/*
   * Copyright (c) 2014 Google, Inc.
   *
   * SPDX-License-Identifier:     GPL-2.0+
   */
  
  #define IOTRACE_IMPL
  
  #include <common.h>
  #include <asm/io.h>
  
  DECLARE_GLOBAL_DATA_PTR;
  
  /* Support up to the machine word length for now */
  typedef ulong iovalue_t;
  
  enum iotrace_flags {
  	IOT_8 = 0,
  	IOT_16,
  	IOT_32,
  
  	IOT_READ = 0 << 3,
  	IOT_WRITE = 1 << 3,
  };
  
  /**
   * struct iotrace_record - Holds a single I/O trace record
   *
   * @flags: I/O access type
   * @addr: Address of access
   * @value: Value written or read
   */
  struct iotrace_record {
  	enum iotrace_flags flags;
  	phys_addr_t addr;
  	iovalue_t value;
  };
  
  /**
   * struct iotrace - current trace status and checksum
   *
   * @start:	Start address of iotrace buffer
   * @size:	Size of iotrace buffer in bytes
   * @offset:	Current write offset into iotrace buffer
   * @crc32:	Current value of CRC chceksum of trace records
   * @enabled:	true if enabled, false if disabled
   */
  static struct iotrace {
  	ulong start;
  	ulong size;
  	ulong offset;
  	u32 crc32;
  	bool enabled;
  } iotrace;
  
  static void add_record(int flags, const void *ptr, ulong value)
  {
  	struct iotrace_record srec, *rec = &srec;
  
  	/*
  	 * We don't support iotrace before relocation. Since the trace buffer
  	 * is set up by a command, it can't be enabled at present. To change
  	 * this we would need to set the iotrace buffer at build-time. See
  	 * lib/trace.c for how this might be done if you are interested.
  	 */
  	if (!(gd->flags & GD_FLG_RELOC) || !iotrace.enabled)
  		return;
  
  	/* Store it if there is room */
  	if (iotrace.offset + sizeof(*rec) < iotrace.size) {
  		rec = (struct iotrace_record *)map_sysmem(
  					iotrace.start + iotrace.offset,
  					sizeof(value));
  	}
  
  	rec->flags = flags;
  	rec->addr = map_to_sysmem(ptr);
  	rec->value = value;
  
  	/* Update our checksum */
  	iotrace.crc32 = crc32(iotrace.crc32, (unsigned char *)rec,
  			      sizeof(*rec));
  
  	iotrace.offset += sizeof(struct iotrace_record);
  }
  
  u32 iotrace_readl(const void *ptr)
  {
  	u32 v;
  
  	v = readl(ptr);
  	add_record(IOT_32 | IOT_READ, ptr, v);
  
  	return v;
  }
  
  void iotrace_writel(ulong value, const void *ptr)
  {
  	add_record(IOT_32 | IOT_WRITE, ptr, value);
  	writel(value, ptr);
  }
  
  u16 iotrace_readw(const void *ptr)
  {
  	u32 v;
  
  	v = readw(ptr);
  	add_record(IOT_16 | IOT_READ, ptr, v);
  
  	return v;
  }
  
  void iotrace_writew(ulong value, const void *ptr)
  {
  	add_record(IOT_16 | IOT_WRITE, ptr, value);
  	writew(value, ptr);
  }
  
  u8 iotrace_readb(const void *ptr)
  {
  	u32 v;
  
  	v = readb(ptr);
  	add_record(IOT_8 | IOT_READ, ptr, v);
  
  	return v;
  }
  
  void iotrace_writeb(ulong value, const void *ptr)
  {
  	add_record(IOT_8 | IOT_WRITE, ptr, value);
  	writeb(value, ptr);
  }
  
  void iotrace_reset_checksum(void)
  {
  	iotrace.crc32 = 0;
  }
  
  u32 iotrace_get_checksum(void)
  {
  	return iotrace.crc32;
  }
  
  void iotrace_set_enabled(int enable)
  {
  	iotrace.enabled = enable;
  }
  
  int iotrace_get_enabled(void)
  {
  	return iotrace.enabled;
  }
  
  void iotrace_set_buffer(ulong start, ulong size)
  {
  	iotrace.start = start;
  	iotrace.size = size;
  	iotrace.offset = 0;
  	iotrace.crc32 = 0;
  }
  
  void iotrace_get_buffer(ulong *start, ulong *size, ulong *offset, ulong *count)
  {
  	*start = iotrace.start;
  	*size = iotrace.size;
  	*offset = iotrace.offset;
  	*count = iotrace.offset / sizeof(struct iotrace_record);
  }