1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * NVMEM layout bus handling
4 *
5 * Copyright (C) 2023 Bootlin
6 * Author: Miquel Raynal <miquel.raynal@bootlin.com
7 */
8
9 #include <linux/device.h>
10 #include <linux/dma-mapping.h>
11 #include <linux/nvmem-consumer.h>
12 #include <linux/nvmem-provider.h>
13 #include <linux/of.h>
14 #include <linux/of_device.h>
15 #include <linux/of_irq.h>
16
17 #include "internals.h"
18
19 #define to_nvmem_layout_driver(drv) \
20 (container_of_const((drv), struct nvmem_layout_driver, driver))
21 #define to_nvmem_layout_device(_dev) \
22 container_of((_dev), struct nvmem_layout, dev)
23
nvmem_layout_bus_match(struct device * dev,const struct device_driver * drv)24 static int nvmem_layout_bus_match(struct device *dev, const struct device_driver *drv)
25 {
26 return of_driver_match_device(dev, drv);
27 }
28
nvmem_layout_bus_probe(struct device * dev)29 static int nvmem_layout_bus_probe(struct device *dev)
30 {
31 struct nvmem_layout_driver *drv = to_nvmem_layout_driver(dev->driver);
32 struct nvmem_layout *layout = to_nvmem_layout_device(dev);
33
34 if (!drv->probe || !drv->remove)
35 return -EINVAL;
36
37 return drv->probe(layout);
38 }
39
nvmem_layout_bus_remove(struct device * dev)40 static void nvmem_layout_bus_remove(struct device *dev)
41 {
42 struct nvmem_layout_driver *drv = to_nvmem_layout_driver(dev->driver);
43 struct nvmem_layout *layout = to_nvmem_layout_device(dev);
44
45 return drv->remove(layout);
46 }
47
48 static const struct bus_type nvmem_layout_bus_type = {
49 .name = "nvmem-layout",
50 .match = nvmem_layout_bus_match,
51 .probe = nvmem_layout_bus_probe,
52 .remove = nvmem_layout_bus_remove,
53 };
54
__nvmem_layout_driver_register(struct nvmem_layout_driver * drv,struct module * owner)55 int __nvmem_layout_driver_register(struct nvmem_layout_driver *drv,
56 struct module *owner)
57 {
58 drv->driver.bus = &nvmem_layout_bus_type;
59 drv->driver.owner = owner;
60
61 return driver_register(&drv->driver);
62 }
63 EXPORT_SYMBOL_GPL(__nvmem_layout_driver_register);
64
nvmem_layout_driver_unregister(struct nvmem_layout_driver * drv)65 void nvmem_layout_driver_unregister(struct nvmem_layout_driver *drv)
66 {
67 driver_unregister(&drv->driver);
68 }
69 EXPORT_SYMBOL_GPL(nvmem_layout_driver_unregister);
70
nvmem_layout_release_device(struct device * dev)71 static void nvmem_layout_release_device(struct device *dev)
72 {
73 struct nvmem_layout *layout = to_nvmem_layout_device(dev);
74
75 of_node_put(layout->dev.of_node);
76 kfree(layout);
77 }
78
nvmem_layout_create_device(struct nvmem_device * nvmem,struct device_node * np)79 static int nvmem_layout_create_device(struct nvmem_device *nvmem,
80 struct device_node *np)
81 {
82 struct nvmem_layout *layout;
83 struct device *dev;
84 int ret;
85
86 layout = kzalloc(sizeof(*layout), GFP_KERNEL);
87 if (!layout)
88 return -ENOMEM;
89
90 /* Create a bidirectional link */
91 layout->nvmem = nvmem;
92 nvmem->layout = layout;
93
94 /* Device model registration */
95 dev = &layout->dev;
96 device_initialize(dev);
97 dev->parent = &nvmem->dev;
98 dev->bus = &nvmem_layout_bus_type;
99 dev->release = nvmem_layout_release_device;
100 dev->coherent_dma_mask = DMA_BIT_MASK(32);
101 dev->dma_mask = &dev->coherent_dma_mask;
102 device_set_node(dev, of_fwnode_handle(of_node_get(np)));
103 of_device_make_bus_id(dev);
104 of_msi_configure(dev, dev->of_node);
105
106 ret = device_add(dev);
107 if (ret) {
108 put_device(dev);
109 return ret;
110 }
111
112 return 0;
113 }
114
115 static const struct of_device_id of_nvmem_layout_skip_table[] = {
116 { .compatible = "fixed-layout", },
117 {}
118 };
119
nvmem_layout_bus_populate(struct nvmem_device * nvmem,struct device_node * layout_dn)120 static int nvmem_layout_bus_populate(struct nvmem_device *nvmem,
121 struct device_node *layout_dn)
122 {
123 int ret;
124
125 /* Make sure it has a compatible property */
126 if (!of_property_present(layout_dn, "compatible")) {
127 pr_debug("%s() - skipping %pOF, no compatible prop\n",
128 __func__, layout_dn);
129 return 0;
130 }
131
132 /* Fixed layouts are parsed manually somewhere else for now */
133 if (of_match_node(of_nvmem_layout_skip_table, layout_dn)) {
134 pr_debug("%s() - skipping %pOF node\n", __func__, layout_dn);
135 return 0;
136 }
137
138 if (of_node_check_flag(layout_dn, OF_POPULATED_BUS)) {
139 pr_debug("%s() - skipping %pOF, already populated\n",
140 __func__, layout_dn);
141
142 return 0;
143 }
144
145 /* NVMEM layout buses expect only a single device representing the layout */
146 ret = nvmem_layout_create_device(nvmem, layout_dn);
147 if (ret)
148 return ret;
149
150 of_node_set_flag(layout_dn, OF_POPULATED_BUS);
151
152 return 0;
153 }
154
of_nvmem_layout_get_container(struct nvmem_device * nvmem)155 struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem)
156 {
157 return of_get_child_by_name(nvmem->dev.of_node, "nvmem-layout");
158 }
159 EXPORT_SYMBOL_GPL(of_nvmem_layout_get_container);
160
161 /*
162 * Returns the number of devices populated, 0 if the operation was not relevant
163 * for this nvmem device, an error code otherwise.
164 */
nvmem_populate_layout(struct nvmem_device * nvmem)165 int nvmem_populate_layout(struct nvmem_device *nvmem)
166 {
167 struct device_node *layout_dn;
168 int ret;
169
170 layout_dn = of_nvmem_layout_get_container(nvmem);
171 if (!layout_dn)
172 return 0;
173
174 /* Populate the layout device */
175 device_links_supplier_sync_state_pause();
176 ret = nvmem_layout_bus_populate(nvmem, layout_dn);
177 device_links_supplier_sync_state_resume();
178
179 of_node_put(layout_dn);
180 return ret;
181 }
182
nvmem_destroy_layout(struct nvmem_device * nvmem)183 void nvmem_destroy_layout(struct nvmem_device *nvmem)
184 {
185 struct device *dev;
186
187 if (!nvmem->layout)
188 return;
189
190 dev = &nvmem->layout->dev;
191 of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
192 device_unregister(dev);
193 }
194
nvmem_layout_bus_register(void)195 int nvmem_layout_bus_register(void)
196 {
197 return bus_register(&nvmem_layout_bus_type);
198 }
199
nvmem_layout_bus_unregister(void)200 void nvmem_layout_bus_unregister(void)
201 {
202 bus_unregister(&nvmem_layout_bus_type);
203 }
204