linux/drivers/misc/cxl/main.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Copyright 2014 IBM Corp.
   4 */
   5
   6#include <linux/spinlock.h>
   7#include <linux/kernel.h>
   8#include <linux/module.h>
   9#include <linux/device.h>
  10#include <linux/mutex.h>
  11#include <linux/init.h>
  12#include <linux/list.h>
  13#include <linux/mm.h>
  14#include <linux/of.h>
  15#include <linux/slab.h>
  16#include <linux/idr.h>
  17#include <linux/pci.h>
  18#include <linux/sched/task.h>
  19
  20#include <asm/cputable.h>
  21#include <asm/mmu.h>
  22#include <misc/cxl-base.h>
  23
  24#include "cxl.h"
  25#include "trace.h"
  26
  27static DEFINE_SPINLOCK(adapter_idr_lock);
  28static DEFINE_IDR(cxl_adapter_idr);
  29
  30uint cxl_verbose;
  31module_param_named(verbose, cxl_verbose, uint, 0600);
  32MODULE_PARM_DESC(verbose, "Enable verbose dmesg output");
  33
  34const struct cxl_backend_ops *cxl_ops;
  35
  36int cxl_afu_slbia(struct cxl_afu *afu)
  37{
  38        unsigned long timeout = jiffies + (HZ * CXL_TIMEOUT);
  39
  40        pr_devel("cxl_afu_slbia issuing SLBIA command\n");
  41        cxl_p2n_write(afu, CXL_SLBIA_An, CXL_TLB_SLB_IQ_ALL);
  42        while (cxl_p2n_read(afu, CXL_SLBIA_An) & CXL_TLB_SLB_P) {
  43                if (time_after_eq(jiffies, timeout)) {
  44                        dev_warn(&afu->dev, "WARNING: CXL AFU SLBIA timed out!\n");
  45                        return -EBUSY;
  46                }
  47                /* If the adapter has gone down, we can assume that we
  48                 * will PERST it and that will invalidate everything.
  49                 */
  50                if (!cxl_ops->link_ok(afu->adapter, afu))
  51                        return -EIO;
  52                cpu_relax();
  53        }
  54        return 0;
  55}
  56
  57static inline void _cxl_slbia(struct cxl_context *ctx, struct mm_struct *mm)
  58{
  59        unsigned long flags;
  60
  61        if (ctx->mm != mm)
  62                return;
  63
  64        pr_devel("%s matched mm - card: %i afu: %i pe: %i\n", __func__,
  65                 ctx->afu->adapter->adapter_num, ctx->afu->slice, ctx->pe);
  66
  67        spin_lock_irqsave(&ctx->sste_lock, flags);
  68        trace_cxl_slbia(ctx);
  69        memset(ctx->sstp, 0, ctx->sst_size);
  70        spin_unlock_irqrestore(&ctx->sste_lock, flags);
  71        mb();
  72        cxl_afu_slbia(ctx->afu);
  73}
  74
  75static inline void cxl_slbia_core(struct mm_struct *mm)
  76{
  77        struct cxl *adapter;
  78        struct cxl_afu *afu;
  79        struct cxl_context *ctx;
  80        int card, slice, id;
  81
  82        pr_devel("%s called\n", __func__);
  83
  84        spin_lock(&adapter_idr_lock);
  85        idr_for_each_entry(&cxl_adapter_idr, adapter, card) {
  86                /* XXX: Make this lookup faster with link from mm to ctx */
  87                spin_lock(&adapter->afu_list_lock);
  88                for (slice = 0; slice < adapter->slices; slice++) {
  89                        afu = adapter->afu[slice];
  90                        if (!afu || !afu->enabled)
  91                                continue;
  92                        rcu_read_lock();
  93                        idr_for_each_entry(&afu->contexts_idr, ctx, id)
  94                                _cxl_slbia(ctx, mm);
  95                        rcu_read_unlock();
  96                }
  97                spin_unlock(&adapter->afu_list_lock);
  98        }
  99        spin_unlock(&adapter_idr_lock);
 100}
 101
 102static struct cxl_calls cxl_calls = {
 103        .cxl_slbia = cxl_slbia_core,
 104        .owner = THIS_MODULE,
 105};
 106
 107int cxl_alloc_sst(struct cxl_context *ctx)
 108{
 109        unsigned long vsid;
 110        u64 ea_mask, size, sstp0, sstp1;
 111
 112        sstp0 = 0;
 113        sstp1 = 0;
 114
 115        ctx->sst_size = PAGE_SIZE;
 116        ctx->sst_lru = 0;
 117        ctx->sstp = (struct cxl_sste *)get_zeroed_page(GFP_KERNEL);
 118        if (!ctx->sstp) {
 119                pr_err("cxl_alloc_sst: Unable to allocate segment table\n");
 120                return -ENOMEM;
 121        }
 122        pr_devel("SSTP allocated at 0x%p\n", ctx->sstp);
 123
 124        vsid  = get_kernel_vsid((u64)ctx->sstp, mmu_kernel_ssize) << 12;
 125
 126        sstp0 |= (u64)mmu_kernel_ssize << CXL_SSTP0_An_B_SHIFT;
 127        sstp0 |= (SLB_VSID_KERNEL | mmu_psize_defs[mmu_linear_psize].sllp) << 50;
 128
 129        size = (((u64)ctx->sst_size >> 8) - 1) << CXL_SSTP0_An_SegTableSize_SHIFT;
 130        if (unlikely(size & ~CXL_SSTP0_An_SegTableSize_MASK)) {
 131                WARN(1, "Impossible segment table size\n");
 132                return -EINVAL;
 133        }
 134        sstp0 |= size;
 135
 136        if (mmu_kernel_ssize == MMU_SEGSIZE_256M)
 137                ea_mask = 0xfffff00ULL;
 138        else
 139                ea_mask = 0xffffffff00ULL;
 140
 141        sstp0 |=  vsid >>     (50-14);  /*   Top 14 bits of VSID */
 142        sstp1 |= (vsid << (64-(50-14))) & ~ea_mask;
 143        sstp1 |= (u64)ctx->sstp & ea_mask;
 144        sstp1 |= CXL_SSTP1_An_V;
 145
 146        pr_devel("Looked up %#llx: slbfee. %#llx (ssize: %x, vsid: %#lx), copied to SSTP0: %#llx, SSTP1: %#llx\n",
 147                        (u64)ctx->sstp, (u64)ctx->sstp & ESID_MASK, mmu_kernel_ssize, vsid, sstp0, sstp1);
 148
 149        /* Store calculated sstp hardware points for use later */
 150        ctx->sstp0 = sstp0;
 151        ctx->sstp1 = sstp1;
 152
 153        return 0;
 154}
 155
 156/* print buffer content as integers when debugging */
 157void cxl_dump_debug_buffer(void *buf, size_t buf_len)
 158{
 159#ifdef DEBUG
 160        int i, *ptr;
 161
 162        /*
 163         * We want to regroup up to 4 integers per line, which means they
 164         * need to be in the same pr_devel() statement
 165         */
 166        ptr = (int *) buf;
 167        for (i = 0; i * 4 < buf_len; i += 4) {
 168                if ((i + 3) * 4 < buf_len)
 169                        pr_devel("%.8x %.8x %.8x %.8x\n", ptr[i], ptr[i + 1],
 170                                ptr[i + 2], ptr[i + 3]);
 171                else if ((i + 2) * 4 < buf_len)
 172                        pr_devel("%.8x %.8x %.8x\n", ptr[i], ptr[i + 1],
 173                                ptr[i + 2]);
 174                else if ((i + 1) * 4 < buf_len)
 175                        pr_devel("%.8x %.8x\n", ptr[i], ptr[i + 1]);
 176                else
 177                        pr_devel("%.8x\n", ptr[i]);
 178        }
 179#endif /* DEBUG */
 180}
 181
 182/* Find a CXL adapter by it's number and increase it's refcount */
 183struct cxl *get_cxl_adapter(int num)
 184{
 185        struct cxl *adapter;
 186
 187        spin_lock(&adapter_idr_lock);
 188        if ((adapter = idr_find(&cxl_adapter_idr, num)))
 189                get_device(&adapter->dev);
 190        spin_unlock(&adapter_idr_lock);
 191
 192        return adapter;
 193}
 194
 195static int cxl_alloc_adapter_nr(struct cxl *adapter)
 196{
 197        int i;
 198
 199        idr_preload(GFP_KERNEL);
 200        spin_lock(&adapter_idr_lock);
 201        i = idr_alloc(&cxl_adapter_idr, adapter, 0, 0, GFP_NOWAIT);
 202        spin_unlock(&adapter_idr_lock);
 203        idr_preload_end();
 204        if (i < 0)
 205                return i;
 206
 207        adapter->adapter_num = i;
 208
 209        return 0;
 210}
 211
 212void cxl_remove_adapter_nr(struct cxl *adapter)
 213{
 214        idr_remove(&cxl_adapter_idr, adapter->adapter_num);
 215}
 216
 217struct cxl *cxl_alloc_adapter(void)
 218{
 219        struct cxl *adapter;
 220
 221        if (!(adapter = kzalloc(sizeof(struct cxl), GFP_KERNEL)))
 222                return NULL;
 223
 224        spin_lock_init(&adapter->afu_list_lock);
 225
 226        if (cxl_alloc_adapter_nr(adapter))
 227                goto err1;
 228
 229        if (dev_set_name(&adapter->dev, "card%i", adapter->adapter_num))
 230                goto err2;
 231
 232        /* start with context lock taken */
 233        atomic_set(&adapter->contexts_num, -1);
 234
 235        return adapter;
 236err2:
 237        cxl_remove_adapter_nr(adapter);
 238err1:
 239        kfree(adapter);
 240        return NULL;
 241}
 242
 243struct cxl_afu *cxl_alloc_afu(struct cxl *adapter, int slice)
 244{
 245        struct cxl_afu *afu;
 246
 247        if (!(afu = kzalloc(sizeof(struct cxl_afu), GFP_KERNEL)))
 248                return NULL;
 249
 250        afu->adapter = adapter;
 251        afu->dev.parent = &adapter->dev;
 252        afu->dev.release = cxl_ops->release_afu;
 253        afu->slice = slice;
 254        idr_init(&afu->contexts_idr);
 255        mutex_init(&afu->contexts_lock);
 256        spin_lock_init(&afu->afu_cntl_lock);
 257        atomic_set(&afu->configured_state, -1);
 258        afu->prefault_mode = CXL_PREFAULT_NONE;
 259        afu->irqs_max = afu->adapter->user_irqs;
 260
 261        return afu;
 262}
 263
 264int cxl_afu_select_best_mode(struct cxl_afu *afu)
 265{
 266        if (afu->modes_supported & CXL_MODE_DIRECTED)
 267                return cxl_ops->afu_activate_mode(afu, CXL_MODE_DIRECTED);
 268
 269        if (afu->modes_supported & CXL_MODE_DEDICATED)
 270                return cxl_ops->afu_activate_mode(afu, CXL_MODE_DEDICATED);
 271
 272        dev_warn(&afu->dev, "No supported programming modes available\n");
 273        /* We don't fail this so the user can inspect sysfs */
 274        return 0;
 275}
 276
 277int cxl_adapter_context_get(struct cxl *adapter)
 278{
 279        int rc;
 280
 281        rc = atomic_inc_unless_negative(&adapter->contexts_num);
 282        return rc ? 0 : -EBUSY;
 283}
 284
 285void cxl_adapter_context_put(struct cxl *adapter)
 286{
 287        atomic_dec_if_positive(&adapter->contexts_num);
 288}
 289
 290int cxl_adapter_context_lock(struct cxl *adapter)
 291{
 292        int rc;
 293        /* no active contexts -> contexts_num == 0 */
 294        rc = atomic_cmpxchg(&adapter->contexts_num, 0, -1);
 295        return rc ? -EBUSY : 0;
 296}
 297
 298void cxl_adapter_context_unlock(struct cxl *adapter)
 299{
 300        int val = atomic_cmpxchg(&adapter->contexts_num, -1, 0);
 301
 302        /*
 303         * contexts lock taken -> contexts_num == -1
 304         * If not true then show a warning and force reset the lock.
 305         * This will happen when context_unlock was requested without
 306         * doing a context_lock.
 307         */
 308        if (val != -1) {
 309                atomic_set(&adapter->contexts_num, 0);
 310                WARN(1, "Adapter context unlocked with %d active contexts",
 311                     val);
 312        }
 313}
 314
 315static int __init init_cxl(void)
 316{
 317        int rc = 0;
 318
 319        if (!tlbie_capable)
 320                return -EINVAL;
 321
 322        if ((rc = cxl_file_init()))
 323                return rc;
 324
 325        cxl_debugfs_init();
 326
 327        /*
 328         * we don't register the callback on P9. slb callack is only
 329         * used for the PSL8 MMU and CX4.
 330         */
 331        if (cxl_is_power8()) {
 332                rc = register_cxl_calls(&cxl_calls);
 333                if (rc)
 334                        goto err;
 335        }
 336
 337        if (cpu_has_feature(CPU_FTR_HVMODE)) {
 338                cxl_ops = &cxl_native_ops;
 339                rc = pci_register_driver(&cxl_pci_driver);
 340        }
 341#ifdef CONFIG_PPC_PSERIES
 342        else {
 343                cxl_ops = &cxl_guest_ops;
 344                rc = platform_driver_register(&cxl_of_driver);
 345        }
 346#endif
 347        if (rc)
 348                goto err1;
 349
 350        return 0;
 351err1:
 352        if (cxl_is_power8())
 353                unregister_cxl_calls(&cxl_calls);
 354err:
 355        cxl_debugfs_exit();
 356        cxl_file_exit();
 357
 358        return rc;
 359}
 360
 361static void exit_cxl(void)
 362{
 363        if (cpu_has_feature(CPU_FTR_HVMODE))
 364                pci_unregister_driver(&cxl_pci_driver);
 365#ifdef CONFIG_PPC_PSERIES
 366        else
 367                platform_driver_unregister(&cxl_of_driver);
 368#endif
 369
 370        cxl_debugfs_exit();
 371        cxl_file_exit();
 372        if (cxl_is_power8())
 373                unregister_cxl_calls(&cxl_calls);
 374        idr_destroy(&cxl_adapter_idr);
 375}
 376
 377module_init(init_cxl);
 378module_exit(exit_cxl);
 379
 380MODULE_DESCRIPTION("IBM Coherent Accelerator");
 381MODULE_AUTHOR("Ian Munsie <imunsie@au1.ibm.com>");
 382MODULE_LICENSE("GPL");
 383