arch/arm/mach-omap2/omap2-restart.c

   1 /*
   2  * omap2-restart.c - code common to all OMAP2xxx machines.
   3  *
   4  * Copyright (C) 2012 Texas Instruments
   5  * Paul Walmsley
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/clk.h>
  14 #include <linux/io.h>
  15
  16 #include "soc.h"
  17 #include "common.h"
  18 #include "prm2xxx.h"
  19
  20 /*
  21  * reset_virt_prcm_set_ck, reset_sys_ck: pointers to the virt_prcm_set
  22  * clock and the sys_ck.  Used during the reset process
  23  */
  24 static struct clk *reset_virt_prcm_set_ck, *reset_sys_ck;
  25
  26 /* Reboot handling */
  27
  28 /**
  29  * omap2xxx_restart - Set DPLL to bypass mode for reboot to work
  30  *
  31  * Set the DPLL to bypass so that reboot completes successfully.  No
  32  * return value.
  33  */
  34 void omap2xxx_restart(enum reboot_mode mode, const char *cmd)
  35 {
  36         u32 rate;
  37
  38         rate = clk_get_rate(reset_sys_ck);
  39         clk_set_rate(reset_virt_prcm_set_ck, rate);
  40
  41         /* XXX Should save the cmd argument for use after the reboot */
  42
  43         omap2xxx_prm_dpll_reset(); /* never returns */
  44         while (1);
  45 }
  46
  47 /**
  48  * omap2xxx_common_look_up_clks_for_reset - look up clocks needed for restart
  49  *
  50  * Some clocks need to be looked up in advance for the SoC restart
  51  * operation to work - see omap2xxx_restart().  Returns -EINVAL upon
  52  * error or 0 upon success.
  53  */
  54 static int __init omap2xxx_common_look_up_clks_for_reset(void)
  55 {
  56         reset_virt_prcm_set_ck = clk_get(NULL, "virt_prcm_set");
  57         if (IS_ERR(reset_virt_prcm_set_ck))
  58                 return -EINVAL;
  59
  60         reset_sys_ck = clk_get(NULL, "sys_ck");
  61         if (IS_ERR(reset_sys_ck))
  62                 return -EINVAL;
  63
  64         return 0;
  65 }
  66 omap_core_initcall(omap2xxx_common_look_up_clks_for_reset);