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net: phy: micrel: ksz9031/ksz9131: add cabletest support
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Add cable test support for Micrel KSZ9x31 PHYs.

Tested on i.MX8M Mini with KSZ9131RNX in 100/Full mode with pairs shuffled
before magnetics:
(note: Cable test started/completed messages are omitted)

  mx8mm-ksz9131-a-d-connected$ ethtool --cable-test eth0
  Pair A code OK
  Pair B code Short within Pair
  Pair B, fault length: 0.80m
  Pair C code Short within Pair
  Pair C, fault length: 0.80m
  Pair D code OK

  mx8mm-ksz9131-a-b-connected$ ethtool --cable-test eth0
  Pair A code OK
  Pair B code OK
  Pair C code Short within Pair
  Pair C, fault length: 0.00m
  Pair D code Short within Pair
  Pair D, fault length: 0.00m

Tested on R8A77951 Salvator-XS with KSZ9031RNX and all four pairs connected:
(note: Cable test started/completed messages are omitted)

  r8a7795-ksz9031-all-connected$ ethtool --cable-test eth0
  Pair A code OK
  Pair B code OK
  Pair C code OK
  Pair D code OK

The CTRL1000 CTL1000_ENABLE_MASTER and CTL1000_AS_MASTER bits are not
restored by calling phy_init_hw(), they must be manually cached in
ksz9x31_cable_test_start() and restored at the end of
ksz9x31_cable_test_get_status().

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Oleksij Rempel <linux@rempel-privat.de>
Cc: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20220407105534.85833-1-marex@denx.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Marek Vasut authored and Jakub Kicinski committed Apr 8, 2022
1 parent 85b15c2 commit 58389c0
Showing 1 changed file with 221 additions and 0 deletions.
221 changes: 221 additions & 0 deletions drivers/net/phy/micrel.c
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Original file line number Diff line number Diff line change
Expand Up @@ -70,6 +70,27 @@
#define KSZ8081_LMD_SHORT_INDICATOR BIT(12)
#define KSZ8081_LMD_DELTA_TIME_MASK GENMASK(8, 0)

#define KSZ9x31_LMD 0x12
#define KSZ9x31_LMD_VCT_EN BIT(15)
#define KSZ9x31_LMD_VCT_DIS_TX BIT(14)
#define KSZ9x31_LMD_VCT_PAIR(n) (((n) & 0x3) << 12)
#define KSZ9x31_LMD_VCT_SEL_RESULT 0
#define KSZ9x31_LMD_VCT_SEL_THRES_HI BIT(10)
#define KSZ9x31_LMD_VCT_SEL_THRES_LO BIT(11)
#define KSZ9x31_LMD_VCT_SEL_MASK GENMASK(11, 10)
#define KSZ9x31_LMD_VCT_ST_NORMAL 0
#define KSZ9x31_LMD_VCT_ST_OPEN 1
#define KSZ9x31_LMD_VCT_ST_SHORT 2
#define KSZ9x31_LMD_VCT_ST_FAIL 3
#define KSZ9x31_LMD_VCT_ST_MASK GENMASK(9, 8)
#define KSZ9x31_LMD_VCT_DATA_REFLECTED_INVALID BIT(7)
#define KSZ9x31_LMD_VCT_DATA_SIG_WAIT_TOO_LONG BIT(6)
#define KSZ9x31_LMD_VCT_DATA_MASK100 BIT(5)
#define KSZ9x31_LMD_VCT_DATA_NLP_FLP BIT(4)
#define KSZ9x31_LMD_VCT_DATA_LO_PULSE_MASK GENMASK(3, 2)
#define KSZ9x31_LMD_VCT_DATA_HI_PULSE_MASK GENMASK(1, 0)
#define KSZ9x31_LMD_VCT_DATA_MASK GENMASK(7, 0)

/* Lan8814 general Interrupt control/status reg in GPHY specific block. */
#define LAN8814_INTC 0x18
#define LAN8814_INTS 0x1B
Expand Down Expand Up @@ -280,6 +301,7 @@ struct kszphy_priv {
struct kszphy_ptp_priv ptp_priv;
const struct kszphy_type *type;
int led_mode;
u16 vct_ctrl1000;
bool rmii_ref_clk_sel;
bool rmii_ref_clk_sel_val;
u64 stats[ARRAY_SIZE(kszphy_hw_stats)];
Expand Down Expand Up @@ -1326,6 +1348,199 @@ static int ksz9031_read_status(struct phy_device *phydev)
return 0;
}

static int ksz9x31_cable_test_start(struct phy_device *phydev)
{
struct kszphy_priv *priv = phydev->priv;
int ret;

/* KSZ9131RNX, DS00002841B-page 38, 4.14 LinkMD (R) Cable Diagnostic
* Prior to running the cable diagnostics, Auto-negotiation should
* be disabled, full duplex set and the link speed set to 1000Mbps
* via the Basic Control Register.
*/
ret = phy_modify(phydev, MII_BMCR,
BMCR_SPEED1000 | BMCR_FULLDPLX |
BMCR_ANENABLE | BMCR_SPEED100,
BMCR_SPEED1000 | BMCR_FULLDPLX);
if (ret)
return ret;

/* KSZ9131RNX, DS00002841B-page 38, 4.14 LinkMD (R) Cable Diagnostic
* The Master-Slave configuration should be set to Slave by writing
* a value of 0x1000 to the Auto-Negotiation Master Slave Control
* Register.
*/
ret = phy_read(phydev, MII_CTRL1000);
if (ret < 0)
return ret;

/* Cache these bits, they need to be restored once LinkMD finishes. */
priv->vct_ctrl1000 = ret & (CTL1000_ENABLE_MASTER | CTL1000_AS_MASTER);
ret &= ~(CTL1000_ENABLE_MASTER | CTL1000_AS_MASTER);
ret |= CTL1000_ENABLE_MASTER;

return phy_write(phydev, MII_CTRL1000, ret);
}

static int ksz9x31_cable_test_result_trans(u16 status)
{
switch (FIELD_GET(KSZ9x31_LMD_VCT_ST_MASK, status)) {
case KSZ9x31_LMD_VCT_ST_NORMAL:
return ETHTOOL_A_CABLE_RESULT_CODE_OK;
case KSZ9x31_LMD_VCT_ST_OPEN:
return ETHTOOL_A_CABLE_RESULT_CODE_OPEN;
case KSZ9x31_LMD_VCT_ST_SHORT:
return ETHTOOL_A_CABLE_RESULT_CODE_SAME_SHORT;
case KSZ9x31_LMD_VCT_ST_FAIL:
fallthrough;
default:
return ETHTOOL_A_CABLE_RESULT_CODE_UNSPEC;
}
}

static bool ksz9x31_cable_test_failed(u16 status)
{
int stat = FIELD_GET(KSZ9x31_LMD_VCT_ST_MASK, status);

return stat == KSZ9x31_LMD_VCT_ST_FAIL;
}

static bool ksz9x31_cable_test_fault_length_valid(u16 status)
{
switch (FIELD_GET(KSZ9x31_LMD_VCT_ST_MASK, status)) {
case KSZ9x31_LMD_VCT_ST_OPEN:
fallthrough;
case KSZ9x31_LMD_VCT_ST_SHORT:
return true;
}
return false;
}

static int ksz9x31_cable_test_fault_length(struct phy_device *phydev, u16 stat)
{
int dt = FIELD_GET(KSZ9x31_LMD_VCT_DATA_MASK, stat);

/* KSZ9131RNX, DS00002841B-page 38, 4.14 LinkMD (R) Cable Diagnostic
*
* distance to fault = (VCT_DATA - 22) * 4 / cable propagation velocity
*/
if ((phydev->phy_id & MICREL_PHY_ID_MASK) == PHY_ID_KSZ9131)
dt = clamp(dt - 22, 0, 255);

return (dt * 400) / 10;
}

static int ksz9x31_cable_test_wait_for_completion(struct phy_device *phydev)
{
int val, ret;

ret = phy_read_poll_timeout(phydev, KSZ9x31_LMD, val,
!(val & KSZ9x31_LMD_VCT_EN),
30000, 100000, true);

return ret < 0 ? ret : 0;
}

static int ksz9x31_cable_test_get_pair(int pair)
{
static const int ethtool_pair[] = {
ETHTOOL_A_CABLE_PAIR_A,
ETHTOOL_A_CABLE_PAIR_B,
ETHTOOL_A_CABLE_PAIR_C,
ETHTOOL_A_CABLE_PAIR_D,
};

return ethtool_pair[pair];
}

static int ksz9x31_cable_test_one_pair(struct phy_device *phydev, int pair)
{
int ret, val;

/* KSZ9131RNX, DS00002841B-page 38, 4.14 LinkMD (R) Cable Diagnostic
* To test each individual cable pair, set the cable pair in the Cable
* Diagnostics Test Pair (VCT_PAIR[1:0]) field of the LinkMD Cable
* Diagnostic Register, along with setting the Cable Diagnostics Test
* Enable (VCT_EN) bit. The Cable Diagnostics Test Enable (VCT_EN) bit
* will self clear when the test is concluded.
*/
ret = phy_write(phydev, KSZ9x31_LMD,
KSZ9x31_LMD_VCT_EN | KSZ9x31_LMD_VCT_PAIR(pair));
if (ret)
return ret;

ret = ksz9x31_cable_test_wait_for_completion(phydev);
if (ret)
return ret;

val = phy_read(phydev, KSZ9x31_LMD);
if (val < 0)
return val;

if (ksz9x31_cable_test_failed(val))
return -EAGAIN;

ret = ethnl_cable_test_result(phydev,
ksz9x31_cable_test_get_pair(pair),
ksz9x31_cable_test_result_trans(val));
if (ret)
return ret;

if (!ksz9x31_cable_test_fault_length_valid(val))
return 0;

return ethnl_cable_test_fault_length(phydev,
ksz9x31_cable_test_get_pair(pair),
ksz9x31_cable_test_fault_length(phydev, val));
}

static int ksz9x31_cable_test_get_status(struct phy_device *phydev,
bool *finished)
{
struct kszphy_priv *priv = phydev->priv;
unsigned long pair_mask = 0xf;
int retries = 20;
int pair, ret, rv;

*finished = false;

/* Try harder if link partner is active */
while (pair_mask && retries--) {
for_each_set_bit(pair, &pair_mask, 4) {
ret = ksz9x31_cable_test_one_pair(phydev, pair);
if (ret == -EAGAIN)
continue;
if (ret < 0)
return ret;
clear_bit(pair, &pair_mask);
}
/* If link partner is in autonegotiation mode it will send 2ms
* of FLPs with at least 6ms of silence.
* Add 2ms sleep to have better chances to hit this silence.
*/
if (pair_mask)
usleep_range(2000, 3000);
}

/* Report remaining unfinished pair result as unknown. */
for_each_set_bit(pair, &pair_mask, 4) {
ret = ethnl_cable_test_result(phydev,
ksz9x31_cable_test_get_pair(pair),
ETHTOOL_A_CABLE_RESULT_CODE_UNSPEC);
}

*finished = true;

/* Restore cached bits from before LinkMD got started. */
rv = phy_modify(phydev, MII_CTRL1000,
CTL1000_ENABLE_MASTER | CTL1000_AS_MASTER,
priv->vct_ctrl1000);
if (rv)
return rv;

return ret;
}

static int ksz8873mll_config_aneg(struct phy_device *phydev)
{
return 0;
Expand Down Expand Up @@ -2806,6 +3021,7 @@ static struct phy_driver ksphy_driver[] = {
.phy_id = PHY_ID_KSZ9031,
.phy_id_mask = MICREL_PHY_ID_MASK,
.name = "Micrel KSZ9031 Gigabit PHY",
.flags = PHY_POLL_CABLE_TEST,
.driver_data = &ksz9021_type,
.probe = kszphy_probe,
.get_features = ksz9031_get_features,
Expand All @@ -2819,6 +3035,8 @@ static struct phy_driver ksphy_driver[] = {
.get_stats = kszphy_get_stats,
.suspend = kszphy_suspend,
.resume = kszphy_resume,
.cable_test_start = ksz9x31_cable_test_start,
.cable_test_get_status = ksz9x31_cable_test_get_status,
}, {
.phy_id = PHY_ID_LAN8814,
.phy_id_mask = MICREL_PHY_ID_MASK,
Expand Down Expand Up @@ -2853,6 +3071,7 @@ static struct phy_driver ksphy_driver[] = {
.phy_id_mask = MICREL_PHY_ID_MASK,
.name = "Microchip KSZ9131 Gigabit PHY",
/* PHY_GBIT_FEATURES */
.flags = PHY_POLL_CABLE_TEST,
.driver_data = &ksz9021_type,
.probe = kszphy_probe,
.config_init = ksz9131_config_init,
Expand All @@ -2863,6 +3082,8 @@ static struct phy_driver ksphy_driver[] = {
.get_stats = kszphy_get_stats,
.suspend = kszphy_suspend,
.resume = kszphy_resume,
.cable_test_start = ksz9x31_cable_test_start,
.cable_test_get_status = ksz9x31_cable_test_get_status,
}, {
.phy_id = PHY_ID_KSZ8873MLL,
.phy_id_mask = MICREL_PHY_ID_MASK,
Expand Down

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