Commit | Line | Data |
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ca644bd5 MB |
1 | /* |
2 | * RNG driver for Intel RNGs | |
3 | * | |
4 | * Copyright 2005 (c) MontaVista Software, Inc. | |
5 | * | |
6 | * with the majority of the code coming from: | |
7 | * | |
8 | * Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG) | |
9 | * (c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com> | |
10 | * | |
11 | * derived from | |
12 | * | |
13 | * Hardware driver for the AMD 768 Random Number Generator (RNG) | |
77122d0b | 14 | * (c) Copyright 2001 Red Hat Inc |
ca644bd5 MB |
15 | * |
16 | * derived from | |
17 | * | |
18 | * Hardware driver for Intel i810 Random Number Generator (RNG) | |
19 | * Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com> | |
20 | * Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com> | |
21 | * | |
22 | * This file is licensed under the terms of the GNU General Public | |
23 | * License version 2. This program is licensed "as is" without any | |
24 | * warranty of any kind, whether express or implied. | |
25 | */ | |
26 | ||
ee527cd3 | 27 | #include <linux/hw_random.h> |
ca644bd5 | 28 | #include <linux/kernel.h> |
ee527cd3 | 29 | #include <linux/module.h> |
ca644bd5 | 30 | #include <linux/pci.h> |
ee527cd3 | 31 | #include <linux/stop_machine.h> |
984e976f | 32 | #include <linux/delay.h> |
ca644bd5 MB |
33 | #include <asm/io.h> |
34 | ||
35 | ||
36 | #define PFX KBUILD_MODNAME ": " | |
37 | ||
38 | /* | |
39 | * RNG registers | |
40 | */ | |
41 | #define INTEL_RNG_HW_STATUS 0 | |
42 | #define INTEL_RNG_PRESENT 0x40 | |
43 | #define INTEL_RNG_ENABLED 0x01 | |
44 | #define INTEL_RNG_STATUS 1 | |
45 | #define INTEL_RNG_DATA_PRESENT 0x01 | |
46 | #define INTEL_RNG_DATA 2 | |
47 | ||
48 | /* | |
49 | * Magic address at which Intel PCI bridges locate the RNG | |
50 | */ | |
51 | #define INTEL_RNG_ADDR 0xFFBC015F | |
52 | #define INTEL_RNG_ADDR_LEN 3 | |
53 | ||
c24c95a0 JB |
54 | /* |
55 | * LPC bridge PCI config space registers | |
56 | */ | |
57 | #define FWH_DEC_EN1_REG_OLD 0xe3 | |
58 | #define FWH_DEC_EN1_REG_NEW 0xd9 /* high byte of 16-bit register */ | |
59 | #define FWH_F8_EN_MASK 0x80 | |
60 | ||
61 | #define BIOS_CNTL_REG_OLD 0x4e | |
62 | #define BIOS_CNTL_REG_NEW 0xdc | |
63 | #define BIOS_CNTL_WRITE_ENABLE_MASK 0x01 | |
64 | #define BIOS_CNTL_LOCK_ENABLE_MASK 0x02 | |
65 | ||
66 | /* | |
67 | * Magic address at which Intel Firmware Hubs get accessed | |
68 | */ | |
69 | #define INTEL_FWH_ADDR 0xffff0000 | |
70 | #define INTEL_FWH_ADDR_LEN 2 | |
71 | ||
72 | /* | |
73 | * Intel Firmware Hub command codes (write to any address inside the device) | |
74 | */ | |
75 | #define INTEL_FWH_RESET_CMD 0xff /* aka READ_ARRAY */ | |
76 | #define INTEL_FWH_READ_ID_CMD 0x90 | |
77 | ||
78 | /* | |
79 | * Intel Firmware Hub Read ID command result addresses | |
80 | */ | |
81 | #define INTEL_FWH_MANUFACTURER_CODE_ADDRESS 0x000000 | |
82 | #define INTEL_FWH_DEVICE_CODE_ADDRESS 0x000001 | |
83 | ||
84 | /* | |
85 | * Intel Firmware Hub Read ID command result values | |
86 | */ | |
87 | #define INTEL_FWH_MANUFACTURER_CODE 0x89 | |
88 | #define INTEL_FWH_DEVICE_CODE_8M 0xac | |
89 | #define INTEL_FWH_DEVICE_CODE_4M 0xad | |
90 | ||
ca644bd5 MB |
91 | /* |
92 | * Data for PCI driver interface | |
93 | * | |
94 | * This data only exists for exporting the supported | |
95 | * PCI ids via MODULE_DEVICE_TABLE. We do not actually | |
96 | * register a pci_driver, because someone else might one day | |
97 | * want to register another driver on the same PCI id. | |
98 | */ | |
99 | static const struct pci_device_id pci_tbl[] = { | |
c24c95a0 | 100 | /* AA |
29d73aab JS |
101 | { PCI_DEVICE(0x8086, 0x2418) }, */ |
102 | { PCI_DEVICE(0x8086, 0x2410) }, /* AA */ | |
c24c95a0 | 103 | /* AB |
29d73aab JS |
104 | { PCI_DEVICE(0x8086, 0x2428) }, */ |
105 | { PCI_DEVICE(0x8086, 0x2420) }, /* AB */ | |
c24c95a0 | 106 | /* ?? |
29d73aab | 107 | { PCI_DEVICE(0x8086, 0x2430) }, */ |
c24c95a0 | 108 | /* BAM, CAM, DBM, FBM, GxM |
29d73aab JS |
109 | { PCI_DEVICE(0x8086, 0x2448) }, */ |
110 | { PCI_DEVICE(0x8086, 0x244c) }, /* BAM */ | |
111 | { PCI_DEVICE(0x8086, 0x248c) }, /* CAM */ | |
112 | { PCI_DEVICE(0x8086, 0x24cc) }, /* DBM */ | |
113 | { PCI_DEVICE(0x8086, 0x2641) }, /* FBM */ | |
114 | { PCI_DEVICE(0x8086, 0x27b9) }, /* GxM */ | |
115 | { PCI_DEVICE(0x8086, 0x27bd) }, /* GxM DH */ | |
c24c95a0 | 116 | /* BA, CA, DB, Ex, 6300, Fx, 631x/632x, Gx |
29d73aab JS |
117 | { PCI_DEVICE(0x8086, 0x244e) }, */ |
118 | { PCI_DEVICE(0x8086, 0x2440) }, /* BA */ | |
119 | { PCI_DEVICE(0x8086, 0x2480) }, /* CA */ | |
120 | { PCI_DEVICE(0x8086, 0x24c0) }, /* DB */ | |
121 | { PCI_DEVICE(0x8086, 0x24d0) }, /* Ex */ | |
122 | { PCI_DEVICE(0x8086, 0x25a1) }, /* 6300 */ | |
123 | { PCI_DEVICE(0x8086, 0x2640) }, /* Fx */ | |
124 | { PCI_DEVICE(0x8086, 0x2670) }, /* 631x/632x */ | |
125 | { PCI_DEVICE(0x8086, 0x2671) }, /* 631x/632x */ | |
126 | { PCI_DEVICE(0x8086, 0x2672) }, /* 631x/632x */ | |
127 | { PCI_DEVICE(0x8086, 0x2673) }, /* 631x/632x */ | |
128 | { PCI_DEVICE(0x8086, 0x2674) }, /* 631x/632x */ | |
129 | { PCI_DEVICE(0x8086, 0x2675) }, /* 631x/632x */ | |
130 | { PCI_DEVICE(0x8086, 0x2676) }, /* 631x/632x */ | |
131 | { PCI_DEVICE(0x8086, 0x2677) }, /* 631x/632x */ | |
132 | { PCI_DEVICE(0x8086, 0x2678) }, /* 631x/632x */ | |
133 | { PCI_DEVICE(0x8086, 0x2679) }, /* 631x/632x */ | |
134 | { PCI_DEVICE(0x8086, 0x267a) }, /* 631x/632x */ | |
135 | { PCI_DEVICE(0x8086, 0x267b) }, /* 631x/632x */ | |
136 | { PCI_DEVICE(0x8086, 0x267c) }, /* 631x/632x */ | |
137 | { PCI_DEVICE(0x8086, 0x267d) }, /* 631x/632x */ | |
138 | { PCI_DEVICE(0x8086, 0x267e) }, /* 631x/632x */ | |
139 | { PCI_DEVICE(0x8086, 0x267f) }, /* 631x/632x */ | |
140 | { PCI_DEVICE(0x8086, 0x27b8) }, /* Gx */ | |
c24c95a0 | 141 | /* E |
29d73aab JS |
142 | { PCI_DEVICE(0x8086, 0x245e) }, */ |
143 | { PCI_DEVICE(0x8086, 0x2450) }, /* E */ | |
ca644bd5 MB |
144 | { 0, }, /* terminate list */ |
145 | }; | |
146 | MODULE_DEVICE_TABLE(pci, pci_tbl); | |
147 | ||
9863be59 JB |
148 | static __initdata int no_fwh_detect; |
149 | module_param(no_fwh_detect, int, 0); | |
150 | MODULE_PARM_DESC(no_fwh_detect, "Skip FWH detection:\n" | |
151 | " positive value - skip if FWH space locked read-only\n" | |
152 | " negative value - skip always"); | |
ca644bd5 MB |
153 | |
154 | static inline u8 hwstatus_get(void __iomem *mem) | |
155 | { | |
156 | return readb(mem + INTEL_RNG_HW_STATUS); | |
157 | } | |
158 | ||
159 | static inline u8 hwstatus_set(void __iomem *mem, | |
160 | u8 hw_status) | |
161 | { | |
162 | writeb(hw_status, mem + INTEL_RNG_HW_STATUS); | |
163 | return hwstatus_get(mem); | |
164 | } | |
165 | ||
984e976f | 166 | static int intel_rng_data_present(struct hwrng *rng, int wait) |
ca644bd5 MB |
167 | { |
168 | void __iomem *mem = (void __iomem *)rng->priv; | |
984e976f PM |
169 | int data, i; |
170 | ||
171 | for (i = 0; i < 20; i++) { | |
172 | data = !!(readb(mem + INTEL_RNG_STATUS) & | |
173 | INTEL_RNG_DATA_PRESENT); | |
174 | if (data || !wait) | |
175 | break; | |
176 | udelay(10); | |
177 | } | |
178 | return data; | |
ca644bd5 MB |
179 | } |
180 | ||
181 | static int intel_rng_data_read(struct hwrng *rng, u32 *data) | |
182 | { | |
183 | void __iomem *mem = (void __iomem *)rng->priv; | |
184 | ||
185 | *data = readb(mem + INTEL_RNG_DATA); | |
186 | ||
187 | return 1; | |
188 | } | |
189 | ||
190 | static int intel_rng_init(struct hwrng *rng) | |
191 | { | |
192 | void __iomem *mem = (void __iomem *)rng->priv; | |
193 | u8 hw_status; | |
194 | int err = -EIO; | |
195 | ||
196 | hw_status = hwstatus_get(mem); | |
197 | /* turn RNG h/w on, if it's off */ | |
198 | if ((hw_status & INTEL_RNG_ENABLED) == 0) | |
199 | hw_status = hwstatus_set(mem, hw_status | INTEL_RNG_ENABLED); | |
200 | if ((hw_status & INTEL_RNG_ENABLED) == 0) { | |
201 | printk(KERN_ERR PFX "cannot enable RNG, aborting\n"); | |
202 | goto out; | |
203 | } | |
204 | err = 0; | |
205 | out: | |
206 | return err; | |
207 | } | |
208 | ||
209 | static void intel_rng_cleanup(struct hwrng *rng) | |
210 | { | |
211 | void __iomem *mem = (void __iomem *)rng->priv; | |
212 | u8 hw_status; | |
213 | ||
214 | hw_status = hwstatus_get(mem); | |
215 | if (hw_status & INTEL_RNG_ENABLED) | |
216 | hwstatus_set(mem, hw_status & ~INTEL_RNG_ENABLED); | |
217 | else | |
218 | printk(KERN_WARNING PFX "unusual: RNG already disabled\n"); | |
219 | } | |
220 | ||
221 | ||
222 | static struct hwrng intel_rng = { | |
223 | .name = "intel", | |
224 | .init = intel_rng_init, | |
225 | .cleanup = intel_rng_cleanup, | |
226 | .data_present = intel_rng_data_present, | |
227 | .data_read = intel_rng_data_read, | |
228 | }; | |
229 | ||
ee527cd3 PB |
230 | struct intel_rng_hw { |
231 | struct pci_dev *dev; | |
232 | void __iomem *mem; | |
233 | u8 bios_cntl_off; | |
234 | u8 bios_cntl_val; | |
235 | u8 fwh_dec_en1_off; | |
236 | u8 fwh_dec_en1_val; | |
237 | }; | |
ca644bd5 | 238 | |
ee527cd3 PB |
239 | static int __init intel_rng_hw_init(void *_intel_rng_hw) |
240 | { | |
241 | struct intel_rng_hw *intel_rng_hw = _intel_rng_hw; | |
242 | u8 mfc, dvc; | |
243 | ||
9b1a4d38 | 244 | /* interrupts disabled in stop_machine call */ |
ee527cd3 PB |
245 | |
246 | if (!(intel_rng_hw->fwh_dec_en1_val & FWH_F8_EN_MASK)) | |
247 | pci_write_config_byte(intel_rng_hw->dev, | |
248 | intel_rng_hw->fwh_dec_en1_off, | |
249 | intel_rng_hw->fwh_dec_en1_val | | |
250 | FWH_F8_EN_MASK); | |
251 | if (!(intel_rng_hw->bios_cntl_val & BIOS_CNTL_WRITE_ENABLE_MASK)) | |
252 | pci_write_config_byte(intel_rng_hw->dev, | |
253 | intel_rng_hw->bios_cntl_off, | |
254 | intel_rng_hw->bios_cntl_val | | |
255 | BIOS_CNTL_WRITE_ENABLE_MASK); | |
256 | ||
257 | writeb(INTEL_FWH_RESET_CMD, intel_rng_hw->mem); | |
258 | writeb(INTEL_FWH_READ_ID_CMD, intel_rng_hw->mem); | |
259 | mfc = readb(intel_rng_hw->mem + INTEL_FWH_MANUFACTURER_CODE_ADDRESS); | |
260 | dvc = readb(intel_rng_hw->mem + INTEL_FWH_DEVICE_CODE_ADDRESS); | |
261 | writeb(INTEL_FWH_RESET_CMD, intel_rng_hw->mem); | |
262 | ||
263 | if (!(intel_rng_hw->bios_cntl_val & | |
264 | (BIOS_CNTL_LOCK_ENABLE_MASK|BIOS_CNTL_WRITE_ENABLE_MASK))) | |
265 | pci_write_config_byte(intel_rng_hw->dev, | |
266 | intel_rng_hw->bios_cntl_off, | |
267 | intel_rng_hw->bios_cntl_val); | |
268 | if (!(intel_rng_hw->fwh_dec_en1_val & FWH_F8_EN_MASK)) | |
269 | pci_write_config_byte(intel_rng_hw->dev, | |
270 | intel_rng_hw->fwh_dec_en1_off, | |
271 | intel_rng_hw->fwh_dec_en1_val); | |
c24c95a0 | 272 | |
ee527cd3 PB |
273 | if (mfc != INTEL_FWH_MANUFACTURER_CODE || |
274 | (dvc != INTEL_FWH_DEVICE_CODE_8M && | |
275 | dvc != INTEL_FWH_DEVICE_CODE_4M)) { | |
c97aee9b | 276 | printk(KERN_NOTICE PFX "FWH not detected\n"); |
ee527cd3 PB |
277 | return -ENODEV; |
278 | } | |
279 | ||
280 | return 0; | |
281 | } | |
282 | ||
283 | static int __init intel_init_hw_struct(struct intel_rng_hw *intel_rng_hw, | |
284 | struct pci_dev *dev) | |
c24c95a0 | 285 | { |
ee527cd3 PB |
286 | intel_rng_hw->bios_cntl_val = 0xff; |
287 | intel_rng_hw->fwh_dec_en1_val = 0xff; | |
288 | intel_rng_hw->dev = dev; | |
289 | ||
290 | /* Check for Intel 82802 */ | |
291 | if (dev->device < 0x2640) { | |
292 | intel_rng_hw->fwh_dec_en1_off = FWH_DEC_EN1_REG_OLD; | |
293 | intel_rng_hw->bios_cntl_off = BIOS_CNTL_REG_OLD; | |
294 | } else { | |
295 | intel_rng_hw->fwh_dec_en1_off = FWH_DEC_EN1_REG_NEW; | |
296 | intel_rng_hw->bios_cntl_off = BIOS_CNTL_REG_NEW; | |
297 | } | |
298 | ||
299 | pci_read_config_byte(dev, intel_rng_hw->fwh_dec_en1_off, | |
300 | &intel_rng_hw->fwh_dec_en1_val); | |
301 | pci_read_config_byte(dev, intel_rng_hw->bios_cntl_off, | |
302 | &intel_rng_hw->bios_cntl_val); | |
303 | ||
304 | if ((intel_rng_hw->bios_cntl_val & | |
305 | (BIOS_CNTL_LOCK_ENABLE_MASK|BIOS_CNTL_WRITE_ENABLE_MASK)) | |
306 | == BIOS_CNTL_LOCK_ENABLE_MASK) { | |
307 | static __initdata /*const*/ char warning[] = | |
ad361c98 JP |
308 | KERN_WARNING |
309 | PFX "Firmware space is locked read-only. If you can't or\n" | |
310 | PFX "don't want to disable this in firmware setup, and if\n" | |
311 | PFX "you are certain that your system has a functional\n" | |
312 | PFX "RNG, try using the 'no_fwh_detect' option.\n"; | |
ee527cd3 PB |
313 | |
314 | if (no_fwh_detect) | |
315 | return -ENODEV; | |
316 | printk(warning); | |
317 | return -EBUSY; | |
318 | } | |
319 | ||
320 | intel_rng_hw->mem = ioremap_nocache(INTEL_FWH_ADDR, INTEL_FWH_ADDR_LEN); | |
321 | if (intel_rng_hw->mem == NULL) | |
322 | return -EBUSY; | |
323 | ||
324 | return 0; | |
c24c95a0 | 325 | } |
ee527cd3 | 326 | |
c24c95a0 | 327 | |
ca644bd5 MB |
328 | static int __init mod_init(void) |
329 | { | |
330 | int err = -ENODEV; | |
ee527cd3 | 331 | int i; |
c24c95a0 | 332 | struct pci_dev *dev = NULL; |
ee527cd3 PB |
333 | void __iomem *mem = mem; |
334 | u8 hw_status; | |
335 | struct intel_rng_hw *intel_rng_hw; | |
ca644bd5 | 336 | |
c24c95a0 | 337 | for (i = 0; !dev && pci_tbl[i].vendor; ++i) |
ee527cd3 PB |
338 | dev = pci_get_device(pci_tbl[i].vendor, pci_tbl[i].device, |
339 | NULL); | |
c24c95a0 JB |
340 | |
341 | if (!dev) | |
ca644bd5 MB |
342 | goto out; /* Device not found. */ |
343 | ||
9863be59 JB |
344 | if (no_fwh_detect < 0) { |
345 | pci_dev_put(dev); | |
346 | goto fwh_done; | |
347 | } | |
348 | ||
ee527cd3 PB |
349 | intel_rng_hw = kmalloc(sizeof(*intel_rng_hw), GFP_KERNEL); |
350 | if (!intel_rng_hw) { | |
9863be59 | 351 | pci_dev_put(dev); |
9863be59 JB |
352 | goto out; |
353 | } | |
354 | ||
ee527cd3 PB |
355 | err = intel_init_hw_struct(intel_rng_hw, dev); |
356 | if (err) { | |
c24c95a0 | 357 | pci_dev_put(dev); |
ee527cd3 PB |
358 | kfree(intel_rng_hw); |
359 | if (err == -ENODEV) | |
360 | goto fwh_done; | |
c24c95a0 JB |
361 | goto out; |
362 | } | |
363 | ||
364 | /* | |
365 | * Since the BIOS code/data is going to disappear from its normal | |
366 | * location with the Read ID command, all activity on the system | |
367 | * must be stopped until the state is back to normal. | |
ee527cd3 | 368 | * |
9b1a4d38 | 369 | * Use stop_machine because IPIs can be blocked by disabling |
ee527cd3 | 370 | * interrupts. |
c24c95a0 | 371 | */ |
9b1a4d38 | 372 | err = stop_machine(intel_rng_hw_init, intel_rng_hw, NULL); |
c24c95a0 | 373 | pci_dev_put(dev); |
ee527cd3 PB |
374 | iounmap(intel_rng_hw->mem); |
375 | kfree(intel_rng_hw); | |
376 | if (err) | |
c24c95a0 | 377 | goto out; |
c24c95a0 | 378 | |
9863be59 | 379 | fwh_done: |
ca644bd5 MB |
380 | err = -ENOMEM; |
381 | mem = ioremap(INTEL_RNG_ADDR, INTEL_RNG_ADDR_LEN); | |
382 | if (!mem) | |
383 | goto out; | |
384 | intel_rng.priv = (unsigned long)mem; | |
385 | ||
c24c95a0 | 386 | /* Check for Random Number Generator */ |
ca644bd5 MB |
387 | err = -ENODEV; |
388 | hw_status = hwstatus_get(mem); | |
ee527cd3 PB |
389 | if ((hw_status & INTEL_RNG_PRESENT) == 0) { |
390 | iounmap(mem); | |
391 | goto out; | |
392 | } | |
ca644bd5 MB |
393 | |
394 | printk(KERN_INFO "Intel 82802 RNG detected\n"); | |
395 | err = hwrng_register(&intel_rng); | |
396 | if (err) { | |
397 | printk(KERN_ERR PFX "RNG registering failed (%d)\n", | |
398 | err); | |
ee527cd3 | 399 | iounmap(mem); |
ca644bd5 MB |
400 | } |
401 | out: | |
402 | return err; | |
403 | ||
ca644bd5 MB |
404 | } |
405 | ||
406 | static void __exit mod_exit(void) | |
407 | { | |
408 | void __iomem *mem = (void __iomem *)intel_rng.priv; | |
409 | ||
410 | hwrng_unregister(&intel_rng); | |
411 | iounmap(mem); | |
412 | } | |
413 | ||
56fb5fe9 | 414 | module_init(mod_init); |
ca644bd5 MB |
415 | module_exit(mod_exit); |
416 | ||
417 | MODULE_DESCRIPTION("H/W RNG driver for Intel chipsets"); | |
418 | MODULE_LICENSE("GPL"); |