Subject: [PATCH v2 1/2] dmaengine: hdmac: factorise memset descriptor allocation

From: [email-masked] (Nicolas Ferre)
Date: Thu, 22 Oct 2015 12:13:07 +0200

Le 22/10/2015 11:40, Maxime Ripard a ?crit :
> The memset and scatter gathered memset are going to use some common logic
> to create their descriptors.
> 
> Move that logic into a function of its own so that we can share it with the
> future memset_sg callback.
> 
> Signed-off-by: Maxime Ripard <[email-masked]>
> ---
>  drivers/dma/at_hdmac.c      | 97 ++++++++++++++++++++++++++-------------------
>  drivers/dma/at_hdmac_regs.h |  2 +-
>  2 files changed, 58 insertions(+), 41 deletions(-)
> 
> diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
> index 58d406230d89..cad18f3660ae 100644
> --- a/drivers/dma/at_hdmac.c
> +++ b/drivers/dma/at_hdmac.c
> @@ -458,10 +458,10 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
>  		dma_cookie_complete(txd);
>  
>  	/* If the transfer was a memset, free our temporary buffer */
> -	if (desc->memset) {
> +	if (desc->memset_buffer) {
>  		dma_pool_free(atdma->memset_pool, desc->memset_vaddr,
>  			      desc->memset_paddr);
> -		desc->memset = false;
> +		desc->memset_buffer = false;
>  	}
>  
>  	/* move children to free_list */
> @@ -881,6 +881,46 @@ err_desc_get:
>  	return NULL;
>  }
>  
> +static struct at_desc *atc_create_memset_desc(struct dma_chan *chan,
> +					      dma_addr_t psrc,
> +					      dma_addr_t pdst,
> +					      size_t len)
> +{
> +	struct at_dma_chan *atchan = to_at_dma_chan(chan);
> +	struct at_desc *desc;
> +	size_t xfer_count;
> +
> +	u32 ctrla = ATC_SRC_WIDTH(2) | ATC_DST_WIDTH(2);
> +	u32 ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN |
> +		ATC_SRC_ADDR_MODE_FIXED |
> +		ATC_DST_ADDR_MODE_INCR |
> +		ATC_FC_MEM2MEM;
> +
> +	xfer_count = len >> 2;
> +	if (xfer_count > ATC_BTSIZE_MAX) {
> +		dev_err(chan2dev(chan), "%s: buffer is too big\n",
> +			__func__);
> +		return NULL;
> +	}
> +
> +	desc = atc_desc_get(atchan);
> +	if (!desc) {
> +		dev_err(chan2dev(chan), "%s: can't get a descriptor\n",
> +			__func__);
> +		return NULL;
> +	}
> +
> +	desc->lli.saddr = psrc;
> +	desc->lli.daddr = pdst;
> +	desc->lli.ctrla = ctrla | xfer_count;
> +	desc->lli.ctrlb = ctrlb;
> +
> +	desc->txd.cookie = 0;
> +	desc->len = len;
> +
> +	return desc;
> +}
> +
>  /**
>   * atc_prep_dma_memset - prepare a memcpy operation
>   * @chan: the channel to prepare operation on
> @@ -893,12 +933,10 @@ static struct dma_async_tx_descriptor *
>  atc_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
>  		    size_t len, unsigned long flags)
>  {
> -	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
>  	struct at_dma		*atdma = to_at_dma(chan->device);
> -	struct at_desc		*desc = NULL;
> -	size_t			xfer_count;
> -	u32			ctrla;
> -	u32			ctrlb;
> +	struct at_desc		*desc;
> +	void __iomem		*vaddr;
> +	dma_addr_t		paddr;
>  
>  	dev_vdbg(chan2dev(chan), "%s: d0x%x v0x%x l0x%zx f0x%lx\n", __func__,
>  		dest, value, len, flags);
> @@ -914,46 +952,26 @@ atc_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
>  		return NULL;
>  	}
>  
> -	xfer_count = len >> 2;
> -	if (xfer_count > ATC_BTSIZE_MAX) {
> -		dev_err(chan2dev(chan), "%s: buffer is too big\n",
> +	vaddr = dma_pool_alloc(atdma->memset_pool, GFP_ATOMIC, &paddr);
> +	if (!vaddr) {
> +		dev_err(chan2dev(chan), "%s: couldn't allocate buffer\n",
>  			__func__);
>  		return NULL;
>  	}
> +	*(u32*)vaddr = value;
>  
> -	ctrlb =   ATC_DEFAULT_CTRLB | ATC_IEN
> -		| ATC_SRC_ADDR_MODE_FIXED
> -		| ATC_DST_ADDR_MODE_INCR
> -		| ATC_FC_MEM2MEM;
> -
> -	ctrla = ATC_SRC_WIDTH(2) |
> -		ATC_DST_WIDTH(2);
> -
> -	desc = atc_desc_get(atchan);
> +	desc = atc_create_memset_desc(chan, paddr, dest, len);
>  	if (!desc) {
> -		dev_err(chan2dev(chan), "%s: can't get a descriptor\n",
> +		dev_err(chan2dev(chan), "%s: couldn't get a descriptor\n",
>  			__func__);

Nitpicking: as you already have a dev_err() for each error possible in
the called function, you wouldn't need more log hereunder...

otherwise, I'm okay:
Acked-by: Nicolas Ferre <[email-masked]>

> -		return NULL;
> +		goto err_free_buffer;
>  	}
>  
> -	desc->memset_vaddr = dma_pool_alloc(atdma->memset_pool, GFP_ATOMIC,
> -					    &desc->memset_paddr);
> -	if (!desc->memset_vaddr) {
> -		dev_err(chan2dev(chan), "%s: couldn't allocate buffer\n",
> -			__func__);
> -		goto err_put_desc;
> -	}
> -
> -	*desc->memset_vaddr = value;
> -	desc->memset = true;
> -
> -	desc->lli.saddr = desc->memset_paddr;
> -	desc->lli.daddr = dest;
> -	desc->lli.ctrla = ctrla | xfer_count;
> -	desc->lli.ctrlb = ctrlb;
> +	desc->memset_paddr = paddr;
> +	desc->memset_vaddr = vaddr;
> +	desc->memset_buffer = true;
>  
>  	desc->txd.cookie = -EBUSY;
> -	desc->len = len;
>  	desc->total_len = len;
>  
>  	/* set end-of-link on the descriptor */
> @@ -963,12 +981,11 @@ atc_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
>  
>  	return &desc->txd;
>  
> -err_put_desc:
> -	atc_desc_put(atchan, desc);
> +err_free_buffer:
> +	dma_pool_free(atdma->memset_pool, vaddr, paddr);
>  	return NULL;
>  }
>  
> -
>  /**
>   * atc_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction
>   * @chan: DMA channel
> diff --git a/drivers/dma/at_hdmac_regs.h b/drivers/dma/at_hdmac_regs.h
> index c3bebbe899ac..d1cfc8c876f9 100644
> --- a/drivers/dma/at_hdmac_regs.h
> +++ b/drivers/dma/at_hdmac_regs.h
> @@ -202,7 +202,7 @@ struct at_desc {
>  	size_t				src_hole;
>  
>  	/* Memset temporary buffer */
> -	bool				memset;
> +	bool				memset_buffer;
>  	dma_addr_t			memset_paddr;
>  	int				*memset_vaddr;
>  };
> 

-- 
Nicolas Ferre