Re: [PATCH V2] mtd: bcm47xxsflash: use ioremap_cache() instead of KSEG0ADDR()

[Brian Norris <computersforpeace@gmail.com>]

+ others

On Fri, Feb 26, 2016 at 11:50:28AM +0100, Rafał Miłecki wrote:
> From: Brian Norris <computersforpeace@gmail.com>
> 
> Using KSEG0ADDR makes code highly MIPS dependent and not portable.
> Thanks to the fix a68f376 ("MIPS: io.h: Define `ioremap_cache'") we can
> use ioremap_cache which is generic and supported on MIPS as well now.
> 
> KSEG0ADDR was translating 0x1c000000 into 0x9c000000. With ioremap_cache
> we use MIPS's __ioremap (and then remap_area_pages). This results in
> different address (e.g. 0xc0080000) but it still should be cached as
> expected and it was successfully tested with BCM47186B0.
> 
> Other than that drivers/bcma/driver_chipcommon_sflash.c nicely setups a
> struct resource for access window, but we wren't using it. Use it now
> and drop duplicated info.
> 
> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
> Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
> ---
> V2:
> 1) Use ioremap_cache as we already have commit a68f376 in l2-mtd
> 2) Add iounmap to the error path
> 3) Update commit message

Hmm, I'm a bit out of the loop on some things here, but it looks like
ioremap_cache() is going away. See kernel/memremap.c:

/* temporary while we convert existing ioremap_cache users to memremap */
__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)

Are we supposed to move to using memremap() here? (If so,
devm_memremap() can help us.)

Brian


>  drivers/bcma/driver_chipcommon_sflash.c     |  1 -
>  drivers/mtd/devices/bcm47xxsflash.c         | 29 ++++++++++++++++++++++++-----
>  drivers/mtd/devices/bcm47xxsflash.h         |  3 ++-
>  include/linux/bcma/bcma_driver_chipcommon.h |  1 -
>  4 files changed, 26 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/bcma/driver_chipcommon_sflash.c b/drivers/bcma/driver_chipcommon_sflash.c
> index 7e11ef4..5534cbc 100644
> --- a/drivers/bcma/driver_chipcommon_sflash.c
> +++ b/drivers/bcma/driver_chipcommon_sflash.c
> @@ -145,7 +145,6 @@ int bcma_sflash_init(struct bcma_drv_cc *cc)
>  		return -ENOTSUPP;
>  	}
>  
> -	sflash->window = BCMA_SOC_FLASH2;
>  	sflash->blocksize = e->blocksize;
>  	sflash->numblocks = e->numblocks;
>  	sflash->size = sflash->blocksize * sflash->numblocks;
> diff --git a/drivers/mtd/devices/bcm47xxsflash.c b/drivers/mtd/devices/bcm47xxsflash.c
> index 347bb83..1c65c15 100644
> --- a/drivers/mtd/devices/bcm47xxsflash.c
> +++ b/drivers/mtd/devices/bcm47xxsflash.c
> @@ -2,6 +2,7 @@
>  #include <linux/module.h>
>  #include <linux/slab.h>
>  #include <linux/delay.h>
> +#include <linux/ioport.h>
>  #include <linux/mtd/mtd.h>
>  #include <linux/platform_device.h>
>  #include <linux/bcma/bcma.h>
> @@ -109,8 +110,7 @@ static int bcm47xxsflash_read(struct mtd_info *mtd, loff_t from, size_t len,
>  	if ((from + len) > mtd->size)
>  		return -EINVAL;
>  
> -	memcpy_fromio(buf, (void __iomem *)KSEG0ADDR(b47s->window + from),
> -		      len);
> +	memcpy_fromio(buf, b47s->window + from, len);
>  	*retlen = len;
>  
>  	return len;
> @@ -275,15 +275,33 @@ static void bcm47xxsflash_bcma_cc_write(struct bcm47xxsflash *b47s, u16 offset,
>  
>  static int bcm47xxsflash_bcma_probe(struct platform_device *pdev)
>  {
> -	struct bcma_sflash *sflash = dev_get_platdata(&pdev->dev);
> +	struct device *dev = &pdev->dev;
> +	struct bcma_sflash *sflash = dev_get_platdata(dev);
>  	struct bcm47xxsflash *b47s;
> +	struct resource *res;
>  	int err;
>  
> -	b47s = devm_kzalloc(&pdev->dev, sizeof(*b47s), GFP_KERNEL);
> +	b47s = devm_kzalloc(dev, sizeof(*b47s), GFP_KERNEL);
>  	if (!b47s)
>  		return -ENOMEM;
>  	sflash->priv = b47s;
>  
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res) {
> +		dev_err(dev, "invalid resource\n");
> +		return -EINVAL;
> +	}
> +	if (!devm_request_mem_region(dev, res->start, resource_size(res),
> +				     res->name)) {
> +		dev_err(dev, "can't request region for resource %pR\n", res);
> +		return -EBUSY;
> +	}
> +	b47s->window = ioremap_cache(res->start, resource_size(res));
> +	if (!b47s->window) {
> +		dev_err(dev, "ioremap failed for resource %pR\n", res);
> +		return -ENOMEM;
> +	}
> +
>  	b47s->bcma_cc = container_of(sflash, struct bcma_drv_cc, sflash);
>  	b47s->cc_read = bcm47xxsflash_bcma_cc_read;
>  	b47s->cc_write = bcm47xxsflash_bcma_cc_write;
> @@ -297,7 +315,6 @@ static int bcm47xxsflash_bcma_probe(struct platform_device *pdev)
>  		break;
>  	}
>  
> -	b47s->window = sflash->window;
>  	b47s->blocksize = sflash->blocksize;
>  	b47s->numblocks = sflash->numblocks;
>  	b47s->size = sflash->size;
> @@ -306,6 +323,7 @@ static int bcm47xxsflash_bcma_probe(struct platform_device *pdev)
>  	err = mtd_device_parse_register(&b47s->mtd, probes, NULL, NULL, 0);
>  	if (err) {
>  		pr_err("Failed to register MTD device: %d\n", err);
> +		iounmap(b47s->window);
>  		return err;
>  	}
>  
> @@ -321,6 +339,7 @@ static int bcm47xxsflash_bcma_remove(struct platform_device *pdev)
>  	struct bcm47xxsflash *b47s = sflash->priv;
>  
>  	mtd_device_unregister(&b47s->mtd);
> +	iounmap(b47s->window);
>  
>  	return 0;
>  }
> diff --git a/drivers/mtd/devices/bcm47xxsflash.h b/drivers/mtd/devices/bcm47xxsflash.h
> index fe93daf..1564b62 100644
> --- a/drivers/mtd/devices/bcm47xxsflash.h
> +++ b/drivers/mtd/devices/bcm47xxsflash.h
> @@ -65,7 +65,8 @@ struct bcm47xxsflash {
>  
>  	enum bcm47xxsflash_type type;
>  
> -	u32 window;
> +	void __iomem *window;
> +
>  	u32 blocksize;
>  	u16 numblocks;
>  	u32 size;
> diff --git a/include/linux/bcma/bcma_driver_chipcommon.h b/include/linux/bcma/bcma_driver_chipcommon.h
> index db51a6f..03e6fea 100644
> --- a/include/linux/bcma/bcma_driver_chipcommon.h
> +++ b/include/linux/bcma/bcma_driver_chipcommon.h
> @@ -583,7 +583,6 @@ struct mtd_info;
>  
>  struct bcma_sflash {
>  	bool present;
> -	u32 window;
>  	u32 blocksize;
>  	u16 numblocks;
>  	u32 size;
> -- 
> 1.8.4.5
>