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 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 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 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 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 } 105 106 static void hub_master_release(struct device *dev) 107 { 108 struct fsi_master_hub *hub = to_fsi_master_hub(dev_to_fsi_master(dev)); 109 110 kfree(hub); 111 } 112 113 /* mmode encoders */ 114 static inline u32 fsi_mmode_crs0(u32 x) 115 { 116 return (x & FSI_MMODE_CRS0MASK) << FSI_MMODE_CRS0SHFT; 117 } 118 119 static inline u32 fsi_mmode_crs1(u32 x) 120 { 121 return (x & FSI_MMODE_CRS1MASK) << FSI_MMODE_CRS1SHFT; 122 } 123 124 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 } 194 195 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 } 261 262 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