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@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.