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((drv), struct nvmem_layout_driver, driver)) 21 #define to_nvmem_layout_device(_dev) \ 22 container_of((_dev), struct nvmem_layout, dev) 23 24 static int nvmem_layout_bus_match(struct device *dev, struct device_driver *drv) 25 { 26 return of_driver_match_device(dev, drv); 27 } 28 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 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 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 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 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 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 }; 119 120 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_get_property(layout_dn, "compatible", NULL)) { 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 } 154 155 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 */ 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 } 182 183 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 } 194 195 int nvmem_layout_bus_register(void) 196 { 197 return bus_register(&nvmem_layout_bus_type); 198 } 199 200 void nvmem_layout_bus_unregister(void) 201 { 202 bus_unregister(&nvmem_layout_bus_type); 203 } 204