[U-Boot] [PATCH v1 0/2] Allow platform specific service handling on PSCI

[Ang, Chee Hong <chee.hong.ang@intel.com>]

On Fri, 2019-03-08 at 13:09 -0500, Tom Rini wrote:
> On Tue, Feb 12, 2019 at 12:27:01AM -0800, chee.hong.ang at intel.com
> wrote:
> 
> > 
> > From: "Ang, Chee Hong" <chee.hong.ang@intel.com>
> > 
> > Currently u-boot only support standard PSCI functions for power
> > management
> > and lack of convenient method to allow the users to extend the PSCI
> > functions
> > to support platform specific services. Most of the u-boot users
> > still rely
> > on ATF (ARM Trusted Firmware) to handle the standard power
> > management and
> > platform specific PSCI services.
> > The purpose of this patchsets is to allow u-boot users to support
> > their
> > own platform specific secure SMC/PSCI services without making any
> > SMC calls to ATF. This will benefit the users who need to use u-
> > boot as the
> > only bootloader and secure service provider without relying on ATF.
> > 
> > Below is a simple code example for adding your own PSCI functions:
> > 
> > #include <common.h>
> > #include <errno.h>
> > #include <asm/io.h>
> > #include <asm/psci.h>
> > #include <asm/secure.h>
> > 
> > #define PSCI_SMC64_FUNC_ID1	0xC2000001
> > #define PSCI_SMC64_FUNC_ID2	0xC2000002
> > 
> > static void __secure psci_plat_specific_func1(unsigned long
> > function_id)
> > {
> > 	/* Your code for handling the SMC/PSCI platform specific
> > service 1 */
> > }
> > 
> > static void __secure psci_plat_specific_func2(unsigned long
> > function_id)
> > {
> > 	/* Your code for handling the SMC/PSCI platform specific
> > service 2 */
> > }
> > 
> > DECLARE_SECURE_SVC(plat_specific_func1, PSCI_SMC64_FUNC_ID1,
> > 		   psci_plat_specific_func1);
> > DECLARE_SECURE_SVC(plat_specific_func2, PSCI_SMC64_FUNC_ID2,
> > 		   psci_plat_specific_func2);
> > 
> > Ang, Chee Hong (1):
> >   ARMv8: Disable fwcall when PSCI is enabled
> > 
> > Chee Hong Ang (1):
> >   ARMv8: Allow SiP service extensions on top of PSCI code
> Conceptually, I suppose this is a logical step.  In specifics, would
> we
> want to make this functionality opt-in, or no, that doesn't make
> sense?
> 
Allowing user to add platform specific service is part of SMC/PSCI
specification as specifed in ARM document (Table 2-1):
http://infocenter.arm.com/help/topic/com.arm.doc.den0028b/ARM_DEN0028B_
SMC_Calling_Convention.pdf

So I think this functionality should be part of the standard PSCI/SMC
implementation. Currently u-boot only support standard PSCI call which
is:
----------------------------------------------
| 0x84000000-0x8400001F  | PSCI 32-bit calls |
| 0xC4000000-0xC400001F  | PSCI 64-bit calls |
----------------------------------------------

My implementation do not affect or alter the behavior of any existing
standard PSCI calls.

Users can simply add their own platform specific services by using the
service call range as below:
----------------------------------------------------
| 0xC2000000-0xC200FFFF | SMC64: SiP Service Calls |
| 0xC3000000-0xC300FFFF | SMC64: OEM Service Calls |
----------------------------------------------------

For complete service call ranges please refer to Table 6-2 in the ARM
document.