1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * FSI hub master driver
4 *
5 * Copyright (C) IBM Corporation 2016
6 */
7
8 #include <linux/delay.h>
9 #include <linux/fsi.h>
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/slab.h>
13
14 #include "fsi-master.h"
15
16 #define FSI_ENGID_HUB_MASTER 0x1c
17
18 #define FSI_LINK_ENABLE_SETUP_TIME 10 /* in mS */
19
20 /*
21 * FSI hub master support
22 *
23 * A hub master increases the number of potential target devices that the
24 * primary FSI master can access. For each link a primary master supports,
25 * each of those links can in turn be chained to a hub master with multiple
26 * links of its own.
27 *
28 * The hub is controlled by a set of control registers exposed as a regular fsi
29 * device (the hub->upstream device), and provides access to the downstream FSI
30 * bus as through an address range on the slave itself (->addr and ->size).
31 *
32 * [This differs from "cascaded" masters, which expose the entire downstream
33 * bus entirely through the fsi device address range, and so have a smaller
34 * accessible address space.]
35 */
36 struct fsi_master_hub {
37 struct fsi_master master;
38 struct fsi_device *upstream;
39 uint32_t addr, size; /* slave-relative addr of */
40 /* master address space */
41 };
42
43 #define to_fsi_master_hub(m) container_of(m, struct fsi_master_hub, master)
44
hub_master_read(struct fsi_master * master,int link,uint8_t id,uint32_t addr,void * val,size_t size)45 static int hub_master_read(struct fsi_master *master, int link,
46 uint8_t id, uint32_t addr, void *val, size_t size)
47 {
48 struct fsi_master_hub *hub = to_fsi_master_hub(master);
49
50 if (id != 0)
51 return -EINVAL;
52
53 addr += hub->addr + (link * FSI_HUB_LINK_SIZE);
54 return fsi_slave_read(hub->upstream->slave, addr, val, size);
55 }
56
hub_master_write(struct fsi_master * master,int link,uint8_t id,uint32_t addr,const void * val,size_t size)57 static int hub_master_write(struct fsi_master *master, int link,
58 uint8_t id, uint32_t addr, const void *val, size_t size)
59 {
60 struct fsi_master_hub *hub = to_fsi_master_hub(master);
61
62 if (id != 0)
63 return -EINVAL;
64
65 addr += hub->addr + (link * FSI_HUB_LINK_SIZE);
66 return fsi_slave_write(hub->upstream->slave, addr, val, size);
67 }
68
hub_master_break(struct fsi_master * master,int link)69 static int hub_master_break(struct fsi_master *master, int link)
70 {
71 uint32_t addr;
72 __be32 cmd;
73
74 addr = 0x4;
75 cmd = cpu_to_be32(0xc0de0000);
76
77 return hub_master_write(master, link, 0, addr, &cmd, sizeof(cmd));
78 }
79
hub_master_link_enable(struct fsi_master * master,int link,bool enable)80 static int hub_master_link_enable(struct fsi_master *master, int link,
81 bool enable)
82 {
83 struct fsi_master_hub *hub = to_fsi_master_hub(master);
84 int idx, bit;
85 __be32 reg;
86 int rc;
87
88 idx = link / 32;
89 bit = link % 32;
90
91 reg = cpu_to_be32(0x80000000 >> bit);
92
93 if (!enable)
94 return fsi_device_write(hub->upstream, FSI_MCENP0 + (4 * idx),
95 ®, 4);
96
97 rc = fsi_device_write(hub->upstream, FSI_MSENP0 + (4 * idx), ®, 4);
98 if (rc)
99 return rc;
100
101 mdelay(FSI_LINK_ENABLE_SETUP_TIME);
102
103 return 0;
104 }
105
hub_master_release(struct device * dev)106 static void hub_master_release(struct device *dev)
107 {
108 struct fsi_master_hub *hub = to_fsi_master_hub(to_fsi_master(dev));
109
110 kfree(hub);
111 }
112
113 /* mmode encoders */
fsi_mmode_crs0(u32 x)114 static inline u32 fsi_mmode_crs0(u32 x)
115 {
116 return (x & FSI_MMODE_CRS0MASK) << FSI_MMODE_CRS0SHFT;
117 }
118
fsi_mmode_crs1(u32 x)119 static inline u32 fsi_mmode_crs1(u32 x)
120 {
121 return (x & FSI_MMODE_CRS1MASK) << FSI_MMODE_CRS1SHFT;
122 }
123
hub_master_init(struct fsi_master_hub * hub)124 static int hub_master_init(struct fsi_master_hub *hub)
125 {
126 struct fsi_device *dev = hub->upstream;
127 __be32 reg;
128 int rc;
129
130 reg = cpu_to_be32(FSI_MRESP_RST_ALL_MASTER | FSI_MRESP_RST_ALL_LINK
131 | FSI_MRESP_RST_MCR | FSI_MRESP_RST_PYE);
132 rc = fsi_device_write(dev, FSI_MRESP0, ®, sizeof(reg));
133 if (rc)
134 return rc;
135
136 /* Initialize the MFSI (hub master) engine */
137 reg = cpu_to_be32(FSI_MRESP_RST_ALL_MASTER | FSI_MRESP_RST_ALL_LINK
138 | FSI_MRESP_RST_MCR | FSI_MRESP_RST_PYE);
139 rc = fsi_device_write(dev, FSI_MRESP0, ®, sizeof(reg));
140 if (rc)
141 return rc;
142
143 reg = cpu_to_be32(FSI_MECTRL_EOAE | FSI_MECTRL_P8_AUTO_TERM);
144 rc = fsi_device_write(dev, FSI_MECTRL, ®, sizeof(reg));
145 if (rc)
146 return rc;
147
148 reg = cpu_to_be32(FSI_MMODE_EIP | FSI_MMODE_ECRC | FSI_MMODE_EPC
149 | fsi_mmode_crs0(1) | fsi_mmode_crs1(1)
150 | FSI_MMODE_P8_TO_LSB);
151 rc = fsi_device_write(dev, FSI_MMODE, ®, sizeof(reg));
152 if (rc)
153 return rc;
154
155 reg = cpu_to_be32(0xffff0000);
156 rc = fsi_device_write(dev, FSI_MDLYR, ®, sizeof(reg));
157 if (rc)
158 return rc;
159
160 reg = cpu_to_be32(~0);
161 rc = fsi_device_write(dev, FSI_MSENP0, ®, sizeof(reg));
162 if (rc)
163 return rc;
164
165 /* Leave enabled long enough for master logic to set up */
166 mdelay(FSI_LINK_ENABLE_SETUP_TIME);
167
168 rc = fsi_device_write(dev, FSI_MCENP0, ®, sizeof(reg));
169 if (rc)
170 return rc;
171
172 rc = fsi_device_read(dev, FSI_MAEB, ®, sizeof(reg));
173 if (rc)
174 return rc;
175
176 reg = cpu_to_be32(FSI_MRESP_RST_ALL_MASTER | FSI_MRESP_RST_ALL_LINK);
177 rc = fsi_device_write(dev, FSI_MRESP0, ®, sizeof(reg));
178 if (rc)
179 return rc;
180
181 rc = fsi_device_read(dev, FSI_MLEVP0, ®, sizeof(reg));
182 if (rc)
183 return rc;
184
185 /* Reset the master bridge */
186 reg = cpu_to_be32(FSI_MRESB_RST_GEN);
187 rc = fsi_device_write(dev, FSI_MRESB0, ®, sizeof(reg));
188 if (rc)
189 return rc;
190
191 reg = cpu_to_be32(FSI_MRESB_RST_ERR);
192 return fsi_device_write(dev, FSI_MRESB0, ®, sizeof(reg));
193 }
194
hub_master_probe(struct device * dev)195 static int hub_master_probe(struct device *dev)
196 {
197 struct fsi_device *fsi_dev = to_fsi_dev(dev);
198 struct fsi_master_hub *hub;
199 uint32_t reg, links;
200 __be32 __reg;
201 int rc;
202
203 rc = fsi_device_read(fsi_dev, FSI_MVER, &__reg, sizeof(__reg));
204 if (rc)
205 return rc;
206
207 reg = be32_to_cpu(__reg);
208 links = (reg >> 8) & 0xff;
209 dev_dbg(dev, "hub version %08x (%d links)\n", reg, links);
210
211 rc = fsi_slave_claim_range(fsi_dev->slave, FSI_HUB_LINK_OFFSET,
212 FSI_HUB_LINK_SIZE * links);
213 if (rc) {
214 dev_err(dev, "can't claim slave address range for links");
215 return rc;
216 }
217
218 hub = kzalloc(sizeof(*hub), GFP_KERNEL);
219 if (!hub) {
220 rc = -ENOMEM;
221 goto err_release;
222 }
223
224 hub->addr = FSI_HUB_LINK_OFFSET;
225 hub->size = FSI_HUB_LINK_SIZE * links;
226 hub->upstream = fsi_dev;
227
228 hub->master.dev.parent = dev;
229 hub->master.dev.release = hub_master_release;
230 hub->master.dev.of_node = of_node_get(dev_of_node(dev));
231
232 hub->master.n_links = links;
233 hub->master.read = hub_master_read;
234 hub->master.write = hub_master_write;
235 hub->master.send_break = hub_master_break;
236 hub->master.link_enable = hub_master_link_enable;
237
238 dev_set_drvdata(dev, hub);
239
240 hub_master_init(hub);
241
242 rc = fsi_master_register(&hub->master);
243 if (rc)
244 goto err_release;
245
246 /* At this point, fsi_master_register performs the device_initialize(),
247 * and holds the sole reference on master.dev. This means the device
248 * will be freed (via ->release) during any subsequent call to
249 * fsi_master_unregister. We add our own reference to it here, so we
250 * can perform cleanup (in _remove()) without it being freed before
251 * we're ready.
252 */
253 get_device(&hub->master.dev);
254 return 0;
255
256 err_release:
257 fsi_slave_release_range(fsi_dev->slave, FSI_HUB_LINK_OFFSET,
258 FSI_HUB_LINK_SIZE * links);
259 return rc;
260 }
261
hub_master_remove(struct device * dev)262 static int hub_master_remove(struct device *dev)
263 {
264 struct fsi_master_hub *hub = dev_get_drvdata(dev);
265
266 fsi_master_unregister(&hub->master);
267 fsi_slave_release_range(hub->upstream->slave, hub->addr, hub->size);
268 of_node_put(hub->master.dev.of_node);
269
270 /*
271 * master.dev will likely be ->release()ed after this, which free()s
272 * the hub
273 */
274 put_device(&hub->master.dev);
275
276 return 0;
277 }
278
279 static const struct fsi_device_id hub_master_ids[] = {
280 {
281 .engine_type = FSI_ENGID_HUB_MASTER,
282 .version = FSI_VERSION_ANY,
283 },
284 { 0 }
285 };
286
287 static struct fsi_driver hub_master_driver = {
288 .id_table = hub_master_ids,
289 .drv = {
290 .name = "fsi-master-hub",
291 .bus = &fsi_bus_type,
292 .probe = hub_master_probe,
293 .remove = hub_master_remove,
294 }
295 };
296
297 module_fsi_driver(hub_master_driver);
298 MODULE_LICENSE("GPL");
299