From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3E6D2AEC.5040409@mvista.com> Date: Mon, 10 Mar 2003 16:16:44 -0800 From: Todd Poynor MIME-Version: 1.0 To: Debbie Xu Cc: "'Linuxppc-Embedded'" Subject: Re: Linux-Support for IBM PPC405EP's EMACs References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Debbie Xu wrote: > Hi Todd, > > I found some confusing code for the PPC405EP's EMACs at the Linux kernel > (2.4.21-pre2). It is common to both EMACs. > > When the system is booting up, the ocp_enet_open() (in > drivers/net/ibm_ocp/ibm_ocp_enet.c) is called to open the 2 EMACs, one > at a time. However, the link status of the Ethernet ports, when it is > reported in the function mii_display_status() (in > drivers/net/ibm_ocp/ibm_ocp_phy.c),is controlled by a "link" variable in > an ocp_enet_private structure. Once a PHY is found at the probing time, > this "link" variable stays as "1" ("up" status) always. BUT, it doesn't > care if that Ethernet port is connected to any network or not. This > "link" status only reflects whether this EMAC is connected to a PHY > device or not. The definition of the ocp_enet_private structure (at > drivers/net/ibm_ocp/ibm_ocp_enet.h) doesn't tell much of the nature of > the"link" variable either. So, what shall we expect from this status > reporting? I tend to think that a link is only "up" when it's connected > on a network. > > Can you share your ideas on this? Hi, the code in question predates the recent 405EP changes, and I haven't looked at it recently. I have noticed that the link status for uncabled EMACs was defaulted to "up" (and with other values such as 10BT half-duplex). There's a rewrite of this driver in the works so maybe all this will change soon, otherwise it's something to be cleaned up someday. -- Todd ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/