drivers/platform/chrome/cros_ec_lpc_reg.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // LPC interface for ChromeOS Embedded Controller
   3 //
   4 // Copyright (C) 2016 Google, Inc
   5
   6 #include <linux/io.h>
   7 #include <linux/mfd/cros_ec.h>
   8 #include <linux/mfd/cros_ec_commands.h>
   9
  10 #include "cros_ec_lpc_mec.h"
  11
  12 static u8 lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest)
  13 {
  14         int i;
  15         int sum = 0;
  16
  17         for (i = 0; i < length; ++i) {
  18                 dest[i] = inb(offset + i);
  19                 sum += dest[i];
  20         }
  21
  22         /* Return checksum of all bytes read */
  23         return sum;
  24 }
  25
  26 static u8 lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg)
  27 {
  28         int i;
  29         int sum = 0;
  30
  31         for (i = 0; i < length; ++i) {
  32                 outb(msg[i], offset + i);
  33                 sum += msg[i];
  34         }
  35
  36         /* Return checksum of all bytes written */
  37         return sum;
  38 }
  39
  40 #ifdef CONFIG_CROS_EC_LPC_MEC
  41
  42 u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest)
  43 {
  44         int in_range = cros_ec_lpc_mec_in_range(offset, length);
  45
  46         if (in_range < 0)
  47                 return 0;
  48
  49         return in_range ?
  50                 cros_ec_lpc_io_bytes_mec(MEC_IO_READ,
  51                                          offset - EC_HOST_CMD_REGION0,
  52                                          length, dest) :
  53                 lpc_read_bytes(offset, length, dest);
  54 }
  55
  56 u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg)
  57 {
  58         int in_range = cros_ec_lpc_mec_in_range(offset, length);
  59
  60         if (in_range < 0)
  61                 return 0;
  62
  63         return in_range ?
  64                 cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE,
  65                                          offset - EC_HOST_CMD_REGION0,
  66                                          length, msg) :
  67                 lpc_write_bytes(offset, length, msg);
  68 }
  69
  70 void cros_ec_lpc_reg_init(void)
  71 {
  72         cros_ec_lpc_mec_init(EC_HOST_CMD_REGION0,
  73                              EC_LPC_ADDR_MEMMAP + EC_MEMMAP_SIZE);
  74 }
  75
  76 void cros_ec_lpc_reg_destroy(void)
  77 {
  78         cros_ec_lpc_mec_destroy();
  79 }
  80
  81 #else /* CONFIG_CROS_EC_LPC_MEC */
  82
  83 u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest)
  84 {
  85         return lpc_read_bytes(offset, length, dest);
  86 }
  87
  88 u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg)
  89 {
  90         return lpc_write_bytes(offset, length, msg);
  91 }
  92
  93 void cros_ec_lpc_reg_init(void)
  94 {
  95 }
  96
  97 void cros_ec_lpc_reg_destroy(void)
  98 {
  99 }
 100
 101 #endif /* CONFIG_CROS_EC_LPC_MEC */