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/mfd/syscon.h>
   8 #include <linux/miscdevice.h>
   9 #include <linux/mm.h>
  10 #include <linux/module.h>
  11 #include <linux/of_address.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/poll.h>
  14 #include <linux/regmap.h>
  15
  16 #include <linux/aspeed-lpc-ctrl.h>
  17
  18 #define DEVICE_NAME     "aspeed-lpc-ctrl"
  19
  20 #define HICR5 0x0
  21 #define HICR5_ENL2H     BIT(8)
  22 #define HICR5_ENFWH     BIT(10)
  23
  24 #define HICR7 0x8
  25 #define HICR8 0xc
  26
  27 struct aspeed_lpc_ctrl {
  28         struct miscdevice       miscdev;
  29         struct regmap           *regmap;
  30         struct clk              *clk;
  31         phys_addr_t             mem_base;
  32         resource_size_t         mem_size;
  33         u32             pnor_size;
  34         u32             pnor_base;
  35 };
  36
  37 static struct aspeed_lpc_ctrl *file_aspeed_lpc_ctrl(struct file *file)
  38 {
  39         return container_of(file->private_data, struct aspeed_lpc_ctrl,
  40                         miscdev);
  41 }
  42
  43 static int aspeed_lpc_ctrl_mmap(struct file *file, struct vm_area_struct *vma)
  44 {
  45         struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
  46         unsigned long vsize = vma->vm_end - vma->vm_start;
  47         pgprot_t prot = vma->vm_page_prot;
  48
  49         if (vma->vm_pgoff + vsize > lpc_ctrl->mem_base + lpc_ctrl->mem_size)
  50                 return -EINVAL;
  51
  52         /* ast2400/2500 AHB accesses are not cache coherent */
  53         prot = pgprot_noncached(prot);
  54
  55         if (remap_pfn_range(vma, vma->vm_start,
  56                 (lpc_ctrl->mem_base >> PAGE_SHIFT) + vma->vm_pgoff,
  57                 vsize, prot))
  58                 return -EAGAIN;
  59
  60         return 0;
  61 }
  62
  63 static long aspeed_lpc_ctrl_ioctl(struct file *file, unsigned int cmd,
  64                 unsigned long param)
  65 {
  66         struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
  67         struct device *dev = file->private_data;
  68         void __user *p = (void __user *)param;
  69         struct aspeed_lpc_ctrl_mapping map;
  70         u32 addr;
  71         u32 size;
  72         long rc;
  73
  74         if (copy_from_user(&map, p, sizeof(map)))
  75                 return -EFAULT;
  76
  77         if (map.flags != 0)
  78                 return -EINVAL;
  79
  80         switch (cmd) {
  81         case ASPEED_LPC_CTRL_IOCTL_GET_SIZE:
  82                 /* The flash windows don't report their size */
  83                 if (map.window_type != ASPEED_LPC_CTRL_WINDOW_MEMORY)
  84                         return -EINVAL;
  85
  86                 /* Support more than one window id in the future */
  87                 if (map.window_id != 0)
  88                         return -EINVAL;
  89
  90                 /* If memory-region is not described in device tree */
  91                 if (!lpc_ctrl->mem_size) {
  92                         dev_dbg(dev, "Didn't find reserved memory\n");
  93                         return -ENXIO;
  94                 }
  95
  96                 map.size = lpc_ctrl->mem_size;
  97
  98                 return copy_to_user(p, &map, sizeof(map)) ? -EFAULT : 0;
  99         case ASPEED_LPC_CTRL_IOCTL_MAP:
 100
 101                 /*
 102                  * The top half of HICR7 is the MSB of the BMC address of the
 103                  * mapping.
 104                  * The bottom half of HICR7 is the MSB of the HOST LPC
 105                  * firmware space address of the mapping.
 106                  *
 107                  * The 1 bits in the top of half of HICR8 represent the bits
 108                  * (in the requested address) that should be ignored and
 109                  * replaced with those from the top half of HICR7.
 110                  * The 1 bits in the bottom half of HICR8 represent the bits
 111                  * (in the requested address) that should be kept and pass
 112                  * into the BMC address space.
 113                  */
 114
 115                 /*
 116                  * It doesn't make sense to talk about a size or offset with
 117                  * low 16 bits set. Both HICR7 and HICR8 talk about the top 16
 118                  * bits of addresses and sizes.
 119                  */
 120
 121                 if ((map.size & 0x0000ffff) || (map.offset & 0x0000ffff))
 122                         return -EINVAL;
 123
 124                 /*
 125                  * Because of the way the masks work in HICR8 offset has to
 126                  * be a multiple of size.
 127                  */
 128                 if (map.offset & (map.size - 1))
 129                         return -EINVAL;
 130
 131                 if (map.window_type == ASPEED_LPC_CTRL_WINDOW_FLASH) {
 132                         if (!lpc_ctrl->pnor_size) {
 133                                 dev_dbg(dev, "Didn't find host pnor flash\n");
 134                                 return -ENXIO;
 135                         }
 136                         addr = lpc_ctrl->pnor_base;
 137                         size = lpc_ctrl->pnor_size;
 138                 } else if (map.window_type == ASPEED_LPC_CTRL_WINDOW_MEMORY) {
 139                         /* If memory-region is not described in device tree */
 140                         if (!lpc_ctrl->mem_size) {
 141                                 dev_dbg(dev, "Didn't find reserved memory\n");
 142                                 return -ENXIO;
 143                         }
 144                         addr = lpc_ctrl->mem_base;
 145                         size = lpc_ctrl->mem_size;
 146                 } else {
 147                         return -EINVAL;
 148                 }
 149
 150                 /* Check overflow first! */
 151                 if (map.offset + map.size < map.offset ||
 152                         map.offset + map.size > size)
 153                         return -EINVAL;
 154
 155                 if (map.size == 0 || map.size > size)
 156                         return -EINVAL;
 157
 158                 addr += map.offset;
 159
 160                 /*
 161                  * addr (host lpc address) is safe regardless of values. This
 162                  * simply changes the address the host has to request on its
 163                  * side of the LPC bus. This cannot impact the hosts own
 164                  * memory space by surprise as LPC specific accessors are
 165                  * required. The only strange thing that could be done is
 166                  * setting the lower 16 bits but the shift takes care of that.
 167                  */
 168
 169                 rc = regmap_write(lpc_ctrl->regmap, HICR7,
 170                                 (addr | (map.addr >> 16)));
 171                 if (rc)
 172                         return rc;
 173
 174                 rc = regmap_write(lpc_ctrl->regmap, HICR8,
 175                                 (~(map.size - 1)) | ((map.size >> 16) - 1));
 176                 if (rc)
 177                         return rc;
 178
 179                 /*
 180                  * Enable LPC FHW cycles. This is required for the host to
 181                  * access the regions specified.
 182                  */
 183                 return regmap_update_bits(lpc_ctrl->regmap, HICR5,
 184                                 HICR5_ENFWH | HICR5_ENL2H,
 185                                 HICR5_ENFWH | HICR5_ENL2H);
 186         }
 187
 188         return -EINVAL;
 189 }
 190
 191 static const struct file_operations aspeed_lpc_ctrl_fops = {
 192         .owner          = THIS_MODULE,
 193         .mmap           = aspeed_lpc_ctrl_mmap,
 194         .unlocked_ioctl = aspeed_lpc_ctrl_ioctl,
 195 };
 196
 197 static int aspeed_lpc_ctrl_probe(struct platform_device *pdev)
 198 {
 199         struct aspeed_lpc_ctrl *lpc_ctrl;
 200         struct device_node *node;
 201         struct resource resm;
 202         struct device *dev;
 203         int rc;
 204
 205         dev = &pdev->dev;
 206
 207         lpc_ctrl = devm_kzalloc(dev, sizeof(*lpc_ctrl), GFP_KERNEL);
 208         if (!lpc_ctrl)
 209                 return -ENOMEM;
 210
 211         /* If flash is described in device tree then store */
 212         node = of_parse_phandle(dev->of_node, "flash", 0);
 213         if (!node) {
 214                 dev_dbg(dev, "Didn't find host pnor flash node\n");
 215         } else {
 216                 rc = of_address_to_resource(node, 1, &resm);
 217                 of_node_put(node);
 218                 if (rc) {
 219                         dev_err(dev, "Couldn't address to resource for flash\n");
 220                         return rc;
 221                 }
 222
 223                 lpc_ctrl->pnor_size = resource_size(&resm);
 224                 lpc_ctrl->pnor_base = resm.start;
 225         }
 226
 227
 228         dev_set_drvdata(&pdev->dev, lpc_ctrl);
 229
 230         /* If memory-region is described in device tree then store */
 231         node = of_parse_phandle(dev->of_node, "memory-region", 0);
 232         if (!node) {
 233                 dev_dbg(dev, "Didn't find reserved memory\n");
 234         } else {
 235                 rc = of_address_to_resource(node, 0, &resm);
 236                 of_node_put(node);
 237                 if (rc) {
 238                         dev_err(dev, "Couldn't address to resource for reserved memory\n");
 239                         return -ENXIO;
 240                 }
 241
 242                 lpc_ctrl->mem_size = resource_size(&resm);
 243                 lpc_ctrl->mem_base = resm.start;
 244         }
 245
 246         lpc_ctrl->regmap = syscon_node_to_regmap(
 247                         pdev->dev.parent->of_node);
 248         if (IS_ERR(lpc_ctrl->regmap)) {
 249                 dev_err(dev, "Couldn't get regmap\n");
 250                 return -ENODEV;
 251         }
 252
 253         lpc_ctrl->clk = devm_clk_get(dev, NULL);
 254         if (IS_ERR(lpc_ctrl->clk)) {
 255                 dev_err(dev, "couldn't get clock\n");
 256                 return PTR_ERR(lpc_ctrl->clk);
 257         }
 258         rc = clk_prepare_enable(lpc_ctrl->clk);
 259         if (rc) {
 260                 dev_err(dev, "couldn't enable clock\n");
 261                 return rc;
 262         }
 263
 264         lpc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
 265         lpc_ctrl->miscdev.name = DEVICE_NAME;
 266         lpc_ctrl->miscdev.fops = &aspeed_lpc_ctrl_fops;
 267         lpc_ctrl->miscdev.parent = dev;
 268         rc = misc_register(&lpc_ctrl->miscdev);
 269         if (rc) {
 270                 dev_err(dev, "Unable to register device\n");
 271                 goto err;
 272         }
 273
 274         return 0;
 275
 276 err:
 277         clk_disable_unprepare(lpc_ctrl->clk);
 278         return rc;
 279 }
 280
 281 static int aspeed_lpc_ctrl_remove(struct platform_device *pdev)
 282 {
 283         struct aspeed_lpc_ctrl *lpc_ctrl = dev_get_drvdata(&pdev->dev);
 284
 285         misc_deregister(&lpc_ctrl->miscdev);
 286         clk_disable_unprepare(lpc_ctrl->clk);
 287
 288         return 0;
 289 }
 290
 291 static const struct of_device_id aspeed_lpc_ctrl_match[] = {
 292         { .compatible = "aspeed,ast2400-lpc-ctrl" },
 293         { .compatible = "aspeed,ast2500-lpc-ctrl" },
 294         { },
 295 };
 296
 297 static struct platform_driver aspeed_lpc_ctrl_driver = {
 298         .driver = {
 299                 .name           = DEVICE_NAME,
 300                 .of_match_table = aspeed_lpc_ctrl_match,
 301         },
 302         .probe = aspeed_lpc_ctrl_probe,
 303         .remove = aspeed_lpc_ctrl_remove,
 304 };
 305
 306 module_platform_driver(aspeed_lpc_ctrl_driver);
 307
 308 MODULE_DEVICE_TABLE(of, aspeed_lpc_ctrl_match);
 309 MODULE_LICENSE("GPL");
 310 MODULE_AUTHOR("Cyril Bur <cyrilbur@gmail.com>");
 311 MODULE_DESCRIPTION("Control for aspeed 2400/2500 LPC HOST to BMC mappings");