pci: sandbox: Support dynamically binding device driver

At present all emulated sandbox pci devices must be present in the
device tree in order to be used. The real world pci uclass driver
supports pci device driver matching, and we should add such support
on sandbox too.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/doc/driver-model/pci-info.txt b/doc/driver-model/pci-info.txt
index 52b4389d2c..e1701d1fbc 100644
--- a/doc/driver-model/pci-info.txt
+++ b/doc/driver-model/pci-info.txt
@@ -133,3 +133,31 @@ When this bus is scanned we will end up with something like this:
 
 When accesses go to the pci@1f,0 device they are forwarded to its child, the
 emulator.
+
+The sandbox PCI drivers also support dynamic driver binding, allowing device
+driver to declare the driver binding information via U_BOOT_PCI_DEVICE(),
+eliminating the need to provide any device tree node under the host controller
+node. It is required a "sandbox,dev-info" property must be provided in the
+host controller node for this functionality to work.
+
+	pci1: pci-controller1 {
+		compatible = "sandbox,pci";
+		...
+		sandbox,dev-info = <0x08 0x00 0x1234 0x5678
+				    0x0c 0x00 0x1234 0x5678>;
+	};
+
+The "sandbox,dev-info" property specifies all dynamic PCI devices on this bus.
+Each dynamic PCI device is encoded as 4 cells a group. The first and second
+cells are PCI device number and function number respectively. The third and
+fourth cells are PCI vendor ID and device ID respectively.
+
+When this bus is scanned we will end up with something like this:
+
+ pci        [ + ]   pci_sandbo  |-- pci-controller1
+ pci_emul   [   ]   sandbox_sw  |   |-- sandbox_swap_case_emul
+ pci_emul   [   ]   sandbox_sw  |   `-- sandbox_swap_case_emul
+
+Note the difference from the statically declared device nodes is that the
+device is directly attached to the host controller, instead of via a container
+device like pci@1f,0.