Re: [PATCH RFC] usb: gadget: Add xilinx axi usb2 device support

[Michal Simek]

On 02/21/2014 04:42 PM, Felipe Balbi wrote:
> Hi,
> 
> On Fri, Feb 21, 2014 at 02:41:03PM +0100, Michal Simek wrote:
>>>>> +	/* Map the registers */
>>>>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>>>> +	udc->base_address = devm_ioremap_nocache(&pdev->dev, res->start,
>>>>> +						 resource_size(res));
>>>>
>>>> use devm_ioremap_resource() instead.
>>>
>>> Also, res might be NULL. You should check that before dereferencing it.
>>
>> yes it is necessary for both cases with devm_ioremap_nocache
>> or with devm_ioremap_resource.
> 
> read the source Luke:
> 
> | void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res)
> | {
> | 	resource_size_t size;
> | 	const char *name;
> | 	void __iomem *dest_ptr;
> | 
> | 	BUG_ON(!dev);
> | 
> | 	if (!res || resource_type(res) != IORESOURCE_MEM) {
>             ^^^^
> 	    already done for you
> 
> | 		dev_err(dev, "invalid resource\n");
> | 		return ERR_PTR(-EINVAL);
> | 	}
> | 
> | 	size = resource_size(res);
> | 	name = res->name ?: dev_name(dev);
> | 
> | 	if (!devm_request_mem_region(dev, res->start, size, name)) {
> | 		dev_err(dev, "can't request region for resource %pR\n", res);
> | 		return ERR_PTR(-EBUSY);
> | 	}
> | 
> | 	if (res->flags & IORESOURCE_CACHEABLE)
> | 		dest_ptr = devm_ioremap(dev, res->start, size);
> | 	else
> | 		dest_ptr = devm_ioremap_nocache(dev, res->start, size);

I have read it just not sure if IORESOURCE_CACHEABLE is setup by default
or not.
If yes, then you have to setup res->flags in your driver and have to
check it.

Thanks,
Michal

-- 
Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel - Microblaze cpu - http://www.monstr.eu/fdt/
Maintainer of Linux kernel - Xilinx Zynq ARM architecture
Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform

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