Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Received-SPF: Pass (protection.outlook.com: domain of xilinx.com designates
 149.199.60.83 as permitted sender) receiver=protection.outlook.com;
 client-ip=149.199.60.83; helo=xsj-pvapsmtpgw01;
Date:   Wed, 19 Sep 2018 20:08:06 +0200
From:   "Edgar E. Iglesias" <edgar.iglesias@xilinx.com>
To:     Michal Simek <michal.simek@xilinx.com>
CC:     <linux-kernel@vger.kernel.org>, <monstr@monstr.eu>,
        "Edgar E. Iglesias" <edgari@xilinx.com>,
        "David S. Miller" <davem@davemloft.net>, <netdev@vger.kernel.org>,
        <u-boot@lists.denx.de>, Joe Hershberger <joe.hershberger@ni.com>,
        Nicolas Ferre <nicolas.ferre@microchip.com>
Subject: Re: [PATCH] net: macb: Clean 64b dma addresses if they are not
 detected
Message-ID: <20180919180806.3tps6yukhm3ry43i@toto>
References: <0997a0e77b5e5c04c9a4d277d702d93a1a8a7448.1537373294.git.michal.simek@xilinx.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <0997a0e77b5e5c04c9a4d277d702d93a1a8a7448.1537373294.git.michal.simek@xilinx.com>
User-Agent: NeoMutt/20170609 (1.8.3)
SpamDiagnosticOutput: 1:99
SpamDiagnosticMetadata: NSPM
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Sep 2018 18:08:17.2441
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: a167bb6e-47ad-4ba5-0cbc-08d61e5ae041
X-MS-Exchange-CrossTenant-Id: 657af505-d5df-48d0-8300-c31994686c5c
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=657af505-d5df-48d0-8300-c31994686c5c;Ip=[149.199.60.83];Helo=[xsj-pvapsmtpgw01]
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR02MB4758
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, Sep 19, 2018 at 06:08:18PM +0200, Michal Simek wrote:
> Clear ADDR64 dma bit in DMACFG register in case that HW_DMA_CAP_64B
> is not detected on 64bit system.
> The issue was observed when bootloader(u-boot) does not check macb
> feature at DCFG6 register (DAW64_OFFSET) and enabling 64bit dma support
> by default. Then macb driver is reading DMACFG register back and only
> adding 64bit dma configuration but not cleaning it out.
> 
> This is also align with other features which are also cleared if they are not
> present.

Hi Michal,

> 
> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> ---
> 
>  drivers/net/ethernet/cadence/macb_main.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index 16e4ef7d7185..79707dff3f13 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -2163,6 +2163,8 @@ static void macb_configure_dma(struct macb *bp)
>  #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
>  		if (bp->hw_dma_cap & HW_DMA_CAP_64B)
>  			dmacfg |= GEM_BIT(ADDR64);
> +		else
> +			dmacfg &= ~GEM_BIT(ADDR64);
>  #endif

I think you might want to do this clearing outside of the #ifdef.
If CONFIG_ARCH_DMA_ADDR_T_64BIT is not defined, we'd want to make
sure the ADDR64 is cleared. E.g something like:

             dmacfg &= ~GEM_BIT(ADDR64);
#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
             if (bp->hw_dma_cap & HW_DMA_CAP_64B)
                     dmacfg |= GEM_BIT(ADDR64);
#endif


Same thing for the USE_HWSTAMP/PTP flags below.

Best regards,
Edgar


>  #ifdef CONFIG_MACB_USE_HWSTAMP
>  		if (bp->hw_dma_cap & HW_DMA_CAP_PTP)
> -- 
> 1.9.1
>