Re: [PATCH ethtool v2] ethtool: Support for FEC encoding control

["John W. Linville" <linville@tuxdriver.com>]

Applied, thanks!

On Mon, Dec 18, 2017 at 02:57:41PM -0800, Jakub Kicinski wrote:
> From: Dustin Byford <dustin@cumulusnetworks.com>
> 
> As FEC settings and different FEC modes are mandatory
> and configurable across various interfaces of 25G/50G/100G/40G,
> the lack of FEC encoding control and reporting today is a source
> for interoperability issues for many vendors
> 
> set-fec/show-fec option(s) are designed to provide control and report
> the FEC encoding on the link.
> 
> $ethtool --set-fec swp1 encoding [off | RS | BaseR | auto]
> 
> Encoding: Types of encoding
> Off    :  Turning off FEC
> RS     :  Force RS-FEC encoding
> BaseR  :  Force BaseR encoding
> Auto   :  Default FEC settings for drivers, and would represent
>           asking the hardware to essentially go into a best effort mode.
> 
> Here are a few examples of what we would expect if encoding=auto:
> - if autoneg is on, we are  expecting FEC to be negotiated as on or off
>   as long as protocol supports it
> - if the hardware is capable of detecting the FEC encoding on it's
>   receiver it will reconfigure its encoder to match
> - in absence of the above, the configuration would be set to IEEE
>   defaults.
> 
> From our understanding, this is essentially what most hardware/driver
> combinations are doing today in the absence of a way for users to
> control the behavior.
> 
> $ethtool --show-fec  swp1
> FEC parameters for swp1:
> FEC encodings:  RS
> 
> ethtool devname output:
> $ethtool swp1
> Settings for swp1:
> root@hpe-7712-03:~# ethtool swp18
> Settings for swp18:
>     Supported ports: [ FIBRE ]
>     Supported link modes:   40000baseCR4/Full
>                             40000baseSR4/Full
>                             40000baseLR4/Full
>                             100000baseSR4/Full
>                             100000baseCR4/Full
>                             100000baseLR4_ER4/Full
>     Supported pause frame use: No
>     Supports auto-negotiation: Yes
>     Supported FEC modes: [RS | BaseR | None | Not reported]
>     Advertised link modes:  Not reported
>     Advertised pause frame use: No
>     Advertised auto-negotiation: No
>     Advertised FEC modes: [RS | BaseR | None | Not reported]
>     Speed: 100000Mb/s
>     Duplex: Full
>     Port: FIBRE
>     PHYAD: 106
>     Transceiver: internal
>     Auto-negotiation: off
>     Link detected: yes
> 
> Signed-off-by: Vidya Sagar Ravipati <vidya.chowdary@gmail.com>
> Signed-off-by: Dustin Byford <dustin@cumulusnetworks.com>
> [code style + man page edits + commit message update]
> Signed-off-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
> ---
> v2:
>  - don't break lines after opening parnes.
> 
>  ethtool.8.in |  31 ++++++++++++++++
>  ethtool.c    | 119 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 150 insertions(+)
> 
> diff --git a/ethtool.8.in b/ethtool.8.in
> index 7ca8bfe43607..9573ffdc985d 100644
> --- a/ethtool.8.in
> +++ b/ethtool.8.in
> @@ -378,6 +378,13 @@ ethtool \- query or control network driver and hardware settings
>  .RB [ ap-shared ]
>  .RB [ dedicated ]
>  .RB [ all ]
> +.HP
> +.B ethtool \-\-show\-fec
> +.I devname
> +.HP
> +.B ethtool \-\-set\-fec
> +.I devname
> +.B4 encoding auto off rs baser
>  .
>  .\" Adjust lines (i.e. full justification) and hyphenate.
>  .ad
> @@ -1070,6 +1077,30 @@ All components dedicated to this interface
>  .B all
>  All components used by this interface, even if shared
>  .RE
> +.TP
> +.B \-\-show\-fec
> +Queries the specified network device for its support of Forward Error Correction.
> +.TP
> +.B \-\-set\-fec
> +Configures Forward Error Correction for the specified network device.
> +
> +Forward Error Correction modes selected by a user are expected to be persisted
> +after any hotplug events. If a module is swapped that does not support the
> +current FEC mode, the driver or firmware must take the link down
> +administratively and report the problem in the system logs for users to correct.
> +.RS 4
> +.TP
> +.A4 encoding auto off rs baser
> +Sets the FEC encoding for the device.
> +.TS
> +nokeep;
> +lB	l.
> +auto	Use the driver's default encoding
> +off	Turn off FEC
> +RS	Force RS-FEC encoding
> +BaseR	Force BaseR encoding
> +.TE
> +.RE
>  .SH BUGS
>  Not supported (in part or whole) on all network drivers.
>  .SH AUTHOR
> diff --git a/ethtool.c b/ethtool.c
> index 488f6bfb8378..79c076e42c6e 100644
> --- a/ethtool.c
> +++ b/ethtool.c
> @@ -542,6 +542,9 @@ static void init_global_link_mode_masks(void)
>  		ETHTOOL_LINK_MODE_Pause_BIT,
>  		ETHTOOL_LINK_MODE_Asym_Pause_BIT,
>  		ETHTOOL_LINK_MODE_Backplane_BIT,
> +		ETHTOOL_LINK_MODE_FEC_NONE_BIT,
> +		ETHTOOL_LINK_MODE_FEC_RS_BIT,
> +		ETHTOOL_LINK_MODE_FEC_BASER_BIT,
>  	};
>  	unsigned int i;
>  
> @@ -689,6 +692,7 @@ static void dump_link_caps(const char *prefix, const char *an_prefix,
>  	};
>  	int indent;
>  	int did1, new_line_pend, i;
> +	int fecreported = 0;
>  
>  	/* Indent just like the separate functions used to */
>  	indent = strlen(prefix) + 14;
> @@ -740,6 +744,26 @@ static void dump_link_caps(const char *prefix, const char *an_prefix,
>  			fprintf(stdout, "Yes\n");
>  		else
>  			fprintf(stdout, "No\n");
> +
> +		fprintf(stdout, "	%s FEC modes:", prefix);
> +		if (ethtool_link_mode_test_bit(ETHTOOL_LINK_MODE_FEC_NONE_BIT,
> +					       mask)) {
> +			fprintf(stdout, " None");
> +			fecreported = 1;
> +		}
> +		if (ethtool_link_mode_test_bit(ETHTOOL_LINK_MODE_FEC_BASER_BIT,
> +					       mask)) {
> +			fprintf(stdout, " BaseR");
> +			fecreported = 1;
> +		}
> +		if (ethtool_link_mode_test_bit(ETHTOOL_LINK_MODE_FEC_RS_BIT,
> +					       mask)) {
> +			fprintf(stdout, " RS");
> +			fecreported = 1;
> +		}
> +		if (!fecreported)
> +			fprintf(stdout, " Not reported");
> +		fprintf(stdout, "\n");
>  	}
>  }
>  
> @@ -1562,6 +1586,20 @@ static void dump_eeecmd(struct ethtool_eee *ep)
>  	dump_link_caps("Link partner advertised EEE", "", link_mode, 1);
>  }
>  
> +static void dump_fec(u32 fec)
> +{
> +	if (fec & ETHTOOL_FEC_NONE)
> +		fprintf(stdout, " None");
> +	if (fec & ETHTOOL_FEC_AUTO)
> +		fprintf(stdout, " Auto");
> +	if (fec & ETHTOOL_FEC_OFF)
> +		fprintf(stdout, " Off");
> +	if (fec & ETHTOOL_FEC_BASER)
> +		fprintf(stdout, " BaseR");
> +	if (fec & ETHTOOL_FEC_RS)
> +		fprintf(stdout, " RS");
> +}
> +
>  #define N_SOTS 7
>  
>  static char *so_timestamping_labels[N_SOTS] = {
> @@ -4812,6 +4850,84 @@ static int do_set_phy_tunable(struct cmd_context *ctx)
>  	return err;
>  }
>  
> +static int fecmode_str_to_type(const char *str)
> +{
> +	int fecmode = 0;
> +
> +	if (!str)
> +		return fecmode;
> +
> +	if (!strcasecmp(str, "auto"))
> +		fecmode |= ETHTOOL_FEC_AUTO;
> +	else if (!strcasecmp(str, "off"))
> +		fecmode |= ETHTOOL_FEC_OFF;
> +	else if (!strcasecmp(str, "rs"))
> +		fecmode |= ETHTOOL_FEC_RS;
> +	else if (!strcasecmp(str, "baser"))
> +		fecmode |= ETHTOOL_FEC_BASER;
> +
> +	return fecmode;
> +}
> +
> +static int do_gfec(struct cmd_context *ctx)
> +{
> +	struct ethtool_fecparam feccmd = { 0 };
> +	int rv;
> +
> +	if (ctx->argc != 0)
> +		exit_bad_args();
> +
> +	feccmd.cmd = ETHTOOL_GFECPARAM;
> +	rv = send_ioctl(ctx, &feccmd);
> +	if (rv != 0) {
> +		perror("Cannot get FEC settings");
> +		return rv;
> +	}
> +
> +	fprintf(stdout, "FEC parameters for %s:\n", ctx->devname);
> +	fprintf(stdout, "Configured FEC encodings:");
> +	dump_fec(feccmd.fec);
> +	fprintf(stdout, "\n");
> +
> +	fprintf(stdout, "Active FEC encoding:");
> +	dump_fec(feccmd.active_fec);
> +	fprintf(stdout, "\n");
> +
> +	return 0;
> +}
> +
> +static int do_sfec(struct cmd_context *ctx)
> +{
> +	char *fecmode_str = NULL;
> +	struct ethtool_fecparam feccmd;
> +	struct cmdline_info cmdline_fec[] = {
> +		{ "encoding", CMDL_STR,  &fecmode_str,  &feccmd.fec},
> +	};
> +	int changed;
> +	int fecmode;
> +	int rv;
> +
> +	parse_generic_cmdline(ctx, &changed, cmdline_fec,
> +			      ARRAY_SIZE(cmdline_fec));
> +
> +	if (!fecmode_str)
> +		exit_bad_args();
> +
> +	fecmode = fecmode_str_to_type(fecmode_str);
> +	if (!fecmode)
> +		exit_bad_args();
> +
> +	feccmd.cmd = ETHTOOL_SFECPARAM;
> +	feccmd.fec = fecmode;
> +	rv = send_ioctl(ctx, &feccmd);
> +	if (rv != 0) {
> +		perror("Cannot set FEC settings");
> +		return rv;
> +	}
> +
> +	return 0;
> +}
> +
>  #ifndef TEST_ETHTOOL
>  int send_ioctl(struct cmd_context *ctx, void *cmd)
>  {
> @@ -5000,6 +5116,9 @@ static const struct option {
>  	  "		[ ap-shared ]\n"
>  	  "		[ dedicated ]\n"
>  	  "		[ all ]\n"},
> +	{ "--show-fec", 1, do_gfec, "Show FEC settings"},
> +	{ "--set-fec", 1, do_sfec, "Set FEC settings",
> +	  "		[ encoding auto|off|rs|baser ]\n"},
>  	{ "-h|--help", 0, show_usage, "Show this help" },
>  	{ "--version", 0, do_version, "Show version number" },
>  	{}
> -- 
> 2.15.1
> 
> 

-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.