drivers/soc/aspeed/aspeed-lpc-ctrl.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright 2017 IBM Corporation
   4  */
   5
   6 #include <linux/clk.h>
   7 #include <linux/log2.h>
   8 #include <linux/mfd/syscon.h>
   9 #include <linux/miscdevice.h>
  10 #include <linux/mm.h>
  11 #include <linux/module.h>
  12 #include <linux/of_address.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/poll.h>
  15 #include <linux/regmap.h>
  16
  17 #include <linux/aspeed-lpc-ctrl.h>
  18
  19 #define DEVICE_NAME     "aspeed-lpc-ctrl"
  20
  21 #define HICR5 0x80
  22 #define HICR5_ENL2H     BIT(8)
  23 #define HICR5_ENFWH     BIT(10)
  24
  25 #define HICR6 0x84
  26 #define SW_FWH2AHB      BIT(17)
  27
  28 #define HICR7 0x88
  29 #define HICR8 0x8c
  30
  31 struct aspeed_lpc_ctrl {
  32         struct miscdevice       miscdev;
  33         struct regmap           *regmap;
  34         struct clk              *clk;
  35         phys_addr_t             mem_base;
  36         resource_size_t         mem_size;
  37         u32                     pnor_size;
  38         u32                     pnor_base;
  39         bool                    fwh2ahb;
  40         struct regmap           *scu;
  41 };
  42
  43 static struct aspeed_lpc_ctrl *file_aspeed_lpc_ctrl(struct file *file)
  44 {
  45         return container_of(file->private_data, struct aspeed_lpc_ctrl,
  46                         miscdev);
  47 }
  48
  49 static int aspeed_lpc_ctrl_mmap(struct file *file, struct vm_area_struct *vma)
  50 {
  51         struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
  52         unsigned long vsize = vma->vm_end - vma->vm_start;
  53         pgprot_t prot = vma->vm_page_prot;
  54
  55         if (vma->vm_pgoff + vma_pages(vma) > lpc_ctrl->mem_size >> PAGE_SHIFT)
  56                 return -EINVAL;
  57
  58         /* ast2400/2500 AHB accesses are not cache coherent */
  59         prot = pgprot_noncached(prot);
  60
  61         if (remap_pfn_range(vma, vma->vm_start,
  62                 (lpc_ctrl->mem_base >> PAGE_SHIFT) + vma->vm_pgoff,
  63                 vsize, prot))
  64                 return -EAGAIN;
  65
  66         return 0;
  67 }
  68
  69 static long aspeed_lpc_ctrl_ioctl(struct file *file, unsigned int cmd,
  70                 unsigned long param)
  71 {
  72         struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
  73         struct device *dev = file->private_data;
  74         void __user *p = (void __user *)param;
  75         struct aspeed_lpc_ctrl_mapping map;
  76         u32 addr;
  77         u32 size;
  78         long rc;
  79
  80         if (copy_from_user(&map, p, sizeof(map)))
  81                 return -EFAULT;
  82
  83         if (map.flags != 0)
  84                 return -EINVAL;
  85
  86         switch (cmd) {
  87         case ASPEED_LPC_CTRL_IOCTL_GET_SIZE:
  88                 /* The flash windows don't report their size */
  89                 if (map.window_type != ASPEED_LPC_CTRL_WINDOW_MEMORY)
  90                         return -EINVAL;
  91
  92                 /* Support more than one window id in the future */
  93                 if (map.window_id != 0)
  94                         return -EINVAL;
  95
  96                 /* If memory-region is not described in device tree */
  97                 if (!lpc_ctrl->mem_size) {
  98                         dev_dbg(dev, "Didn't find reserved memory\n");
  99                         return -ENXIO;
 100                 }
 101
 102                 map.size = lpc_ctrl->mem_size;
 103
 104                 return copy_to_user(p, &map, sizeof(map)) ? -EFAULT : 0;
 105         case ASPEED_LPC_CTRL_IOCTL_MAP:
 106
 107                 /*
 108                  * The top half of HICR7 is the MSB of the BMC address of the
 109                  * mapping.
 110                  * The bottom half of HICR7 is the MSB of the HOST LPC
 111                  * firmware space address of the mapping.
 112                  *
 113                  * The 1 bits in the top of half of HICR8 represent the bits
 114                  * (in the requested address) that should be ignored and
 115                  * replaced with those from the top half of HICR7.
 116                  * The 1 bits in the bottom half of HICR8 represent the bits
 117                  * (in the requested address) that should be kept and pass
 118                  * into the BMC address space.
 119                  */
 120
 121                 /*
 122                  * It doesn't make sense to talk about a size or offset with
 123                  * low 16 bits set. Both HICR7 and HICR8 talk about the top 16
 124                  * bits of addresses and sizes.
 125                  */
 126
 127                 if ((map.size & 0x0000ffff) || (map.offset & 0x0000ffff))
 128                         return -EINVAL;
 129
 130                 /*
 131                  * Because of the way the masks work in HICR8 offset has to
 132                  * be a multiple of size.
 133                  */
 134                 if (map.offset & (map.size - 1))
 135                         return -EINVAL;
 136
 137                 if (map.window_type == ASPEED_LPC_CTRL_WINDOW_FLASH) {
 138                         if (!lpc_ctrl->pnor_size) {
 139                                 dev_dbg(dev, "Didn't find host pnor flash\n");
 140                                 return -ENXIO;
 141                         }
 142                         addr = lpc_ctrl->pnor_base;
 143                         size = lpc_ctrl->pnor_size;
 144                 } else if (map.window_type == ASPEED_LPC_CTRL_WINDOW_MEMORY) {
 145                         /* If memory-region is not described in device tree */
 146                         if (!lpc_ctrl->mem_size) {
 147                                 dev_dbg(dev, "Didn't find reserved memory\n");
 148                                 return -ENXIO;
 149                         }
 150                         addr = lpc_ctrl->mem_base;
 151                         size = lpc_ctrl->mem_size;
 152                 } else {
 153                         return -EINVAL;
 154                 }
 155
 156                 /* Check overflow first! */
 157                 if (map.offset + map.size < map.offset ||
 158                         map.offset + map.size > size)
 159                         return -EINVAL;
 160
 161                 if (map.size == 0 || map.size > size)
 162                         return -EINVAL;
 163
 164                 addr += map.offset;
 165
 166                 /*
 167                  * addr (host lpc address) is safe regardless of values. This
 168                  * simply changes the address the host has to request on its
 169                  * side of the LPC bus. This cannot impact the hosts own
 170                  * memory space by surprise as LPC specific accessors are
 171                  * required. The only strange thing that could be done is
 172                  * setting the lower 16 bits but the shift takes care of that.
 173                  */
 174
 175                 rc = regmap_write(lpc_ctrl->regmap, HICR7,
 176                                 (addr | (map.addr >> 16)));
 177                 if (rc)
 178                         return rc;
 179
 180                 rc = regmap_write(lpc_ctrl->regmap, HICR8,
 181                                 (~(map.size - 1)) | ((map.size >> 16) - 1));
 182                 if (rc)
 183                         return rc;
 184
 185                 /*
 186                  * Switch to FWH2AHB mode, AST2600 only.
 187                  */
 188                 if (lpc_ctrl->fwh2ahb) {
 189                         /*
 190                          * Enable FWH2AHB in SCU debug control register 2. This
 191                          * does not turn it on, but makes it available for it
 192                          * to be configured in HICR6.
 193                          */
 194                         regmap_update_bits(lpc_ctrl->scu, 0x0D8, BIT(2), 0);
 195
 196                         /*
 197                          * The other bits in this register are interrupt status bits
 198                          * that are cleared by writing 1. As we don't want to clear
 199                          * them, set only the bit of interest.
 200                          */
 201                         regmap_write(lpc_ctrl->regmap, HICR6, SW_FWH2AHB);
 202                 }
 203
 204                 /*
 205                  * Enable LPC FHW cycles. This is required for the host to
 206                  * access the regions specified.
 207                  */
 208                 return regmap_update_bits(lpc_ctrl->regmap, HICR5,
 209                                 HICR5_ENFWH | HICR5_ENL2H,
 210                                 HICR5_ENFWH | HICR5_ENL2H);
 211         }
 212
 213         return -EINVAL;
 214 }
 215
 216 static const struct file_operations aspeed_lpc_ctrl_fops = {
 217         .owner          = THIS_MODULE,
 218         .mmap           = aspeed_lpc_ctrl_mmap,
 219         .unlocked_ioctl = aspeed_lpc_ctrl_ioctl,
 220 };
 221
 222 static int aspeed_lpc_ctrl_probe(struct platform_device *pdev)
 223 {
 224         struct aspeed_lpc_ctrl *lpc_ctrl;
 225         struct device_node *node;
 226         struct resource resm;
 227         struct device *dev;
 228         struct device_node *np;
 229         int rc;
 230
 231         dev = &pdev->dev;
 232
 233         lpc_ctrl = devm_kzalloc(dev, sizeof(*lpc_ctrl), GFP_KERNEL);
 234         if (!lpc_ctrl)
 235                 return -ENOMEM;
 236
 237         /* If flash is described in device tree then store */
 238         node = of_parse_phandle(dev->of_node, "flash", 0);
 239         if (!node) {
 240                 dev_dbg(dev, "Didn't find host pnor flash node\n");
 241         } else {
 242                 rc = of_address_to_resource(node, 1, &resm);
 243                 of_node_put(node);
 244                 if (rc) {
 245                         dev_err(dev, "Couldn't address to resource for flash\n");
 246                         return rc;
 247                 }
 248
 249                 lpc_ctrl->pnor_size = resource_size(&resm);
 250                 lpc_ctrl->pnor_base = resm.start;
 251         }
 252
 253
 254         dev_set_drvdata(&pdev->dev, lpc_ctrl);
 255
 256         /* If memory-region is described in device tree then store */
 257         node = of_parse_phandle(dev->of_node, "memory-region", 0);
 258         if (!node) {
 259                 dev_dbg(dev, "Didn't find reserved memory\n");
 260         } else {
 261                 rc = of_address_to_resource(node, 0, &resm);
 262                 of_node_put(node);
 263                 if (rc) {
 264                         dev_err(dev, "Couldn't address to resource for reserved memory\n");
 265                         return -ENXIO;
 266                 }
 267
 268                 lpc_ctrl->mem_size = resource_size(&resm);
 269                 lpc_ctrl->mem_base = resm.start;
 270
 271                 if (!is_power_of_2(lpc_ctrl->mem_size)) {
 272                         dev_err(dev, "Reserved memory size must be a power of 2, got %u\n",
 273                                (unsigned int)lpc_ctrl->mem_size);
 274                         return -EINVAL;
 275                 }
 276
 277                 if (!IS_ALIGNED(lpc_ctrl->mem_base, lpc_ctrl->mem_size)) {
 278                         dev_err(dev, "Reserved memory must be naturally aligned for size %u\n",
 279                                (unsigned int)lpc_ctrl->mem_size);
 280                         return -EINVAL;
 281                 }
 282         }
 283
 284         np = pdev->dev.parent->of_node;
 285         if (!of_device_is_compatible(np, "aspeed,ast2400-lpc-v2") &&
 286             !of_device_is_compatible(np, "aspeed,ast2500-lpc-v2") &&
 287             !of_device_is_compatible(np, "aspeed,ast2600-lpc-v2")) {
 288                 dev_err(dev, "unsupported LPC device binding\n");
 289                 return -ENODEV;
 290         }
 291
 292         lpc_ctrl->regmap = syscon_node_to_regmap(np);
 293         if (IS_ERR(lpc_ctrl->regmap)) {
 294                 dev_err(dev, "Couldn't get regmap\n");
 295                 return -ENODEV;
 296         }
 297
 298         if (of_device_is_compatible(dev->of_node, "aspeed,ast2600-lpc-ctrl")) {
 299                 lpc_ctrl->fwh2ahb = true;
 300
 301                 lpc_ctrl->scu = syscon_regmap_lookup_by_compatible("aspeed,ast2600-scu");
 302                 if (IS_ERR(lpc_ctrl->scu)) {
 303                         dev_err(dev, "couldn't find scu\n");
 304                         return PTR_ERR(lpc_ctrl->scu);
 305                 }
 306         }
 307
 308         lpc_ctrl->clk = devm_clk_get(dev, NULL);
 309         if (IS_ERR(lpc_ctrl->clk))
 310                 return dev_err_probe(dev, PTR_ERR(lpc_ctrl->clk),
 311                                      "couldn't get clock\n");
 312         rc = clk_prepare_enable(lpc_ctrl->clk);
 313         if (rc) {
 314                 dev_err(dev, "couldn't enable clock\n");
 315                 return rc;
 316         }
 317
 318         lpc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
 319         lpc_ctrl->miscdev.name = DEVICE_NAME;
 320         lpc_ctrl->miscdev.fops = &aspeed_lpc_ctrl_fops;
 321         lpc_ctrl->miscdev.parent = dev;
 322         rc = misc_register(&lpc_ctrl->miscdev);
 323         if (rc) {
 324                 dev_err(dev, "Unable to register device\n");
 325                 goto err;
 326         }
 327
 328         return 0;
 329
 330 err:
 331         clk_disable_unprepare(lpc_ctrl->clk);
 332         return rc;
 333 }
 334
 335 static void aspeed_lpc_ctrl_remove(struct platform_device *pdev)
 336 {
 337         struct aspeed_lpc_ctrl *lpc_ctrl = dev_get_drvdata(&pdev->dev);
 338
 339         misc_deregister(&lpc_ctrl->miscdev);
 340         clk_disable_unprepare(lpc_ctrl->clk);
 341 }
 342
 343 static const struct of_device_id aspeed_lpc_ctrl_match[] = {
 344         { .compatible = "aspeed,ast2400-lpc-ctrl" },
 345         { .compatible = "aspeed,ast2500-lpc-ctrl" },
 346         { .compatible = "aspeed,ast2600-lpc-ctrl" },
 347         { },
 348 };
 349
 350 static struct platform_driver aspeed_lpc_ctrl_driver = {
 351         .driver = {
 352                 .name           = DEVICE_NAME,
 353                 .of_match_table = aspeed_lpc_ctrl_match,
 354         },
 355         .probe = aspeed_lpc_ctrl_probe,
 356         .remove = aspeed_lpc_ctrl_remove,
 357 };
 358
 359 module_platform_driver(aspeed_lpc_ctrl_driver);
 360
 361 MODULE_DEVICE_TABLE(of, aspeed_lpc_ctrl_match);
 362 MODULE_LICENSE("GPL");
 363 MODULE_AUTHOR("Cyril Bur <cyrilbur@gmail.com>");
 364 MODULE_DESCRIPTION("Control for ASPEED LPC HOST to BMC mappings");