arch/arm/mach-omap1/reset.c

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