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kernel/linux-imx6_3.14.28/arch/arm/mach-zynq/platsmp.c 3.36 KB
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  /*
   * This file contains Xilinx specific SMP code, used to start up
   * the second processor.
   *
   * Copyright (C) 2011-2013 Xilinx
   *
   * based on linux/arch/arm/mach-realview/platsmp.c
   *
   * Copyright (C) 2002 ARM Ltd.
   *
   * This software is licensed under the terms of the GNU General Public
   * License version 2, as published by the Free Software Foundation, and
   * may be copied, distributed, and modified under those terms.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   */
  
  #include <linux/export.h>
  #include <linux/jiffies.h>
  #include <linux/init.h>
  #include <linux/io.h>
  #include <asm/cacheflush.h>
  #include <asm/smp_scu.h>
  #include <linux/irqchip/arm-gic.h>
  #include "common.h"
  
  /*
   * Store number of cores in the system
   * Because of scu_get_core_count() must be in __init section and can't
   * be called from zynq_cpun_start() because it is not in __init section.
   */
  static int ncores;
  
  int zynq_cpun_start(u32 address, int cpu)
  {
  	u32 trampoline_code_size = &zynq_secondary_trampoline_end -
  						&zynq_secondary_trampoline;
  
  	/* MS: Expectation that SLCR are directly map and accessible */
  	/* Not possible to jump to non aligned address */
  	if (!(address & 3) && (!address || (address >= trampoline_code_size))) {
  		/* Store pointer to ioremap area which points to address 0x0 */
  		static u8 __iomem *zero;
  		u32 trampoline_size = &zynq_secondary_trampoline_jump -
  						&zynq_secondary_trampoline;
  
  		zynq_slcr_cpu_stop(cpu);
  		if (address) {
  			if (__pa(PAGE_OFFSET)) {
  				zero = ioremap(0, trampoline_code_size);
  				if (!zero) {
  					pr_warn("BOOTUP jump vectors not accessible
  ");
  					return -1;
  				}
  			} else {
  				zero = (__force u8 __iomem *)PAGE_OFFSET;
  			}
  
  			/*
  			* This is elegant way how to jump to any address
  			* 0x0: Load address at 0x8 to r0
  			* 0x4: Jump by mov instruction
  			* 0x8: Jumping address
  			*/
  			memcpy((__force void *)zero, &zynq_secondary_trampoline,
  							trampoline_size);
  			writel(address, zero + trampoline_size);
  
  			flush_cache_all();
  			outer_flush_range(0, trampoline_code_size);
  			smp_wmb();
  
  			if (__pa(PAGE_OFFSET))
  				iounmap(zero);
  		}
  		zynq_slcr_cpu_start(cpu);
  
  		return 0;
  	}
  
  	pr_warn("Can't start CPU%d: Wrong starting address %x
  ", cpu, address);
  
  	return -1;
  }
  EXPORT_SYMBOL(zynq_cpun_start);
  
  static int zynq_boot_secondary(unsigned int cpu,
  						struct task_struct *idle)
  {
  	return zynq_cpun_start(virt_to_phys(zynq_secondary_startup), cpu);
  }
  
  /*
   * Initialise the CPU possible map early - this describes the CPUs
   * which may be present or become present in the system.
   */
  static void __init zynq_smp_init_cpus(void)
  {
  	int i;
  
  	ncores = scu_get_core_count(zynq_scu_base);
  
  	for (i = 0; i < ncores && i < CONFIG_NR_CPUS; i++)
  		set_cpu_possible(i, true);
  }
  
  static void __init zynq_smp_prepare_cpus(unsigned int max_cpus)
  {
  	scu_enable(zynq_scu_base);
  }
  
  #ifdef CONFIG_HOTPLUG_CPU
  static int zynq_cpu_kill(unsigned cpu)
  {
  	zynq_slcr_cpu_stop(cpu);
  	return 1;
  }
  #endif
  
  struct smp_operations zynq_smp_ops __initdata = {
  	.smp_init_cpus		= zynq_smp_init_cpus,
  	.smp_prepare_cpus	= zynq_smp_prepare_cpus,
  	.smp_boot_secondary	= zynq_boot_secondary,
  #ifdef CONFIG_HOTPLUG_CPU
  	.cpu_die		= zynq_platform_cpu_die,
  	.cpu_kill		= zynq_cpu_kill,
  #endif
  };