drivers/base/regmap/regmap-raw-ram.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 //
   3 // Register map access API - Memory region with raw access
   4 //
   5 // This is intended for testing only
   6 //
   7 // Copyright (c) 2023, Arm Ltd
   8
   9 #include <linux/clk.h>
  10 #include <linux/err.h>
  11 #include <linux/io.h>
  12 #include <linux/module.h>
  13 #include <linux/regmap.h>
  14 #include <linux/slab.h>
  15 #include <linux/swab.h>
  16
  17 #include "internal.h"
  18
  19 static unsigned int decode_reg(enum regmap_endian endian, const void *reg)
  20 {
  21         const u16 *r = reg;
  22
  23         if (endian == REGMAP_ENDIAN_BIG)
  24                 return be16_to_cpu(*r);
  25         else
  26                 return le16_to_cpu(*r);
  27 }
  28
  29 static int regmap_raw_ram_gather_write(void *context,
  30                                        const void *reg, size_t reg_len,
  31                                        const void *val, size_t val_len)
  32 {
  33         struct regmap_ram_data *data = context;
  34         unsigned int r;
  35         u16 *our_buf = (u16 *)data->vals;
  36         int i;
  37
  38         if (reg_len != 2)
  39                 return -EINVAL;
  40         if (val_len % 2)
  41                 return -EINVAL;
  42
  43         r = decode_reg(data->reg_endian, reg);
  44         if (data->noinc_reg && data->noinc_reg(data, r)) {
  45                 memcpy(&our_buf[r], val + val_len - 2, 2);
  46                 data->written[r] = true;
  47         } else {
  48                 memcpy(&our_buf[r], val, val_len);
  49
  50                 for (i = 0; i < val_len / 2; i++)
  51                         data->written[r + i] = true;
  52         }
  53
  54         return 0;
  55 }
  56
  57 static int regmap_raw_ram_write(void *context, const void *data, size_t count)
  58 {
  59         return regmap_raw_ram_gather_write(context, data, 2,
  60                                            data + 2, count - 2);
  61 }
  62
  63 static int regmap_raw_ram_read(void *context,
  64                                const void *reg, size_t reg_len,
  65                                void *val, size_t val_len)
  66 {
  67         struct regmap_ram_data *data = context;
  68         unsigned int r;
  69         u16 *our_buf = (u16 *)data->vals;
  70         int i;
  71
  72         if (reg_len != 2)
  73                 return -EINVAL;
  74         if (val_len % 2)
  75                 return -EINVAL;
  76
  77         r = decode_reg(data->reg_endian, reg);
  78         if (data->noinc_reg && data->noinc_reg(data, r)) {
  79                 for (i = 0; i < val_len; i += 2)
  80                         memcpy(val + i, &our_buf[r], 2);
  81                 data->read[r] = true;
  82         } else {
  83                 memcpy(val, &our_buf[r], val_len);
  84
  85                 for (i = 0; i < val_len / 2; i++)
  86                         data->read[r + i] = true;
  87         }
  88
  89         return 0;
  90 }
  91
  92 static void regmap_raw_ram_free_context(void *context)
  93 {
  94         struct regmap_ram_data *data = context;
  95
  96         kfree(data->vals);
  97         kfree(data->read);
  98         kfree(data->written);
  99         kfree(data);
 100 }
 101
 102 static const struct regmap_bus regmap_raw_ram = {
 103         .fast_io = true,
 104         .write = regmap_raw_ram_write,
 105         .gather_write = regmap_raw_ram_gather_write,
 106         .read = regmap_raw_ram_read,
 107         .free_context = regmap_raw_ram_free_context,
 108 };
 109
 110 struct regmap *__regmap_init_raw_ram(const struct regmap_config *config,
 111                                      struct regmap_ram_data *data,
 112                                      struct lock_class_key *lock_key,
 113                                      const char *lock_name)
 114 {
 115         struct regmap *map;
 116
 117         if (config->reg_bits != 16)
 118                 return ERR_PTR(-EINVAL);
 119
 120         if (!config->max_register) {
 121                 pr_crit("No max_register specified for RAM regmap\n");
 122                 return ERR_PTR(-EINVAL);
 123         }
 124
 125         data->read = kcalloc(config->max_register + 1, sizeof(bool),
 126                              GFP_KERNEL);
 127         if (!data->read)
 128                 return ERR_PTR(-ENOMEM);
 129
 130         data->written = kcalloc(config->max_register + 1, sizeof(bool),
 131                                 GFP_KERNEL);
 132         if (!data->written)
 133                 return ERR_PTR(-ENOMEM);
 134
 135         data->reg_endian = config->reg_format_endian;
 136
 137         map = __regmap_init(NULL, &regmap_raw_ram, data, config,
 138                             lock_key, lock_name);
 139
 140         return map;
 141 }
 142 EXPORT_SYMBOL_GPL(__regmap_init_raw_ram);
 143
 144 MODULE_LICENSE("GPL v2");