Re: [PATCH v5 1/2] ethtool: provide UAPI for PHY master/slave configuration.
From: Michal Kubecek <hidden>
Date: 2020-05-04 09:10:49
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On Mon, May 04, 2020 at 09:12:13AM +0200, Oleksij Rempel wrote:
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This UAPI is needed for BroadR-Reach 100BASE-T1 devices. Due to lack of auto-negotiation support, we needed to be able to configure the MASTER-SLAVE role of the port manually or from an application in user space. The same UAPI can be used for 1000BASE-T or MultiGBASE-T devices to force MASTER or SLAVE role. See IEEE 802.3-2018: 22.2.4.3.7 MASTER-SLAVE control register (Register 9) 22.2.4.3.8 MASTER-SLAVE status register (Register 10) 40.5.2 MASTER-SLAVE configuration resolution 45.2.1.185.1 MASTER-SLAVE config value (1.2100.14) 45.2.7.10 MultiGBASE-T AN control 1 register (Register 7.32) The MASTER-SLAVE role affects the clock configuration: ------------------------------------------------------------------------------- When the PHY is configured as MASTER, the PMA Transmit function shall source TX_TCLK from a local clock source. When configured as SLAVE, the PMA Transmit function shall source TX_TCLK from the clock recovered from data stream provided by MASTER. iMX6Q KSZ9031 XXX ------\ /-----------\ /------------\ | | | | | MAC |<----RGMII----->| PHY Slave |<------>| PHY Master | |<--- 125 MHz ---+-<------/ | | \ | ------/ \-----------/ \------------/ ^ \-TX_TCLK ------------------------------------------------------------------------------- Since some clock or link related issues are only reproducible in a specific MASTER-SLAVE-role, MAC and PHY configuration, it is beneficial to provide generic (not 100BASE-T1 specific) interface to the user space for configuration flexibility and trouble shooting. Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> ---diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index ac2784192472f..42dda9d2082ee 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c@@ -1768,6 +1768,90 @@ int genphy_setup_forced(struct phy_device *phydev) } EXPORT_SYMBOL(genphy_setup_forced); +static int genphy_setup_master_slave(struct phy_device *phydev) +{ + u16 ctl = 0; + + if (!phydev->is_gigabit_capable) + return 0;
Why did you revert to silently ignoring requests in this case? On the other hand, we might rather want to do a more generic check which would handle all drivers not supporting the feature, see below. [...]
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@@ -287,14 +308,37 @@ static bool ethnl_auto_linkmodes(struct ethtool_link_ksettings *ksettings, __ETHTOOL_LINK_MODE_MASK_NBITS); } +static int ethnl_validate_master_slave_cfg(u8 cfg) +{ + switch (cfg) { + case MASTER_SLAVE_CFG_MASTER_PREFERRED: + case MASTER_SLAVE_CFG_SLAVE_PREFERRED: + case MASTER_SLAVE_CFG_MASTER_FORCE: + case MASTER_SLAVE_CFG_SLAVE_FORCE: + return 1; + } + + return 0; +}
Nitpick: bool would be more appropriate as return value.
+
static int ethnl_update_linkmodes(struct genl_info *info, struct nlattr **tb,
struct ethtool_link_ksettings *ksettings,
bool *mod)
{
struct ethtool_link_settings *lsettings = &ksettings->base;
bool req_speed, req_duplex;
+ const struct nlattr *master_slave_cfg;
int ret;
+ master_slave_cfg = tb[ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG];
+ if (master_slave_cfg) {
+ u8 cfg = nla_get_u8(master_slave_cfg);
+ if (!ethnl_validate_master_slave_cfg(cfg)) {
+ GENL_SET_ERR_MSG(info, "LINKMODES_MASTER_SLAVE_CFG contains not valid value");
+ return -EOPNOTSUPP;
+ }
+ }
Please set also the "bad attribute" in extack, it may help
non-interactive clients.
Also, it would be nice to report error if client wants to set master/slave but
driver does not support it. How about this?
if (master_slave_cfg) {
u8 cfg = nla_get_u8(master_slave_cfg);
if (lsettings->master_slave_cfg == MASTER_SLAVE_CFG_UNSUPPORTED) {
NL_SET_ERR_MSG_ATTR(info->extack, master_slave_cfg,
"master/slave configuration not supported by device");
return -EOPNOTSUPP;
}
if (!ethnl_validate_master_slave_cfg(cfg)) {
NL_SET_ERR_MSG_ATTR(info->extack, master_slave_cfg,
"master/slave value is invalid");
return -EOPNOTSUPP;
}
}
Do you plan to allow handling master/slave also via ioctl()? If yes, we should
also add the sanity checks to ioctl code path. If not, we should prevent
passing non-zero values from userspace to driver.
Other than this, the patch looks good to me.
Michal
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*mod = false; req_speed = tb[ETHTOOL_A_LINKMODES_SPEED]; req_duplex = tb[ETHTOOL_A_LINKMODES_DUPLEX];@@ -311,6 +355,7 @@ static int ethnl_update_linkmodes(struct genl_info *info, struct nlattr **tb, mod); ethnl_update_u8(&lsettings->duplex, tb[ETHTOOL_A_LINKMODES_DUPLEX], mod); + ethnl_update_u8(&lsettings->master_slave_cfg, master_slave_cfg, mod); if (!tb[ETHTOOL_A_LINKMODES_OURS] && lsettings->autoneg && (req_speed || req_duplex) &&-- 2.26.2