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
 15static 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 */
 24struct 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 */
 57int 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 */
 94int 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 */
121int 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 */
154void 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
167void tb_nvm_exit(void)
168{
169	ida_destroy(&nvm_ida);
170}