Infrastructure code providing APIs for managing leaf driver instance
groups, facilitating inter-leaf driver calls and root calls.

Signed-off-by: Sonal Santan <sonal.san...@xilinx.com>
Signed-off-by: Max Zhen <max.z...@xilinx.com>
Signed-off-by: Lizhi Hou <lizhi....@xilinx.com>
---
 drivers/fpga/xrt/lib/subdev.c | 865 ++++++++++++++++++++++++++++++++++
 1 file changed, 865 insertions(+)
 create mode 100644 drivers/fpga/xrt/lib/subdev.c

diff --git a/drivers/fpga/xrt/lib/subdev.c b/drivers/fpga/xrt/lib/subdev.c
new file mode 100644
index 000000000000..6428b183fee3
--- /dev/null
+++ b/drivers/fpga/xrt/lib/subdev.c
@@ -0,0 +1,865 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2021 Xilinx, Inc.
+ *
+ * Authors:
+ *     Cheng Zhen <m...@xilinx.com>
+ */
+
+#include <linux/platform_device.h>
+#include <linux/pci.h>
+#include <linux/vmalloc.h>
+#include "xleaf.h"
+#include "subdev_pool.h"
+#include "lib-drv.h"
+#include "metadata.h"
+
+#define IS_ROOT_DEV(dev) ((dev)->bus == &pci_bus_type)
+static inline struct device *find_root(struct platform_device *pdev)
+{
+       struct device *d = DEV(pdev);
+
+       while (!IS_ROOT_DEV(d))
+               d = d->parent;
+       return d;
+}
+
+/*
+ * It represents a holder of a subdev. One holder can repeatedly hold a subdev
+ * as long as there is a unhold corresponding to a hold.
+ */
+struct xrt_subdev_holder {
+       struct list_head xsh_holder_list;
+       struct device *xsh_holder;
+       int xsh_count;
+       struct kref xsh_kref;
+};
+
+/*
+ * It represents a specific instance of platform driver for a subdev, which
+ * provides services to its clients (another subdev driver or root driver).
+ */
+struct xrt_subdev {
+       struct list_head xs_dev_list;
+       struct list_head xs_holder_list;
+       enum xrt_subdev_id xs_id;               /* type of subdev */
+       struct platform_device *xs_pdev;        /* a particular subdev inst */
+       struct completion xs_holder_comp;
+};
+
+static struct xrt_subdev *xrt_subdev_alloc(void)
+{
+       struct xrt_subdev *sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
+
+       if (!sdev)
+               return NULL;
+
+       INIT_LIST_HEAD(&sdev->xs_dev_list);
+       INIT_LIST_HEAD(&sdev->xs_holder_list);
+       init_completion(&sdev->xs_holder_comp);
+       return sdev;
+}
+
+static void xrt_subdev_free(struct xrt_subdev *sdev)
+{
+       kfree(sdev);
+}
+
+int xrt_subdev_root_request(struct platform_device *self, u32 cmd, void *arg)
+{
+       struct device *dev = DEV(self);
+       struct xrt_subdev_platdata *pdata = DEV_PDATA(self);
+
+       WARN_ON(!pdata->xsp_root_cb);
+       return (*pdata->xsp_root_cb)(dev->parent, pdata->xsp_root_cb_arg, cmd, 
arg);
+}
+
+/*
+ * Subdev common sysfs nodes.
+ */
+static ssize_t holders_show(struct device *dev, struct device_attribute *attr, 
char *buf)
+{
+       ssize_t len;
+       struct platform_device *pdev = to_platform_device(dev);
+       struct xrt_root_get_holders holders = { pdev, buf, 1024 };
+
+       len = xrt_subdev_root_request(pdev, XRT_ROOT_GET_LEAF_HOLDERS, 
&holders);
+       if (len >= holders.xpigh_holder_buf_len)
+               return len;
+       buf[len] = '\n';
+       return len + 1;
+}
+static DEVICE_ATTR_RO(holders);
+
+static struct attribute *xrt_subdev_attrs[] = {
+       &dev_attr_holders.attr,
+       NULL,
+};
+
+static ssize_t metadata_output(struct file *filp, struct kobject *kobj,
+                              struct bin_attribute *attr, char *buf, loff_t 
off, size_t count)
+{
+       struct device *dev = kobj_to_dev(kobj);
+       struct platform_device *pdev = to_platform_device(dev);
+       struct xrt_subdev_platdata *pdata = DEV_PDATA(pdev);
+       unsigned char *blob;
+       unsigned long  size;
+       ssize_t ret = 0;
+
+       blob = pdata->xsp_dtb;
+       size = xrt_md_size(dev, blob);
+       if (size == XRT_MD_INVALID_LENGTH) {
+               ret = -EINVAL;
+               goto failed;
+       }
+
+       if (off >= size)
+               goto failed;
+
+       if (off + count > size)
+               count = size - off;
+       memcpy(buf, blob + off, count);
+
+       ret = count;
+failed:
+       return ret;
+}
+
+static struct bin_attribute meta_data_attr = {
+       .attr = {
+               .name = "metadata",
+               .mode = 0400
+       },
+       .read = metadata_output,
+       .size = 0
+};
+
+static struct bin_attribute  *xrt_subdev_bin_attrs[] = {
+       &meta_data_attr,
+       NULL,
+};
+
+static const struct attribute_group xrt_subdev_attrgroup = {
+       .attrs = xrt_subdev_attrs,
+       .bin_attrs = xrt_subdev_bin_attrs,
+};
+
+/*
+ * Given the device metadata, parse it to get IO ranges and construct
+ * resource array.
+ */
+static int
+xrt_subdev_getres(struct device *parent, enum xrt_subdev_id id,
+                 char *dtb, struct resource **res, int *res_num)
+{
+       struct xrt_subdev_platdata *pdata;
+       struct resource *pci_res = NULL;
+       const u64 *bar_range;
+       const u32 *bar_idx;
+       char *ep_name = NULL, *regmap = NULL;
+       uint bar;
+       int count1 = 0, count2 = 0, ret;
+
+       if (!dtb)
+               return -EINVAL;
+
+       pdata = DEV_PDATA(to_platform_device(parent));
+
+       /* go through metadata and count endpoints in it */
+       for (xrt_md_get_next_endpoint(parent, dtb, NULL, NULL, &ep_name, 
&regmap); ep_name;
+            xrt_md_get_next_endpoint(parent, dtb, ep_name, regmap, &ep_name, 
&regmap)) {
+               ret = xrt_md_get_prop(parent, dtb, ep_name, regmap,
+                                     XRT_MD_PROP_IO_OFFSET, (const void 
**)&bar_range, NULL);
+               if (!ret)
+                       count1++;
+       }
+       if (!count1)
+               return 0;
+
+       /* allocate resource array for all endpoints been found in metadata */
+       *res = vzalloc(sizeof(**res) * count1);
+
+       /* go through all endpoints again and get IO range for each endpoint */
+       for (xrt_md_get_next_endpoint(parent, dtb, NULL, NULL, &ep_name, 
&regmap); ep_name;
+            xrt_md_get_next_endpoint(parent, dtb, ep_name, regmap, &ep_name, 
&regmap)) {
+               ret = xrt_md_get_prop(parent, dtb, ep_name, regmap,
+                                     XRT_MD_PROP_IO_OFFSET, (const void 
**)&bar_range, NULL);
+               if (ret)
+                       continue;
+               xrt_md_get_prop(parent, dtb, ep_name, regmap,
+                               XRT_MD_PROP_BAR_IDX, (const void **)&bar_idx, 
NULL);
+               bar = bar_idx ? be32_to_cpu(*bar_idx) : 0;
+               xleaf_get_barres(to_platform_device(parent), &pci_res, bar);
+               (*res)[count2].start = pci_res->start +
+                       be64_to_cpu(bar_range[0]);
+               (*res)[count2].end = pci_res->start +
+                       be64_to_cpu(bar_range[0]) +
+                       be64_to_cpu(bar_range[1]) - 1;
+               (*res)[count2].flags = IORESOURCE_MEM;
+               /* check if there is conflicted resource */
+               ret = request_resource(pci_res, *res + count2);
+               if (ret) {
+                       dev_err(parent, "Conflict resource %pR\n", *res + 
count2);
+                       vfree(*res);
+                       *res_num = 0;
+                       *res = NULL;
+                       return ret;
+               }
+               release_resource(*res + count2);
+
+               (*res)[count2].parent = pci_res;
+
+               xrt_md_find_endpoint(parent, pdata->xsp_dtb, ep_name,
+                                    regmap, &(*res)[count2].name);
+
+               count2++;
+       }
+
+       WARN_ON(count1 != count2);
+       *res_num = count2;
+
+       return 0;
+}
+
+static inline enum xrt_subdev_file_mode
+xleaf_devnode_mode(struct xrt_subdev_drvdata *drvdata)
+{
+       return drvdata->xsd_file_ops.xsf_mode;
+}
+
+static bool xrt_subdev_cdev_auto_creation(struct platform_device *pdev)
+{
+       struct xrt_subdev_drvdata *drvdata = DEV_DRVDATA(pdev);
+       enum xrt_subdev_file_mode mode = xleaf_devnode_mode(drvdata);
+
+       if (!drvdata)
+               return false;
+
+       if (!xleaf_devnode_enabled(drvdata))
+               return false;
+
+       return (mode == XRT_SUBDEV_FILE_DEFAULT || mode == 
XRT_SUBDEV_FILE_MULTI_INST);
+}
+
+static struct xrt_subdev *
+xrt_subdev_create(struct device *parent, enum xrt_subdev_id id,
+                 xrt_subdev_root_cb_t pcb, void *pcb_arg, char *dtb)
+{
+       struct xrt_subdev_platdata *pdata = NULL;
+       struct platform_device *pdev = NULL;
+       int inst = PLATFORM_DEVID_NONE;
+       struct xrt_subdev *sdev = NULL;
+       struct resource *res = NULL;
+       unsigned long dtb_len = 0;
+       int res_num = 0;
+       size_t pdata_sz;
+       int ret;
+
+       sdev = xrt_subdev_alloc();
+       if (!sdev) {
+               dev_err(parent, "failed to alloc subdev for ID %d", id);
+               goto fail;
+       }
+       sdev->xs_id = id;
+
+       if (!dtb) {
+               ret = xrt_md_create(parent, &dtb);
+               if (ret) {
+                       dev_err(parent, "can't create empty dtb: %d", ret);
+                       goto fail;
+               }
+       }
+       xrt_md_pack(parent, dtb);
+       dtb_len = xrt_md_size(parent, dtb);
+       if (dtb_len == XRT_MD_INVALID_LENGTH) {
+               dev_err(parent, "invalid metadata len %ld", dtb_len);
+               goto fail;
+       }
+       pdata_sz = sizeof(struct xrt_subdev_platdata) + dtb_len;
+
+       /* Prepare platform data passed to subdev. */
+       pdata = vzalloc(pdata_sz);
+       if (!pdata)
+               goto fail;
+
+       pdata->xsp_root_cb = pcb;
+       pdata->xsp_root_cb_arg = pcb_arg;
+       memcpy(pdata->xsp_dtb, dtb, dtb_len);
+       if (id == XRT_SUBDEV_GRP) {
+               /* Group can only be created by root driver. */
+               pdata->xsp_root_name = dev_name(parent);
+       } else {
+               struct platform_device *grp = to_platform_device(parent);
+               /* Leaf can only be created by group driver. */
+               WARN_ON(strncmp(xrt_drv_name(XRT_SUBDEV_GRP),
+                               platform_get_device_id(grp)->name,
+                               strlen(xrt_drv_name(XRT_SUBDEV_GRP)) + 1));
+               pdata->xsp_root_name = DEV_PDATA(grp)->xsp_root_name;
+       }
+
+       /* Obtain dev instance number. */
+       inst = xrt_drv_get_instance(id);
+       if (inst < 0) {
+               dev_err(parent, "failed to obtain instance: %d", inst);
+               goto fail;
+       }
+
+       /* Create subdev. */
+       if (id != XRT_SUBDEV_GRP) {
+               int rc = xrt_subdev_getres(parent, id, dtb, &res, &res_num);
+
+               if (rc) {
+                       dev_err(parent, "failed to get resource for %s.%d: %d",
+                               xrt_drv_name(id), inst, rc);
+                       goto fail;
+               }
+       }
+       pdev = platform_device_register_resndata(parent, xrt_drv_name(id),
+                                                inst, res, res_num, pdata, 
pdata_sz);
+       vfree(res);
+       if (IS_ERR(pdev)) {
+               dev_err(parent, "failed to create subdev for %s inst %d: %ld",
+                       xrt_drv_name(id), inst, PTR_ERR(pdev));
+               goto fail;
+       }
+       sdev->xs_pdev = pdev;
+
+       if (device_attach(DEV(pdev)) != 1) {
+               xrt_err(pdev, "failed to attach");
+               goto fail;
+       }
+
+       if (sysfs_create_group(&DEV(pdev)->kobj, &xrt_subdev_attrgroup))
+               xrt_err(pdev, "failed to create sysfs group");
+
+       /*
+        * Create sysfs sym link under root for leaves
+        * under random groups for easy access to them.
+        */
+       if (id != XRT_SUBDEV_GRP) {
+               if (sysfs_create_link(&find_root(pdev)->kobj,
+                                     &DEV(pdev)->kobj, dev_name(DEV(pdev)))) {
+                       xrt_err(pdev, "failed to create sysfs link");
+               }
+       }
+
+       /* All done, ready to handle req thru cdev. */
+       if (xrt_subdev_cdev_auto_creation(pdev))
+               xleaf_devnode_create(pdev, 
DEV_DRVDATA(pdev)->xsd_file_ops.xsf_dev_name, NULL);
+
+       vfree(pdata);
+       return sdev;
+
+fail:
+       vfree(pdata);
+       if (sdev && !IS_ERR_OR_NULL(sdev->xs_pdev))
+               platform_device_unregister(sdev->xs_pdev);
+       if (inst >= 0)
+               xrt_drv_put_instance(id, inst);
+       xrt_subdev_free(sdev);
+       return NULL;
+}
+
+static void xrt_subdev_destroy(struct xrt_subdev *sdev)
+{
+       struct platform_device *pdev = sdev->xs_pdev;
+       struct device *dev = DEV(pdev);
+       int inst = pdev->id;
+       int ret;
+
+       /* Take down the device node */
+       if (xrt_subdev_cdev_auto_creation(pdev)) {
+               ret = xleaf_devnode_destroy(pdev);
+               WARN_ON(ret);
+       }
+       if (sdev->xs_id != XRT_SUBDEV_GRP)
+               sysfs_remove_link(&find_root(pdev)->kobj, dev_name(dev));
+       sysfs_remove_group(&dev->kobj, &xrt_subdev_attrgroup);
+       platform_device_unregister(pdev);
+       xrt_drv_put_instance(sdev->xs_id, inst);
+       xrt_subdev_free(sdev);
+}
+
+struct platform_device *
+xleaf_get_leaf(struct platform_device *pdev, xrt_subdev_match_t match_cb, void 
*match_arg)
+{
+       int rc;
+       struct xrt_root_get_leaf get_leaf = {
+               pdev, match_cb, match_arg, };
+
+       rc = xrt_subdev_root_request(pdev, XRT_ROOT_GET_LEAF, &get_leaf);
+       if (rc)
+               return NULL;
+       return get_leaf.xpigl_tgt_pdev;
+}
+EXPORT_SYMBOL_GPL(xleaf_get_leaf);
+
+bool xleaf_has_endpoint(struct platform_device *pdev, const char 
*endpoint_name)
+{
+       struct resource *res;
+       int i = 0;
+
+       do {
+               res = platform_get_resource(pdev, IORESOURCE_MEM, i);
+               if (res && !strncmp(res->name, endpoint_name, strlen(res->name) 
+ 1))
+                       return true;
+               ++i;
+       } while (res);
+
+       return false;
+}
+EXPORT_SYMBOL_GPL(xleaf_has_endpoint);
+
+int xleaf_put_leaf(struct platform_device *pdev, struct platform_device *leaf)
+{
+       struct xrt_root_put_leaf put_leaf = { pdev, leaf };
+
+       return xrt_subdev_root_request(pdev, XRT_ROOT_PUT_LEAF, &put_leaf);
+}
+EXPORT_SYMBOL_GPL(xleaf_put_leaf);
+
+int xleaf_create_group(struct platform_device *pdev, char *dtb)
+{
+       return xrt_subdev_root_request(pdev, XRT_ROOT_CREATE_GROUP, dtb);
+}
+EXPORT_SYMBOL_GPL(xleaf_create_group);
+
+int xleaf_destroy_group(struct platform_device *pdev, int instance)
+{
+       return xrt_subdev_root_request(pdev, XRT_ROOT_REMOVE_GROUP, (void 
*)(uintptr_t)instance);
+}
+EXPORT_SYMBOL_GPL(xleaf_destroy_group);
+
+int xleaf_wait_for_group_bringup(struct platform_device *pdev)
+{
+       return xrt_subdev_root_request(pdev, XRT_ROOT_WAIT_GROUP_BRINGUP, NULL);
+}
+EXPORT_SYMBOL_GPL(xleaf_wait_for_group_bringup);
+
+static ssize_t
+xrt_subdev_get_holders(struct xrt_subdev *sdev, char *buf, size_t len)
+{
+       const struct list_head *ptr;
+       struct xrt_subdev_holder *h;
+       ssize_t n = 0;
+
+       list_for_each(ptr, &sdev->xs_holder_list) {
+               h = list_entry(ptr, struct xrt_subdev_holder, xsh_holder_list);
+               n += snprintf(buf + n, len - n, "%s:%d ",
+                             dev_name(h->xsh_holder), kref_read(&h->xsh_kref));
+               if (n >= (len - 1))
+                       break;
+       }
+       return n;
+}
+
+void xrt_subdev_pool_init(struct device *dev, struct xrt_subdev_pool *spool)
+{
+       INIT_LIST_HEAD(&spool->xsp_dev_list);
+       spool->xsp_owner = dev;
+       mutex_init(&spool->xsp_lock);
+       spool->xsp_closing = false;
+}
+
+static void xrt_subdev_free_holder(struct xrt_subdev_holder *holder)
+{
+       list_del(&holder->xsh_holder_list);
+       vfree(holder);
+}
+
+static void xrt_subdev_pool_wait_for_holders(struct xrt_subdev_pool *spool, 
struct xrt_subdev *sdev)
+{
+       const struct list_head *ptr, *next;
+       char holders[128];
+       struct xrt_subdev_holder *holder;
+       struct mutex *lk = &spool->xsp_lock;
+
+       while (!list_empty(&sdev->xs_holder_list)) {
+               int rc;
+
+               /* It's most likely a bug if we ever enters this loop. */
+               xrt_subdev_get_holders(sdev, holders, sizeof(holders));
+               xrt_err(sdev->xs_pdev, "awaits holders: %s", holders);
+               mutex_unlock(lk);
+               rc = wait_for_completion_killable(&sdev->xs_holder_comp);
+               mutex_lock(lk);
+               if (rc == -ERESTARTSYS) {
+                       xrt_err(sdev->xs_pdev, "give up on waiting for holders, 
clean up now");
+                       list_for_each_safe(ptr, next, &sdev->xs_holder_list) {
+                               holder = list_entry(ptr, struct 
xrt_subdev_holder, xsh_holder_list);
+                               xrt_subdev_free_holder(holder);
+                       }
+               }
+       }
+}
+
+void xrt_subdev_pool_fini(struct xrt_subdev_pool *spool)
+{
+       struct list_head *dl = &spool->xsp_dev_list;
+       struct mutex *lk = &spool->xsp_lock;
+
+       mutex_lock(lk);
+       if (spool->xsp_closing) {
+               mutex_unlock(lk);
+               return;
+       }
+       spool->xsp_closing = true;
+       mutex_unlock(lk);
+
+       /* Remove subdev in the reverse order of added. */
+       while (!list_empty(dl)) {
+               struct xrt_subdev *sdev = list_first_entry(dl, struct 
xrt_subdev, xs_dev_list);
+
+               xrt_subdev_pool_wait_for_holders(spool, sdev);
+               list_del(&sdev->xs_dev_list);
+               xrt_subdev_destroy(sdev);
+       }
+}
+
+static struct xrt_subdev_holder *xrt_subdev_find_holder(struct xrt_subdev 
*sdev,
+                                                       struct device 
*holder_dev)
+{
+       struct list_head *hl = &sdev->xs_holder_list;
+       struct xrt_subdev_holder *holder;
+       const struct list_head *ptr;
+
+       list_for_each(ptr, hl) {
+               holder = list_entry(ptr, struct xrt_subdev_holder, 
xsh_holder_list);
+               if (holder->xsh_holder == holder_dev)
+                       return holder;
+       }
+       return NULL;
+}
+
+static int xrt_subdev_hold(struct xrt_subdev *sdev, struct device *holder_dev)
+{
+       struct xrt_subdev_holder *holder = xrt_subdev_find_holder(sdev, 
holder_dev);
+       struct list_head *hl = &sdev->xs_holder_list;
+
+       if (!holder) {
+               holder = vzalloc(sizeof(*holder));
+               if (!holder)
+                       return -ENOMEM;
+               holder->xsh_holder = holder_dev;
+               kref_init(&holder->xsh_kref);
+               list_add_tail(&holder->xsh_holder_list, hl);
+       } else {
+               kref_get(&holder->xsh_kref);
+       }
+
+       return 0;
+}
+
+static void xrt_subdev_free_holder_kref(struct kref *kref)
+{
+       struct xrt_subdev_holder *holder = container_of(kref, struct 
xrt_subdev_holder, xsh_kref);
+
+       xrt_subdev_free_holder(holder);
+}
+
+static int
+xrt_subdev_release(struct xrt_subdev *sdev, struct device *holder_dev)
+{
+       struct xrt_subdev_holder *holder = xrt_subdev_find_holder(sdev, 
holder_dev);
+       struct list_head *hl = &sdev->xs_holder_list;
+
+       if (!holder) {
+               dev_err(holder_dev, "can't release, %s did not hold %s",
+                       dev_name(holder_dev), dev_name(DEV(sdev->xs_pdev)));
+               return -EINVAL;
+       }
+       kref_put(&holder->xsh_kref, xrt_subdev_free_holder_kref);
+
+       /* kref_put above may remove holder from list. */
+       if (list_empty(hl))
+               complete(&sdev->xs_holder_comp);
+       return 0;
+}
+
+int xrt_subdev_pool_add(struct xrt_subdev_pool *spool, enum xrt_subdev_id id,
+                       xrt_subdev_root_cb_t pcb, void *pcb_arg, char *dtb)
+{
+       struct mutex *lk = &spool->xsp_lock;
+       struct list_head *dl = &spool->xsp_dev_list;
+       struct xrt_subdev *sdev;
+       int ret = 0;
+
+       sdev = xrt_subdev_create(spool->xsp_owner, id, pcb, pcb_arg, dtb);
+       if (sdev) {
+               mutex_lock(lk);
+               if (spool->xsp_closing) {
+                       /* No new subdev when pool is going away. */
+                       xrt_err(sdev->xs_pdev, "pool is closing");
+                       ret = -ENODEV;
+               } else {
+                       list_add(&sdev->xs_dev_list, dl);
+               }
+               mutex_unlock(lk);
+               if (ret)
+                       xrt_subdev_destroy(sdev);
+       } else {
+               ret = -EINVAL;
+       }
+
+       ret = ret ? ret : sdev->xs_pdev->id;
+       return ret;
+}
+
+int xrt_subdev_pool_del(struct xrt_subdev_pool *spool, enum xrt_subdev_id id, 
int instance)
+{
+       const struct list_head *ptr;
+       struct mutex *lk = &spool->xsp_lock;
+       struct list_head *dl = &spool->xsp_dev_list;
+       struct xrt_subdev *sdev;
+       int ret = -ENOENT;
+
+       mutex_lock(lk);
+       if (spool->xsp_closing) {
+               /* Pool is going away, all subdevs will be gone. */
+               mutex_unlock(lk);
+               return 0;
+       }
+       list_for_each(ptr, dl) {
+               sdev = list_entry(ptr, struct xrt_subdev, xs_dev_list);
+               if (sdev->xs_id != id || sdev->xs_pdev->id != instance)
+                       continue;
+               xrt_subdev_pool_wait_for_holders(spool, sdev);
+               list_del(&sdev->xs_dev_list);
+               ret = 0;
+               break;
+       }
+       mutex_unlock(lk);
+       if (ret)
+               return ret;
+
+       xrt_subdev_destroy(sdev);
+       return 0;
+}
+
+static int xrt_subdev_pool_get_impl(struct xrt_subdev_pool *spool, 
xrt_subdev_match_t match,
+                                   void *arg, struct device *holder_dev, 
struct xrt_subdev **sdevp)
+{
+       struct platform_device *pdev = (struct platform_device *)arg;
+       struct list_head *dl = &spool->xsp_dev_list;
+       struct mutex *lk = &spool->xsp_lock;
+       struct xrt_subdev *sdev = NULL;
+       const struct list_head *ptr;
+       struct xrt_subdev *d = NULL;
+       int ret = -ENOENT;
+
+       mutex_lock(lk);
+
+       if (!pdev) {
+               if (match == XRT_SUBDEV_MATCH_PREV) {
+                       sdev = list_empty(dl) ? NULL :
+                               list_last_entry(dl, struct xrt_subdev, 
xs_dev_list);
+               } else if (match == XRT_SUBDEV_MATCH_NEXT) {
+                       sdev = list_first_entry_or_null(dl, struct xrt_subdev, 
xs_dev_list);
+               }
+       }
+
+       list_for_each(ptr, dl) {
+               d = list_entry(ptr, struct xrt_subdev, xs_dev_list);
+               if (match == XRT_SUBDEV_MATCH_PREV || match == 
XRT_SUBDEV_MATCH_NEXT) {
+                       if (d->xs_pdev != pdev)
+                               continue;
+               } else {
+                       if (!match(d->xs_id, d->xs_pdev, arg))
+                               continue;
+               }
+
+               if (match == XRT_SUBDEV_MATCH_PREV)
+                       sdev = !list_is_first(ptr, dl) ? list_prev_entry(d, 
xs_dev_list) : NULL;
+               else if (match == XRT_SUBDEV_MATCH_NEXT)
+                       sdev = !list_is_last(ptr, dl) ? list_next_entry(d, 
xs_dev_list) : NULL;
+               else
+                       sdev = d;
+       }
+
+       if (sdev)
+               ret = xrt_subdev_hold(sdev, holder_dev);
+
+       mutex_unlock(lk);
+
+       if (!ret)
+               *sdevp = sdev;
+       return ret;
+}
+
+int xrt_subdev_pool_get(struct xrt_subdev_pool *spool, xrt_subdev_match_t 
match, void *arg,
+                       struct device *holder_dev, struct platform_device 
**pdevp)
+{
+       int rc;
+       struct xrt_subdev *sdev;
+
+       rc = xrt_subdev_pool_get_impl(spool, match, arg, holder_dev, &sdev);
+       if (rc) {
+               if (rc != -ENOENT)
+                       dev_err(holder_dev, "failed to hold device: %d", rc);
+               return rc;
+       }
+
+       if (!IS_ROOT_DEV(holder_dev)) {
+               xrt_dbg(to_platform_device(holder_dev), "%s <<==== %s",
+                       dev_name(holder_dev), dev_name(DEV(sdev->xs_pdev)));
+       }
+
+       *pdevp = sdev->xs_pdev;
+       return 0;
+}
+
+static int xrt_subdev_pool_put_impl(struct xrt_subdev_pool *spool, struct 
platform_device *pdev,
+                                   struct device *holder_dev)
+{
+       const struct list_head *ptr;
+       struct mutex *lk = &spool->xsp_lock;
+       struct list_head *dl = &spool->xsp_dev_list;
+       struct xrt_subdev *sdev;
+       int ret = -ENOENT;
+
+       mutex_lock(lk);
+       list_for_each(ptr, dl) {
+               sdev = list_entry(ptr, struct xrt_subdev, xs_dev_list);
+               if (sdev->xs_pdev != pdev)
+                       continue;
+               ret = xrt_subdev_release(sdev, holder_dev);
+               break;
+       }
+       mutex_unlock(lk);
+
+       return ret;
+}
+
+int xrt_subdev_pool_put(struct xrt_subdev_pool *spool, struct platform_device 
*pdev,
+                       struct device *holder_dev)
+{
+       int ret = xrt_subdev_pool_put_impl(spool, pdev, holder_dev);
+
+       if (ret)
+               return ret;
+
+       if (!IS_ROOT_DEV(holder_dev)) {
+               xrt_dbg(to_platform_device(holder_dev), "%s <<==X== %s",
+                       dev_name(holder_dev), dev_name(DEV(pdev)));
+       }
+       return 0;
+}
+
+void xrt_subdev_pool_trigger_event(struct xrt_subdev_pool *spool, enum 
xrt_events e)
+{
+       struct platform_device *tgt = NULL;
+       struct xrt_subdev *sdev = NULL;
+       struct xrt_event evt;
+
+       while (!xrt_subdev_pool_get_impl(spool, XRT_SUBDEV_MATCH_NEXT,
+                                        tgt, spool->xsp_owner, &sdev)) {
+               tgt = sdev->xs_pdev;
+               evt.xe_evt = e;
+               evt.xe_subdev.xevt_subdev_id = sdev->xs_id;
+               evt.xe_subdev.xevt_subdev_instance = tgt->id;
+               xrt_subdev_root_request(tgt, XRT_ROOT_EVENT_SYNC, &evt);
+               xrt_subdev_pool_put_impl(spool, tgt, spool->xsp_owner);
+       }
+}
+
+void xrt_subdev_pool_handle_event(struct xrt_subdev_pool *spool, struct 
xrt_event *evt)
+{
+       struct platform_device *tgt = NULL;
+       struct xrt_subdev *sdev = NULL;
+
+       while (!xrt_subdev_pool_get_impl(spool, XRT_SUBDEV_MATCH_NEXT,
+                                        tgt, spool->xsp_owner, &sdev)) {
+               tgt = sdev->xs_pdev;
+               xleaf_call(tgt, XRT_XLEAF_EVENT, evt);
+               xrt_subdev_pool_put_impl(spool, tgt, spool->xsp_owner);
+       }
+}
+
+ssize_t xrt_subdev_pool_get_holders(struct xrt_subdev_pool *spool,
+                                   struct platform_device *pdev, char *buf, 
size_t len)
+{
+       const struct list_head *ptr;
+       struct mutex *lk = &spool->xsp_lock;
+       struct list_head *dl = &spool->xsp_dev_list;
+       struct xrt_subdev *sdev;
+       ssize_t ret = 0;
+
+       mutex_lock(lk);
+       list_for_each(ptr, dl) {
+               sdev = list_entry(ptr, struct xrt_subdev, xs_dev_list);
+               if (sdev->xs_pdev != pdev)
+                       continue;
+               ret = xrt_subdev_get_holders(sdev, buf, len);
+               break;
+       }
+       mutex_unlock(lk);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(xrt_subdev_pool_get_holders);
+
+int xleaf_broadcast_event(struct platform_device *pdev, enum xrt_events evt, 
bool async)
+{
+       struct xrt_event e = { evt, };
+       enum xrt_root_cmd cmd = async ? XRT_ROOT_EVENT_ASYNC : 
XRT_ROOT_EVENT_SYNC;
+
+       WARN_ON(evt == XRT_EVENT_POST_CREATION || evt == XRT_EVENT_PRE_REMOVAL);
+       return xrt_subdev_root_request(pdev, cmd, &e);
+}
+EXPORT_SYMBOL_GPL(xleaf_broadcast_event);
+
+void xleaf_hot_reset(struct platform_device *pdev)
+{
+       xrt_subdev_root_request(pdev, XRT_ROOT_HOT_RESET, NULL);
+}
+EXPORT_SYMBOL_GPL(xleaf_hot_reset);
+
+void xleaf_get_barres(struct platform_device *pdev, struct resource **res, 
uint bar_idx)
+{
+       struct xrt_root_get_res arg = { 0 };
+
+       if (bar_idx > PCI_STD_RESOURCE_END) {
+               xrt_err(pdev, "Invalid bar idx %d", bar_idx);
+               *res = NULL;
+               return;
+       }
+
+       xrt_subdev_root_request(pdev, XRT_ROOT_GET_RESOURCE, &arg);
+
+       *res = &arg.xpigr_res[bar_idx];
+}
+
+void xleaf_get_root_id(struct platform_device *pdev, unsigned short *vendor, 
unsigned short *device,
+                      unsigned short *subvendor, unsigned short *subdevice)
+{
+       struct xrt_root_get_id id = { 0 };
+
+       WARN_ON(!vendor && !device && !subvendor && !subdevice);
+
+       xrt_subdev_root_request(pdev, XRT_ROOT_GET_ID, (void *)&id);
+       if (vendor)
+               *vendor = id.xpigi_vendor_id;
+       if (device)
+               *device = id.xpigi_device_id;
+       if (subvendor)
+               *subvendor = id.xpigi_sub_vendor_id;
+       if (subdevice)
+               *subdevice = id.xpigi_sub_device_id;
+}
+
+struct device *xleaf_register_hwmon(struct platform_device *pdev, const char 
*name, void *drvdata,
+                                   const struct attribute_group **grps)
+{
+       struct xrt_root_hwmon hm = { true, name, drvdata, grps, };
+
+       xrt_subdev_root_request(pdev, XRT_ROOT_HWMON, (void *)&hm);
+       return hm.xpih_hwmon_dev;
+}
+
+void xleaf_unregister_hwmon(struct platform_device *pdev, struct device *hwmon)
+{
+       struct xrt_root_hwmon hm = { false, };
+
+       hm.xpih_hwmon_dev = hwmon;
+       xrt_subdev_root_request(pdev, XRT_ROOT_HWMON, (void *)&hm);
+}
-- 
2.27.0

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