On 05/11/2018 11:25 AM, Ley Foon Tan wrote:
On Fri, May 11, 2018 at 4:44 PM, Marek Vasut marex@denx.de wrote:
On 05/11/2018 07:45 AM, Ley Foon Tan wrote:
On Thu, May 10, 2018 at 6:09 PM, Marek Vasut marex@denx.de wrote:
On 05/10/2018 10:45 AM, Ley Foon Tan wrote:
On Tue, May 8, 2018 at 5:21 PM, Marek Vasut marex@denx.de wrote:
On 05/08/2018 08:49 AM, Ley Foon Tan wrote: > On Thu, Apr 19, 2018 at 10:53 AM, Marek Vasut marex@denx.de wrote: >> On 04/19/2018 11:50 AM, Ley Foon Tan wrote: >>> Add mailbox support for Stratix SoC >>> >>> Signed-off-by: Ley Foon Tan ley.foon.tan@intel.com >>> Signed-off-by: Chin Liang See chin.liang.see@intel.com >>> ---
[...]
>>> +static __always_inline int mbox_polling_resp(u32 rout) >>> +{ >>> + static const struct socfpga_mailbox *mbox_base = >>> + (void *)SOCFPGA_MAILBOX_ADDRESS; >>> + u32 rin; >>> + unsigned long i = ~0; >>> + >>> + while (i) { >>> + rin = readl(&mbox_base->rin); >>> + if (rout != rin) >>> + return 0; >> >> This looks like include/wait_bit.h reimplementation > The reason we use this method instead of using wait_bit because this > function will use in Secure Monitor Call (SMC) call as well. > When run in secure section, timer is not available. So, we can't use > wait_for_bit.
Can't you just do timer_init() then ?
We can't use timer in secure region. This SMC code is resident in onchip memory (secure region) while Linux is running. So, timer might be used by Linux.
So pieces of U-Boot remain in memory and get called by Linux, right ?
Normal U-boot (in DDR) is destroyed after Linux is running, only SMC code Onchip memory will remain. The existing U-boot have support this SMC feature, platform just need to configure the CONFIG_ARMV8_SECURE_BASE for the secure section. Of course, we need to enable CONFIG_ARMV8_PSCI too.
So piece of U-Boot then becomes the part which handles PSCI calls from Linux, do I understand it correctly ?
Yes, and we put this piece of code in onchip memory in our platform so it doesn't corrupted by Linux.
You can see detail in http://git.denx.de/?p=u-boot.git;a=blob;f=arch/arm/cpu/armv8/u-boot.lds All code related to PSCI/SMC will put in secure section.
I see, nice, I didnt know about that. Thanks