1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2021 Microsoft
4  */
5 
6 #include <linux/efi.h>
7 #include <linux/hyperv.h>
8 #include <linux/module.h>
9 #include <linux/pci.h>
10 #include <linux/screen_info.h>
11 
12 #include <drm/drm_aperture.h>
13 #include <drm/drm_atomic_helper.h>
14 #include <drm/drm_drv.h>
15 #include <drm/drm_fbdev_generic.h>
16 #include <drm/drm_gem_shmem_helper.h>
17 #include <drm/drm_simple_kms_helper.h>
18 
19 #include "hyperv_drm.h"
20 
21 #define DRIVER_NAME "hyperv_drm"
22 #define DRIVER_DESC "DRM driver for Hyper-V synthetic video device"
23 #define DRIVER_DATE "2020"
24 #define DRIVER_MAJOR 1
25 #define DRIVER_MINOR 0
26 
27 DEFINE_DRM_GEM_FOPS(hv_fops);
28 
29 static struct drm_driver hyperv_driver = {
30 	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
31 
32 	.name		 = DRIVER_NAME,
33 	.desc		 = DRIVER_DESC,
34 	.date		 = DRIVER_DATE,
35 	.major		 = DRIVER_MAJOR,
36 	.minor		 = DRIVER_MINOR,
37 
38 	.fops		 = &hv_fops,
39 	DRM_GEM_SHMEM_DRIVER_OPS,
40 };
41 
42 static int hyperv_pci_probe(struct pci_dev *pdev,
43 			    const struct pci_device_id *ent)
44 {
45 	return 0;
46 }
47 
48 static void hyperv_pci_remove(struct pci_dev *pdev)
49 {
50 }
51 
52 static const struct pci_device_id hyperv_pci_tbl[] = {
53 	{
54 		.vendor = PCI_VENDOR_ID_MICROSOFT,
55 		.device = PCI_DEVICE_ID_HYPERV_VIDEO,
56 	},
57 	{ /* end of list */ }
58 };
59 
60 /*
61  * PCI stub to support gen1 VM.
62  */
63 static struct pci_driver hyperv_pci_driver = {
64 	.name =		KBUILD_MODNAME,
65 	.id_table =	hyperv_pci_tbl,
66 	.probe =	hyperv_pci_probe,
67 	.remove =	hyperv_pci_remove,
68 };
69 
70 static int hyperv_setup_vram(struct hyperv_drm_device *hv,
71 			     struct hv_device *hdev)
72 {
73 	struct drm_device *dev = &hv->dev;
74 	int ret;
75 
76 	drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
77 						     screen_info.lfb_size,
78 						     &hyperv_driver);
79 
80 	hv->fb_size = (unsigned long)hv->mmio_megabytes * 1024 * 1024;
81 
82 	ret = vmbus_allocate_mmio(&hv->mem, hdev, 0, -1, hv->fb_size, 0x100000,
83 				  true);
84 	if (ret) {
85 		drm_err(dev, "Failed to allocate mmio\n");
86 		return -ENOMEM;
87 	}
88 
89 	/*
90 	 * Map the VRAM cacheable for performance. This is also required for VM
91 	 * connect to display properly for ARM64 Linux VM, as the host also maps
92 	 * the VRAM cacheable.
93 	 */
94 	hv->vram = ioremap_cache(hv->mem->start, hv->fb_size);
95 	if (!hv->vram) {
96 		drm_err(dev, "Failed to map vram\n");
97 		ret = -ENOMEM;
98 		goto error;
99 	}
100 
101 	hv->fb_base = hv->mem->start;
102 	return 0;
103 
104 error:
105 	vmbus_free_mmio(hv->mem->start, hv->fb_size);
106 	return ret;
107 }
108 
109 static int hyperv_vmbus_probe(struct hv_device *hdev,
110 			      const struct hv_vmbus_device_id *dev_id)
111 {
112 	struct hyperv_drm_device *hv;
113 	struct drm_device *dev;
114 	int ret;
115 
116 	hv = devm_drm_dev_alloc(&hdev->device, &hyperv_driver,
117 				struct hyperv_drm_device, dev);
118 	if (IS_ERR(hv))
119 		return PTR_ERR(hv);
120 
121 	dev = &hv->dev;
122 	init_completion(&hv->wait);
123 	hv_set_drvdata(hdev, hv);
124 	hv->hdev = hdev;
125 
126 	ret = hyperv_connect_vsp(hdev);
127 	if (ret) {
128 		drm_err(dev, "Failed to connect to vmbus.\n");
129 		goto err_hv_set_drv_data;
130 	}
131 
132 	ret = hyperv_setup_vram(hv, hdev);
133 	if (ret)
134 		goto err_vmbus_close;
135 
136 	/*
137 	 * Should be done only once during init and resume. Failing to update
138 	 * vram location is not fatal. Device will update dirty area till
139 	 * preferred resolution only.
140 	 */
141 	ret = hyperv_update_vram_location(hdev, hv->fb_base);
142 	if (ret)
143 		drm_warn(dev, "Failed to update vram location.\n");
144 
145 	ret = hyperv_mode_config_init(hv);
146 	if (ret)
147 		goto err_free_mmio;
148 
149 	ret = drm_dev_register(dev, 0);
150 	if (ret) {
151 		drm_err(dev, "Failed to register drm driver.\n");
152 		goto err_free_mmio;
153 	}
154 
155 	drm_fbdev_generic_setup(dev, 0);
156 
157 	return 0;
158 
159 err_free_mmio:
160 	vmbus_free_mmio(hv->mem->start, hv->fb_size);
161 err_vmbus_close:
162 	vmbus_close(hdev->channel);
163 err_hv_set_drv_data:
164 	hv_set_drvdata(hdev, NULL);
165 	return ret;
166 }
167 
168 static void hyperv_vmbus_remove(struct hv_device *hdev)
169 {
170 	struct drm_device *dev = hv_get_drvdata(hdev);
171 	struct hyperv_drm_device *hv = to_hv(dev);
172 
173 	drm_dev_unplug(dev);
174 	drm_atomic_helper_shutdown(dev);
175 	vmbus_close(hdev->channel);
176 	hv_set_drvdata(hdev, NULL);
177 
178 	vmbus_free_mmio(hv->mem->start, hv->fb_size);
179 }
180 
181 static int hyperv_vmbus_suspend(struct hv_device *hdev)
182 {
183 	struct drm_device *dev = hv_get_drvdata(hdev);
184 	int ret;
185 
186 	ret = drm_mode_config_helper_suspend(dev);
187 	if (ret)
188 		return ret;
189 
190 	vmbus_close(hdev->channel);
191 
192 	return 0;
193 }
194 
195 static int hyperv_vmbus_resume(struct hv_device *hdev)
196 {
197 	struct drm_device *dev = hv_get_drvdata(hdev);
198 	struct hyperv_drm_device *hv = to_hv(dev);
199 	int ret;
200 
201 	ret = hyperv_connect_vsp(hdev);
202 	if (ret)
203 		return ret;
204 
205 	ret = hyperv_update_vram_location(hdev, hv->fb_base);
206 	if (ret)
207 		return ret;
208 
209 	return drm_mode_config_helper_resume(dev);
210 }
211 
212 static const struct hv_vmbus_device_id hyperv_vmbus_tbl[] = {
213 	/* Synthetic Video Device GUID */
214 	{HV_SYNTHVID_GUID},
215 	{}
216 };
217 
218 static struct hv_driver hyperv_hv_driver = {
219 	.name = KBUILD_MODNAME,
220 	.id_table = hyperv_vmbus_tbl,
221 	.probe = hyperv_vmbus_probe,
222 	.remove = hyperv_vmbus_remove,
223 	.suspend = hyperv_vmbus_suspend,
224 	.resume = hyperv_vmbus_resume,
225 	.driver = {
226 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
227 	},
228 };
229 
230 static int __init hyperv_init(void)
231 {
232 	int ret;
233 
234 	if (drm_firmware_drivers_only())
235 		return -ENODEV;
236 
237 	ret = pci_register_driver(&hyperv_pci_driver);
238 	if (ret != 0)
239 		return ret;
240 
241 	return vmbus_driver_register(&hyperv_hv_driver);
242 }
243 
244 static void __exit hyperv_exit(void)
245 {
246 	vmbus_driver_unregister(&hyperv_hv_driver);
247 	pci_unregister_driver(&hyperv_pci_driver);
248 }
249 
250 module_init(hyperv_init);
251 module_exit(hyperv_exit);
252 
253 MODULE_DEVICE_TABLE(pci, hyperv_pci_tbl);
254 MODULE_DEVICE_TABLE(vmbus, hyperv_vmbus_tbl);
255 MODULE_LICENSE("GPL");
256 MODULE_AUTHOR("Deepak Rawat <drawat.floss@gmail.com>");
257 MODULE_DESCRIPTION("DRM driver for Hyper-V synthetic video device");
258