drivers/fsi/fsi-master-hub.c

   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), &reg, 4);
  93
  94         mdelay(FSI_LINK_ENABLE_SETUP_TIME);
  95
  96         fsi_device_read(hub->upstream, FSI_MENP0 + (4 * idx), &reg, 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, &reg, 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, &reg, 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, &reg, 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, &reg, sizeof(reg));
 147         if (rc)
 148                 return rc;
 149
 150         reg = cpu_to_be32(0xffff0000);
 151         rc = fsi_device_write(dev, FSI_MDLYR, &reg, sizeof(reg));
 152         if (rc)
 153                 return rc;
 154
 155         reg = cpu_to_be32(~0);
 156         rc = fsi_device_write(dev, FSI_MSENP0, &reg, 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, &reg, sizeof(reg));
 164         if (rc)
 165                 return rc;
 166
 167         rc = fsi_device_read(dev, FSI_MAEB, &reg, 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, &reg, sizeof(reg));
 173         if (rc)
 174                 return rc;
 175
 176         rc = fsi_device_read(dev, FSI_MLEVP0, &reg, 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, &reg, 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, &reg, 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");