# Re: \[PATCH v2 3/9\] ntb: intel: Constify ioreadX() iomem argument (as in generic implementation)

- From: Dave Jiang \<dave.jiang@intel.com\>
- Date: 2020-01-08 20:29:14 
- List: netdev
- Page: https://ratatoskr.run/netdev/2020/01/5824935
- Thread: https://ratatoskr.run/linuxppc-dev/2020/01/5824889/t.md

```text


On 1/8/20 1:05 PM, Krzysztof Kozlowski wrote:
> The ioreadX() helpers have inconsistent interface.  On some architectures
> void *__iomem address argument is a pointer to const, on some not.
>
> Implementations of ioreadX() do not modify the memory under the address
> so they can be converted to a "const" version for const-safety and
> consistency among architectures.
>
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Acked-by: Dave Jiang <dave.jiang@intel.com>

>
> ---
>
> Changes since v1:
> 1. Add Geert's review.
> ---
>   drivers/ntb/hw/intel/ntb_hw_gen1.c  | 2 +-
>   drivers/ntb/hw/intel/ntb_hw_gen3.h  | 2 +-
>   drivers/ntb/hw/intel/ntb_hw_intel.h | 2 +-
>   3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/ntb/hw/intel/ntb_hw_gen1.c b/drivers/ntb/hw/intel/ntb_hw_gen1.c
> index bb57ec239029..9202502a9787 100644
> --- a/drivers/ntb/hw/intel/ntb_hw_gen1.c
> +++ b/drivers/ntb/hw/intel/ntb_hw_gen1.c
> @@ -1202,7 +1202,7 @@ int intel_ntb_peer_spad_write(struct ntb_dev *ntb, int pidx, int sidx,
>   			       ndev->peer_reg->spad);
>   }
>   
> -static u64 xeon_db_ioread(void __iomem *mmio)
> +static u64 xeon_db_ioread(const void __iomem *mmio)
>   {
>   	return (u64)ioread16(mmio);
>   }
> diff --git a/drivers/ntb/hw/intel/ntb_hw_gen3.h b/drivers/ntb/hw/intel/ntb_hw_gen3.h
> index 75fb86ca27bb..d1455f24ec99 100644
> --- a/drivers/ntb/hw/intel/ntb_hw_gen3.h
> +++ b/drivers/ntb/hw/intel/ntb_hw_gen3.h
> @@ -91,7 +91,7 @@
>   #define GEN3_DB_TOTAL_SHIFT		33
>   #define GEN3_SPAD_COUNT			16
>   
> -static inline u64 gen3_db_ioread(void __iomem *mmio)
> +static inline u64 gen3_db_ioread(const void __iomem *mmio)
>   {
>   	return ioread64(mmio);
>   }
> diff --git a/drivers/ntb/hw/intel/ntb_hw_intel.h b/drivers/ntb/hw/intel/ntb_hw_intel.h
> index e071e28bca3f..3c0a5a2da241 100644
> --- a/drivers/ntb/hw/intel/ntb_hw_intel.h
> +++ b/drivers/ntb/hw/intel/ntb_hw_intel.h
> @@ -102,7 +102,7 @@ struct intel_ntb_dev;
>   struct intel_ntb_reg {
>   	int (*poll_link)(struct intel_ntb_dev *ndev);
>   	int (*link_is_up)(struct intel_ntb_dev *ndev);
> -	u64 (*db_ioread)(void __iomem *mmio);
> +	u64 (*db_ioread)(const void __iomem *mmio);
>   	void (*db_iowrite)(u64 db_bits, void __iomem *mmio);
>   	unsigned long			ntb_ctl;
>   	resource_size_t			db_size;
>
```