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Message-ID: <99ae096a-e14f-44bc-a520-a3198e7c0671@linux.dev>
Date: Tue, 22 Apr 2025 10:29:24 +0800
From: Yanteng Si <si.yanteng@...ux.dev>
To: Huacai Chen <chenhuacai@...nel.org>
Cc: Huacai Chen <chenhuacai@...ngson.cn>, Andrew Lunn
<andrew+netdev@...n.ch>, "David S . Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>, Feiyang Chen <chris.chenfeiyang@...il.com>,
loongarch@...ts.linux.dev, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, Andrew Lunn <andrew@...n.ch>,
Henry Chen <chenx97@...c.io>, Biao Dong <dongbiao@...ngson.cn>,
Baoqi Zhang <zhangbaoqi@...ngson.cn>
Subject: Re: [PATCH net-next V2 2/3] net: stmmac: dwmac-loongson: Add new
multi-chan IP core support
在 4/21/25 12:20 PM, Huacai Chen 写道:
> Hi, Yanteng,
>
> On Mon, Apr 21, 2025 at 10:04 AM Yanteng Si <si.yanteng@...ux.dev> wrote:
>>
>> 在 4/16/25 10:41 PM, Huacai Chen 写道:
>>> Add a new multi-chan IP core (0x12) support which is used in Loongson-
>>> 2K3000/Loongson-3B6000M. Compared with the 0x10 core, the new 0x12 core
>>> reduces channel numbers from 8 to 4, but checksum is supported for all
>>> channels.
>>>
>>> Reviewed-by: Andrew Lunn <andrew@...n.ch>
>>> Tested-by: Henry Chen <chenx97@...c.io>
>>> Tested-by: Biao Dong <dongbiao@...ngson.cn>
>>> Signed-off-by: Baoqi Zhang <zhangbaoqi@...ngson.cn>
>>> Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn>
>>> ---
>>> .../ethernet/stmicro/stmmac/dwmac-loongson.c | 62 +++++++++++--------
>>> 1 file changed, 37 insertions(+), 25 deletions(-)
>>>
>>> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c
>>> index 2fb7a137b312..57917f26ab4d 100644
>>> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c
>>> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c
>>> @@ -68,10 +68,11 @@
>>>
>>> #define PCI_DEVICE_ID_LOONGSON_GMAC 0x7a03
>>> #define PCI_DEVICE_ID_LOONGSON_GNET 0x7a13
>>> -#define DWMAC_CORE_LS_MULTICHAN 0x10 /* Loongson custom ID */
>>> -#define CHANNEL_NUM 8
>>> +#define DWMAC_CORE_MULTICHAN_V1 0x10 /* Loongson custom ID 0x10 */
>>> +#define DWMAC_CORE_MULTICHAN_V2 0x12 /* Loongson custom ID 0x12 */
>>>
>>> struct loongson_data {
>>> + u32 multichan;
>> In order to make the logic clearer, I suggest splitting this patch.:
>>
>>
>> 2/4 Add multichan for loongson_data
>>
>> 3/4 Add new multi-chan IP core support
> I don't think the patch is unclear now, the multichan flag is really a
> combination of DWMAC_CORE_MULTICHAN_V1 and DWMAC_CORE_MULTICHAN_V2.
OK, please describe this code modification in the commit message.
>
>>
>>> u32 loongson_id;
>>> struct device *dev;
>>> };
>>> @@ -119,18 +120,29 @@ static void loongson_default_data(struct pci_dev *pdev,
>>> plat->dma_cfg->pbl = 32;
>>> plat->dma_cfg->pblx8 = true;
>>>
>>> - if (ld->loongson_id == DWMAC_CORE_LS_MULTICHAN) {
>>> - plat->rx_queues_to_use = CHANNEL_NUM;
>>> - plat->tx_queues_to_use = CHANNEL_NUM;
>>> + switch (ld->loongson_id) {
>>> + case DWMAC_CORE_MULTICHAN_V1:
>> How about adding some comments? For example:
>>
>> case DWMAC_CORE_MULTICHAN_V1: /* 2K2000 */
>> case DWMAC_CORE_MULTICHAN_V2: /* 2K3000 and 3B6000M */
> Do you know why we deprecate PRID (a.k.a SOC name) detection and
> prefer CPUCFG detection in cpu_probe()? Because SOC-types and function
> features are orthogonal, they should not be strictly bound. There will
> be other SOCs using MULTICHAN_V1 or MULTICHAN_V2, should we update the
> comments every time when a new SOC publishes? There may also be one
> SOC with different IP-cores, then how to comment on this case?
In my opinion, having something is better than having nothing.
I've come up with a way to address your concerns:
case DWMAC_CORE_MULTICHAN_V1: /* 2K2000 ... */
case DWMAC_CORE_MULTICHAN_V2: /* 2K3000, 3B6000M ...*/
These limited comments are very friendly to developers outside
Loongson Company. Of course, I don't want to discuss this matter
any further. If you don't want to add code comments, I won't object
to this patch because of that.
>
>> ...
>>
>>> + ld->multichan = 1;
>>> + plat->rx_queues_to_use = 8;
>>> + plat->tx_queues_to_use = 8;
>>>
>>> /* Only channel 0 supports checksum,
>>> * so turn off checksum to enable multiple channels.
>>> */
>>> - for (int i = 1; i < CHANNEL_NUM; i++)
>>> + for (int i = 1; i < 8; i++)
>>> plat->tx_queues_cfg[i].coe_unsupported = 1;
>>> - } else {
>>> +
>>> + break;
>>> + case DWMAC_CORE_MULTICHAN_V2:
>>> + ld->multichan = 1;
>>> + plat->rx_queues_to_use = 4;
>>> + plat->tx_queues_to_use = 4;
>>> + break;
>>> + default:
>>> + ld->multichan = 0;
>>> plat->tx_queues_to_use = 1;
>>> plat->rx_queues_to_use = 1;
>>> + break;
>>> }
>>> }
>>>
>>> @@ -328,14 +340,14 @@ static struct mac_device_info *loongson_dwmac_setup(void *apriv)
>>> return NULL;
>>>
>>> /* The Loongson GMAC and GNET devices are based on the DW GMAC
>>> - * v3.50a and v3.73a IP-cores. But the HW designers have changed the
>>> - * GMAC_VERSION.SNPSVER field to the custom 0x10 value on the
>>> - * network controllers with the multi-channels feature
>>> + * v3.50a and v3.73a IP-cores. But the HW designers have changed
>>> + * the GMAC_VERSION.SNPSVER field to the custom 0x10/0x12 value
>>> + * on the network controllers with the multi-channels feature
>>> * available to emphasize the differences: multiple DMA-channels,
>>> * AV feature and GMAC_INT_STATUS CSR flags layout. Get back the
>>> * original value so the correct HW-interface would be selected.
>>> */
>>> - if (ld->loongson_id == DWMAC_CORE_LS_MULTICHAN) {
>>> + if (ld->multichan) {
>>> priv->synopsys_id = DWMAC_CORE_3_70;
>>> *dma = dwmac1000_dma_ops;
>>> dma->init_chan = loongson_dwmac_dma_init_channel;
>>> @@ -356,13 +368,13 @@ static struct mac_device_info *loongson_dwmac_setup(void *apriv)
>>> if (mac->multicast_filter_bins)
>>> mac->mcast_bits_log2 = ilog2(mac->multicast_filter_bins);
>>>
>>> - /* Loongson GMAC doesn't support the flow control. LS2K2000
>>> - * GNET doesn't support the half-duplex link mode.
>>> + /* Loongson GMAC doesn't support the flow control. Loongson GNET
>>> + * without multi-channel doesn't support the half-duplex link mode.
>>> */
>>> if (pdev->device == PCI_DEVICE_ID_LOONGSON_GMAC) {
>>> mac->link.caps = MAC_10 | MAC_100 | MAC_1000;
>>> } else {
>>> - if (ld->loongson_id == DWMAC_CORE_LS_MULTICHAN)
>>> + if (ld->multichan)
>>> mac->link.caps = MAC_ASYM_PAUSE | MAC_SYM_PAUSE |
>>> MAC_10 | MAC_100 | MAC_1000;
>>> else
>>> @@ -391,9 +403,11 @@ static int loongson_dwmac_msi_config(struct pci_dev *pdev,
>>> struct plat_stmmacenet_data *plat,
>>> struct stmmac_resources *res)
>>> {
>>> - int i, ret, vecs;
>>> + int i, ch_num, ret, vecs;
>>>
>>> - vecs = roundup_pow_of_two(CHANNEL_NUM * 2 + 1);
>>> + ch_num = min(plat->tx_queues_to_use, plat->rx_queues_to_use);
>> I'm curious. Will there still be hardware with RX not equal to TX in the
>> future?
> Currently rx queue number is equal to tx queue number, but
> min(plat->tx_queues_to_use, plat->rx_queues_to_use) is still the best
> solution. If not, which one should be used here? tx_queues_to_use or
> rx_queues_to_use?
All right.
Thanks,
Yanteng
>
> Huacai
>
>>
>> Thanks,
>>
>> Yanteng
>>
>>
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