[RFC PATCH] irq/mbigen:Fix the problem of IO remap for duplicated physical address in mbigen driver
majun (F)
majun258 at huawei.com
Tue Feb 2 02:25:53 PST 2016
Hi Mark:
在 2016/2/1 21:25, Mark Rutland 写道:
> On Mon, Feb 01, 2016 at 09:06:38PM +0800, majun (F) wrote:
>>
>>
>> 在 2016/2/1 19:57, Mark Rutland 写道:
>>> On Mon, Feb 01, 2016 at 07:44:54PM +0800, MaJun wrote:
>>>> From: Ma Jun <majun258 at huawei.com>
>>>>
>>>> For mbigen module, there is a special case that more than one mbigen
>>>> device nodes use the same reg definition in DTS when these devices
>>>> exist in the same mbigen hardware module.
>>>>
>>>> mbigen_dev1:intc_dev1 {
>>>> ...
>>>> reg = <0x0 0xc0080000 0x0 0x10000>;
>>>> ...
>>>> };
>>>>
>>>> mbigen_dev2:intc_dev2 {
>>>> ...
>>>> reg = <0x0 0xc0080000 0x0 0x10000>;
>>>> ...
>>>> };
>>>
>>> This doesn't sound right. If they exist in the same place, and have the
>>> same reg, they _are_ the same device.
>>>
>>> You'll need to explain this better.
>>>
>>
>> For a mbigen hardware module which connecte with several devices,
>> because these devices has different device ID,
>> I need to define a device node for each device in DTS file.
>>
>> mbigen
>> |
>> ------------------
>> | | |
>> dev1 dev2 dev3
>>
>> Because of register layout,the registers related with these devices
>> are put together, I can't split them clearly.
>> So, I only make these devices which connect with
>> same mbigen hardware module usethe same address.
>
> This sounds like we've either mis-described the mbigen in the binding,
> or we're mis-describing the relationship with the devices.
>
Sorry, I didn't express myself clearly.
For example, a mbigen hardware module can support several peripheral devices
with different device ID.
|-----------------------|-
| mbigen |
|-----------------------|-
| | |
dev1 dev2 dev3
To simplify the mbigen drvier,
I didn't use the whole mbigen module as a mbgien device, but use
the register collections(vector, trigger type,status etc.) corresponding
to a peripheral device as a mbigen device.
So, mbigen device is a logical conception or logical device.
Now, a mbigen hardware module contains several logical mbigen device.
-------------------------------
|mgn_dev1 mgn_dev2 mgn_dev3 |
|-----------------------------|
| | |
dev1 dev2 dev3
So,mgn_dev1, mgn_dev2 and mgn_dev3 exist in same mbigen hardware module,
and,they use the same reg address region,that is adress of mbigen hardware module.
For this case, I think the question is can we map an reg address
region more than one time?
Thanks!
> It should not be necessary to describe the same set of registers
> repeatedly.
>
>>>> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>>> - mgn_chip->base = devm_ioremap_resource(&pdev->dev, res);
>>>> + mgn_chip->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
>>>
>>> These two behaving differently doesn't seem correct either...
>>
>> The problem is caused by memory region check fail because of
>> duplicated address in devm_ioremap_resource().
>
> The check is sensible. Using devm_ioremap rather than
> devm_ioremap_resource to avoid the check is not the correct solution.
>
>> For mbigen special case, there is no necessary to do this check.
>
> I'm not sure I fully agree.
>
> Regardless, this is not the right solution; it is fragile at best.
>
> Thanks,
> Mark.
>
> .
>
More information about the linux-arm-kernel
mailing list