/*
* Loopback bridge driver for the Greybus loopback module.
*
* Copyright 2014 Google Inc.
* Copyright 2014 Linaro Ltd.
*
* Released under the GPLv2 only.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/random.h>
#include <linux/sizes.h>
#include <asm/div64.h>
#include "greybus.h"
struct gb_loopback_stats {
u64 min;
u64 max;
u64 avg;
u64 sum;
u64 count;
};
struct gb_loopback {
struct gb_connection *connection;
u8 version_major;
u8 version_minor;
struct task_struct *task;
int type;
u32 size;
u32 iteration_max;
u32 iteration_count;
size_t size_max;
int ms_wait;
struct gb_loopback_stats latency;
struct gb_loopback_stats throughput;
struct gb_loopback_stats frequency;
struct timeval ts;
struct timeval te;
u64 elapsed_nsecs;
u32 error;
};
#define GB_LOOPBACK_MS_WAIT_MAX 1000
/* Define get_version() routine */
define_get_version(gb_loopback, LOOPBACK);
/* interface sysfs attributes */
#define gb_loopback_ro_attr(field, type) \
static ssize_t field##_show(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct gb_connection *connection = to_gb_connection(dev); \
struct gb_loopback *gb = \
(struct gb_loopback *)connection->private; \
return sprintf(buf, "%"#type"\n", gb->field); \
} \
static DEVICE_ATTR_RO(field)
#define gb_loopback_ro_stats_attr(name, field, type) \
static ssize_t name##_##field##_show(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct gb_connection *connection = to_gb_connection(dev); \
struct gb_loopback *gb = \
(struct gb_loopback *)connection->private; \
return sprintf(buf, "%"#type"\n", gb->name.field); \
} \
static DEVICE_ATTR_RO(name##_##field)
#define gb_loopback_stats_attrs(field) \
gb_loopback_ro_stats_attr(field, min, llu); \
gb_loopback_ro_stats_attr(field, max, llu); \
gb_loopback_ro_stats_attr(field, avg, llu);
#define gb_loopback_attr(field, type) \
static ssize_t field##_show(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct gb_connection *connection = to_gb_connection(dev); \
struct gb_loopback *gb = \
(struct gb_loopback *)connection->private; \
return sprintf(buf, "%"#type"\n", gb->field); \
} \
static ssize_t field##_store(struct device *dev, \
struct device_attribute *attr, \
const char *buf, \
size_t len) \
{ \
int ret; \
struct gb_connection *connection = to_gb_connection(dev); \
struct gb_loopback *gb = \
(struct gb_loopback *)connection->private; \
ret = sscanf(buf, "%"#type, &gb->field); \
if (ret != 1) \
return -EINVAL; \
gb_loopback_check_attr(gb); \
return len; \
} \
static DEVICE_ATTR_RW(field)
static void gb_loopback_reset_stats(struct gb_loopback *gb);
static void gb_loopback_check_attr(struct gb_loopback *gb)
{
switch (gb->type) {
case GB_LOOPBACK_TYPE_PING:
case GB_LOOPBACK_TYPE_TRANSFER:
case GB_LOOPBACK_TYPE_SINK:
break;
default:
gb->type = 0;
break;
}
if (gb->ms_wait > GB_LOOPBACK_MS_WAIT_MAX)
gb->ms_wait = GB_LOOPBACK_MS_WAIT_MAX;
if (gb->size > gb->size_max)
gb->size = gb->size_max;
gb->error = 0;
gb->iteration_count = 0;
gb_loopback_reset_stats(gb);
}
/* Time to send and receive one message */
gb_loopback_stats_attrs(latency);
/* Number of packet sent per second on this cport */
gb_loopback_stats_attrs(frequency);
/* Quantity of data sent and received on this cport */
gb_loopback_stats_attrs(throughput);
/* Number of errors encountered during loop */
gb_loopback_ro_attr(error, d);
/* The current index of the for (i = 0; i < iteration_max; i++) loop */
gb_loopback_ro_attr(iteration_count, u);
/* TODO iteration_count might be better with the KOBJ_CHANGE event */
/*
* Type of loopback message to send based on protocol type definitions
* 0 => Don't send message
* 2 => Send ping message continuously (message without payload)
* 3 => Send transer message continuously (message with payload,
* payload returned in response)
* 4 => Send a sink message (message with payload, no payload in response)
*/
gb_loopback_attr(type, d);
/* Size of transfer message payload: 0-4096 bytes */
gb_loopback_attr(size, u);
/* Time to wait between two messages: 0-1000 ms */
gb_loopback_attr(ms_wait, d);
/* Maximum iterations for a given operation: 1-(2^32-1), 0 implies infinite */
gb_loopback_attr(iteration_max, u);
#define dev_stats_attrs(name) \
&dev_attr_##name##_min.attr, \
&dev_attr_##name##_max.attr, \
&dev_attr_##name##_avg.attr
static struct attribute *loopback_attrs[] = {
dev_stats_attrs(latency),
dev_stats_attrs(frequency),
dev_stats_attrs(throughput),
&dev_attr_type.attr,
&dev_attr_size.attr,
&dev_attr_ms_wait.attr,
&dev_attr_iteration_count.attr,
&dev_attr_iteration_max.attr,
&dev_attr_error.attr,
NULL,
};
ATTRIBUTE_GROUPS(loopback);
static int gb_loopback_sink(struct gb_loopback *gb,
struct timeval *tping, u32 len)
{
struct timeval ts, te;
u64 elapsed_nsecs;
struct gb_loopback_transfer_request *request;
int retval;
request = kmalloc(len + sizeof(*request), GFP_KERNEL);
if (!request)
return -ENOMEM;
request->len = cpu_to_le32(len);
do_gettimeofday(&ts);
retval = gb_operation_sync(gb->connection, GB_LOOPBACK_TYPE_SINK,
request, len + sizeof(*request), NULL, 0);
do_gettimeofday(&te);
elapsed_nsecs = timeval_to_ns(&te) - timeval_to_ns(&ts);
*tping = ns_to_timeval(elapsed_nsecs);
kfree(request);
return retval;
}
static int gb_loopback_transfer(struct gb_loopback *gb,
struct timeval *tping, u32 len)
{
struct timeval ts, te;
u64 elapsed_nsecs;
struct gb_loopback_transfer_request *request;
struct gb_loopback_transfer_response *response;
int retval;
request = kmalloc(len + sizeof(*request), GFP_KERNEL);
if (!request)
return -ENOMEM;
response = kmalloc(len + sizeof(*response), GFP_KERNEL);
if (!response) {
kfree(request);
return -ENOMEM;
}
request->len = cpu_to_le32(len);
do_gettimeofday(&ts);
retval = gb_operation_sync(gb->connection, GB_LOOPBACK_TYPE_TRANSFER,
request, len + sizeof(*request),
response, len + sizeof(*response));
do_gettimeofday(&te);
elapsed_nsecs = timeval_to_ns(&te) - timeval_to_ns(&ts);
*tping = ns_to_timeval(elapsed_nsecs);
if (retval)
goto gb_error;
if (memcmp(request->data, response->data, len))
retval = -EREMOTEIO;
gb_error:
kfree(request);
kfree(response);
return retval;
}
static int gb_loopback_ping(struct gb_loopback *gb, struct timeval *tping)
{
struct timeval ts, te;
u64 elapsed_nsecs;
int retval;
do_gettimeofday(&ts);
retval = gb_operation_sync(gb->connection, GB_LOOPBACK_TYPE_PING,
NULL, 0, NULL, 0);
do_gettimeofday(&te);
elapsed_nsecs = timeval_to_ns(&te) - timeval_to_ns(&ts);
*tping = ns_to_timeval(elapsed_nsecs);
return retval;
}
static int gb_loopback_request_recv(u8 type, struct gb_operation *operation)
{
struct gb_connection *connection = operation->connection;
struct gb_loopback *gb = connection->private;
struct gb_loopback_transfer_request *request;
struct gb_loopback_transfer_response *response;
size_t len;
/* By convention, the AP initiates the version operation */
switch (type) {
case GB_LOOPBACK_TYPE_PROTOCOL_VERSION:
dev_err(&connection->dev,
"module-initiated version operation\n");
return -EINVAL;
case GB_LOOPBACK_TYPE_PING:
case GB_LOOPBACK_TYPE_SINK:
return 0;
case GB_LOOPBACK_TYPE_TRANSFER:
if (operation->request->payload_size < sizeof(*request)) {
dev_err(&connection->dev,
"transfer request too small (%zu < %zu)\n",
operation->request->payload_size,
sizeof(*request));
return -EINVAL; /* -EMSGSIZE */
}
request = operation->request->payload;
len = le32_to_cpu(request->len);
if (len > gb->size_max) {
dev_err(&connection->dev,
"transfer request too large (%zu > %zu)\n",
len, gb->size_max);
return -EINVAL;
}
if (len) {
if (!gb_operation_response_alloc(operation, len,
GFP_KERNEL)) {
dev_err(&connection->dev,
"error allocating response\n");
return -ENOMEM;
}
response = operation->response->payload;
memcpy(response->data, request->data, len);
}
return 0;
default:
dev_err(&connection->dev,
"unsupported request: %hhu\n", type);
return -EINVAL;
}
}
static void gb_loopback_reset_stats(struct gb_loopback *gb)
{
struct gb_loopback_stats reset = {
.min = 0xffffffff,
};
memcpy(&gb->latency, &reset, sizeof(struct gb_loopback_stats));
memcpy(&gb->throughput, &reset, sizeof(struct gb_loopback_stats));
memcpy(&gb->frequency, &reset, sizeof(struct gb_loopback_stats));
memset(&gb->ts, 0, sizeof(struct timeval));
}
static void gb_loopback_update_stats(struct gb_loopback_stats *stats, u64 val)
{
if (stats->min > val)
stats->min = val;
if (stats->max < val)
stats->max = val;
stats->sum += val;
stats->count++;
stats->avg = stats->sum;
do_div(stats->avg, stats->count);
}
static void gb_loopback_frequency_update(struct gb_loopback *gb, u32 latency)
{
u32 freq = USEC_PER_SEC;
do_div(freq, latency);
gb_loopback_update_stats(&gb->frequency, freq);
}
static void gb_loopback_throughput_update(struct gb_loopback *gb, u32 latency)
{
u32 throughput;
u32 aggregate_size = sizeof(struct gb_operation_msg_hdr) * 2;
switch (gb->type) {
case GB_LOOPBACK_TYPE_PING:
break;
case GB_LOOPBACK_TYPE_SINK:
aggregate_size += sizeof(struct gb_loopback_transfer_request) +
gb->size;
break;
case GB_LOOPBACK_TYPE_TRANSFER:
aggregate_size += sizeof(struct gb_loopback_transfer_request) +
sizeof(struct gb_loopback_transfer_response) +
gb->size * 2;
break;
default:
return;
}
/* Calculate bytes per second */
throughput = USEC_PER_SEC;
do_div(throughput, latency);
throughput *= aggregate_size;
gb_loopback_update_stats(&gb->throughput, throughput);
}
static void gb_loopback_calculate_stats(struct gb_loopback *gb,
struct timeval *tlat)
{
u32 lat;
u64 tmp;
/* Express latency in terms of microseconds */
tmp = gb->elapsed_nsecs;
do_div(tmp, NSEC_PER_USEC);
lat = tmp;
/* Log latency stastic */
gb_loopback_update_stats(&gb->latency, lat);
/* Log throughput and frequency using latency as benchmark */
gb_loopback_throughput_update(gb, lat);
gb_loopback_frequency_update(gb, lat);
}
static int gb_loopback_fn(void *data)
{
int error = 0;
struct timeval tlat = {0, 0};
struct gb_loopback *gb = (struct gb_loopback *)data;
while (!kthread_should_stop()) {
if (!gb->type) {
msleep(1000);
continue;
}
if (gb->iteration_max) {
if (gb->iteration_count < gb->iteration_max) {
gb->iteration_count++;
} else {
gb->type = 0;
continue;
}
}
if (gb->ts.tv_usec == 0 && gb->ts.tv_sec == 0)
do_gettimeofday(&gb->ts);
if (gb->type == GB_LOOPBACK_TYPE_PING)
error = gb_loopback_ping(gb, &tlat);
else if (gb->type == GB_LOOPBACK_TYPE_TRANSFER)
error = gb_loopback_transfer(gb, &tlat, gb->size);
else if (gb->type == GB_LOOPBACK_TYPE_SINK)
error = gb_loopback_sink(gb, &tlat, gb->size);
if (error)
gb->error++;
do_gettimeofday(&gb->te);
gb->elapsed_nsecs = timeval_to_ns(&gb->te) -
timeval_to_ns(&gb->ts);
gb_loopback_calculate_stats(gb, &tlat);
gb->ts = gb->te;
if (gb->ms_wait)
msleep(gb->ms_wait);
}
return 0;
}
static int gb_loopback_connection_init(struct gb_connection *connection)
{
struct gb_loopback *gb;
int retval;
gb = kzalloc(sizeof(*gb), GFP_KERNEL);
if (!gb)
return -ENOMEM;
gb->connection = connection;
connection->private = gb;
retval = sysfs_create_groups(&connection->dev.kobj, loopback_groups);
if (retval)
goto out_free;
/* Check the version */
retval = get_version(gb);
if (retval)
goto out_get_ver;
/* Calculate maximum payload */
gb->size_max = gb_operation_get_payload_size_max(connection);
if (gb->size_max <= sizeof(struct gb_loopback_transfer_request)) {
retval = -EINVAL;
goto out_get_ver;
}
gb->size_max -= sizeof(struct gb_loopback_transfer_request);
gb_loopback_reset_stats(gb);
gb->task = kthread_run(gb_loopback_fn, gb, "gb_loopback");
if (IS_ERR(gb->task)) {
retval = PTR_ERR(gb->task);
goto out_get_ver;
}
return 0;
out_get_ver:
sysfs_remove_groups(&connection->dev.kobj, loopback_groups);
out_free:
kfree(gb);
return retval;
}
static void gb_loopback_connection_exit(struct gb_connection *connection)
{
struct gb_loopback *gb = connection->private;
if (!IS_ERR_OR_NULL(gb->task))
kthread_stop(gb->task);
sysfs_remove_groups(&connection->dev.kobj, loopback_groups);
kfree(gb);
}
static struct gb_protocol loopback_protocol = {
.name = "loopback",
.id = GREYBUS_PROTOCOL_LOOPBACK,
.major = GB_LOOPBACK_VERSION_MAJOR,
.minor = GB_LOOPBACK_VERSION_MINOR,
.connection_init = gb_loopback_connection_init,
.connection_exit = gb_loopback_connection_exit,
.request_recv = gb_loopback_request_recv,
};
gb_protocol_driver(&loopback_protocol);
MODULE_LICENSE("GPL v2");
