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         memcpy(&our_buf[r], val, val_len);
  45
  46         for (i = 0; i < val_len / 2; i++)
  47                 data->written[r + i] = true;
  48
  49         return 0;
  50 }
  51
  52 static int regmap_raw_ram_write(void *context, const void *data, size_t count)
  53 {
  54         return regmap_raw_ram_gather_write(context, data, 2,
  55                                            data + 2, count - 2);
  56 }
  57
  58 static int regmap_raw_ram_read(void *context,
  59                                const void *reg, size_t reg_len,
  60                                void *val, size_t val_len)
  61 {
  62         struct regmap_ram_data *data = context;
  63         unsigned int r;
  64         u16 *our_buf = (u16 *)data->vals;
  65         int i;
  66
  67         if (reg_len != 2)
  68                 return -EINVAL;
  69         if (val_len % 2)
  70                 return -EINVAL;
  71
  72         r = decode_reg(data->reg_endian, reg);
  73         memcpy(val, &our_buf[r], val_len);
  74
  75         for (i = 0; i < val_len / 2; i++)
  76                 data->read[r + i] = true;
  77
  78         return 0;
  79 }
  80
  81 static void regmap_raw_ram_free_context(void *context)
  82 {
  83         struct regmap_ram_data *data = context;
  84
  85         kfree(data->vals);
  86         kfree(data->read);
  87         kfree(data->written);
  88         kfree(data);
  89 }
  90
  91 static const struct regmap_bus regmap_raw_ram = {
  92         .fast_io = true,
  93         .write = regmap_raw_ram_write,
  94         .gather_write = regmap_raw_ram_gather_write,
  95         .read = regmap_raw_ram_read,
  96         .free_context = regmap_raw_ram_free_context,
  97 };
  98
  99 struct regmap *__regmap_init_raw_ram(const struct regmap_config *config,
 100                                      struct regmap_ram_data *data,
 101                                      struct lock_class_key *lock_key,
 102                                      const char *lock_name)
 103 {
 104         struct regmap *map;
 105
 106         if (config->reg_bits != 16)
 107                 return ERR_PTR(-EINVAL);
 108
 109         if (!config->max_register) {
 110                 pr_crit("No max_register specified for RAM regmap\n");
 111                 return ERR_PTR(-EINVAL);
 112         }
 113
 114         data->read = kcalloc(sizeof(bool), config->max_register + 1,
 115                              GFP_KERNEL);
 116         if (!data->read)
 117                 return ERR_PTR(-ENOMEM);
 118
 119         data->written = kcalloc(sizeof(bool), config->max_register + 1,
 120                                 GFP_KERNEL);
 121         if (!data->written)
 122                 return ERR_PTR(-ENOMEM);
 123
 124         data->reg_endian = config->reg_format_endian;
 125
 126         map = __regmap_init(NULL, &regmap_raw_ram, data, config,
 127                             lock_key, lock_name);
 128
 129         return map;
 130 }
 131 EXPORT_SYMBOL_GPL(__regmap_init_raw_ram);
 132
 133 MODULE_LICENSE("GPL v2");