drivers/thunderbolt/nvm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * NVM helpers
   4  *
   5  * Copyright (C) 2020, Intel Corporation
   6  * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
   7  */
   8
   9 #include <linux/idr.h>
  10 #include <linux/slab.h>
  11 #include <linux/vmalloc.h>
  12
  13 #include "tb.h"
  14
  15 static DEFINE_IDA(nvm_ida);
  16
  17 /**
  18  * tb_nvm_alloc() - Allocate new NVM structure
  19  * @dev: Device owning the NVM
  20  *
  21  * Allocates new NVM structure with unique @id and returns it. In case
  22  * of error returns ERR_PTR().
  23  */
  24 struct tb_nvm *tb_nvm_alloc(struct device *dev)
  25 {
  26         struct tb_nvm *nvm;
  27         int ret;
  28
  29         nvm = kzalloc(sizeof(*nvm), GFP_KERNEL);
  30         if (!nvm)
  31                 return ERR_PTR(-ENOMEM);
  32
  33         ret = ida_simple_get(&nvm_ida, 0, 0, GFP_KERNEL);
  34         if (ret < 0) {
  35                 kfree(nvm);
  36                 return ERR_PTR(ret);
  37         }
  38
  39         nvm->id = ret;
  40         nvm->dev = dev;
  41
  42         return nvm;
  43 }
  44
  45 /**
  46  * tb_nvm_add_active() - Adds active NVMem device to NVM
  47  * @nvm: NVM structure
  48  * @size: Size of the active NVM in bytes
  49  * @reg_read: Pointer to the function to read the NVM (passed directly to the
  50  *            NVMem device)
  51  *
  52  * Registers new active NVmem device for @nvm. The @reg_read is called
  53  * directly from NVMem so it must handle possible concurrent access if
  54  * needed. The first parameter passed to @reg_read is @nvm structure.
  55  * Returns %0 in success and negative errno otherwise.
  56  */
  57 int tb_nvm_add_active(struct tb_nvm *nvm, size_t size, nvmem_reg_read_t reg_read)
  58 {
  59         struct nvmem_config config;
  60         struct nvmem_device *nvmem;
  61
  62         memset(&config, 0, sizeof(config));
  63
  64         config.name = "nvm_active";
  65         config.reg_read = reg_read;
  66         config.read_only = true;
  67         config.id = nvm->id;
  68         config.stride = 4;
  69         config.word_size = 4;
  70         config.size = size;
  71         config.dev = nvm->dev;
  72         config.owner = THIS_MODULE;
  73         config.priv = nvm;
  74
  75         nvmem = nvmem_register(&config);
  76         if (IS_ERR(nvmem))
  77                 return PTR_ERR(nvmem);
  78
  79         nvm->active = nvmem;
  80         return 0;
  81 }
  82
  83 /**
  84  * tb_nvm_write_buf() - Write data to @nvm buffer
  85  * @nvm: NVM structure
  86  * @offset: Offset where to write the data
  87  * @val: Data buffer to write
  88  * @bytes: Number of bytes to write
  89  *
  90  * Helper function to cache the new NVM image before it is actually
  91  * written to the flash. Copies @bytes from @val to @nvm->buf starting
  92  * from @offset.
  93  */
  94 int tb_nvm_write_buf(struct tb_nvm *nvm, unsigned int offset, void *val,
  95                      size_t bytes)
  96 {
  97         if (!nvm->buf) {
  98                 nvm->buf = vmalloc(NVM_MAX_SIZE);
  99                 if (!nvm->buf)
 100                         return -ENOMEM;
 101         }
 102
 103         nvm->flushed = false;
 104         nvm->buf_data_size = offset + bytes;
 105         memcpy(nvm->buf + offset, val, bytes);
 106         return 0;
 107 }
 108
 109 /**
 110  * tb_nvm_add_non_active() - Adds non-active NVMem device to NVM
 111  * @nvm: NVM structure
 112  * @size: Size of the non-active NVM in bytes
 113  * @reg_write: Pointer to the function to write the NVM (passed directly
 114  *             to the NVMem device)
 115  *
 116  * Registers new non-active NVmem device for @nvm. The @reg_write is called
 117  * directly from NVMem so it must handle possible concurrent access if
 118  * needed. The first parameter passed to @reg_write is @nvm structure.
 119  * Returns %0 in success and negative errno otherwise.
 120  */
 121 int tb_nvm_add_non_active(struct tb_nvm *nvm, size_t size,
 122                           nvmem_reg_write_t reg_write)
 123 {
 124         struct nvmem_config config;
 125         struct nvmem_device *nvmem;
 126
 127         memset(&config, 0, sizeof(config));
 128
 129         config.name = "nvm_non_active";
 130         config.reg_write = reg_write;
 131         config.root_only = true;
 132         config.id = nvm->id;
 133         config.stride = 4;
 134         config.word_size = 4;
 135         config.size = size;
 136         config.dev = nvm->dev;
 137         config.owner = THIS_MODULE;
 138         config.priv = nvm;
 139
 140         nvmem = nvmem_register(&config);
 141         if (IS_ERR(nvmem))
 142                 return PTR_ERR(nvmem);
 143
 144         nvm->non_active = nvmem;
 145         return 0;
 146 }
 147
 148 /**
 149  * tb_nvm_free() - Release NVM and its resources
 150  * @nvm: NVM structure to release
 151  *
 152  * Releases NVM and the NVMem devices if they were registered.
 153  */
 154 void tb_nvm_free(struct tb_nvm *nvm)
 155 {
 156         if (nvm) {
 157                 if (nvm->non_active)
 158                         nvmem_unregister(nvm->non_active);
 159                 if (nvm->active)
 160                         nvmem_unregister(nvm->active);
 161                 vfree(nvm->buf);
 162                 ida_simple_remove(&nvm_ida, nvm->id);
 163         }
 164         kfree(nvm);
 165 }
 166
 167 void tb_nvm_exit(void)
 168 {
 169         ida_destroy(&nvm_ida);
 170 }