netdev - Re: [PATCH 2/2] net: calexdaxgmac: fixup endian issues after _

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Message-ID: <1360606656.2701.18.camel@bwh-desktop.uk.solarflarecom.com>
Date:	Mon, 11 Feb 2013 18:17:36 +0000
From:	Ben Hutchings <bhutchings@...arflare.com>
To:	Ben Dooks <ben.dooks@...ethink.co.uk>
CC:	<netdev@...r.kernel.org>, "David S. Miller" <davem@...emloft.net>,
	Rob Herring <rob.herring@...xeda.com>,
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 2/2] net: calexdaxgmac: fixup endian issues after __raw
 IO function change

On Sun, 2013-02-10 at 15:38 +0000, Ben Dooks wrote:
> When changing to __raw acccessors in 0ec6d343f7bcf9e0944aa9ff65287b987ec00c0f
> ("net: calxedaxgmac: use raw i/o accessors in rx and tx paths"), the driver
> is now broken on big endian systems as the readl/writel have an implict
> endian swap in them.
> 
> Change all the places where the __raw calls are used to correctly convert
> the constants in big endian format to the little endian data that the
> peripheral expects to see.

You are using le32_to_cpu() and cpu_to_le32() the wrong way round, and
then putting casts on the wrong side, i.e. it should be:

	value = le32_to_cpu((__force __le32)__raw_readl(addr));
	__raw_writel((__force u32)cpu_to_le32(value), addr);

(I do wonder why __raw I/O functions aren't declared to take/return __le
types... it would avoid the need to cast altogether.)

> Signed-off-by: Ben Dooks <ben.dooks@...ethink.co.uk>
> ---
>  drivers/net/ethernet/calxeda/xgmac.c |   10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/calxeda/xgmac.c b/drivers/net/ethernet/calxeda/xgmac.c
> index f91d9b2..96fd538 100644
> --- a/drivers/net/ethernet/calxeda/xgmac.c
> +++ b/drivers/net/ethernet/calxeda/xgmac.c
> @@ -1202,7 +1202,8 @@ static int xgmac_poll(struct napi_struct *napi, int budget)
>  
>  	if (work_done < budget) {
>  		napi_complete(napi);
> -		__raw_writel(DMA_INTR_DEFAULT_MASK, priv->base + XGMAC_DMA_INTR_ENA);
> +		__raw_writel(le32_to_cpu((__force __le32)DMA_INTR_DEFAULT_MASK),
> +			     priv->base + XGMAC_DMA_INTR_ENA);
>  	}
>  	return work_done;
>  }
> @@ -1348,7 +1349,7 @@ static irqreturn_t xgmac_pmt_interrupt(int irq, void *dev_id)
>  	void __iomem *ioaddr = priv->base;
>  
>  	intr_status = __raw_readl(ioaddr + XGMAC_INT_STAT);
> -	if (intr_status & XGMAC_INT_STAT_PMT) {
> +	if (intr_status & le32_to_cpu((__force __le32)XGMAC_INT_STAT_PMT)) {
>  		netdev_dbg(priv->dev, "received Magic frame\n");
>  		/* clear the PMT bits 5 and 6 by reading the PMT */
>  		readl(ioaddr + XGMAC_PMT);
> @@ -1369,6 +1370,8 @@ static irqreturn_t xgmac_interrupt(int irq, void *dev_id)
>  	intr_status &= __raw_readl(priv->base + XGMAC_DMA_INTR_ENA);
>  	__raw_writel(intr_status, priv->base + XGMAC_DMA_STATUS);
>  
> +	intr_status = (__force u32)cpu_to_le32(intr_status);

Perhaps intr_status should be split into two variables, for native and
little-endian order.

Ben.

>  	/* It displays the DMA process states (CSR5 register) */
>  	/* ABNORMAL interrupts */
>  	if (unlikely(intr_status & DMA_STATUS_AIS)) {
> @@ -1403,7 +1406,8 @@ static irqreturn_t xgmac_interrupt(int irq, void *dev_id)
>  
>  	/* TX/RX NORMAL interrupts */
>  	if (intr_status & (DMA_STATUS_RI | DMA_STATUS_TU | DMA_STATUS_TI)) {
> -		__raw_writel(DMA_INTR_ABNORMAL, priv->base + XGMAC_DMA_INTR_ENA);
> +		__raw_writel(le32_to_cpu((__force __le32)DMA_INTR_ABNORMAL),
> +			     priv->base + XGMAC_DMA_INTR_ENA);
>  		napi_schedule(&priv->napi);
>  	}
>  

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

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