sconfig: Allow to specify device operations

Currently we only have runtime mechanisms to assign device operations to
a node in our devicetree (with one exception: the root device). The most
common method is to map PCI IDs to the device operations with a `struct
pci_driver`. Another accustomed way is to let a chip driver assign them.

For very common drivers, e.g. those in soc/intel/common/blocks/, the PCI
ID lists grew very large and are incredibly error-prone. Often, IDs are
missing and sometimes IDs are added almost mechanically without checking
the code for compatibility. Maintaining these lists in a central place
also reduces flexibility.

Now, for onboard devices it is actually unnecessary to assign the device
operations at runtime. We already know exactly what operations should be
assigned. And since we are using chipset devicetrees, we have a perfect
place to put that information.

This patch adds a simple mechanism to `sconfig`. It allows us to speci-
fy operations per device, e.g.

  device pci 00.0 alias system_agent on
          ops system_agent_ops
  end

The operations are given as a C identifier. In this example, we simply
assume that a global `struct device_operations system_agent_ops` exists.

Change-Id: I2833d2f2450fde3206c33393f58b86fd4280b566
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66483
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

1 files changed, 10 insertions, 0 deletions

diff --git a/util/sconfig/sconfig.h b/util/sconfig/sconfig.h
index 5b50cc0158..c2a43af5cf 100644
--- a/util/sconfig/sconfig.h
+++ b/util/sconfig/sconfig.h
@@ -57,6 +57,11 @@ struct fw_config_probe {
 	struct fw_config_probe *next;
 };
 
+struct identifier {
+	const char *id;
+	struct identifier *next;
+};
+
 struct chip;
 struct chip_instance {
 	/* Monotonically increasing ID for each chip instance. */
@@ -165,6 +170,9 @@ struct device {
 	/* Pointer to last bus under this device. */
 	struct bus *last_bus;
 
+	/* Global identifier of the ops for this device. */
+	char *ops_id;
+
 	/* SMBIOS slot type */
 	char *smbios_slot_type;
 
@@ -236,3 +244,5 @@ void add_fw_config_probe(struct bus *bus, const char *field, const char *option)
 
 void append_fw_config_bits(struct fw_config_field_bits **bits,
 			   unsigned int start_bit, unsigned int end_bit);
+
+void add_device_ops(struct bus *, char *ops_id);