xref: /openbmc/u-boot/arch/arm/mach-tegra/tegra20/cpu.c (revision dd1033e4)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2010-2012, NVIDIA CORPORATION.  All rights reserved.
4  */
5 
6 #include <common.h>
7 #include <asm/io.h>
8 #include <asm/arch/tegra.h>
9 #include <asm/arch-tegra/pmc.h>
10 #include "../cpu.h"
11 
12 static void enable_cpu_power_rail(void)
13 {
14 	struct pmc_ctlr *pmc = (struct pmc_ctlr *)NV_PA_PMC_BASE;
15 	u32 reg;
16 
17 	reg = readl(&pmc->pmc_cntrl);
18 	reg |= CPUPWRREQ_OE;
19 	writel(reg, &pmc->pmc_cntrl);
20 
21 	/*
22 	 * The TI PMU65861C needs a 3.75ms delay between enabling
23 	 * the power rail and enabling the CPU clock.  This delay
24 	 * between SM1EN and SM1 is for switching time + the ramp
25 	 * up of the voltage to the CPU (VDD_CPU from PMU).
26 	 */
27 	udelay(3750);
28 }
29 
30 void start_cpu(u32 reset_vector)
31 {
32 	/* Enable VDD_CPU */
33 	enable_cpu_power_rail();
34 
35 	/* Hold the CPUs in reset */
36 	reset_A9_cpu(1);
37 
38 	/* Disable the CPU clock */
39 	enable_cpu_clock(0);
40 
41 	/* Enable CoreSight */
42 	clock_enable_coresight(1);
43 
44 	/*
45 	 * Set the entry point for CPU execution from reset,
46 	 *  if it's a non-zero value.
47 	 */
48 	if (reset_vector)
49 		writel(reset_vector, EXCEP_VECTOR_CPU_RESET_VECTOR);
50 
51 	/* Enable the CPU clock */
52 	enable_cpu_clock(1);
53 
54 	/* If the CPU doesn't already have power, power it up */
55 	powerup_cpu();
56 
57 	/* Take the CPU out of reset */
58 	reset_A9_cpu(0);
59 }
60