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>

5 files changed, 295 insertions, 0 deletions

diff --git a/drivers/axi/Kconfig b/drivers/axi/Kconfig
index ae80c98af8..f81d843f89 100644
--- a/drivers/axi/Kconfig
+++ b/drivers/axi/Kconfig
@@ -22,4 +22,11 @@ config IHS_AXI
 	  Interface (IHS AXI) bus on a gdsys IHS FPGA used to communicate with
 	  IP cores in the FPGA (e.g. video transmitter cores).
 
+config AXI_SANDBOX
+	bool "Enable AXI sandbox driver"
+	depends on DM
+	help
+	  Support AXI (Advanced eXtensible Interface) emulation for the sandbox
+	  environment.
+
 endif
diff --git a/drivers/axi/Makefile b/drivers/axi/Makefile
index 18d9380e9b..66b6c5a28f 100644
--- a/drivers/axi/Makefile
+++ b/drivers/axi/Makefile
@@ -7,3 +7,6 @@
 
 obj-$(CONFIG_AXI) += axi-uclass.o
 obj-$(CONFIG_IHS_AXI) += ihs_axi.o
+obj-$(CONFIG_SANDBOX) += axi-emul-uclass.o
+obj-$(CONFIG_SANDBOX) += sandbox_store.o
+obj-$(CONFIG_AXI_SANDBOX) += axi_sandbox.o
diff --git a/drivers/axi/axi-emul-uclass.c b/drivers/axi/axi-emul-uclass.c
new file mode 100644
index 0000000000..06c42006ee
--- /dev/null
+++ b/drivers/axi/axi-emul-uclass.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2018
+ * Mario Six, Guntermann & Drunck GmbH, mario.six@gdsys.cc
+ */
+
+#include <common.h>
+#include <axi.h>
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <asm/axi.h>
+
+int axi_sandbox_get_emul(struct udevice *bus, ulong address,
+			 enum axi_size_t size, struct udevice **emulp)
+{
+	struct udevice *dev;
+	u32 reg[2];
+	uint offset;
+
+	switch (size) {
+	case AXI_SIZE_8:
+		offset = 1;
+		break;
+	case AXI_SIZE_16:
+		offset = 2;
+		break;
+	case AXI_SIZE_32:
+		offset = 4;
+		break;
+	default:
+		debug("%s: Unknown AXI transfer size '%d'", bus->name, size);
+		offset = 0;
+	}
+
+	/*
+	 * Note: device_find_* don't activate the devices; they're activated
+	 *	 as-needed below.
+	 */
+	for (device_find_first_child(bus, &dev);
+	     dev;
+	     device_find_next_child(&dev)) {
+		int ret;
+
+		ret = dev_read_u32_array(dev, "reg", reg, ARRAY_SIZE(reg));
+		if (ret) {
+			debug("%s: Could not read 'reg' property of %s\n",
+			      bus->name, dev->name);
+			continue;
+		}
+
+		/*
+		 * Does the transfer's address fall into this device's address
+		 * space?
+		 */
+		if (address >= reg[0] && address <= reg[0] + reg[1] - offset) {
+			/* If yes, activate it... */
+			if (device_probe(dev)) {
+				debug("%s: Could not activate %s\n",
+				      bus->name, dev->name);
+				return -ENODEV;
+			}
+
+			/* ...and return it */
+			*emulp = dev;
+			return 0;
+		}
+	}
+
+	return -ENODEV;
+}
+
+int axi_get_store(struct udevice *dev, u8 **storep)
+{
+	struct axi_emul_ops *ops = axi_emul_get_ops(dev);
+
+	if (!ops->get_store)
+		return -ENOSYS;
+
+	return ops->get_store(dev, storep);
+}
+
+UCLASS_DRIVER(axi_emul) = {
+	.id		= UCLASS_AXI_EMUL,
+	.name		= "axi_emul",
+};
diff --git a/drivers/axi/axi_sandbox.c b/drivers/axi/axi_sandbox.c
new file mode 100644
index 0000000000..b91c91f6b3
--- /dev/null
+++ b/drivers/axi/axi_sandbox.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2018
+ * Mario Six, Guntermann & Drunck GmbH, mario.six@gdsys.cc
+ */
+
+#include <common.h>
+#include <axi.h>
+#include <dm.h>
+#include <asm/axi.h>
+
+/*
+ * This driver implements a AXI bus for the sandbox architecture for testing
+ * purposes.
+ *
+ * The bus forwards every access to it to a special AXI emulation device (which
+ * it gets via the axi_emul_get_ops function) that implements a simple
+ * read/write storage.
+ *
+ * The emulator device must still be contained in the device tree in the usual
+ * way, since configuration data for the storage is read from the DT.
+ */
+
+static int axi_sandbox_read(struct udevice *bus, ulong address, void *data,
+			    enum axi_size_t size)
+{
+	struct axi_emul_ops *ops;
+	struct udevice *emul;
+	int ret;
+
+	/* Get emulator device */
+	ret = axi_sandbox_get_emul(bus, address, size, &emul);
+	if (ret)
+		return ret == -ENODEV ? 0 : ret;
+	/* Forward all reads to the AXI emulator */
+	ops = axi_emul_get_ops(emul);
+	if (!ops || !ops->read)
+		return -ENOSYS;
+
+	return ops->read(emul, address, data, size);
+}
+
+static int axi_sandbox_write(struct udevice *bus, ulong address, void *data,
+			     enum axi_size_t size)
+{
+	struct axi_emul_ops *ops;
+	struct udevice *emul;
+	int ret;
+
+	/* Get emulator device */
+	ret = axi_sandbox_get_emul(bus, address, size, &emul);
+	if (ret)
+		return ret == -ENODEV ? 0 : ret;
+	/* Forward all writes to the AXI emulator */
+	ops = axi_emul_get_ops(emul);
+	if (!ops || !ops->write)
+		return -ENOSYS;
+
+	return ops->write(emul, address, data, size);
+}
+
+static const struct udevice_id axi_sandbox_ids[] = {
+	{ .compatible = "sandbox,axi" },
+	{ /* sentinel */ }
+};
+
+static const struct axi_ops axi_sandbox_ops = {
+	.read = axi_sandbox_read,
+	.write = axi_sandbox_write,
+};
+
+U_BOOT_DRIVER(axi_sandbox_bus) = {
+	.name           = "axi_sandbox_bus",
+	.id             = UCLASS_AXI,
+	.of_match       = axi_sandbox_ids,
+	.ops		= &axi_sandbox_ops,
+};
diff --git a/drivers/axi/sandbox_store.c b/drivers/axi/sandbox_store.c
new file mode 100644
index 0000000000..d724f19079
--- /dev/null
+++ b/drivers/axi/sandbox_store.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2018
+ * Mario Six, Guntermann & Drunck GmbH, mario.six@gdsys.cc
+ */
+
+#include <common.h>
+#include <axi.h>
+#include <dm.h>
+
+/**
+ * struct sandbox_store_priv - Private data structure of a AXI store device
+ * @store: The buffer holding the device's internal memory, which is read from
+ *	   and written to using the driver's methods
+ */
+struct sandbox_store_priv {
+	u8 *store;
+};
+
+/**
+ * copy_axi_data() - Copy data from source to destination with a given AXI
+ *		     transfer width
+ * @src:  Pointer to the data source from where data will be read
+ * @dst:  Pointer to the data destination where data will be written to
+ * @size: Size of the data to be copied given by a axi_size_t enum value
+ *
+ * Return: 0 if OK, -ve on error
+ */
+static int copy_axi_data(void *src, void *dst, enum axi_size_t size)
+{
+	switch (size) {
+	case AXI_SIZE_8:
+		*((u8 *)dst) = *((u8 *)src);
+		return 0;
+	case AXI_SIZE_16:
+		*((u16 *)dst) = be16_to_cpu(*((u16 *)src));
+		return 0;
+	case AXI_SIZE_32:
+		*((u32 *)dst) = be32_to_cpu(*((u32 *)src));
+		return 0;
+	default:
+		debug("%s: Unknown AXI transfer size '%d'\n", __func__, size);
+		return -EINVAL;
+	}
+}
+
+static int sandbox_store_read(struct udevice *dev, ulong address, void *data,
+			      enum axi_size_t size)
+{
+	struct sandbox_store_priv *priv = dev_get_priv(dev);
+
+	return copy_axi_data(priv->store + address, data, size);
+}
+
+static int sandbox_store_write(struct udevice *dev, ulong address, void *data,
+			       enum axi_size_t size)
+{
+	struct sandbox_store_priv *priv = dev_get_priv(dev);
+
+	return copy_axi_data(data, priv->store + address, size);
+}
+
+static int sandbox_store_get_store(struct udevice *dev, u8 **store)
+{
+	struct sandbox_store_priv *priv = dev_get_priv(dev);
+
+	*store = priv->store;
+
+	return 0;
+}
+
+static const struct udevice_id sandbox_store_ids[] = {
+	{ .compatible = "sandbox,sandbox_store" },
+	{ /* sentinel */ }
+};
+
+static const struct axi_emul_ops sandbox_store_ops = {
+	.read = sandbox_store_read,
+	.write = sandbox_store_write,
+	.get_store = sandbox_store_get_store,
+};
+
+static int sandbox_store_probe(struct udevice *dev)
+{
+	struct sandbox_store_priv *priv = dev_get_priv(dev);
+	u32 reg[2];
+	int ret;
+
+	ret = dev_read_u32_array(dev, "reg", reg, ARRAY_SIZE(reg));
+	if (ret) {
+		debug("%s: Could not read 'reg' property\n", dev->name);
+		return -EINVAL;
+	}
+
+	/*
+	 * Allocate the device's internal storage that will be read
+	 * from/written to
+	 */
+	priv->store = calloc(reg[1], 1);
+	if (!priv->store)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int sandbox_store_remove(struct udevice *dev)
+{
+	struct sandbox_store_priv *priv = dev_get_priv(dev);
+
+	free(priv->store);
+
+	return 0;
+}
+
+U_BOOT_DRIVER(sandbox_axi_store) = {
+	.name           = "sandbox_axi_store",
+	.id             = UCLASS_AXI_EMUL,
+	.of_match       = sandbox_store_ids,
+	.ops		= &sandbox_store_ops,
+	.priv_auto_alloc_size = sizeof(struct sandbox_store_priv),
+	.probe          = sandbox_store_probe,
+	.remove		= sandbox_store_remove,
+};