Re: [PATCH] tty: serial: bcm63xx: allow building on ARM64

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, Dec 08, 2020 at 11:45:33AM +0100, Geert Uytterhoeven wrote:
> Hi Greg,
> 
> On Wed, Nov 25, 2020 at 9:53 AM Greg Kroah-Hartman
> <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> > On Wed, Nov 25, 2020 at 09:38:50AM +0100, Rafał Miłecki wrote:
> > > On 25.11.2020 09:23, Greg Kroah-Hartman wrote:
> > > > On Wed, Nov 25, 2020 at 09:13:52AM +0100, Rafał Miłecki wrote:
> > > > > From: Rafał Miłecki <rafal@xxxxxxxxxx>
> > > > >
> > > > > Hardware supported by bcm63xx is also used by BCM4908 SoCs family that
> > > > > is ARM64.
> > > > >
> > > > > Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
> > > > > ---
> > > > >   drivers/tty/serial/Kconfig | 3 ++-
> > > > >   1 file changed, 2 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> > > > > index 28f22e58639c..6907c5b17a0e 100644
> > > > > --- a/drivers/tty/serial/Kconfig
> > > > > +++ b/drivers/tty/serial/Kconfig
> > > > > @@ -1133,7 +1133,8 @@ config SERIAL_TIMBERDALE
> > > > >   config SERIAL_BCM63XX
> > > > >           tristate "Broadcom BCM63xx/BCM33xx UART support"
> > > > >           select SERIAL_CORE
> > > > > - depends on MIPS || ARM || COMPILE_TEST
> > > > > + depends on MIPS || ARM || ARM64 || COMPILE_TEST
> 
> Why not s/ARM64/ARCH_BCM4908/?
> 
> > > >
> > > > Why do we have an arch dependancy at all now?
> > >
> > > From my experience "depends" is often used to limit symbol visibility to
> > > applicable platforms only. I don't think Broadcom has any x86, risc, etc.
> > > platforms so it's useless there.
> > >
> > > As for testing driver compilation on unused arch-s I thought that's what
> > > COMPILE_TEST is for.
> > >
> > > Am I wrong there? I'm afraid we don't have clear Documentation on that.
> > > Please kindly point me to some info if I'm wrong.
> >
> > If COMPILE_TEST is working for this driver, then trying to restrict it
> > to a specific arch is usually pointless and the arch dependency can be
> > removed, keeping patches like this from having to be made over time to
> > add it to new arches :)
> >
> > > > > + default ARCH_BCM4908
> > > >
> > > > Really?  I thought we were getting rid of these "ARCH_platform_type" of
> 
> No we are not.

Ok, I keep getting mixed signals here.

> > > > things.  That's what a defconfig file is for, right?
> 
> FWIW, the arm64 defconfig file enables about everything, for all arm64
> platforms.

Then why are there ARCH_platforms for arm64 systems?

> > > I had to miss something, last time I checked Linus called defconfigs a
> > > garbage and wanted to get rid of them:
> > > https://lwn.net/Articles/391372/
> > >
> > > There are also no platform defconfigs in arch/arm64/ at all. Should I
> > > handle it with arch/arm64/Kconfig.platforms and "select SERIAL_BCM63XX"?
> >
> > I thought we were trying to get rid of arm64 "platforms" as well.  My
> > point being, why is this needed at all?
> 
> To prevent asking the user about a driver that is completely useless for
> the system(s) the user is compiling a kernel for.

How do you "know" that given the huge number of different ip blocks in
SoC systems these days?

> Do you want to let distros compile all arm/arm64-only SoC drivers for x86, too?

Sure, many have crossed over over the years and shown up there.

But distro config owners are smarter than that, give them some credit :)

thanks,

greg k-h



[Index of Archives]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux PPP]     [Linux FS]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Linmodem]     [Device Mapper]     [Linux Kernel for ARM]

  Powered by Linux