Re: resource sanity fails on ioremap

[Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>]

On Thu, Feb 04, 2016 at 08:05:00PM -0800, Jarkko Sakkinen wrote:

> 4.4 does not use devm_ioremap_resource(). That is why this is
> confusing. If that was the kernel from my master branch, then this
> would make sense.

It makes sense, the MSFT resource is created by the kernel when it
parses the ACPI tables.

devm_ioremap_resource creates a child resource of the above owned by
the driver.

Eg, a PCI example:

$ cat /proc/iomem
    d0000000-d0003fff : 0000:06:00.0
          d0000000-d0003fff : r8169

0000:06:00.0 is created by parsing the BAR, it always exists,
equivalent to the MSFT resource

r8169 is created when the driver attaches to it, and serves to lock
the memory range from other drivers.

tpm_crb works the same.

ioremap complains if a mapping crosses any resource boundary, not
just driver created resources.

Jason

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