From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.dvmed.net (srv5.dvmed.net [207.36.208.214]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id B1E17DDDEE for ; Mon, 17 Mar 2008 23:08:43 +1100 (EST) Message-ID: <47DE5F43.80604@garzik.org> Date: Mon, 17 Mar 2008 08:08:35 -0400 From: Jeff Garzik MIME-Version: 1.0 To: Stefan Roese Subject: Re: [PATCH] net: NEWEMAC: Support for Pause packets in EMAC driver References: <1205488348-22536-1-git-send-email-sr@denx.de> In-Reply-To: <1205488348-22536-1-git-send-email-sr@denx.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: netdev@vger.kernel.org, linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Stefan Roese wrote: > From: Pravin M. Bathija > > Problem Description and Fix > --------------------------- > When a pause packet(with destination as reserved Multicast address) is > received by the EMAC hardware to control the flow of frames being > transmitted by it, it is dropped by the hardware unless the reserved > Multicast address is hashed in to the GAHT[1-4] registers. This code fix > adds the default reserved multicast address to the GAHT[1-4] registers > in the EMAC(s) present on the chip. The flow control with Pause packets > will only work if the following register bits are programmed in EMAC: > EMACx_MR1[APP] = 1 > EMACx_RMR[BAE] = 1 > EMACx_RMR[MAE] = 1 > > Behavior that may be observed in a running system > ------------------------------------------------- > A host transferring data from a PPC based system may send a Pause packet > to the PPC EMAC requesting it to slow down the flow of packets. If the > default reserved multicast MAC address is not programmed into the > GAHT[1-4] registers this Pause packet will be dropped by PPC EMAC and no > Flow Control will be done. > > Signed-off-by: Pravin M. Bathija > Signed-off-by: Stefan Roese > --- > drivers/net/ibm_newemac/core.c | 7 +++++++ > 1 files changed, 7 insertions(+), 0 deletions(-) applied