Re: [PATCH] firmware: qcom_scm: fix error for incompatible pointer

Marc Gonzalez
2019-07-22T08:38:59Z

Adding people who have worked on drivers/firmware/qcom_scm.c or DMA

On 19/07/2019 15:43, Minwoo Im wrote:

> The following error can happen when trying to build it:
>
> ```
> drivers/firmware/qcom_scm.c: In function ‘qcom_scm_assign_mem’:
> drivers/firmware/qcom_scm.c:460:47: error: passing argument 3 of ‘dma_alloc_coherent’ from incompatible pointer type [-Werror=incompatible-pointer-types]
> ptr = dma_alloc_coherent(__scm->dev, ptr_sz, &ptr_phys, GFP_KERNEL);
> ^
> In file included from drivers/firmware/qcom_scm.c:12:0:
> ./include/linux/dma-mapping.h:636:21: note: expected ‘dma_addr_t * {aka long long unsigned int *}’ but argument is of type ‘phys_addr_t * {aka unsigned int *}’
> static inline void *dma_alloc_coherent(struct device *dev, size_t size,
> ^~~~~~~~~~~~~~~~~~
> ```
>
> We just can cast phys_addr_t to dma_addr_t here.

IME, casting is rarely a proper solution.

> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> index 2ddc118dba1b..7f6c841fa200 100644
> --- a/drivers/firmware/qcom_scm.c
> +++ b/drivers/firmware/qcom_scm.c
> @@ -457,7 +457,8 @@ int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz,
> ptr_sz = ALIGN(src_sz, SZ_64) + ALIGN(mem_to_map_sz, SZ_64) +
> ALIGN(dest_sz, SZ_64);
>
> - ptr = dma_alloc_coherent(__scm->dev, ptr_sz, &ptr_phys, GFP_KERNEL);
> + ptr = dma_alloc_coherent(__scm->dev, ptr_sz, (dma_addr_t *) &ptr_phys,
> + GFP_KERNEL);
> if (!ptr)
> return -ENOMEM;
>