Subject: RE: [PATCH net-next 1/1] r8169: enable RTL8125 ASPM L1.2

From: Hau <[email-masked]>
Date: Wed, 26 Jan 2022 15:03:52 +0000

> -----Original Message-----
> From: Heiner Kallweit [mailto:[email-masked]]
> Sent: Wednesday, January 26, 2022 9:47 PM
> To: Hau <[email-masked]>; [email-masked]
> Cc: nic_swsd <[email-masked]>; [email-masked]
> Subject: Re: [PATCH net-next 1/1] r8169: enable RTL8125 ASPM L1.2
> 
> On 26.01.2022 14:00, Hau wrote:
> >> On 24.01.2022 19:19, Chunhao Lin wrote:
> >>> This patch will enable RTL8125 ASPM L1.2 on the platforms that have
> >>> tested RTL8125 with ASPM L1.2 enabled.
> >>> Register mac ocp 0xc0b2 will help to identify if RTL8125 has been
> >>> tested on L1.2 enabled platform. If it is, this register will be set to 0xf.
> >>> If not, this register will be default value 0.
> >>>
> >>> Signed-off-by: Chunhao Lin <[email-masked]>
> >>> ---
> >>>  drivers/net/ethernet/realtek/r8169_main.c | 99
> >>> ++++++++++++++++++-----
> >>>  1 file changed, 79 insertions(+), 20 deletions(-)
> >>>
> >>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c
> >>> b/drivers/net/ethernet/realtek/r8169_main.c
> >>> index 19e2621e0645..b1e013969d4c 100644
> >>> --- a/drivers/net/ethernet/realtek/r8169_main.c
> >>> +++ b/drivers/net/ethernet/realtek/r8169_main.c
> >>> @@ -2238,21 +2238,6 @@ static void rtl_wol_enable_rx(struct
> >> rtl8169_private *tp)
> >>>  			AcceptBroadcast | AcceptMulticast |
> >> AcceptMyPhys);  }
> >>>
> >>> -static void rtl_prepare_power_down(struct rtl8169_private *tp) -{
> >>> -	if (tp->dash_type != RTL_DASH_NONE)
> >>> -		return;
> >>> -
> >>> -	if (tp->mac_version == RTL_GIGA_MAC_VER_32 ||
> >>> -	    tp->mac_version == RTL_GIGA_MAC_VER_33)
> >>> -		rtl_ephy_write(tp, 0x19, 0xff64);
> >>> -
> >>> -	if (device_may_wakeup(tp_to_dev(tp))) {
> >>> -		phy_speed_down(tp->phydev, false);
> >>> -		rtl_wol_enable_rx(tp);
> >>> -	}
> >>> -}
> >>> -
> >>>  static void rtl_init_rxcfg(struct rtl8169_private *tp)  {
> >>>  	switch (tp->mac_version) {
> >>> @@ -2650,6 +2635,34 @@ static void
> >>> rtl_pcie_state_l2l3_disable(struct
> >> rtl8169_private *tp)
> >>>  	RTL_W8(tp, Config3, RTL_R8(tp, Config3) & ~Rdy_to_L23);  }
> >>>
> >>> +static void rtl_disable_exit_l1(struct rtl8169_private *tp) {
> >>> +	/* Bits control which events trigger ASPM L1 exit:
> >>> +	 * Bit 12: rxdv
> >>> +	 * Bit 11: ltr_msg
> >>> +	 * Bit 10: txdma_poll
> >>> +	 * Bit  9: xadm
> >>> +	 * Bit  8: pktavi
> >>> +	 * Bit  7: txpla
> >>> +	 */
> >>> +	switch (tp->mac_version) {
> >>> +	case RTL_GIGA_MAC_VER_34 ... RTL_GIGA_MAC_VER_36:
> >>> +		rtl_eri_clear_bits(tp, 0xd4, 0x1f00);
> >>> +		break;
> >>> +	case RTL_GIGA_MAC_VER_37 ... RTL_GIGA_MAC_VER_38:
> >>> +		rtl_eri_clear_bits(tp, 0xd4, 0x0c00);
> >>> +		break;
> >>> +	case RTL_GIGA_MAC_VER_40 ... RTL_GIGA_MAC_VER_53:
> >>> +		rtl_eri_clear_bits(tp, 0xd4, 0x1f80);
> >>> +		break;
> >>> +	case RTL_GIGA_MAC_VER_60 ... RTL_GIGA_MAC_VER_63:
> >>> +		r8168_mac_ocp_modify(tp, 0xc0ac, 0x1f80, 0);
> >>> +		break;
> >>> +	default:
> >>> +		break;
> >>> +	}
> >>> +}
> >>> +
> >>>  static void rtl_enable_exit_l1(struct rtl8169_private *tp)  {
> >>>  	/* Bits control which events trigger ASPM L1 exit:
> >>> @@ -2692,6 +2705,33 @@ static void rtl_hw_aspm_clkreq_enable(struct
> >> rtl8169_private *tp, bool enable)
> >>>  	udelay(10);
> >>>  }
> >>>
> >>> +static void rtl_hw_aspm_l12_enable(struct rtl8169_private *tp, bool
> >>> +enable) {
> >>> +	/* Don't enable L1.2 in the chip if OS can't control ASPM */
> >>> +	if (enable && tp->aspm_manageable) {
> >>> +		r8168_mac_ocp_modify(tp, 0xe094, 0xff00, 0);
> >>> +		r8168_mac_ocp_modify(tp, 0xe092, 0x00ff, BIT(2));
> >>> +	} else {
> >>> +		r8168_mac_ocp_modify(tp, 0xe092, 0x00ff, 0);
> >>> +	}
> >>> +}
> >>> +
> >>> +static void rtl_prepare_power_down(struct rtl8169_private *tp) {
> >>> +	if (tp->dash_type != RTL_DASH_NONE)
> >>> +		return;
> >>> +
> >>> +	if (tp->mac_version == RTL_GIGA_MAC_VER_32 ||
> >>> +	    tp->mac_version == RTL_GIGA_MAC_VER_33)
> >>> +		rtl_ephy_write(tp, 0x19, 0xff64);
> >>> +
> >>> +	if (device_may_wakeup(tp_to_dev(tp))) {
> >>> +		rtl_disable_exit_l1(tp);
> >>> +		phy_speed_down(tp->phydev, false);
> >>> +		rtl_wol_enable_rx(tp);
> >>> +	}
> >>> +}
> >>> +
> >>>  static void rtl_set_fifo_size(struct rtl8169_private *tp, u16 rx_stat,
> >>>  			      u16 tx_stat, u16 rx_dyn, u16 tx_dyn)  { @@ -
> >> 3675,6 +3715,7
> >>> @@ static void rtl_hw_start_8125b(struct rtl8169_private *tp)
> >>>  	rtl_ephy_init(tp, e_info_8125b);
> >>>  	rtl_hw_start_8125_common(tp);
> >>>
> >>> +	rtl_hw_aspm_l12_enable(tp, true);
> >>>  	rtl_hw_aspm_clkreq_enable(tp, true);  }
> >>>
> >>> @@ -5255,6 +5296,20 @@ static void rtl_init_mac_address(struct
> >> rtl8169_private *tp)
> >>>  	rtl_rar_set(tp, mac_addr);
> >>>  }
> >>>
> >>> +/* mac ocp 0xc0b2 will help to identify if RTL8125 has been tested
> >>> + * on L1.2 enabled platform. If it is, this register will be set to 0xf.
> >>> + * If not, this register will be default value 0.
> >>> + */
> >>> +static bool rtl_platform_l12_enabled(struct rtl8169_private *tp) {
> >>> +	switch (tp->mac_version) {
> >>> +	case RTL_GIGA_MAC_VER_60 ... RTL_GIGA_MAC_VER_63:
> >>> +		return (r8168_mac_ocp_read(tp, 0xc0b2) & 0xf) ? true : false;
> >>> +	default:
> >>> +		return false;
> >>> +	}
> >>> +}
> >>> +
> >>>  static int rtl_init_one(struct pci_dev *pdev, const struct
> >>> pci_device_id *ent)  {
> >>>  	struct rtl8169_private *tp;
> >>> @@ -5333,11 +5388,15 @@ static int rtl_init_one(struct pci_dev
> >>> *pdev,
> >> const struct pci_device_id *ent)
> >>>  	 * Chips from RTL8168h partially have issues with L1.2, but seem
> >>>  	 * to work fine with L1 and L1.1.
> >>>  	 */
> >>> -	if (tp->mac_version >= RTL_GIGA_MAC_VER_45)
> >>> -		rc = pci_disable_link_state(pdev, PCIE_LINK_STATE_L1_2);
> >>> -	else
> >>> -		rc = pci_disable_link_state(pdev, PCIE_LINK_STATE_L1);
> >>> -	tp->aspm_manageable = !rc;
> >>> +	if (!rtl_platform_l12_enabled(tp)) {
> >>> +		if (tp->mac_version >= RTL_GIGA_MAC_VER_45)
> >>> +			rc = pci_disable_link_state(pdev,
> >> PCIE_LINK_STATE_L1_2);
> >>> +		else
> >>> +			rc = pci_disable_link_state(pdev,
> >> PCIE_LINK_STATE_L1);
> >>> +		tp->aspm_manageable = !rc;
> >>> +	} else {
> >>> +		tp->aspm_manageable = pcie_aspm_enabled(pdev);
> >>> +	}
> >>>
> >>>  	tp->dash_type = rtl_check_dash(tp);
> >>>
> >>
> >> Hi Hau,
> >>
> >> the following is a stripped-down version of the patch. Could you
> >> please check/test?
> > This patch is ok.
> > L1 substate lock can apply for both rtl8125a.rtl8125b.
> > if (enable && tp->aspm_manageable) {
> > 	RTL_W8(tp, Config5, RTL_R8(tp, Config5) | ASPM_en);
> > 	RTL_W8(tp, Config2, RTL_R8(tp, Config2) | ClkReqEn);
> >
> > 	if (tp->mac_version >= RTL_GIGA_MAC_VER_60) {
> > 		r8168_mac_ocp_modify(tp, 0xe094, 0xff00, 0);
> > 		r8168_mac_ocp_modify(tp, 0xe092, 0x00ff, BIT(2));
> > 	}
> > } else {
> > 	if (tp->mac_version >= RTL_GIGA_MAC_VER_60)
> > 		r8168_mac_ocp_modify(tp, 0xe092, 0x00ff, 0);
> >
> > 	RTL_W8(tp, Config2, RTL_R8(tp, Config2) & ~ClkReqEn);
> > 	RTL_W8(tp, Config5, RTL_R8(tp, Config5) & ~ASPM_en); }
> >
> >> If function rtl_disable_exit_l1() is actually needed, I'd prefer to
> >> add it in a separate patch (to facilitate bisecting).
> >>
> > If exit l1 mask is enabled, hardware will prone to exit l1. That will
> > prevent hardware from entering l1 substate. So It needs to disable l1
> > exist mask when device go to d3 state for entering l1 substate..
> >
> My understanding of PCI power management may be incomplete, but:
> If a device goes to D3, then doesn't the bus go to L2/L3?
> L1 exit criteria would be irrelevant then.
Your understanding is correct.
D3 is divided to two substate, D3hot and D3cold. D3cold will enter L2/L3.
D3hot may enter L1 or L2/L3 ready.  In D3hot case, enable exit l1 mask will
prevent hardware from entering PM L1. That is our hardware issue.
So we disable exit l1 mask before hardware enter D3.

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