axi: Add AXI sandbox driver and simple emulator

Add test infrastructure and tests for the AXI uclass.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Mario Six <mario.six@gdsys.cc>

1 files changed, 66 insertions, 0 deletions

diff --git a/arch/sandbox/include/asm/axi.h b/arch/sandbox/include/asm/axi.h
new file mode 100644
index 00000000000..d483f7b65a0
--- /dev/null
+++ b/arch/sandbox/include/asm/axi.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * (C) Copyright 2018
+ * Mario Six, Guntermann & Drunck GmbH, mario.six@gdsys.cc
+ */
+
+#ifndef __asm_axi_h
+#define __asm_axi_h
+
+#define axi_emul_get_ops(dev)	((struct axi_emul_ops *)(dev)->driver->ops)
+
+/**
+ * axi_sandbox_get_emul() - Retrieve a pointer to a AXI emulation device
+ * @bus:     The AXI bus from which to retrieve a emulation device
+ * @address: The address of a transfer that should be handled by a emulation
+ *	     device
+ * @length:  The data width of a transfer that should be handled by a emulation
+ *	     device
+ * @emulp:   Pointer to a buffer receiving the emulation device that handles
+ *	     the transfer specified by the address and length parameters
+ *
+ * To test the AXI uclass, we implement a simple AXI emulation device, which is
+ * a virtual device on a AXI bus that exposes a simple storage interface: When
+ * reading and writing from the device, the addresses are translated to offsets
+ * within the device's storage. For write accesses the data is written to the
+ * specified storage offset, and for read accesses the data is read from the
+ * specified storage offset.
+ *
+ * A DTS entry might look like this:
+ *
+ * axi: axi@0 {
+ *	compatible = "sandbox,axi";
+ *	#address-cells = <0x1>;
+ *	#size-cells = <0x1>;
+ *	store@0 {
+ *		compatible = "sandbox,sandbox_store";
+ *		reg = <0x0 0x400>;
+ *	};
+ * };
+ *
+ * This function may then be used to retrieve the pointer to the sandbox_store
+ * emulation device given the AXI bus device, and the data (address, data
+ * width) of a AXI transfer which should be handled by a emulation device.
+ *
+ * Return: 0 of OK, -ENODEV if no device capable of handling the specified
+ *	   transfer exists or the device could not be retrieved
+ */
+int axi_sandbox_get_emul(struct udevice *bus, ulong address, uint length,
+			 struct udevice **emulp);
+/**
+ * axi_get_store() - Get address of internal storage of a emulated AXI device
+ * @dev:	Emulated AXI device to get the pointer of the internal storage
+ *		for.
+ * @storep:	Pointer to the internal storage of the emulated AXI device.
+ *
+ * To preset or read back the contents internal storage of the emulated AXI
+ * device, this function returns the pointer to the storage. Changes to the
+ * contents of the storage are reflected when using the AXI read/write API
+ * methods, and vice versa, so by using this method expected read data can be
+ * set up in advance, and written data can be checked in unit tests.
+ *
+ * Return: 0 if OK, -ve on error.
+ */
+int axi_get_store(struct udevice *dev, u8 **storep);
+
+#endif /* __asm_axi_h */