[PATCH V7 XRT Alveo 19/20] fpga: xrt: partition isolation driver

[Lizhi Hou]

Add partition isolation xrt driver. partition isolation is
a hardware function discovered by walking firmware metadata.
A xrt device node will be created for it. Partition isolation
function isolate the different fpga regions

Signed-off-by: Sonal Santan <sonal.santan@xxxxxxxxxx>
Signed-off-by: Max Zhen <max.zhen@xxxxxxxxxx>
Signed-off-by: Lizhi Hou <lizhi.hou@xxxxxxxxxx>
Reviewed-by: Tom Rix <trix@xxxxxxxxxx>
---
 drivers/fpga/xrt/include/xleaf/axigate.h |  23 ++
 drivers/fpga/xrt/lib/xleaf/axigate.c     | 325 +++++++++++++++++++++++
 2 files changed, 348 insertions(+)
 create mode 100644 drivers/fpga/xrt/include/xleaf/axigate.h
 create mode 100644 drivers/fpga/xrt/lib/xleaf/axigate.c

diff --git a/drivers/fpga/xrt/include/xleaf/axigate.h b/drivers/fpga/xrt/include/xleaf/axigate.h
new file mode 100644
index 000000000000..58f32c76dca1
--- /dev/null
+++ b/drivers/fpga/xrt/include/xleaf/axigate.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2021 Xilinx, Inc.
+ *
+ * Authors:
+ *	Lizhi Hou <Lizhi.Hou@xxxxxxxxxx>
+ */
+
+#ifndef _XRT_AXIGATE_H_
+#define _XRT_AXIGATE_H_
+
+#include "xleaf.h"
+#include "metadata.h"
+
+/*
+ * AXIGATE driver leaf calls.
+ */
+enum xrt_axigate_leaf_cmd {
+	XRT_AXIGATE_CLOSE = XRT_XLEAF_CUSTOM_BASE, /* See comments in xleaf.h */
+	XRT_AXIGATE_OPEN,
+};
+
+#endif	/* _XRT_AXIGATE_H_ */
diff --git a/drivers/fpga/xrt/lib/xleaf/axigate.c b/drivers/fpga/xrt/lib/xleaf/axigate.c
new file mode 100644
index 000000000000..493707b782e4
--- /dev/null
+++ b/drivers/fpga/xrt/lib/xleaf/axigate.c
@@ -0,0 +1,325 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx Alveo FPGA AXI Gate Driver
+ *
+ * Copyright (C) 2020-2021 Xilinx, Inc.
+ *
+ * Authors:
+ *      Lizhi Hou<Lizhi.Hou@xxxxxxxxxx>
+ */
+
+#include <linux/mod_devicetable.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/regmap.h>
+#include <linux/io.h>
+#include "metadata.h"
+#include "xleaf.h"
+#include "xleaf/axigate.h"
+
+#define XRT_AXIGATE "xrt_axigate"
+
+#define XRT_AXIGATE_WRITE_REG		0
+#define XRT_AXIGATE_READ_REG		8
+
+#define XRT_AXIGATE_CTRL_CLOSE		0
+#define XRT_AXIGATE_CTRL_OPEN_BIT0	1
+#define XRT_AXIGATE_CTRL_OPEN_BIT1	2
+
+#define XRT_AXIGATE_INTERVAL		500 /* ns */
+
+struct xrt_axigate {
+	struct xrt_device	*xdev;
+	struct regmap		*regmap;
+	struct mutex		gate_lock; /* gate dev lock */
+	void			*evt_hdl;
+	const char		*ep_name;
+	bool			gate_closed;
+};
+
+XRT_DEFINE_REGMAP_CONFIG(axigate_regmap_config);
+
+/* the ep names are in the order of hardware layers */
+static const char * const xrt_axigate_epnames[] = {
+	XRT_MD_NODE_GATE_PLP, /* PLP: Provider Logic Partition */
+	XRT_MD_NODE_GATE_ULP  /* ULP: User Logic Partition */
+};
+
+static inline int close_gate(struct xrt_axigate *gate)
+{
+	u32 val;
+	int ret;
+
+	ret = regmap_write(gate->regmap, XRT_AXIGATE_WRITE_REG, XRT_AXIGATE_CTRL_CLOSE);
+	if (ret) {
+		xrt_err(gate->xdev, "write gate failed %d", ret);
+		return ret;
+	}
+	ndelay(XRT_AXIGATE_INTERVAL);
+	/*
+	 * Legacy hardware requires extra read work properly.
+	 * This is not on critical path, thus the extra read should not impact performance much.
+	 */
+	ret = regmap_read(gate->regmap, XRT_AXIGATE_READ_REG, &val);
+	if (ret) {
+		xrt_err(gate->xdev, "read gate failed %d", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static inline int open_gate(struct xrt_axigate *gate)
+{
+	u32 val;
+	int ret;
+
+	ret = regmap_write(gate->regmap, XRT_AXIGATE_WRITE_REG, XRT_AXIGATE_CTRL_OPEN_BIT1);
+	if (ret) {
+		xrt_err(gate->xdev, "write 2 failed %d", ret);
+		return ret;
+	}
+	ndelay(XRT_AXIGATE_INTERVAL);
+	/*
+	 * Legacy hardware requires extra read work properly.
+	 * This is not on critical path, thus the extra read should not impact performance much.
+	 */
+	ret = regmap_read(gate->regmap, XRT_AXIGATE_READ_REG, &val);
+	if (ret) {
+		xrt_err(gate->xdev, "read 2 failed %d", ret);
+		return ret;
+	}
+	ret = regmap_write(gate->regmap, XRT_AXIGATE_WRITE_REG,
+			   XRT_AXIGATE_CTRL_OPEN_BIT0 | XRT_AXIGATE_CTRL_OPEN_BIT1);
+	if (ret) {
+		xrt_err(gate->xdev, "write 3 failed %d", ret);
+		return ret;
+	}
+	ndelay(XRT_AXIGATE_INTERVAL);
+	ret = regmap_read(gate->regmap, XRT_AXIGATE_READ_REG, &val);
+	if (ret) {
+		xrt_err(gate->xdev, "read 3 failed %d", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int xrt_axigate_epname_idx(struct xrt_device *xdev)
+{
+	struct resource	*res;
+	int ret, i;
+
+	res = xrt_get_resource(xdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		xrt_err(xdev, "Empty Resource!");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(xrt_axigate_epnames); i++) {
+		ret = strncmp(xrt_axigate_epnames[i], res->name,
+			      strlen(xrt_axigate_epnames[i]) + 1);
+		if (!ret)
+			return i;
+	}
+
+	return -EINVAL;
+}
+
+static int xrt_axigate_close(struct xrt_device *xdev)
+{
+	struct xrt_axigate *gate;
+	u32 status = 0;
+	int ret;
+
+	gate = xrt_get_drvdata(xdev);
+
+	mutex_lock(&gate->gate_lock);
+	ret = regmap_read(gate->regmap, XRT_AXIGATE_READ_REG, &status);
+	if (ret) {
+		xrt_err(xdev, "read gate failed %d", ret);
+		goto failed;
+	}
+	if (status) {		/* gate is opened */
+		xleaf_broadcast_event(xdev, XRT_EVENT_PRE_GATE_CLOSE, false);
+		ret = close_gate(gate);
+		if (ret)
+			goto failed;
+	}
+
+	gate->gate_closed = true;
+
+failed:
+	mutex_unlock(&gate->gate_lock);
+
+	xrt_info(xdev, "close gate %s", gate->ep_name);
+	return ret;
+}
+
+static int xrt_axigate_open(struct xrt_device *xdev)
+{
+	struct xrt_axigate *gate;
+	u32 status;
+	int ret;
+
+	gate = xrt_get_drvdata(xdev);
+
+	mutex_lock(&gate->gate_lock);
+	ret = regmap_read(gate->regmap, XRT_AXIGATE_READ_REG, &status);
+	if (ret) {
+		xrt_err(xdev, "read gate failed %d", ret);
+		goto failed;
+	}
+	if (!status) {		/* gate is closed */
+		ret = open_gate(gate);
+		if (ret)
+			goto failed;
+		xleaf_broadcast_event(xdev, XRT_EVENT_POST_GATE_OPEN, true);
+		/* xrt_axigate_open() could be called in event cb, thus
+		 * we can not wait for the completes
+		 */
+	}
+
+	gate->gate_closed = false;
+
+failed:
+	mutex_unlock(&gate->gate_lock);
+
+	xrt_info(xdev, "open gate %s", gate->ep_name);
+	return ret;
+}
+
+static void xrt_axigate_event_cb(struct xrt_device *xdev, void *arg)
+{
+	struct xrt_axigate *gate = xrt_get_drvdata(xdev);
+	struct xrt_event *evt = (struct xrt_event *)arg;
+	enum xrt_events e = evt->xe_evt;
+	struct xrt_device *leaf;
+	enum xrt_subdev_id id;
+	struct resource	*res;
+	int instance;
+
+	if (e != XRT_EVENT_POST_CREATION)
+		return;
+
+	instance = evt->xe_subdev.xevt_subdev_instance;
+	id = evt->xe_subdev.xevt_subdev_id;
+	if (id != XRT_SUBDEV_AXIGATE)
+		return;
+
+	leaf = xleaf_get_leaf_by_id(xdev, id, instance);
+	if (!leaf)
+		return;
+
+	res = xrt_get_resource(leaf, IORESOURCE_MEM, 0);
+	if (!res || !strncmp(res->name, gate->ep_name, strlen(res->name) + 1)) {
+		xleaf_put_leaf(xdev, leaf);
+		return;
+	}
+
+	/* higher level axigate instance created, make sure the gate is opened. */
+	if (xrt_axigate_epname_idx(leaf) > xrt_axigate_epname_idx(xdev))
+		xrt_axigate_open(xdev);
+	else
+		xleaf_call(leaf, XRT_AXIGATE_OPEN, NULL);
+
+	xleaf_put_leaf(xdev, leaf);
+}
+
+static int
+xrt_axigate_leaf_call(struct xrt_device *xdev, u32 cmd, void *arg)
+{
+	int ret = 0;
+
+	switch (cmd) {
+	case XRT_XLEAF_EVENT:
+		xrt_axigate_event_cb(xdev, arg);
+		break;
+	case XRT_AXIGATE_CLOSE:
+		ret = xrt_axigate_close(xdev);
+		break;
+	case XRT_AXIGATE_OPEN:
+		ret = xrt_axigate_open(xdev);
+		break;
+	default:
+		xrt_err(xdev, "unsupported cmd %d", cmd);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int xrt_axigate_probe(struct xrt_device *xdev)
+{
+	struct xrt_axigate *gate = NULL;
+	void __iomem *base = NULL;
+	struct resource *res;
+	int ret;
+
+	gate = devm_kzalloc(&xdev->dev, sizeof(*gate), GFP_KERNEL);
+	if (!gate)
+		return -ENOMEM;
+
+	gate->xdev = xdev;
+	xrt_set_drvdata(xdev, gate);
+
+	xrt_info(xdev, "probing...");
+	res = xrt_get_resource(xdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		xrt_err(xdev, "Empty resource 0");
+		ret = -EINVAL;
+		goto failed;
+	}
+
+	base = devm_ioremap_resource(&xdev->dev, res);
+	if (IS_ERR(base)) {
+		xrt_err(xdev, "map base iomem failed");
+		ret = PTR_ERR(base);
+		goto failed;
+	}
+
+	gate->regmap = devm_regmap_init_mmio(&xdev->dev, base, &axigate_regmap_config);
+	if (IS_ERR(gate->regmap)) {
+		xrt_err(xdev, "regmap %pR failed", res);
+		ret = PTR_ERR(gate->regmap);
+		goto failed;
+	}
+	gate->ep_name = res->name;
+
+	mutex_init(&gate->gate_lock);
+
+	return 0;
+
+failed:
+	return ret;
+}
+
+static struct xrt_dev_endpoints xrt_axigate_endpoints[] = {
+	{
+		.xse_names = (struct xrt_dev_ep_names[]) {
+			{ .ep_name = XRT_MD_NODE_GATE_ULP },
+			{ NULL },
+		},
+		.xse_min_ep = 1,
+	},
+	{
+		.xse_names = (struct xrt_dev_ep_names[]) {
+			{ .ep_name = XRT_MD_NODE_GATE_PLP },
+			{ NULL },
+		},
+		.xse_min_ep = 1,
+	},
+	{ 0 },
+};
+
+static struct xrt_driver xrt_axigate_driver = {
+	.driver = {
+		.name = XRT_AXIGATE,
+	},
+	.subdev_id = XRT_SUBDEV_AXIGATE,
+	.endpoints = xrt_axigate_endpoints,
+	.probe = xrt_axigate_probe,
+	.leaf_call = xrt_axigate_leaf_call,
+};
+
+XRT_LEAF_INIT_FINI_FUNC(axigate);
-- 
2.27.0