text: // SPDX-License-Identifier: GPL-2.0
  #include <base/common.h>
  #include <base/types.h>
  #include <base/init.h>
  
  #include <minix_rt/memory.h>
  
  static u64 patterns[] __initdata = {
  	/* The first entry has to be 0 to leave memtest with zeroed memory */
  	0,
  	0xffffffffffffffffULL,
  	0x5555555555555555ULL,
  	0xaaaaaaaaaaaaaaaaULL,
  	0x1111111111111111ULL,
  	0x2222222222222222ULL,
  	0x4444444444444444ULL,
  	0x8888888888888888ULL,
  	0x3333333333333333ULL,
  	0x6666666666666666ULL,
  	0x9999999999999999ULL,
  	0xccccccccccccccccULL,
  	0x7777777777777777ULL,
  	0xbbbbbbbbbbbbbbbbULL,
  	0xddddddddddddddddULL,
  	0xeeeeeeeeeeeeeeeeULL,
  	0x7a6c7258554e494cULL, /* yeah ;-) */
  };
  
  static void __init reserve_bad_mem(u64 pattern, phys_addr_t start_bad, phys_addr_t end_bad)
  {
  	printf("  %016llx bad mem addr 0x%016llx - 0x%016llx reserved\n",
  		cpu_to_be64(pattern), start_bad, end_bad);
  	memblock_reserve(&memblock_kernel, start_bad, end_bad - start_bad);
  }
  
  static void __init memtest(u64 pattern, phys_addr_t start_phys, phys_addr_t size)
  {
  	u64 *p, *start, *end;
  	phys_addr_t start_bad, last_bad;
  	phys_addr_t start_phys_aligned;
  	const size_t incr = sizeof(pattern);
  
  	start_phys_aligned = ALIGN(start_phys, incr);
  	start = __va(start_phys_aligned);
  	end = start + (size - (start_phys_aligned - start_phys)) / incr;
  	start_bad = 0;
  	last_bad = 0;
  
  	for (p = start; p < end; p++)
  		*p = pattern;
  
  	for (p = start; p < end; p++, start_phys_aligned += incr) {
  		if (*p == pattern)
  			continue;
  		if (start_phys_aligned == last_bad + incr) {
  			last_bad += incr;
  			continue;
  		}
  		if (start_bad)
  			reserve_bad_mem(pattern, start_bad, last_bad + incr);
  		start_bad = last_bad = start_phys_aligned;
  	}
  	if (start_bad)
  		reserve_bad_mem(pattern, start_bad, last_bad + incr);
  }
  
  static void __init do_one_pass(u64 pattern, phys_addr_t start, phys_addr_t end)
  {
  	u64 i;
  	phys_addr_t this_start, this_end;
  
  	for_each_free_mem_range(&memblock_kernel, i, MEMBLOCK_NONE, &this_start,
  				&this_end) {
  		this_start = clamp(this_start, start, end);
  		this_end = clamp(this_end, start, end);
  		if (this_start < this_end) {
  			printf("  0x%016llx - 0x%016llx pattern %016llx\n",
  				this_start, this_end, cpu_to_be64(pattern));
  			memtest(pattern, this_start, this_end - this_start);
  		}
  	}
  }
  
  void __init early_memtest(phys_addr_t start, phys_addr_t end)
  {
  	unsigned int i;
  	unsigned int idx = 0;
      unsigned int memtest_pattern = ARRAY_SIZE(patterns);
  
  	printf("early_memtest: # of tests: %u\n", memtest_pattern);
  	for (i = memtest_pattern-1; i < UINT_MAX; --i) {
  		idx = i % ARRAY_SIZE(patterns);
  		do_one_pass(patterns[idx], start, end);
  	}
  }
  