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 "prm.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 	omap_prm_reset_system();
44 }
45 
46 /**
47  * omap2xxx_common_look_up_clks_for_reset - look up clocks needed for restart
48  *
49  * Some clocks need to be looked up in advance for the SoC restart
50  * operation to work - see omap2xxx_restart().  Returns -EINVAL upon
51  * error or 0 upon success.
52  */
53 static int __init omap2xxx_common_look_up_clks_for_reset(void)
54 {
55 	reset_virt_prcm_set_ck = clk_get(NULL, "virt_prcm_set");
56 	if (IS_ERR(reset_virt_prcm_set_ck))
57 		return -EINVAL;
58 
59 	reset_sys_ck = clk_get(NULL, "sys_ck");
60 	if (IS_ERR(reset_sys_ck))
61 		return -EINVAL;
62 
63 	return 0;
64 }
65 omap_postcore_initcall(omap2xxx_common_look_up_clks_for_reset);
66