LXR linux/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 */
  36struct 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
  45static 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
  57static 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
  69static 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
  80static 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                                        &reg, 4);
  96
  97        rc = fsi_device_write(hub->upstream, FSI_MSENP0 + (4 * idx), &reg, 4);
  98        if (rc)
  99                return rc;
 100
 101        mdelay(FSI_LINK_ENABLE_SETUP_TIME);
 102
 103        return 0;
 104}
 105
 106static 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 */
 114static inline u32 fsi_mmode_crs0(u32 x)
 115{
 116        return (x & FSI_MMODE_CRS0MASK) << FSI_MMODE_CRS0SHFT;
 117}
 118
 119static inline u32 fsi_mmode_crs1(u32 x)
 120{
 121        return (x & FSI_MMODE_CRS1MASK) << FSI_MMODE_CRS1SHFT;
 122}
 123
 124static 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, &reg, 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, &reg, 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, &reg, 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, &reg, sizeof(reg));
 152        if (rc)
 153                return rc;
 154
 155        reg = cpu_to_be32(0xffff0000);
 156        rc = fsi_device_write(dev, FSI_MDLYR, &reg, sizeof(reg));
 157        if (rc)
 158                return rc;
 159
 160        reg = cpu_to_be32(~0);
 161        rc = fsi_device_write(dev, FSI_MSENP0, &reg, 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, &reg, sizeof(reg));
 169        if (rc)
 170                return rc;
 171
 172        rc = fsi_device_read(dev, FSI_MAEB, &reg, 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, &reg, sizeof(reg));
 178        if (rc)
 179                return rc;
 180
 181        rc = fsi_device_read(dev, FSI_MLEVP0, &reg, 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, &reg, 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, &reg, sizeof(reg));
 193}
 194
 195static 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
 256err_release:
 257        fsi_slave_release_range(fsi_dev->slave, FSI_HUB_LINK_OFFSET,
 258                        FSI_HUB_LINK_SIZE * links);
 259        return rc;
 260}
 261
 262static 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
 279static 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
 287static 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
 297module_fsi_driver(hub_master_driver);
 298MODULE_LICENSE("GPL");
 299