From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Mike Frysinger" Subject: Re: [PATCH 1/3] Blackfin ethernet driver: on chip ethernet MAC controller driver Date: Sat, 14 Jul 2007 16:38:20 -0400 Message-ID: <8bd0f97a0707141338q996f246p6abdc2f65efa5e7@mail.gmail.com> References: <1184438993.3140.23.camel@roc-laptop> <200707142138.36619.mb@bu3sch.de> <8bd0f97a0707141249y2c90a59cs356aa3cef357f721@mail.gmail.com> <200707142217.36361.mb@bu3sch.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: bryan.wu@analog.com, "Jeff Garzik" , LKML , netdev@vger.kernel.org, "Andrew Morton" To: "Michael Buesch" Return-path: Received: from an-out-0708.google.com ([209.85.132.244]:20352 "EHLO an-out-0708.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762205AbXGNUiU (ORCPT ); Sat, 14 Jul 2007 16:38:20 -0400 Received: by an-out-0708.google.com with SMTP id d31so159653and for ; Sat, 14 Jul 2007 13:38:20 -0700 (PDT) In-Reply-To: <200707142217.36361.mb@bu3sch.de> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 7/14/07, Michael Buesch wrote: > On Saturday 14 July 2007 21:49:21 Mike Frysinger wrote: > > On 7/14/07, Michael Buesch wrote: > > > On Saturday 14 July 2007 20:49:53 Bryan Wu wrote: > > > > +static int __init bf537mac_probe(struct net_device *dev) > > > > +{ > > > > + struct bf537mac_local *lp = netdev_priv(dev); > > > > + int retval; > > > > + > > > > + /* Grab the MAC address in the MAC */ > > > > + *(u32 *) (&(dev->dev_addr[0])) = bfin_read_EMAC_ADDRLO(); > > > > + *(u16 *) (&(dev->dev_addr[4])) = (u16) bfin_read_EMAC_ADDRHI(); > > > > > > Endianess broken. > > > > > > > +struct dma_config_reg { > > > > + unsigned short b_DMA_EN:1; /* Bit 0 : DMA Enable */ > > > > + unsigned short b_WNR:1; /* Bit 1 : DMA Direction */ > > > > + unsigned short b_WDSIZE:2; /* Bit 2 & 3 : DMA Tranfer Word size */ > > > > + unsigned short b_DMA2D:1; /* Bit 4 : DMA Mode 2D or 1D */ > > > > + unsigned short b_RESTART:1; /* Bit 5 : Retain the FIFO */ > > > > + unsigned short b_DI_SEL:1; /* Bit 6 : Data Interrupt Timing Select */ > > > > + unsigned short b_DI_EN:1; /* Bit 7 : Data Interrupt Enable */ > > > > + unsigned short b_NDSIZE:4; /* Bit 8 to 11 : Flex descriptor Size */ > > > > + unsigned short b_FLOW:3; /* Bit 12 to 14 : FLOW */ > > > > +}; > > > > > > This is most likely not endianess safe. > > > > do we really need to care about this ? this is a driver for a MAC > > which can only be found on Blackfin processors and Blackfin itself is > > only little endian. > > Well, this bitfield _might_ be OK (although I don't like bitfields > at all), but the above pointer casting stuff should really use > leXX_to_cpu. It's so easy to use and it is easier to read and > maintain the code afterwards. i think that's arguable ... i dont see how: a = foo(b); is easier to read than: a = b; but it is easy to use ... i guess my point was more along the lines of wasting further time auditing a driver for endianness issues that will never actually be an issue. -mike