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