1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2022 Intel Corporation
4  */
5 
6 #include <drm/drm_device.h>
7 #include <linux/device.h>
8 #include <linux/kobject.h>
9 #include <linux/printk.h>
10 #include <linux/sysfs.h>
11 
12 #include "i915_drv.h"
13 #include "i915_sysfs.h"
14 #include "intel_gt.h"
15 #include "intel_gt_sysfs.h"
16 #include "intel_gt_sysfs_pm.h"
17 #include "intel_gt_types.h"
18 #include "intel_rc6.h"
19 
20 bool is_object_gt(struct kobject *kobj)
21 {
22 	return !strncmp(kobj->name, "gt", 2);
23 }
24 
25 static struct intel_gt *kobj_to_gt(struct kobject *kobj)
26 {
27 	return container_of(kobj, struct intel_gt, sysfs_gt);
28 }
29 
30 struct intel_gt *intel_gt_sysfs_get_drvdata(struct device *dev,
31 					    const char *name)
32 {
33 	struct kobject *kobj = &dev->kobj;
34 
35 	/*
36 	 * We are interested at knowing from where the interface
37 	 * has been called, whether it's called from gt/ or from
38 	 * the parent directory.
39 	 * From the interface position it depends also the value of
40 	 * the private data.
41 	 * If the interface is called from gt/ then private data is
42 	 * of the "struct intel_gt *" type, otherwise it's * a
43 	 * "struct drm_i915_private *" type.
44 	 */
45 	if (!is_object_gt(kobj)) {
46 		struct drm_i915_private *i915 = kdev_minor_to_i915(dev);
47 
48 		return to_gt(i915);
49 	}
50 
51 	return kobj_to_gt(kobj);
52 }
53 
54 static struct kobject *gt_get_parent_obj(struct intel_gt *gt)
55 {
56 	return &gt->i915->drm.primary->kdev->kobj;
57 }
58 
59 static ssize_t id_show(struct device *dev,
60 		       struct device_attribute *attr,
61 		       char *buf)
62 {
63 	struct intel_gt *gt = intel_gt_sysfs_get_drvdata(dev, attr->attr.name);
64 
65 	return sysfs_emit(buf, "%u\n", gt->info.id);
66 }
67 static DEVICE_ATTR_RO(id);
68 
69 static struct attribute *id_attrs[] = {
70 	&dev_attr_id.attr,
71 	NULL,
72 };
73 ATTRIBUTE_GROUPS(id);
74 
75 /* A kobject needs a release() method even if it does nothing */
76 static void kobj_gt_release(struct kobject *kobj)
77 {
78 }
79 
80 static struct kobj_type kobj_gt_type = {
81 	.release = kobj_gt_release,
82 	.sysfs_ops = &kobj_sysfs_ops,
83 	.default_groups = id_groups,
84 };
85 
86 void intel_gt_sysfs_register(struct intel_gt *gt)
87 {
88 	/*
89 	 * We need to make things right with the
90 	 * ABI compatibility. The files were originally
91 	 * generated under the parent directory.
92 	 *
93 	 * We generate the files only for gt 0
94 	 * to avoid duplicates.
95 	 */
96 	if (gt_is_root(gt))
97 		intel_gt_sysfs_pm_init(gt, gt_get_parent_obj(gt));
98 
99 	/* init and xfer ownership to sysfs tree */
100 	if (kobject_init_and_add(&gt->sysfs_gt, &kobj_gt_type,
101 				 gt->i915->sysfs_gt, "gt%d", gt->info.id))
102 		goto exit_fail;
103 
104 	intel_gt_sysfs_pm_init(gt, &gt->sysfs_gt);
105 
106 	return;
107 
108 exit_fail:
109 	kobject_put(&gt->sysfs_gt);
110 	drm_warn(&gt->i915->drm,
111 		 "failed to initialize gt%d sysfs root\n", gt->info.id);
112 }
113 
114 void intel_gt_sysfs_unregister(struct intel_gt *gt)
115 {
116 	kobject_put(&gt->sysfs_gt);
117 }
118