drivers/nvmem/layouts.c

   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 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 }