1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * IOMMU API for Graphics Address Relocation Table on Tegra20 4 * 5 * Copyright (c) 2010-2012, NVIDIA CORPORATION. All rights reserved. 6 * 7 * Author: Hiroshi DOYU <hdoyu@nvidia.com> 8 */ 9 10 #define dev_fmt(fmt) "gart: " fmt 11 12 #include <linux/io.h> 13 #include <linux/iommu.h> 14 #include <linux/moduleparam.h> 15 #include <linux/platform_device.h> 16 #include <linux/slab.h> 17 #include <linux/spinlock.h> 18 #include <linux/vmalloc.h> 19 20 #include <soc/tegra/mc.h> 21 22 #define GART_REG_BASE 0x24 23 #define GART_CONFIG (0x24 - GART_REG_BASE) 24 #define GART_ENTRY_ADDR (0x28 - GART_REG_BASE) 25 #define GART_ENTRY_DATA (0x2c - GART_REG_BASE) 26 27 #define GART_ENTRY_PHYS_ADDR_VALID BIT(31) 28 29 #define GART_PAGE_SHIFT 12 30 #define GART_PAGE_SIZE (1 << GART_PAGE_SHIFT) 31 #define GART_PAGE_MASK GENMASK(30, GART_PAGE_SHIFT) 32 33 /* bitmap of the page sizes currently supported */ 34 #define GART_IOMMU_PGSIZES (GART_PAGE_SIZE) 35 36 struct gart_device { 37 void __iomem *regs; 38 u32 *savedata; 39 unsigned long iovmm_base; /* offset to vmm_area start */ 40 unsigned long iovmm_end; /* offset to vmm_area end */ 41 spinlock_t pte_lock; /* for pagetable */ 42 spinlock_t dom_lock; /* for active domain */ 43 unsigned int active_devices; /* number of active devices */ 44 struct iommu_domain *active_domain; /* current active domain */ 45 struct iommu_device iommu; /* IOMMU Core handle */ 46 struct device *dev; 47 }; 48 49 static struct gart_device *gart_handle; /* unique for a system */ 50 51 static bool gart_debug; 52 53 /* 54 * Any interaction between any block on PPSB and a block on APB or AHB 55 * must have these read-back to ensure the APB/AHB bus transaction is 56 * complete before initiating activity on the PPSB block. 57 */ 58 #define FLUSH_GART_REGS(gart) readl_relaxed((gart)->regs + GART_CONFIG) 59 60 #define for_each_gart_pte(gart, iova) \ 61 for (iova = gart->iovmm_base; \ 62 iova < gart->iovmm_end; \ 63 iova += GART_PAGE_SIZE) 64 65 static inline void gart_set_pte(struct gart_device *gart, 66 unsigned long iova, unsigned long pte) 67 { 68 writel_relaxed(iova, gart->regs + GART_ENTRY_ADDR); 69 writel_relaxed(pte, gart->regs + GART_ENTRY_DATA); 70 } 71 72 static inline unsigned long gart_read_pte(struct gart_device *gart, 73 unsigned long iova) 74 { 75 unsigned long pte; 76 77 writel_relaxed(iova, gart->regs + GART_ENTRY_ADDR); 78 pte = readl_relaxed(gart->regs + GART_ENTRY_DATA); 79 80 return pte; 81 } 82 83 static void do_gart_setup(struct gart_device *gart, const u32 *data) 84 { 85 unsigned long iova; 86 87 for_each_gart_pte(gart, iova) 88 gart_set_pte(gart, iova, data ? *(data++) : 0); 89 90 writel_relaxed(1, gart->regs + GART_CONFIG); 91 FLUSH_GART_REGS(gart); 92 } 93 94 static inline bool gart_iova_range_invalid(struct gart_device *gart, 95 unsigned long iova, size_t bytes) 96 { 97 return unlikely(iova < gart->iovmm_base || bytes != GART_PAGE_SIZE || 98 iova + bytes > gart->iovmm_end); 99 } 100 101 static inline bool gart_pte_valid(struct gart_device *gart, unsigned long iova) 102 { 103 return !!(gart_read_pte(gart, iova) & GART_ENTRY_PHYS_ADDR_VALID); 104 } 105 106 static int gart_iommu_attach_dev(struct iommu_domain *domain, 107 struct device *dev) 108 { 109 struct gart_device *gart = gart_handle; 110 int ret = 0; 111 112 spin_lock(&gart->dom_lock); 113 114 if (gart->active_domain && gart->active_domain != domain) { 115 ret = -EBUSY; 116 } else if (dev->archdata.iommu != domain) { 117 dev->archdata.iommu = domain; 118 gart->active_domain = domain; 119 gart->active_devices++; 120 } 121 122 spin_unlock(&gart->dom_lock); 123 124 return ret; 125 } 126 127 static void gart_iommu_detach_dev(struct iommu_domain *domain, 128 struct device *dev) 129 { 130 struct gart_device *gart = gart_handle; 131 132 spin_lock(&gart->dom_lock); 133 134 if (dev->archdata.iommu == domain) { 135 dev->archdata.iommu = NULL; 136 137 if (--gart->active_devices == 0) 138 gart->active_domain = NULL; 139 } 140 141 spin_unlock(&gart->dom_lock); 142 } 143 144 static struct iommu_domain *gart_iommu_domain_alloc(unsigned type) 145 { 146 struct iommu_domain *domain; 147 148 if (type != IOMMU_DOMAIN_UNMANAGED) 149 return NULL; 150 151 domain = kzalloc(sizeof(*domain), GFP_KERNEL); 152 if (domain) { 153 domain->geometry.aperture_start = gart_handle->iovmm_base; 154 domain->geometry.aperture_end = gart_handle->iovmm_end - 1; 155 domain->geometry.force_aperture = true; 156 } 157 158 return domain; 159 } 160 161 static void gart_iommu_domain_free(struct iommu_domain *domain) 162 { 163 WARN_ON(gart_handle->active_domain == domain); 164 kfree(domain); 165 } 166 167 static inline int __gart_iommu_map(struct gart_device *gart, unsigned long iova, 168 unsigned long pa) 169 { 170 if (unlikely(gart_debug && gart_pte_valid(gart, iova))) { 171 dev_err(gart->dev, "Page entry is in-use\n"); 172 return -EINVAL; 173 } 174 175 gart_set_pte(gart, iova, GART_ENTRY_PHYS_ADDR_VALID | pa); 176 177 return 0; 178 } 179 180 static int gart_iommu_map(struct iommu_domain *domain, unsigned long iova, 181 phys_addr_t pa, size_t bytes, int prot) 182 { 183 struct gart_device *gart = gart_handle; 184 int ret; 185 186 if (gart_iova_range_invalid(gart, iova, bytes)) 187 return -EINVAL; 188 189 spin_lock(&gart->pte_lock); 190 ret = __gart_iommu_map(gart, iova, (unsigned long)pa); 191 spin_unlock(&gart->pte_lock); 192 193 return ret; 194 } 195 196 static inline int __gart_iommu_unmap(struct gart_device *gart, 197 unsigned long iova) 198 { 199 if (unlikely(gart_debug && !gart_pte_valid(gart, iova))) { 200 dev_err(gart->dev, "Page entry is invalid\n"); 201 return -EINVAL; 202 } 203 204 gart_set_pte(gart, iova, 0); 205 206 return 0; 207 } 208 209 static size_t gart_iommu_unmap(struct iommu_domain *domain, unsigned long iova, 210 size_t bytes, struct iommu_iotlb_gather *gather) 211 { 212 struct gart_device *gart = gart_handle; 213 int err; 214 215 if (gart_iova_range_invalid(gart, iova, bytes)) 216 return 0; 217 218 spin_lock(&gart->pte_lock); 219 err = __gart_iommu_unmap(gart, iova); 220 spin_unlock(&gart->pte_lock); 221 222 return err ? 0 : bytes; 223 } 224 225 static phys_addr_t gart_iommu_iova_to_phys(struct iommu_domain *domain, 226 dma_addr_t iova) 227 { 228 struct gart_device *gart = gart_handle; 229 unsigned long pte; 230 231 if (gart_iova_range_invalid(gart, iova, GART_PAGE_SIZE)) 232 return -EINVAL; 233 234 spin_lock(&gart->pte_lock); 235 pte = gart_read_pte(gart, iova); 236 spin_unlock(&gart->pte_lock); 237 238 return pte & GART_PAGE_MASK; 239 } 240 241 static bool gart_iommu_capable(enum iommu_cap cap) 242 { 243 return false; 244 } 245 246 static int gart_iommu_add_device(struct device *dev) 247 { 248 struct iommu_group *group; 249 250 if (!dev->iommu_fwspec) 251 return -ENODEV; 252 253 group = iommu_group_get_for_dev(dev); 254 if (IS_ERR(group)) 255 return PTR_ERR(group); 256 257 iommu_group_put(group); 258 259 iommu_device_link(&gart_handle->iommu, dev); 260 261 return 0; 262 } 263 264 static void gart_iommu_remove_device(struct device *dev) 265 { 266 iommu_group_remove_device(dev); 267 iommu_device_unlink(&gart_handle->iommu, dev); 268 } 269 270 static int gart_iommu_of_xlate(struct device *dev, 271 struct of_phandle_args *args) 272 { 273 return 0; 274 } 275 276 static void gart_iommu_sync_map(struct iommu_domain *domain) 277 { 278 FLUSH_GART_REGS(gart_handle); 279 } 280 281 static void gart_iommu_sync(struct iommu_domain *domain, 282 struct iommu_iotlb_gather *gather) 283 { 284 gart_iommu_sync_map(domain); 285 } 286 287 static const struct iommu_ops gart_iommu_ops = { 288 .capable = gart_iommu_capable, 289 .domain_alloc = gart_iommu_domain_alloc, 290 .domain_free = gart_iommu_domain_free, 291 .attach_dev = gart_iommu_attach_dev, 292 .detach_dev = gart_iommu_detach_dev, 293 .add_device = gart_iommu_add_device, 294 .remove_device = gart_iommu_remove_device, 295 .device_group = generic_device_group, 296 .map = gart_iommu_map, 297 .unmap = gart_iommu_unmap, 298 .iova_to_phys = gart_iommu_iova_to_phys, 299 .pgsize_bitmap = GART_IOMMU_PGSIZES, 300 .of_xlate = gart_iommu_of_xlate, 301 .iotlb_sync_map = gart_iommu_sync_map, 302 .iotlb_sync = gart_iommu_sync, 303 }; 304 305 int tegra_gart_suspend(struct gart_device *gart) 306 { 307 u32 *data = gart->savedata; 308 unsigned long iova; 309 310 /* 311 * All GART users shall be suspended at this point. Disable 312 * address translation to trap all GART accesses as invalid 313 * memory accesses. 314 */ 315 writel_relaxed(0, gart->regs + GART_CONFIG); 316 FLUSH_GART_REGS(gart); 317 318 for_each_gart_pte(gart, iova) 319 *(data++) = gart_read_pte(gart, iova); 320 321 return 0; 322 } 323 324 int tegra_gart_resume(struct gart_device *gart) 325 { 326 do_gart_setup(gart, gart->savedata); 327 328 return 0; 329 } 330 331 struct gart_device *tegra_gart_probe(struct device *dev, struct tegra_mc *mc) 332 { 333 struct gart_device *gart; 334 struct resource *res; 335 int err; 336 337 BUILD_BUG_ON(PAGE_SHIFT != GART_PAGE_SHIFT); 338 339 /* the GART memory aperture is required */ 340 res = platform_get_resource(to_platform_device(dev), IORESOURCE_MEM, 1); 341 if (!res) { 342 dev_err(dev, "Memory aperture resource unavailable\n"); 343 return ERR_PTR(-ENXIO); 344 } 345 346 gart = kzalloc(sizeof(*gart), GFP_KERNEL); 347 if (!gart) 348 return ERR_PTR(-ENOMEM); 349 350 gart_handle = gart; 351 352 gart->dev = dev; 353 gart->regs = mc->regs + GART_REG_BASE; 354 gart->iovmm_base = res->start; 355 gart->iovmm_end = res->end + 1; 356 spin_lock_init(&gart->pte_lock); 357 spin_lock_init(&gart->dom_lock); 358 359 do_gart_setup(gart, NULL); 360 361 err = iommu_device_sysfs_add(&gart->iommu, dev, NULL, "gart"); 362 if (err) 363 goto free_gart; 364 365 iommu_device_set_ops(&gart->iommu, &gart_iommu_ops); 366 iommu_device_set_fwnode(&gart->iommu, dev->fwnode); 367 368 err = iommu_device_register(&gart->iommu); 369 if (err) 370 goto remove_sysfs; 371 372 gart->savedata = vmalloc(resource_size(res) / GART_PAGE_SIZE * 373 sizeof(u32)); 374 if (!gart->savedata) { 375 err = -ENOMEM; 376 goto unregister_iommu; 377 } 378 379 return gart; 380 381 unregister_iommu: 382 iommu_device_unregister(&gart->iommu); 383 remove_sysfs: 384 iommu_device_sysfs_remove(&gart->iommu); 385 free_gart: 386 kfree(gart); 387 388 return ERR_PTR(err); 389 } 390 391 module_param(gart_debug, bool, 0644); 392 MODULE_PARM_DESC(gart_debug, "Enable GART debugging"); 393