn't necessarily enable ASPM for
all the devices it supports, I didn't add the dependency. But looking at it
again, I think makes sense to add the dependency since the driver cannot work
reliably without disabling ASPM (for the supported devices).
- Mani
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