lkml.org 
[lkml]   [2017]   [Mar]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH 1/1] drivers/misc: Add Intel System ID driver
    On Wed, Mar 1, 2017 at 11:42 AM, Loh, Tien Hock <tien.hock.loh@intel.com> wrote:
    > On Rab, 2017-03-01 at 10:01 +0100, Arnd Bergmann wrote:
    >> On Wed, Mar 1, 2017 at 8:23 AM, Loh, Tien Hock <tien.hock.loh@intel.c
    >> Another option would be to fold the timestamp into the revision
    >> attribute,
    >> but whether that is a reasonable place for it would in turn depend on
    >> what the timestamp signifies.
    >>
    >> Can you explain what the timestamp is used for? Does it identify the
    >> time that the hardware revision was made, the time that a software
    >> was built which was loaded into it, or something else?
    >> What kind of user space application would need this information?
    >
    > I just checked, and it seems like we can't put this into soc subsystem.
    > In FPGA, we now can do partial reconfiguration, which "reconfigures"
    > the hardware to have an updated sysid and timestamp value, and the base
    > address of the Intel System ID may also be changed. This would require
    > the driver to be a module that will be removed, probed again. The soc
    > subsystem doesn't seem to be a suitable place to add this driver.

    Ah, I had not realized this is for fpga_manager.

    Why not put the attributes into /sys/class/fpga_manager/*/ then
    along with the other attributes that exist there? That way, we have
    an interface that works for all users of drivers/fpga/

    > A note on the timestamp, in the old days this is used to check that the
    > BSP is using the correct FPGA hardware. I believe in Linux we should do
    > the same in the driver, and if it not, the driver should print a
    > warning. The timestamp's print is not exactly needed. I'll add the
    > feature into the driver in the next patch.

    Ok.

    Arnd

    \
     
     \ /
      Last update: 2017-03-01 12:44    [W:9.130 / U:0.112 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site