src/device/root_device.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <console/console.h>
   4 #include <device/device.h>
   5 #include <device/pci.h>
   6 #include <reset.h>
   7
   8 void enable_static_device(struct device *dev)
   9 {
  10         if (dev->chip_ops && dev->chip_ops->enable_dev)
  11                 dev->chip_ops->enable_dev(dev);
  12
  13         if (dev->ops && dev->ops->enable)
  14                 dev->ops->enable(dev);
  15
  16         printk(BIOS_DEBUG, "%s %s\n", dev_path(dev),
  17                dev->enabled ? "enabled" : "disabled");
  18 }
  19
  20 /**
  21  * Enable devices on static buses.
  22  *
  23  * The enumeration of certain buses is purely static. The existence of
  24  * devices on those buses can be completely determined at compile time
  25  * and is specified in the config file. Typical examples are the 'PNP'
  26  * devices on a legacy ISA/LPC bus. There is no need of probing of any kind,
  27  * the only thing we have to do is to walk through the bus and
  28  * enable or disable devices as indicated in the config file.
  29  *
  30  * On the other hand, some devices are virtual and their existence is
  31  * artificial. They can not be probed at run time. One example is the
  32  * debug device. Those virtual devices have to be listed in the config
  33  * file under some static bus in order to be enumerated at run time.
  34  *
  35  * @param bus Pointer to the device to which the static buses are attached to.
  36  */
  37
  38 void enable_static_devices(struct device *bus)
  39 {
  40         struct device *child;
  41
  42         if (!bus->downstream)
  43                 return;
  44
  45         for (child = bus->downstream->children; child; child = child->sibling)
  46                 enable_static_device(child);
  47 }
  48
  49 void scan_generic_bus(struct device *bus)
  50 {
  51         struct device *child;
  52         static int bus_max = 0;
  53
  54         printk(BIOS_SPEW, "%s for %s\n", __func__, dev_path(bus));
  55
  56         if (bus->downstream) {
  57                 bus->downstream->secondary = ++bus_max;
  58
  59                 for (child = bus->downstream->children; child; child = child->sibling) {
  60                         enable_static_device(child);
  61                         printk(BIOS_DEBUG, "bus: %s->", dev_path(child->upstream->dev));
  62                 }
  63         }
  64
  65         printk(BIOS_SPEW, "%s for %s done\n", __func__, dev_path(bus));
  66 }
  67
  68 void scan_smbus(struct device *bus)
  69 {
  70         scan_generic_bus(bus);
  71 }
  72
  73 /*
  74  * Default scan_bus() implementation
  75  *
  76  * This is the default implementation for buses that can't
  77  * be probed at runtime. It simply walks through the topology
  78  * given by the mainboard's `devicetree.cb`.
  79  *
  80  * First, all direct descendants of the given device are
  81  * enabled. Then, downstream buses are scanned.
  82  */
  83 void scan_static_bus(struct device *bus)
  84 {
  85         printk(BIOS_SPEW, "%s for %s\n", __func__, dev_path(bus));
  86
  87         enable_static_devices(bus);
  88
  89         if (bus->downstream)
  90                 scan_bridges(bus->downstream);
  91
  92         printk(BIOS_SPEW, "%s for %s done\n", __func__, dev_path(bus));
  93 }
  94
  95 static void root_dev_reset(struct bus *bus)
  96 {
  97         printk(BIOS_INFO, "Resetting board...\n");
  98         board_reset();
  99 }
 100
 101 #if CONFIG(HAVE_ACPI_TABLES)
 102 static const char *root_dev_acpi_name(const struct device *dev)
 103 {
 104         return "\\_SB";
 105 }
 106 #endif
 107
 108 /**
 109  * Default device operation for root device.
 110  *
 111  * This is the default device operation for root devices. These operations
 112  * should be fully usable as is. However the chip_operations::enable_dev()
 113  * of a motherboard can override this if you want non-default behavior.
 114  */
 115 struct device_operations default_dev_ops_root = {
 116         .read_resources   = noop_read_resources,
 117         .set_resources    = noop_set_resources,
 118         .scan_bus         = scan_static_bus,
 119         .reset_bus        = root_dev_reset,
 120 #if CONFIG(HAVE_ACPI_TABLES)
 121         .acpi_name        = root_dev_acpi_name,
 122 #endif
 123 };