netdev - Re: [PATCH net-next v10 4/7] net: tn40xx: add basic Tx handling

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Date: Fri, 14 Jun 2024 11:41:52 +0900 (JST)
From: FUJITA Tomonori <fujita.tomonori@...il.com>
To: kuba@...nel.org
Cc: fujita.tomonori@...il.com, netdev@...r.kernel.org, andrew@...n.ch,
 horms@...nel.org, jiri@...nulli.us, pabeni@...hat.com,
 linux@...linux.org.uk, hfdevel@....net, naveenm@...vell.com,
 jdamato@...tly.com
Subject: Re: [PATCH net-next v10 4/7] net: tn40xx: add basic Tx handling

On Thu, 13 Jun 2024 17:48:08 -0700
Jakub Kicinski <kuba@...nel.org> wrote:

> On Tue, 11 Jun 2024 13:52:14 +0900 FUJITA Tomonori wrote:
>> +	/* 1. load MAC (obsolete) */
>> +	/* 2. disable Rx (and Tx) */
>> +	tn40_write_reg(priv, TN40_REG_GMAC_RXF_A, 0);
>> +	mdelay(100);
> 
> Why mdelay()? 100ms of CPU spinning in a loop is not great.
> I only see calls to tn40_sw_reset() from open and close, both
> of which can sleep so you should be able to use msleep().

Yes, msleep() works here. Will fix.

>> +	/* 3. Disable port */
>> +	tn40_write_reg(priv, TN40_REG_DIS_PORT, 1);
>> +	/* 4. Disable queue */
>> +	tn40_write_reg(priv, TN40_REG_DIS_QU, 1);
>> +	/* 5. Wait until hw is disabled */
>> +	for (i = 0; i < 50; i++) {
>> +		if (tn40_read_reg(priv, TN40_REG_RST_PORT) & 1)
>> +			break;
>> +		mdelay(10);
> 
> read_poll_timeout() ?

Will fix.

>> +	}
>> +	if (i == 50)
>> +		netdev_err(priv->ndev, "SW reset timeout. continuing anyway\n");
> 
> 
>> +	if (unlikely(vid >= 4096)) {
> 
> can the core actually call with an invalid vid? I don't thinks so..

Will remove.

>> +	struct tn40_priv *priv = netdev_priv(ndev);
>> +
>> +	u32 rxf_val = TN40_GMAC_RX_FILTER_AM | TN40_GMAC_RX_FILTER_AB |
>> +		TN40_GMAC_RX_FILTER_OSEN | TN40_GMAC_RX_FILTER_TXFC;
>> +	int i;
>> +
> 
> nit: no empty lines between variable declarations

Oops, will fix.

>> +		u8 hash;
>> +		struct netdev_hw_addr *mclist;
>> +		u32 reg, val;
> 
> nit: declaration lines longest to shortest within a block

Sorry, I thought that xmastree tool can find this but it can't. Will fix.

>> +static void tn40_get_stats(struct net_device *ndev,
>> +			   struct rtnl_link_stats64 *stats)
>> +{
>> +	struct tn40_priv *priv = netdev_priv(ndev);
>> +
>> +	netdev_stats_to_stats64(stats, &priv->net_stats);
> 
> You should hold the stats in driver priv, probably:
> 
> from struct net_device:
> 
> 	struct net_device_stats	stats; /* not used by modern drivers */
>

Currently, net_device_stats struct is in tn40_priv struct. You meant
the driver shouldn't use net_device_stats struct?

Note that some TX40xx chips support HW statistics. Seems that my NIC
supports the feature so I plan to send a patch for that after the
initial driver is merged.

>> +static int tn40_priv_init(struct tn40_priv *priv)
>> +{
>> +	int ret;
>> +
>> +	tn40_set_link_speed(priv, 0);
>> +
>> +	ret = tn40_hw_reset(priv);
>> +	if (ret)
>> +		return ret;
> 
> But probe already called reset, is there a reason to reset multiple
> times? Would be good to add some reason why in a comment (if you know)

I didn't know why the original driver does this. Seems the NIC works
without the above hw reset. Will remove.

>> +	/* Set GPIO[9:0] to output 0 */
>> +	tn40_write_reg(priv, 0x51E0, 0x30010006);	/* GPIO_OE_ WR CMD */
>> +	tn40_write_reg(priv, 0x51F0, 0x0);	/* GPIO_OE_ DATA */
>> +	tn40_write_reg(priv, TN40_REG_MDIO_CMD_STAT, 0x3ec8);
>> +
>> +	// we use tx descriptors to load a firmware.
> 
> nit: stick to a single style of comments? ;)

Oops, will fix.


Thanks a lot!