arm/mach-omap1/reset.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * OMAP1 reset support
0004  */
0005 #include <linux/kernel.h>
0006 #include <linux/io.h>
0007 #include <linux/reboot.h>
0008
0009 #include "hardware.h"
0010 #include "iomap.h"
0011 #include "common.h"
0012
0013 /* ARM_SYSST bit shifts related to SoC reset sources */
0014 #define ARM_SYSST_POR_SHIFT             5
0015 #define ARM_SYSST_EXT_RST_SHIFT             4
0016 #define ARM_SYSST_ARM_WDRST_SHIFT           2
0017 #define ARM_SYSST_GLOB_SWRST_SHIFT          1
0018
0019 /* Standardized reset source bits (across all OMAP SoCs) */
0020 #define OMAP_GLOBAL_COLD_RST_SRC_ID_SHIFT       0
0021 #define OMAP_GLOBAL_WARM_RST_SRC_ID_SHIFT       1
0022 #define OMAP_MPU_WD_RST_SRC_ID_SHIFT            3
0023 #define OMAP_EXTWARM_RST_SRC_ID_SHIFT           5
0024
0025
0026 void omap1_restart(enum reboot_mode mode, const char *cmd)
0027 {
0028     /*
0029      * Workaround for 5912/1611b bug mentioned in sprz209d.pdf p. 28
0030      * "Global Software Reset Affects Traffic Controller Frequency".
0031      */
0032     if (cpu_is_omap5912()) {
0033         omap_writew(omap_readw(DPLL_CTL) & ~(1 << 4), DPLL_CTL);
0034         omap_writew(0x8, ARM_RSTCT1);
0035     }
0036
0037     omap_writew(1, ARM_RSTCT1);
0038 }
0039
0040 /**
0041  * omap1_get_reset_sources - return the source of the SoC's last reset
0042  *
0043  * Returns bits that represent the last reset source for the SoC.  The
0044  * format is standardized across OMAPs for use by the OMAP watchdog.
0045  */
0046 u32 omap1_get_reset_sources(void)
0047 {
0048     u32 ret = 0;
0049     u16 rs;
0050
0051     rs = __raw_readw(OMAP1_IO_ADDRESS(ARM_SYSST));
0052
0053     if (rs & (1 << ARM_SYSST_POR_SHIFT))
0054         ret |= 1 << OMAP_GLOBAL_COLD_RST_SRC_ID_SHIFT;
0055     if (rs & (1 << ARM_SYSST_EXT_RST_SHIFT))
0056         ret |= 1 << OMAP_EXTWARM_RST_SRC_ID_SHIFT;
0057     if (rs & (1 << ARM_SYSST_ARM_WDRST_SHIFT))
0058         ret |= 1 << OMAP_MPU_WD_RST_SRC_ID_SHIFT;
0059     if (rs & (1 << ARM_SYSST_GLOB_SWRST_SHIFT))
0060         ret |= 1 << OMAP_GLOBAL_WARM_RST_SRC_ID_SHIFT;
0061
0062     return ret;
0063 }