1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * omap2-restart.c - code common to all OMAP2xxx machines.
4  *
5  * Copyright (C) 2012 Texas Instruments
6  * Paul Walmsley
7  */
8 #include <linux/kernel.h>
9 #include <linux/init.h>
10 #include <linux/clk.h>
11 #include <linux/io.h>
12 
13 #include "soc.h"
14 #include "common.h"
15 #include "prm.h"
16 
17 /*
18  * reset_virt_prcm_set_ck, reset_sys_ck: pointers to the virt_prcm_set
19  * clock and the sys_ck.  Used during the reset process
20  */
21 static struct clk *reset_virt_prcm_set_ck, *reset_sys_ck;
22 
23 /* Reboot handling */
24 
25 /**
26  * omap2xxx_restart - Set DPLL to bypass mode for reboot to work
27  *
28  * Set the DPLL to bypass so that reboot completes successfully.  No
29  * return value.
30  */
omap2xxx_restart(enum reboot_mode mode,const char * cmd)31 void omap2xxx_restart(enum reboot_mode mode, const char *cmd)
32 {
33 	u32 rate;
34 
35 	rate = clk_get_rate(reset_sys_ck);
36 	clk_set_rate(reset_virt_prcm_set_ck, rate);
37 
38 	/* XXX Should save the cmd argument for use after the reboot */
39 
40 	omap_prm_reset_system();
41 }
42 
43 /**
44  * omap2xxx_common_look_up_clks_for_reset - look up clocks needed for restart
45  *
46  * Some clocks need to be looked up in advance for the SoC restart
47  * operation to work - see omap2xxx_restart().  Returns -EINVAL upon
48  * error or 0 upon success.
49  */
omap2xxx_common_look_up_clks_for_reset(void)50 static int __init omap2xxx_common_look_up_clks_for_reset(void)
51 {
52 	reset_virt_prcm_set_ck = clk_get(NULL, "virt_prcm_set");
53 	if (IS_ERR(reset_virt_prcm_set_ck))
54 		return -EINVAL;
55 
56 	reset_sys_ck = clk_get(NULL, "sys_ck");
57 	if (IS_ERR(reset_sys_ck))
58 		return -EINVAL;
59 
60 	return 0;
61 }
62 omap_postcore_initcall(omap2xxx_common_look_up_clks_for_reset);
63