Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752284AbbBXH1t (ORCPT ); Tue, 24 Feb 2015 02:27:49 -0500 Received: from mail-ig0-f175.google.com ([209.85.213.175]:37739 "EHLO mail-ig0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750748AbbBXH1r convert rfc822-to-8bit (ORCPT ); Tue, 24 Feb 2015 02:27:47 -0500 MIME-Version: 1.0 In-Reply-To: <54EB3B58.2050903@atmel.com> References: <1424258975-28611-1-git-send-email-achandran@mvista.com> <54E5D5A0.90005@monstr.eu> <54EB3B58.2050903@atmel.com> Date: Tue, 24 Feb 2015 12:57:45 +0530 Message-ID: Subject: Re: [PATCH] net: macb: Add big endian CPU support From: Arun Chandran To: Nicolas Ferre Cc: Michal Simek , netdev , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3315 Lines: 74 On Mon, Feb 23, 2015 at 8:08 PM, Nicolas Ferre wrote: > Le 20/02/2015 12:45, Arun Chandran a écrit : >> On Thu, Feb 19, 2015 at 5:52 PM, Michal Simek wrote: >>> >>> On 02/18/2015 12:29 PM, Arun Chandran wrote: >>>> This patch converts all __raw_readl and __raw_writel function calls >>>> to their corresponding readl_relaxed and writel_relaxed variants. >>>> >>>> It also tells the driver to set ahb_endian_swp_mgmt_en bit in dma_cfg >>>> when the CPU is configured in big endian mode. >>>> >>>> Signed-off-by: Arun Chandran >>>> --- >>>> This patch is tested on xilinx ZC702 evaluation board with >>>> CONFIG_CPU_BIG_ENDIAN=y and booting NFS rootfs >>>> --- >>>> --- >>>> drivers/net/ethernet/cadence/macb.c | 18 ++++++++++++------ >>>> drivers/net/ethernet/cadence/macb.h | 15 ++++++++------- >>>> 2 files changed, 20 insertions(+), 13 deletions(-) >>>> >>>> diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c >>>> index ad76b8e..05fb36d 100644 >>>> --- a/drivers/net/ethernet/cadence/macb.c >>>> +++ b/drivers/net/ethernet/cadence/macb.c >>>> @@ -449,7 +449,7 @@ static void macb_update_stats(struct macb *bp) >>>> WARN_ON((unsigned long)(end - p - 1) != (MACB_TPF - MACB_PFR) / 4); >>>> >>>> for(; p < end; p++, reg++) >>>> - *p += __raw_readl(reg); >>>> + *p += readl_relaxed(reg); >>>> } >>>> >>>> static int macb_halt_tx(struct macb *bp) >>>> @@ -1585,7 +1585,11 @@ static void macb_configure_dma(struct macb *bp) >>>> if (bp->dma_burst_length) >>>> dmacfg = GEM_BFINS(FBLDO, bp->dma_burst_length, dmacfg); >>>> dmacfg |= GEM_BIT(TXPBMS) | GEM_BF(RXBMS, -1L); >>>> - dmacfg &= ~GEM_BIT(ENDIA); >>>> + dmacfg &= ~GEM_BIT(ENDIA_PKT); >>>> + /* Tell the chip to byteswap descriptors on big-endian hosts */ >>>> +#ifdef __BIG_ENDIAN >>>> + dmacfg |= GEM_BIT(ENDIA_DESC); >>>> +#endif >>> >>> I don't think this is the best way what you should do. >>> Instead of having this ifdef here you should find out any reg and detect if the IP >>> is in big endian or little endian mode. I have done it for some xilinx IPs which >>> can run on big or little endian system. >>> In general find reg which some field which has some meaning - write there 1 >>> and read expected value and based on that decide if you are on big or little endian system. >> >> Hi Michal, >> >> I was not able to find any such registers for GEM in the TRM >> http://www.xilinx.com/support/documentation/user_guides/ug585-Zynq-7000-TRM.pdf >> >> I tried writing to dma_cfg (0x00000010) and reading from design_cfg5 >> (0x00000290) >> Its not reflecting anything(design_cfg5 always reads same value); It >> is not helping. > > 0kay, here you mean that the design_cfg5 (@0x290) and its bit 16:15 > "gem_endian_swap_def" doesn't change depending on the big/little endian > configuration you use? Yes. That register always reads the same. -- Arun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/