[U-Boot] [PATCH v2 00/13] ARMv7: add PSCI support to u-boot

[Marc Zyngier]

Hi Albert,

On 13/02/14 10:11, Albert ARIBAUD wrote:
> Hi Marc,
> 
> On Sat,  7 Dec 2013 11:19:05 +0000, Marc Zyngier <marc.zyngier at arm.com>
> wrote:
> 
>> PSCI is an ARM standard that provides a generic interface that
>> supervisory software can use to manage power in the following
>> situations:
>> - Core idle management
>> - CPU hotplug
>> - big.LITTLE migration models
>> - System shutdown and reset
>>
>> It basically allows the kernel to offload these tasks to the firmware,
>> and rely on common kernel side code.
>>
>> More importantly, it gives a way to ensure that CPUs enter the kernel
>> at the appropriate exception level (ie HYP mode, to allow the use of
>> the virtualization extensions), even across events like CPUs being
>> powered off/on or suspended.
>>
>> The main idea here is to turn some of the existing u-boot code into a
>> separate section that can live in secure RAM (or a reserved page of
>> memory), containing a secure monitor that will implement the PSCI
>> operations. This code will still be alive when u-boot is long gone,
>> hence the need for a piece of memory that will not be touched by the
>> OS.
>>
>> This patch series contains 4 parts:
>> - the first four patches are just bug fixes
>> - the next three refactor the HYP/non-secure code to allow relocation
>>   in secure memory
>> - the next three contain the generic PSCI code and DT infrastructure
>> - the last three implement the CPU_ON method of the Allwinner A20 (aka sun7i).
>>
>> I realize the A20 u-boot code is not upstream yet (BTW is anyone
>> actively working on that?), but hopefully that should give a good idea
>> of how things are structured so far. The patches are against the sunxi
>> u-boot tree as of today, and the first 10 patches will directly apply
>> to mainline u-boot.
>>
>> As for using this code, it goes like this:
>> sun7i# ext2load mmc 0:1 0x40008000 zImage ; ext2load mmc 0:1 0x60000000 sun7i-a20-cubietruck.dtb
>> 2270120 bytes read in 117 ms (18.5 MiB/s)
>> 9138 bytes read in 3 ms (2.9 MiB/s)
>> sun7i# fdt addr 0x60000000 ; fdt resize ; fdt set ethernet0 mac-address "[5a fe b0 07 b0 07]"
>> sun7i# setenv bootargs console=ttyS0,115200 earlyprintk ip=dhcp root=/dev/nfs nfsroot=/backup/a20_root,tcp
>> sun7i# bootz 0x40008000 - 0x60000000
>>
>> The kernel now boots in HYP mode, finds its secondary CPU without any
>> SMP code present in the kernel, and runs KVM out of the box.
>> Hopefully, the Xen/ARM guys can do the same fairly easily.
>>
>> This code has also been tested on a VExpress TC2, running KVM with all
>> 5 CPUs, in order to make sure there was no obvious regression.
>>
>> I'm wildly cross-posting this patch series, including to lists I'm not
>> subscribed to. Please keep me on Cc for any comment you may have.
>>
>> Cheers,
>>
>>         M.
> 
> There are comments re 01/13 an 07/13. Should I expect a V3 on the
> U-Boot ML?

Yes. As I said yesterday, I plan to address the comments pretty quickly
(during the weekend anyway), and repost a new version on the same
mailing lists.

Thanks,

	M.
-- 
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