[U-Boot] [PATCH 04/51] net: dwc: Make the cache handling less cryptic

[Chin Liang See]

On Sun, 2014-09-21 at 14:58 +0200, marex at denx.de wrote:
> Add a few new variables to make the cache handling less cryptic.
> Add a variable for DMA and DATA descriptor start and end, so the
> correctness of the code is easier to inspect.
> 
> Signed-off-by: Marek Vasut <marex at denx.de>
> Cc: Chin Liang See <clsee at altera.com>
> Cc: Dinh Nguyen <dinguyen at altera.com>
> Cc: Albert Aribaud <albert.u.boot at aribaud.net>
> Cc: Tom Rini <trini at ti.com>
> Cc: Wolfgang Denk <wd at denx.de>
> Cc: Pavel Machek <pavel at denx.de>
> Cc: Joe Hershberger <joe.hershberger at gmail.com>
> Acked-by: Pavel Machek <pavel at denx.de>
> ---
>  drivers/net/designware.c | 48 +++++++++++++++++++++++-------------------------
>  1 file changed, 23 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/net/designware.c b/drivers/net/designware.c
> index aaf146d..9ded895 100644
> --- a/drivers/net/designware.c
> +++ b/drivers/net/designware.c
> @@ -279,19 +279,21 @@ static int dw_eth_send(struct eth_device *dev, void *packet, int length)
>  	struct eth_dma_regs *dma_p = priv->dma_regs_p;
>  	u32 desc_num = priv->tx_currdescnum;
>  	struct dmamacdescr *desc_p = &priv->tx_mac_descrtable[desc_num];
> -
> +	uint32_t desc_start = (uint32_t)desc_p;
> +	uint32_t desc_end = desc_start +
> +		roundup(sizeof(*desc_p), ARCH_DMA_MINALIGN);
> +	uint32_t data_start = (uint32_t)desc_p->dmamac_addr;
> +	uint32_t data_end = data_start +
> +		roundup(length, ARCH_DMA_MINALIGN);
>  	/*
>  	 * Strictly we only need to invalidate the "txrx_status" field
>  	 * for the following check, but on some platforms we cannot
> -	 * invalidate only 4 bytes, so roundup to
> -	 * ARCH_DMA_MINALIGN. This is safe because the individual
> -	 * descriptors in the array are each aligned to
> -	 * ARCH_DMA_MINALIGN.
> +	 * invalidate only 4 bytes, so we flush the entire descriptor,
> +	 * which is 16 bytes in total. This is safe because the
> +	 * individual descriptors in the array are each aligned to
> +	 * ARCH_DMA_MINALIGN and padded appropriately.
>  	 */
> -	invalidate_dcache_range(
> -		(unsigned long)desc_p,
> -		(unsigned long)desc_p +
> -		roundup(sizeof(desc_p->txrx_status), ARCH_DMA_MINALIGN));
> +	invalidate_dcache_range(desc_start, desc_end);
>  
>  	/* Check if the descriptor is owned by CPU */
>  	if (desc_p->txrx_status & DESC_TXSTS_OWNBYDMA) {
> @@ -299,12 +301,10 @@ static int dw_eth_send(struct eth_device *dev, void *packet, int length)
>  		return -1;
>  	}
>  
> -	memcpy((void *)desc_p->dmamac_addr, packet, length);
> +	memcpy(desc_p->dmamac_addr, packet, length);
>  
>  	/* Flush data to be sent */
> -	flush_dcache_range((unsigned long)desc_p->dmamac_addr,
> -			   (unsigned long)desc_p->dmamac_addr +
> -			   roundup(length, ARCH_DMA_MINALIGN));
> +	flush_dcache_range(data_start, data_end);
>  
>  #if defined(CONFIG_DW_ALTDESCRIPTOR)
>  	desc_p->txrx_status |= DESC_TXSTS_TXFIRST | DESC_TXSTS_TXLAST;
> @@ -322,8 +322,7 @@ static int dw_eth_send(struct eth_device *dev, void *packet, int length)
>  #endif
>  
>  	/* Flush modified buffer descriptor */
> -	flush_dcache_range((unsigned long)desc_p,
> -			   (unsigned long)desc_p + sizeof(struct dmamacdescr));
> +	flush_dcache_range(desc_start, desc_end);
>  
>  	/* Test the wrap-around condition. */
>  	if (++desc_num >= CONFIG_TX_DESCR_NUM)
> @@ -343,11 +342,14 @@ static int dw_eth_recv(struct eth_device *dev)
>  	u32 status, desc_num = priv->rx_currdescnum;
>  	struct dmamacdescr *desc_p = &priv->rx_mac_descrtable[desc_num];
>  	int length = 0;
> +	uint32_t desc_start = (uint32_t)desc_p;
> +	uint32_t desc_end = desc_start +
> +		roundup(sizeof(*desc_p), ARCH_DMA_MINALIGN);
> +	uint32_t data_start = (uint32_t)desc_p->dmamac_addr;
> +	uint32_t data_end;
>  
>  	/* Invalidate entire buffer descriptor */
> -	invalidate_dcache_range((unsigned long)desc_p,
> -				(unsigned long)desc_p +
> -				sizeof(struct dmamacdescr));
> +	invalidate_dcache_range(desc_start, desc_end);
>  
>  	status = desc_p->txrx_status;
>  
> @@ -358,9 +360,8 @@ static int dw_eth_recv(struct eth_device *dev)
>  			 DESC_RXSTS_FRMLENSHFT;
>  
>  		/* Invalidate received data */
> -		invalidate_dcache_range((unsigned long)desc_p->dmamac_addr,
> -					(unsigned long)desc_p->dmamac_addr +
> -					roundup(length, ARCH_DMA_MINALIGN));
> +		data_end = data_start + roundup(length, ARCH_DMA_MINALIGN);
> +		invalidate_dcache_range(data_start, data_end);
>  
>  		NetReceive(desc_p->dmamac_addr, length);
>  
> @@ -371,10 +372,7 @@ static int dw_eth_recv(struct eth_device *dev)
>  		desc_p->txrx_status |= DESC_RXSTS_OWNBYDMA;
>  
>  		/* Flush only status field - others weren't changed */
> -		flush_dcache_range((unsigned long)&desc_p->txrx_status,
> -				   (unsigned long)&desc_p->txrx_status +
> -					roundup(sizeof(desc_p->txrx_status),
> -						ARCH_DMA_MINALIGN));
> +		flush_dcache_range(desc_start, desc_end);
>  
>  		/* Test the wrap-around condition. */
>  		if (++desc_num >= CONFIG_RX_DESCR_NUM)

Acked-by: Chin Liang See <clsee at altera.com>