Re: [PATCHv5] staging: vme_user: provide DMA functionality

[Alessio Igor Bogani]

Hi,

On 19 October 2015 at 00:04, Martyn Welch <martyn@xxxxxxxxxxxx> wrote:
> On 18/10/15 18:53, Dmitry Kalinkin wrote:
[...]
>> Other drives meaning vme_pio, I don't see any others. All this time
>> we are discussing how many GE PIO boards one can plug into a crate
>> with or without vme_user. Most of people have zero of them.
>> Also, VME DMA API has no users in kernel, we are just adding one now.
>
>
> Unfortunately not all users of Linux upstream or even publicise their
> drivers. This is especially true of some industries where VME gets used. The
> number of VME windows is limited, so having a user space shim either hog or
> limit the number of resources available either in kernel space or user space
> is not an optimal solution.

We aren't an industry but we are exactly in that position: we have a
bunch of unpublished kernel driver for VME boards almost all built on
top of the customized old vmelinux.org stack.
We already tried to port a driver to current stack but we stuck on the
static resource management approach in particular for limited VME
windows (when the customization of the old stack was made for handle
VME windows dynamically).

Ciao,
Alessio
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