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kernel/linux-imx6_3.14.28/arch/arm/mach-imx/platsmp.c 2.98 KB
6b13f685e   김민수   BSP 최초 추가
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  /*
   * Copyright 2011-2014 Freescale Semiconductor, Inc.
   * Copyright 2011 Linaro Ltd.
   *
   * The code contained herein is licensed under the GNU General Public
   * License. You may obtain a copy of the GNU General Public License
   * Version 2 or later at the following locations:
   *
   * http://www.opensource.org/licenses/gpl-license.html
   * http://www.gnu.org/copyleft/gpl.html
   */
  
  #include <linux/init.h>
  #include <linux/smp.h>
  #include <asm/cacheflush.h>
  #include <asm/page.h>
  #include <asm/smp_scu.h>
  #include <asm/mach/map.h>
  
  #include "common.h"
  #include "hardware.h"
  
  #define SCU_STANDBY_ENABLE	(1 << 5)
  
  u32 g_diag_reg;
  void __iomem *imx_scu_base;
  
  static struct map_desc scu_io_desc __initdata = {
  	/* .virtual and .pfn are run-time assigned */
  	.length		= SZ_4K,
  	.type		= MT_DEVICE,
  };
  
  void __init imx_scu_map_io(void)
  {
  	unsigned long base;
  
  	/* Get SCU base */
  	asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (base));
  
  	scu_io_desc.virtual = IMX_IO_P2V(base);
  	scu_io_desc.pfn = __phys_to_pfn(base);
  	iotable_init(&scu_io_desc, 1);
  
  	imx_scu_base = IMX_IO_ADDRESS(base);
  }
  
  void imx_scu_standby_enable(void)
  {
  	u32 val = readl_relaxed(imx_scu_base);
  
  	val |= SCU_STANDBY_ENABLE;
  	writel_relaxed(val, imx_scu_base);
  }
  
  static int __cpuinit imx_boot_secondary(unsigned int cpu, struct task_struct *idle)
  {
  	imx_set_cpu_jump(cpu, v7_secondary_startup);
  	imx_enable_cpu(cpu, true);
  	return 0;
  }
  
  /*
   * Initialise the CPU possible map early - this describes the CPUs
   * which may be present or become present in the system.
   */
  static void __init imx_smp_init_cpus(void)
  {
  	int i, ncores = scu_get_core_count(imx_scu_base);
  	u32 me = smp_processor_id();
  
  	if (setup_max_cpus < ncores)
  		ncores = (setup_max_cpus) ? setup_max_cpus : 1;
  
  	for (i = ncores; i < NR_CPUS; i++)
  		set_cpu_possible(i, false);
  
  	/* Set the SCU CPU Power status for each inactive core. */
  	for (i = 0; i < NR_CPUS;  i++) {
  		if (i != me)
  			__raw_writeb(SCU_PM_POWEROFF, imx_scu_base + 0x08 + i);
  	}
  }
  
  void imx_smp_prepare(void)
  {
  	scu_enable(imx_scu_base);
  	/* Need to enable SCU standby for entering WAIT mode */
  	imx_scu_standby_enable();
  }
  
  static void __init imx_smp_prepare_cpus(unsigned int max_cpus)
  {
  	imx_smp_prepare();
  
  	/*
  	 * The diagnostic register holds the errata bits.  Mostly bootloader
  	 * does not bring up secondary cores, so that when errata bits are set
  	 * in bootloader, they are set only for boot cpu.  But on a SMP
  	 * configuration, it should be equally done on every single core.
  	 * Read the register from boot cpu here, and will replicate it into
  	 * secondary cores when booting them.
  	 */
  	asm("mrc p15, 0, %0, c15, c0, 1" : "=r" (g_diag_reg) : : "cc");
  	__cpuc_flush_dcache_area(&g_diag_reg, sizeof(g_diag_reg));
  	outer_clean_range(__pa(&g_diag_reg), __pa(&g_diag_reg + 1));
  }
  
  struct smp_operations  imx_smp_ops __initdata = {
  	.smp_init_cpus		= imx_smp_init_cpus,
  	.smp_prepare_cpus	= imx_smp_prepare_cpus,
  	.smp_boot_secondary	= imx_boot_secondary,
  #ifdef CONFIG_HOTPLUG_CPU
  	.cpu_die		= imx_cpu_die,
  	.cpu_kill		= imx_cpu_kill,
  #endif
  };