/*
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* Rockchip rk3288 resume code
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*
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* This code is intended to be linked into the embedded resume binary
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* for the rk3288 SoC
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*
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* Copyright (c) 2014 Google, Inc
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include "rk3288_resume.h"
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#include "rk3288_resume_embedded.h"
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#define INIT_CPSR (PSR_I_BIT | PSR_F_BIT | SVC_MODE)
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static __noreturn void rk3288_resume(void);
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/* Parameters of early board initialization in SPL */
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struct rk3288_resume_params rk3288_resume_params
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__attribute__((section(".resume_params"))) = {
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.resume_loc = rk3288_resume,
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};
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/**
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* rk3288_resume_c - Main C entry point for rk3288 at resume time
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*
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* This function is called by rk3288_resume() and does the brunt of
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* any resume processing. After it's done it will call the kernel's
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* cpu_resume() function (which it finds through its params structure).
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*
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* At the time this function is called:
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* - We know we're on CPU0.
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* - Interrupts are disabled.
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* - We've got a stack.
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* - The cache is turned off, so all addresses are physical.
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* - SDRAM hasn't been restored yet (if it was off).
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*
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* WARNING: This code, the stack and the params structure are all sitting in
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* PMU SRAM. If you try to write to that memory using an 8-bit access (or even
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* 16-bit) you'll get an imprecise data abort and it will be very hard to debug.
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* Keep everything in here as 32-bit wide and aligned. YOU'VE BEEN WARNED.
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*/
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static void __noreturn rk3288_resume_c(void)
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{
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#ifdef CONFIG_ARM_ERRATA_818325
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u32 val = 0;
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asm("mrc p15, 0, %0, c15, c0, 1" : "=r" (val));
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val |= BIT(12);
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asm("mcr p15, 0, %0, c15, c0, 1" : : "r" (val));
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#endif
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if (rk3288_resume_params.l2ctlr_f)
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asm("mcr p15, 1, %0, c9, c0, 2" : :
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"r" (rk3288_resume_params.l2ctlr));
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if (rk3288_resume_params.ddr_resume_f)
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rk3288_ddr_resume_early(&rk3288_resume_params.ddr_save_data);
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rk3288_resume_params.cpu_resume();
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}
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/**
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* rk3288_resume - First entry point for rk3288 at resume time
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*
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* A pointer to this function is stored in rk3288_resume_params. The
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* kernel uses the pointer in that structure to find this function and
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* to put its (physical) address in a location that it will get jumped
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* to at resume time.
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*
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* There is no stack at the time this function is called, so this
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* function is in charge of setting it up. We get to a function with
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* a normal stack pointer ASAP.
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*/
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static void __naked __noreturn rk3288_resume(void)
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{
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/* Make sure we're on CPU0, no IRQs and get a stack setup */
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asm volatile (
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"msr cpsr_cxf, %0\n"
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/* Only cpu0 continues to run, the others halt here */
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"mrc p15, 0, r1, c0, c0, 5\n"
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"and r1, r1, #0xf\n"
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"cmp r1, #0\n"
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"beq cpu0run\n"
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"secondary_loop:\n"
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"wfe\n"
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"b secondary_loop\n"
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"cpu0run:\n"
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"mov sp, %1\n"
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:
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: "i" (INIT_CPSR), "r" (&__stack_start)
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: "cc", "r1", "sp");
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/* Now get into a normal function that can use a stack */
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rk3288_resume_c();
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}
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