[PATCH V6 XRT Alveo 05/20] fpga: xrt: group driver

[Lizhi Hou]

group driver that manages life cycle of a bunch of leaf driver instances
and bridges them with root.

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/group.h |  25 +++
 drivers/fpga/xrt/lib/group.c     | 278 +++++++++++++++++++++++++++++++
 2 files changed, 303 insertions(+)
 create mode 100644 drivers/fpga/xrt/include/group.h
 create mode 100644 drivers/fpga/xrt/lib/group.c

diff --git a/drivers/fpga/xrt/include/group.h b/drivers/fpga/xrt/include/group.h
new file mode 100644
index 000000000000..09e9d03f53fe
--- /dev/null
+++ b/drivers/fpga/xrt/include/group.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2021 Xilinx, Inc.
+ *
+ * Authors:
+ *	Cheng Zhen <maxz@xxxxxxxxxx>
+ */
+
+#ifndef _XRT_GROUP_H_
+#define _XRT_GROUP_H_
+
+#include "xleaf.h"
+
+/*
+ * Group driver leaf calls.
+ */
+enum xrt_group_leaf_cmd {
+	XRT_GROUP_GET_LEAF = XRT_XLEAF_CUSTOM_BASE, /* See comments in xleaf.h */
+	XRT_GROUP_PUT_LEAF,
+	XRT_GROUP_INIT_CHILDREN,
+	XRT_GROUP_FINI_CHILDREN,
+	XRT_GROUP_TRIGGER_EVENT,
+};
+
+#endif	/* _XRT_GROUP_H_ */
diff --git a/drivers/fpga/xrt/lib/group.c b/drivers/fpga/xrt/lib/group.c
new file mode 100644
index 000000000000..b45f05449e0b
--- /dev/null
+++ b/drivers/fpga/xrt/lib/group.c
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx Alveo FPGA Group Driver
+ *
+ * Copyright (C) 2020-2021 Xilinx, Inc.
+ *
+ * Authors:
+ *	Cheng Zhen <maxz@xxxxxxxxxx>
+ */
+
+#include <linux/mod_devicetable.h>
+#include "xleaf.h"
+#include "subdev_pool.h"
+#include "group.h"
+#include "metadata.h"
+#include "lib-drv.h"
+
+#define XRT_GRP "xrt_group"
+
+struct xrt_group {
+	struct xrt_device *xdev;
+	struct xrt_subdev_pool leaves;
+	bool leaves_created;
+	struct mutex lock; /* lock for group */
+};
+
+static int xrt_grp_root_cb(struct device *dev, void *parg,
+			   enum xrt_root_cmd cmd, void *arg)
+{
+	int rc;
+	struct xrt_device *xdev =
+		container_of(dev, struct xrt_device, dev);
+	struct xrt_group *xg = (struct xrt_group *)parg;
+
+	switch (cmd) {
+	case XRT_ROOT_GET_LEAF_HOLDERS: {
+		struct xrt_root_get_holders *holders =
+			(struct xrt_root_get_holders *)arg;
+		rc = xrt_subdev_pool_get_holders(&xg->leaves,
+						 holders->xpigh_xdev,
+						 holders->xpigh_holder_buf,
+						 holders->xpigh_holder_buf_len);
+		break;
+	}
+	default:
+		/* Forward parent call to root. */
+		rc = xrt_subdev_root_request(xdev, cmd, arg);
+		break;
+	}
+
+	return rc;
+}
+
+/*
+ * Cut subdev's dtb from group's dtb based on passed-in endpoint descriptor.
+ * Return the subdev's dtb through dtbp, if found.
+ */
+static int xrt_grp_cut_subdev_dtb(struct xrt_group *xg, struct xrt_dev_endpoints *eps,
+				  char *grp_dtb, char **dtbp)
+{
+	int ret, i, ep_count = 0;
+	char *dtb = NULL;
+
+	ret = xrt_md_create(DEV(xg->xdev), &dtb);
+	if (ret)
+		return ret;
+
+	for (i = 0; eps->xse_names[i].ep_name || eps->xse_names[i].compat; i++) {
+		const char *ep_name = eps->xse_names[i].ep_name;
+		const char *compat = eps->xse_names[i].compat;
+
+		if (!ep_name)
+			xrt_md_get_compatible_endpoint(DEV(xg->xdev), grp_dtb, compat, &ep_name);
+		if (!ep_name)
+			continue;
+
+		ret = xrt_md_copy_endpoint(DEV(xg->xdev), dtb, grp_dtb, ep_name, compat, NULL);
+		if (ret)
+			continue;
+		xrt_md_del_endpoint(DEV(xg->xdev), grp_dtb, ep_name, compat);
+		ep_count++;
+	}
+	/* Found enough endpoints, return the subdev's dtb. */
+	if (ep_count >= eps->xse_min_ep) {
+		*dtbp = dtb;
+		return 0;
+	}
+
+	/* Cleanup - Restore all endpoints that has been deleted, if any. */
+	if (ep_count > 0) {
+		xrt_md_copy_endpoint(DEV(xg->xdev), grp_dtb, dtb,
+				     XRT_MD_NODE_ENDPOINTS, NULL, NULL);
+	}
+	vfree(dtb);
+	*dtbp = NULL;
+	return 0;
+}
+
+static int xrt_grp_create_leaves(struct xrt_group *xg)
+{
+	struct xrt_subdev_platdata *pdata = DEV_PDATA(xg->xdev);
+	struct xrt_dev_endpoints *eps = NULL;
+	int ret = 0, failed = 0;
+	enum xrt_subdev_id did;
+	char *grp_dtb = NULL;
+	unsigned long mlen;
+
+	if (!pdata)
+		return -EINVAL;
+
+	mlen = xrt_md_size(DEV(xg->xdev), pdata->xsp_dtb);
+	if (mlen == XRT_MD_INVALID_LENGTH) {
+		xrt_err(xg->xdev, "invalid dtb, len %ld", mlen);
+		return -EINVAL;
+	}
+
+	mutex_lock(&xg->lock);
+
+	if (xg->leaves_created) {
+		/*
+		 * This is expected since caller does not keep track of the state of the group
+		 * and may, in some cases, still try to create leaves after it has already been
+		 * created. This special error code will let the caller know what is going on.
+		 */
+		mutex_unlock(&xg->lock);
+		return -EEXIST;
+	}
+
+	grp_dtb = vmalloc(mlen);
+	if (!grp_dtb) {
+		mutex_unlock(&xg->lock);
+		return -ENOMEM;
+	}
+
+	/* Create all leaves based on dtb. */
+	xrt_info(xg->xdev, "bringing up leaves...");
+	memcpy(grp_dtb, pdata->xsp_dtb, mlen);
+	for (did = 0; did < XRT_SUBDEV_NUM; did++) {
+		eps = xrt_drv_get_endpoints(did);
+		while (eps && eps->xse_names) {
+			char *dtb = NULL;
+
+			ret = xrt_grp_cut_subdev_dtb(xg, eps, grp_dtb, &dtb);
+			if (ret) {
+				failed++;
+				xrt_err(xg->xdev, "failed to cut subdev dtb for drv %s: %d",
+					xrt_drv_name(did), ret);
+			}
+			if (!dtb) {
+				/*
+				 * No more dtb to cut or bad things happened for this instance,
+				 * switch to the next one.
+				 */
+				eps++;
+				continue;
+			}
+
+			/* Found a dtb for this instance, let's add it. */
+			ret = xrt_subdev_pool_add(&xg->leaves, did, xrt_grp_root_cb, xg, dtb);
+			if (ret < 0) {
+				/*
+				 * It is not a fatal error here. Some functionality is not usable
+				 * due to this missing device, but the error can be handled
+				 * when the functionality is used.
+				 */
+				failed++;
+				xrt_err(xg->xdev, "failed to add %s: %d", xrt_drv_name(did), ret);
+			}
+			vfree(dtb);
+			/* Continue searching for the same instance from grp_dtb. */
+		}
+	}
+
+	xg->leaves_created = true;
+	vfree(grp_dtb);
+	mutex_unlock(&xg->lock);
+	return failed == 0 ? 0 : -ECHILD;
+}
+
+static void xrt_grp_remove_leaves(struct xrt_group *xg)
+{
+	mutex_lock(&xg->lock);
+
+	if (!xg->leaves_created) {
+		mutex_unlock(&xg->lock);
+		return;
+	}
+
+	xrt_info(xg->xdev, "tearing down leaves...");
+	xrt_subdev_pool_fini(&xg->leaves);
+	xg->leaves_created = false;
+
+	mutex_unlock(&xg->lock);
+}
+
+static int xrt_grp_probe(struct xrt_device *xdev)
+{
+	struct xrt_group *xg;
+
+	xrt_info(xdev, "probing...");
+
+	xg = devm_kzalloc(&xdev->dev, sizeof(*xg), GFP_KERNEL);
+	if (!xg)
+		return -ENOMEM;
+
+	xg->xdev = xdev;
+	mutex_init(&xg->lock);
+	xrt_subdev_pool_init(DEV(xdev), &xg->leaves);
+	xrt_set_drvdata(xdev, xg);
+
+	return 0;
+}
+
+static void xrt_grp_remove(struct xrt_device *xdev)
+{
+	struct xrt_group *xg = xrt_get_drvdata(xdev);
+
+	xrt_info(xdev, "leaving...");
+	xrt_grp_remove_leaves(xg);
+}
+
+static int xrt_grp_leaf_call(struct xrt_device *xdev, u32 cmd, void *arg)
+{
+	int rc = 0;
+	struct xrt_group *xg = xrt_get_drvdata(xdev);
+
+	switch (cmd) {
+	case XRT_XLEAF_EVENT:
+		/* Simply forward to every child. */
+		xrt_subdev_pool_handle_event(&xg->leaves,
+					     (struct xrt_event *)arg);
+		break;
+	case XRT_GROUP_GET_LEAF: {
+		struct xrt_root_get_leaf *get_leaf =
+			(struct xrt_root_get_leaf *)arg;
+
+		rc = xrt_subdev_pool_get(&xg->leaves, get_leaf->xpigl_match_cb,
+					 get_leaf->xpigl_match_arg,
+					 DEV(get_leaf->xpigl_caller_xdev),
+					 &get_leaf->xpigl_tgt_xdev);
+		break;
+	}
+	case XRT_GROUP_PUT_LEAF: {
+		struct xrt_root_put_leaf *put_leaf =
+			(struct xrt_root_put_leaf *)arg;
+
+		rc = xrt_subdev_pool_put(&xg->leaves, put_leaf->xpipl_tgt_xdev,
+					 DEV(put_leaf->xpipl_caller_xdev));
+		break;
+	}
+	case XRT_GROUP_INIT_CHILDREN:
+		rc = xrt_grp_create_leaves(xg);
+		break;
+	case XRT_GROUP_FINI_CHILDREN:
+		xrt_grp_remove_leaves(xg);
+		break;
+	case XRT_GROUP_TRIGGER_EVENT:
+		xrt_subdev_pool_trigger_event(&xg->leaves, (enum xrt_events)(uintptr_t)arg);
+		break;
+	default:
+		xrt_err(xdev, "unknown IOCTL cmd %d", cmd);
+		rc = -EINVAL;
+		break;
+	}
+	return rc;
+}
+
+static struct xrt_driver xrt_group_driver = {
+	.driver	= {
+		.name    = XRT_GRP,
+	},
+	.subdev_id = XRT_SUBDEV_GRP,
+	.probe = xrt_grp_probe,
+	.remove = xrt_grp_remove,
+	.leaf_call = xrt_grp_leaf_call,
+};
+
+XRT_LEAF_INIT_FINI_FUNC(group);
-- 
2.27.0