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nvmem: add support for cell lookups from machine code 

Add a way for machine code users to associate devices with nvmem cells.

This restores the support for non-DT systems but following a different
approach. Cells must now be associated with devices using provided
routines and data structures before they can be retrieved using
nvmem_cell_get().

It's still possible to define cells statically in nvmem_config but
cells created this way still need to be associated with consumers using
lookup entries.

Note that nvmem_find() must be moved higher in the source file as we
want to call it from __nvmem_device_get() for devices that don't have
a device node.

The signature of __nvmem_device_get() is also changed as it's no longer
used to retrieve cells.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Bartosz Golaszewski 2018-09-21 06:40:17 -07:00 committed by Greg Kroah-Hartman
parent e888d445ac
commit 506157be06
2 changed files with 131 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

129
drivers/nvmem/core.c
View File

@ -62,6 +62,9 @@ static DEFINE_IDA(nvmem_ida);
static DEFINE_MUTEX(nvmem_cell_mutex);
static LIST_HEAD(nvmem_cell_tables);
static DEFINE_MUTEX(nvmem_lookup_mutex);
static LIST_HEAD(nvmem_lookup_list);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
static struct lock_class_key eeprom_lock_key;
#endif
@ -283,6 +286,18 @@ static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np)
return to_nvmem_device(d);
}
static struct nvmem_device *nvmem_find(const char *name)
{
struct device *d;
d = bus_find_device_by_name(&nvmem_bus_type, NULL, name);
if (!d)
return NULL;
return to_nvmem_device(d);
}
static void nvmem_cell_drop(struct nvmem_cell *cell)
{
mutex_lock(&nvmem_mutex);
@ -472,6 +487,21 @@ nvmem_find_cell_by_index(struct nvmem_device *nvmem, int index)
return cell;
}
static struct nvmem_cell *
nvmem_find_cell_by_name(struct nvmem_device *nvmem, const char *cell_id)
{
struct nvmem_cell *cell = NULL;
mutex_lock(&nvmem_mutex);
list_for_each_entry(cell, &nvmem->cells, node) {
if (strcmp(cell_id, cell->name) == 0)
break;
}
mutex_unlock(&nvmem_mutex);
return cell;
}
static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
{
struct device_node *parent, *child;
@ -719,16 +749,12 @@ int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
EXPORT_SYMBOL(devm_nvmem_unregister);
static struct nvmem_device *__nvmem_device_get(struct device_node *np,
struct nvmem_cell **cellp,
const char *cell_id)
const char *nvmem_name)
{
struct nvmem_device *nvmem = NULL;
if (!np)
return ERR_PTR(-ENOENT);
mutex_lock(&nvmem_mutex);
nvmem = of_nvmem_find(np);
nvmem = np ? of_nvmem_find(np) : nvmem_find(nvmem_name);
mutex_unlock(&nvmem_mutex);
if (!nvmem)
return ERR_PTR(-EPROBE_DEFER);
@ -752,18 +778,6 @@ static void __nvmem_device_put(struct nvmem_device *nvmem)
kref_put(&nvmem->refcnt, nvmem_device_release);
}
static struct nvmem_device *nvmem_find(const char *name)
{
struct device *d;
d = bus_find_device_by_name(&nvmem_bus_type, NULL, name);
if (!d)
return ERR_PTR(-ENOENT);
return to_nvmem_device(d);
}
#if IS_ENABLED(CONFIG_OF)
/**
* of_nvmem_device_get() - Get nvmem device from a given id
@ -786,7 +800,7 @@ struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
if (!nvmem_np)
return ERR_PTR(-EINVAL);
return __nvmem_device_get(nvmem_np, NULL, NULL);
return __nvmem_device_get(nvmem_np, NULL);
}
EXPORT_SYMBOL_GPL(of_nvmem_device_get);
#endif
@ -890,15 +904,43 @@ struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
}
EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
static struct nvmem_cell *
nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
{
struct nvmem_cell *cell = NULL;
struct nvmem_cell *cell = ERR_PTR(-ENOENT);
struct nvmem_cell_lookup *lookup;
struct nvmem_device *nvmem;
const char *dev_id;
nvmem = __nvmem_device_get(NULL, &cell, cell_id);
if (IS_ERR(nvmem))
return ERR_CAST(nvmem);
if (!dev)
return ERR_PTR(-EINVAL);
dev_id = dev_name(dev);
mutex_lock(&nvmem_lookup_mutex);
list_for_each_entry(lookup, &nvmem_lookup_list, node) {
if ((strcmp(lookup->dev_id, dev_id) == 0) &&
(strcmp(lookup->con_id, con_id) == 0)) {
/* This is the right entry. */
nvmem = __nvmem_device_get(NULL, lookup->nvmem_name);
if (!nvmem) {
/* Provider may not be registered yet. */
cell = ERR_PTR(-EPROBE_DEFER);
goto out;
}
cell = nvmem_find_cell_by_name(nvmem,
lookup->cell_name);
if (!cell) {
__nvmem_device_put(nvmem);
goto out;
}
}
}
out:
mutex_unlock(&nvmem_lookup_mutex);
return cell;
}
@ -935,7 +977,7 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
if (!nvmem_np)
return ERR_PTR(-EINVAL);
nvmem = __nvmem_device_get(nvmem_np, NULL, NULL);
nvmem = __nvmem_device_get(nvmem_np, NULL);
of_node_put(nvmem_np);
if (IS_ERR(nvmem))
return ERR_CAST(nvmem);
@ -975,7 +1017,7 @@ struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id)
if (!cell_id)
return ERR_PTR(-EINVAL);
return nvmem_cell_get_from_list(cell_id);
return nvmem_cell_get_from_lookup(dev, cell_id);
}
EXPORT_SYMBOL_GPL(nvmem_cell_get);
@ -1405,6 +1447,41 @@ void nvmem_del_cell_table(struct nvmem_cell_table *table)
}
EXPORT_SYMBOL_GPL(nvmem_del_cell_table);
/**
* nvmem_add_cell_lookups() - register a list of cell lookup entries
*
* @entries: array of cell lookup entries
* @nentries: number of cell lookup entries in the array
*/
void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
{
int i;
mutex_lock(&nvmem_lookup_mutex);
for (i = 0; i < nentries; i++)
list_add_tail(&entries[i].node, &nvmem_lookup_list);
mutex_unlock(&nvmem_lookup_mutex);
}
EXPORT_SYMBOL_GPL(nvmem_add_cell_lookups);
/**
* nvmem_del_cell_lookups() - remove a list of previously added cell lookup
* entries
*
* @entries: array of cell lookup entries
* @nentries: number of cell lookup entries in the array
*/
void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
{
int i;
mutex_lock(&nvmem_lookup_mutex);
for (i = 0; i < nentries; i++)
list_del(&entries[i].node);
mutex_unlock(&nvmem_lookup_mutex);
}
EXPORT_SYMBOL_GPL(nvmem_del_cell_lookups);
/**
* nvmem_dev_name() - Get the name of a given nvmem device.
*

28
include/linux/nvmem-consumer.h
View File

@ -29,6 +29,24 @@ struct nvmem_cell_info {
unsigned int nbits;
};
/**
* struct nvmem_cell_lookup - cell lookup entry
*
* @nvmem_name: Name of the provider.
* @cell_name: Name of the nvmem cell as defined in the name field of
* struct nvmem_cell_info.
* @dev_id: Name of the consumer device that will be associated with
* this cell.
* @con_id: Connector id for this cell lookup.
*/
struct nvmem_cell_lookup {
const char *nvmem_name;
const char *cell_name;
const char *dev_id;
const char *con_id;
struct list_head node;
};
#if IS_ENABLED(CONFIG_NVMEM)
/* Cell based interface */
@ -57,6 +75,11 @@ int nvmem_device_cell_write(struct nvmem_device *nvmem,
const char *nvmem_dev_name(struct nvmem_device *nvmem);
void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries,
size_t nentries);
void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries,
size_t nentries);
#else
static inline struct nvmem_cell *nvmem_cell_get(struct device *dev,
@ -151,6 +174,11 @@ static inline const char *nvmem_dev_name(struct nvmem_device *nvmem)
return NULL;
}
static inline void
nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries) {}
static inline void
nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries) {}
#endif /* CONFIG_NVMEM */
#if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)