#include <stdint.h> #include <pc80/mc146818rtc.h> #include <fallback.h> #if CONFIG_USE_OPTION_TABLE #include "option_table.h" #endif #ifndef CONFIG_MAX_REBOOT_CNT #error "CONFIG_MAX_REBOOT_CNT not defined" #endif #if CONFIG_MAX_REBOOT_CNT > 15 #error "CONFIG_MAX_REBOOT_CNT too high" #endif static int cmos_error(void) { unsigned char reg_d; /* See if the cmos error condition has been flagged */ reg_d = cmos_read(RTC_REG_D); return (reg_d & RTC_VRT) == 0; } static int cmos_chksum_valid(void) { #if CONFIG_USE_OPTION_TABLE unsigned char addr; u16 sum, old_sum; sum = 0; /* Compute the cmos checksum */ for(addr = LB_CKS_RANGE_START; addr <= LB_CKS_RANGE_END; addr++) { sum += cmos_read(addr); } /* Read the stored checksum */ old_sum = cmos_read(LB_CKS_LOC) << 8; old_sum |= cmos_read(LB_CKS_LOC+1); return sum == old_sum; #else return 0; #endif } static inline int last_boot_normal(void) { unsigned char byte; byte = cmos_read(RTC_BOOT_BYTE); return (byte & (1 << 1)); } static inline int do_normal_boot(void) { unsigned char byte; if (cmos_error() || !cmos_chksum_valid()) { /* There are no impossible values, no checksums so just * trust whatever value we have in the the cmos, * but clear the fallback bit. */ byte = cmos_read(RTC_BOOT_BYTE); byte &= 0x0c; byte |= CONFIG_MAX_REBOOT_CNT << 4; cmos_write(byte, RTC_BOOT_BYTE); } /* The RTC_BOOT_BYTE is now o.k. see where to go. */ byte = cmos_read(RTC_BOOT_BYTE); /* Are we in normal mode? */ if (byte & 1) { byte &= 0x0f; /* yes, clear the boot count */ } /* Properly set the last boot flag */ byte &= 0xfc; if ((byte >> 4) < CONFIG_MAX_REBOOT_CNT) { byte |= (1<<1); } /* Are we already at the max count? */ if ((byte >> 4) < CONFIG_MAX_REBOOT_CNT) { byte += 1 << 4; /* No, add 1 to the count */ } else { byte &= 0xfc; /* Yes, put in fallback mode */ } /* Save the boot byte */ cmos_write(byte, RTC_BOOT_BYTE); return (byte & (1<<1)); } unsigned read_option_lowlevel(unsigned start, unsigned size, unsigned def) { #if CONFIG_USE_OPTION_TABLE unsigned byte; byte = cmos_read(start/8); return (byte >> (start & 7U)) & ((1U << size) - 1U); #else return def; #endif }