Re: [OpenOCD-user] Openocd SWD flash with sysfs or gpiod is too long on Radxa Pi / AMLogic S905Y2

[Paul F. <fer...@gm...>]

Hi Maximin,

On Thu, Jul 28, 2022 at 02:38:53PM +0200, Maximin COSTE wrote:
> It is my understanding that the BCM2835gpio driver for OpenOCD uses
> specific directs RAM access to achieve the speed I mesured in my
> usage (5-6 seconds).

Strictly speaking, it's not RAM but memory-mapped GPIO peripheral
addresses but the overally notion is correct, if you're using
interface bcm2835gpio then OpenOCD manipulates the GPIO controller
directly, without kernel involved.

> It looks like nothing comparable is available
> for AMLogic S905Y2/ Radxa Pi ?  I might have no searched deep
> enough, or in the right place.  If nothing is available, how do you
> see this ? Should it be straight forward to implement ? Can I get at
> least the same performances I had with the BCM2835gpio driver ?

It should be reasonably straightforward if you have the SoC docs,
yes. See src/jtag/drivers/bcm2835gpio.c and
src/jtag/drivers/imx_gpio.c for the reference. It's about the same as
you would manipulate GPIOs on an MCU without using additional
libraries, just directly writing and reading from the corresponding
peripheral's registers.

HTH
-- 
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