xref: /OK3568_Linux_fs/kernel/arch/arm/mach-omap1/reset.c (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun  * OMAP1 reset support
4*4882a593Smuzhiyun  */
5*4882a593Smuzhiyun #include <linux/kernel.h>
6*4882a593Smuzhiyun #include <linux/io.h>
7*4882a593Smuzhiyun #include <linux/reboot.h>
8*4882a593Smuzhiyun 
9*4882a593Smuzhiyun #include <mach/hardware.h>
10*4882a593Smuzhiyun 
11*4882a593Smuzhiyun #include "iomap.h"
12*4882a593Smuzhiyun #include "common.h"
13*4882a593Smuzhiyun 
14*4882a593Smuzhiyun /* ARM_SYSST bit shifts related to SoC reset sources */
15*4882a593Smuzhiyun #define ARM_SYSST_POR_SHIFT				5
16*4882a593Smuzhiyun #define ARM_SYSST_EXT_RST_SHIFT				4
17*4882a593Smuzhiyun #define ARM_SYSST_ARM_WDRST_SHIFT			2
18*4882a593Smuzhiyun #define ARM_SYSST_GLOB_SWRST_SHIFT			1
19*4882a593Smuzhiyun 
20*4882a593Smuzhiyun /* Standardized reset source bits (across all OMAP SoCs) */
21*4882a593Smuzhiyun #define OMAP_GLOBAL_COLD_RST_SRC_ID_SHIFT		0
22*4882a593Smuzhiyun #define OMAP_GLOBAL_WARM_RST_SRC_ID_SHIFT		1
23*4882a593Smuzhiyun #define OMAP_MPU_WD_RST_SRC_ID_SHIFT			3
24*4882a593Smuzhiyun #define OMAP_EXTWARM_RST_SRC_ID_SHIFT			5
25*4882a593Smuzhiyun 
26*4882a593Smuzhiyun 
omap1_restart(enum reboot_mode mode,const char * cmd)27*4882a593Smuzhiyun void omap1_restart(enum reboot_mode mode, const char *cmd)
28*4882a593Smuzhiyun {
29*4882a593Smuzhiyun 	/*
30*4882a593Smuzhiyun 	 * Workaround for 5912/1611b bug mentioned in sprz209d.pdf p. 28
31*4882a593Smuzhiyun 	 * "Global Software Reset Affects Traffic Controller Frequency".
32*4882a593Smuzhiyun 	 */
33*4882a593Smuzhiyun 	if (cpu_is_omap5912()) {
34*4882a593Smuzhiyun 		omap_writew(omap_readw(DPLL_CTL) & ~(1 << 4), DPLL_CTL);
35*4882a593Smuzhiyun 		omap_writew(0x8, ARM_RSTCT1);
36*4882a593Smuzhiyun 	}
37*4882a593Smuzhiyun 
38*4882a593Smuzhiyun 	omap_writew(1, ARM_RSTCT1);
39*4882a593Smuzhiyun }
40*4882a593Smuzhiyun 
41*4882a593Smuzhiyun /**
42*4882a593Smuzhiyun  * omap1_get_reset_sources - return the source of the SoC's last reset
43*4882a593Smuzhiyun  *
44*4882a593Smuzhiyun  * Returns bits that represent the last reset source for the SoC.  The
45*4882a593Smuzhiyun  * format is standardized across OMAPs for use by the OMAP watchdog.
46*4882a593Smuzhiyun  */
omap1_get_reset_sources(void)47*4882a593Smuzhiyun u32 omap1_get_reset_sources(void)
48*4882a593Smuzhiyun {
49*4882a593Smuzhiyun 	u32 ret = 0;
50*4882a593Smuzhiyun 	u16 rs;
51*4882a593Smuzhiyun 
52*4882a593Smuzhiyun 	rs = __raw_readw(OMAP1_IO_ADDRESS(ARM_SYSST));
53*4882a593Smuzhiyun 
54*4882a593Smuzhiyun 	if (rs & (1 << ARM_SYSST_POR_SHIFT))
55*4882a593Smuzhiyun 		ret |= 1 << OMAP_GLOBAL_COLD_RST_SRC_ID_SHIFT;
56*4882a593Smuzhiyun 	if (rs & (1 << ARM_SYSST_EXT_RST_SHIFT))
57*4882a593Smuzhiyun 		ret |= 1 << OMAP_EXTWARM_RST_SRC_ID_SHIFT;
58*4882a593Smuzhiyun 	if (rs & (1 << ARM_SYSST_ARM_WDRST_SHIFT))
59*4882a593Smuzhiyun 		ret |= 1 << OMAP_MPU_WD_RST_SRC_ID_SHIFT;
60*4882a593Smuzhiyun 	if (rs & (1 << ARM_SYSST_GLOB_SWRST_SHIFT))
61*4882a593Smuzhiyun 		ret |= 1 << OMAP_GLOBAL_WARM_RST_SRC_ID_SHIFT;
62*4882a593Smuzhiyun 
63*4882a593Smuzhiyun 	return ret;
64*4882a593Smuzhiyun }
65