RE: [net-next, v3, 05/10] ethtool: add a new command for getting PHC virtual clocks

["Y.b. Lu" <yangbo.lu@nxp.com>]

Hi Jakub,

> -----Original Message-----
> From: Jakub Kicinski <kuba@kernel.org>
> Sent: 2021年6月16日 3:49
> To: Y.b. Lu <yangbo.lu@nxp.com>
> Cc: netdev@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-kselftest@vger.kernel.org; mptcp@lists.linux.dev; Richard Cochran
> <richardcochran@gmail.com>; David S . Miller <davem@davemloft.net>; Mat
> Martineau <mathew.j.martineau@linux.intel.com>; Matthieu Baerts
> <matthieu.baerts@tessares.net>; Shuah Khan <shuah@kernel.org>; Michal
> Kubecek <mkubecek@suse.cz>; Florian Fainelli <f.fainelli@gmail.com>;
> Andrew Lunn <andrew@lunn.ch>; Rui Sousa <rui.sousa@nxp.com>; Sebastien
> Laveze <sebastien.laveze@nxp.com>
> Subject: Re: [net-next, v3, 05/10] ethtool: add a new command for getting PHC
> virtual clocks
> 
> On Tue, 15 Jun 2021 17:45:12 +0800 Yangbo Lu wrote:
> > Add an interface for getting PHC (PTP Hardware Clock) virtual clocks,
> > which are based on PHC physical clock providing hardware timestamp to
> > network packets.
> >
> > Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
> 
> > diff --git a/include/uapi/linux/ethtool.h
> > b/include/uapi/linux/ethtool.h index cfef6b08169a..0fb04f945767 100644
> > --- a/include/uapi/linux/ethtool.h
> > +++ b/include/uapi/linux/ethtool.h
> > @@ -17,6 +17,7 @@
> >  #include <linux/const.h>
> >  #include <linux/types.h>
> >  #include <linux/if_ether.h>
> > +#include <linux/ptp_clock.h>
> >
> >  #ifndef __KERNEL__
> >  #include <limits.h> /* for INT_MAX */ @@ -1341,6 +1342,18 @@ struct
> > ethtool_ts_info {
> >  	__u32	rx_reserved[3];
> >  };
> >
> > +/**
> > + * struct ethtool_phc_vclocks - holds a device's PTP virtual clocks
> > + * @cmd: command number = %ETHTOOL_GET_PHC_VCLOCKS
> > + * @num: number of PTP vclocks
> > + * @index: all index values of PTP vclocks  */ struct
> > +ethtool_phc_vclocks {
> > +	__u32	cmd;
> > +	__u8	num;
> > +	__s32	index[PTP_MAX_VCLOCKS];
> > +};
> > +
> >  /*
> >   * %ETHTOOL_SFEATURES changes features present in features[].valid to
> the
> >   * values of corresponding bits in features[].requested. Bits in
> > .requested @@ -1552,6 +1565,7 @@ enum ethtool_fec_config_bits {
> >  #define ETHTOOL_PHY_STUNABLE	0x0000004f /* Set PHY tunable
> configuration */
> >  #define ETHTOOL_GFECPARAM	0x00000050 /* Get FEC settings */
> >  #define ETHTOOL_SFECPARAM	0x00000051 /* Set FEC settings */
> > +#define ETHTOOL_GET_PHC_VCLOCKS	0x00000052 /* Get PHC virtual
> clocks info */
> 
> We don't add new IOCTL commands, only netlink API is going to be extended.
> Please remove the IOCTL interface & uAPI.

Will remove. Thanks.

> 
> >  /* compatibility with older code */
> >  #define SPARC_ETH_GSET		ETHTOOL_GSET
> 
> > +/* PHC VCLOCKS */
> > +
> > +enum {
> > +	ETHTOOL_A_PHC_VCLOCKS_UNSPEC,
> > +	ETHTOOL_A_PHC_VCLOCKS_HEADER,			/* nest - _A_HEADER_*
> */
> > +	ETHTOOL_A_PHC_VCLOCKS_NUM,			/* u8 */
> 
> u32, no need to limit yourself, the netlink attribute is rounded up to 4B
> anyway.

Get it. Will use u32.

> 
> > +	ETHTOOL_A_PHC_VCLOCKS_INDEX,			/* s32 */
> 
> This is an array, AFAICT, not a single s32.

Will fix. Thanks.

> 
> > +
> > +	/* add new constants above here */
> > +	__ETHTOOL_A_PHC_VCLOCKS_CNT,
> > +	ETHTOOL_A_PHC_VCLOCKS_MAX = (__ETHTOOL_A_PHC_VCLOCKS_CNT -
> 1) };
> > +
> >  /* CABLE TEST */
> >
> >  enum {
> 
> > +static int phc_vclocks_fill_reply(struct sk_buff *skb,
> > +				  const struct ethnl_req_info *req_base,
> > +				  const struct ethnl_reply_data *reply_base) {
> > +	const struct phc_vclocks_reply_data *data =
> > +		PHC_VCLOCKS_REPDATA(reply_base);
> > +	const struct ethtool_phc_vclocks *phc_vclocks = &data->phc_vclocks;
> > +
> > +	if (phc_vclocks->num <= 0)
> > +		return 0;
> > +
> > +	if (nla_put_u32(skb, ETHTOOL_A_PHC_VCLOCKS_NUM, phc_vclocks->num)
> ||
> > +	    nla_put(skb, ETHTOOL_A_PHC_VCLOCKS_INDEX,
> > +		    sizeof(phc_vclocks->index), phc_vclocks->index))
> 
> Looks like you'll report the whole array, why not just num?

Will report just num. Thanks.

> 
> > +		return -EMSGSIZE;
> > +
> > +	return 0;
> > +}
> > +
> > +const struct ethnl_request_ops ethnl_phc_vclocks_request_ops = {
> > +	.request_cmd		= ETHTOOL_MSG_PHC_VCLOCKS_GET,
> > +	.reply_cmd		= ETHTOOL_MSG_PHC_VCLOCKS_GET_REPLY,
> > +	.hdr_attr		= ETHTOOL_A_PHC_VCLOCKS_HEADER,
> > +	.req_info_size		= sizeof(struct phc_vclocks_req_info),
> > +	.reply_data_size	= sizeof(struct phc_vclocks_reply_data),
> > +
> > +	.prepare_data		= phc_vclocks_prepare_data,
> > +	.reply_size		= phc_vclocks_reply_size,
> > +	.fill_reply		= phc_vclocks_fill_reply,
> > +};