drivers/firmware/meson/meson_sm.c

   1 /*
   2  * Amlogic Secure Monitor driver
   3  *
   4  * Copyright (C) 2016 Endless Mobile, Inc.
   5  * Author: Carlo Caione <carlo@endlessm.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * version 2 as published by the Free Software Foundation.
  10  *
  11  * You should have received a copy of the GNU General Public License
  12  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  13  */
  14
  15 #define pr_fmt(fmt) "meson-sm: " fmt
  16
  17 #include <linux/arm-smccc.h>
  18 #include <linux/bug.h>
  19 #include <linux/io.h>
  20 #include <linux/module.h>
  21 #include <linux/of.h>
  22 #include <linux/of_device.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/printk.h>
  25 #include <linux/types.h>
  26 #include <linux/sizes.h>
  27  #include <linux/slab.h>
  28
  29 #include <linux/firmware/meson/meson_sm.h>
  30
  31 struct meson_sm_cmd {
  32         unsigned int index;
  33         u32 smc_id;
  34 };
  35 #define CMD(d, s) { .index = (d), .smc_id = (s), }
  36
  37 struct meson_sm_chip {
  38         unsigned int shmem_size;
  39         u32 cmd_shmem_in_base;
  40         u32 cmd_shmem_out_base;
  41         struct meson_sm_cmd cmd[];
  42 };
  43
  44 struct meson_sm_chip gxbb_chip = {
  45         .shmem_size             = SZ_4K,
  46         .cmd_shmem_in_base      = 0x82000020,
  47         .cmd_shmem_out_base     = 0x82000021,
  48         .cmd = {
  49                 CMD(SM_EFUSE_READ,      0x82000030),
  50                 CMD(SM_EFUSE_WRITE,     0x82000031),
  51                 CMD(SM_EFUSE_USER_MAX,  0x82000033),
  52                 CMD(SM_GET_CHIP_ID,     0x82000044),
  53                 { /* sentinel */ },
  54         },
  55 };
  56
  57 struct meson_sm_firmware {
  58         const struct meson_sm_chip *chip;
  59         void __iomem *sm_shmem_in_base;
  60         void __iomem *sm_shmem_out_base;
  61 };
  62
  63 static struct meson_sm_firmware fw;
  64
  65 static u32 meson_sm_get_cmd(const struct meson_sm_chip *chip,
  66                             unsigned int cmd_index)
  67 {
  68         const struct meson_sm_cmd *cmd = chip->cmd;
  69
  70         while (cmd->smc_id && cmd->index != cmd_index)
  71                 cmd++;
  72
  73         return cmd->smc_id;
  74 }
  75
  76 static u32 __meson_sm_call(u32 cmd, u32 arg0, u32 arg1, u32 arg2,
  77                            u32 arg3, u32 arg4)
  78 {
  79         struct arm_smccc_res res;
  80
  81         arm_smccc_smc(cmd, arg0, arg1, arg2, arg3, arg4, 0, 0, &res);
  82         return res.a0;
  83 }
  84
  85 static void __iomem *meson_sm_map_shmem(u32 cmd_shmem, unsigned int size)
  86 {
  87         u32 sm_phy_base;
  88
  89         sm_phy_base = __meson_sm_call(cmd_shmem, 0, 0, 0, 0, 0);
  90         if (!sm_phy_base)
  91                 return 0;
  92
  93         return ioremap_cache(sm_phy_base, size);
  94 }
  95
  96 /**
  97  * meson_sm_call - generic SMC32 call to the secure-monitor
  98  *
  99  * @cmd_index:  Index of the SMC32 function ID
 100  * @ret:        Returned value
 101  * @arg0:       SMC32 Argument 0
 102  * @arg1:       SMC32 Argument 1
 103  * @arg2:       SMC32 Argument 2
 104  * @arg3:       SMC32 Argument 3
 105  * @arg4:       SMC32 Argument 4
 106  *
 107  * Return:      0 on success, a negative value on error
 108  */
 109 int meson_sm_call(unsigned int cmd_index, u32 *ret, u32 arg0,
 110                   u32 arg1, u32 arg2, u32 arg3, u32 arg4)
 111 {
 112         u32 cmd, lret;
 113
 114         if (!fw.chip)
 115                 return -ENOENT;
 116
 117         cmd = meson_sm_get_cmd(fw.chip, cmd_index);
 118         if (!cmd)
 119                 return -EINVAL;
 120
 121         lret = __meson_sm_call(cmd, arg0, arg1, arg2, arg3, arg4);
 122
 123         if (ret)
 124                 *ret = lret;
 125
 126         return 0;
 127 }
 128 EXPORT_SYMBOL(meson_sm_call);
 129
 130 /**
 131  * meson_sm_call_read - retrieve data from secure-monitor
 132  *
 133  * @buffer:     Buffer to store the retrieved data
 134  * @bsize:      Size of the buffer
 135  * @cmd_index:  Index of the SMC32 function ID
 136  * @arg0:       SMC32 Argument 0
 137  * @arg1:       SMC32 Argument 1
 138  * @arg2:       SMC32 Argument 2
 139  * @arg3:       SMC32 Argument 3
 140  * @arg4:       SMC32 Argument 4
 141  *
 142  * Return:      size of read data on success, a negative value on error
 143  *              When 0 is returned there is no guarantee about the amount of
 144  *              data read and bsize bytes are copied in buffer.
 145  */
 146 int meson_sm_call_read(void *buffer, unsigned int bsize, unsigned int cmd_index,
 147                        u32 arg0, u32 arg1, u32 arg2, u32 arg3, u32 arg4)
 148 {
 149         u32 size;
 150         int ret;
 151
 152         if (!fw.chip)
 153                 return -ENOENT;
 154
 155         if (!fw.chip->cmd_shmem_out_base)
 156                 return -EINVAL;
 157
 158         if (bsize > fw.chip->shmem_size)
 159                 return -EINVAL;
 160
 161         if (meson_sm_call(cmd_index, &size, arg0, arg1, arg2, arg3, arg4) < 0)
 162                 return -EINVAL;
 163
 164         if (size > bsize)
 165                 return -EINVAL;
 166
 167         ret = size;
 168
 169         if (!size)
 170                 size = bsize;
 171
 172         if (buffer)
 173                 memcpy(buffer, fw.sm_shmem_out_base, size);
 174
 175         return ret;
 176 }
 177 EXPORT_SYMBOL(meson_sm_call_read);
 178
 179 /**
 180  * meson_sm_call_write - send data to secure-monitor
 181  *
 182  * @buffer:     Buffer containing data to send
 183  * @size:       Size of the data to send
 184  * @cmd_index:  Index of the SMC32 function ID
 185  * @arg0:       SMC32 Argument 0
 186  * @arg1:       SMC32 Argument 1
 187  * @arg2:       SMC32 Argument 2
 188  * @arg3:       SMC32 Argument 3
 189  * @arg4:       SMC32 Argument 4
 190  *
 191  * Return:      size of sent data on success, a negative value on error
 192  */
 193 int meson_sm_call_write(void *buffer, unsigned int size, unsigned int cmd_index,
 194                         u32 arg0, u32 arg1, u32 arg2, u32 arg3, u32 arg4)
 195 {
 196         u32 written;
 197
 198         if (!fw.chip)
 199                 return -ENOENT;
 200
 201         if (size > fw.chip->shmem_size)
 202                 return -EINVAL;
 203
 204         if (!fw.chip->cmd_shmem_in_base)
 205                 return -EINVAL;
 206
 207         memcpy(fw.sm_shmem_in_base, buffer, size);
 208
 209         if (meson_sm_call(cmd_index, &written, arg0, arg1, arg2, arg3, arg4) < 0)
 210                 return -EINVAL;
 211
 212         if (!written)
 213                 return -EINVAL;
 214
 215         return written;
 216 }
 217 EXPORT_SYMBOL(meson_sm_call_write);
 218
 219 #define SM_CHIP_ID_LENGTH       119
 220 #define SM_CHIP_ID_OFFSET       4
 221 #define SM_CHIP_ID_SIZE         12
 222
 223 static ssize_t serial_show(struct device *dev, struct device_attribute *attr,
 224                          char *buf)
 225 {
 226         uint8_t *id_buf;
 227         int ret;
 228
 229         id_buf = kmalloc(SM_CHIP_ID_LENGTH, GFP_KERNEL);
 230         if (!id_buf)
 231                 return -ENOMEM;
 232
 233         ret = meson_sm_call_read(id_buf, SM_CHIP_ID_LENGTH, SM_GET_CHIP_ID,
 234                                  0, 0, 0, 0, 0);
 235         if (ret < 0) {
 236                 kfree(id_buf);
 237                 return ret;
 238         }
 239
 240         ret = sprintf(buf, "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n",
 241                         id_buf[SM_CHIP_ID_OFFSET + 0],
 242                         id_buf[SM_CHIP_ID_OFFSET + 1],
 243                         id_buf[SM_CHIP_ID_OFFSET + 2],
 244                         id_buf[SM_CHIP_ID_OFFSET + 3],
 245                         id_buf[SM_CHIP_ID_OFFSET + 4],
 246                         id_buf[SM_CHIP_ID_OFFSET + 5],
 247                         id_buf[SM_CHIP_ID_OFFSET + 6],
 248                         id_buf[SM_CHIP_ID_OFFSET + 7],
 249                         id_buf[SM_CHIP_ID_OFFSET + 8],
 250                         id_buf[SM_CHIP_ID_OFFSET + 9],
 251                         id_buf[SM_CHIP_ID_OFFSET + 10],
 252                         id_buf[SM_CHIP_ID_OFFSET + 11]);
 253
 254         kfree(id_buf);
 255
 256         return ret;
 257 }
 258
 259 static DEVICE_ATTR_RO(serial);
 260
 261 static struct attribute *meson_sm_sysfs_attributes[] = {
 262         &dev_attr_serial.attr,
 263         NULL,
 264 };
 265
 266 static const struct attribute_group meson_sm_sysfs_attr_group = {
 267         .attrs = meson_sm_sysfs_attributes,
 268 };
 269
 270 static const struct of_device_id meson_sm_ids[] = {
 271         { .compatible = "amlogic,meson-gxbb-sm", .data = &gxbb_chip },
 272         { /* sentinel */ },
 273 };
 274
 275 static int __init meson_sm_probe(struct platform_device *pdev)
 276 {
 277         const struct meson_sm_chip *chip;
 278
 279         chip = of_match_device(meson_sm_ids, &pdev->dev)->data;
 280
 281         if (chip->cmd_shmem_in_base) {
 282                 fw.sm_shmem_in_base = meson_sm_map_shmem(chip->cmd_shmem_in_base,
 283                                                          chip->shmem_size);
 284                 if (WARN_ON(!fw.sm_shmem_in_base))
 285                         goto out;
 286         }
 287
 288         if (chip->cmd_shmem_out_base) {
 289                 fw.sm_shmem_out_base = meson_sm_map_shmem(chip->cmd_shmem_out_base,
 290                                                           chip->shmem_size);
 291                 if (WARN_ON(!fw.sm_shmem_out_base))
 292                         goto out_in_base;
 293         }
 294
 295         fw.chip = chip;
 296         pr_info("secure-monitor enabled\n");
 297
 298         if (sysfs_create_group(&pdev->dev.kobj, &meson_sm_sysfs_attr_group))
 299                 goto out_in_base;
 300
 301         return 0;
 302
 303 out_in_base:
 304         iounmap(fw.sm_shmem_in_base);
 305 out:
 306         return -EINVAL;
 307 }
 308
 309 static struct platform_driver meson_sm_driver = {
 310         .driver = {
 311                 .name = "meson-sm",
 312                 .of_match_table = of_match_ptr(meson_sm_ids),
 313         },
 314 };
 315 module_platform_driver_probe(meson_sm_driver, meson_sm_probe);