lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Fri, 12 May 2017 12:13:41 +0000
From:   Chris Brandt <>
To:     Geert Uytterhoeven <>,
        Linus Walleij <>
CC:     jmondi <>,
        Andy Shevchenko <>,
        Jacopo Mondi <>,
        Geert Uytterhoeven <>,
        Laurent Pinchart <>,
        Rob Herring <>,
        "Mark Rutland" <>,
        Russell King - ARM Linux <>,
        Linux-Renesas <>,
        "" <>,
        devicetree <>,
        "" <>
Subject: RE: [PATCH v5 01/10] pinctrl: generic: Add bi-directional and

Hi Geert and Linus,

On Friday, May 12, 2017, Geert Uytterhoeven wrote:
> Jacopo, Chris: Would two bits per pin/function (none, input, output,
> bidir)
> be sufficient?
> That makes one u16 per pin. So roughtly 12 ports x 16 pins => 384 bytes.
> Plus code to handle it. After all not that bad...

OK...I give up!
If that's what it takes to get it, I'm fine.

NOTE, your math is a little off, the issue is that depending on the
function that you use, you might need to do extra settings, so you'd
have to have a lookup table for every pin & function.
Each pin can have 1 of 8 functions (which is good because a 'byte' has
8 bits).

 12 ports x 16 pins => 384 bytes  (this table would just be for checking if bi-dir is needed)
 12 ports x 16 pins => 384 bytes  (this table would just be for checking if input is needed)
 12 ports x 16 pins => 384 bytes  (this table would just be for checking if input is needed)
                     1,152 bytes

But then...there are package variations so you need another entire
table for those parts.
   1,152 bytes x 2 = 2,304 bytes

However, if these tables are constants, they will reside in flash for the
XIP_KERNEL systems, so that's OK.

#What we should really do is just make a look-up table (tables) for the
'special' ones. But, we can have that discussion in a different thread.

One final note:

There is still a need for "input-enable" and "output-enable" for the timer
pins. Because, when you choose the pin to be connected to the MTU2 timer,
the pin can be used as either input-capture/output-compare/PWM and that's
the user's choice. So that's probably a valid usage of the generic pin
properties for configuration.

Sorry Jacopo, but we'll need another round of patches.
It sounds like for sure the bi-direction needs to get ripped back out.


Powered by blists - more mailing lists