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Message-ID: <f2ade097-5f4c-4de6-a7f2-9f3d026f95e7@loongson.cn>
Date: Mon, 13 May 2024 17:49:10 +0800
From: Yanteng Si <siyanteng@...ngson.cn>
To: Serge Semin <fancer.lancer@...il.com>
Cc: andrew@...n.ch, hkallweit1@...il.com, peppe.cavallaro@...com,
alexandre.torgue@...s.st.com, joabreu@...opsys.com, Jose.Abreu@...opsys.com,
chenhuacai@...nel.org, linux@...linux.org.uk, guyinggang@...ngson.cn,
netdev@...r.kernel.org, chris.chenfeiyang@...il.com, siyanteng01@...il.com
Subject: Re: [PATCH net-next v12 02/15] net: stmmac: Add multi-channel support
在 2024/5/13 17:45, Serge Semin 写道:
> On Fri, May 10, 2024 at 06:13:40PM +0800, Yanteng Si wrote:
>> Hi Serge
>>
>> 在 2024/5/3 06:02, Serge Semin 写道:
>>> On Thu, Apr 25, 2024 at 09:01:55PM +0800, Yanteng Si wrote:
>>>> DW GMAC v3.x multi-channels feature is implemented as multiple
>>>> sets of the same CSRs. Here is only preliminary support, it will
>>>> be useful for the driver further evolution and for the users
>>>> having multi-channel DWGMAC v3.x devices.
>>> Why do you call it "preliminary"? AFAICS it's a fully functional
>>> support with no restrictions. Am I wrong?
>>>
>>> I would reformulate the commit message as:
>>>
>>> "DW GMAC v3.73 can be equipped with the Audio Video (AV) feature which
>>> enables transmission of time-sensitive traffic over bridged local area
>>> networks (DWC Ethernet QoS Product). In that case there can be up to two
>>> additional DMA-channels available with no Tx COE support (unless there is
>>> vendor-specific IP-core alterations). Each channel is implemented as a
>>> separate Control and Status register (CSR) for managing the transmit and
>>> receive functions, descriptor handling, and interrupt handling.
>>>
>>> Add the multi-channels DW GMAC controllers support just by making sure the
>>> already implemented DMA-configs are performed on the per-channel basis.
>>>
>>> Note the only currently known instance of the multi-channel DW GMAC
>>> IP-core is the LS2K2000 GNET controller, which has been released with the
>>> vendor-specific feature extension of having eight DMA-channels. The device
>>> support will be added in one of the following up commits."
>> OK.
>>>> @@ -153,7 +155,7 @@ static void dwmac1000_dma_operation_mode_rx(struct stmmac_priv *priv,
>>>> void __iomem *ioaddr, int mode,
>>>> u32 channel, int fifosz, u8 qmode)
>>>> {
>>>> - u32 csr6 = readl(ioaddr + DMA_CONTROL);
>>>> + u32 csr6 = readl(ioaddr + DMA_CHAN_CONTROL(channel));
>>>> if (mode == SF_DMA_MODE) {
>>>> pr_debug("GMAC: enable RX store and forward mode\n");
>>>> @@ -175,14 +177,14 @@ static void dwmac1000_dma_operation_mode_rx(struct stmmac_priv *priv,
>>>> /* Configure flow control based on rx fifo size */
>>>> csr6 = dwmac1000_configure_fc(csr6, fifosz);
>>>> - writel(csr6, ioaddr + DMA_CONTROL);
>>>> + writel(csr6, ioaddr + DMA_CHAN_CONTROL(channel));
>>>> }
>>>> static void dwmac1000_dma_operation_mode_tx(struct stmmac_priv *priv,
>>>> void __iomem *ioaddr, int mode,
>>>> u32 channel, int fifosz, u8 qmode)
>>>> {
>>>> - u32 csr6 = readl(ioaddr + DMA_CONTROL);
>>>> + u32 csr6 = readl(ioaddr + DMA_CHAN_CONTROL(channel));
>>>> if (mode == SF_DMA_MODE) {
>>>> pr_debug("GMAC: enable TX store and forward mode\n");
>>>> @@ -209,7 +211,7 @@ static void dwmac1000_dma_operation_mode_tx(struct stmmac_priv *priv,
>>>> csr6 |= DMA_CONTROL_TTC_256;
>>>> }
>>>> - writel(csr6, ioaddr + DMA_CONTROL);
>>>> + writel(csr6, ioaddr + DMA_CHAN_CONTROL(channel));
>>>> }
>>> Just figured out that besides of the channel-related changes you also need
>>> to have the stmmac_dma_operation_mode() method fixed. So one wouldn't
>>> redistribute the detected Tx/Rx FIFO between the channels. Each DW GMAC
>>> channel has separate FIFO of the same size. The databook explicitly says
>>> about that:
>>>
>>> "The Tx FIFO size of all selected Transmit channels is always same.
>>> Similarly, the Rx FIFO size of all selected Receive channels is same.
>>> These channels cannot be of different sizes."
>>>
>> Should I do this, right?
>>
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> index 33d04243b4d8..9d4148daee68 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> @@ -2371,8 +2371,13 @@ static void stmmac_dma_operation_mode(struct
>> stmmac_priv *priv)
>> txfifosz = priv->dma_cap.tx_fifo_size;
>>
>> /* Adjust for real per queue fifo size */
>> - rxfifosz /= rx_channels_count;
>> - txfifosz /= tx_channels_count;
>> + if ((priv->synopsys_id != DWMAC_CORE_3_40) ||
>> + (priv->synopsys_id != DWMAC_CORE_3_50) ||
>> + (priv->synopsys_id != DWMAC_CORE_3_70)) {
>> + rxfifosz /= rx_channels_count;
>> + txfifosz /= tx_channels_count;
>> + }
>> +
>>
>> if (priv->plat->force_thresh_dma_mode) {
>> txmode = tc;
> Seeing the shared FIFO memory is specific for the DW QoS Eth and DW
> xGMAC IP-cores let's use the has_gmac4 and has_xgmac flags instead:
>
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -2371,8 +2371,13 @@ static void stmmac_dma_operation_mode(struct stmmac_priv *priv)
> if (txfifosz == 0)
> txfifosz = priv->dma_cap.tx_fifo_size;
>
> - /* Adjust for real per queue fifo size */
> - rxfifosz /= rx_channels_count;
> - txfifosz /= tx_channels_count;
> + /* Split up the shared Tx/Rx FIFO memory on DW QoS Eth and DW XGMAC */
> + if (priv->plat->has_gmac4 || priv->plat->has_xgmac) {
> + rxfifosz /= rx_channels_count;
> + txfifosz /= tx_channels_count;
> + }
>
> if (priv->plat->force_thresh_dma_mode) {
> txmode = tc;
OK.
Thanks,
Yanteng
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