Signed-off-by: Wolfgang Denk <w...@denx.de> Cc: Grant Likely <grant.lik...@secretlab.ca> Cc: John Rigby <jcri...@gmail.com> --- This patch is NOT intended for inclusion into mainline, but rather a request for help. For some reason which I don't understand yet, the Ethernet interface on the ARIA board does not work in the default configuration, because MII probing fails.
What I'm seeing is this; the problem is with this part of code in "drivers/net/fs_enet/mii-fec.c": 156 fec->mii_speed = ((ppc_proc_freq + 4999999) / 5000000) << 1; ... 163 out_be32(&fec->fecp->fec_mii_speed, fec->mii_speed); I added some debug messages, and this is what I see: On the ADS5121, we have the CPU clocked at 400 MHz. I get: ... ## ppc_proc_freq = 399999996, fec->mii_speed = 160 FEC MII Bus: probed ... It works fine. According to the Ref. Man.: A value of 0 in this field turns off the MDC and leaves it in a low-voltage state. Any non-zero value results in the MDC frequency of 1/(mii_speed*2) of the system clock frequency. that means we have a MDC frequency of 400 MHz / (2 * 160) = 1.25 MHz which is obviously within the 2.5 MHz limit. Now ARIA is currently running at 316.8 MHz, and this is what I get: ... ## ppc_proc_freq = 316800000, fec->mii_speed = 128 fsl-fec-mdio: probe of 80002800.mdio failed with error -5 ... It fails. MDC frequency is 316.8 MHz / (2 * 128) = 1.24 MHz which should be fine. However, If I change the code to fec->mii_speed = (((ppc_proc_freq / 1000000) / 30) + 1) << 1; then I get: ... ## ppc_proc_freq = 316800000, fec->mii_speed = 22 FEC MII Bus: probed ... and it's working!!! However, I compute MDC frequency as 316.8 MHz / (2 * 22) = 7.2 MHz which is far above the maximum allowed clock of 2.5 MHz ??? Has anybody any idea what might be going on here? drivers/net/fs_enet/mii-fec.c | 6 +++++- 1 files changed, 5 insertions(+), 1 deletions(-) diff --git a/drivers/net/fs_enet/mii-fec.c b/drivers/net/fs_enet/mii-fec.c index 9d8bd97..a51dd83 100644 --- a/drivers/net/fs_enet/mii-fec.c +++ b/drivers/net/fs_enet/mii-fec.c @@ -153,8 +153,12 @@ static int __devinit fs_enet_mdio_probe(struct of_device *ofdev, if (!fec->fecp) goto out_fec; +#if 0 fec->mii_speed = ((ppc_proc_freq + 4999999) / 5000000) << 1; - +#else + fec->mii_speed = (((ppc_proc_freq / 1000000) / 30) + 1) << 1; + printk("## ppc_proc_freq = %d, fec->mii_speed = %d\n", ppc_proc_freq, fec->mii_speed); +#endif setbits32(&fec->fecp->fec_r_cntrl, FEC_RCNTRL_MII_MODE); setbits32(&fec->fecp->fec_ecntrl, FEC_ECNTRL_PINMUX | FEC_ECNTRL_ETHER_EN); -- 1.6.0.6 _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev