freebsd-dev/sys/arm/qualcomm/qcom_cpu_kpssv2.h
Adrian Chadd d3514c2942 ipq401x: add MP core start-up path for the CPU regulator/clock gate used
This code implements the "kpssv2" flavour of CPU regulator/clock gating
in Linux.  It's used by at least the ipq4018/4019 to power on and off
CPU cores.

This is based on the Linux implementation - the register definitions
and values are from Linux and I've reverse engineered the sequencing
requirements.

The MP bring-up is:

* set cold boot address via an SCM call - this is the address used
  by the bootloader/TZ firmware to jump to when the CPUs boot

* power down the LDO feeding the CPU core and wait for it to settle

* program in the right set of LDO and power tree configuration for
  the CPU regulator to power up the core.  Unfortunately these are
  magic numbers that I've not found documented anywhere.

* (I think) power up the shared L2 cache connect if it isn't.

* Clamp the power into the core down; put the core into reset

* Unclamp the power rail; release reset; and then set the core to boot.

The MP core will then boot the bootloader/TZ firmware and then
will wait until an incoming interrupt kicks it to start @ mpentry.

Tested:

* IPQ4019, 4 CPUs

Release APs
CPU(3) applied BP hardening: not necessary
CPU(1) applied BP hardening: not necessary
CPU(2) applied BP hardening: not necessary

Reviewed by: andrew, manu, imp
Differential Revision: https://reviews.freebsd.org/D32723
2021-11-04 09:02:36 -07:00

36 lines
1.6 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2021 Adrian Chadd <adrian@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef __QCOM_CPU_KPSSV2_H__
#define __QCOM_CPU_KPSSV2_H__
extern boolean_t qcom_cpu_kpssv2_regulator_start(u_int id, phandle_t node);
#endif /* __QCOM_CPU_KPSSV2_H__ */