Re: PCIE: Program pcie device private registers

Re: PCIE: Program pcie device private registers

[Yinghai Lu]

On Thu, Feb 27, 2014 at 1:12 AM, shiv prakash Agarwal
<chhotu.shiv@gmail.com> wrote:
> Hi All,
>
> We can program config space registers of a pcie device using setpci but how
> can we program private registers of a pcie device?

What do you mean private registers?

Are those registers in MMIO range that is set through pci BAR?

Thanks

Yinghai

Re: PCIE: Program pcie device private registers

[Pratyush Anand]

On Thu, Feb 27, 2014 at 05:12:38PM +0800, shiv prakash Agarwal wrote:
>    Hi All,
> 
>     
> 
>    One query:
> 
>     
> 
>    We can program config space registers of a pcie device using setpci but
>    how can we program private registers of a pcie device?

You mean application specific registers?
These registers will not be accessible through any generic user space program.

If you want to access them for debug purposes then you can provide
support in your driver.

Regards
Pratyush
> 
>    Can it be done through PCIE interface or something else?
> 
>     
> 
>    With best,
> 
>    Jay

Re: PCIE: Program pcie device private registers

[Bjorn Helgaas]

On Mon, Mar 3, 2014 at 8:59 PM, Pratyush Anand <pratyush.anand@st.com> wrote:
> On Thu, Feb 27, 2014 at 05:12:38PM +0800, shiv prakash Agarwal wrote:
>>    Hi All,
>>
>>
>>
>>    One query:
>>
>>
>>
>>    We can program config space registers of a pcie device using setpci but
>>    how can we program private registers of a pcie device?
>
> You mean application specific registers?
> These registers will not be accessible through any generic user space program.
>
> If you want to access them for debug purposes then you can provide
> support in your driver.

If the registers are in config space, you can use setpci, even if they
are non-architected registers specific to the device.

If they are in MMIO space, you can use lspci to learn where the BARs
are mapped, and then use something like rdwrmem
(http://cmp.felk.cvut.cz/~pisa/linux/rdwrmem.c) to access the
registers.

If they are in I/O port space, you can again use lspci to learn where
they are mapped, and then use ioperm()/iopl()/inb()/outb()/etc.

Bjorn

Re: PCIE: Program pcie device private registers

[Alex Williamson]

On Tue, 2014-03-04 at 10:45 -0700, Bjorn Helgaas wrote:
> On Mon, Mar 3, 2014 at 8:59 PM, Pratyush Anand <pratyush.anand@st.com> wrote:
> > On Thu, Feb 27, 2014 at 05:12:38PM +0800, shiv prakash Agarwal wrote:
> >>    Hi All,
> >>
> >>
> >>
> >>    One query:
> >>
> >>
> >>
> >>    We can program config space registers of a pcie device using setpci but
> >>    how can we program private registers of a pcie device?
> >
> > You mean application specific registers?
> > These registers will not be accessible through any generic user space program.
> >
> > If you want to access them for debug purposes then you can provide
> > support in your driver.
> 
> If the registers are in config space, you can use setpci, even if they
> are non-architected registers specific to the device.
> 
> If they are in MMIO space, you can use lspci to learn where the BARs
> are mapped, and then use something like rdwrmem
> (http://cmp.felk.cvut.cz/~pisa/linux/rdwrmem.c) to access the
> registers.
> 
> If they are in I/O port space, you can again use lspci to learn where
> they are mapped, and then use ioperm()/iopl()/inb()/outb()/etc.

The pci-sysfs resource# files are probably an easier alternative.  MMIO
regions can be mmap'd and I/O port regions support direct read/write.
Thanks,

Alex

PCIE: Program pcie device private registers

[shiv prakash Agarwal]

Hi All,

One query:

We can program config space registers of a pcie device using setpci
but how can we program private registers of a pcie device?

Can it be done through PCIE interface or something else?