xref: /openbmc/u-boot/arch/arm/cpu/armv7/syslib.c (revision 5a75e121)
1 /*
2  * (C) Copyright 2008
3  * Texas Instruments, <www.ti.com>
4  *
5  * Richard Woodruff <r-woodruff2@ti.com>
6  * Syed Mohammed Khasim <khasim@ti.com>
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License as
10  * published by the Free Software Foundation; either version 2 of
11  * the License, or (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21  * MA 02111-1307 USA
22  */
23 
24 #include <common.h>
25 #include <asm/io.h>
26 #include <asm/arch/sys_proto.h>
27 
28 /************************************************************
29  * sdelay() - simple spin loop.  Will be constant time as
30  *  its generally used in bypass conditions only.  This
31  *  is necessary until timers are accessible.
32  *
33  *  not inline to increase chances its in cache when called
34  *************************************************************/
35 void sdelay(unsigned long loops)
36 {
37 	__asm__ volatile ("1:\n" "subs %0, %1, #1\n"
38 			  "bne 1b":"=r" (loops):"0"(loops));
39 }
40 
41 /*****************************************************************
42  * sr32 - clear & set a value in a bit range for a 32 bit address
43  *****************************************************************/
44 void sr32(void *addr, u32 start_bit, u32 num_bits, u32 value)
45 {
46 	u32 tmp, msk = 0;
47 	msk = 1 << num_bits;
48 	--msk;
49 	tmp = readl((u32)addr) & ~(msk << start_bit);
50 	tmp |= value << start_bit;
51 	writel(tmp, (u32)addr);
52 }
53 
54 /*********************************************************************
55  * wait_on_value() - common routine to allow waiting for changes in
56  *   volatile regs.
57  *********************************************************************/
58 u32 wait_on_value(u32 read_bit_mask, u32 match_value, void *read_addr,
59 		  u32 bound)
60 {
61 	u32 i = 0, val;
62 	do {
63 		++i;
64 		val = readl((u32)read_addr) & read_bit_mask;
65 		if (val == match_value)
66 			return 1;
67 		if (i == bound)
68 			return 0;
69 	} while (1);
70 }
71