Re: [RFC net-next 4/5] net: phy: Add support for IEEE standard test modes

[Florian Fainelli]

On 05/01/2018 10:29 AM, Woojung.Huh@xxxxxxxxxxxxx wrote:
> Hi Florian,
> 
>> diff --git a/drivers/net/phy/phy-tests.c b/drivers/net/phy/phy-tests.c
> ...
>> +/* genphy_set_test - Make a PHY enter one of the standard IEEE defined
>> + * test modes
>> + * @phydev: the PHY device instance
>> + * @test: the desired test mode
>> + * @data: test specific data (none)
>> + *
>> + * This function makes the designated @phydev enter the desired standard
>> + * 100BaseT2 or 1000BaseT test mode as defined in IEEE 802.3-2012 section TWO
>> + * and THREE under 32.6.1.2.1 and 40.6.1.1.2 respectively
>> + */
>> +int genphy_set_test(struct phy_device *phydev,
>> +		    struct ethtool_phy_test *test, const u8 *data)
>> +{
>> +	u16 shift, base, bmcr = 0;
>> +	int ret;
>> +
>> +	/* Exit test mode */
>> +	if (test->mode == PHY_STD_TEST_MODE_NORMAL) {
>> +		ret = phy_read(phydev, MII_CTRL1000);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		ret &= ~GENMASK(15, 13);
>> +
>> +		return phy_write(phydev, MII_CTRL1000, ret);
>> +	}
>> +
>> +	switch (test->mode) {
>> +	case PHY_STD_TEST_MODE_100BASET2_1:
>> +	case PHY_STD_TEST_MODE_100BASET2_2:
>> +	case PHY_STD_TEST_MODE_100BASET2_3:
>> +		if (!(phydev->supported & PHY_100BT_FEATURES))
>> +			return -EOPNOTSUPP;
>> +
>> +		shift = 14;
>> +		base = test->mode - PHY_STD_TEST_MODE_NORMAL;
>> +		bmcr = BMCR_SPEED100;
>> +		break;
>> +
>> +	case PHY_STD_TEST_MODE_1000BASET_1:
>> +	case PHY_STD_TEST_MODE_1000BASET_2:
>> +	case PHY_STD_TEST_MODE_1000BASET_3:
>> +	case PHY_STD_TEST_MODE_1000BASET_4:
>> +		if (!(phydev->supported & PHY_1000BT_FEATURES))
>> +			return -EOPNOTSUPP;
>> +
>> +		shift = 13;
>> +		base = test->mode - PHY_STD_TEST_MODE_100BASET2_MAX;
>> +		bmcr = BMCR_SPEED1000;
>> +		break;
>> +
>> +	default:
>> +		/* Let an upper driver deal with additional modes it may
>> +		 * support
>> +		 */
>> +		return -EOPNOTSUPP;
>> +	}
>> +
>> +	/* Force speed and duplex */
>> +	ret = phy_write(phydev, MII_BMCR, bmcr | BMCR_FULLDPLX);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	/* Set the desired test mode bit */
>> +	return phy_write(phydev, MII_CTRL1000, (test->mode + base) << shift);
>> +}
> For now, these are for 100B-T2 & 1000B-TX.
> But, other speeds such as 802.3bw/bq/cq have very similar format,
> how about make  phy_write() to BMCR & CTRL1000 as another function call per speed?

Not sure I completely understand your suggestion, do you mean that I
should break down the body of that function above such that there are
per-speed lower level functions? Something like the pseudo-code below:

genphy_set_test() {
	switch (mode) {
	case PHY_STD_TEST_MODE_100BASET2_1:
	..
	case PHY_STD_TEST_MODE_100BASET2_3:
		return genphy_set_100baset2();

	case PHY_STD_TEST_MODE_1000BASET_1:
	..
	case PHY_STD_TEST_MODE_1000BASET_4:
		return genphy_set_1000baset();

	case PHY_STD_TEST_MODE_8021BWQCQ_1:
		return genphy_set_100baset1();

}

Or did you want to see a different way of mapping a given speed/feature
set to a specific test function?
-- 
Florian