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Message-ID: <CAMRc=MdnSHY1ah4X3Bu55HvZcOQHxPHaFudidDA4mEOW9ZzeEg@mail.gmail.com>
Date: Mon, 10 Sep 2018 10:17:48 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc: "David S . Miller" <davem@...emloft.net>,
Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Arnd Bergmann <arnd@...db.de>,
Jonathan Corbet <corbet@....net>, Sekhar Nori <nsekhar@...com>,
Kevin Hilman <khilman@...nel.org>,
David Lechner <david@...hnology.com>,
Boris Brezillon <boris.brezillon@...tlin.com>,
Andrew Lunn <andrew@...n.ch>, Alban Bedel <albeu@...e.fr>,
Maxime Ripard <maxime.ripard@...tlin.com>,
Chen-Yu Tsai <wens@...e.org>,
linux-doc <linux-doc@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux ARM <linux-arm-kernel@...ts.infradead.org>,
Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH v2 13/16] nvmem: add support for cell lookups from machine code
2018-09-10 9:32 GMT+02:00 Srinivas Kandagatla <srinivas.kandagatla@...aro.org>:
>
>
> On 07/09/18 11:07, Bartosz Golaszewski wrote:
>>
>> From: Bartosz Golaszewski <bgolaszewski@...libre.com>
>>
>> Add a way for machine code users to associate devices with nvmem cells.
>>
>> Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
>> ---
>> drivers/nvmem/core.c | 143 +++++++++++++++++++++++++++-------
>> include/linux/nvmem-machine.h | 16 ++++
>> 2 files changed, 132 insertions(+), 27 deletions(-)
>>
>> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
>> index da7a9d5beb33..9e2f9c993a07 100644
>> --- a/drivers/nvmem/core.c
>> +++ b/drivers/nvmem/core.c
>> @@ -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);
>> +
>> static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
>> #ifdef CONFIG_DEBUG_LOCK_ALLOC
>> @@ -285,6 +288,18 @@ 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);
>> +}
>> +
>
> This is removed and added back in same patch, you should consider
> positioning the caller if possible to avoid any un-necessary changes.
>
>> static void nvmem_cell_drop(struct nvmem_cell *cell)
>> {
>> mutex_lock(&nvmem_mutex);
>> @@ -421,6 +436,21 @@ nvmem_find_cell_by_index(struct nvmem_device *nvmem,
>> int index)
>> return cell;
>> }
>> +static struct nvmem_cell *
>> +nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
>> +{
>> + struct nvmem_cell *cell = ERR_PTR(-ENOENT);
>> + struct nvmem_cell_lookup *lookup;
>> + struct nvmem_device *nvmem;
>> + const char *dev_id;
>> +
>> + 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)
>> + goto out;
>
> Here nvmem refcount has already increased, you should probably fix this!
Indeed.
>>
>> + }
>> + }
>> +
>> +out:
>> + mutex_unlock(&nvmem_lookup_mutex);
>> + return cell;
>> +}
>
>
> ...
>
>> diff --git a/include/linux/nvmem-machine.h b/include/linux/nvmem-machine.h
>
>
> Should be part of nvmem-consumer.h.
>
If anything, this should probably go to nvmem-provider.h. But I like
the gpiolib way of putting machine-specific code into a separate
header. Most systems are not interested in these definitions anyway.
IMO this is a valid use case where creating a new header makes sense.
Bart
>> index 1e199dfaacab..7859c08934d5 100644
>> --- a/include/linux/nvmem-machine.h
>> +++ b/include/linux/nvmem-machine.h
>> @@ -26,16 +26,32 @@ struct nvmem_cell_table {
>> struct list_head node;
>> };
>> +struct nvmem_cell_lookup {
>> + const char *nvmem_name;
>> + const char *cell_name;
>> + const char *dev_id;
>> + const char *con_id;
>> + struct list_head node;
>> +};
>
>
> Consider adding kerneldoc to this structure.
>
>
>> +
>> #if IS_ENABLED(CONFIG_NVMEM)
>> void nvmem_add_cell_table(struct nvmem_cell_table *table);
>> void nvmem_del_cell_table(struct nvmem_cell_table *table);
>> +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 /* CONFIG_NVMEM */
>> static inline void nvmem_add_cell_table(struct nvmem_cell_table
>> *table) {}
>> static inline void nvmem_del_cell_table(struct nvmem_cell_table *table)
>> {}
>> +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 */
>> #endif /* ifndef _LINUX_NVMEM_MACHINE_H */
>>
>
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