Re: [PATCH 3/5] nvmem: mtk-efuse: fix different address space warnings of sparse

From: Sean Wang
Date: Wed Sep 20 2017 - 12:20:09 EST


On Mon, 2017-09-11 at 22:01 +0900, Masahiro Yamada wrote:
> Fix the following sparse warnings:
>
> drivers/nvmem/mtk-efuse.c:24:30: warning: incorrect type in initializer (different address spaces)
> drivers/nvmem/mtk-efuse.c:24:30: expected void [noderef] <asn:2>*base
> drivers/nvmem/mtk-efuse.c:24:30: got void *context
> drivers/nvmem/mtk-efuse.c:37:30: warning: incorrect type in initializer (different address spaces)
> drivers/nvmem/mtk-efuse.c:37:30: expected void [noderef] <asn:2>*base
> drivers/nvmem/mtk-efuse.c:37:30: got void *context
> drivers/nvmem/mtk-efuse.c:69:23: warning: incorrect type in assignment (different address spaces)
> drivers/nvmem/mtk-efuse.c:69:23: expected void *priv
> drivers/nvmem/mtk-efuse.c:69:23: got void [noderef] <asn:2>*[assigned] base
>
> The type of nvmem_config->priv is (void *), so sparse complains
> about assignment of the base address with (void __iomem *) type.
>
> Even if we cast it out, sparse still warns:
> warning: cast removes address space of expression
>
> Of course, we can shut up the sparse by marking __force, but a more
> correct way is to put the base address into driver private data.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>

Acked-by: Sean Wang <sean.wang@xxxxxxxxxxxx>

> ---
>
> drivers/nvmem/mtk-efuse.c | 26 +++++++++++++++++---------
> 1 file changed, 17 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/nvmem/mtk-efuse.c b/drivers/nvmem/mtk-efuse.c
> index fa7a0f6..c4058b5 100644
> --- a/drivers/nvmem/mtk-efuse.c
> +++ b/drivers/nvmem/mtk-efuse.c
> @@ -18,15 +18,19 @@
> #include <linux/nvmem-provider.h>
> #include <linux/platform_device.h>
>
> +struct mtk_efuse_priv {
> + void __iomem *base;
> +};
> +
> static int mtk_reg_read(void *context,
> unsigned int reg, void *_val, size_t bytes)
> {
> - void __iomem *base = context;
> + struct mtk_efuse_priv *priv = context;
> u32 *val = _val;
> int i = 0, words = bytes / 4;
>
> while (words--)
> - *val++ = readl(base + reg + (i++ * 4));
> + *val++ = readl(priv->base + reg + (i++ * 4));
>
> return 0;
> }
> @@ -34,12 +38,12 @@ static int mtk_reg_read(void *context,
> static int mtk_reg_write(void *context,
> unsigned int reg, void *_val, size_t bytes)
> {
> - void __iomem *base = context;
> + struct mtk_efuse_priv *priv = context;
> u32 *val = _val;
> int i = 0, words = bytes / 4;
>
> while (words--)
> - writel(*val++, base + reg + (i++ * 4));
> + writel(*val++, priv->base + reg + (i++ * 4));
>
> return 0;
> }
> @@ -50,19 +54,23 @@ static int mtk_efuse_probe(struct platform_device *pdev)
> struct resource *res;
> struct nvmem_device *nvmem;
> struct nvmem_config econfig = {};
> - void __iomem *base;
> + struct mtk_efuse_priv *priv;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
>
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> - base = devm_ioremap_resource(dev, res);
> - if (IS_ERR(base))
> - return PTR_ERR(base);
> + priv->base = devm_ioremap_resource(dev, res);
> + if (IS_ERR(priv->base))
> + return PTR_ERR(priv->base);
>
> econfig.stride = 4;
> econfig.word_size = 4;
> econfig.reg_read = mtk_reg_read;
> econfig.reg_write = mtk_reg_write;
> econfig.size = resource_size(res);
> - econfig.priv = base;
> + econfig.priv = priv;
> econfig.dev = dev;
> econfig.owner = THIS_MODULE;
> nvmem = nvmem_register(&econfig);