RE: [EXT] Re: [PATCH v3 net 2/2] net: stmmac: dwmac-imx: pause the TXC clock in fixed-link

[Shenwei Wang]

> -----Original Message-----
> From: Johannes Zink <j.zink@xxxxxxxxxxxxxx>
> Sent: Wednesday, August 2, 2023 9:40 AM
> To: Shenwei Wang <shenwei.wang@xxxxxxx>; Russell King
> <linux@xxxxxxxxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; Eric
> Dumazet <edumazet@xxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Paolo
> Abeni <pabeni@xxxxxxxxxx>; Maxime Coquelin
> <mcoquelin.stm32@xxxxxxxxx>; Shawn Guo <shawnguo@xxxxxxxxxx>; Sascha
> Hauer <s.hauer@xxxxxxxxxxxxxx>; Neil Armstrong <neil.armstrong@xxxxxxxxxx>;
> Kevin Hilman <khilman@xxxxxxxxxxxx>; Vinod Koul <vkoul@xxxxxxxxxx>; Chen-
> Yu Tsai <wens@xxxxxxxx>; Jernej Skrabec <jernej.skrabec@xxxxxxxxx>; Samuel
> Holland <samuel@xxxxxxxxxxxx>
> Cc: Giuseppe Cavallaro <peppe.cavallaro@xxxxxx>; Alexandre Torgue
> <alexandre.torgue@xxxxxxxxxxx>; Jose Abreu <joabreu@xxxxxxxxxxxx>;
> Pengutronix Kernel Team <kernel@xxxxxxxxxxxxxx>; Fabio Estevam
> <festevam@xxxxxxxxx>; dl-linux-imx <linux-imx@xxxxxxx>; Jerome Brunet
> <jbrunet@xxxxxxxxxxxx>; Martin Blumenstingl
> <martin.blumenstingl@xxxxxxxxxxxxxx>; Bhupesh Sharma
> <bhupesh.sharma@xxxxxxxxxx>; Nobuhiro Iwamatsu
> <nobuhiro1.iwamatsu@xxxxxxxxxxxxx>; Simon Horman
> <simon.horman@xxxxxxxxxxxx>; Andrew Halaney <ahalaney@xxxxxxxxxx>;
> Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>; Wong Vee Khee
> <veekhee@xxxxxxxxx>; Revanth Kumar Uppala <ruppala@xxxxxxxxxx>; Jochen
> Henneberg <jh@xxxxxxxxxxxxxxxxxxxxxxxxxx>; netdev@xxxxxxxxxxxxxxx; linux-
> stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; linux-amlogic@xxxxxxxxxxxxxxxxxxx;
> imx@xxxxxxxxxxxxxxx; Frank Li <frank.li@xxxxxxx>
> Subject: Re: [EXT] Re: [PATCH v3 net 2/2] net: stmmac: dwmac-imx: pause the
> TXC clock in fixed-link
>
> Caution: This is an external email. Please take care when clicking links or
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>
>
> Hi Shenwei,
>
> On 8/2/23 16:27, Shenwei Wang wrote:
> >
> >
> >> -----Original Message-----
> >> From: Johannes Zink <j.zink@xxxxxxxxxxxxxx>
> >> Sent: Wednesday, August 2, 2023 1:26 AM
> >> To: Shenwei Wang <shenwei.wang@xxxxxxx>; Russell King
> >> <linux@xxxxxxxxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; Eric
> >> Dumazet <edumazet@xxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>;
> >> Paolo Abeni <pabeni@xxxxxxxxxx>; Maxime Coquelin
> >> <mcoquelin.stm32@xxxxxxxxx>; Shawn Guo <shawnguo@xxxxxxxxxx>;
> Sascha
> >> Hauer <s.hauer@xxxxxxxxxxxxxx>; Neil Armstrong
> >> <neil.armstrong@xxxxxxxxxx>; Kevin Hilman <khilman@xxxxxxxxxxxx>;
> >> Vinod Koul <vkoul@xxxxxxxxxx>; Chen- Yu Tsai <wens@xxxxxxxx>; Jernej
> >> Skrabec <jernej.skrabec@xxxxxxxxx>; Samuel Holland
> >> <samuel@xxxxxxxxxxxx>
> >> Cc: Giuseppe Cavallaro <peppe.cavallaro@xxxxxx>; Alexandre Torgue
> >> <alexandre.torgue@xxxxxxxxxxx>; Jose Abreu <joabreu@xxxxxxxxxxxx>;
> >> Pengutronix Kernel Team <kernel@xxxxxxxxxxxxxx>; Fabio Estevam
> >> <festevam@xxxxxxxxx>; dl-linux-imx <linux-imx@xxxxxxx>; Jerome Brunet
> >> <jbrunet@xxxxxxxxxxxx>; Martin Blumenstingl
> >> <martin.blumenstingl@xxxxxxxxxxxxxx>; Bhupesh Sharma
> >> <bhupesh.sharma@xxxxxxxxxx>; Nobuhiro Iwamatsu
> >> <nobuhiro1.iwamatsu@xxxxxxxxxxxxx>; Simon Horman
> >> <simon.horman@xxxxxxxxxxxx>; Andrew Halaney <ahalaney@xxxxxxxxxx>;
> >> Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>; Wong Vee Khee
> >> <veekhee@xxxxxxxxx>; Revanth Kumar Uppala <ruppala@xxxxxxxxxx>;
> >> Jochen Henneberg <jh@xxxxxxxxxxxxxxxxxxxxxxxxxx>;
> >> netdev@xxxxxxxxxxxxxxx; linux- stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx;
> >> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> >> linux-kernel@xxxxxxxxxxxxxxx; linux-amlogic@xxxxxxxxxxxxxxxxxxx;
> >> imx@xxxxxxxxxxxxxxx; Frank Li <frank.li@xxxxxxx>
> >> Subject: Re: [EXT] Re: [PATCH v3 net 2/2] net: stmmac: dwmac-imx:
> >> pause the TXC clock in fixed-link
> >>
> >> Caution: This is an external email. Please take care when clicking
> >> links or opening attachments. When in doubt, report the message using
> >> the 'Report this email' button
> >>
> >>
> >> Hi Shenwei,
> >>
> >> On 8/1/23 19:10, Shenwei Wang wrote:
> >>>
> >>>
> >>>> -----Original Message-----
> >>>> From: Johannes Zink <j.zink@xxxxxxxxxxxxxx>
> >>>> Sent: Tuesday, August 1, 2023 7:48 AM
> >>>> To: Shenwei Wang <shenwei.wang@xxxxxxx>; Russell King
> >>>> <linux@xxxxxxxxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>;
> >>>> Eric Dumazet <edumazet@xxxxxxxxxx>; Jakub Kicinski
> >>>> <kuba@xxxxxxxxxx>; Paolo Abeni <pabeni@xxxxxxxxxx>; Maxime Coquelin
> >>>> <mcoquelin.stm32@xxxxxxxxx>; Shawn Guo <shawnguo@xxxxxxxxxx>;
> >> Sascha
> >>>> Hauer <s.hauer@xxxxxxxxxxxxxx>; Neil Armstrong
> >>>> <neil.armstrong@xxxxxxxxxx>; Kevin Hilman <khilman@xxxxxxxxxxxx>;
> >>>> Vinod Koul <vkoul@xxxxxxxxxx>; Chen- Yu Tsai <wens@xxxxxxxx>;
> >>>> Jernej Skrabec <jernej.skrabec@xxxxxxxxx>; Samuel Holland
> >>>> <samuel@xxxxxxxxxxxx>
> >>>> Cc: Giuseppe Cavallaro <peppe.cavallaro@xxxxxx>; Alexandre Torgue
> >>>> <alexandre.torgue@xxxxxxxxxxx>; Jose Abreu <joabreu@xxxxxxxxxxxx>;
> >>>> Pengutronix Kernel Team <kernel@xxxxxxxxxxxxxx>; Fabio Estevam
> >>>> <festevam@xxxxxxxxx>; dl-linux-imx <linux-imx@xxxxxxx>; Jerome
> >>>> Brunet <jbrunet@xxxxxxxxxxxx>; Martin Blumenstingl
> >>>> <martin.blumenstingl@xxxxxxxxxxxxxx>; Bhupesh Sharma
> >>>> <bhupesh.sharma@xxxxxxxxxx>; Nobuhiro Iwamatsu
> >>>> <nobuhiro1.iwamatsu@xxxxxxxxxxxxx>; Simon Horman
> >>>> <simon.horman@xxxxxxxxxxxx>; Andrew Halaney
> <ahalaney@xxxxxxxxxx>;
> >>>> Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>; Wong Vee Khee
> >>>> <veekhee@xxxxxxxxx>; Revanth Kumar Uppala <ruppala@xxxxxxxxxx>;
> >>>> Jochen Henneberg <jh@xxxxxxxxxxxxxxxxxxxxxxxxxx>;
> >>>> netdev@xxxxxxxxxxxxxxx; linux- stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx;
> >>>> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> >>>> linux-kernel@xxxxxxxxxxxxxxx; linux-amlogic@xxxxxxxxxxxxxxxxxxx;
> >>>> imx@xxxxxxxxxxxxxxx; Frank Li <frank.li@xxxxxxx>
> >>>> Subject: [EXT] Re: [PATCH v3 net 2/2] net: stmmac: dwmac-imx: pause
> >>>> the TXC clock in fixed-link
> >>>>
> >>>> Caution: This is an external email. Please take care when clicking
> >>>> links or opening attachments. When in doubt, report the message
> >>>> using the 'Report this email' button
> >>>>
> >>>>
> >>>> Hi Shenwei,
> >>>>
> >>>> thanks for your patch.
> >>>>
> >>>> On 7/31/23 18:19, Shenwei Wang wrote:
> >>>>> When using a fixed-link setup, certain devices like the SJA1105
> >>>>> require a small pause in the TXC clock line to enable their
> >>>>> internal tunable delay line (TDL).
> >>>>
> >>>> If this is only required for some devices, is it safe to enforce
> >>>> this behaviour unconditionally for any kind of fixed link devices
> >>>> connected to the MX93 EQOS or could this possibly break for other devices?
> >>>>
> >>>
> >>> It won't impact normal devices. The link layer hasn't built up yet.
> >>>
> >>
> >> As Russel suggested in [1] - maybe you could rephrase your commit
> >> message for your v4 to point this out to future reviewers (apparently
> >> multiple people have had questions about this...)  and have this fact
> >> also recorded in the git log later on.
> >>
> >
> > Okay.
> >
> >> Also: does this only apply to i.MX93, or would we have to test and
> >> enable it on e.g. i.MX8MP as well?
> >>
> >
> > Yes, it is required when the EQOS MAC is selected. However, this patch
> > just enables The feature on i.MX93.
>
> If this behaviour is required on all EQOS, I think the name
> imx_dwmac_fix_speed_mx93() is misleading. It should either be
> imx_dwmac_fix_speed() if applicable to all imx implementations, or
> dwmac_fix_speed() (and moved to a non-gluecode file) if applicable for all
> implementations in general.
>

It has the general fix_speed function there named imx_dwmac_fix_speed.
This one is the special for this mx93 fix.

Thanks,
Shenwei


> You can then add a second patch for enabling it for the i.mx93 in the gluecode
> driver.
>
> Johannes
>
>
> >
> > Thanks,
> > Shenwei
> >
> >> Thanks
> >> Johannes
> >>
> >> [1] ZMk/xqRP67zXHNrf@xxxxxxxxxxxxxxxxxxxxx
> >>
> >>
> >>> Thanks,
> >>> Shenwei
> >>>
> >>>> Best regards
> >>>> Johannes
> >>>>
> >>>>>
> >>>>> To satisfy this requirement, this patch temporarily disables the
> >>>>> TX clock, and restarts it after a required period. This provides
> >>>>> the required silent interval on the clock line for SJA1105 to
> >>>>> complete the frequency transition and enable the internal TDLs.
> >>>>>
> >>>>> So far we have only enabled this feature on the i.MX93 platform.
> >>>>>
> >>>>> Signed-off-by: Shenwei Wang <shenwei.wang@xxxxxxx>
> >>>>> Reviewed-by: Frank Li <frank.li@xxxxxxx>
> >>>>> ---
> >>>>>     .../net/ethernet/stmicro/stmmac/dwmac-imx.c   | 42
> >> +++++++++++++++++++
> >>>>>     1 file changed, 42 insertions(+)
> >>>>>
> >>>>> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-imx.c
> >>>>> b/drivers/net/ethernet/stmicro/stmmac/dwmac-imx.c
> >>>>> index 53ee5a42c071..2e4173d099f3 100644
> >>>>> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-imx.c
> >>>>> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-imx.c
> >>>>> @@ -32,6 +32,7 @@
> >>>>>     #define GPR_ENET_QOS_RGMII_EN               (0x1 << 21)
> >>>>>
> >>>>>     #define MX93_GPR_ENET_QOS_INTF_MODE_MASK    GENMASK(3, 0)
> >>>>> +#define MX93_GPR_ENET_QOS_INTF_MASK          GENMASK(3, 1)
> >>>>>     #define MX93_GPR_ENET_QOS_INTF_SEL_MII              (0x0 << 1)
> >>>>>     #define MX93_GPR_ENET_QOS_INTF_SEL_RMII             (0x4 << 1)
> >>>>>     #define MX93_GPR_ENET_QOS_INTF_SEL_RGMII    (0x1 << 1)
> >>>>> @@ -40,6 +41,7 @@
> >>>>>     #define DMA_BUS_MODE                        0x00001000
> >>>>>     #define DMA_BUS_MODE_SFT_RESET              (0x1 << 0)
> >>>>>     #define RMII_RESET_SPEED            (0x3 << 14)
> >>>>> +#define CTRL_SPEED_MASK                      GENMASK(15, 14)
> >>>>>
> >>>>>     struct imx_dwmac_ops {
> >>>>>         u32 addr_width;
> >>>>> @@ -56,6 +58,7 @@ struct imx_priv_data {
> >>>>>         struct regmap *intf_regmap;
> >>>>>         u32 intf_reg_off;
> >>>>>         bool rmii_refclk_ext;
> >>>>> +     void __iomem *base_addr;
> >>>>>
> >>>>>         const struct imx_dwmac_ops *ops;
> >>>>>         struct plat_stmmacenet_data *plat_dat; @@ -212,6 +215,42
> >>>>> @@ static void imx_dwmac_fix_speed(void *priv, uint speed, uint mode)
> >>>>>                 dev_err(dwmac->dev, "failed to set tx rate %lu\n", rate);
> >>>>>     }
> >>>>>
> >>>>> +static void imx_dwmac_fix_speed_mx93(void *priv, uint speed, uint
> >>>>> +mode) {
> >>>>> +     struct imx_priv_data *dwmac = priv;
> >>>>> +     int ctrl, old_ctrl, iface;
> >>>>> +
> >>>>> +     imx_dwmac_fix_speed(priv, speed, mode);
> >>>>> +
> >>>>> +     if (!dwmac || mode != MLO_AN_FIXED)
> >>>>> +             return;
> >>>>> +
> >>>>> +     if (regmap_read(dwmac->intf_regmap, dwmac->intf_reg_off, &iface))
> >>>>> +             return;
> >>>>> +
> >>>>> +     iface &= MX93_GPR_ENET_QOS_INTF_MASK;
> >>>>> +     if (iface != MX93_GPR_ENET_QOS_INTF_SEL_RGMII)
> >>>>> +             return;
> >>>>> +
> >>>>> +     old_ctrl = readl(dwmac->base_addr + MAC_CTRL_REG);
> >>>>> +     ctrl = old_ctrl & ~CTRL_SPEED_MASK;
> >>>>> +     regmap_update_bits(dwmac->intf_regmap, dwmac->intf_reg_off,
> >>>>> +                        MX93_GPR_ENET_QOS_INTF_MODE_MASK, 0);
> >>>>> +     writel(ctrl, dwmac->base_addr + MAC_CTRL_REG);
> >>>>> +
> >>>>> +     /* Ensure the settings for CTRL are applied and avoid CPU/Compiler
> >>>>> +      * reordering.
> >>>>> +      */
> >>>>> +     wmb();
> >>>>> +
> >>>>> +     usleep_range(10, 20);
> >>>>> +     iface |= MX93_GPR_ENET_QOS_CLK_GEN_EN;
> >>>>> +     regmap_update_bits(dwmac->intf_regmap, dwmac->intf_reg_off,
> >>>>> +                        MX93_GPR_ENET_QOS_INTF_MODE_MASK, iface);
> >>>>> +
> >>>>> +     writel(old_ctrl, dwmac->base_addr + MAC_CTRL_REG); }
> >>>>> +
> >>>>>     static int imx_dwmac_mx93_reset(void *priv, void __iomem *ioaddr)
> >>>>>     {
> >>>>>         struct plat_stmmacenet_data *plat_dat = priv; @@ -317,8
> >>>>> +356,11 @@ static int imx_dwmac_probe(struct platform_device
> >>>>> +*pdev)
> >>>>>         plat_dat->exit = imx_dwmac_exit;
> >>>>>         plat_dat->clks_config = imx_dwmac_clks_config;
> >>>>>         plat_dat->fix_mac_speed = imx_dwmac_fix_speed;
> >>>>> +     if (of_machine_is_compatible("fsl,imx93"))
> >>>>> +             plat_dat->fix_mac_speed = imx_dwmac_fix_speed_mx93;
> >>>>>         plat_dat->bsp_priv = dwmac;
> >>>>>         dwmac->plat_dat = plat_dat;
> >>>>> +     dwmac->base_addr = stmmac_res.addr;
> >>>>>
> >>>>>         ret = imx_dwmac_clks_config(dwmac, true);
> >>>>>         if (ret)
> >>>>
> >>>> --
> >>>> Pengutronix e.K.                | Johannes Zink                  |
> >>>> Steuerwalder Str. 21            |
> >>>> https://www/
> >>>> .pe%2F&data=05%7C01%7Cshenwei.wang%40nxp.com%7Ccfd142f0d60a4
> 61
> >> ee01408
> >>>>
> >>
> db9321578d%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63826554
> >> 36335
> >>>>
> >>
> 61986%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luM
> >> zIiLCJ
> >>>>
> >>
> BTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=CV10o1M%2BOj
> >> DPOaH5C
> >>>> y%2Fka%2B0aOMs0IaVapMH7aa3RnTI%3D&reserved=0
> >>>>
> >>
> ngutronix.de%2F&data=05%7C01%7Cshenwei.wang%40nxp.com%7C761fbb75c
> >>>>
> >>
> 1c24cfe091508db928d8ade%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C
> >>>>
> >>
> 0%7C638264908852977732%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjA
> >>>>
> >>
> wMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%
> >>>>
> >>
> 7C&sdata=2l2zNfIaNnRJENmERehNae8g%2F%2BQqlxD2YRx7ksY2X%2BE%3D&r
> >>>> eserved=0    |
> >>>> 31137 Hildesheim, Germany       | Phone: +49-5121-206917-0       |
> >>>> Amtsgericht Hildesheim, HRA 2686| Fax:   +49-5121-206917-5555    |
> >>>
> >>>
> >>
> >> --
> >> Pengutronix e.K.                | Johannes Zink                  |
> >> Steuerwalder Str. 21            |
> >> https://www/
> >> .pe%2F&data=05%7C01%7Cshenwei.wang%40nxp.com%7Cdc64404f8c2c4e
> b87a7808
> >>
> db93666ec9%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63826584
> 03801
> >>
> 74614%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luM
> zIiLCJ
> >>
> BTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=oxLnb3ppqjhMti
> cQH7P
> >> lfRbIlYJ2R1Z8Tg7Bz2vC%2F%2Bc%3D&reserved=0
> >>
> ngutronix.de%2F&data=05%7C01%7Cshenwei.wang%40nxp.com%7Ccfd142f0d
> >>
> 60a461ee01408db9321578d%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7
> >>
> C0%7C638265543633561986%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLj
> >>
> AwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C
> >> %7C&sdata=yKzNPsHqD%2FxU%2FRmzLn4JSQjmuT9tU8SabLxHyGTTmms%3
> D&r
> >> eserved=0    |
> >> 31137 Hildesheim, Germany       | Phone: +49-5121-206917-0       |
> >> Amtsgericht Hildesheim, HRA 2686| Fax:   +49-5121-206917-5555    |
> >
> >
>
> --
> Pengutronix e.K.                | Johannes Zink                  |
> Steuerwalder Str. 21            |
> https://www.pe/
> ngutronix.de%2F&data=05%7C01%7Cshenwei.wang%40nxp.com%7Cdc64404f8
> c2c4eb87a7808db93666ec9%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7
> C0%7C638265840380174614%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLj
> AwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C
> %7C&sdata=r8tFe0Ts3ev2c7lg3MK0Qc40101d7W%2BEwnpmvMDwjho%3D&res
> erved=0    |
> 31137 Hildesheim, Germany       | Phone: +49-5121-206917-0       |
> Amtsgericht Hildesheim, HRA 2686| Fax:   +49-5121-206917-5555    |