PROBLEM: PHY probe not working properly for ibm_emac (PPC4xx)

[Hynek Petrak]

[1.] One line summary of the problem:   

PHY probe not working properly for ibm_emac (PPC4xx)
 
[2.] Full description of the problem/report:

I have a system with AMCC PowerPC 405EP and PHY Intel LXT971A.
Linux 2.6.18.3 is not able to detect the PHY ID correctly. The 
PHY ID detected is 0, but should be 0x1d. 

This is because phy_read() (__emac_mdio_read() resp.) from 
drivers/net/ibm_emac/ibm_emac_core.c might return -ETIMEDOUT 
or -EREMOTEIO on error. This is ignored inside the 

int mii_phy_probe(struct mii_phy *phy, int address) 
from drivers/net/ibm_emac/ibm_emac_phy.c

as the return value is assigned to an u32 variable.
Please consider the patch below ... 

[3.] Keywords:

networking, kernel, problem, ibm_emac, ppc4xx, phy

[4.] Kernel version (from /proc/version):

2.6.18.3

[5.] Output of Oops.. message (if applicable) with symbolic 
information resolved (see Documentation/oops-tracing.txt)

doesn't oops


[6.] A small shell script or example program which triggers the
     problem (if possible)

none required

[7.] Environment
[7.1.] Software (add the output of the ver_linux script here)

ELDK 3.1.1 from www.denx.org

[7.2.] Processor information (from /proc/cpuinfo):

AMCC' PowerPC 405EP

PHY Intel LXT971A

[X.] Patch:

Index: drivers/net/ibm_emac/ibm_emac_phy.c
===================================================================
--- drivers/net/ibm_emac/ibm_emac_phy.c (revision 67)
+++ drivers/net/ibm_emac/ibm_emac_phy.c (revision 69)
@@ -309,7 +309,7 @@
 {
        struct mii_phy_def *def;
        int i;
-       u32 id;
+       int id;

        phy->autoneg = AUTONEG_DISABLE;
        phy->advertising = 0;
@@ -324,6 +324,8 @@

        /* Read ID and find matching entry */
        id = (phy_read(phy, MII_PHYSID1) << 16) | phy_read(phy, 
MII_PHYSID2);
+        if (id < 0)
+            return -ENODEV;
        for (i = 0; (def = mii_phy_table[i]) != NULL; i++)
                if ((id & def->phy_id_mask) == def->phy_id)
                        break;


-- 
Mgr. Hynek Petrak
-----------------
S.W.A.C. Bohemia spol. s r.o.
Heydukova 314, 38601 Strakonice
tel: +420 3834181-36 or +49 (89) 613866-51 
PGP key: http://www.swac.cz/~hynek/hp.pgp
5CAC 7712 CFFD D076 0D74 A134 1EFD 728C 84CB 94CF

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