Re: [PATCH 06/28] lib82596: move DMA allocation into the callers of i82596_probe

[Thomas Bogendoerfer]

On Wed, Aug 19, 2020 at 08:55:33AM +0200, Christoph Hellwig wrote:
> This allows us to get rid of the LIB82596_DMA_ATTR defined and prepare
> for untangling the coherent vs non-coherent DMA allocation API.
> 
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
>  drivers/net/ethernet/i825xx/lasi_82596.c | 24 ++++++++++------
>  drivers/net/ethernet/i825xx/lib82596.c   | 36 ++++++++----------------
>  drivers/net/ethernet/i825xx/sni_82596.c  | 19 +++++++++----
>  3 files changed, 40 insertions(+), 39 deletions(-)
> 
> [...]
> diff --git a/drivers/net/ethernet/i825xx/sni_82596.c b/drivers/net/ethernet/i825xx/sni_82596.c
> index 22f5887578b2bd..e80e790ffbd4d4 100644
> --- a/drivers/net/ethernet/i825xx/sni_82596.c
> +++ b/drivers/net/ethernet/i825xx/sni_82596.c
> @@ -24,8 +24,6 @@
>  
>  static const char sni_82596_string[] = "snirm_82596";
>  
> -#define LIB82596_DMA_ATTR	0
> -
>  #define DMA_WBACK(priv, addr, len)     do { } while (0)
>  #define DMA_INV(priv, addr, len)       do { } while (0)
>  #define DMA_WBACK_INV(priv, addr, len) do { } while (0)
> @@ -134,10 +132,19 @@ static int sni_82596_probe(struct platform_device *dev)
>  	lp->ca = ca_addr;
>  	lp->mpu_port = mpu_addr;
>  
> +	lp->dma = dma_alloc_coherent(dev->dev.parent, sizeof(struct i596_dma),
> +				     &lp->dma_addr, GFP_KERNEL);

this needs to use &dev->dev as device argument otherwise I get a

WARNING: CPU: 0 PID: 1 at linux/kernel/dma/mapping.c:416 dma_alloc_attrs+0x64/0x98

(coherent_dma_mask is set correctly).

dev->dev.parent was correct when going from netdevice to underlying device,
but now allocation is done via platform_device probe. I wonder why this works
for parisc.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]