Date: Mon, 13 May 2024 20:42:58 +0800
From: Huacai Chen <chenhuacai@...nel.org>
To: Yanteng Si <siyanteng@...ngson.cn>
Cc: Serge Semin <fancer.lancer@...il.com>, andrew@...n.ch, hkallweit1@...il.com, 
	peppe.cavallaro@...com, alexandre.torgue@...s.st.com, joabreu@...opsys.com, 
	Jose.Abreu@...opsys.com, linux@...linux.org.uk, guyinggang@...ngson.cn, 
	netdev@...r.kernel.org, chris.chenfeiyang@...il.com, siyanteng01@...il.com
Subject: Re: [PATCH net-next v12 06/15] net: stmmac: dwmac-loongson: Split up
 the platform data initialization

On Mon, May 13, 2024 at 7:07 PM Yanteng Si <siyanteng@...ngson.cn> wrote:
>
>
> 在 2024/5/4 02:08, Serge Semin 写道:
> >> [PATCH net-next v12 06/15] net: stmmac: dwmac-loongson: Split up the platform data initialization
> > Please convert the subject to being more specific, like this:
> >
> > net: stmmac: dwmac-loongson: Detach GMAC-specific platform data init
> >
> > On Thu, Apr 25, 2024 at 09:04:37PM +0800, Yanteng Si wrote:
> >> Based on IP core classification, loongson has two types of network
> > What is the real company name? At least start the name with the
> > capital letter.
> > * everywhere
> OK,  LOONGSON
> >
> >> devices: GMAC and GNET. GMAC's ip_core id is 0x35/0x37, while GNET's
> >> ip_core id is 0x37/0x10.
> > s/ip_core/IP-core
> >
> > Once again the IP-core ID isn't _hex_, but a number of the format:
> > "v+Major.Minor"
> > so use the _real_ IP-core version number everywhere. Note mentioning
> > that some of your GNET device has the GMAC_VERSION.SNPSVER hardwired
> > to 0x10 is completely redundant in this and many other context. The
> > only place where it's relevant is the patch(es) where you have the
> > Snps ID override.
> OK.
> >
> >> Device tables:
> >>
> >> device    type    pci_id    snps_id    channel
> >> ls2k1000  gmac    7a03      0x35/0x37   1
> >> ls7a1000  gmac    7a03      0x35/0x37   1
> >> ls2k2000  gnet    7a13      0x10        8
> >> ls7a2000  gnet    7a13      0x37        1
> > s/gmac/GMAC
> > s/gnet/GNET
> > s/pci_id/PCI Dev ID
> > s/snsp_id/Synopys Version
> > s/channels/DMA-channels
> > s/ls2k/LS2K
> > s/ls7a/LS7A
> >
> > * everywhere
> OK.
> >
> >> The GMAC device only has a MAC chip inside and needs an
> >> external PHY chip;
> >>
> >> To later distinguish 8-channel gnet devices from single-channel
> >> gnet/gmac devices, move rx_queues_to_use loongson_default_data
> >> to loongson_dwmac_probe(). Also move mac_interface to
> >> loongson_default_data().
> > Again. This is only a part of the reason why you need this change.
> > The main reason is to provide the two-leveled platform data init
> > functions: fist one is the common method initializing the data common
> > for both GMAC and GNET, second one is the device-specific data
> > initializer.
> >
> > To sum up I would change the commit log to something like this:
> >
> > "Loongson delivers two types of the network devices: Loongson GMAC and
> > Loongson GNET in the framework of four CPU/Chipsets revisions:
> >
> >     Chip             Network  PCI Dev ID   Synopys Version   DMA-channel
> > LS2K1000 CPU         GMAC      0x7a03       v3.50a/v3.73a        1
> > LS7A1000 Chipset     GMAC      0x7a03       v3.50a/v3.73a        1
> > LS2K2000 CPU         GNET      0x7a13          v3.73a            8
> > LS7A2000 Chipset     GNET      0x7a13          v3.73a            1
> >
> > The driver currently supports the chips with the Loongson GMAC network
> > device. As a preparation before adding the Loongson GNET support
> > detach the Loongson GMAC-specific platform data initializations to the
> > loongson_gmac_data() method and preserve the common settings in the
> > loongson_default_data().
> >
> > While at it drop the return value statement from the
> > loongson_default_data() method as redundant."
> OK, Thanks!
> >
> >> Signed-off-by: Feiyang Chen <chenfeiyang@...ngson.cn>
> >> Signed-off-by: Yinggang Gu <guyinggang@...ngson.cn>
> >> Signed-off-by: Yanteng Si <siyanteng@...ngson.cn>
> >> ---
> >>   .../ethernet/stmicro/stmmac/dwmac-loongson.c  | 20 ++++++++++++-------
> >>   1 file changed, 13 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c
> >> index 4e0838db4259..904e288d0be0 100644
> >> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c
> >> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c
> >> @@ -11,22 +11,20 @@
> >>
> >>   #define PCI_DEVICE_ID_LOONGSON_GMAC        0x7a03
> >>
> >> -static int loongson_default_data(struct plat_stmmacenet_data *plat)
> >> +static void loongson_default_data(struct plat_stmmacenet_data *plat)
> >>   {
> >>      plat->clk_csr = 2;      /* clk_csr_i = 20-35MHz & MDC = clk_csr_i/16 */
> >>      plat->has_gmac = 1;
> >>      plat->force_sf_dma_mode = 1;
> >>
> >> +    plat->mac_interface = PHY_INTERFACE_MODE_GMII;
> >> +
> > I double-checked this part in my HW and in the databooks. DW GMAC with
> > _RGMII_ PHY-interfaces can't be equipped with a PCS (STMMAC driver is
> > wrong in considering otherwise at least in the Auto-negotiation part).
> > PCS is only available for the RTI, RTBI and SGMII interfaces.
> >
> > You can double-check that by checking out the DMA_HW_FEATURE.PCSSEL
> > flag state. I'll be surprised if it's set in your case. If it isn't
> > then either drop the plat_stmmacenet_data::mac_interface
> > initialization or (as Russell suggested) initialize it with
> > PHY_INTERFACE_MODE_NA. But do that in a separate pre-requisite patch!
> OK.
> >
> >>      /* Set default value for unicast filter entries */
> >>      plat->unicast_filter_entries = 1;
> >>
> >>      /* Set the maxmtu to a default of JUMBO_LEN */
> >>      plat->maxmtu = JUMBO_LEN;
> >>
> >> -    /* Set default number of RX and TX queues to use */
> >> -    plat->tx_queues_to_use = 1;
> >> -    plat->rx_queues_to_use = 1;
> >> -
> >>      /* Disable Priority config by default */
> >>      plat->tx_queues_cfg[0].use_prio = false;
> >>      plat->rx_queues_cfg[0].use_prio = false;
> >> @@ -41,6 +39,12 @@ static int loongson_default_data(struct plat_stmmacenet_data *plat)
> >>      plat->dma_cfg->pblx8 = true;
> >>
> >>      plat->multicast_filter_bins = 256;
> >> +}
> >> +
> >> +static int loongson_gmac_data(struct plat_stmmacenet_data *plat)
> >> +{
> >> +    loongson_default_data(plat);
> >> +
> >>      return 0;
> >>   }
> >>
> >> @@ -109,11 +113,10 @@ static int loongson_dwmac_probe(struct pci_dev *pdev, const struct pci_device_id
> >>      }
> >>
> >>      plat->phy_interface = phy_mode;
> >> -    plat->mac_interface = PHY_INTERFACE_MODE_GMII;
> >>
> >>      pci_set_master(pdev);
> >>
> >> -    loongson_default_data(plat);
> >> +    loongson_gmac_data(plat);
> >>      pci_enable_msi(pdev);
> >>      memset(&res, 0, sizeof(res));
> >>      res.addr = pcim_iomap_table(pdev)[0];
> >> @@ -138,6 +141,9 @@ static int loongson_dwmac_probe(struct pci_dev *pdev, const struct pci_device_id
> >>              goto err_disable_msi;
> >>      }
> >>
> >> +    plat->tx_queues_to_use = 1;
> >> +    plat->rx_queues_to_use = 1;
> >> +
> > You can freely move this to loongson_gmac_data() method. And then, in
> > the patch adding the GNET-support, you'll be able to provide these fields
> > initialization in the loongson_gnet_data() method together with the
> > plat->tx_queues_cfg[*].coe_unsupported flag init. Thus the probe()
> > method will get to be smaller and easier to read, and the
> > loongson_*_data() method will be more coherent.
>
> As you said, at first glance, putting them in loongson_gnet_data()
> method is fine,
>
> but in LS2K2000:
>
>          plat->rx_queues_to_use = CHANNEL_NUM;    // CHANNEL_NUM = 8;
>          plat->tx_queues_to_use = CHANNEL_NUM;
>
> So we need to distinguish between them. At the same time, we have to
> distinguish
>
> between LS2K2000 in probe() method. Why not put them inside probe, which
> will
>
> save a lot of duplicate code, like this:
>
>      struct stmmac_resources res;
>      struct loongson_data *ld;
>
> ...
>
>      memset(&res, 0, sizeof(res));
>      res.addr = pcim_iomap_table(pdev)[0];
>      ld->gmac_verion = readl(res.addr + GMAC_VERSION) & 0xff;
>
>      switch (ld->gmac_verion) {
>      case LOONGSON_DWMAC_CORE_1_00:
>          plat->rx_queues_to_use = CHANNEL_NUM;
>          plat->tx_queues_to_use = CHANNEL_NUM;
>
>          /* Only channel 0 supports checksum,
>           * so turn off checksum to enable multiple channels.
>           */
>          for (i = 1; i < CHANNEL_NUM; i++)
>              plat->tx_queues_cfg[i].coe_unsupported = 1;
>
>          ret = loongson_dwmac_config_msi(pdev, plat, &res, np);
>          break;
>      default:    /* 0x35 device and 0x37 device. */
>          plat->tx_queues_to_use = 1;
>          plat->rx_queues_to_use = 1;
>
>          ret = loongson_dwmac_config_legacy(pdev, plat, &res, np);
>          break;
>      }
>      if (ret)
>          goto err_disable_device;
>
>
> What do you think?
>
>
> Of course, if you insist, I'm willing to repeat this in the
>
> loongson_gnet_data() method.
In my opinion, it is the most elegant method by reading gmac_version
only once in the probe function, and save it in loongson_data for
other functions to use. So, it is good for me to put the switch-case
in the probe function.

Huacai
>
>
>
> Thanks,
>
> Yanteng
>

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