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1// SPDX-License-Identifier: GPL-2.0-only OR MIT2/*3 * Apple SART device driver4 * Copyright (C) The Asahi Linux Contributors5 *6 * Apple SART is a simple address filter for some DMA transactions.7 * Regions of physical memory must be added to the SART's allow8 * list before any DMA can target these. Unlike a proper9 * IOMMU no remapping can be done and special support in the10 * consumer driver is required since not all DMA transactions of11 * a single device are subject to SART filtering.12 */13 14#include <linux/soc/apple/sart.h>15#include <linux/atomic.h>16#include <linux/bits.h>17#include <linux/bitfield.h>18#include <linux/device.h>19#include <linux/io.h>20#include <linux/module.h>21#include <linux/of.h>22#include <linux/of_platform.h>23#include <linux/platform_device.h>24#include <linux/types.h>25 26#define APPLE_SART_MAX_ENTRIES 1627 28/* This is probably a bitfield but the exact meaning of each bit is unknown. */29#define APPLE_SART_FLAGS_ALLOW 0xff30 31/* SARTv2 registers */32#define APPLE_SART2_CONFIG(idx) (0x00 + 4 * (idx))33#define APPLE_SART2_CONFIG_FLAGS GENMASK(31, 24)34#define APPLE_SART2_CONFIG_SIZE GENMASK(23, 0)35#define APPLE_SART2_CONFIG_SIZE_SHIFT 1236#define APPLE_SART2_CONFIG_SIZE_MAX GENMASK(23, 0)37 38#define APPLE_SART2_PADDR(idx) (0x40 + 4 * (idx))39#define APPLE_SART2_PADDR_SHIFT 1240 41/* SARTv3 registers */42#define APPLE_SART3_CONFIG(idx) (0x00 + 4 * (idx))43 44#define APPLE_SART3_PADDR(idx) (0x40 + 4 * (idx))45#define APPLE_SART3_PADDR_SHIFT 1246 47#define APPLE_SART3_SIZE(idx) (0x80 + 4 * (idx))48#define APPLE_SART3_SIZE_SHIFT 1249#define APPLE_SART3_SIZE_MAX GENMASK(29, 0)50 51struct apple_sart_ops {52 void (*get_entry)(struct apple_sart *sart, int index, u8 *flags,53 phys_addr_t *paddr, size_t *size);54 void (*set_entry)(struct apple_sart *sart, int index, u8 flags,55 phys_addr_t paddr_shifted, size_t size_shifted);56 unsigned int size_shift;57 unsigned int paddr_shift;58 size_t size_max;59};60 61struct apple_sart {62 struct device *dev;63 void __iomem *regs;64 65 const struct apple_sart_ops *ops;66 67 unsigned long protected_entries;68 unsigned long used_entries;69};70 71static void sart2_get_entry(struct apple_sart *sart, int index, u8 *flags,72 phys_addr_t *paddr, size_t *size)73{74 u32 cfg = readl(sart->regs + APPLE_SART2_CONFIG(index));75 phys_addr_t paddr_ = readl(sart->regs + APPLE_SART2_PADDR(index));76 size_t size_ = FIELD_GET(APPLE_SART2_CONFIG_SIZE, cfg);77 78 *flags = FIELD_GET(APPLE_SART2_CONFIG_FLAGS, cfg);79 *size = size_ << APPLE_SART2_CONFIG_SIZE_SHIFT;80 *paddr = paddr_ << APPLE_SART2_PADDR_SHIFT;81}82 83static void sart2_set_entry(struct apple_sart *sart, int index, u8 flags,84 phys_addr_t paddr_shifted, size_t size_shifted)85{86 u32 cfg;87 88 cfg = FIELD_PREP(APPLE_SART2_CONFIG_FLAGS, flags);89 cfg |= FIELD_PREP(APPLE_SART2_CONFIG_SIZE, size_shifted);90 91 writel(paddr_shifted, sart->regs + APPLE_SART2_PADDR(index));92 writel(cfg, sart->regs + APPLE_SART2_CONFIG(index));93}94 95static struct apple_sart_ops sart_ops_v2 = {96 .get_entry = sart2_get_entry,97 .set_entry = sart2_set_entry,98 .size_shift = APPLE_SART2_CONFIG_SIZE_SHIFT,99 .paddr_shift = APPLE_SART2_PADDR_SHIFT,100 .size_max = APPLE_SART2_CONFIG_SIZE_MAX,101};102 103static void sart3_get_entry(struct apple_sart *sart, int index, u8 *flags,104 phys_addr_t *paddr, size_t *size)105{106 phys_addr_t paddr_ = readl(sart->regs + APPLE_SART3_PADDR(index));107 size_t size_ = readl(sart->regs + APPLE_SART3_SIZE(index));108 109 *flags = readl(sart->regs + APPLE_SART3_CONFIG(index));110 *size = size_ << APPLE_SART3_SIZE_SHIFT;111 *paddr = paddr_ << APPLE_SART3_PADDR_SHIFT;112}113 114static void sart3_set_entry(struct apple_sart *sart, int index, u8 flags,115 phys_addr_t paddr_shifted, size_t size_shifted)116{117 writel(paddr_shifted, sart->regs + APPLE_SART3_PADDR(index));118 writel(size_shifted, sart->regs + APPLE_SART3_SIZE(index));119 writel(flags, sart->regs + APPLE_SART3_CONFIG(index));120}121 122static struct apple_sart_ops sart_ops_v3 = {123 .get_entry = sart3_get_entry,124 .set_entry = sart3_set_entry,125 .size_shift = APPLE_SART3_SIZE_SHIFT,126 .paddr_shift = APPLE_SART3_PADDR_SHIFT,127 .size_max = APPLE_SART3_SIZE_MAX,128};129 130static int apple_sart_probe(struct platform_device *pdev)131{132 int i;133 struct apple_sart *sart;134 struct device *dev = &pdev->dev;135 136 sart = devm_kzalloc(dev, sizeof(*sart), GFP_KERNEL);137 if (!sart)138 return -ENOMEM;139 140 sart->dev = dev;141 sart->ops = of_device_get_match_data(dev);142 143 sart->regs = devm_platform_ioremap_resource(pdev, 0);144 if (IS_ERR(sart->regs))145 return PTR_ERR(sart->regs);146 147 for (i = 0; i < APPLE_SART_MAX_ENTRIES; ++i) {148 u8 flags;149 size_t size;150 phys_addr_t paddr;151 152 sart->ops->get_entry(sart, i, &flags, &paddr, &size);153 154 if (!flags)155 continue;156 157 dev_dbg(sart->dev,158 "SART bootloader entry: index %02d; flags: 0x%02x; paddr: %pa; size: 0x%zx\n",159 i, flags, &paddr, size);160 set_bit(i, &sart->protected_entries);161 }162 163 platform_set_drvdata(pdev, sart);164 return 0;165}166 167static void apple_sart_put_device(void *dev)168{169 put_device(dev);170}171 172struct apple_sart *devm_apple_sart_get(struct device *dev)173{174 struct device_node *sart_node;175 struct platform_device *sart_pdev;176 struct apple_sart *sart;177 int ret;178 179 sart_node = of_parse_phandle(dev->of_node, "apple,sart", 0);180 if (!sart_node)181 return ERR_PTR(-ENODEV);182 183 sart_pdev = of_find_device_by_node(sart_node);184 of_node_put(sart_node);185 186 if (!sart_pdev)187 return ERR_PTR(-ENODEV);188 189 sart = dev_get_drvdata(&sart_pdev->dev);190 if (!sart) {191 put_device(&sart_pdev->dev);192 return ERR_PTR(-EPROBE_DEFER);193 }194 195 ret = devm_add_action_or_reset(dev, apple_sart_put_device,196 &sart_pdev->dev);197 if (ret)198 return ERR_PTR(ret);199 200 device_link_add(dev, &sart_pdev->dev,201 DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_SUPPLIER);202 203 return sart;204}205EXPORT_SYMBOL_GPL(devm_apple_sart_get);206 207static int sart_set_entry(struct apple_sart *sart, int index, u8 flags,208 phys_addr_t paddr, size_t size)209{210 if (size & ((1 << sart->ops->size_shift) - 1))211 return -EINVAL;212 if (paddr & ((1 << sart->ops->paddr_shift) - 1))213 return -EINVAL;214 215 paddr >>= sart->ops->size_shift;216 size >>= sart->ops->paddr_shift;217 218 if (size > sart->ops->size_max)219 return -EINVAL;220 221 sart->ops->set_entry(sart, index, flags, paddr, size);222 return 0;223}224 225int apple_sart_add_allowed_region(struct apple_sart *sart, phys_addr_t paddr,226 size_t size)227{228 int i, ret;229 230 for (i = 0; i < APPLE_SART_MAX_ENTRIES; ++i) {231 if (test_bit(i, &sart->protected_entries))232 continue;233 if (test_and_set_bit(i, &sart->used_entries))234 continue;235 236 ret = sart_set_entry(sart, i, APPLE_SART_FLAGS_ALLOW, paddr,237 size);238 if (ret) {239 dev_dbg(sart->dev,240 "unable to set entry %d to [%pa, 0x%zx]\n",241 i, &paddr, size);242 clear_bit(i, &sart->used_entries);243 return ret;244 }245 246 dev_dbg(sart->dev, "wrote [%pa, 0x%zx] to %d\n", &paddr, size,247 i);248 return 0;249 }250 251 dev_warn(sart->dev,252 "no free entries left to add [paddr: 0x%pa, size: 0x%zx]\n",253 &paddr, size);254 255 return -EBUSY;256}257EXPORT_SYMBOL_GPL(apple_sart_add_allowed_region);258 259int apple_sart_remove_allowed_region(struct apple_sart *sart, phys_addr_t paddr,260 size_t size)261{262 int i;263 264 dev_dbg(sart->dev,265 "will remove [paddr: %pa, size: 0x%zx] from allowed regions\n",266 &paddr, size);267 268 for (i = 0; i < APPLE_SART_MAX_ENTRIES; ++i) {269 u8 eflags;270 size_t esize;271 phys_addr_t epaddr;272 273 if (test_bit(i, &sart->protected_entries))274 continue;275 276 sart->ops->get_entry(sart, i, &eflags, &epaddr, &esize);277 278 if (epaddr != paddr || esize != size)279 continue;280 281 sart->ops->set_entry(sart, i, 0, 0, 0);282 283 clear_bit(i, &sart->used_entries);284 dev_dbg(sart->dev, "cleared entry %d\n", i);285 return 0;286 }287 288 dev_warn(sart->dev, "entry [paddr: 0x%pa, size: 0x%zx] not found\n",289 &paddr, size);290 291 return -EINVAL;292}293EXPORT_SYMBOL_GPL(apple_sart_remove_allowed_region);294 295static void apple_sart_shutdown(struct platform_device *pdev)296{297 struct apple_sart *sart = dev_get_drvdata(&pdev->dev);298 int i;299 300 for (i = 0; i < APPLE_SART_MAX_ENTRIES; ++i) {301 if (test_bit(i, &sart->protected_entries))302 continue;303 304 sart->ops->set_entry(sart, i, 0, 0, 0);305 }306}307 308static const struct of_device_id apple_sart_of_match[] = {309 {310 .compatible = "apple,t6000-sart",311 .data = &sart_ops_v3,312 },313 {314 .compatible = "apple,t8103-sart",315 .data = &sart_ops_v2,316 },317 {}318};319MODULE_DEVICE_TABLE(of, apple_sart_of_match);320 321static struct platform_driver apple_sart_driver = {322 .driver = {323 .name = "apple-sart",324 .of_match_table = apple_sart_of_match,325 },326 .probe = apple_sart_probe,327 .shutdown = apple_sart_shutdown,328};329module_platform_driver(apple_sart_driver);330 331MODULE_LICENSE("Dual MIT/GPL");332MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");333MODULE_DESCRIPTION("Apple SART driver");334