tree f60a5251870fbb44e4e2fac0862fde9d81350e14
parent 749c08f8206cdf5cad15d557912898ce22aa55da
author Vladimir Oltean <vladimir.oltean@nxp.com> 1595266014 +0300
committer David S. Miller <davem@davemloft.net> 1595462496 -0700

net: phy: fix check in get_phy_c45_ids

After the patch below, the iteration through the available MMDs is
completely short-circuited, and devs_in_pkg remains set to the initial
value of zero.

Due to devs_in_pkg being zero, the rest of get_phy_c45_ids() is
short-circuited too: the following loop never reaches below this point
either (it executes "continue" for every device in package, failing to
retrieve PHY ID for any of them):

	/* Now probe Device Identifiers for each device present. */
	for (i = 1; i < num_ids; i++) {
		if (!(devs_in_pkg & (1 << i)))
			continue;

So c45_ids->device_ids remains populated with zeroes. This causes an
Aquantia AQR412 PHY (same as any C45 PHY would, in fact) to be probed by
the Generic PHY driver.

The issue seems to be a case of submitting partially committed work (and
therefore testing something other than was submitted).

The intention of the patch was to delay exiting the loop until one more
condition is reached (the devs_in_pkg read from hardware is either 0, OR
mostly f's). So fix the patch to reflect that.

Tested with traffic on a LS1028A-QDS, the PHY is now probed correctly
using the Aquantia driver. The devs_in_pkg bit field is set to
0xe000009a, and the MMDs that are present have the following IDs:

[    5.600772] libphy: get_phy_c45_ids: device_ids[1]=0x3a1b662
[    5.618781] libphy: get_phy_c45_ids: device_ids[3]=0x3a1b662
[    5.630797] libphy: get_phy_c45_ids: device_ids[4]=0x3a1b662
[    5.654535] libphy: get_phy_c45_ids: device_ids[7]=0x3a1b662
[    5.791723] libphy: get_phy_c45_ids: device_ids[29]=0x3a1b662
[    5.804050] libphy: get_phy_c45_ids: device_ids[30]=0x3a1b662
[    5.816375] libphy: get_phy_c45_ids: device_ids[31]=0x0

[    7.690237] mscc_felix 0000:00:00.5: PHY [0.5:00] driver [Aquantia AQR412] (irq=POLL)
[    7.704739] mscc_felix 0000:00:00.5: PHY [0.5:01] driver [Aquantia AQR412] (irq=POLL)
[    7.718918] mscc_felix 0000:00:00.5: PHY [0.5:02] driver [Aquantia AQR412] (irq=POLL)
[    7.733044] mscc_felix 0000:00:00.5: PHY [0.5:03] driver [Aquantia AQR412] (irq=POLL)

Fixes: bba238ed037c ("net: phy: continue searching for C45 MMDs even if first returned ffff:ffff")
Reported-by: Colin King <colin.king@canonical.com>
Reported-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>