1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * This file contains Xilinx specific SMP code, used to start up
  4 * the second processor.
  5 *
  6 * Copyright (C) 2011-2013 Xilinx
  7 *
  8 * based on linux/arch/arm/mach-realview/platsmp.c
  9 *
 10 * Copyright (C) 2002 ARM Ltd.
 11 */
 12
 13#include <linux/export.h>
 14#include <linux/jiffies.h>
 15#include <linux/init.h>
 16#include <linux/io.h>
 17#include <asm/cacheflush.h>
 18#include <asm/smp_plat.h>
 19#include <asm/smp_scu.h>
 20#include <linux/irqchip/arm-gic.h>
 21#include "common.h"
 22
 23/*
 24 * Store number of cores in the system
 25 * Because of scu_get_core_count() must be in __init section and can't
 26 * be called from zynq_cpun_start() because it is not in __init section.
 27 */
 28static int ncores;
 29
 30int zynq_cpun_start(u32 address, int cpu)
 31{
 32	u32 trampoline_code_size = &zynq_secondary_trampoline_end -
 33						&zynq_secondary_trampoline;
 34	u32 phy_cpuid = cpu_logical_map(cpu);
 35
 36	/* MS: Expectation that SLCR are directly map and accessible */
 37	/* Not possible to jump to non aligned address */
 38	if (!(address & 3) && (!address || (address >= trampoline_code_size))) {
 39		/* Store pointer to ioremap area which points to address 0x0 */
 40		static u8 __iomem *zero;
 41		u32 trampoline_size = &zynq_secondary_trampoline_jump -
 42						&zynq_secondary_trampoline;
 43
 44		zynq_slcr_cpu_stop(phy_cpuid);
 45		if (address) {
 46			if (__pa(PAGE_OFFSET)) {
 47				zero = ioremap(0, trampoline_code_size);
 48				if (!zero) {
 49					pr_warn("BOOTUP jump vectors not accessible\n");
 50					return -1;
 51				}
 52			} else {
 53				zero = (__force u8 __iomem *)PAGE_OFFSET;
 54			}
 55
 56			/*
 57			* This is elegant way how to jump to any address
 58			* 0x0: Load address at 0x8 to r0
 59			* 0x4: Jump by mov instruction
 60			* 0x8: Jumping address
 61			*/
 62			memcpy_toio(zero, &zynq_secondary_trampoline,
 63							trampoline_size);
 64			writel(address, zero + trampoline_size);
 65
 66			flush_cache_all();
 67			outer_flush_range(0, trampoline_code_size);
 68			smp_wmb();
 69
 70			if (__pa(PAGE_OFFSET))
 71				iounmap(zero);
 72		}
 73		zynq_slcr_cpu_start(phy_cpuid);
 74
 75		return 0;
 76	}
 77
 78	pr_warn("Can't start CPU%d: Wrong starting address %x\n", cpu, address);
 79
 80	return -1;
 81}
 82EXPORT_SYMBOL(zynq_cpun_start);
 83
 84static int zynq_boot_secondary(unsigned int cpu, struct task_struct *idle)
 85{
 86	return zynq_cpun_start(__pa_symbol(secondary_startup_arm), cpu);
 87}
 88
 89/*
 90 * Initialise the CPU possible map early - this describes the CPUs
 91 * which may be present or become present in the system.
 92 */
 93static void __init zynq_smp_init_cpus(void)
 94{
 95	int i;
 96
 97	ncores = scu_get_core_count(zynq_scu_base);
 98
 99	for (i = 0; i < ncores && i < CONFIG_NR_CPUS; i++)
100		set_cpu_possible(i, true);
101}
102
103static void __init zynq_smp_prepare_cpus(unsigned int max_cpus)
104{
105	scu_enable(zynq_scu_base);
106}
107
108/**
109 * zynq_secondary_init - Initialize secondary CPU cores
110 * @cpu:	CPU that is initialized
111 *
112 * This function is in the hotplug path. Don't move it into the
113 * init section!!
114 */
115static void zynq_secondary_init(unsigned int cpu)
116{
117	zynq_core_pm_init();
118}
119
120#ifdef CONFIG_HOTPLUG_CPU
121static int zynq_cpu_kill(unsigned cpu)
122{
123	unsigned long timeout = jiffies + msecs_to_jiffies(50);
124
125	while (zynq_slcr_cpu_state_read(cpu))
126		if (time_after(jiffies, timeout))
127			return 0;
128
129	zynq_slcr_cpu_stop(cpu);
130	return 1;
131}
132
133/**
134 * zynq_cpu_die - Let a CPU core die
135 * @cpu:	Dying CPU
136 *
137 * Platform-specific code to shutdown a CPU.
138 * Called with IRQs disabled on the dying CPU.
139 */
140static void zynq_cpu_die(unsigned int cpu)
141{
142	zynq_slcr_cpu_state_write(cpu, true);
143
144	/*
145	 * there is no power-control hardware on this platform, so all
146	 * we can do is put the core into WFI; this is safe as the calling
147	 * code will have already disabled interrupts
148	 */
149	for (;;)
150		cpu_do_idle();
151}
152#endif
153
154const struct smp_operations zynq_smp_ops __initconst = {
155	.smp_init_cpus		= zynq_smp_init_cpus,
156	.smp_prepare_cpus	= zynq_smp_prepare_cpus,
157	.smp_boot_secondary	= zynq_boot_secondary,
158	.smp_secondary_init	= zynq_secondary_init,
159#ifdef CONFIG_HOTPLUG_CPU
160	.cpu_die		= zynq_cpu_die,
161	.cpu_kill		= zynq_cpu_kill,
162#endif
163};