From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean-Christophe PLAGNIOL-VILLARD Date: Thu, 29 Jan 2009 00:13:47 +0100 Subject: [U-Boot] [PATCH v2 5/9] AVR32: macb - Disable 100mbps if clock is slow In-Reply-To: <20090128224207.48b6ba69@hskinnemoen-d830> References: <7e5f5fd7693284246714c42b6a3014f82f670b82.1232710611.git.gunnar@rangoy.com> <20090123153856.GA16585@game.jcrosoft.org> <20090128172322.GC8355@game.jcrosoft.org> <20090128224207.48b6ba69@hskinnemoen-d830> Message-ID: <20090128231347.GD8355@game.jcrosoft.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 22:42 Wed 28 Jan , Haavard Skinnemoen wrote: > Jean-Christophe PLAGNIOL-VILLARD wrote: > > > On the EVK1100 board, the CPU (UC3A0512) is connected to the PHY via an > > > RMII bus. This requires the CPU clock to be at least 50 MHz. > > > Unfortunately, the chip on current EVK1100 boards may be unable to run > > > at more than 50 MHz, and with the oscillator on the board, the closest > > > frequency we can generate is 48 MHz. > > IMHO It's a HW design error to not use the MII > > Some people want to use the extra pins for other things... make sense so I'll put a 10Mpbs phy personnaly instead or a 10/100 that can be put in a 10 mode instead to avoid to manage it in the code > > Unfortunately, there are quite a few boards with early engineering > samples around, and they have various issues. The chips that are in > production are capable of running fast enough to support RMII. > > > > This patch makes it possible to limit the macb to 10 MBit for this > > > case. We are open for suggestions for other solutions. > > I guest you may need to disable the phy auto config mode and force him to be > > see as a 10Mbps phy evenif it's a 10/100 > > No need to disable autonegotiation -- you still want to select between > half an full duplex, for example. But you'll need to limit the > available options to the ones that actually work. I do not mean the autoneg but to specify to the phy, if possible, to never accept the 100Mps instead of do it in the code > > That said, I kind of like Ben's suggestion -- it's a more general > solution to all sorts of board/phy/chip/whatever limitations. > > As for a better name, how about CONFIG_MACB_ADVERTISE? why not Best Regards, J.