arch/arm/mach-omap1/reset.c

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