From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Grandegger Subject: Re: alchemy/gpr: au1000_eth regression with v2.6.37rc2 Date: Fri, 19 Nov 2010 11:29:45 +0100 Message-ID: <4CE65199.7030007@grandegger.com> References: <4CE58593.50509@grandegger.com> <201011182330.08488.florian@openwrt.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Linux-MIPS , Netdev@vger.kernel.org To: Florian Fainelli Return-path: In-Reply-To: <201011182330.08488.florian@openwrt.org> Sender: netdev-owner@vger.kernel.org List-ID: Hello Florian, On 11/18/2010 11:30 PM, Florian Fainelli wrote: > Hello Wolfgang, >=20 > Le Thursday 18 November 2010 20:59:15, Wolfgang Grandegger a =E9crit = : >> Hello, >> >> I just realized that the v2.6.37-rc2 kernel does not boot any more o= n >> the Alchemy GPR board. It works fine with v2.6.36. It hangs in the >> probe function of the au1000_eth driver when probing the second >> ethernet port (eth1): >> >> au1000_eth_mii: probed >> au1000-eth au1000-eth.0: (unregistered net_device): attached PHY d= river >> [Generic PHY] (mii_bus:phy_addr=3D0:00, irq=3D-1) au1000-eth au1000-= eth.0: >> eth0: Au1xx0 Ethernet found at 0x10500000, irq 35 au1000_eth: au1000= _eth >> version 1.7 Pete Popov ... hangs ... >> >> Similar messages should follow for eth1. I narrowed down (bisect'ed)= the >> problem to commit: >> >> commit d0e7cb5d401695809ba8c980124ab1d8c66efc8b >> Author: Florian Fainelli >> Date: Wed Sep 8 11:15:13 2010 +0000 >> >> au1000-eth: remove volatiles, switch to I/O accessors >> >> Remove all the volatile keywords where they were used, switch to= using >> the proper readl/writel accessors. >> >> Signed-off-by: Florian Fainelli >> Signed-off-by: David S. Miller >> >> The kernel actually hangs when accessing "&aup->mac->mii_control" in >> au1000_mdio_read(), but only for eth1. Any idea what does go wrong? >=20 > I do not understand so far while it hangs only for eth1. My device on= ly has=20 > one ethernet MAC, so I could not notice the problem. Looking at this = close,=20 > there are a couple of u32 const* usages in au1000_mdio_{read,write} w= hich are=20 > looking wrong to me now. Can you try to remove these? That did not help. >> In principle, I do not want to access the MII regs of the MAC becaus= e >> eth0 and eth1 are connected to switches. But that's not possible, ev= en >> with "aup->phy_static_config=3D1" and "aup->phy_addr=3D0". >=20 > If you think this is another issue, I will fix it in another patch. Accessing the MII registers of the MAC should not hang the system even if I do not need to. First I want to understand why. Looks like a wire= d optimizer issue. BTW: why do you use readl() and writel() instead of the usual au_readl(= ) and au_writel() to access memory mapped cpu registers? It did not help, anyway. Wolfgang