linux/drivers/counter/counter.c
William Breathitt Gray 0040a390d2 counter: Introduce the Generic Counter interface
This patch introduces the Generic Counter interface for supporting
counter devices.

In the context of the Generic Counter interface, a counter is defined as
a device that reports one or more "counts" based on the state changes of
one or more "signals" as evaluated by a defined "count function."

Driver callbacks should be provided to communicate with the device: to
read and write various Signals and Counts, and to set and get the
"action mode" and "count function" for various Synapses and Counts
respectively.

To support a counter device, a driver must first allocate the available
Counter Signals via counter_signal structures. These Signals should
be stored as an array and set to the signals array member of an
allocated counter_device structure before the Counter is registered to
the system.

Counter Counts may be allocated via counter_count structures, and
respective Counter Signal associations (Synapses) made via
counter_synapse structures. Associated counter_synapse structures are
stored as an array and set to the the synapses array member of the
respective counter_count structure. These counter_count structures are
set to the counts array member of an allocated counter_device structure
before the Counter is registered to the system.

A counter device is registered to the system by passing the respective
initialized counter_device structure to the counter_register function;
similarly, the counter_unregister function unregisters the respective
Counter. The devm_counter_register and devm_counter_unregister functions
serve as device memory-managed versions of the counter_register and
counter_unregister functions respectively.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-25 21:33:37 +02:00

1568 lines
40 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Generic Counter interface
* Copyright (C) 2018 William Breathitt Gray
*/
#include <linux/counter.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/idr.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/types.h>
const char *const counter_count_direction_str[2] = {
[COUNTER_COUNT_DIRECTION_FORWARD] = "forward",
[COUNTER_COUNT_DIRECTION_BACKWARD] = "backward"
};
EXPORT_SYMBOL_GPL(counter_count_direction_str);
const char *const counter_count_mode_str[4] = {
[COUNTER_COUNT_MODE_NORMAL] = "normal",
[COUNTER_COUNT_MODE_RANGE_LIMIT] = "range limit",
[COUNTER_COUNT_MODE_NON_RECYCLE] = "non-recycle",
[COUNTER_COUNT_MODE_MODULO_N] = "modulo-n"
};
EXPORT_SYMBOL_GPL(counter_count_mode_str);
ssize_t counter_signal_enum_read(struct counter_device *counter,
struct counter_signal *signal, void *priv,
char *buf)
{
const struct counter_signal_enum_ext *const e = priv;
int err;
size_t index;
if (!e->get)
return -EINVAL;
err = e->get(counter, signal, &index);
if (err)
return err;
if (index >= e->num_items)
return -EINVAL;
return sprintf(buf, "%s\n", e->items[index]);
}
EXPORT_SYMBOL_GPL(counter_signal_enum_read);
ssize_t counter_signal_enum_write(struct counter_device *counter,
struct counter_signal *signal, void *priv,
const char *buf, size_t len)
{
const struct counter_signal_enum_ext *const e = priv;
ssize_t index;
int err;
if (!e->set)
return -EINVAL;
index = __sysfs_match_string(e->items, e->num_items, buf);
if (index < 0)
return index;
err = e->set(counter, signal, index);
if (err)
return err;
return len;
}
EXPORT_SYMBOL_GPL(counter_signal_enum_write);
ssize_t counter_signal_enum_available_read(struct counter_device *counter,
struct counter_signal *signal,
void *priv, char *buf)
{
const struct counter_signal_enum_ext *const e = priv;
size_t i;
size_t len = 0;
if (!e->num_items)
return 0;
for (i = 0; i < e->num_items; i++)
len += sprintf(buf + len, "%s\n", e->items[i]);
return len;
}
EXPORT_SYMBOL_GPL(counter_signal_enum_available_read);
ssize_t counter_count_enum_read(struct counter_device *counter,
struct counter_count *count, void *priv,
char *buf)
{
const struct counter_count_enum_ext *const e = priv;
int err;
size_t index;
if (!e->get)
return -EINVAL;
err = e->get(counter, count, &index);
if (err)
return err;
if (index >= e->num_items)
return -EINVAL;
return sprintf(buf, "%s\n", e->items[index]);
}
EXPORT_SYMBOL_GPL(counter_count_enum_read);
ssize_t counter_count_enum_write(struct counter_device *counter,
struct counter_count *count, void *priv,
const char *buf, size_t len)
{
const struct counter_count_enum_ext *const e = priv;
ssize_t index;
int err;
if (!e->set)
return -EINVAL;
index = __sysfs_match_string(e->items, e->num_items, buf);
if (index < 0)
return index;
err = e->set(counter, count, index);
if (err)
return err;
return len;
}
EXPORT_SYMBOL_GPL(counter_count_enum_write);
ssize_t counter_count_enum_available_read(struct counter_device *counter,
struct counter_count *count,
void *priv, char *buf)
{
const struct counter_count_enum_ext *const e = priv;
size_t i;
size_t len = 0;
if (!e->num_items)
return 0;
for (i = 0; i < e->num_items; i++)
len += sprintf(buf + len, "%s\n", e->items[i]);
return len;
}
EXPORT_SYMBOL_GPL(counter_count_enum_available_read);
ssize_t counter_device_enum_read(struct counter_device *counter, void *priv,
char *buf)
{
const struct counter_device_enum_ext *const e = priv;
int err;
size_t index;
if (!e->get)
return -EINVAL;
err = e->get(counter, &index);
if (err)
return err;
if (index >= e->num_items)
return -EINVAL;
return sprintf(buf, "%s\n", e->items[index]);
}
EXPORT_SYMBOL_GPL(counter_device_enum_read);
ssize_t counter_device_enum_write(struct counter_device *counter, void *priv,
const char *buf, size_t len)
{
const struct counter_device_enum_ext *const e = priv;
ssize_t index;
int err;
if (!e->set)
return -EINVAL;
index = __sysfs_match_string(e->items, e->num_items, buf);
if (index < 0)
return index;
err = e->set(counter, index);
if (err)
return err;
return len;
}
EXPORT_SYMBOL_GPL(counter_device_enum_write);
ssize_t counter_device_enum_available_read(struct counter_device *counter,
void *priv, char *buf)
{
const struct counter_device_enum_ext *const e = priv;
size_t i;
size_t len = 0;
if (!e->num_items)
return 0;
for (i = 0; i < e->num_items; i++)
len += sprintf(buf + len, "%s\n", e->items[i]);
return len;
}
EXPORT_SYMBOL_GPL(counter_device_enum_available_read);
static const char *const counter_signal_level_str[] = {
[COUNTER_SIGNAL_LEVEL_LOW] = "low",
[COUNTER_SIGNAL_LEVEL_HIGH] = "high"
};
/**
* counter_signal_read_value_set - set counter_signal_read_value data
* @val: counter_signal_read_value structure to set
* @type: property Signal data represents
* @data: Signal data
*
* This function sets an opaque counter_signal_read_value structure with the
* provided Signal data.
*/
void counter_signal_read_value_set(struct counter_signal_read_value *const val,
const enum counter_signal_value_type type,
void *const data)
{
if (type == COUNTER_SIGNAL_LEVEL)
val->len = sprintf(val->buf, "%s\n",
counter_signal_level_str[*(enum counter_signal_level *)data]);
else
val->len = 0;
}
EXPORT_SYMBOL_GPL(counter_signal_read_value_set);
/**
* counter_count_read_value_set - set counter_count_read_value data
* @val: counter_count_read_value structure to set
* @type: property Count data represents
* @data: Count data
*
* This function sets an opaque counter_count_read_value structure with the
* provided Count data.
*/
void counter_count_read_value_set(struct counter_count_read_value *const val,
const enum counter_count_value_type type,
void *const data)
{
switch (type) {
case COUNTER_COUNT_POSITION:
val->len = sprintf(val->buf, "%lu\n", *(unsigned long *)data);
break;
default:
val->len = 0;
}
}
EXPORT_SYMBOL_GPL(counter_count_read_value_set);
/**
* counter_count_write_value_get - get counter_count_write_value data
* @data: Count data
* @type: property Count data represents
* @val: counter_count_write_value structure containing data
*
* This function extracts Count data from the provided opaque
* counter_count_write_value structure and stores it at the address provided by
* @data.
*
* RETURNS:
* 0 on success, negative error number on failure.
*/
int counter_count_write_value_get(void *const data,
const enum counter_count_value_type type,
const struct counter_count_write_value *const val)
{
int err;
switch (type) {
case COUNTER_COUNT_POSITION:
err = kstrtoul(val->buf, 0, data);
if (err)
return err;
break;
}
return 0;
}
EXPORT_SYMBOL_GPL(counter_count_write_value_get);
struct counter_attr_parm {
struct counter_device_attr_group *group;
const char *prefix;
const char *name;
ssize_t (*show)(struct device *dev, struct device_attribute *attr,
char *buf);
ssize_t (*store)(struct device *dev, struct device_attribute *attr,
const char *buf, size_t len);
void *component;
};
struct counter_device_attr {
struct device_attribute dev_attr;
struct list_head l;
void *component;
};
static int counter_attribute_create(const struct counter_attr_parm *const parm)
{
struct counter_device_attr *counter_attr;
struct device_attribute *dev_attr;
int err;
struct list_head *const attr_list = &parm->group->attr_list;
/* Allocate a Counter device attribute */
counter_attr = kzalloc(sizeof(*counter_attr), GFP_KERNEL);
if (!counter_attr)
return -ENOMEM;
dev_attr = &counter_attr->dev_attr;
sysfs_attr_init(&dev_attr->attr);
/* Configure device attribute */
dev_attr->attr.name = kasprintf(GFP_KERNEL, "%s%s", parm->prefix,
parm->name);
if (!dev_attr->attr.name) {
err = -ENOMEM;
goto err_free_counter_attr;
}
if (parm->show) {
dev_attr->attr.mode |= 0444;
dev_attr->show = parm->show;
}
if (parm->store) {
dev_attr->attr.mode |= 0200;
dev_attr->store = parm->store;
}
/* Store associated Counter component with attribute */
counter_attr->component = parm->component;
/* Keep track of the attribute for later cleanup */
list_add(&counter_attr->l, attr_list);
parm->group->num_attr++;
return 0;
err_free_counter_attr:
kfree(counter_attr);
return err;
}
#define to_counter_attr(_dev_attr) \
container_of(_dev_attr, struct counter_device_attr, dev_attr)
struct counter_signal_unit {
struct counter_signal *signal;
};
static ssize_t counter_signal_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct counter_device *const counter = dev_get_drvdata(dev);
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_signal_unit *const component = devattr->component;
struct counter_signal *const signal = component->signal;
int err;
struct counter_signal_read_value val = { .buf = buf };
err = counter->ops->signal_read(counter, signal, &val);
if (err)
return err;
return val.len;
}
struct counter_name_unit {
const char *name;
};
static ssize_t counter_device_attr_name_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
const struct counter_name_unit *const comp = to_counter_attr(attr)->component;
return sprintf(buf, "%s\n", comp->name);
}
static int counter_name_attribute_create(
struct counter_device_attr_group *const group,
const char *const name)
{
struct counter_name_unit *name_comp;
struct counter_attr_parm parm;
int err;
/* Skip if no name */
if (!name)
return 0;
/* Allocate name attribute component */
name_comp = kmalloc(sizeof(*name_comp), GFP_KERNEL);
if (!name_comp)
return -ENOMEM;
name_comp->name = name;
/* Allocate Signal name attribute */
parm.group = group;
parm.prefix = "";
parm.name = "name";
parm.show = counter_device_attr_name_show;
parm.store = NULL;
parm.component = name_comp;
err = counter_attribute_create(&parm);
if (err)
goto err_free_name_comp;
return 0;
err_free_name_comp:
kfree(name_comp);
return err;
}
struct counter_signal_ext_unit {
struct counter_signal *signal;
const struct counter_signal_ext *ext;
};
static ssize_t counter_signal_ext_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_signal_ext_unit *const comp = devattr->component;
const struct counter_signal_ext *const ext = comp->ext;
return ext->read(dev_get_drvdata(dev), comp->signal, ext->priv, buf);
}
static ssize_t counter_signal_ext_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_signal_ext_unit *const comp = devattr->component;
const struct counter_signal_ext *const ext = comp->ext;
return ext->write(dev_get_drvdata(dev), comp->signal, ext->priv, buf,
len);
}
static void counter_device_attr_list_free(struct list_head *attr_list)
{
struct counter_device_attr *p, *n;
list_for_each_entry_safe(p, n, attr_list, l) {
/* free attribute name and associated component memory */
kfree(p->dev_attr.attr.name);
kfree(p->component);
list_del(&p->l);
kfree(p);
}
}
static int counter_signal_ext_register(
struct counter_device_attr_group *const group,
struct counter_signal *const signal)
{
const size_t num_ext = signal->num_ext;
size_t i;
const struct counter_signal_ext *ext;
struct counter_signal_ext_unit *signal_ext_comp;
struct counter_attr_parm parm;
int err;
/* Create an attribute for each extension */
for (i = 0 ; i < num_ext; i++) {
ext = signal->ext + i;
/* Allocate signal_ext attribute component */
signal_ext_comp = kmalloc(sizeof(*signal_ext_comp), GFP_KERNEL);
if (!signal_ext_comp) {
err = -ENOMEM;
goto err_free_attr_list;
}
signal_ext_comp->signal = signal;
signal_ext_comp->ext = ext;
/* Allocate a Counter device attribute */
parm.group = group;
parm.prefix = "";
parm.name = ext->name;
parm.show = (ext->read) ? counter_signal_ext_show : NULL;
parm.store = (ext->write) ? counter_signal_ext_store : NULL;
parm.component = signal_ext_comp;
err = counter_attribute_create(&parm);
if (err) {
kfree(signal_ext_comp);
goto err_free_attr_list;
}
}
return 0;
err_free_attr_list:
counter_device_attr_list_free(&group->attr_list);
return err;
}
static int counter_signal_attributes_create(
struct counter_device_attr_group *const group,
const struct counter_device *const counter,
struct counter_signal *const signal)
{
struct counter_signal_unit *signal_comp;
struct counter_attr_parm parm;
int err;
/* Allocate Signal attribute component */
signal_comp = kmalloc(sizeof(*signal_comp), GFP_KERNEL);
if (!signal_comp)
return -ENOMEM;
signal_comp->signal = signal;
/* Create main Signal attribute */
parm.group = group;
parm.prefix = "";
parm.name = "signal";
parm.show = (counter->ops->signal_read) ? counter_signal_show : NULL;
parm.store = NULL;
parm.component = signal_comp;
err = counter_attribute_create(&parm);
if (err) {
kfree(signal_comp);
return err;
}
/* Create Signal name attribute */
err = counter_name_attribute_create(group, signal->name);
if (err)
goto err_free_attr_list;
/* Register Signal extension attributes */
err = counter_signal_ext_register(group, signal);
if (err)
goto err_free_attr_list;
return 0;
err_free_attr_list:
counter_device_attr_list_free(&group->attr_list);
return err;
}
static int counter_signals_register(
struct counter_device_attr_group *const groups_list,
const struct counter_device *const counter)
{
const size_t num_signals = counter->num_signals;
size_t i;
struct counter_signal *signal;
const char *name;
int err;
/* Register each Signal */
for (i = 0; i < num_signals; i++) {
signal = counter->signals + i;
/* Generate Signal attribute directory name */
name = kasprintf(GFP_KERNEL, "signal%d", signal->id);
if (!name) {
err = -ENOMEM;
goto err_free_attr_groups;
}
groups_list[i].attr_group.name = name;
/* Create all attributes associated with Signal */
err = counter_signal_attributes_create(groups_list + i, counter,
signal);
if (err)
goto err_free_attr_groups;
}
return 0;
err_free_attr_groups:
do {
kfree(groups_list[i].attr_group.name);
counter_device_attr_list_free(&groups_list[i].attr_list);
} while (i--);
return err;
}
static const char *const counter_synapse_action_str[] = {
[COUNTER_SYNAPSE_ACTION_NONE] = "none",
[COUNTER_SYNAPSE_ACTION_RISING_EDGE] = "rising edge",
[COUNTER_SYNAPSE_ACTION_FALLING_EDGE] = "falling edge",
[COUNTER_SYNAPSE_ACTION_BOTH_EDGES] = "both edges"
};
struct counter_action_unit {
struct counter_synapse *synapse;
struct counter_count *count;
};
static ssize_t counter_action_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
const struct counter_device_attr *const devattr = to_counter_attr(attr);
int err;
struct counter_device *const counter = dev_get_drvdata(dev);
const struct counter_action_unit *const component = devattr->component;
struct counter_count *const count = component->count;
struct counter_synapse *const synapse = component->synapse;
size_t action_index;
enum counter_synapse_action action;
err = counter->ops->action_get(counter, count, synapse, &action_index);
if (err)
return err;
synapse->action = action_index;
action = synapse->actions_list[action_index];
return sprintf(buf, "%s\n", counter_synapse_action_str[action]);
}
static ssize_t counter_action_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_action_unit *const component = devattr->component;
struct counter_synapse *const synapse = component->synapse;
size_t action_index;
const size_t num_actions = synapse->num_actions;
enum counter_synapse_action action;
int err;
struct counter_device *const counter = dev_get_drvdata(dev);
struct counter_count *const count = component->count;
/* Find requested action mode */
for (action_index = 0; action_index < num_actions; action_index++) {
action = synapse->actions_list[action_index];
if (sysfs_streq(buf, counter_synapse_action_str[action]))
break;
}
/* If requested action mode not found */
if (action_index >= num_actions)
return -EINVAL;
err = counter->ops->action_set(counter, count, synapse, action_index);
if (err)
return err;
synapse->action = action_index;
return len;
}
struct counter_action_avail_unit {
const enum counter_synapse_action *actions_list;
size_t num_actions;
};
static ssize_t counter_synapse_action_available_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_action_avail_unit *const component = devattr->component;
size_t i;
enum counter_synapse_action action;
ssize_t len = 0;
for (i = 0; i < component->num_actions; i++) {
action = component->actions_list[i];
len += sprintf(buf + len, "%s\n",
counter_synapse_action_str[action]);
}
return len;
}
static int counter_synapses_register(
struct counter_device_attr_group *const group,
const struct counter_device *const counter,
struct counter_count *const count, const char *const count_attr_name)
{
size_t i;
struct counter_synapse *synapse;
const char *prefix;
struct counter_action_unit *action_comp;
struct counter_attr_parm parm;
int err;
struct counter_action_avail_unit *avail_comp;
/* Register each Synapse */
for (i = 0; i < count->num_synapses; i++) {
synapse = count->synapses + i;
/* Generate attribute prefix */
prefix = kasprintf(GFP_KERNEL, "signal%d_",
synapse->signal->id);
if (!prefix) {
err = -ENOMEM;
goto err_free_attr_list;
}
/* Allocate action attribute component */
action_comp = kmalloc(sizeof(*action_comp), GFP_KERNEL);
if (!action_comp) {
err = -ENOMEM;
goto err_free_prefix;
}
action_comp->synapse = synapse;
action_comp->count = count;
/* Create action attribute */
parm.group = group;
parm.prefix = prefix;
parm.name = "action";
parm.show = (counter->ops->action_get) ? counter_action_show : NULL;
parm.store = (counter->ops->action_set) ? counter_action_store : NULL;
parm.component = action_comp;
err = counter_attribute_create(&parm);
if (err) {
kfree(action_comp);
goto err_free_prefix;
}
/* Allocate action available attribute component */
avail_comp = kmalloc(sizeof(*avail_comp), GFP_KERNEL);
if (!avail_comp) {
err = -ENOMEM;
goto err_free_prefix;
}
avail_comp->actions_list = synapse->actions_list;
avail_comp->num_actions = synapse->num_actions;
/* Create action_available attribute */
parm.group = group;
parm.prefix = prefix;
parm.name = "action_available";
parm.show = counter_synapse_action_available_show;
parm.store = NULL;
parm.component = avail_comp;
err = counter_attribute_create(&parm);
if (err) {
kfree(avail_comp);
goto err_free_prefix;
}
kfree(prefix);
}
return 0;
err_free_prefix:
kfree(prefix);
err_free_attr_list:
counter_device_attr_list_free(&group->attr_list);
return err;
}
struct counter_count_unit {
struct counter_count *count;
};
static ssize_t counter_count_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct counter_device *const counter = dev_get_drvdata(dev);
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_count_unit *const component = devattr->component;
struct counter_count *const count = component->count;
int err;
struct counter_count_read_value val = { .buf = buf };
err = counter->ops->count_read(counter, count, &val);
if (err)
return err;
return val.len;
}
static ssize_t counter_count_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct counter_device *const counter = dev_get_drvdata(dev);
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_count_unit *const component = devattr->component;
struct counter_count *const count = component->count;
int err;
struct counter_count_write_value val = { .buf = buf };
err = counter->ops->count_write(counter, count, &val);
if (err)
return err;
return len;
}
static const char *const counter_count_function_str[] = {
[COUNTER_COUNT_FUNCTION_INCREASE] = "increase",
[COUNTER_COUNT_FUNCTION_DECREASE] = "decrease",
[COUNTER_COUNT_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
[COUNTER_COUNT_FUNCTION_QUADRATURE_X4] = "quadrature x4"
};
static ssize_t counter_function_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
int err;
struct counter_device *const counter = dev_get_drvdata(dev);
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_count_unit *const component = devattr->component;
struct counter_count *const count = component->count;
size_t func_index;
enum counter_count_function function;
err = counter->ops->function_get(counter, count, &func_index);
if (err)
return err;
count->function = func_index;
function = count->functions_list[func_index];
return sprintf(buf, "%s\n", counter_count_function_str[function]);
}
static ssize_t counter_function_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_count_unit *const component = devattr->component;
struct counter_count *const count = component->count;
const size_t num_functions = count->num_functions;
size_t func_index;
enum counter_count_function function;
int err;
struct counter_device *const counter = dev_get_drvdata(dev);
/* Find requested Count function mode */
for (func_index = 0; func_index < num_functions; func_index++) {
function = count->functions_list[func_index];
if (sysfs_streq(buf, counter_count_function_str[function]))
break;
}
/* Return error if requested Count function mode not found */
if (func_index >= num_functions)
return -EINVAL;
err = counter->ops->function_set(counter, count, func_index);
if (err)
return err;
count->function = func_index;
return len;
}
struct counter_count_ext_unit {
struct counter_count *count;
const struct counter_count_ext *ext;
};
static ssize_t counter_count_ext_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_count_ext_unit *const comp = devattr->component;
const struct counter_count_ext *const ext = comp->ext;
return ext->read(dev_get_drvdata(dev), comp->count, ext->priv, buf);
}
static ssize_t counter_count_ext_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_count_ext_unit *const comp = devattr->component;
const struct counter_count_ext *const ext = comp->ext;
return ext->write(dev_get_drvdata(dev), comp->count, ext->priv, buf,
len);
}
static int counter_count_ext_register(
struct counter_device_attr_group *const group,
struct counter_count *const count)
{
size_t i;
const struct counter_count_ext *ext;
struct counter_count_ext_unit *count_ext_comp;
struct counter_attr_parm parm;
int err;
/* Create an attribute for each extension */
for (i = 0 ; i < count->num_ext; i++) {
ext = count->ext + i;
/* Allocate count_ext attribute component */
count_ext_comp = kmalloc(sizeof(*count_ext_comp), GFP_KERNEL);
if (!count_ext_comp) {
err = -ENOMEM;
goto err_free_attr_list;
}
count_ext_comp->count = count;
count_ext_comp->ext = ext;
/* Allocate count_ext attribute */
parm.group = group;
parm.prefix = "";
parm.name = ext->name;
parm.show = (ext->read) ? counter_count_ext_show : NULL;
parm.store = (ext->write) ? counter_count_ext_store : NULL;
parm.component = count_ext_comp;
err = counter_attribute_create(&parm);
if (err) {
kfree(count_ext_comp);
goto err_free_attr_list;
}
}
return 0;
err_free_attr_list:
counter_device_attr_list_free(&group->attr_list);
return err;
}
struct counter_func_avail_unit {
const enum counter_count_function *functions_list;
size_t num_functions;
};
static ssize_t counter_count_function_available_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_func_avail_unit *const component = devattr->component;
const enum counter_count_function *const func_list = component->functions_list;
const size_t num_functions = component->num_functions;
size_t i;
enum counter_count_function function;
ssize_t len = 0;
for (i = 0; i < num_functions; i++) {
function = func_list[i];
len += sprintf(buf + len, "%s\n",
counter_count_function_str[function]);
}
return len;
}
static int counter_count_attributes_create(
struct counter_device_attr_group *const group,
const struct counter_device *const counter,
struct counter_count *const count)
{
struct counter_count_unit *count_comp;
struct counter_attr_parm parm;
int err;
struct counter_count_unit *func_comp;
struct counter_func_avail_unit *avail_comp;
/* Allocate count attribute component */
count_comp = kmalloc(sizeof(*count_comp), GFP_KERNEL);
if (!count_comp)
return -ENOMEM;
count_comp->count = count;
/* Create main Count attribute */
parm.group = group;
parm.prefix = "";
parm.name = "count";
parm.show = (counter->ops->count_read) ? counter_count_show : NULL;
parm.store = (counter->ops->count_write) ? counter_count_store : NULL;
parm.component = count_comp;
err = counter_attribute_create(&parm);
if (err) {
kfree(count_comp);
return err;
}
/* Allocate function attribute component */
func_comp = kmalloc(sizeof(*func_comp), GFP_KERNEL);
if (!func_comp) {
err = -ENOMEM;
goto err_free_attr_list;
}
func_comp->count = count;
/* Create Count function attribute */
parm.group = group;
parm.prefix = "";
parm.name = "function";
parm.show = (counter->ops->function_get) ? counter_function_show : NULL;
parm.store = (counter->ops->function_set) ? counter_function_store : NULL;
parm.component = func_comp;
err = counter_attribute_create(&parm);
if (err) {
kfree(func_comp);
goto err_free_attr_list;
}
/* Allocate function available attribute component */
avail_comp = kmalloc(sizeof(*avail_comp), GFP_KERNEL);
if (!avail_comp) {
err = -ENOMEM;
goto err_free_attr_list;
}
avail_comp->functions_list = count->functions_list;
avail_comp->num_functions = count->num_functions;
/* Create Count function_available attribute */
parm.group = group;
parm.prefix = "";
parm.name = "function_available";
parm.show = counter_count_function_available_show;
parm.store = NULL;
parm.component = avail_comp;
err = counter_attribute_create(&parm);
if (err) {
kfree(avail_comp);
goto err_free_attr_list;
}
/* Create Count name attribute */
err = counter_name_attribute_create(group, count->name);
if (err)
goto err_free_attr_list;
/* Register Count extension attributes */
err = counter_count_ext_register(group, count);
if (err)
goto err_free_attr_list;
return 0;
err_free_attr_list:
counter_device_attr_list_free(&group->attr_list);
return err;
}
static int counter_counts_register(
struct counter_device_attr_group *const groups_list,
const struct counter_device *const counter)
{
size_t i;
struct counter_count *count;
const char *name;
int err;
/* Register each Count */
for (i = 0; i < counter->num_counts; i++) {
count = counter->counts + i;
/* Generate Count attribute directory name */
name = kasprintf(GFP_KERNEL, "count%d", count->id);
if (!name) {
err = -ENOMEM;
goto err_free_attr_groups;
}
groups_list[i].attr_group.name = name;
/* Register the Synapses associated with each Count */
err = counter_synapses_register(groups_list + i, counter, count,
name);
if (err)
goto err_free_attr_groups;
/* Create all attributes associated with Count */
err = counter_count_attributes_create(groups_list + i, counter,
count);
if (err)
goto err_free_attr_groups;
}
return 0;
err_free_attr_groups:
do {
kfree(groups_list[i].attr_group.name);
counter_device_attr_list_free(&groups_list[i].attr_list);
} while (i--);
return err;
}
struct counter_size_unit {
size_t size;
};
static ssize_t counter_device_attr_size_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
const struct counter_size_unit *const comp = to_counter_attr(attr)->component;
return sprintf(buf, "%zu\n", comp->size);
}
static int counter_size_attribute_create(
struct counter_device_attr_group *const group,
const size_t size, const char *const name)
{
struct counter_size_unit *size_comp;
struct counter_attr_parm parm;
int err;
/* Allocate size attribute component */
size_comp = kmalloc(sizeof(*size_comp), GFP_KERNEL);
if (!size_comp)
return -ENOMEM;
size_comp->size = size;
parm.group = group;
parm.prefix = "";
parm.name = name;
parm.show = counter_device_attr_size_show;
parm.store = NULL;
parm.component = size_comp;
err = counter_attribute_create(&parm);
if (err)
goto err_free_size_comp;
return 0;
err_free_size_comp:
kfree(size_comp);
return err;
}
struct counter_ext_unit {
const struct counter_device_ext *ext;
};
static ssize_t counter_device_ext_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_ext_unit *const component = devattr->component;
const struct counter_device_ext *const ext = component->ext;
return ext->read(dev_get_drvdata(dev), ext->priv, buf);
}
static ssize_t counter_device_ext_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
const struct counter_device_attr *const devattr = to_counter_attr(attr);
const struct counter_ext_unit *const component = devattr->component;
const struct counter_device_ext *const ext = component->ext;
return ext->write(dev_get_drvdata(dev), ext->priv, buf, len);
}
static int counter_device_ext_register(
struct counter_device_attr_group *const group,
struct counter_device *const counter)
{
size_t i;
struct counter_ext_unit *ext_comp;
struct counter_attr_parm parm;
int err;
/* Create an attribute for each extension */
for (i = 0 ; i < counter->num_ext; i++) {
/* Allocate extension attribute component */
ext_comp = kmalloc(sizeof(*ext_comp), GFP_KERNEL);
if (!ext_comp) {
err = -ENOMEM;
goto err_free_attr_list;
}
ext_comp->ext = counter->ext + i;
/* Allocate extension attribute */
parm.group = group;
parm.prefix = "";
parm.name = counter->ext[i].name;
parm.show = (counter->ext[i].read) ? counter_device_ext_show : NULL;
parm.store = (counter->ext[i].write) ? counter_device_ext_store : NULL;
parm.component = ext_comp;
err = counter_attribute_create(&parm);
if (err) {
kfree(ext_comp);
goto err_free_attr_list;
}
}
return 0;
err_free_attr_list:
counter_device_attr_list_free(&group->attr_list);
return err;
}
static int counter_global_attr_register(
struct counter_device_attr_group *const group,
struct counter_device *const counter)
{
int err;
/* Create name attribute */
err = counter_name_attribute_create(group, counter->name);
if (err)
return err;
/* Create num_counts attribute */
err = counter_size_attribute_create(group, counter->num_counts,
"num_counts");
if (err)
goto err_free_attr_list;
/* Create num_signals attribute */
err = counter_size_attribute_create(group, counter->num_signals,
"num_signals");
if (err)
goto err_free_attr_list;
/* Register Counter device extension attributes */
err = counter_device_ext_register(group, counter);
if (err)
goto err_free_attr_list;
return 0;
err_free_attr_list:
counter_device_attr_list_free(&group->attr_list);
return err;
}
static void counter_device_groups_list_free(
struct counter_device_attr_group *const groups_list,
const size_t num_groups)
{
struct counter_device_attr_group *group;
size_t i;
/* loop through all attribute groups (signals, counts, global, etc.) */
for (i = 0; i < num_groups; i++) {
group = groups_list + i;
/* free all attribute group and associated attributes memory */
kfree(group->attr_group.name);
kfree(group->attr_group.attrs);
counter_device_attr_list_free(&group->attr_list);
}
kfree(groups_list);
}
static int counter_device_groups_list_prepare(
struct counter_device *const counter)
{
const size_t total_num_groups =
counter->num_signals + counter->num_counts + 1;
struct counter_device_attr_group *groups_list;
size_t i;
int err;
size_t num_groups = 0;
/* Allocate space for attribute groups (signals, counts, and ext) */
groups_list = kcalloc(total_num_groups, sizeof(*groups_list),
GFP_KERNEL);
if (!groups_list)
return -ENOMEM;
/* Initialize attribute lists */
for (i = 0; i < total_num_groups; i++)
INIT_LIST_HEAD(&groups_list[i].attr_list);
/* Register Signals */
err = counter_signals_register(groups_list, counter);
if (err)
goto err_free_groups_list;
num_groups += counter->num_signals;
/* Register Counts and respective Synapses */
err = counter_counts_register(groups_list + num_groups, counter);
if (err)
goto err_free_groups_list;
num_groups += counter->num_counts;
/* Register Counter global attributes */
err = counter_global_attr_register(groups_list + num_groups, counter);
if (err)
goto err_free_groups_list;
num_groups++;
/* Store groups_list in device_state */
counter->device_state->groups_list = groups_list;
counter->device_state->num_groups = num_groups;
return 0;
err_free_groups_list:
counter_device_groups_list_free(groups_list, num_groups);
return err;
}
static int counter_device_groups_prepare(
struct counter_device_state *const device_state)
{
size_t i, j;
struct counter_device_attr_group *group;
int err;
struct counter_device_attr *p;
/* Allocate attribute groups for association with device */
device_state->groups = kcalloc(device_state->num_groups + 1,
sizeof(*device_state->groups),
GFP_KERNEL);
if (!device_state->groups)
return -ENOMEM;
/* Prepare each group of attributes for association */
for (i = 0; i < device_state->num_groups; i++) {
group = device_state->groups_list + i;
/* Allocate space for attribute pointers in attribute group */
group->attr_group.attrs = kcalloc(group->num_attr + 1,
sizeof(*group->attr_group.attrs), GFP_KERNEL);
if (!group->attr_group.attrs) {
err = -ENOMEM;
goto err_free_groups;
}
/* Add attribute pointers to attribute group */
j = 0;
list_for_each_entry(p, &group->attr_list, l)
group->attr_group.attrs[j++] = &p->dev_attr.attr;
/* Group attributes in attribute group */
device_state->groups[i] = &group->attr_group;
}
/* Associate attributes with device */
device_state->dev.groups = device_state->groups;
return 0;
err_free_groups:
do {
group = device_state->groups_list + i;
kfree(group->attr_group.attrs);
group->attr_group.attrs = NULL;
} while (i--);
kfree(device_state->groups);
return err;
}
/* Provides a unique ID for each counter device */
static DEFINE_IDA(counter_ida);
static void counter_device_release(struct device *dev)
{
struct counter_device *const counter = dev_get_drvdata(dev);
struct counter_device_state *const device_state = counter->device_state;
kfree(device_state->groups);
counter_device_groups_list_free(device_state->groups_list,
device_state->num_groups);
ida_simple_remove(&counter_ida, device_state->id);
kfree(device_state);
}
static struct device_type counter_device_type = {
.name = "counter_device",
.release = counter_device_release
};
static struct bus_type counter_bus_type = {
.name = "counter"
};
/**
* counter_register - register Counter to the system
* @counter: pointer to Counter to register
*
* This function registers a Counter to the system. A sysfs "counter" directory
* will be created and populated with sysfs attributes correlating with the
* Counter Signals, Synapses, and Counts respectively.
*/
int counter_register(struct counter_device *const counter)
{
struct counter_device_state *device_state;
int err;
/* Allocate internal state container for Counter device */
device_state = kzalloc(sizeof(*device_state), GFP_KERNEL);
if (!device_state)
return -ENOMEM;
counter->device_state = device_state;
/* Acquire unique ID */
device_state->id = ida_simple_get(&counter_ida, 0, 0, GFP_KERNEL);
if (device_state->id < 0) {
err = device_state->id;
goto err_free_device_state;
}
/* Configure device structure for Counter */
device_state->dev.type = &counter_device_type;
device_state->dev.bus = &counter_bus_type;
if (counter->parent) {
device_state->dev.parent = counter->parent;
device_state->dev.of_node = counter->parent->of_node;
}
dev_set_name(&device_state->dev, "counter%d", device_state->id);
device_initialize(&device_state->dev);
dev_set_drvdata(&device_state->dev, counter);
/* Prepare device attributes */
err = counter_device_groups_list_prepare(counter);
if (err)
goto err_free_id;
/* Organize device attributes to groups and match to device */
err = counter_device_groups_prepare(device_state);
if (err)
goto err_free_groups_list;
/* Add device to system */
err = device_add(&device_state->dev);
if (err)
goto err_free_groups;
return 0;
err_free_groups:
kfree(device_state->groups);
err_free_groups_list:
counter_device_groups_list_free(device_state->groups_list,
device_state->num_groups);
err_free_id:
ida_simple_remove(&counter_ida, device_state->id);
err_free_device_state:
kfree(device_state);
return err;
}
EXPORT_SYMBOL_GPL(counter_register);
/**
* counter_unregister - unregister Counter from the system
* @counter: pointer to Counter to unregister
*
* The Counter is unregistered from the system; all allocated memory is freed.
*/
void counter_unregister(struct counter_device *const counter)
{
if (counter)
device_del(&counter->device_state->dev);
}
EXPORT_SYMBOL_GPL(counter_unregister);
static void devm_counter_unreg(struct device *dev, void *res)
{
counter_unregister(*(struct counter_device **)res);
}
/**
* devm_counter_register - Resource-managed counter_register
* @dev: device to allocate counter_device for
* @counter: pointer to Counter to register
*
* Managed counter_register. The Counter registered with this function is
* automatically unregistered on driver detach. This function calls
* counter_register internally. Refer to that function for more information.
*
* If an Counter registered with this function needs to be unregistered
* separately, devm_counter_unregister must be used.
*
* RETURNS:
* 0 on success, negative error number on failure.
*/
int devm_counter_register(struct device *dev,
struct counter_device *const counter)
{
struct counter_device **ptr;
int ret;
ptr = devres_alloc(devm_counter_unreg, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return -ENOMEM;
ret = counter_register(counter);
if (!ret) {
*ptr = counter;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return ret;
}
EXPORT_SYMBOL_GPL(devm_counter_register);
static int devm_counter_match(struct device *dev, void *res, void *data)
{
struct counter_device **r = res;
if (!r || !*r) {
WARN_ON(!r || !*r);
return 0;
}
return *r == data;
}
/**
* devm_counter_unregister - Resource-managed counter_unregister
* @dev: device this counter_device belongs to
* @counter: pointer to Counter associated with the device
*
* Unregister Counter registered with devm_counter_register.
*/
void devm_counter_unregister(struct device *dev,
struct counter_device *const counter)
{
int rc;
rc = devres_release(dev, devm_counter_unreg, devm_counter_match,
counter);
WARN_ON(rc);
}
EXPORT_SYMBOL_GPL(devm_counter_unregister);
static int __init counter_init(void)
{
return bus_register(&counter_bus_type);
}
static void __exit counter_exit(void)
{
bus_unregister(&counter_bus_type);
}
subsys_initcall(counter_init);
module_exit(counter_exit);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("Generic Counter interface");
MODULE_LICENSE("GPL v2");