Re: [RFC PATCH v3 05/16] ARM: edma: add AM33XX crossbar event support

[Sekhar Nori <nsekhar-l0cyMroinI0@public.gmane.org>]

On 10/18/2012 6:56 PM, Matt Porter wrote:
> Adds support for the per-EDMA channel event mux. This is required
> for any peripherals using DMA crossbar mapped events.
> 
> Signed-off-by: Matt Porter <mporter-l0cyMroinI0@public.gmane.org>
> ---
>  arch/arm/common/edma.c             |   63 +++++++++++++++++++++++++++++++++++-
>  include/linux/platform_data/edma.h |    1 +
>  2 files changed, 63 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/common/edma.c b/arch/arm/common/edma.c
> index 6d2a590..b761b7a 100644
> --- a/arch/arm/common/edma.c
> +++ b/arch/arm/common/edma.c
> @@ -1425,6 +1425,53 @@ static int edma_of_read_u32_to_s16_array(const struct device_node *np,
>  	return 0;
>  }
>  
> +static int edma_xbar_event_map(struct device *dev,
> +			       struct device_node *node,
> +			       struct edma_soc_info *pdata, int len)
> +{
> +	int ret = 0;
> +	int i;
> +	struct resource res;
> +	void *xbar;
> +	s16 (*xbar_chans)[2];
> +	u32 shift, offset, mux;
> +
> +	xbar_chans = devm_kzalloc(dev,
> +				  len/sizeof(s16) + 2*sizeof(s16),
> +				  GFP_KERNEL);
> +	if (!xbar_chans)
> +		return -ENOMEM;
> +
> +	ret = of_address_to_resource(node, 1, &res);
> +	if (IS_ERR_VALUE(ret))
> +		return -EIO;
> +
> +	xbar = devm_ioremap(dev, res.start, resource_size(&res));
> +	if (!xbar)
> +		return -EIO;

-ENOMEM is more appropiate for ioremap failures.

> +
> +	ret = edma_of_read_u32_to_s16_array(node,
> +					    "ti,edma-xbar-event-map",
> +					    (s16 *)xbar_chans,
> +					    len/sizeof(u32));
> +	if (IS_ERR_VALUE(ret))
> +		return -EIO;
> +
> +	for (i = 0; xbar_chans[i][0] != -1; i++) {
> +		shift = (xbar_chans[i][1] % 4) * 8;
> +		offset = xbar_chans[i][1] >> 2;
> +		offset <<= 2;
> +		mux = __raw_readl((void *)((u32)xbar + offset));

Dont use __raw* variants of io accessors. There will be ordering issues
on ARMv7.

> +		mux &= (~(0xff << shift));
> +		mux |= (xbar_chans[i][0] << shift);

Unnecessary parens above.

> +		__raw_writel(mux, (void *)((u32)xbar + offset));
> +	}
> +
> +	pdata->xbar_chans = xbar_chans;
> +
> +	return 0;
> +}
> +
>  static int edma_of_parse_dt(struct device *dev,
>  			    struct device_node *node,
>  			    struct edma_soc_info *pdata)
> @@ -1453,7 +1500,6 @@ static int edma_of_parse_dt(struct device *dev,
>  	pdata->n_slot = value;
>  
>  	pdata->n_cc = 1;
> -	/* This is unused */

The comment should have not been part of 4/16?

Thanks,
Sekhar