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 { 57 drv->driver.bus = &nvmem_layout_bus_type; 58 59 return driver_register(&drv->driver); 60 } 61 EXPORT_SYMBOL_GPL(nvmem_layout_driver_register); 62 63 void nvmem_layout_driver_unregister(struct nvmem_layout_driver *drv) 64 { 65 driver_unregister(&drv->driver); 66 } 67 EXPORT_SYMBOL_GPL(nvmem_layout_driver_unregister); 68 69 static void nvmem_layout_release_device(struct device *dev) 70 { 71 struct nvmem_layout *layout = to_nvmem_layout_device(dev); 72 73 of_node_put(layout->dev.of_node); 74 kfree(layout); 75 } 76 77 static int nvmem_layout_create_device(struct nvmem_device *nvmem, 78 struct device_node *np) 79 { 80 struct nvmem_layout *layout; 81 struct device *dev; 82 int ret; 83 84 layout = kzalloc(sizeof(*layout), GFP_KERNEL); 85 if (!layout) 86 return -ENOMEM; 87 88 /* Create a bidirectional link */ 89 layout->nvmem = nvmem; 90 nvmem->layout = layout; 91 92 /* Device model registration */ 93 dev = &layout->dev; 94 device_initialize(dev); 95 dev->parent = &nvmem->dev; 96 dev->bus = &nvmem_layout_bus_type; 97 dev->release = nvmem_layout_release_device; 98 dev->coherent_dma_mask = DMA_BIT_MASK(32); 99 dev->dma_mask = &dev->coherent_dma_mask; 100 device_set_node(dev, of_fwnode_handle(of_node_get(np))); 101 of_device_make_bus_id(dev); 102 of_msi_configure(dev, dev->of_node); 103 104 ret = device_add(dev); 105 if (ret) { 106 put_device(dev); 107 return ret; 108 } 109 110 return 0; 111 } 112 113 static const struct of_device_id of_nvmem_layout_skip_table[] = { 114 { .compatible = "fixed-layout", }, 115 {} 116 }; 117 118 static int nvmem_layout_bus_populate(struct nvmem_device *nvmem, 119 struct device_node *layout_dn) 120 { 121 int ret; 122 123 /* Make sure it has a compatible property */ 124 if (!of_get_property(layout_dn, "compatible", NULL)) { 125 pr_debug("%s() - skipping %pOF, no compatible prop\n", 126 __func__, layout_dn); 127 return 0; 128 } 129 130 /* Fixed layouts are parsed manually somewhere else for now */ 131 if (of_match_node(of_nvmem_layout_skip_table, layout_dn)) { 132 pr_debug("%s() - skipping %pOF node\n", __func__, layout_dn); 133 return 0; 134 } 135 136 if (of_node_check_flag(layout_dn, OF_POPULATED_BUS)) { 137 pr_debug("%s() - skipping %pOF, already populated\n", 138 __func__, layout_dn); 139 140 return 0; 141 } 142 143 /* NVMEM layout buses expect only a single device representing the layout */ 144 ret = nvmem_layout_create_device(nvmem, layout_dn); 145 if (ret) 146 return ret; 147 148 of_node_set_flag(layout_dn, OF_POPULATED_BUS); 149 150 return 0; 151 } 152 153 struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem) 154 { 155 return of_get_child_by_name(nvmem->dev.of_node, "nvmem-layout"); 156 } 157 EXPORT_SYMBOL_GPL(of_nvmem_layout_get_container); 158 159 /* 160 * Returns the number of devices populated, 0 if the operation was not relevant 161 * for this nvmem device, an error code otherwise. 162 */ 163 int nvmem_populate_layout(struct nvmem_device *nvmem) 164 { 165 struct device_node *layout_dn; 166 int ret; 167 168 layout_dn = of_nvmem_layout_get_container(nvmem); 169 if (!layout_dn) 170 return 0; 171 172 /* Populate the layout device */ 173 device_links_supplier_sync_state_pause(); 174 ret = nvmem_layout_bus_populate(nvmem, layout_dn); 175 device_links_supplier_sync_state_resume(); 176 177 of_node_put(layout_dn); 178 return ret; 179 } 180 181 void nvmem_destroy_layout(struct nvmem_device *nvmem) 182 { 183 struct device *dev; 184 185 if (!nvmem->layout) 186 return; 187 188 dev = &nvmem->layout->dev; 189 of_node_clear_flag(dev->of_node, OF_POPULATED_BUS); 190 device_unregister(dev); 191 } 192 193 int nvmem_layout_bus_register(void) 194 { 195 return bus_register(&nvmem_layout_bus_type); 196 } 197 198 void nvmem_layout_bus_unregister(void) 199 { 200 bus_unregister(&nvmem_layout_bus_type); 201 } 202