Christopher Bostic | 680ca6d | 2017-06-06 16:08:56 -0500 | [diff] [blame] | 1 | /* |
| 2 | * SCOM FSI Client device driver |
| 3 | * |
| 4 | * Copyright (C) IBM Corporation 2016 |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERGCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | */ |
| 15 | |
| 16 | #include <linux/fsi.h> |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/cdev.h> |
| 19 | #include <linux/delay.h> |
| 20 | #include <linux/fs.h> |
| 21 | #include <linux/uaccess.h> |
| 22 | #include <linux/slab.h> |
| 23 | #include <linux/miscdevice.h> |
| 24 | #include <linux/list.h> |
| 25 | #include <linux/idr.h> |
| 26 | |
| 27 | #define FSI_ENGID_SCOM 0x5 |
| 28 | |
| 29 | #define SCOM_FSI2PIB_DELAY 50 |
| 30 | |
| 31 | /* SCOM engine register set */ |
| 32 | #define SCOM_DATA0_REG 0x00 |
| 33 | #define SCOM_DATA1_REG 0x04 |
| 34 | #define SCOM_CMD_REG 0x08 |
| 35 | #define SCOM_RESET_REG 0x1C |
| 36 | |
| 37 | #define SCOM_RESET_CMD 0x80000000 |
| 38 | #define SCOM_WRITE_CMD 0x80000000 |
| 39 | |
| 40 | struct scom_device { |
| 41 | struct list_head link; |
| 42 | struct fsi_device *fsi_dev; |
| 43 | struct miscdevice mdev; |
| 44 | char name[32]; |
| 45 | int idx; |
| 46 | }; |
| 47 | |
| 48 | #define to_scom_dev(x) container_of((x), struct scom_device, mdev) |
| 49 | |
| 50 | static struct list_head scom_devices; |
| 51 | |
| 52 | static DEFINE_IDA(scom_ida); |
| 53 | |
| 54 | static int put_scom(struct scom_device *scom_dev, uint64_t value, |
| 55 | uint32_t addr) |
| 56 | { |
| 57 | int rc; |
| 58 | uint32_t data; |
| 59 | |
| 60 | data = cpu_to_be32(SCOM_RESET_CMD); |
| 61 | rc = fsi_device_write(scom_dev->fsi_dev, SCOM_RESET_REG, &data, |
| 62 | sizeof(uint32_t)); |
| 63 | if (rc) |
| 64 | return rc; |
| 65 | |
| 66 | data = cpu_to_be32((value >> 32) & 0xffffffff); |
| 67 | rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA0_REG, &data, |
| 68 | sizeof(uint32_t)); |
| 69 | if (rc) |
| 70 | return rc; |
| 71 | |
| 72 | data = cpu_to_be32(value & 0xffffffff); |
| 73 | rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA1_REG, &data, |
| 74 | sizeof(uint32_t)); |
| 75 | if (rc) |
| 76 | return rc; |
| 77 | |
| 78 | data = cpu_to_be32(SCOM_WRITE_CMD | addr); |
| 79 | return fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data, |
| 80 | sizeof(uint32_t)); |
| 81 | } |
| 82 | |
| 83 | static int get_scom(struct scom_device *scom_dev, uint64_t *value, |
| 84 | uint32_t addr) |
| 85 | { |
| 86 | uint32_t result, data; |
| 87 | int rc; |
| 88 | |
| 89 | *value = 0ULL; |
| 90 | data = cpu_to_be32(addr); |
| 91 | rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data, |
| 92 | sizeof(uint32_t)); |
| 93 | if (rc) |
| 94 | return rc; |
| 95 | |
| 96 | rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA0_REG, &result, |
| 97 | sizeof(uint32_t)); |
| 98 | if (rc) |
| 99 | return rc; |
| 100 | |
| 101 | *value |= (uint64_t)cpu_to_be32(result) << 32; |
| 102 | rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA1_REG, &result, |
| 103 | sizeof(uint32_t)); |
| 104 | if (rc) |
| 105 | return rc; |
| 106 | |
| 107 | *value |= cpu_to_be32(result); |
| 108 | |
| 109 | return 0; |
| 110 | } |
| 111 | |
| 112 | static ssize_t scom_read(struct file *filep, char __user *buf, size_t len, |
| 113 | loff_t *offset) |
| 114 | { |
| 115 | int rc; |
| 116 | struct miscdevice *mdev = |
| 117 | (struct miscdevice *)filep->private_data; |
| 118 | struct scom_device *scom = to_scom_dev(mdev); |
| 119 | struct device *dev = &scom->fsi_dev->dev; |
| 120 | uint64_t val; |
| 121 | |
| 122 | if (len != sizeof(uint64_t)) |
| 123 | return -EINVAL; |
| 124 | |
| 125 | rc = get_scom(scom, &val, *offset); |
| 126 | if (rc) { |
| 127 | dev_dbg(dev, "get_scom fail:%d\n", rc); |
| 128 | return rc; |
| 129 | } |
| 130 | |
| 131 | rc = copy_to_user(buf, &val, len); |
| 132 | if (rc) |
| 133 | dev_dbg(dev, "copy to user failed:%d\n", rc); |
| 134 | |
| 135 | return rc ? rc : len; |
| 136 | } |
| 137 | |
| 138 | static ssize_t scom_write(struct file *filep, const char __user *buf, |
| 139 | size_t len, loff_t *offset) |
| 140 | { |
| 141 | int rc; |
| 142 | struct miscdevice *mdev = filep->private_data; |
| 143 | struct scom_device *scom = to_scom_dev(mdev); |
| 144 | struct device *dev = &scom->fsi_dev->dev; |
| 145 | uint64_t val; |
| 146 | |
| 147 | if (len != sizeof(uint64_t)) |
| 148 | return -EINVAL; |
| 149 | |
| 150 | rc = copy_from_user(&val, buf, len); |
| 151 | if (rc) { |
| 152 | dev_dbg(dev, "copy from user failed:%d\n", rc); |
| 153 | return -EINVAL; |
| 154 | } |
| 155 | |
| 156 | rc = put_scom(scom, val, *offset); |
| 157 | if (rc) { |
| 158 | dev_dbg(dev, "put_scom failed with:%d\n", rc); |
| 159 | return rc; |
| 160 | } |
| 161 | |
| 162 | return len; |
| 163 | } |
| 164 | |
| 165 | static loff_t scom_llseek(struct file *file, loff_t offset, int whence) |
| 166 | { |
| 167 | switch (whence) { |
| 168 | case SEEK_CUR: |
| 169 | break; |
| 170 | case SEEK_SET: |
| 171 | file->f_pos = offset; |
| 172 | break; |
| 173 | default: |
| 174 | return -EINVAL; |
| 175 | } |
| 176 | |
| 177 | return offset; |
| 178 | } |
| 179 | |
| 180 | static const struct file_operations scom_fops = { |
| 181 | .owner = THIS_MODULE, |
| 182 | .llseek = scom_llseek, |
| 183 | .read = scom_read, |
| 184 | .write = scom_write, |
| 185 | }; |
| 186 | |
| 187 | static int scom_probe(struct device *dev) |
| 188 | { |
| 189 | struct fsi_device *fsi_dev = to_fsi_dev(dev); |
| 190 | struct scom_device *scom; |
| 191 | |
| 192 | scom = devm_kzalloc(dev, sizeof(*scom), GFP_KERNEL); |
| 193 | if (!scom) |
| 194 | return -ENOMEM; |
| 195 | |
| 196 | scom->idx = ida_simple_get(&scom_ida, 1, INT_MAX, GFP_KERNEL); |
| 197 | snprintf(scom->name, sizeof(scom->name), "scom%d", scom->idx); |
| 198 | scom->fsi_dev = fsi_dev; |
| 199 | scom->mdev.minor = MISC_DYNAMIC_MINOR; |
| 200 | scom->mdev.fops = &scom_fops; |
| 201 | scom->mdev.name = scom->name; |
| 202 | scom->mdev.parent = dev; |
| 203 | list_add(&scom->link, &scom_devices); |
| 204 | |
| 205 | return misc_register(&scom->mdev); |
| 206 | } |
| 207 | |
| 208 | static int scom_remove(struct device *dev) |
| 209 | { |
| 210 | struct scom_device *scom, *scom_tmp; |
| 211 | struct fsi_device *fsi_dev = to_fsi_dev(dev); |
| 212 | |
| 213 | list_for_each_entry_safe(scom, scom_tmp, &scom_devices, link) { |
| 214 | if (scom->fsi_dev == fsi_dev) { |
| 215 | list_del(&scom->link); |
| 216 | ida_simple_remove(&scom_ida, scom->idx); |
| 217 | misc_deregister(&scom->mdev); |
| 218 | } |
| 219 | } |
| 220 | |
| 221 | return 0; |
| 222 | } |
| 223 | |
| 224 | static struct fsi_device_id scom_ids[] = { |
| 225 | { |
| 226 | .engine_type = FSI_ENGID_SCOM, |
| 227 | .version = FSI_VERSION_ANY, |
| 228 | }, |
| 229 | { 0 } |
| 230 | }; |
| 231 | |
| 232 | static struct fsi_driver scom_drv = { |
| 233 | .id_table = scom_ids, |
| 234 | .drv = { |
| 235 | .name = "scom", |
| 236 | .bus = &fsi_bus_type, |
| 237 | .probe = scom_probe, |
| 238 | .remove = scom_remove, |
| 239 | } |
| 240 | }; |
| 241 | |
| 242 | static int scom_init(void) |
| 243 | { |
| 244 | INIT_LIST_HEAD(&scom_devices); |
| 245 | return fsi_driver_register(&scom_drv); |
| 246 | } |
| 247 | |
| 248 | static void scom_exit(void) |
| 249 | { |
| 250 | struct list_head *pos; |
| 251 | struct scom_device *scom; |
| 252 | |
| 253 | list_for_each(pos, &scom_devices) { |
| 254 | scom = list_entry(pos, struct scom_device, link); |
| 255 | misc_deregister(&scom->mdev); |
| 256 | devm_kfree(&scom->fsi_dev->dev, scom); |
| 257 | } |
| 258 | fsi_driver_unregister(&scom_drv); |
| 259 | } |
| 260 | |
| 261 | module_init(scom_init); |
| 262 | module_exit(scom_exit); |
| 263 | MODULE_LICENSE("GPL"); |