Pull ec into release branch
[linux-2.6] / drivers / char / hw_random / intel-rng.c
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)
14  * (c) Copyright 2001 Red Hat Inc <alan@redhat.com>
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
27 #include <linux/hw_random.h>
28 #include <linux/kernel.h>
29 #include <linux/module.h>
30 #include <linux/pci.h>
31 #include <linux/stop_machine.h>
32 #include <asm/io.h>
33
34
35 #define PFX     KBUILD_MODNAME ": "
36
37 /*
38  * RNG registers
39  */
40 #define INTEL_RNG_HW_STATUS                     0
41 #define         INTEL_RNG_PRESENT               0x40
42 #define         INTEL_RNG_ENABLED               0x01
43 #define INTEL_RNG_STATUS                        1
44 #define         INTEL_RNG_DATA_PRESENT          0x01
45 #define INTEL_RNG_DATA                          2
46
47 /*
48  * Magic address at which Intel PCI bridges locate the RNG
49  */
50 #define INTEL_RNG_ADDR                          0xFFBC015F
51 #define INTEL_RNG_ADDR_LEN                      3
52
53 /*
54  * LPC bridge PCI config space registers
55  */
56 #define FWH_DEC_EN1_REG_OLD                     0xe3
57 #define FWH_DEC_EN1_REG_NEW                     0xd9 /* high byte of 16-bit register */
58 #define FWH_F8_EN_MASK                          0x80
59
60 #define BIOS_CNTL_REG_OLD                       0x4e
61 #define BIOS_CNTL_REG_NEW                       0xdc
62 #define BIOS_CNTL_WRITE_ENABLE_MASK             0x01
63 #define BIOS_CNTL_LOCK_ENABLE_MASK              0x02
64
65 /*
66  * Magic address at which Intel Firmware Hubs get accessed
67  */
68 #define INTEL_FWH_ADDR                          0xffff0000
69 #define INTEL_FWH_ADDR_LEN                      2
70
71 /*
72  * Intel Firmware Hub command codes (write to any address inside the device)
73  */
74 #define INTEL_FWH_RESET_CMD                     0xff /* aka READ_ARRAY */
75 #define INTEL_FWH_READ_ID_CMD                   0x90
76
77 /*
78  * Intel Firmware Hub Read ID command result addresses
79  */
80 #define INTEL_FWH_MANUFACTURER_CODE_ADDRESS     0x000000
81 #define INTEL_FWH_DEVICE_CODE_ADDRESS           0x000001
82
83 /*
84  * Intel Firmware Hub Read ID command result values
85  */
86 #define INTEL_FWH_MANUFACTURER_CODE             0x89
87 #define INTEL_FWH_DEVICE_CODE_8M                0xac
88 #define INTEL_FWH_DEVICE_CODE_4M                0xad
89
90 /*
91  * Data for PCI driver interface
92  *
93  * This data only exists for exporting the supported
94  * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
95  * register a pci_driver, because someone else might one day
96  * want to register another driver on the same PCI id.
97  */
98 static const struct pci_device_id pci_tbl[] = {
99 /* AA
100         { PCI_DEVICE(0x8086, 0x2418) }, */
101         { PCI_DEVICE(0x8086, 0x2410) }, /* AA */
102 /* AB
103         { PCI_DEVICE(0x8086, 0x2428) }, */
104         { PCI_DEVICE(0x8086, 0x2420) }, /* AB */
105 /* ??
106         { PCI_DEVICE(0x8086, 0x2430) }, */
107 /* BAM, CAM, DBM, FBM, GxM
108         { PCI_DEVICE(0x8086, 0x2448) }, */
109         { PCI_DEVICE(0x8086, 0x244c) }, /* BAM */
110         { PCI_DEVICE(0x8086, 0x248c) }, /* CAM */
111         { PCI_DEVICE(0x8086, 0x24cc) }, /* DBM */
112         { PCI_DEVICE(0x8086, 0x2641) }, /* FBM */
113         { PCI_DEVICE(0x8086, 0x27b9) }, /* GxM */
114         { PCI_DEVICE(0x8086, 0x27bd) }, /* GxM DH */
115 /* BA, CA, DB, Ex, 6300, Fx, 631x/632x, Gx
116         { PCI_DEVICE(0x8086, 0x244e) }, */
117         { PCI_DEVICE(0x8086, 0x2440) }, /* BA */
118         { PCI_DEVICE(0x8086, 0x2480) }, /* CA */
119         { PCI_DEVICE(0x8086, 0x24c0) }, /* DB */
120         { PCI_DEVICE(0x8086, 0x24d0) }, /* Ex */
121         { PCI_DEVICE(0x8086, 0x25a1) }, /* 6300 */
122         { PCI_DEVICE(0x8086, 0x2640) }, /* Fx */
123         { PCI_DEVICE(0x8086, 0x2670) }, /* 631x/632x */
124         { PCI_DEVICE(0x8086, 0x2671) }, /* 631x/632x */
125         { PCI_DEVICE(0x8086, 0x2672) }, /* 631x/632x */
126         { PCI_DEVICE(0x8086, 0x2673) }, /* 631x/632x */
127         { PCI_DEVICE(0x8086, 0x2674) }, /* 631x/632x */
128         { PCI_DEVICE(0x8086, 0x2675) }, /* 631x/632x */
129         { PCI_DEVICE(0x8086, 0x2676) }, /* 631x/632x */
130         { PCI_DEVICE(0x8086, 0x2677) }, /* 631x/632x */
131         { PCI_DEVICE(0x8086, 0x2678) }, /* 631x/632x */
132         { PCI_DEVICE(0x8086, 0x2679) }, /* 631x/632x */
133         { PCI_DEVICE(0x8086, 0x267a) }, /* 631x/632x */
134         { PCI_DEVICE(0x8086, 0x267b) }, /* 631x/632x */
135         { PCI_DEVICE(0x8086, 0x267c) }, /* 631x/632x */
136         { PCI_DEVICE(0x8086, 0x267d) }, /* 631x/632x */
137         { PCI_DEVICE(0x8086, 0x267e) }, /* 631x/632x */
138         { PCI_DEVICE(0x8086, 0x267f) }, /* 631x/632x */
139         { PCI_DEVICE(0x8086, 0x27b8) }, /* Gx */
140 /* E
141         { PCI_DEVICE(0x8086, 0x245e) }, */
142         { PCI_DEVICE(0x8086, 0x2450) }, /* E  */
143         { 0, }, /* terminate list */
144 };
145 MODULE_DEVICE_TABLE(pci, pci_tbl);
146
147 static __initdata int no_fwh_detect;
148 module_param(no_fwh_detect, int, 0);
149 MODULE_PARM_DESC(no_fwh_detect, "Skip FWH detection:\n"
150                                 " positive value - skip if FWH space locked read-only\n"
151                                 " negative value - skip always");
152
153 static inline u8 hwstatus_get(void __iomem *mem)
154 {
155         return readb(mem + INTEL_RNG_HW_STATUS);
156 }
157
158 static inline u8 hwstatus_set(void __iomem *mem,
159                               u8 hw_status)
160 {
161         writeb(hw_status, mem + INTEL_RNG_HW_STATUS);
162         return hwstatus_get(mem);
163 }
164
165 static int intel_rng_data_present(struct hwrng *rng)
166 {
167         void __iomem *mem = (void __iomem *)rng->priv;
168
169         return !!(readb(mem + INTEL_RNG_STATUS) & INTEL_RNG_DATA_PRESENT);
170 }
171
172 static int intel_rng_data_read(struct hwrng *rng, u32 *data)
173 {
174         void __iomem *mem = (void __iomem *)rng->priv;
175
176         *data = readb(mem + INTEL_RNG_DATA);
177
178         return 1;
179 }
180
181 static int intel_rng_init(struct hwrng *rng)
182 {
183         void __iomem *mem = (void __iomem *)rng->priv;
184         u8 hw_status;
185         int err = -EIO;
186
187         hw_status = hwstatus_get(mem);
188         /* turn RNG h/w on, if it's off */
189         if ((hw_status & INTEL_RNG_ENABLED) == 0)
190                 hw_status = hwstatus_set(mem, hw_status | INTEL_RNG_ENABLED);
191         if ((hw_status & INTEL_RNG_ENABLED) == 0) {
192                 printk(KERN_ERR PFX "cannot enable RNG, aborting\n");
193                 goto out;
194         }
195         err = 0;
196 out:
197         return err;
198 }
199
200 static void intel_rng_cleanup(struct hwrng *rng)
201 {
202         void __iomem *mem = (void __iomem *)rng->priv;
203         u8 hw_status;
204
205         hw_status = hwstatus_get(mem);
206         if (hw_status & INTEL_RNG_ENABLED)
207                 hwstatus_set(mem, hw_status & ~INTEL_RNG_ENABLED);
208         else
209                 printk(KERN_WARNING PFX "unusual: RNG already disabled\n");
210 }
211
212
213 static struct hwrng intel_rng = {
214         .name           = "intel",
215         .init           = intel_rng_init,
216         .cleanup        = intel_rng_cleanup,
217         .data_present   = intel_rng_data_present,
218         .data_read      = intel_rng_data_read,
219 };
220
221 struct intel_rng_hw {
222         struct pci_dev *dev;
223         void __iomem *mem;
224         u8 bios_cntl_off;
225         u8 bios_cntl_val;
226         u8 fwh_dec_en1_off;
227         u8 fwh_dec_en1_val;
228 };
229
230 static int __init intel_rng_hw_init(void *_intel_rng_hw)
231 {
232         struct intel_rng_hw *intel_rng_hw = _intel_rng_hw;
233         u8 mfc, dvc;
234
235         /* interrupts disabled in stop_machine_run call */
236
237         if (!(intel_rng_hw->fwh_dec_en1_val & FWH_F8_EN_MASK))
238                 pci_write_config_byte(intel_rng_hw->dev,
239                                       intel_rng_hw->fwh_dec_en1_off,
240                                       intel_rng_hw->fwh_dec_en1_val |
241                                       FWH_F8_EN_MASK);
242         if (!(intel_rng_hw->bios_cntl_val & BIOS_CNTL_WRITE_ENABLE_MASK))
243                 pci_write_config_byte(intel_rng_hw->dev,
244                                       intel_rng_hw->bios_cntl_off,
245                                       intel_rng_hw->bios_cntl_val |
246                                       BIOS_CNTL_WRITE_ENABLE_MASK);
247
248         writeb(INTEL_FWH_RESET_CMD, intel_rng_hw->mem);
249         writeb(INTEL_FWH_READ_ID_CMD, intel_rng_hw->mem);
250         mfc = readb(intel_rng_hw->mem + INTEL_FWH_MANUFACTURER_CODE_ADDRESS);
251         dvc = readb(intel_rng_hw->mem + INTEL_FWH_DEVICE_CODE_ADDRESS);
252         writeb(INTEL_FWH_RESET_CMD, intel_rng_hw->mem);
253
254         if (!(intel_rng_hw->bios_cntl_val &
255               (BIOS_CNTL_LOCK_ENABLE_MASK|BIOS_CNTL_WRITE_ENABLE_MASK)))
256                 pci_write_config_byte(intel_rng_hw->dev,
257                                       intel_rng_hw->bios_cntl_off,
258                                       intel_rng_hw->bios_cntl_val);
259         if (!(intel_rng_hw->fwh_dec_en1_val & FWH_F8_EN_MASK))
260                 pci_write_config_byte(intel_rng_hw->dev,
261                                       intel_rng_hw->fwh_dec_en1_off,
262                                       intel_rng_hw->fwh_dec_en1_val);
263
264         if (mfc != INTEL_FWH_MANUFACTURER_CODE ||
265             (dvc != INTEL_FWH_DEVICE_CODE_8M &&
266              dvc != INTEL_FWH_DEVICE_CODE_4M)) {
267                 printk(KERN_ERR PFX "FWH not detected\n");
268                 return -ENODEV;
269         }
270
271         return 0;
272 }
273
274 static int __init intel_init_hw_struct(struct intel_rng_hw *intel_rng_hw,
275                                         struct pci_dev *dev)
276 {
277         intel_rng_hw->bios_cntl_val = 0xff;
278         intel_rng_hw->fwh_dec_en1_val = 0xff;
279         intel_rng_hw->dev = dev;
280
281         /* Check for Intel 82802 */
282         if (dev->device < 0x2640) {
283                 intel_rng_hw->fwh_dec_en1_off = FWH_DEC_EN1_REG_OLD;
284                 intel_rng_hw->bios_cntl_off = BIOS_CNTL_REG_OLD;
285         } else {
286                 intel_rng_hw->fwh_dec_en1_off = FWH_DEC_EN1_REG_NEW;
287                 intel_rng_hw->bios_cntl_off = BIOS_CNTL_REG_NEW;
288         }
289
290         pci_read_config_byte(dev, intel_rng_hw->fwh_dec_en1_off,
291                              &intel_rng_hw->fwh_dec_en1_val);
292         pci_read_config_byte(dev, intel_rng_hw->bios_cntl_off,
293                              &intel_rng_hw->bios_cntl_val);
294
295         if ((intel_rng_hw->bios_cntl_val &
296              (BIOS_CNTL_LOCK_ENABLE_MASK|BIOS_CNTL_WRITE_ENABLE_MASK))
297             == BIOS_CNTL_LOCK_ENABLE_MASK) {
298                 static __initdata /*const*/ char warning[] =
299                         KERN_WARNING PFX "Firmware space is locked read-only. If you can't or\n"
300                         KERN_WARNING PFX "don't want to disable this in firmware setup, and if\n"
301                         KERN_WARNING PFX "you are certain that your system has a functional\n"
302                         KERN_WARNING PFX "RNG, try using the 'no_fwh_detect' option.\n";
303
304                 if (no_fwh_detect)
305                         return -ENODEV;
306                 printk(warning);
307                 return -EBUSY;
308         }
309
310         intel_rng_hw->mem = ioremap_nocache(INTEL_FWH_ADDR, INTEL_FWH_ADDR_LEN);
311         if (intel_rng_hw->mem == NULL)
312                 return -EBUSY;
313
314         return 0;
315 }
316
317
318 static int __init mod_init(void)
319 {
320         int err = -ENODEV;
321         int i;
322         struct pci_dev *dev = NULL;
323         void __iomem *mem = mem;
324         u8 hw_status;
325         struct intel_rng_hw *intel_rng_hw;
326
327         for (i = 0; !dev && pci_tbl[i].vendor; ++i)
328                 dev = pci_get_device(pci_tbl[i].vendor, pci_tbl[i].device,
329                                      NULL);
330
331         if (!dev)
332                 goto out; /* Device not found. */
333
334         if (no_fwh_detect < 0) {
335                 pci_dev_put(dev);
336                 goto fwh_done;
337         }
338
339         intel_rng_hw = kmalloc(sizeof(*intel_rng_hw), GFP_KERNEL);
340         if (!intel_rng_hw) {
341                 pci_dev_put(dev);
342                 goto out;
343         }
344
345         err = intel_init_hw_struct(intel_rng_hw, dev);
346         if (err) {
347                 pci_dev_put(dev);
348                 kfree(intel_rng_hw);
349                 if (err == -ENODEV)
350                         goto fwh_done;
351                 goto out;
352         }
353
354         /*
355          * Since the BIOS code/data is going to disappear from its normal
356          * location with the Read ID command, all activity on the system
357          * must be stopped until the state is back to normal.
358          *
359          * Use stop_machine_run because IPIs can be blocked by disabling
360          * interrupts.
361          */
362         err = stop_machine_run(intel_rng_hw_init, intel_rng_hw, NR_CPUS);
363         pci_dev_put(dev);
364         iounmap(intel_rng_hw->mem);
365         kfree(intel_rng_hw);
366         if (err)
367                 goto out;
368
369 fwh_done:
370         err = -ENOMEM;
371         mem = ioremap(INTEL_RNG_ADDR, INTEL_RNG_ADDR_LEN);
372         if (!mem)
373                 goto out;
374         intel_rng.priv = (unsigned long)mem;
375
376         /* Check for Random Number Generator */
377         err = -ENODEV;
378         hw_status = hwstatus_get(mem);
379         if ((hw_status & INTEL_RNG_PRESENT) == 0) {
380                 iounmap(mem);
381                 goto out;
382         }
383
384         printk(KERN_INFO "Intel 82802 RNG detected\n");
385         err = hwrng_register(&intel_rng);
386         if (err) {
387                 printk(KERN_ERR PFX "RNG registering failed (%d)\n",
388                        err);
389                 iounmap(mem);
390         }
391 out:
392         return err;
393
394 }
395
396 static void __exit mod_exit(void)
397 {
398         void __iomem *mem = (void __iomem *)intel_rng.priv;
399
400         hwrng_unregister(&intel_rng);
401         iounmap(mem);
402 }
403
404 module_init(mod_init);
405 module_exit(mod_exit);
406
407 MODULE_DESCRIPTION("H/W RNG driver for Intel chipsets");
408 MODULE_LICENSE("GPL");