drivers/misc/aspeed-lpc-ctrl.c

   1 /*
   2  * Copyright 2017 IBM Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version
   7  * 2 of the License, or (at your option) any later version.
   8  */
   9
  10 #include <linux/clk.h>
  11 #include <linux/mfd/syscon.h>
  12 #include <linux/miscdevice.h>
  13 #include <linux/mm.h>
  14 #include <linux/module.h>
  15 #include <linux/of_address.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/poll.h>
  18 #include <linux/regmap.h>
  19
  20 #include <linux/aspeed-lpc-ctrl.h>
  21
  22 #define DEVICE_NAME     "aspeed-lpc-ctrl"
  23
  24 #define HICR5 0x0
  25 #define HICR5_ENL2H     BIT(8)
  26 #define HICR5_ENFWH     BIT(10)
  27
  28 #define HICR7 0x8
  29 #define HICR8 0xc
  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 };
  40
  41 static struct aspeed_lpc_ctrl *file_aspeed_lpc_ctrl(struct file *file)
  42 {
  43         return container_of(file->private_data, struct aspeed_lpc_ctrl,
  44                         miscdev);
  45 }
  46
  47 static int aspeed_lpc_ctrl_mmap(struct file *file, struct vm_area_struct *vma)
  48 {
  49         struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
  50         unsigned long vsize = vma->vm_end - vma->vm_start;
  51         pgprot_t prot = vma->vm_page_prot;
  52
  53         if (vma->vm_pgoff + vsize > lpc_ctrl->mem_base + lpc_ctrl->mem_size)
  54                 return -EINVAL;
  55
  56         /* ast2400/2500 AHB accesses are not cache coherent */
  57         prot = pgprot_noncached(prot);
  58
  59         if (remap_pfn_range(vma, vma->vm_start,
  60                 (lpc_ctrl->mem_base >> PAGE_SHIFT) + vma->vm_pgoff,
  61                 vsize, prot))
  62                 return -EAGAIN;
  63
  64         return 0;
  65 }
  66
  67 static long aspeed_lpc_ctrl_ioctl(struct file *file, unsigned int cmd,
  68                 unsigned long param)
  69 {
  70         struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
  71         void __user *p = (void __user *)param;
  72         struct aspeed_lpc_ctrl_mapping map;
  73         u32 addr;
  74         u32 size;
  75         long rc;
  76
  77         if (copy_from_user(&map, p, sizeof(map)))
  78                 return -EFAULT;
  79
  80         if (map.flags != 0)
  81                 return -EINVAL;
  82
  83         switch (cmd) {
  84         case ASPEED_LPC_CTRL_IOCTL_GET_SIZE:
  85                 /* The flash windows don't report their size */
  86                 if (map.window_type != ASPEED_LPC_CTRL_WINDOW_MEMORY)
  87                         return -EINVAL;
  88
  89                 /* Support more than one window id in the future */
  90                 if (map.window_id != 0)
  91                         return -EINVAL;
  92
  93                 map.size = lpc_ctrl->mem_size;
  94
  95                 return copy_to_user(p, &map, sizeof(map)) ? -EFAULT : 0;
  96         case ASPEED_LPC_CTRL_IOCTL_MAP:
  97
  98                 /*
  99                  * The top half of HICR7 is the MSB of the BMC address of the
 100                  * mapping.
 101                  * The bottom half of HICR7 is the MSB of the HOST LPC
 102                  * firmware space address of the mapping.
 103                  *
 104                  * The 1 bits in the top of half of HICR8 represent the bits
 105                  * (in the requested address) that should be ignored and
 106                  * replaced with those from the top half of HICR7.
 107                  * The 1 bits in the bottom half of HICR8 represent the bits
 108                  * (in the requested address) that should be kept and pass
 109                  * into the BMC address space.
 110                  */
 111
 112                 /*
 113                  * It doesn't make sense to talk about a size or offset with
 114                  * low 16 bits set. Both HICR7 and HICR8 talk about the top 16
 115                  * bits of addresses and sizes.
 116                  */
 117
 118                 if ((map.size & 0x0000ffff) || (map.offset & 0x0000ffff))
 119                         return -EINVAL;
 120
 121                 /*
 122                  * Because of the way the masks work in HICR8 offset has to
 123                  * be a multiple of size.
 124                  */
 125                 if (map.offset & (map.size - 1))
 126                         return -EINVAL;
 127
 128                 if (map.window_type == ASPEED_LPC_CTRL_WINDOW_FLASH) {
 129                         addr = lpc_ctrl->pnor_base;
 130                         size = lpc_ctrl->pnor_size;
 131                 } else if (map.window_type == ASPEED_LPC_CTRL_WINDOW_MEMORY) {
 132                         addr = lpc_ctrl->mem_base;
 133                         size = lpc_ctrl->mem_size;
 134                 } else {
 135                         return -EINVAL;
 136                 }
 137
 138                 /* Check overflow first! */
 139                 if (map.offset + map.size < map.offset ||
 140                         map.offset + map.size > size)
 141                         return -EINVAL;
 142
 143                 if (map.size == 0 || map.size > size)
 144                         return -EINVAL;
 145
 146                 addr += map.offset;
 147
 148                 /*
 149                  * addr (host lpc address) is safe regardless of values. This
 150                  * simply changes the address the host has to request on its
 151                  * side of the LPC bus. This cannot impact the hosts own
 152                  * memory space by surprise as LPC specific accessors are
 153                  * required. The only strange thing that could be done is
 154                  * setting the lower 16 bits but the shift takes care of that.
 155                  */
 156
 157                 rc = regmap_write(lpc_ctrl->regmap, HICR7,
 158                                 (addr | (map.addr >> 16)));
 159                 if (rc)
 160                         return rc;
 161
 162                 rc = regmap_write(lpc_ctrl->regmap, HICR8,
 163                                 (~(map.size - 1)) | ((map.size >> 16) - 1));
 164                 if (rc)
 165                         return rc;
 166
 167                 /*
 168                  * Enable LPC FHW cycles. This is required for the host to
 169                  * access the regions specified.
 170                  */
 171                 return regmap_update_bits(lpc_ctrl->regmap, HICR5,
 172                                 HICR5_ENFWH | HICR5_ENL2H,
 173                                 HICR5_ENFWH | HICR5_ENL2H);
 174         }
 175
 176         return -EINVAL;
 177 }
 178
 179 static const struct file_operations aspeed_lpc_ctrl_fops = {
 180         .owner          = THIS_MODULE,
 181         .mmap           = aspeed_lpc_ctrl_mmap,
 182         .unlocked_ioctl = aspeed_lpc_ctrl_ioctl,
 183 };
 184
 185 static int aspeed_lpc_ctrl_probe(struct platform_device *pdev)
 186 {
 187         struct aspeed_lpc_ctrl *lpc_ctrl;
 188         struct device_node *node;
 189         struct resource resm;
 190         struct device *dev;
 191         int rc;
 192
 193         dev = &pdev->dev;
 194
 195         lpc_ctrl = devm_kzalloc(dev, sizeof(*lpc_ctrl), GFP_KERNEL);
 196         if (!lpc_ctrl)
 197                 return -ENOMEM;
 198
 199         node = of_parse_phandle(dev->of_node, "flash", 0);
 200         if (!node) {
 201                 dev_err(dev, "Didn't find host pnor flash node\n");
 202                 return -ENODEV;
 203         }
 204
 205         rc = of_address_to_resource(node, 1, &resm);
 206         of_node_put(node);
 207         if (rc) {
 208                 dev_err(dev, "Couldn't address to resource for flash\n");
 209                 return rc;
 210         }
 211
 212         lpc_ctrl->pnor_size = resource_size(&resm);
 213         lpc_ctrl->pnor_base = resm.start;
 214
 215         dev_set_drvdata(&pdev->dev, lpc_ctrl);
 216
 217         node = of_parse_phandle(dev->of_node, "memory-region", 0);
 218         if (!node) {
 219                 dev_err(dev, "Didn't find reserved memory\n");
 220                 return -EINVAL;
 221         }
 222
 223         rc = of_address_to_resource(node, 0, &resm);
 224         of_node_put(node);
 225         if (rc) {
 226                 dev_err(dev, "Couldn't address to resource for reserved memory\n");
 227                 return -ENOMEM;
 228         }
 229
 230         lpc_ctrl->mem_size = resource_size(&resm);
 231         lpc_ctrl->mem_base = resm.start;
 232
 233         lpc_ctrl->regmap = syscon_node_to_regmap(
 234                         pdev->dev.parent->of_node);
 235         if (IS_ERR(lpc_ctrl->regmap)) {
 236                 dev_err(dev, "Couldn't get regmap\n");
 237                 return -ENODEV;
 238         }
 239
 240         lpc_ctrl->clk = devm_clk_get(dev, NULL);
 241         if (IS_ERR(lpc_ctrl->clk)) {
 242                 dev_err(dev, "couldn't get clock\n");
 243                 return PTR_ERR(lpc_ctrl->clk);
 244         }
 245         rc = clk_prepare_enable(lpc_ctrl->clk);
 246         if (rc) {
 247                 dev_err(dev, "couldn't enable clock\n");
 248                 return rc;
 249         }
 250
 251         lpc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
 252         lpc_ctrl->miscdev.name = DEVICE_NAME;
 253         lpc_ctrl->miscdev.fops = &aspeed_lpc_ctrl_fops;
 254         lpc_ctrl->miscdev.parent = dev;
 255         rc = misc_register(&lpc_ctrl->miscdev);
 256         if (rc) {
 257                 dev_err(dev, "Unable to register device\n");
 258                 goto err;
 259         }
 260
 261         dev_info(dev, "Loaded at %pr\n", &resm);
 262
 263         return 0;
 264
 265 err:
 266         clk_disable_unprepare(lpc_ctrl->clk);
 267         return rc;
 268 }
 269
 270 static int aspeed_lpc_ctrl_remove(struct platform_device *pdev)
 271 {
 272         struct aspeed_lpc_ctrl *lpc_ctrl = dev_get_drvdata(&pdev->dev);
 273
 274         misc_deregister(&lpc_ctrl->miscdev);
 275         clk_disable_unprepare(lpc_ctrl->clk);
 276
 277         return 0;
 278 }
 279
 280 static const struct of_device_id aspeed_lpc_ctrl_match[] = {
 281         { .compatible = "aspeed,ast2400-lpc-ctrl" },
 282         { .compatible = "aspeed,ast2500-lpc-ctrl" },
 283         { },
 284 };
 285
 286 static struct platform_driver aspeed_lpc_ctrl_driver = {
 287         .driver = {
 288                 .name           = DEVICE_NAME,
 289                 .of_match_table = aspeed_lpc_ctrl_match,
 290         },
 291         .probe = aspeed_lpc_ctrl_probe,
 292         .remove = aspeed_lpc_ctrl_remove,
 293 };
 294
 295 module_platform_driver(aspeed_lpc_ctrl_driver);
 296
 297 MODULE_DEVICE_TABLE(of, aspeed_lpc_ctrl_match);
 298 MODULE_LICENSE("GPL");
 299 MODULE_AUTHOR("Cyril Bur <cyrilbur@gmail.com>");
 300 MODULE_DESCRIPTION("Control for aspeed 2400/2500 LPC HOST to BMC mappings");