On Mon, 21 Jul 2014 21:59:51 +0100 Ian Campbell ijc@hellion.org.uk wrote:
On Mon, 2014-07-21 at 22:39 +0200, Jeroen Hofstee wrote:
Hello Ian,
On 21-07-14 22:07, Ian Campbell wrote:
On Fri, 2014-07-18 at 20:47 +0200, Jeroen Hofstee wrote:
Hello Siarhei,
On 18-07-14 19:09, Siarhei Siamashka wrote:
This is needed to have feature parity with the normal boot mode, where the L2EN bit in the CP15 Auxiliary Control Register is set by the BROM code right from the start.
If this is not done, the Linux system ends up booted with the L2 cache disabled.
I don't know a single about the sunxi, but shouldn't linux be patched instead. The commit message seems to indicate it is not an u-boot issue.
The ACTLR may not be writeable from NS mode so it has to be setup in the bootloader before dropping to NS mode.
mmm, I guess there is something wrong with the boot sequence if the kernel itself can't access raw hw.
Do you know what ARM Secure and Non-Secure worlds are?
The kernel expects to be launched in NS mode and simply cannot access this register. This is a feature not a bug.
Just curious. Is there a modern consensus about how this all is supposed to be done nowadays?
The last time I read anything about this subject was the following longish and already old discussion thread (which has probably already lost relevance): http://lists.linaro.org/pipermail/boot-architecture/2011-August/000060.html
Since the Allwinner BROM does not forcefully drop us to the non-secure mode, we have the absolute freedom of choice and may implement any policy.