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kernel/linux-imx6_3.14.28/arch/arm/mach-shmobile/setup-rcar-gen2.c 2.8 KB
6b13f685e   김민수   BSP 최초 추가
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  /*
   * R-Car Generation 2 support
   *
   * Copyright (C) 2013  Renesas Solutions Corp.
   * Copyright (C) 2013  Magnus Damm
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; version 2 of the License.
   *
   * 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.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   */
  
  #include <linux/clk/shmobile.h>
  #include <linux/clocksource.h>
  #include <linux/io.h>
  #include <linux/kernel.h>
  #include <mach/common.h>
  #include <mach/rcar-gen2.h>
  #include <asm/mach/arch.h>
  
  #define MODEMR 0xe6160060
  
  u32 __init rcar_gen2_read_mode_pins(void)
  {
  	void __iomem *modemr = ioremap_nocache(MODEMR, 4);
  	u32 mode;
  
  	BUG_ON(!modemr);
  	mode = ioread32(modemr);
  	iounmap(modemr);
  
  	return mode;
  }
  
  #define CNTCR 0
  #define CNTFID0 0x20
  
  void __init rcar_gen2_timer_init(void)
  {
  #if defined(CONFIG_ARM_ARCH_TIMER) || defined(CONFIG_COMMON_CLK)
  	u32 mode = rcar_gen2_read_mode_pins();
  #endif
  #ifdef CONFIG_ARM_ARCH_TIMER
  	void __iomem *base;
  	int extal_mhz = 0;
  	u32 freq;
  
  	/* At Linux boot time the r8a7790 arch timer comes up
  	 * with the counter disabled. Moreover, it may also report
  	 * a potentially incorrect fixed 13 MHz frequency. To be
  	 * correct these registers need to be updated to use the
  	 * frequency EXTAL / 2 which can be determined by the MD pins.
  	 */
  
  	switch (mode & (MD(14) | MD(13))) {
  	case 0:
  		extal_mhz = 15;
  		break;
  	case MD(13):
  		extal_mhz = 20;
  		break;
  	case MD(14):
  		extal_mhz = 26;
  		break;
  	case MD(13) | MD(14):
  		extal_mhz = 30;
  		break;
  	}
  
  	/* The arch timer frequency equals EXTAL / 2 */
  	freq = extal_mhz * (1000000 / 2);
  
  	/* Remap "armgcnt address map" space */
  	base = ioremap(0xe6080000, PAGE_SIZE);
  
  	/*
  	 * Update the timer if it is either not running, or is not at the
  	 * right frequency. The timer is only configurable in secure mode
  	 * so this avoids an abort if the loader started the timer and
  	 * entered the kernel in non-secure mode.
  	 */
  
  	if ((ioread32(base + CNTCR) & 1) == 0 ||
  	    ioread32(base + CNTFID0) != freq) {
  		/* Update registers with correct frequency */
  		iowrite32(freq, base + CNTFID0);
  		asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq));
  
  		/* make sure arch timer is started by setting bit 0 of CNTCR */
  		iowrite32(1, base + CNTCR);
  	}
  
  	iounmap(base);
  #endif /* CONFIG_ARM_ARCH_TIMER */
  
  #ifdef CONFIG_COMMON_CLK
  	rcar_gen2_clocks_init(mode);
  #endif
  	clocksource_of_init();
  }