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 { 82 struct fsi_master_hub *hub = to_fsi_master_hub(master); 83 int idx, bit; 84 __be32 reg; 85 int rc; 86 87 idx = link / 32; 88 bit = link % 32; 89 90 reg = cpu_to_be32(0x80000000 >> bit); 91 92 rc = fsi_device_write(hub->upstream, FSI_MSENP0 + (4 * idx), ®, 4); 93 94 mdelay(FSI_LINK_ENABLE_SETUP_TIME); 95 96 fsi_device_read(hub->upstream, FSI_MENP0 + (4 * idx), ®, 4); 97 98 return rc; 99 } 100 101 static void hub_master_release(struct device *dev) 102 { 103 struct fsi_master_hub *hub = to_fsi_master_hub(dev_to_fsi_master(dev)); 104 105 kfree(hub); 106 } 107 108 /* mmode encoders */ 109 static inline u32 fsi_mmode_crs0(u32 x) 110 { 111 return (x & FSI_MMODE_CRS0MASK) << FSI_MMODE_CRS0SHFT; 112 } 113 114 static inline u32 fsi_mmode_crs1(u32 x) 115 { 116 return (x & FSI_MMODE_CRS1MASK) << FSI_MMODE_CRS1SHFT; 117 } 118 119 static int hub_master_init(struct fsi_master_hub *hub) 120 { 121 struct fsi_device *dev = hub->upstream; 122 __be32 reg; 123 int rc; 124 125 reg = cpu_to_be32(FSI_MRESP_RST_ALL_MASTER | FSI_MRESP_RST_ALL_LINK 126 | FSI_MRESP_RST_MCR | FSI_MRESP_RST_PYE); 127 rc = fsi_device_write(dev, FSI_MRESP0, ®, sizeof(reg)); 128 if (rc) 129 return rc; 130 131 /* Initialize the MFSI (hub master) engine */ 132 reg = cpu_to_be32(FSI_MRESP_RST_ALL_MASTER | FSI_MRESP_RST_ALL_LINK 133 | FSI_MRESP_RST_MCR | FSI_MRESP_RST_PYE); 134 rc = fsi_device_write(dev, FSI_MRESP0, ®, sizeof(reg)); 135 if (rc) 136 return rc; 137 138 reg = cpu_to_be32(FSI_MECTRL_EOAE | FSI_MECTRL_P8_AUTO_TERM); 139 rc = fsi_device_write(dev, FSI_MECTRL, ®, sizeof(reg)); 140 if (rc) 141 return rc; 142 143 reg = cpu_to_be32(FSI_MMODE_EIP | FSI_MMODE_ECRC | FSI_MMODE_EPC 144 | fsi_mmode_crs0(1) | fsi_mmode_crs1(1) 145 | FSI_MMODE_P8_TO_LSB); 146 rc = fsi_device_write(dev, FSI_MMODE, ®, sizeof(reg)); 147 if (rc) 148 return rc; 149 150 reg = cpu_to_be32(0xffff0000); 151 rc = fsi_device_write(dev, FSI_MDLYR, ®, sizeof(reg)); 152 if (rc) 153 return rc; 154 155 reg = cpu_to_be32(~0); 156 rc = fsi_device_write(dev, FSI_MSENP0, ®, sizeof(reg)); 157 if (rc) 158 return rc; 159 160 /* Leave enabled long enough for master logic to set up */ 161 mdelay(FSI_LINK_ENABLE_SETUP_TIME); 162 163 rc = fsi_device_write(dev, FSI_MCENP0, ®, sizeof(reg)); 164 if (rc) 165 return rc; 166 167 rc = fsi_device_read(dev, FSI_MAEB, ®, sizeof(reg)); 168 if (rc) 169 return rc; 170 171 reg = cpu_to_be32(FSI_MRESP_RST_ALL_MASTER | FSI_MRESP_RST_ALL_LINK); 172 rc = fsi_device_write(dev, FSI_MRESP0, ®, sizeof(reg)); 173 if (rc) 174 return rc; 175 176 rc = fsi_device_read(dev, FSI_MLEVP0, ®, sizeof(reg)); 177 if (rc) 178 return rc; 179 180 /* Reset the master bridge */ 181 reg = cpu_to_be32(FSI_MRESB_RST_GEN); 182 rc = fsi_device_write(dev, FSI_MRESB0, ®, sizeof(reg)); 183 if (rc) 184 return rc; 185 186 reg = cpu_to_be32(FSI_MRESB_RST_ERR); 187 return fsi_device_write(dev, FSI_MRESB0, ®, sizeof(reg)); 188 } 189 190 static int hub_master_probe(struct device *dev) 191 { 192 struct fsi_device *fsi_dev = to_fsi_dev(dev); 193 struct fsi_master_hub *hub; 194 uint32_t reg, links; 195 __be32 __reg; 196 int rc; 197 198 rc = fsi_device_read(fsi_dev, FSI_MVER, &__reg, sizeof(__reg)); 199 if (rc) 200 return rc; 201 202 reg = be32_to_cpu(__reg); 203 links = (reg >> 8) & 0xff; 204 dev_dbg(dev, "hub version %08x (%d links)\n", reg, links); 205 206 rc = fsi_slave_claim_range(fsi_dev->slave, FSI_HUB_LINK_OFFSET, 207 FSI_HUB_LINK_SIZE * links); 208 if (rc) { 209 dev_err(dev, "can't claim slave address range for links"); 210 return rc; 211 } 212 213 hub = kzalloc(sizeof(*hub), GFP_KERNEL); 214 if (!hub) { 215 rc = -ENOMEM; 216 goto err_release; 217 } 218 219 hub->addr = FSI_HUB_LINK_OFFSET; 220 hub->size = FSI_HUB_LINK_SIZE * links; 221 hub->upstream = fsi_dev; 222 223 hub->master.dev.parent = dev; 224 hub->master.dev.release = hub_master_release; 225 hub->master.dev.of_node = of_node_get(dev_of_node(dev)); 226 227 hub->master.n_links = links; 228 hub->master.read = hub_master_read; 229 hub->master.write = hub_master_write; 230 hub->master.send_break = hub_master_break; 231 hub->master.link_enable = hub_master_link_enable; 232 233 dev_set_drvdata(dev, hub); 234 235 hub_master_init(hub); 236 237 rc = fsi_master_register(&hub->master); 238 if (rc) 239 goto err_release; 240 241 /* At this point, fsi_master_register performs the device_initialize(), 242 * and holds the sole reference on master.dev. This means the device 243 * will be freed (via ->release) during any subsequent call to 244 * fsi_master_unregister. We add our own reference to it here, so we 245 * can perform cleanup (in _remove()) without it being freed before 246 * we're ready. 247 */ 248 get_device(&hub->master.dev); 249 return 0; 250 251 err_release: 252 fsi_slave_release_range(fsi_dev->slave, FSI_HUB_LINK_OFFSET, 253 FSI_HUB_LINK_SIZE * links); 254 return rc; 255 } 256 257 static int hub_master_remove(struct device *dev) 258 { 259 struct fsi_master_hub *hub = dev_get_drvdata(dev); 260 261 fsi_master_unregister(&hub->master); 262 fsi_slave_release_range(hub->upstream->slave, hub->addr, hub->size); 263 of_node_put(hub->master.dev.of_node); 264 265 /* 266 * master.dev will likely be ->release()ed after this, which free()s 267 * the hub 268 */ 269 put_device(&hub->master.dev); 270 271 return 0; 272 } 273 274 static struct fsi_device_id hub_master_ids[] = { 275 { 276 .engine_type = FSI_ENGID_HUB_MASTER, 277 .version = FSI_VERSION_ANY, 278 }, 279 { 0 } 280 }; 281 282 static struct fsi_driver hub_master_driver = { 283 .id_table = hub_master_ids, 284 .drv = { 285 .name = "fsi-master-hub", 286 .bus = &fsi_bus_type, 287 .probe = hub_master_probe, 288 .remove = hub_master_remove, 289 } 290 }; 291 292 module_fsi_driver(hub_master_driver); 293 MODULE_LICENSE("GPL"); 294