From mboxrd@z Thu Jan 1 00:00:00 1970 From: slash.tmp@free.fr (Mason) Date: Tue, 22 Sep 2015 18:08:36 +0200 Subject: Steps to submit a new arch/arm port In-Reply-To: <20150921161341.GP21084@n2100.arm.linux.org.uk> References: <56001B78.2090001@free.fr> <20150921161341.GP21084@n2100.arm.linux.org.uk> Message-ID: <56017D04.5010909@free.fr> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 21/09/2015 18:13, Russell King - ARM Linux wrote: > On Mon, Sep 21, 2015 at 05:00:08PM +0200, Mason wrote: >> 1) Linux kernel runs in non-secure world. The port used to tweak >> L2 cache configuration via custom SMC calls to the OS running in >> secure world. I've removed that for now. >> Is there a standard solution these days? > > While some configuration can be done by the boot loader (and it's > preferable for that to happen) not all of it can be. In particular, > the kernel _must_ have the ability to enable and disable the L2 > cache, and the kernel must not be called with the L2 cache left > enabled by the boot loader. > > That requires that the L2 control register is writable in some way > from the non-secure world. There is no agreed-upon method to do that? What about Samsung's arch/arm/include/asm/firmware.h ? Is there an easy way to determine how many arch/arm platforms are running Linux in non-secure mode? (And thus need to interact with "firmware" or trustzone OS for things like L2 cache handling, and secondary core boot-up.) Regards.