Re: [PATCH] net/phy: tune get_phy_c45_ids to support more c45 phy

From: David Miller
Date: Sun Apr 12 2015 - 20:42:09 EST


From: Shengzhou Liu <Shengzhou.Liu@xxxxxxxxxxxxx>
Date: Fri, 10 Apr 2015 17:10:20 +0800

> if ((c45_ids->devices_in_package & 0x1fffffff) == 0x1fffffff) {
> - *phy_id = 0xffffffff;
> - return 0;
> + reg_addr = MII_ADDR_C45 | 0 << 16 | 6;
> + phy_reg = mdiobus_read(bus, addr, reg_addr);
> + if (phy_reg < 0)
> + return -EIO;

Why are you reading this same register again, and why are you doing
it with the magic constant "6". That's not '6', it's 'MDIO_DEVS2'.

The first loop executed here should have read from this address, and
placed the value into the ->devices_in_package.

> + c45_ids->devices_in_package = (phy_reg & 0xffff) << 16;
> + reg_addr = MII_ADDR_C45 | 0 << 16 | 5;

Again, this isn't '5', it's 'MDIO_DEVS1'.

This looks really like a hack. You're reading again the same registers,
by hand, that the loop should already be reading properly.

Why not restructure the loop to actually probe naturally for the
presence bits in a way that works on the chip you are trying to make
work?
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