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 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         void __user *p = (void __user *)param;
  68         struct aspeed_lpc_ctrl_mapping map;
  69         u32 addr;
  70         u32 size;
  71         long rc;
  72
  73         if (copy_from_user(&map, p, sizeof(map)))
  74                 return -EFAULT;
  75
  76         if (map.flags != 0)
  77                 return -EINVAL;
  78
  79         switch (cmd) {
  80         case ASPEED_LPC_CTRL_IOCTL_GET_SIZE:
  81                 /* The flash windows don't report their size */
  82                 if (map.window_type != ASPEED_LPC_CTRL_WINDOW_MEMORY)
  83                         return -EINVAL;
  84
  85                 /* Support more than one window id in the future */
  86                 if (map.window_id != 0)
  87                         return -EINVAL;
  88
  89                 map.size = lpc_ctrl->mem_size;
  90
  91                 return copy_to_user(p, &map, sizeof(map)) ? -EFAULT : 0;
  92         case ASPEED_LPC_CTRL_IOCTL_MAP:
  93
  94                 /*
  95                  * The top half of HICR7 is the MSB of the BMC address of the
  96                  * mapping.
  97                  * The bottom half of HICR7 is the MSB of the HOST LPC
  98                  * firmware space address of the mapping.
  99                  *
 100                  * The 1 bits in the top of half of HICR8 represent the bits
 101                  * (in the requested address) that should be ignored and
 102                  * replaced with those from the top half of HICR7.
 103                  * The 1 bits in the bottom half of HICR8 represent the bits
 104                  * (in the requested address) that should be kept and pass
 105                  * into the BMC address space.
 106                  */
 107
 108                 /*
 109                  * It doesn't make sense to talk about a size or offset with
 110                  * low 16 bits set. Both HICR7 and HICR8 talk about the top 16
 111                  * bits of addresses and sizes.
 112                  */
 113
 114                 if ((map.size & 0x0000ffff) || (map.offset & 0x0000ffff))
 115                         return -EINVAL;
 116
 117                 /*
 118                  * Because of the way the masks work in HICR8 offset has to
 119                  * be a multiple of size.
 120                  */
 121                 if (map.offset & (map.size - 1))
 122                         return -EINVAL;
 123
 124                 if (map.window_type == ASPEED_LPC_CTRL_WINDOW_FLASH) {
 125                         addr = lpc_ctrl->pnor_base;
 126                         size = lpc_ctrl->pnor_size;
 127                 } else if (map.window_type == ASPEED_LPC_CTRL_WINDOW_MEMORY) {
 128                         addr = lpc_ctrl->mem_base;
 129                         size = lpc_ctrl->mem_size;
 130                 } else {
 131                         return -EINVAL;
 132                 }
 133
 134                 /* Check overflow first! */
 135                 if (map.offset + map.size < map.offset ||
 136                         map.offset + map.size > size)
 137                         return -EINVAL;
 138
 139                 if (map.size == 0 || map.size > size)
 140                         return -EINVAL;
 141
 142                 addr += map.offset;
 143
 144                 /*
 145                  * addr (host lpc address) is safe regardless of values. This
 146                  * simply changes the address the host has to request on its
 147                  * side of the LPC bus. This cannot impact the hosts own
 148                  * memory space by surprise as LPC specific accessors are
 149                  * required. The only strange thing that could be done is
 150                  * setting the lower 16 bits but the shift takes care of that.
 151                  */
 152
 153                 rc = regmap_write(lpc_ctrl->regmap, HICR7,
 154                                 (addr | (map.addr >> 16)));
 155                 if (rc)
 156                         return rc;
 157
 158                 return regmap_write(lpc_ctrl->regmap, HICR8,
 159                         (~(map.size - 1)) | ((map.size >> 16) - 1));
 160         }
 161
 162         return -EINVAL;
 163 }
 164
 165 static const struct file_operations aspeed_lpc_ctrl_fops = {
 166         .owner          = THIS_MODULE,
 167         .mmap           = aspeed_lpc_ctrl_mmap,
 168         .unlocked_ioctl = aspeed_lpc_ctrl_ioctl,
 169 };
 170
 171 static int aspeed_lpc_ctrl_probe(struct platform_device *pdev)
 172 {
 173         struct aspeed_lpc_ctrl *lpc_ctrl;
 174         struct device_node *node;
 175         struct resource resm;
 176         struct device *dev;
 177         int rc;
 178
 179         dev = &pdev->dev;
 180
 181         lpc_ctrl = devm_kzalloc(dev, sizeof(*lpc_ctrl), GFP_KERNEL);
 182         if (!lpc_ctrl)
 183                 return -ENOMEM;
 184
 185         node = of_parse_phandle(dev->of_node, "flash", 0);
 186         if (!node) {
 187                 dev_err(dev, "Didn't find host pnor flash node\n");
 188                 return -ENODEV;
 189         }
 190
 191         rc = of_address_to_resource(node, 1, &resm);
 192         of_node_put(node);
 193         if (rc) {
 194                 dev_err(dev, "Couldn't address to resource for flash\n");
 195                 return rc;
 196         }
 197
 198         lpc_ctrl->pnor_size = resource_size(&resm);
 199         lpc_ctrl->pnor_base = resm.start;
 200
 201         dev_set_drvdata(&pdev->dev, lpc_ctrl);
 202
 203         node = of_parse_phandle(dev->of_node, "memory-region", 0);
 204         if (!node) {
 205                 dev_err(dev, "Didn't find reserved memory\n");
 206                 return -EINVAL;
 207         }
 208
 209         rc = of_address_to_resource(node, 0, &resm);
 210         of_node_put(node);
 211         if (rc) {
 212                 dev_err(dev, "Couldn't address to resource for reserved memory\n");
 213                 return -ENOMEM;
 214         }
 215
 216         lpc_ctrl->mem_size = resource_size(&resm);
 217         lpc_ctrl->mem_base = resm.start;
 218
 219         lpc_ctrl->regmap = syscon_node_to_regmap(
 220                         pdev->dev.parent->of_node);
 221         if (IS_ERR(lpc_ctrl->regmap)) {
 222                 dev_err(dev, "Couldn't get regmap\n");
 223                 return -ENODEV;
 224         }
 225
 226         lpc_ctrl->clk = devm_clk_get(dev, NULL);
 227         if (IS_ERR(lpc_ctrl->clk)) {
 228                 dev_err(dev, "couldn't get clock\n");
 229                 return PTR_ERR(lpc_ctrl->clk);
 230         }
 231         rc = clk_prepare_enable(lpc_ctrl->clk);
 232         if (rc) {
 233                 dev_err(dev, "couldn't enable clock\n");
 234                 return rc;
 235         }
 236
 237         lpc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
 238         lpc_ctrl->miscdev.name = DEVICE_NAME;
 239         lpc_ctrl->miscdev.fops = &aspeed_lpc_ctrl_fops;
 240         lpc_ctrl->miscdev.parent = dev;
 241         rc = misc_register(&lpc_ctrl->miscdev);
 242         if (rc) {
 243                 dev_err(dev, "Unable to register device\n");
 244                 goto err;
 245         }
 246
 247         dev_info(dev, "Loaded at %pr\n", &resm);
 248
 249         return 0;
 250
 251 err:
 252         clk_disable_unprepare(lpc_ctrl->clk);
 253         return rc;
 254 }
 255
 256 static int aspeed_lpc_ctrl_remove(struct platform_device *pdev)
 257 {
 258         struct aspeed_lpc_ctrl *lpc_ctrl = dev_get_drvdata(&pdev->dev);
 259
 260         misc_deregister(&lpc_ctrl->miscdev);
 261         clk_disable_unprepare(lpc_ctrl->clk);
 262
 263         return 0;
 264 }
 265
 266 static const struct of_device_id aspeed_lpc_ctrl_match[] = {
 267         { .compatible = "aspeed,ast2400-lpc-ctrl" },
 268         { .compatible = "aspeed,ast2500-lpc-ctrl" },
 269         { },
 270 };
 271
 272 static struct platform_driver aspeed_lpc_ctrl_driver = {
 273         .driver = {
 274                 .name           = DEVICE_NAME,
 275                 .of_match_table = aspeed_lpc_ctrl_match,
 276         },
 277         .probe = aspeed_lpc_ctrl_probe,
 278         .remove = aspeed_lpc_ctrl_remove,
 279 };
 280
 281 module_platform_driver(aspeed_lpc_ctrl_driver);
 282
 283 MODULE_DEVICE_TABLE(of, aspeed_lpc_ctrl_match);
 284 MODULE_LICENSE("GPL");
 285 MODULE_AUTHOR("Cyril Bur <[email protected]>");
 286 MODULE_DESCRIPTION("Control for aspeed 2400/2500 LPC HOST to BMC mappings");