Re: [PATCH net-next v3 3/3] net: ipa: Grab IMEM slice base/size from DTS

[Alex Elder <elder@ieee.org>]

On 2/17/26 7:30 AM, Konrad Dybcio wrote:
> From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> 
> This is a detail that differ per chip, and not per IPA version (and
> there are cases of the same IPA versions being implemented across very
> very very different SoCs).
> 
> This region isn't actually used by the driver, but we most definitely
> want to iommu-map it, so that IPA can poke at the data within.
> 
> Reviewed-by: Alex Elder <elder@riscstar.com>
> Acked-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> Reviewed-by: Simon Horman <horms@kernel.org>
> Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

I know I already provided Reviewed-by, but I have two
minor comments.  (You can keep my tag even if you don't
incorporate what I suggest below.)

> ---
>   drivers/net/ipa/ipa_data.h |  4 ++++
>   drivers/net/ipa/ipa_mem.c  | 21 ++++++++++++++++++++-
>   2 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ipa/ipa_data.h b/drivers/net/ipa/ipa_data.h
> index 2fd03f0799b2..5fe164981083 100644
> --- a/drivers/net/ipa/ipa_data.h
> +++ b/drivers/net/ipa/ipa_data.h
> @@ -185,8 +185,12 @@ struct ipa_resource_data {
>   struct ipa_mem_data {
>   	u32 local_count;
>   	const struct ipa_mem *local;
> +
> +	/* DEPRECATED (now passed via DT) fallback data,
> +	 * varies per chip and not per IPA version */
>   	u32 imem_addr;
>   	u32 imem_size;

Both the address and size are deprecated, and although you add
white space, I feel like you could be more explicit about saying
both are deprecated.  For example, maybe more like this?

     /* These values are now passed via DT, but to support
      * older systems we must allow this to be specified here.
      */
     u32 imem_addr;	/* DEPRECATED */
     u32 imem_size;	/* DEPRECATED */

> +
>   	u32 smem_size;
>   };
>   
> diff --git a/drivers/net/ipa/ipa_mem.c b/drivers/net/ipa/ipa_mem.c
> index 835a3c9c1fd4..583aea625709 100644
> --- a/drivers/net/ipa/ipa_mem.c
> +++ b/drivers/net/ipa/ipa_mem.c
> @@ -7,6 +7,7 @@
>   #include <linux/dma-mapping.h>
>   #include <linux/io.h>
>   #include <linux/iommu.h>
> +#include <linux/of_address.h>
>   #include <linux/platform_device.h>
>   #include <linux/types.h>
>   
> @@ -617,7 +618,9 @@ static void ipa_smem_exit(struct ipa *ipa)
>   int ipa_mem_init(struct ipa *ipa, struct platform_device *pdev,
>   		 const struct ipa_mem_data *mem_data)
>   {
> +	struct device_node *ipa_slice_np;
>   	struct device *dev = &pdev->dev;
> +	u32 imem_base, imem_size;
>   	struct resource *res;
>   	int ret;
>   
> @@ -656,7 +659,23 @@ int ipa_mem_init(struct ipa *ipa, struct platform_device *pdev,
>   	ipa->mem_addr = res->start;
>   	ipa->mem_size = resource_size(res);
>   
> -	ret = ipa_imem_init(ipa, mem_data->imem_addr, mem_data->imem_size);
> +	ipa_slice_np = of_parse_phandle(dev->of_node, "sram", 0);
> +	if (ipa_slice_np) {
> +		ret = of_address_to_resource(ipa_slice_np, 0, res);
> +		of_node_put(ipa_slice_np);
> +		if (ret)
> +			return ret;
> +
> +		imem_base = res->start;
> +		imem_size = resource_size(res);
> +	} else {
> +		/* Backwards compatibility for DTs lacking
> +		 * an explicit reference */

I think netdev style says the end-of-comment should go on
the line below.

					-Alex

> +		imem_base = mem_data->imem_addr;
> +		imem_size = mem_data->imem_size;
> +	}
> +
> +	ret = ipa_imem_init(ipa, imem_base, imem_size);
>   	if (ret)
>   		goto err_unmap;
>   
>