arch/powerpc/platforms/powernv/vas-window.c

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This source file includes following definitions.
compute_paste_address
get_hvwc_mmio_bar
get_uwc_mmio_bar
map_paste_region
map_mmio_region
unmap_region
unmap_paste_region
unmap_winctx_mmio_bars
map_winctx_mmio_bars
reset_window_regs
init_xlate_regs
init_rsvd_tx_buf_count
init_winctx_regs
vas_release_window_id
vas_assign_window_id
vas_window_free
vas_window_alloc
put_rx_win
get_user_rxwin
get_vinst_rxwin
set_vinst_win
clear_vinst_win
init_winctx_for_rxwin
rx_win_args_valid
vas_init_rx_win_attr
vas_rx_win_open
vas_init_tx_win_attr
init_winctx_for_txwin
tx_win_args_valid
vas_tx_win_open
vas_copy_crb
vas_paste_crb
poll_window_credits
poll_window_busy_state
poll_window_castout
unpin_close_window
vas_win_close
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright 2016-17 IBM Corp.
   4  */
   5 
   6 #define pr_fmt(fmt) "vas: " fmt
   7 
   8 #include <linux/types.h>
   9 #include <linux/mutex.h>
  10 #include <linux/slab.h>
  11 #include <linux/io.h>
  12 #include <linux/log2.h>
  13 #include <linux/rcupdate.h>
  14 #include <linux/cred.h>
  15 #include <asm/switch_to.h>
  16 #include <asm/ppc-opcode.h>
  17 #include "vas.h"
  18 #include "copy-paste.h"
  19 
  20 #define CREATE_TRACE_POINTS
  21 #include "vas-trace.h"
  22 
  23 /*
  24  * Compute the paste address region for the window @window using the
  25  * ->paste_base_addr and ->paste_win_id_shift we got from device tree.
  26  */
  27 static void compute_paste_address(struct vas_window *window, u64 *addr, int *len)
  28 {
  29         int winid;
  30         u64 base, shift;
  31 
  32         base = window->vinst->paste_base_addr;
  33         shift = window->vinst->paste_win_id_shift;
  34         winid = window->winid;
  35 
  36         *addr  = base + (winid << shift);
  37         if (len)
  38                 *len = PAGE_SIZE;
  39 
  40         pr_debug("Txwin #%d: Paste addr 0x%llx\n", winid, *addr);
  41 }
  42 
  43 static inline void get_hvwc_mmio_bar(struct vas_window *window,
  44                         u64 *start, int *len)
  45 {
  46         u64 pbaddr;
  47 
  48         pbaddr = window->vinst->hvwc_bar_start;
  49         *start = pbaddr + window->winid * VAS_HVWC_SIZE;
  50         *len = VAS_HVWC_SIZE;
  51 }
  52 
  53 static inline void get_uwc_mmio_bar(struct vas_window *window,
  54                         u64 *start, int *len)
  55 {
  56         u64 pbaddr;
  57 
  58         pbaddr = window->vinst->uwc_bar_start;
  59         *start = pbaddr + window->winid * VAS_UWC_SIZE;
  60         *len = VAS_UWC_SIZE;
  61 }
  62 
  63 /*
  64  * Map the paste bus address of the given send window into kernel address
  65  * space. Unlike MMIO regions (map_mmio_region() below), paste region must
  66  * be mapped cache-able and is only applicable to send windows.
  67  */
  68 static void *map_paste_region(struct vas_window *txwin)
  69 {
  70         int len;
  71         void *map;
  72         char *name;
  73         u64 start;
  74 
  75         name = kasprintf(GFP_KERNEL, "window-v%d-w%d", txwin->vinst->vas_id,
  76                                 txwin->winid);
  77         if (!name)
  78                 goto free_name;
  79 
  80         txwin->paste_addr_name = name;
  81         compute_paste_address(txwin, &start, &len);
  82 
  83         if (!request_mem_region(start, len, name)) {
  84                 pr_devel("%s(): request_mem_region(0x%llx, %d) failed\n",
  85                                 __func__, start, len);
  86                 goto free_name;
  87         }
  88 
  89         map = ioremap_cache(start, len);
  90         if (!map) {
  91                 pr_devel("%s(): ioremap_cache(0x%llx, %d) failed\n", __func__,
  92                                 start, len);
  93                 goto free_name;
  94         }
  95 
  96         pr_devel("Mapped paste addr 0x%llx to kaddr 0x%p\n", start, map);
  97         return map;
  98 
  99 free_name:
 100         kfree(name);
 101         return ERR_PTR(-ENOMEM);
 102 }
 103 
 104 static void *map_mmio_region(char *name, u64 start, int len)
 105 {
 106         void *map;
 107 
 108         if (!request_mem_region(start, len, name)) {
 109                 pr_devel("%s(): request_mem_region(0x%llx, %d) failed\n",
 110                                 __func__, start, len);
 111                 return NULL;
 112         }
 113 
 114         map = ioremap(start, len);
 115         if (!map) {
 116                 pr_devel("%s(): ioremap(0x%llx, %d) failed\n", __func__, start,
 117                                 len);
 118                 return NULL;
 119         }
 120 
 121         return map;
 122 }
 123 
 124 static void unmap_region(void *addr, u64 start, int len)
 125 {
 126         iounmap(addr);
 127         release_mem_region((phys_addr_t)start, len);
 128 }
 129 
 130 /*
 131  * Unmap the paste address region for a window.
 132  */
 133 static void unmap_paste_region(struct vas_window *window)
 134 {
 135         int len;
 136         u64 busaddr_start;
 137 
 138         if (window->paste_kaddr) {
 139                 compute_paste_address(window, &busaddr_start, &len);
 140                 unmap_region(window->paste_kaddr, busaddr_start, len);
 141                 window->paste_kaddr = NULL;
 142                 kfree(window->paste_addr_name);
 143                 window->paste_addr_name = NULL;
 144         }
 145 }
 146 
 147 /*
 148  * Unmap the MMIO regions for a window. Hold the vas_mutex so we don't
 149  * unmap when the window's debugfs dir is in use. This serializes close
 150  * of a window even on another VAS instance but since its not a critical
 151  * path, just minimize the time we hold the mutex for now. We can add
 152  * a per-instance mutex later if necessary.
 153  */
 154 static void unmap_winctx_mmio_bars(struct vas_window *window)
 155 {
 156         int len;
 157         void *uwc_map;
 158         void *hvwc_map;
 159         u64 busaddr_start;
 160 
 161         mutex_lock(&vas_mutex);
 162 
 163         hvwc_map = window->hvwc_map;
 164         window->hvwc_map = NULL;
 165 
 166         uwc_map = window->uwc_map;
 167         window->uwc_map = NULL;
 168 
 169         mutex_unlock(&vas_mutex);
 170 
 171         if (hvwc_map) {
 172                 get_hvwc_mmio_bar(window, &busaddr_start, &len);
 173                 unmap_region(hvwc_map, busaddr_start, len);
 174         }
 175 
 176         if (uwc_map) {
 177                 get_uwc_mmio_bar(window, &busaddr_start, &len);
 178                 unmap_region(uwc_map, busaddr_start, len);
 179         }
 180 }
 181 
 182 /*
 183  * Find the Hypervisor Window Context (HVWC) MMIO Base Address Region and the
 184  * OS/User Window Context (UWC) MMIO Base Address Region for the given window.
 185  * Map these bus addresses and save the mapped kernel addresses in @window.
 186  */
 187 int map_winctx_mmio_bars(struct vas_window *window)
 188 {
 189         int len;
 190         u64 start;
 191 
 192         get_hvwc_mmio_bar(window, &start, &len);
 193         window->hvwc_map = map_mmio_region("HVWCM_Window", start, len);
 194 
 195         get_uwc_mmio_bar(window, &start, &len);
 196         window->uwc_map = map_mmio_region("UWCM_Window", start, len);
 197 
 198         if (!window->hvwc_map || !window->uwc_map) {
 199                 unmap_winctx_mmio_bars(window);
 200                 return -1;
 201         }
 202 
 203         return 0;
 204 }
 205 
 206 /*
 207  * Reset all valid registers in the HV and OS/User Window Contexts for
 208  * the window identified by @window.
 209  *
 210  * NOTE: We cannot really use a for loop to reset window context. Not all
 211  *       offsets in a window context are valid registers and the valid
 212  *       registers are not sequential. And, we can only write to offsets
 213  *       with valid registers.
 214  */
 215 void reset_window_regs(struct vas_window *window)
 216 {
 217         write_hvwc_reg(window, VREG(LPID), 0ULL);
 218         write_hvwc_reg(window, VREG(PID), 0ULL);
 219         write_hvwc_reg(window, VREG(XLATE_MSR), 0ULL);
 220         write_hvwc_reg(window, VREG(XLATE_LPCR), 0ULL);
 221         write_hvwc_reg(window, VREG(XLATE_CTL), 0ULL);
 222         write_hvwc_reg(window, VREG(AMR), 0ULL);
 223         write_hvwc_reg(window, VREG(SEIDR), 0ULL);
 224         write_hvwc_reg(window, VREG(FAULT_TX_WIN), 0ULL);
 225         write_hvwc_reg(window, VREG(OSU_INTR_SRC_RA), 0ULL);
 226         write_hvwc_reg(window, VREG(HV_INTR_SRC_RA), 0ULL);
 227         write_hvwc_reg(window, VREG(PSWID), 0ULL);
 228         write_hvwc_reg(window, VREG(LFIFO_BAR), 0ULL);
 229         write_hvwc_reg(window, VREG(LDATA_STAMP_CTL), 0ULL);
 230         write_hvwc_reg(window, VREG(LDMA_CACHE_CTL), 0ULL);
 231         write_hvwc_reg(window, VREG(LRFIFO_PUSH), 0ULL);
 232         write_hvwc_reg(window, VREG(CURR_MSG_COUNT), 0ULL);
 233         write_hvwc_reg(window, VREG(LNOTIFY_AFTER_COUNT), 0ULL);
 234         write_hvwc_reg(window, VREG(LRX_WCRED), 0ULL);
 235         write_hvwc_reg(window, VREG(LRX_WCRED_ADDER), 0ULL);
 236         write_hvwc_reg(window, VREG(TX_WCRED), 0ULL);
 237         write_hvwc_reg(window, VREG(TX_WCRED_ADDER), 0ULL);
 238         write_hvwc_reg(window, VREG(LFIFO_SIZE), 0ULL);
 239         write_hvwc_reg(window, VREG(WINCTL), 0ULL);
 240         write_hvwc_reg(window, VREG(WIN_STATUS), 0ULL);
 241         write_hvwc_reg(window, VREG(WIN_CTX_CACHING_CTL), 0ULL);
 242         write_hvwc_reg(window, VREG(TX_RSVD_BUF_COUNT), 0ULL);
 243         write_hvwc_reg(window, VREG(LRFIFO_WIN_PTR), 0ULL);
 244         write_hvwc_reg(window, VREG(LNOTIFY_CTL), 0ULL);
 245         write_hvwc_reg(window, VREG(LNOTIFY_PID), 0ULL);
 246         write_hvwc_reg(window, VREG(LNOTIFY_LPID), 0ULL);
 247         write_hvwc_reg(window, VREG(LNOTIFY_TID), 0ULL);
 248         write_hvwc_reg(window, VREG(LNOTIFY_SCOPE), 0ULL);
 249         write_hvwc_reg(window, VREG(NX_UTIL_ADDER), 0ULL);
 250 
 251         /* Skip read-only registers: NX_UTIL and NX_UTIL_SE */
 252 
 253         /*
 254          * The send and receive window credit adder registers are also
 255          * accessible from HVWC and have been initialized above. We don't
 256          * need to initialize from the OS/User Window Context, so skip
 257          * following calls:
 258          *
 259          *      write_uwc_reg(window, VREG(TX_WCRED_ADDER), 0ULL);
 260          *      write_uwc_reg(window, VREG(LRX_WCRED_ADDER), 0ULL);
 261          */
 262 }
 263 
 264 /*
 265  * Initialize window context registers related to Address Translation.
 266  * These registers are common to send/receive windows although they
 267  * differ for user/kernel windows. As we resolve the TODOs we may
 268  * want to add fields to vas_winctx and move the initialization to
 269  * init_vas_winctx_regs().
 270  */
 271 static void init_xlate_regs(struct vas_window *window, bool user_win)
 272 {
 273         u64 lpcr, val;
 274 
 275         /*
 276          * MSR_TA, MSR_US are false for both kernel and user.
 277          * MSR_DR and MSR_PR are false for kernel.
 278          */
 279         val = 0ULL;
 280         val = SET_FIELD(VAS_XLATE_MSR_HV, val, 1);
 281         val = SET_FIELD(VAS_XLATE_MSR_SF, val, 1);
 282         if (user_win) {
 283                 val = SET_FIELD(VAS_XLATE_MSR_DR, val, 1);
 284                 val = SET_FIELD(VAS_XLATE_MSR_PR, val, 1);
 285         }
 286         write_hvwc_reg(window, VREG(XLATE_MSR), val);
 287 
 288         lpcr = mfspr(SPRN_LPCR);
 289         val = 0ULL;
 290         /*
 291          * NOTE: From Section 5.7.8.1 Segment Lookaside Buffer of the
 292          *       Power ISA, v3.0B, Page size encoding is 0 = 4KB, 5 = 64KB.
 293          *
 294          * NOTE: From Section 1.3.1, Address Translation Context of the
 295          *       Nest MMU Workbook, LPCR_SC should be 0 for Power9.
 296          */
 297         val = SET_FIELD(VAS_XLATE_LPCR_PAGE_SIZE, val, 5);
 298         val = SET_FIELD(VAS_XLATE_LPCR_ISL, val, lpcr & LPCR_ISL);
 299         val = SET_FIELD(VAS_XLATE_LPCR_TC, val, lpcr & LPCR_TC);
 300         val = SET_FIELD(VAS_XLATE_LPCR_SC, val, 0);
 301         write_hvwc_reg(window, VREG(XLATE_LPCR), val);
 302 
 303         /*
 304          * Section 1.3.1 (Address translation Context) of NMMU workbook.
 305          *      0b00    Hashed Page Table mode
 306          *      0b01    Reserved
 307          *      0b10    Radix on HPT
 308          *      0b11    Radix on Radix
 309          */
 310         val = 0ULL;
 311         val = SET_FIELD(VAS_XLATE_MODE, val, radix_enabled() ? 3 : 2);
 312         write_hvwc_reg(window, VREG(XLATE_CTL), val);
 313 
 314         /*
 315          * TODO: Can we mfspr(AMR) even for user windows?
 316          */
 317         val = 0ULL;
 318         val = SET_FIELD(VAS_AMR, val, mfspr(SPRN_AMR));
 319         write_hvwc_reg(window, VREG(AMR), val);
 320 
 321         val = 0ULL;
 322         val = SET_FIELD(VAS_SEIDR, val, 0);
 323         write_hvwc_reg(window, VREG(SEIDR), val);
 324 }
 325 
 326 /*
 327  * Initialize Reserved Send Buffer Count for the send window. It involves
 328  * writing to the register, reading it back to confirm that the hardware
 329  * has enough buffers to reserve. See section 1.3.1.2.1 of VAS workbook.
 330  *
 331  * Since we can only make a best-effort attempt to fulfill the request,
 332  * we don't return any errors if we cannot.
 333  *
 334  * TODO: Reserved (aka dedicated) send buffers are not supported yet.
 335  */
 336 static void init_rsvd_tx_buf_count(struct vas_window *txwin,
 337                                 struct vas_winctx *winctx)
 338 {
 339         write_hvwc_reg(txwin, VREG(TX_RSVD_BUF_COUNT), 0ULL);
 340 }
 341 
 342 /*
 343  * init_winctx_regs()
 344  *      Initialize window context registers for a receive window.
 345  *      Except for caching control and marking window open, the registers
 346  *      are initialized in the order listed in Section 3.1.4 (Window Context
 347  *      Cache Register Details) of the VAS workbook although they don't need
 348  *      to be.
 349  *
 350  * Design note: For NX receive windows, NX allocates the FIFO buffer in OPAL
 351  *      (so that it can get a large contiguous area) and passes that buffer
 352  *      to kernel via device tree. We now write that buffer address to the
 353  *      FIFO BAR. Would it make sense to do this all in OPAL? i.e have OPAL
 354  *      write the per-chip RX FIFO addresses to the windows during boot-up
 355  *      as a one-time task? That could work for NX but what about other
 356  *      receivers?  Let the receivers tell us the rx-fifo buffers for now.
 357  */
 358 int init_winctx_regs(struct vas_window *window, struct vas_winctx *winctx)
 359 {
 360         u64 val;
 361         int fifo_size;
 362 
 363         reset_window_regs(window);
 364 
 365         val = 0ULL;
 366         val = SET_FIELD(VAS_LPID, val, winctx->lpid);
 367         write_hvwc_reg(window, VREG(LPID), val);
 368 
 369         val = 0ULL;
 370         val = SET_FIELD(VAS_PID_ID, val, winctx->pidr);
 371         write_hvwc_reg(window, VREG(PID), val);
 372 
 373         init_xlate_regs(window, winctx->user_win);
 374 
 375         val = 0ULL;
 376         val = SET_FIELD(VAS_FAULT_TX_WIN, val, 0);
 377         write_hvwc_reg(window, VREG(FAULT_TX_WIN), val);
 378 
 379         /* In PowerNV, interrupts go to HV. */
 380         write_hvwc_reg(window, VREG(OSU_INTR_SRC_RA), 0ULL);
 381 
 382         val = 0ULL;
 383         val = SET_FIELD(VAS_HV_INTR_SRC_RA, val, winctx->irq_port);
 384         write_hvwc_reg(window, VREG(HV_INTR_SRC_RA), val);
 385 
 386         val = 0ULL;
 387         val = SET_FIELD(VAS_PSWID_EA_HANDLE, val, winctx->pswid);
 388         write_hvwc_reg(window, VREG(PSWID), val);
 389 
 390         write_hvwc_reg(window, VREG(SPARE1), 0ULL);
 391         write_hvwc_reg(window, VREG(SPARE2), 0ULL);
 392         write_hvwc_reg(window, VREG(SPARE3), 0ULL);
 393 
 394         /*
 395          * NOTE: VAS expects the FIFO address to be copied into the LFIFO_BAR
 396          *       register as is - do NOT shift the address into VAS_LFIFO_BAR
 397          *       bit fields! Ok to set the page migration select fields -
 398          *       VAS ignores the lower 10+ bits in the address anyway, because
 399          *       the minimum FIFO size is 1K?
 400          *
 401          * See also: Design note in function header.
 402          */
 403         val = __pa(winctx->rx_fifo);
 404         val = SET_FIELD(VAS_PAGE_MIGRATION_SELECT, val, 0);
 405         write_hvwc_reg(window, VREG(LFIFO_BAR), val);
 406 
 407         val = 0ULL;
 408         val = SET_FIELD(VAS_LDATA_STAMP, val, winctx->data_stamp);
 409         write_hvwc_reg(window, VREG(LDATA_STAMP_CTL), val);
 410 
 411         val = 0ULL;
 412         val = SET_FIELD(VAS_LDMA_TYPE, val, winctx->dma_type);
 413         val = SET_FIELD(VAS_LDMA_FIFO_DISABLE, val, winctx->fifo_disable);
 414         write_hvwc_reg(window, VREG(LDMA_CACHE_CTL), val);
 415 
 416         write_hvwc_reg(window, VREG(LRFIFO_PUSH), 0ULL);
 417         write_hvwc_reg(window, VREG(CURR_MSG_COUNT), 0ULL);
 418         write_hvwc_reg(window, VREG(LNOTIFY_AFTER_COUNT), 0ULL);
 419 
 420         val = 0ULL;
 421         val = SET_FIELD(VAS_LRX_WCRED, val, winctx->wcreds_max);
 422         write_hvwc_reg(window, VREG(LRX_WCRED), val);
 423 
 424         val = 0ULL;
 425         val = SET_FIELD(VAS_TX_WCRED, val, winctx->wcreds_max);
 426         write_hvwc_reg(window, VREG(TX_WCRED), val);
 427 
 428         write_hvwc_reg(window, VREG(LRX_WCRED_ADDER), 0ULL);
 429         write_hvwc_reg(window, VREG(TX_WCRED_ADDER), 0ULL);
 430 
 431         fifo_size = winctx->rx_fifo_size / 1024;
 432 
 433         val = 0ULL;
 434         val = SET_FIELD(VAS_LFIFO_SIZE, val, ilog2(fifo_size));
 435         write_hvwc_reg(window, VREG(LFIFO_SIZE), val);
 436 
 437         /* Update window control and caching control registers last so
 438          * we mark the window open only after fully initializing it and
 439          * pushing context to cache.
 440          */
 441 
 442         write_hvwc_reg(window, VREG(WIN_STATUS), 0ULL);
 443 
 444         init_rsvd_tx_buf_count(window, winctx);
 445 
 446         /* for a send window, point to the matching receive window */
 447         val = 0ULL;
 448         val = SET_FIELD(VAS_LRX_WIN_ID, val, winctx->rx_win_id);
 449         write_hvwc_reg(window, VREG(LRFIFO_WIN_PTR), val);
 450 
 451         write_hvwc_reg(window, VREG(SPARE4), 0ULL);
 452 
 453         val = 0ULL;
 454         val = SET_FIELD(VAS_NOTIFY_DISABLE, val, winctx->notify_disable);
 455         val = SET_FIELD(VAS_INTR_DISABLE, val, winctx->intr_disable);
 456         val = SET_FIELD(VAS_NOTIFY_EARLY, val, winctx->notify_early);
 457         val = SET_FIELD(VAS_NOTIFY_OSU_INTR, val, winctx->notify_os_intr_reg);
 458         write_hvwc_reg(window, VREG(LNOTIFY_CTL), val);
 459 
 460         val = 0ULL;
 461         val = SET_FIELD(VAS_LNOTIFY_PID, val, winctx->lnotify_pid);
 462         write_hvwc_reg(window, VREG(LNOTIFY_PID), val);
 463 
 464         val = 0ULL;
 465         val = SET_FIELD(VAS_LNOTIFY_LPID, val, winctx->lnotify_lpid);
 466         write_hvwc_reg(window, VREG(LNOTIFY_LPID), val);
 467 
 468         val = 0ULL;
 469         val = SET_FIELD(VAS_LNOTIFY_TID, val, winctx->lnotify_tid);
 470         write_hvwc_reg(window, VREG(LNOTIFY_TID), val);
 471 
 472         val = 0ULL;
 473         val = SET_FIELD(VAS_LNOTIFY_MIN_SCOPE, val, winctx->min_scope);
 474         val = SET_FIELD(VAS_LNOTIFY_MAX_SCOPE, val, winctx->max_scope);
 475         write_hvwc_reg(window, VREG(LNOTIFY_SCOPE), val);
 476 
 477         /* Skip read-only registers NX_UTIL and NX_UTIL_SE */
 478 
 479         write_hvwc_reg(window, VREG(SPARE5), 0ULL);
 480         write_hvwc_reg(window, VREG(NX_UTIL_ADDER), 0ULL);
 481         write_hvwc_reg(window, VREG(SPARE6), 0ULL);
 482 
 483         /* Finally, push window context to memory and... */
 484         val = 0ULL;
 485         val = SET_FIELD(VAS_PUSH_TO_MEM, val, 1);
 486         write_hvwc_reg(window, VREG(WIN_CTX_CACHING_CTL), val);
 487 
 488         /* ... mark the window open for business */
 489         val = 0ULL;
 490         val = SET_FIELD(VAS_WINCTL_REJ_NO_CREDIT, val, winctx->rej_no_credit);
 491         val = SET_FIELD(VAS_WINCTL_PIN, val, winctx->pin_win);
 492         val = SET_FIELD(VAS_WINCTL_TX_WCRED_MODE, val, winctx->tx_wcred_mode);
 493         val = SET_FIELD(VAS_WINCTL_RX_WCRED_MODE, val, winctx->rx_wcred_mode);
 494         val = SET_FIELD(VAS_WINCTL_TX_WORD_MODE, val, winctx->tx_word_mode);
 495         val = SET_FIELD(VAS_WINCTL_RX_WORD_MODE, val, winctx->rx_word_mode);
 496         val = SET_FIELD(VAS_WINCTL_FAULT_WIN, val, winctx->fault_win);
 497         val = SET_FIELD(VAS_WINCTL_NX_WIN, val, winctx->nx_win);
 498         val = SET_FIELD(VAS_WINCTL_OPEN, val, 1);
 499         write_hvwc_reg(window, VREG(WINCTL), val);
 500 
 501         return 0;
 502 }
 503 
 504 static void vas_release_window_id(struct ida *ida, int winid)
 505 {
 506         ida_free(ida, winid);
 507 }
 508 
 509 static int vas_assign_window_id(struct ida *ida)
 510 {
 511         int winid = ida_alloc_max(ida, VAS_WINDOWS_PER_CHIP - 1, GFP_KERNEL);
 512 
 513         if (winid == -ENOSPC) {
 514                 pr_err("Too many (%d) open windows\n", VAS_WINDOWS_PER_CHIP);
 515                 return -EAGAIN;
 516         }
 517 
 518         return winid;
 519 }
 520 
 521 static void vas_window_free(struct vas_window *window)
 522 {
 523         int winid = window->winid;
 524         struct vas_instance *vinst = window->vinst;
 525 
 526         unmap_winctx_mmio_bars(window);
 527 
 528         vas_window_free_dbgdir(window);
 529 
 530         kfree(window);
 531 
 532         vas_release_window_id(&vinst->ida, winid);
 533 }
 534 
 535 static struct vas_window *vas_window_alloc(struct vas_instance *vinst)
 536 {
 537         int winid;
 538         struct vas_window *window;
 539 
 540         winid = vas_assign_window_id(&vinst->ida);
 541         if (winid < 0)
 542                 return ERR_PTR(winid);
 543 
 544         window = kzalloc(sizeof(*window), GFP_KERNEL);
 545         if (!window)
 546                 goto out_free;
 547 
 548         window->vinst = vinst;
 549         window->winid = winid;
 550 
 551         if (map_winctx_mmio_bars(window))
 552                 goto out_free;
 553 
 554         vas_window_init_dbgdir(window);
 555 
 556         return window;
 557 
 558 out_free:
 559         kfree(window);
 560         vas_release_window_id(&vinst->ida, winid);
 561         return ERR_PTR(-ENOMEM);
 562 }
 563 
 564 static void put_rx_win(struct vas_window *rxwin)
 565 {
 566         /* Better not be a send window! */
 567         WARN_ON_ONCE(rxwin->tx_win);
 568 
 569         atomic_dec(&rxwin->num_txwins);
 570 }
 571 
 572 /*
 573  * Find the user space receive window given the @pswid.
 574  *      - We must have a valid vasid and it must belong to this instance.
 575  *        (so both send and receive windows are on the same VAS instance)
 576  *      - The window must refer to an OPEN, FTW, RECEIVE window.
 577  *
 578  * NOTE: We access ->windows[] table and assume that vinst->mutex is held.
 579  */
 580 static struct vas_window *get_user_rxwin(struct vas_instance *vinst, u32 pswid)
 581 {
 582         int vasid, winid;
 583         struct vas_window *rxwin;
 584 
 585         decode_pswid(pswid, &vasid, &winid);
 586 
 587         if (vinst->vas_id != vasid)
 588                 return ERR_PTR(-EINVAL);
 589 
 590         rxwin = vinst->windows[winid];
 591 
 592         if (!rxwin || rxwin->tx_win || rxwin->cop != VAS_COP_TYPE_FTW)
 593                 return ERR_PTR(-EINVAL);
 594 
 595         return rxwin;
 596 }
 597 
 598 /*
 599  * Get the VAS receive window associated with NX engine identified
 600  * by @cop and if applicable, @pswid.
 601  *
 602  * See also function header of set_vinst_win().
 603  */
 604 static struct vas_window *get_vinst_rxwin(struct vas_instance *vinst,
 605                         enum vas_cop_type cop, u32 pswid)
 606 {
 607         struct vas_window *rxwin;
 608 
 609         mutex_lock(&vinst->mutex);
 610 
 611         if (cop == VAS_COP_TYPE_FTW)
 612                 rxwin = get_user_rxwin(vinst, pswid);
 613         else
 614                 rxwin = vinst->rxwin[cop] ?: ERR_PTR(-EINVAL);
 615 
 616         if (!IS_ERR(rxwin))
 617                 atomic_inc(&rxwin->num_txwins);
 618 
 619         mutex_unlock(&vinst->mutex);
 620 
 621         return rxwin;
 622 }
 623 
 624 /*
 625  * We have two tables of windows in a VAS instance. The first one,
 626  * ->windows[], contains all the windows in the instance and allows
 627  * looking up a window by its id. It is used to look up send windows
 628  * during fault handling and receive windows when pairing user space
 629  * send/receive windows.
 630  *
 631  * The second table, ->rxwin[], contains receive windows that are
 632  * associated with NX engines. This table has VAS_COP_TYPE_MAX
 633  * entries and is used to look up a receive window by its
 634  * coprocessor type.
 635  *
 636  * Here, we save @window in the ->windows[] table. If it is a receive
 637  * window, we also save the window in the ->rxwin[] table.
 638  */
 639 static void set_vinst_win(struct vas_instance *vinst,
 640                         struct vas_window *window)
 641 {
 642         int id = window->winid;
 643 
 644         mutex_lock(&vinst->mutex);
 645 
 646         /*
 647          * There should only be one receive window for a coprocessor type
 648          * unless its a user (FTW) window.
 649          */
 650         if (!window->user_win && !window->tx_win) {
 651                 WARN_ON_ONCE(vinst->rxwin[window->cop]);
 652                 vinst->rxwin[window->cop] = window;
 653         }
 654 
 655         WARN_ON_ONCE(vinst->windows[id] != NULL);
 656         vinst->windows[id] = window;
 657 
 658         mutex_unlock(&vinst->mutex);
 659 }
 660 
 661 /*
 662  * Clear this window from the table(s) of windows for this VAS instance.
 663  * See also function header of set_vinst_win().
 664  */
 665 static void clear_vinst_win(struct vas_window *window)
 666 {
 667         int id = window->winid;
 668         struct vas_instance *vinst = window->vinst;
 669 
 670         mutex_lock(&vinst->mutex);
 671 
 672         if (!window->user_win && !window->tx_win) {
 673                 WARN_ON_ONCE(!vinst->rxwin[window->cop]);
 674                 vinst->rxwin[window->cop] = NULL;
 675         }
 676 
 677         WARN_ON_ONCE(vinst->windows[id] != window);
 678         vinst->windows[id] = NULL;
 679 
 680         mutex_unlock(&vinst->mutex);
 681 }
 682 
 683 static void init_winctx_for_rxwin(struct vas_window *rxwin,
 684                         struct vas_rx_win_attr *rxattr,
 685                         struct vas_winctx *winctx)
 686 {
 687         /*
 688          * We first zero (memset()) all fields and only set non-zero fields.
 689          * Following fields are 0/false but maybe deserve a comment:
 690          *
 691          *      ->notify_os_intr_reg    In powerNV, send intrs to HV
 692          *      ->notify_disable        False for NX windows
 693          *      ->intr_disable          False for Fault Windows
 694          *      ->xtra_write            False for NX windows
 695          *      ->notify_early          NA for NX windows
 696          *      ->rsvd_txbuf_count      NA for Rx windows
 697          *      ->lpid, ->pid, ->tid    NA for Rx windows
 698          */
 699 
 700         memset(winctx, 0, sizeof(struct vas_winctx));
 701 
 702         winctx->rx_fifo = rxattr->rx_fifo;
 703         winctx->rx_fifo_size = rxattr->rx_fifo_size;
 704         winctx->wcreds_max = rxwin->wcreds_max;
 705         winctx->pin_win = rxattr->pin_win;
 706 
 707         winctx->nx_win = rxattr->nx_win;
 708         winctx->fault_win = rxattr->fault_win;
 709         winctx->user_win = rxattr->user_win;
 710         winctx->rej_no_credit = rxattr->rej_no_credit;
 711         winctx->rx_word_mode = rxattr->rx_win_ord_mode;
 712         winctx->tx_word_mode = rxattr->tx_win_ord_mode;
 713         winctx->rx_wcred_mode = rxattr->rx_wcred_mode;
 714         winctx->tx_wcred_mode = rxattr->tx_wcred_mode;
 715         winctx->notify_early = rxattr->notify_early;
 716 
 717         if (winctx->nx_win) {
 718                 winctx->data_stamp = true;
 719                 winctx->intr_disable = true;
 720                 winctx->pin_win = true;
 721 
 722                 WARN_ON_ONCE(winctx->fault_win);
 723                 WARN_ON_ONCE(!winctx->rx_word_mode);
 724                 WARN_ON_ONCE(!winctx->tx_word_mode);
 725                 WARN_ON_ONCE(winctx->notify_after_count);
 726         } else if (winctx->fault_win) {
 727                 winctx->notify_disable = true;
 728         } else if (winctx->user_win) {
 729                 /*
 730                  * Section 1.8.1 Low Latency Core-Core Wake up of
 731                  * the VAS workbook:
 732                  *
 733                  *      - disable credit checks ([tr]x_wcred_mode = false)
 734                  *      - disable FIFO writes
 735                  *      - enable ASB_Notify, disable interrupt
 736                  */
 737                 winctx->fifo_disable = true;
 738                 winctx->intr_disable = true;
 739                 winctx->rx_fifo = NULL;
 740         }
 741 
 742         winctx->lnotify_lpid = rxattr->lnotify_lpid;
 743         winctx->lnotify_pid = rxattr->lnotify_pid;
 744         winctx->lnotify_tid = rxattr->lnotify_tid;
 745         winctx->pswid = rxattr->pswid;
 746         winctx->dma_type = VAS_DMA_TYPE_INJECT;
 747         winctx->tc_mode = rxattr->tc_mode;
 748 
 749         winctx->min_scope = VAS_SCOPE_LOCAL;
 750         winctx->max_scope = VAS_SCOPE_VECTORED_GROUP;
 751 }
 752 
 753 static bool rx_win_args_valid(enum vas_cop_type cop,
 754                         struct vas_rx_win_attr *attr)
 755 {
 756         pr_debug("Rxattr: fault %d, notify %d, intr %d, early %d, fifo %d\n",
 757                         attr->fault_win, attr->notify_disable,
 758                         attr->intr_disable, attr->notify_early,
 759                         attr->rx_fifo_size);
 760 
 761         if (cop >= VAS_COP_TYPE_MAX)
 762                 return false;
 763 
 764         if (cop != VAS_COP_TYPE_FTW &&
 765                                 attr->rx_fifo_size < VAS_RX_FIFO_SIZE_MIN)
 766                 return false;
 767 
 768         if (attr->rx_fifo_size > VAS_RX_FIFO_SIZE_MAX)
 769                 return false;
 770 
 771         if (attr->wcreds_max > VAS_RX_WCREDS_MAX)
 772                 return false;
 773 
 774         if (attr->nx_win) {
 775                 /* cannot be fault or user window if it is nx */
 776                 if (attr->fault_win || attr->user_win)
 777                         return false;
 778                 /*
 779                  * Section 3.1.4.32: NX Windows must not disable notification,
 780                  *      and must not enable interrupts or early notification.
 781                  */
 782                 if (attr->notify_disable || !attr->intr_disable ||
 783                                 attr->notify_early)
 784                         return false;
 785         } else if (attr->fault_win) {
 786                 /* cannot be both fault and user window */
 787                 if (attr->user_win)
 788                         return false;
 789 
 790                 /*
 791                  * Section 3.1.4.32: Fault windows must disable notification
 792                  *      but not interrupts.
 793                  */
 794                 if (!attr->notify_disable || attr->intr_disable)
 795                         return false;
 796 
 797         } else if (attr->user_win) {
 798                 /*
 799                  * User receive windows are only for fast-thread-wakeup
 800                  * (FTW). They don't need a FIFO and must disable interrupts
 801                  */
 802                 if (attr->rx_fifo || attr->rx_fifo_size || !attr->intr_disable)
 803                         return false;
 804         } else {
 805                 /* Rx window must be one of NX or Fault or User window. */
 806                 return false;
 807         }
 808 
 809         return true;
 810 }
 811 
 812 void vas_init_rx_win_attr(struct vas_rx_win_attr *rxattr, enum vas_cop_type cop)
 813 {
 814         memset(rxattr, 0, sizeof(*rxattr));
 815 
 816         if (cop == VAS_COP_TYPE_842 || cop == VAS_COP_TYPE_842_HIPRI) {
 817                 rxattr->pin_win = true;
 818                 rxattr->nx_win = true;
 819                 rxattr->fault_win = false;
 820                 rxattr->intr_disable = true;
 821                 rxattr->rx_wcred_mode = true;
 822                 rxattr->tx_wcred_mode = true;
 823                 rxattr->rx_win_ord_mode = true;
 824                 rxattr->tx_win_ord_mode = true;
 825         } else if (cop == VAS_COP_TYPE_FAULT) {
 826                 rxattr->pin_win = true;
 827                 rxattr->fault_win = true;
 828                 rxattr->notify_disable = true;
 829                 rxattr->rx_wcred_mode = true;
 830                 rxattr->tx_wcred_mode = true;
 831                 rxattr->rx_win_ord_mode = true;
 832                 rxattr->tx_win_ord_mode = true;
 833         } else if (cop == VAS_COP_TYPE_FTW) {
 834                 rxattr->user_win = true;
 835                 rxattr->intr_disable = true;
 836 
 837                 /*
 838                  * As noted in the VAS Workbook we disable credit checks.
 839                  * If we enable credit checks in the future, we must also
 840                  * implement a mechanism to return the user credits or new
 841                  * paste operations will fail.
 842                  */
 843         }
 844 }
 845 EXPORT_SYMBOL_GPL(vas_init_rx_win_attr);
 846 
 847 struct vas_window *vas_rx_win_open(int vasid, enum vas_cop_type cop,
 848                         struct vas_rx_win_attr *rxattr)
 849 {
 850         struct vas_window *rxwin;
 851         struct vas_winctx winctx;
 852         struct vas_instance *vinst;
 853 
 854         trace_vas_rx_win_open(current, vasid, cop, rxattr);
 855 
 856         if (!rx_win_args_valid(cop, rxattr))
 857                 return ERR_PTR(-EINVAL);
 858 
 859         vinst = find_vas_instance(vasid);
 860         if (!vinst) {
 861                 pr_devel("vasid %d not found!\n", vasid);
 862                 return ERR_PTR(-EINVAL);
 863         }
 864         pr_devel("Found instance %d\n", vasid);
 865 
 866         rxwin = vas_window_alloc(vinst);
 867         if (IS_ERR(rxwin)) {
 868                 pr_devel("Unable to allocate memory for Rx window\n");
 869                 return rxwin;
 870         }
 871 
 872         rxwin->tx_win = false;
 873         rxwin->nx_win = rxattr->nx_win;
 874         rxwin->user_win = rxattr->user_win;
 875         rxwin->cop = cop;
 876         rxwin->wcreds_max = rxattr->wcreds_max ?: VAS_WCREDS_DEFAULT;
 877         if (rxattr->user_win)
 878                 rxwin->pid = task_pid_vnr(current);
 879 
 880         init_winctx_for_rxwin(rxwin, rxattr, &winctx);
 881         init_winctx_regs(rxwin, &winctx);
 882 
 883         set_vinst_win(vinst, rxwin);
 884 
 885         return rxwin;
 886 }
 887 EXPORT_SYMBOL_GPL(vas_rx_win_open);
 888 
 889 void vas_init_tx_win_attr(struct vas_tx_win_attr *txattr, enum vas_cop_type cop)
 890 {
 891         memset(txattr, 0, sizeof(*txattr));
 892 
 893         if (cop == VAS_COP_TYPE_842 || cop == VAS_COP_TYPE_842_HIPRI) {
 894                 txattr->rej_no_credit = false;
 895                 txattr->rx_wcred_mode = true;
 896                 txattr->tx_wcred_mode = true;
 897                 txattr->rx_win_ord_mode = true;
 898                 txattr->tx_win_ord_mode = true;
 899         } else if (cop == VAS_COP_TYPE_FTW) {
 900                 txattr->user_win = true;
 901         }
 902 }
 903 EXPORT_SYMBOL_GPL(vas_init_tx_win_attr);
 904 
 905 static void init_winctx_for_txwin(struct vas_window *txwin,
 906                         struct vas_tx_win_attr *txattr,
 907                         struct vas_winctx *winctx)
 908 {
 909         /*
 910          * We first zero all fields and only set non-zero ones. Following
 911          * are some fields set to 0/false for the stated reason:
 912          *
 913          *      ->notify_os_intr_reg    In powernv, send intrs to HV
 914          *      ->rsvd_txbuf_count      Not supported yet.
 915          *      ->notify_disable        False for NX windows
 916          *      ->xtra_write            False for NX windows
 917          *      ->notify_early          NA for NX windows
 918          *      ->lnotify_lpid          NA for Tx windows
 919          *      ->lnotify_pid           NA for Tx windows
 920          *      ->lnotify_tid           NA for Tx windows
 921          *      ->tx_win_cred_mode      Ignore for now for NX windows
 922          *      ->rx_win_cred_mode      Ignore for now for NX windows
 923          */
 924         memset(winctx, 0, sizeof(struct vas_winctx));
 925 
 926         winctx->wcreds_max = txwin->wcreds_max;
 927 
 928         winctx->user_win = txattr->user_win;
 929         winctx->nx_win = txwin->rxwin->nx_win;
 930         winctx->pin_win = txattr->pin_win;
 931         winctx->rej_no_credit = txattr->rej_no_credit;
 932         winctx->rsvd_txbuf_enable = txattr->rsvd_txbuf_enable;
 933 
 934         winctx->rx_wcred_mode = txattr->rx_wcred_mode;
 935         winctx->tx_wcred_mode = txattr->tx_wcred_mode;
 936         winctx->rx_word_mode = txattr->rx_win_ord_mode;
 937         winctx->tx_word_mode = txattr->tx_win_ord_mode;
 938         winctx->rsvd_txbuf_count = txattr->rsvd_txbuf_count;
 939 
 940         winctx->intr_disable = true;
 941         if (winctx->nx_win)
 942                 winctx->data_stamp = true;
 943 
 944         winctx->lpid = txattr->lpid;
 945         winctx->pidr = txattr->pidr;
 946         winctx->rx_win_id = txwin->rxwin->winid;
 947 
 948         winctx->dma_type = VAS_DMA_TYPE_INJECT;
 949         winctx->tc_mode = txattr->tc_mode;
 950         winctx->min_scope = VAS_SCOPE_LOCAL;
 951         winctx->max_scope = VAS_SCOPE_VECTORED_GROUP;
 952 
 953         winctx->pswid = 0;
 954 }
 955 
 956 static bool tx_win_args_valid(enum vas_cop_type cop,
 957                         struct vas_tx_win_attr *attr)
 958 {
 959         if (attr->tc_mode != VAS_THRESH_DISABLED)
 960                 return false;
 961 
 962         if (cop > VAS_COP_TYPE_MAX)
 963                 return false;
 964 
 965         if (attr->wcreds_max > VAS_TX_WCREDS_MAX)
 966                 return false;
 967 
 968         if (attr->user_win &&
 969                         (cop != VAS_COP_TYPE_FTW || attr->rsvd_txbuf_count))
 970                 return false;
 971 
 972         return true;
 973 }
 974 
 975 struct vas_window *vas_tx_win_open(int vasid, enum vas_cop_type cop,
 976                         struct vas_tx_win_attr *attr)
 977 {
 978         int rc;
 979         struct vas_window *txwin;
 980         struct vas_window *rxwin;
 981         struct vas_winctx winctx;
 982         struct vas_instance *vinst;
 983 
 984         trace_vas_tx_win_open(current, vasid, cop, attr);
 985 
 986         if (!tx_win_args_valid(cop, attr))
 987                 return ERR_PTR(-EINVAL);
 988 
 989         /*
 990          * If caller did not specify a vasid but specified the PSWID of a
 991          * receive window (applicable only to FTW windows), use the vasid
 992          * from that receive window.
 993          */
 994         if (vasid == -1 && attr->pswid)
 995                 decode_pswid(attr->pswid, &vasid, NULL);
 996 
 997         vinst = find_vas_instance(vasid);
 998         if (!vinst) {
 999                 pr_devel("vasid %d not found!\n", vasid);
1000                 return ERR_PTR(-EINVAL);
1001         }
1002 
1003         rxwin = get_vinst_rxwin(vinst, cop, attr->pswid);
1004         if (IS_ERR(rxwin)) {
1005                 pr_devel("No RxWin for vasid %d, cop %d\n", vasid, cop);
1006                 return rxwin;
1007         }
1008 
1009         txwin = vas_window_alloc(vinst);
1010         if (IS_ERR(txwin)) {
1011                 rc = PTR_ERR(txwin);
1012                 goto put_rxwin;
1013         }
1014 
1015         txwin->cop = cop;
1016         txwin->tx_win = 1;
1017         txwin->rxwin = rxwin;
1018         txwin->nx_win = txwin->rxwin->nx_win;
1019         txwin->pid = attr->pid;
1020         txwin->user_win = attr->user_win;
1021         txwin->wcreds_max = attr->wcreds_max ?: VAS_WCREDS_DEFAULT;
1022 
1023         init_winctx_for_txwin(txwin, attr, &winctx);
1024 
1025         init_winctx_regs(txwin, &winctx);
1026 
1027         /*
1028          * If its a kernel send window, map the window address into the
1029          * kernel's address space. For user windows, user must issue an
1030          * mmap() to map the window into their address space.
1031          *
1032          * NOTE: If kernel ever resubmits a user CRB after handling a page
1033          *       fault, we will need to map this into kernel as well.
1034          */
1035         if (!txwin->user_win) {
1036                 txwin->paste_kaddr = map_paste_region(txwin);
1037                 if (IS_ERR(txwin->paste_kaddr)) {
1038                         rc = PTR_ERR(txwin->paste_kaddr);
1039                         goto free_window;
1040                 }
1041         } else {
1042                 /*
1043                  * A user mapping must ensure that context switch issues
1044                  * CP_ABORT for this thread.
1045                  */
1046                 rc = set_thread_uses_vas();
1047                 if (rc)
1048                         goto free_window;
1049         }
1050 
1051         set_vinst_win(vinst, txwin);
1052 
1053         return txwin;
1054 
1055 free_window:
1056         vas_window_free(txwin);
1057 
1058 put_rxwin:
1059         put_rx_win(rxwin);
1060         return ERR_PTR(rc);
1061 
1062 }
1063 EXPORT_SYMBOL_GPL(vas_tx_win_open);
1064 
1065 int vas_copy_crb(void *crb, int offset)
1066 {
1067         return vas_copy(crb, offset);
1068 }
1069 EXPORT_SYMBOL_GPL(vas_copy_crb);
1070 
1071 #define RMA_LSMP_REPORT_ENABLE PPC_BIT(53)
1072 int vas_paste_crb(struct vas_window *txwin, int offset, bool re)
1073 {
1074         int rc;
1075         void *addr;
1076         uint64_t val;
1077 
1078         trace_vas_paste_crb(current, txwin);
1079 
1080         /*
1081          * Only NX windows are supported for now and hardware assumes
1082          * report-enable flag is set for NX windows. Ensure software
1083          * complies too.
1084          */
1085         WARN_ON_ONCE(txwin->nx_win && !re);
1086 
1087         addr = txwin->paste_kaddr;
1088         if (re) {
1089                 /*
1090                  * Set the REPORT_ENABLE bit (equivalent to writing
1091                  * to 1K offset of the paste address)
1092                  */
1093                 val = SET_FIELD(RMA_LSMP_REPORT_ENABLE, 0ULL, 1);
1094                 addr += val;
1095         }
1096 
1097         /*
1098          * Map the raw CR value from vas_paste() to an error code (there
1099          * is just pass or fail for now though).
1100          */
1101         rc = vas_paste(addr, offset);
1102         if (rc == 2)
1103                 rc = 0;
1104         else
1105                 rc = -EINVAL;
1106 
1107         pr_debug("Txwin #%d: Msg count %llu\n", txwin->winid,
1108                         read_hvwc_reg(txwin, VREG(LRFIFO_PUSH)));
1109 
1110         return rc;
1111 }
1112 EXPORT_SYMBOL_GPL(vas_paste_crb);
1113 
1114 /*
1115  * If credit checking is enabled for this window, poll for the return
1116  * of window credits (i.e for NX engines to process any outstanding CRBs).
1117  * Since NX-842 waits for the CRBs to be processed before closing the
1118  * window, we should not have to wait for too long.
1119  *
1120  * TODO: We retry in 10ms intervals now. We could/should probably peek at
1121  *      the VAS_LRFIFO_PUSH_OFFSET register to get an estimate of pending
1122  *      CRBs on the FIFO and compute the delay dynamically on each retry.
1123  *      But that is not really needed until we support NX-GZIP access from
1124  *      user space. (NX-842 driver waits for CSB and Fast thread-wakeup
1125  *      doesn't use credit checking).
1126  */
1127 static void poll_window_credits(struct vas_window *window)
1128 {
1129         u64 val;
1130         int creds, mode;
1131 
1132         val = read_hvwc_reg(window, VREG(WINCTL));
1133         if (window->tx_win)
1134                 mode = GET_FIELD(VAS_WINCTL_TX_WCRED_MODE, val);
1135         else
1136                 mode = GET_FIELD(VAS_WINCTL_RX_WCRED_MODE, val);
1137 
1138         if (!mode)
1139                 return;
1140 retry:
1141         if (window->tx_win) {
1142                 val = read_hvwc_reg(window, VREG(TX_WCRED));
1143                 creds = GET_FIELD(VAS_TX_WCRED, val);
1144         } else {
1145                 val = read_hvwc_reg(window, VREG(LRX_WCRED));
1146                 creds = GET_FIELD(VAS_LRX_WCRED, val);
1147         }
1148 
1149         if (creds < window->wcreds_max) {
1150                 val = 0;
1151                 set_current_state(TASK_UNINTERRUPTIBLE);
1152                 schedule_timeout(msecs_to_jiffies(10));
1153                 goto retry;
1154         }
1155 }
1156 
1157 /*
1158  * Wait for the window to go to "not-busy" state. It should only take a
1159  * short time to queue a CRB, so window should not be busy for too long.
1160  * Trying 5ms intervals.
1161  */
1162 static void poll_window_busy_state(struct vas_window *window)
1163 {
1164         int busy;
1165         u64 val;
1166 
1167 retry:
1168         val = read_hvwc_reg(window, VREG(WIN_STATUS));
1169         busy = GET_FIELD(VAS_WIN_BUSY, val);
1170         if (busy) {
1171                 val = 0;
1172                 set_current_state(TASK_UNINTERRUPTIBLE);
1173                 schedule_timeout(msecs_to_jiffies(5));
1174                 goto retry;
1175         }
1176 }
1177 
1178 /*
1179  * Have the hardware cast a window out of cache and wait for it to
1180  * be completed.
1181  *
1182  * NOTE: It can take a relatively long time to cast the window context
1183  *      out of the cache. It is not strictly necessary to cast out if:
1184  *
1185  *      - we clear the "Pin Window" bit (so hardware is free to evict)
1186  *
1187  *      - we re-initialize the window context when it is reassigned.
1188  *
1189  *      We do the former in vas_win_close() and latter in vas_win_open().
1190  *      So, ignoring the cast-out for now. We can add it as needed. If
1191  *      casting out becomes necessary we should consider offloading the
1192  *      job to a worker thread, so the window close can proceed quickly.
1193  */
1194 static void poll_window_castout(struct vas_window *window)
1195 {
1196         /* stub for now */
1197 }
1198 
1199 /*
1200  * Unpin and close a window so no new requests are accepted and the
1201  * hardware can evict this window from cache if necessary.
1202  */
1203 static void unpin_close_window(struct vas_window *window)
1204 {
1205         u64 val;
1206 
1207         val = read_hvwc_reg(window, VREG(WINCTL));
1208         val = SET_FIELD(VAS_WINCTL_PIN, val, 0);
1209         val = SET_FIELD(VAS_WINCTL_OPEN, val, 0);
1210         write_hvwc_reg(window, VREG(WINCTL), val);
1211 }
1212 
1213 /*
1214  * Close a window.
1215  *
1216  * See Section 1.12.1 of VAS workbook v1.05 for details on closing window:
1217  *      - Disable new paste operations (unmap paste address)
1218  *      - Poll for the "Window Busy" bit to be cleared
1219  *      - Clear the Open/Enable bit for the Window.
1220  *      - Poll for return of window Credits (implies FIFO empty for Rx win?)
1221  *      - Unpin and cast window context out of cache
1222  *
1223  * Besides the hardware, kernel has some bookkeeping of course.
1224  */
1225 int vas_win_close(struct vas_window *window)
1226 {
1227         if (!window)
1228                 return 0;
1229 
1230         if (!window->tx_win && atomic_read(&window->num_txwins) != 0) {
1231                 pr_devel("Attempting to close an active Rx window!\n");
1232                 WARN_ON_ONCE(1);
1233                 return -EBUSY;
1234         }
1235 
1236         unmap_paste_region(window);
1237 
1238         clear_vinst_win(window);
1239 
1240         poll_window_busy_state(window);
1241 
1242         unpin_close_window(window);
1243 
1244         poll_window_credits(window);
1245 
1246         poll_window_castout(window);
1247 
1248         /* if send window, drop reference to matching receive window */
1249         if (window->tx_win)
1250                 put_rx_win(window->rxwin);
1251 
1252         vas_window_free(window);
1253 
1254         return 0;
1255 }
1256 EXPORT_SYMBOL_GPL(vas_win_close);
/* [<][>][^][v][top][bottom][index][help] */
root/arch/powerpc/platforms/powernv/vas-window.c

DEFINITIONS
