xref: /openbmc/u-boot/arch/arm/mach-tegra/tegra20/cpu.c (revision baefb63a)
1 /*
2  * Copyright (c) 2010-2012, NVIDIA CORPORATION.  All rights reserved.
3  *
4  * SPDX-License-Identifier:	GPL-2.0
5  */
6 
7 #include <common.h>
8 #include <asm/io.h>
9 #include <asm/arch/tegra.h>
10 #include <asm/arch-tegra/pmc.h>
11 #include "../cpu.h"
12 
13 static void enable_cpu_power_rail(void)
14 {
15 	struct pmc_ctlr *pmc = (struct pmc_ctlr *)NV_PA_PMC_BASE;
16 	u32 reg;
17 
18 	reg = readl(&pmc->pmc_cntrl);
19 	reg |= CPUPWRREQ_OE;
20 	writel(reg, &pmc->pmc_cntrl);
21 
22 	/*
23 	 * The TI PMU65861C needs a 3.75ms delay between enabling
24 	 * the power rail and enabling the CPU clock.  This delay
25 	 * between SM1EN and SM1 is for switching time + the ramp
26 	 * up of the voltage to the CPU (VDD_CPU from PMU).
27 	 */
28 	udelay(3750);
29 }
30 
31 void start_cpu(u32 reset_vector)
32 {
33 	/* Enable VDD_CPU */
34 	enable_cpu_power_rail();
35 
36 	/* Hold the CPUs in reset */
37 	reset_A9_cpu(1);
38 
39 	/* Disable the CPU clock */
40 	enable_cpu_clock(0);
41 
42 	/* Enable CoreSight */
43 	clock_enable_coresight(1);
44 
45 	/*
46 	 * Set the entry point for CPU execution from reset,
47 	 *  if it's a non-zero value.
48 	 */
49 	if (reset_vector)
50 		writel(reset_vector, EXCEP_VECTOR_CPU_RESET_VECTOR);
51 
52 	/* Enable the CPU clock */
53 	enable_cpu_clock(1);
54 
55 	/* If the CPU doesn't already have power, power it up */
56 	powerup_cpu();
57 
58 	/* Take the CPU out of reset */
59 	reset_A9_cpu(0);
60 }
61