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         struct bus *link;
  42
  43         for (link = bus->link_list; link; link = link->next) {
  44                 for (child = link->children; child; child = child->sibling) {
  45                         enable_static_device(child);
  46                 }
  47         }
  48 }
  49
  50 void scan_generic_bus(struct device *bus)
  51 {
  52         struct device *child;
  53         struct bus *link;
  54         static int bus_max = 0;
  55
  56         printk(BIOS_SPEW, "%s for %s\n", __func__, dev_path(bus));
  57
  58         for (link = bus->link_list; link; link = link->next) {
  59
  60                 link->secondary = ++bus_max;
  61
  62                 for (child = link->children; child; child = child->sibling) {
  63                         enable_static_device(child);
  64                         printk(BIOS_DEBUG, "bus: %s[%d]->", dev_path(child->bus->dev),
  65                                child->bus->link_num);
  66                 }
  67         }
  68
  69         printk(BIOS_SPEW, "%s for %s done\n", __func__, dev_path(bus));
  70 }
  71
  72 void scan_smbus(struct device *bus)
  73 {
  74         scan_generic_bus(bus);
  75 }
  76
  77 /*
  78  * Default scan_bus() implementation
  79  *
  80  * This is the default implementation for buses that can't
  81  * be probed at runtime. It simply walks through the topology
  82  * given by the mainboard's `devicetree.cb`.
  83  *
  84  * First, all direct descendants of the given device are
  85  * enabled. Then, downstream buses are scanned.
  86  */
  87 void scan_static_bus(struct device *bus)
  88 {
  89         struct bus *link;
  90
  91         printk(BIOS_SPEW, "%s for %s\n", __func__, dev_path(bus));
  92
  93         enable_static_devices(bus);
  94
  95         for (link = bus->link_list; link; link = link->next)
  96                 scan_bridges(link);
  97
  98         printk(BIOS_SPEW, "%s for %s done\n", __func__, dev_path(bus));
  99 }
 100
 101 static void root_dev_reset(struct bus *bus)
 102 {
 103         printk(BIOS_INFO, "Resetting board...\n");
 104         board_reset();
 105 }
 106
 107 #if CONFIG(HAVE_ACPI_TABLES)
 108 static const char *root_dev_acpi_name(const struct device *dev)
 109 {
 110         return "\\_SB";
 111 }
 112 #endif
 113
 114 /**
 115  * Default device operation for root device.
 116  *
 117  * This is the default device operation for root devices. These operations
 118  * should be fully usable as is. However the chip_operations::enable_dev()
 119  * of a motherboard can override this if you want non-default behavior.
 120  */
 121 struct device_operations default_dev_ops_root = {
 122         .read_resources   = noop_read_resources,
 123         .set_resources    = noop_set_resources,
 124         .scan_bus         = scan_static_bus,
 125         .reset_bus        = root_dev_reset,
 126 #if CONFIG(HAVE_ACPI_TABLES)
 127         .acpi_name        = root_dev_acpi_name,
 128 #endif
 129 };