arch/sparc/mm/iommu.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * iommu.c:  IOMMU specific routines for memory management.
   4  *
   5  * Copyright (C) 1995 David S. Miller  (davem@caip.rutgers.edu)
   6  * Copyright (C) 1995,2002 Pete Zaitcev     (zaitcev@yahoo.com)
   7  * Copyright (C) 1996 Eddie C. Dost    (ecd@skynet.be)
   8  * Copyright (C) 1997,1998 Jakub Jelinek    (jj@sunsite.mff.cuni.cz)
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/mm.h>
  14 #include <linux/slab.h>
  15 #include <linux/highmem.h>      /* pte_offset_map => kmap_atomic */
  16 #include <linux/dma-mapping.h>
  17 #include <linux/of.h>
  18 #include <linux/of_device.h>
  19
  20 #include <asm/pgalloc.h>
  21 #include <asm/pgtable.h>
  22 #include <asm/io.h>
  23 #include <asm/mxcc.h>
  24 #include <asm/mbus.h>
  25 #include <asm/cacheflush.h>
  26 #include <asm/tlbflush.h>
  27 #include <asm/bitext.h>
  28 #include <asm/iommu.h>
  29 #include <asm/dma.h>
  30
  31 #include "mm_32.h"
  32
  33 /*
  34  * This can be sized dynamically, but we will do this
  35  * only when we have a guidance about actual I/O pressures.
  36  */
  37 #define IOMMU_RNGE      IOMMU_RNGE_256MB
  38 #define IOMMU_START     0xF0000000
  39 #define IOMMU_WINSIZE   (256*1024*1024U)
  40 #define IOMMU_NPTES     (IOMMU_WINSIZE/PAGE_SIZE)       /* 64K PTEs, 256KB */
  41 #define IOMMU_ORDER     6                               /* 4096 * (1<<6) */
  42
  43 static int viking_flush;
  44 /* viking.S */
  45 extern void viking_flush_page(unsigned long page);
  46 extern void viking_mxcc_flush_page(unsigned long page);
  47
  48 /*
  49  * Values precomputed according to CPU type.
  50  */
  51 static unsigned int ioperm_noc;         /* Consistent mapping iopte flags */
  52 static pgprot_t dvma_prot;              /* Consistent mapping pte flags */
  53
  54 #define IOPERM        (IOPTE_CACHE | IOPTE_WRITE | IOPTE_VALID)
  55 #define MKIOPTE(pfn, perm) (((((pfn)<<8) & IOPTE_PAGE) | (perm)) & ~IOPTE_WAZ)
  56
  57 static void __init sbus_iommu_init(struct platform_device *op)
  58 {
  59         struct iommu_struct *iommu;
  60         unsigned int impl, vers;
  61         unsigned long *bitmap;
  62         unsigned long control;
  63         unsigned long base;
  64         unsigned long tmp;
  65
  66         iommu = kmalloc(sizeof(struct iommu_struct), GFP_KERNEL);
  67         if (!iommu) {
  68                 prom_printf("Unable to allocate iommu structure\n");
  69                 prom_halt();
  70         }
  71
  72         iommu->regs = of_ioremap(&op->resource[0], 0, PAGE_SIZE * 3,
  73                                  "iommu_regs");
  74         if (!iommu->regs) {
  75                 prom_printf("Cannot map IOMMU registers\n");
  76                 prom_halt();
  77         }
  78
  79         control = sbus_readl(&iommu->regs->control);
  80         impl = (control & IOMMU_CTRL_IMPL) >> 28;
  81         vers = (control & IOMMU_CTRL_VERS) >> 24;
  82         control &= ~(IOMMU_CTRL_RNGE);
  83         control |= (IOMMU_RNGE_256MB | IOMMU_CTRL_ENAB);
  84         sbus_writel(control, &iommu->regs->control);
  85
  86         iommu_invalidate(iommu->regs);
  87         iommu->start = IOMMU_START;
  88         iommu->end = 0xffffffff;
  89
  90         /* Allocate IOMMU page table */
  91         /* Stupid alignment constraints give me a headache.
  92            We need 256K or 512K or 1M or 2M area aligned to
  93            its size and current gfp will fortunately give
  94            it to us. */
  95         tmp = __get_free_pages(GFP_KERNEL, IOMMU_ORDER);
  96         if (!tmp) {
  97                 prom_printf("Unable to allocate iommu table [0x%lx]\n",
  98                             IOMMU_NPTES * sizeof(iopte_t));
  99                 prom_halt();
 100         }
 101         iommu->page_table = (iopte_t *)tmp;
 102
 103         /* Initialize new table. */
 104         memset(iommu->page_table, 0, IOMMU_NPTES*sizeof(iopte_t));
 105         flush_cache_all();
 106         flush_tlb_all();
 107
 108         base = __pa((unsigned long)iommu->page_table) >> 4;
 109         sbus_writel(base, &iommu->regs->base);
 110         iommu_invalidate(iommu->regs);
 111
 112         bitmap = kmalloc(IOMMU_NPTES>>3, GFP_KERNEL);
 113         if (!bitmap) {
 114                 prom_printf("Unable to allocate iommu bitmap [%d]\n",
 115                             (int)(IOMMU_NPTES>>3));
 116                 prom_halt();
 117         }
 118         bit_map_init(&iommu->usemap, bitmap, IOMMU_NPTES);
 119         /* To be coherent on HyperSparc, the page color of DVMA
 120          * and physical addresses must match.
 121          */
 122         if (srmmu_modtype == HyperSparc)
 123                 iommu->usemap.num_colors = vac_cache_size >> PAGE_SHIFT;
 124         else
 125                 iommu->usemap.num_colors = 1;
 126
 127         printk(KERN_INFO "IOMMU: impl %d vers %d table 0x%p[%d B] map [%d b]\n",
 128                impl, vers, iommu->page_table,
 129                (int)(IOMMU_NPTES*sizeof(iopte_t)), (int)IOMMU_NPTES);
 130
 131         op->dev.archdata.iommu = iommu;
 132 }
 133
 134 static int __init iommu_init(void)
 135 {
 136         struct device_node *dp;
 137
 138         for_each_node_by_name(dp, "iommu") {
 139                 struct platform_device *op = of_find_device_by_node(dp);
 140
 141                 sbus_iommu_init(op);
 142                 of_propagate_archdata(op);
 143         }
 144
 145         return 0;
 146 }
 147
 148 subsys_initcall(iommu_init);
 149
 150 /* Flush the iotlb entries to ram. */
 151 /* This could be better if we didn't have to flush whole pages. */
 152 static void iommu_flush_iotlb(iopte_t *iopte, unsigned int niopte)
 153 {
 154         unsigned long start;
 155         unsigned long end;
 156
 157         start = (unsigned long)iopte;
 158         end = PAGE_ALIGN(start + niopte*sizeof(iopte_t));
 159         start &= PAGE_MASK;
 160         if (viking_mxcc_present) {
 161                 while(start < end) {
 162                         viking_mxcc_flush_page(start);
 163                         start += PAGE_SIZE;
 164                 }
 165         } else if (viking_flush) {
 166                 while(start < end) {
 167                         viking_flush_page(start);
 168                         start += PAGE_SIZE;
 169                 }
 170         } else {
 171                 while(start < end) {
 172                         __flush_page_to_ram(start);
 173                         start += PAGE_SIZE;
 174                 }
 175         }
 176 }
 177
 178 static dma_addr_t __sbus_iommu_map_page(struct device *dev, struct page *page,
 179                 unsigned long offset, size_t len, bool per_page_flush)
 180 {
 181         struct iommu_struct *iommu = dev->archdata.iommu;
 182         phys_addr_t paddr = page_to_phys(page) + offset;
 183         unsigned long off = paddr & ~PAGE_MASK;
 184         unsigned long npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 185         unsigned long pfn = __phys_to_pfn(paddr);
 186         unsigned int busa, busa0;
 187         iopte_t *iopte, *iopte0;
 188         int ioptex, i;
 189
 190         /* XXX So what is maxphys for us and how do drivers know it? */
 191         if (!len || len > 256 * 1024)
 192                 return DMA_MAPPING_ERROR;
 193
 194         /*
 195          * We expect unmapped highmem pages to be not in the cache.
 196          * XXX Is this a good assumption?
 197          * XXX What if someone else unmaps it here and races us?
 198          */
 199         if (per_page_flush && !PageHighMem(page)) {
 200                 unsigned long vaddr, p;
 201
 202                 vaddr = (unsigned long)page_address(page) + offset;
 203                 for (p = vaddr & PAGE_MASK; p < vaddr + len; p += PAGE_SIZE)
 204                         flush_page_for_dma(p);
 205         }
 206
 207         /* page color = pfn of page */
 208         ioptex = bit_map_string_get(&iommu->usemap, npages, pfn);
 209         if (ioptex < 0)
 210                 panic("iommu out");
 211         busa0 = iommu->start + (ioptex << PAGE_SHIFT);
 212         iopte0 = &iommu->page_table[ioptex];
 213
 214         busa = busa0;
 215         iopte = iopte0;
 216         for (i = 0; i < npages; i++) {
 217                 iopte_val(*iopte) = MKIOPTE(pfn, IOPERM);
 218                 iommu_invalidate_page(iommu->regs, busa);
 219                 busa += PAGE_SIZE;
 220                 iopte++;
 221                 pfn++;
 222         }
 223
 224         iommu_flush_iotlb(iopte0, npages);
 225         return busa0 + off;
 226 }
 227
 228 static dma_addr_t sbus_iommu_map_page_gflush(struct device *dev,
 229                 struct page *page, unsigned long offset, size_t len,
 230                 enum dma_data_direction dir, unsigned long attrs)
 231 {
 232         flush_page_for_dma(0);
 233         return __sbus_iommu_map_page(dev, page, offset, len, false);
 234 }
 235
 236 static dma_addr_t sbus_iommu_map_page_pflush(struct device *dev,
 237                 struct page *page, unsigned long offset, size_t len,
 238                 enum dma_data_direction dir, unsigned long attrs)
 239 {
 240         return __sbus_iommu_map_page(dev, page, offset, len, true);
 241 }
 242
 243 static int __sbus_iommu_map_sg(struct device *dev, struct scatterlist *sgl,
 244                 int nents, enum dma_data_direction dir, unsigned long attrs,
 245                 bool per_page_flush)
 246 {
 247         struct scatterlist *sg;
 248         int j;
 249
 250         for_each_sg(sgl, sg, nents, j) {
 251                 sg->dma_address =__sbus_iommu_map_page(dev, sg_page(sg),
 252                                 sg->offset, sg->length, per_page_flush);
 253                 if (sg->dma_address == DMA_MAPPING_ERROR)
 254                         return 0;
 255                 sg->dma_length = sg->length;
 256         }
 257
 258         return nents;
 259 }
 260
 261 static int sbus_iommu_map_sg_gflush(struct device *dev, struct scatterlist *sgl,
 262                 int nents, enum dma_data_direction dir, unsigned long attrs)
 263 {
 264         flush_page_for_dma(0);
 265         return __sbus_iommu_map_sg(dev, sgl, nents, dir, attrs, false);
 266 }
 267
 268 static int sbus_iommu_map_sg_pflush(struct device *dev, struct scatterlist *sgl,
 269                 int nents, enum dma_data_direction dir, unsigned long attrs)
 270 {
 271         return __sbus_iommu_map_sg(dev, sgl, nents, dir, attrs, true);
 272 }
 273
 274 static void sbus_iommu_unmap_page(struct device *dev, dma_addr_t dma_addr,
 275                 size_t len, enum dma_data_direction dir, unsigned long attrs)
 276 {
 277         struct iommu_struct *iommu = dev->archdata.iommu;
 278         unsigned int busa = dma_addr & PAGE_MASK;
 279         unsigned long off = dma_addr & ~PAGE_MASK;
 280         unsigned int npages = (off + len + PAGE_SIZE-1) >> PAGE_SHIFT;
 281         unsigned int ioptex = (busa - iommu->start) >> PAGE_SHIFT;
 282         unsigned int i;
 283
 284         BUG_ON(busa < iommu->start);
 285         for (i = 0; i < npages; i++) {
 286                 iopte_val(iommu->page_table[ioptex + i]) = 0;
 287                 iommu_invalidate_page(iommu->regs, busa);
 288                 busa += PAGE_SIZE;
 289         }
 290         bit_map_clear(&iommu->usemap, ioptex, npages);
 291 }
 292
 293 static void sbus_iommu_unmap_sg(struct device *dev, struct scatterlist *sgl,
 294                 int nents, enum dma_data_direction dir, unsigned long attrs)
 295 {
 296         struct scatterlist *sg;
 297         int i;
 298
 299         for_each_sg(sgl, sg, nents, i) {
 300                 sbus_iommu_unmap_page(dev, sg->dma_address, sg->length, dir,
 301                                 attrs);
 302                 sg->dma_address = 0x21212121;
 303         }
 304 }
 305
 306 #ifdef CONFIG_SBUS
 307 static void *sbus_iommu_alloc(struct device *dev, size_t len,
 308                 dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
 309 {
 310         struct iommu_struct *iommu = dev->archdata.iommu;
 311         unsigned long va, addr, page, end, ret;
 312         iopte_t *iopte = iommu->page_table;
 313         iopte_t *first;
 314         int ioptex;
 315
 316         /* XXX So what is maxphys for us and how do drivers know it? */
 317         if (!len || len > 256 * 1024)
 318                 return NULL;
 319
 320         len = PAGE_ALIGN(len);
 321         va = __get_free_pages(gfp | __GFP_ZERO, get_order(len));
 322         if (va == 0)
 323                 return NULL;
 324
 325         addr = ret = sparc_dma_alloc_resource(dev, len);
 326         if (!addr)
 327                 goto out_free_pages;
 328
 329         BUG_ON((va & ~PAGE_MASK) != 0);
 330         BUG_ON((addr & ~PAGE_MASK) != 0);
 331         BUG_ON((len & ~PAGE_MASK) != 0);
 332
 333         /* page color = physical address */
 334         ioptex = bit_map_string_get(&iommu->usemap, len >> PAGE_SHIFT,
 335                 addr >> PAGE_SHIFT);
 336         if (ioptex < 0)
 337                 panic("iommu out");
 338
 339         iopte += ioptex;
 340         first = iopte;
 341         end = addr + len;
 342         while(addr < end) {
 343                 page = va;
 344                 {
 345                         pgd_t *pgdp;
 346                         p4d_t *p4dp;
 347                         pud_t *pudp;
 348                         pmd_t *pmdp;
 349                         pte_t *ptep;
 350
 351                         if (viking_mxcc_present)
 352                                 viking_mxcc_flush_page(page);
 353                         else if (viking_flush)
 354                                 viking_flush_page(page);
 355                         else
 356                                 __flush_page_to_ram(page);
 357
 358                         pgdp = pgd_offset(&init_mm, addr);
 359                         p4dp = p4d_offset(pgdp, addr);
 360                         pudp = pud_offset(p4dp, addr);
 361                         pmdp = pmd_offset(pudp, addr);
 362                         ptep = pte_offset_map(pmdp, addr);
 363
 364                         set_pte(ptep, mk_pte(virt_to_page(page), dvma_prot));
 365                 }
 366                 iopte_val(*iopte++) =
 367                     MKIOPTE(page_to_pfn(virt_to_page(page)), ioperm_noc);
 368                 addr += PAGE_SIZE;
 369                 va += PAGE_SIZE;
 370         }
 371         /* P3: why do we need this?
 372          *
 373          * DAVEM: Because there are several aspects, none of which
 374          *        are handled by a single interface.  Some cpus are
 375          *        completely not I/O DMA coherent, and some have
 376          *        virtually indexed caches.  The driver DMA flushing
 377          *        methods handle the former case, but here during
 378          *        IOMMU page table modifications, and usage of non-cacheable
 379          *        cpu mappings of pages potentially in the cpu caches, we have
 380          *        to handle the latter case as well.
 381          */
 382         flush_cache_all();
 383         iommu_flush_iotlb(first, len >> PAGE_SHIFT);
 384         flush_tlb_all();
 385         iommu_invalidate(iommu->regs);
 386
 387         *dma_handle = iommu->start + (ioptex << PAGE_SHIFT);
 388         return (void *)ret;
 389
 390 out_free_pages:
 391         free_pages(va, get_order(len));
 392         return NULL;
 393 }
 394
 395 static void sbus_iommu_free(struct device *dev, size_t len, void *cpu_addr,
 396                                dma_addr_t busa, unsigned long attrs)
 397 {
 398         struct iommu_struct *iommu = dev->archdata.iommu;
 399         iopte_t *iopte = iommu->page_table;
 400         struct page *page = virt_to_page(cpu_addr);
 401         int ioptex = (busa - iommu->start) >> PAGE_SHIFT;
 402         unsigned long end;
 403
 404         if (!sparc_dma_free_resource(cpu_addr, len))
 405                 return;
 406
 407         BUG_ON((busa & ~PAGE_MASK) != 0);
 408         BUG_ON((len & ~PAGE_MASK) != 0);
 409
 410         iopte += ioptex;
 411         end = busa + len;
 412         while (busa < end) {
 413                 iopte_val(*iopte++) = 0;
 414                 busa += PAGE_SIZE;
 415         }
 416         flush_tlb_all();
 417         iommu_invalidate(iommu->regs);
 418         bit_map_clear(&iommu->usemap, ioptex, len >> PAGE_SHIFT);
 419
 420         __free_pages(page, get_order(len));
 421 }
 422 #endif
 423
 424 static const struct dma_map_ops sbus_iommu_dma_gflush_ops = {
 425 #ifdef CONFIG_SBUS
 426         .alloc                  = sbus_iommu_alloc,
 427         .free                   = sbus_iommu_free,
 428 #endif
 429         .map_page               = sbus_iommu_map_page_gflush,
 430         .unmap_page             = sbus_iommu_unmap_page,
 431         .map_sg                 = sbus_iommu_map_sg_gflush,
 432         .unmap_sg               = sbus_iommu_unmap_sg,
 433 };
 434
 435 static const struct dma_map_ops sbus_iommu_dma_pflush_ops = {
 436 #ifdef CONFIG_SBUS
 437         .alloc                  = sbus_iommu_alloc,
 438         .free                   = sbus_iommu_free,
 439 #endif
 440         .map_page               = sbus_iommu_map_page_pflush,
 441         .unmap_page             = sbus_iommu_unmap_page,
 442         .map_sg                 = sbus_iommu_map_sg_pflush,
 443         .unmap_sg               = sbus_iommu_unmap_sg,
 444 };
 445
 446 void __init ld_mmu_iommu(void)
 447 {
 448         if (flush_page_for_dma_global) {
 449                 /* flush_page_for_dma flushes everything, no matter of what page is it */
 450                 dma_ops = &sbus_iommu_dma_gflush_ops;
 451         } else {
 452                 dma_ops = &sbus_iommu_dma_pflush_ops;
 453         }
 454
 455         if (viking_mxcc_present || srmmu_modtype == HyperSparc) {
 456                 dvma_prot = __pgprot(SRMMU_CACHE | SRMMU_ET_PTE | SRMMU_PRIV);
 457                 ioperm_noc = IOPTE_CACHE | IOPTE_WRITE | IOPTE_VALID;
 458         } else {
 459                 dvma_prot = __pgprot(SRMMU_ET_PTE | SRMMU_PRIV);
 460                 ioperm_noc = IOPTE_WRITE | IOPTE_VALID;
 461         }
 462 }