linux/drivers/char/hw_random/n2-drv.c
Sam Ravnborg 3f4528d6e9 sparc64: Fix unsigned long long warnings in drivers.
Fix warnings caused by the unsigned long long usage in sparc
specific drivers.

The drivers were considered sparc specific more or less from the
filename alone.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-06 13:20:38 -08:00

771 lines
18 KiB
C

/* n2-drv.c: Niagara-2 RNG driver.
*
* Copyright (C) 2008 David S. Miller <davem@davemloft.net>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/preempt.h>
#include <linux/hw_random.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <asm/hypervisor.h>
#include "n2rng.h"
#define DRV_MODULE_NAME "n2rng"
#define PFX DRV_MODULE_NAME ": "
#define DRV_MODULE_VERSION "0.1"
#define DRV_MODULE_RELDATE "May 15, 2008"
static char version[] __devinitdata =
DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")\n";
MODULE_AUTHOR("David S. Miller (davem@davemloft.net)");
MODULE_DESCRIPTION("Niagara2 RNG driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_MODULE_VERSION);
/* The Niagara2 RNG provides a 64-bit read-only random number
* register, plus a control register. Access to the RNG is
* virtualized through the hypervisor so that both guests and control
* nodes can access the device.
*
* The entropy source consists of raw entropy sources, each
* constructed from a voltage controlled oscillator whose phase is
* jittered by thermal noise sources.
*
* The oscillator in each of the three raw entropy sources run at
* different frequencies. Normally, all three generator outputs are
* gathered, xored together, and fed into a CRC circuit, the output of
* which is the 64-bit read-only register.
*
* Some time is necessary for all the necessary entropy to build up
* such that a full 64-bits of entropy are available in the register.
* In normal operating mode (RNG_CTL_LFSR is set), the chip implements
* an interlock which blocks register reads until sufficient entropy
* is available.
*
* A control register is provided for adjusting various aspects of RNG
* operation, and to enable diagnostic modes. Each of the three raw
* entropy sources has an enable bit (RNG_CTL_ES{1,2,3}). Also
* provided are fields for controlling the minimum time in cycles
* between read accesses to the register (RNG_CTL_WAIT, this controls
* the interlock described in the previous paragraph).
*
* The standard setting is to have the mode bit (RNG_CTL_LFSR) set,
* all three entropy sources enabled, and the interlock time set
* appropriately.
*
* The CRC polynomial used by the chip is:
*
* P(X) = x64 + x61 + x57 + x56 + x52 + x51 + x50 + x48 + x47 + x46 +
* x43 + x42 + x41 + x39 + x38 + x37 + x35 + x32 + x28 + x25 +
* x22 + x21 + x17 + x15 + x13 + x12 + x11 + x7 + x5 + x + 1
*
* The RNG_CTL_VCO value of each noise cell must be programmed
* seperately. This is why 4 control register values must be provided
* to the hypervisor. During a write, the hypervisor writes them all,
* one at a time, to the actual RNG_CTL register. The first three
* values are used to setup the desired RNG_CTL_VCO for each entropy
* source, for example:
*
* control 0: (1 << RNG_CTL_VCO_SHIFT) | RNG_CTL_ES1
* control 1: (2 << RNG_CTL_VCO_SHIFT) | RNG_CTL_ES2
* control 2: (3 << RNG_CTL_VCO_SHIFT) | RNG_CTL_ES3
*
* And then the fourth value sets the final chip state and enables
* desired.
*/
static int n2rng_hv_err_trans(unsigned long hv_err)
{
switch (hv_err) {
case HV_EOK:
return 0;
case HV_EWOULDBLOCK:
return -EAGAIN;
case HV_ENOACCESS:
return -EPERM;
case HV_EIO:
return -EIO;
case HV_EBUSY:
return -EBUSY;
case HV_EBADALIGN:
case HV_ENORADDR:
return -EFAULT;
default:
return -EINVAL;
}
}
static unsigned long n2rng_generic_read_control_v2(unsigned long ra,
unsigned long unit)
{
unsigned long hv_err, state, ticks, watchdog_delta, watchdog_status;
int block = 0, busy = 0;
while (1) {
hv_err = sun4v_rng_ctl_read_v2(ra, unit, &state,
&ticks,
&watchdog_delta,
&watchdog_status);
if (hv_err == HV_EOK)
break;
if (hv_err == HV_EBUSY) {
if (++busy >= N2RNG_BUSY_LIMIT)
break;
udelay(1);
} else if (hv_err == HV_EWOULDBLOCK) {
if (++block >= N2RNG_BLOCK_LIMIT)
break;
__delay(ticks);
} else
break;
}
return hv_err;
}
/* In multi-socket situations, the hypervisor might need to
* queue up the RNG control register write if it's for a unit
* that is on a cpu socket other than the one we are executing on.
*
* We poll here waiting for a successful read of that control
* register to make sure the write has been actually performed.
*/
static unsigned long n2rng_control_settle_v2(struct n2rng *np, int unit)
{
unsigned long ra = __pa(&np->scratch_control[0]);
return n2rng_generic_read_control_v2(ra, unit);
}
static unsigned long n2rng_write_ctl_one(struct n2rng *np, int unit,
unsigned long state,
unsigned long control_ra,
unsigned long watchdog_timeout,
unsigned long *ticks)
{
unsigned long hv_err;
if (np->hvapi_major == 1) {
hv_err = sun4v_rng_ctl_write_v1(control_ra, state,
watchdog_timeout, ticks);
} else {
hv_err = sun4v_rng_ctl_write_v2(control_ra, state,
watchdog_timeout, unit);
if (hv_err == HV_EOK)
hv_err = n2rng_control_settle_v2(np, unit);
*ticks = N2RNG_ACCUM_CYCLES_DEFAULT;
}
return hv_err;
}
static int n2rng_generic_read_data(unsigned long data_ra)
{
unsigned long ticks, hv_err;
int block = 0, hcheck = 0;
while (1) {
hv_err = sun4v_rng_data_read(data_ra, &ticks);
if (hv_err == HV_EOK)
return 0;
if (hv_err == HV_EWOULDBLOCK) {
if (++block >= N2RNG_BLOCK_LIMIT)
return -EWOULDBLOCK;
__delay(ticks);
} else if (hv_err == HV_ENOACCESS) {
return -EPERM;
} else if (hv_err == HV_EIO) {
if (++hcheck >= N2RNG_HCHECK_LIMIT)
return -EIO;
udelay(10000);
} else
return -ENODEV;
}
}
static unsigned long n2rng_read_diag_data_one(struct n2rng *np,
unsigned long unit,
unsigned long data_ra,
unsigned long data_len,
unsigned long *ticks)
{
unsigned long hv_err;
if (np->hvapi_major == 1) {
hv_err = sun4v_rng_data_read_diag_v1(data_ra, data_len, ticks);
} else {
hv_err = sun4v_rng_data_read_diag_v2(data_ra, data_len,
unit, ticks);
if (!*ticks)
*ticks = N2RNG_ACCUM_CYCLES_DEFAULT;
}
return hv_err;
}
static int n2rng_generic_read_diag_data(struct n2rng *np,
unsigned long unit,
unsigned long data_ra,
unsigned long data_len)
{
unsigned long ticks, hv_err;
int block = 0;
while (1) {
hv_err = n2rng_read_diag_data_one(np, unit,
data_ra, data_len,
&ticks);
if (hv_err == HV_EOK)
return 0;
if (hv_err == HV_EWOULDBLOCK) {
if (++block >= N2RNG_BLOCK_LIMIT)
return -EWOULDBLOCK;
__delay(ticks);
} else if (hv_err == HV_ENOACCESS) {
return -EPERM;
} else if (hv_err == HV_EIO) {
return -EIO;
} else
return -ENODEV;
}
}
static int n2rng_generic_write_control(struct n2rng *np,
unsigned long control_ra,
unsigned long unit,
unsigned long state)
{
unsigned long hv_err, ticks;
int block = 0, busy = 0;
while (1) {
hv_err = n2rng_write_ctl_one(np, unit, state, control_ra,
np->wd_timeo, &ticks);
if (hv_err == HV_EOK)
return 0;
if (hv_err == HV_EWOULDBLOCK) {
if (++block >= N2RNG_BLOCK_LIMIT)
return -EWOULDBLOCK;
__delay(ticks);
} else if (hv_err == HV_EBUSY) {
if (++busy >= N2RNG_BUSY_LIMIT)
return -EBUSY;
udelay(1);
} else
return -ENODEV;
}
}
/* Just try to see if we can successfully access the control register
* of the RNG on the domain on which we are currently executing.
*/
static int n2rng_try_read_ctl(struct n2rng *np)
{
unsigned long hv_err;
unsigned long x;
if (np->hvapi_major == 1) {
hv_err = sun4v_rng_get_diag_ctl();
} else {
/* We purposefully give invalid arguments, HV_NOACCESS
* is higher priority than the errors we'd get from
* these other cases, and that's the error we are
* truly interested in.
*/
hv_err = sun4v_rng_ctl_read_v2(0UL, ~0UL, &x, &x, &x, &x);
switch (hv_err) {
case HV_EWOULDBLOCK:
case HV_ENOACCESS:
break;
default:
hv_err = HV_EOK;
break;
}
}
return n2rng_hv_err_trans(hv_err);
}
#define CONTROL_DEFAULT_BASE \
((2 << RNG_CTL_ASEL_SHIFT) | \
(N2RNG_ACCUM_CYCLES_DEFAULT << RNG_CTL_WAIT_SHIFT) | \
RNG_CTL_LFSR)
#define CONTROL_DEFAULT_0 \
(CONTROL_DEFAULT_BASE | \
(1 << RNG_CTL_VCO_SHIFT) | \
RNG_CTL_ES1)
#define CONTROL_DEFAULT_1 \
(CONTROL_DEFAULT_BASE | \
(2 << RNG_CTL_VCO_SHIFT) | \
RNG_CTL_ES2)
#define CONTROL_DEFAULT_2 \
(CONTROL_DEFAULT_BASE | \
(3 << RNG_CTL_VCO_SHIFT) | \
RNG_CTL_ES3)
#define CONTROL_DEFAULT_3 \
(CONTROL_DEFAULT_BASE | \
RNG_CTL_ES1 | RNG_CTL_ES2 | RNG_CTL_ES3)
static void n2rng_control_swstate_init(struct n2rng *np)
{
int i;
np->flags |= N2RNG_FLAG_CONTROL;
np->health_check_sec = N2RNG_HEALTH_CHECK_SEC_DEFAULT;
np->accum_cycles = N2RNG_ACCUM_CYCLES_DEFAULT;
np->wd_timeo = N2RNG_WD_TIMEO_DEFAULT;
for (i = 0; i < np->num_units; i++) {
struct n2rng_unit *up = &np->units[i];
up->control[0] = CONTROL_DEFAULT_0;
up->control[1] = CONTROL_DEFAULT_1;
up->control[2] = CONTROL_DEFAULT_2;
up->control[3] = CONTROL_DEFAULT_3;
}
np->hv_state = HV_RNG_STATE_UNCONFIGURED;
}
static int n2rng_grab_diag_control(struct n2rng *np)
{
int i, busy_count, err = -ENODEV;
busy_count = 0;
for (i = 0; i < 100; i++) {
err = n2rng_try_read_ctl(np);
if (err != -EAGAIN)
break;
if (++busy_count > 100) {
dev_err(&np->op->dev,
"Grab diag control timeout.\n");
return -ENODEV;
}
udelay(1);
}
return err;
}
static int n2rng_init_control(struct n2rng *np)
{
int err = n2rng_grab_diag_control(np);
/* Not in the control domain, that's OK we are only a consumer
* of the RNG data, we don't setup and program it.
*/
if (err == -EPERM)
return 0;
if (err)
return err;
n2rng_control_swstate_init(np);
return 0;
}
static int n2rng_data_read(struct hwrng *rng, u32 *data)
{
struct n2rng *np = (struct n2rng *) rng->priv;
unsigned long ra = __pa(&np->test_data);
int len;
if (!(np->flags & N2RNG_FLAG_READY)) {
len = 0;
} else if (np->flags & N2RNG_FLAG_BUFFER_VALID) {
np->flags &= ~N2RNG_FLAG_BUFFER_VALID;
*data = np->buffer;
len = 4;
} else {
int err = n2rng_generic_read_data(ra);
if (!err) {
np->buffer = np->test_data >> 32;
*data = np->test_data & 0xffffffff;
len = 4;
} else {
dev_err(&np->op->dev, "RNG error, restesting\n");
np->flags &= ~N2RNG_FLAG_READY;
if (!(np->flags & N2RNG_FLAG_SHUTDOWN))
schedule_delayed_work(&np->work, 0);
len = 0;
}
}
return len;
}
/* On a guest node, just make sure we can read random data properly.
* If a control node reboots or reloads it's n2rng driver, this won't
* work during that time. So we have to keep probing until the device
* becomes usable.
*/
static int n2rng_guest_check(struct n2rng *np)
{
unsigned long ra = __pa(&np->test_data);
return n2rng_generic_read_data(ra);
}
static int n2rng_entropy_diag_read(struct n2rng *np, unsigned long unit,
u64 *pre_control, u64 pre_state,
u64 *buffer, unsigned long buf_len,
u64 *post_control, u64 post_state)
{
unsigned long post_ctl_ra = __pa(post_control);
unsigned long pre_ctl_ra = __pa(pre_control);
unsigned long buffer_ra = __pa(buffer);
int err;
err = n2rng_generic_write_control(np, pre_ctl_ra, unit, pre_state);
if (err)
return err;
err = n2rng_generic_read_diag_data(np, unit,
buffer_ra, buf_len);
(void) n2rng_generic_write_control(np, post_ctl_ra, unit,
post_state);
return err;
}
static u64 advance_polynomial(u64 poly, u64 val, int count)
{
int i;
for (i = 0; i < count; i++) {
int highbit_set = ((s64)val < 0);
val <<= 1;
if (highbit_set)
val ^= poly;
}
return val;
}
static int n2rng_test_buffer_find(struct n2rng *np, u64 val)
{
int i, count = 0;
/* Purposefully skip over the first word. */
for (i = 1; i < SELFTEST_BUFFER_WORDS; i++) {
if (np->test_buffer[i] == val)
count++;
}
return count;
}
static void n2rng_dump_test_buffer(struct n2rng *np)
{
int i;
for (i = 0; i < SELFTEST_BUFFER_WORDS; i++)
dev_err(&np->op->dev, "Test buffer slot %d [0x%016llx]\n",
i, np->test_buffer[i]);
}
static int n2rng_check_selftest_buffer(struct n2rng *np, unsigned long unit)
{
u64 val = SELFTEST_VAL;
int err, matches, limit;
matches = 0;
for (limit = 0; limit < SELFTEST_LOOPS_MAX; limit++) {
matches += n2rng_test_buffer_find(np, val);
if (matches >= SELFTEST_MATCH_GOAL)
break;
val = advance_polynomial(SELFTEST_POLY, val, 1);
}
err = 0;
if (limit >= SELFTEST_LOOPS_MAX) {
err = -ENODEV;
dev_err(&np->op->dev, "Selftest failed on unit %lu\n", unit);
n2rng_dump_test_buffer(np);
} else
dev_info(&np->op->dev, "Selftest passed on unit %lu\n", unit);
return err;
}
static int n2rng_control_selftest(struct n2rng *np, unsigned long unit)
{
int err;
np->test_control[0] = (0x2 << RNG_CTL_ASEL_SHIFT);
np->test_control[1] = (0x2 << RNG_CTL_ASEL_SHIFT);
np->test_control[2] = (0x2 << RNG_CTL_ASEL_SHIFT);
np->test_control[3] = ((0x2 << RNG_CTL_ASEL_SHIFT) |
RNG_CTL_LFSR |
((SELFTEST_TICKS - 2) << RNG_CTL_WAIT_SHIFT));
err = n2rng_entropy_diag_read(np, unit, np->test_control,
HV_RNG_STATE_HEALTHCHECK,
np->test_buffer,
sizeof(np->test_buffer),
&np->units[unit].control[0],
np->hv_state);
if (err)
return err;
return n2rng_check_selftest_buffer(np, unit);
}
static int n2rng_control_check(struct n2rng *np)
{
int i;
for (i = 0; i < np->num_units; i++) {
int err = n2rng_control_selftest(np, i);
if (err)
return err;
}
return 0;
}
/* The sanity checks passed, install the final configuration into the
* chip, it's ready to use.
*/
static int n2rng_control_configure_units(struct n2rng *np)
{
int unit, err;
err = 0;
for (unit = 0; unit < np->num_units; unit++) {
struct n2rng_unit *up = &np->units[unit];
unsigned long ctl_ra = __pa(&up->control[0]);
int esrc;
u64 base;
base = ((np->accum_cycles << RNG_CTL_WAIT_SHIFT) |
(2 << RNG_CTL_ASEL_SHIFT) |
RNG_CTL_LFSR);
/* XXX This isn't the best. We should fetch a bunch
* XXX of words using each entropy source combined XXX
* with each VCO setting, and see which combinations
* XXX give the best random data.
*/
for (esrc = 0; esrc < 3; esrc++)
up->control[esrc] = base |
(esrc << RNG_CTL_VCO_SHIFT) |
(RNG_CTL_ES1 << esrc);
up->control[3] = base |
(RNG_CTL_ES1 | RNG_CTL_ES2 | RNG_CTL_ES3);
err = n2rng_generic_write_control(np, ctl_ra, unit,
HV_RNG_STATE_CONFIGURED);
if (err)
break;
}
return err;
}
static void n2rng_work(struct work_struct *work)
{
struct n2rng *np = container_of(work, struct n2rng, work.work);
int err = 0;
if (!(np->flags & N2RNG_FLAG_CONTROL)) {
err = n2rng_guest_check(np);
} else {
preempt_disable();
err = n2rng_control_check(np);
preempt_enable();
if (!err)
err = n2rng_control_configure_units(np);
}
if (!err) {
np->flags |= N2RNG_FLAG_READY;
dev_info(&np->op->dev, "RNG ready\n");
}
if (err && !(np->flags & N2RNG_FLAG_SHUTDOWN))
schedule_delayed_work(&np->work, HZ * 2);
}
static void __devinit n2rng_driver_version(void)
{
static int n2rng_version_printed;
if (n2rng_version_printed++ == 0)
pr_info("%s", version);
}
static int __devinit n2rng_probe(struct of_device *op,
const struct of_device_id *match)
{
int victoria_falls = (match->data != NULL);
int err = -ENOMEM;
struct n2rng *np;
n2rng_driver_version();
np = kzalloc(sizeof(*np), GFP_KERNEL);
if (!np)
goto out;
np->op = op;
INIT_DELAYED_WORK(&np->work, n2rng_work);
if (victoria_falls)
np->flags |= N2RNG_FLAG_VF;
err = -ENODEV;
np->hvapi_major = 2;
if (sun4v_hvapi_register(HV_GRP_RNG,
np->hvapi_major,
&np->hvapi_minor)) {
np->hvapi_major = 1;
if (sun4v_hvapi_register(HV_GRP_RNG,
np->hvapi_major,
&np->hvapi_minor)) {
dev_err(&op->dev, "Cannot register suitable "
"HVAPI version.\n");
goto out_free;
}
}
if (np->flags & N2RNG_FLAG_VF) {
if (np->hvapi_major < 2) {
dev_err(&op->dev, "VF RNG requires HVAPI major "
"version 2 or later, got %lu\n",
np->hvapi_major);
goto out_hvapi_unregister;
}
np->num_units = of_getintprop_default(op->node,
"rng-#units", 0);
if (!np->num_units) {
dev_err(&op->dev, "VF RNG lacks rng-#units property\n");
goto out_hvapi_unregister;
}
} else
np->num_units = 1;
dev_info(&op->dev, "Registered RNG HVAPI major %lu minor %lu\n",
np->hvapi_major, np->hvapi_minor);
np->units = kzalloc(sizeof(struct n2rng_unit) * np->num_units,
GFP_KERNEL);
err = -ENOMEM;
if (!np->units)
goto out_hvapi_unregister;
err = n2rng_init_control(np);
if (err)
goto out_free_units;
dev_info(&op->dev, "Found %s RNG, units: %d\n",
((np->flags & N2RNG_FLAG_VF) ?
"Victoria Falls" : "Niagara2"),
np->num_units);
np->hwrng.name = "n2rng";
np->hwrng.data_read = n2rng_data_read;
np->hwrng.priv = (unsigned long) np;
err = hwrng_register(&np->hwrng);
if (err)
goto out_free_units;
dev_set_drvdata(&op->dev, np);
schedule_delayed_work(&np->work, 0);
return 0;
out_free_units:
kfree(np->units);
np->units = NULL;
out_hvapi_unregister:
sun4v_hvapi_unregister(HV_GRP_RNG);
out_free:
kfree(np);
out:
return err;
}
static int __devexit n2rng_remove(struct of_device *op)
{
struct n2rng *np = dev_get_drvdata(&op->dev);
np->flags |= N2RNG_FLAG_SHUTDOWN;
cancel_delayed_work_sync(&np->work);
hwrng_unregister(&np->hwrng);
sun4v_hvapi_unregister(HV_GRP_RNG);
kfree(np->units);
np->units = NULL;
kfree(np);
dev_set_drvdata(&op->dev, NULL);
return 0;
}
static const struct of_device_id n2rng_match[] = {
{
.name = "random-number-generator",
.compatible = "SUNW,n2-rng",
},
{
.name = "random-number-generator",
.compatible = "SUNW,vf-rng",
.data = (void *) 1,
},
{},
};
MODULE_DEVICE_TABLE(of, n2rng_match);
static struct of_platform_driver n2rng_driver = {
.name = "n2rng",
.match_table = n2rng_match,
.probe = n2rng_probe,
.remove = __devexit_p(n2rng_remove),
};
static int __init n2rng_init(void)
{
return of_register_driver(&n2rng_driver, &of_bus_type);
}
static void __exit n2rng_exit(void)
{
of_unregister_driver(&n2rng_driver);
}
module_init(n2rng_init);
module_exit(n2rng_exit);