Subject: Re: [PATCH] net: stmmac: add dcrs parameter

From: Giuseppe CAVALLARO <[email-masked]>
Date: Mon, 25 Aug 2014 14:51:08 +0200

On 8/25/2014 2:34 PM, Chen-Yu Tsai wrote:
> Hi,
>
> On Mon, Aug 25, 2014 at 7:50 PM, Ley Foon Tan <[email-masked]> wrote:
>> This patch add the option to enable DCRS bit in GMAC control register.
>> Default is disabled if snps,dcrs is not defined.
>>
>> For MII, Carrier Sense (CRS) must be asserted during transmission
>> whereas in RGMII, CRS is not. RGMII does not provide a way to signal
>> loss of carrier during a transmission.
>>
>> When DCRS bit set high in control register, the MAC transmitter
>> ignore the (G)MII Carrier Sense signal during frame transmission
>> in the half-duplex mode. This request results in no errors generated
>> because of Loss of Carrier or No Carrier during such transmission.
>>
>> Signed-off-by: Ley Foon Tan <[email-masked]>
>> ---
>>   Documentation/devicetree/bindings/net/stmmac.txt      | 4 ++++
>>   drivers/net/ethernet/stmicro/stmmac/common.h          | 3 ++-
>>   drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c  | 4 +++-
>>   drivers/net/ethernet/stmicro/stmmac/stmmac_main.c     | 3 ++-
>>   drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 2 ++
>>   include/linux/stmmac.h                                | 1 +
>>   6 files changed, 14 insertions(+), 3 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/net/stmmac.txt b/Documentation/devicetree/bindings/net/stmmac.txt
>> index 9b03c57..a68e720 100644
>> --- a/Documentation/devicetree/bindings/net/stmmac.txt
>> +++ b/Documentation/devicetree/bindings/net/stmmac.txt
>> @@ -39,6 +39,10 @@ Optional properties:
>>     further clocks may be specified in derived bindings.
>>   - clock-names: One name for each entry in the clocks property, the
>>     first one should be "stmmaceth".
>> +- snps,dcrs: Enable DCRS bit in GMAC control register. This DCRS bit makes the
>> +       MAC transmitter ignore the (G)MII CRS signal during frame transmission
>> +       in the half-duplex mode. This request results in no errors generated
>
> Since you know this is only required under (G)MII, could you not re-use
> the "phy-mode" property, instead of adding another one?
>
> Better yet, use the "interface" field in the platform data. This way you'll
> fix non-DT devices as well. You could then avoid touching the platform driver,
> and just modify the driver core.

yes this is what I asked. Thx ChenYu for the this detail.
Ley Foon Tan, could you do that? Let me know

peppe

>
>
> Cheers
> ChenYu
>
>> +       because of Loss of Carrier or No Carrier during such transmission.
>>
>>   Examples:
>>
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
>> index de507c3..9abe221 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/common.h
>> +++ b/drivers/net/ethernet/stmicro/stmmac/common.h
>> @@ -445,10 +445,11 @@ struct mac_device_info {
>>          int multicast_filter_bins;
>>          int unicast_filter_entries;
>>          int mcast_bits_log2;
>> +       int dcrs;
>>   };
>>
>>   struct mac_device_info *dwmac1000_setup(void __iomem *ioaddr, int mcbins,
>> -                                       int perfect_uc_entries);
>> +                                       int perfect_uc_entries, int dcrs);
>>   struct mac_device_info *dwmac100_setup(void __iomem *ioaddr);
>>
>>   void stmmac_set_mac_addr(void __iomem *ioaddr, u8 addr[6],
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
>> index d8ef187..924d450 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
>> @@ -37,6 +37,7 @@ static void dwmac1000_core_init(struct mac_device_info *hw, int mtu)
>>          void __iomem *ioaddr = hw->pcsr;
>>          u32 value = readl(ioaddr + GMAC_CONTROL);
>>          value |= GMAC_CORE_INIT;
>> +       value |= hw->dcrs;
>>          if (mtu > 1500)
>>                  value |= GMAC_CONTROL_2K;
>>          if (mtu > 2000)
>> @@ -409,7 +410,7 @@ static const struct stmmac_ops dwmac1000_ops = {
>>   };
>>
>>   struct mac_device_info *dwmac1000_setup(void __iomem *ioaddr, int mcbins,
>> -                                       int perfect_uc_entries)
>> +                                       int perfect_uc_entries, int dcrs)
>>   {
>>          struct mac_device_info *mac;
>>          u32 hwid = readl(ioaddr + GMAC_VERSION);
>> @@ -422,6 +423,7 @@ struct mac_device_info *dwmac1000_setup(void __iomem *ioaddr, int mcbins,
>>          mac->multicast_filter_bins = mcbins;
>>          mac->unicast_filter_entries = perfect_uc_entries;
>>          mac->mcast_bits_log2 = 0;
>> +       mac->dcrs = dcrs;
>>
>>          if (mac->multicast_filter_bins)
>>                  mac->mcast_bits_log2 = ilog2(mac->multicast_filter_bins);
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> index 08addd6..bf35b19 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> @@ -2600,7 +2600,8 @@ static int stmmac_hw_init(struct stmmac_priv *priv)
>>                  priv->dev->priv_flags |= IFF_UNICAST_FLT;
>>                  mac = dwmac1000_setup(priv->ioaddr,
>>                                        priv->plat->multicast_filter_bins,
>> -                                     priv->plat->unicast_filter_entries);
>> +                                     priv->plat->unicast_filter_entries,
>> +                                     priv->plat->dcrs);
>>          } else {
>>                  mac = dwmac100_setup(priv->ioaddr);
>>          }
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
>> index bb524a9..07f895f 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
>> @@ -227,6 +227,8 @@ static int stmmac_probe_config_dt(struct platform_device *pdev,
>>                  pr_warn("force_sf_dma_mode is ignored if force_thresh_dma_mode is set.");
>>          }
>>
>> +       plat->dcrs = of_property_read_bool(np, "snps,dcrs");
>> +
>>          return 0;
>>   }
>>   #else
>> diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
>> index cd63851..6367f42 100644
>> --- a/include/linux/stmmac.h
>> +++ b/include/linux/stmmac.h
>> @@ -114,6 +114,7 @@ struct plat_stmmacenet_data {
>>          int maxmtu;
>>          int multicast_filter_bins;
>>          int unicast_filter_entries;
>> +       int dcrs;
>>          void (*fix_mac_speed)(void *priv, unsigned int speed);
>>          void (*bus_setup)(void __iomem *ioaddr);
>>          void *(*setup)(struct platform_device *pdev);
>> --
>> 1.8.2.1
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe netdev" in
>> the body of a message to [email-masked]
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>