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SubjectRe: [PATCH 1/2] serdev: Add serdev_device_write subroutine
On Wed, Mar 15, 2017 at 7:18 AM, Rob Herring <robh@kernel.org> wrote:
> On Tue, Mar 14, 2017 at 8:48 AM, Andrey Smirnov
> <andrew.smirnov@gmail.com> wrote:
>> Add serdev_device_write() which is a blocking call allowing to transfer
>> arbitraty amount of data (potentially exceeding amount that
>> serdev_device_write_buf can process in a single call)
>>
>> Cc: cphealy@gmail.com
>> Cc: Guenter Roeck <linux@roeck-us.net>
>> Cc: linux-serial@vger.kernel.org
>> Cc: linux-kernel@vger.kernel.org
>> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
>> ---
>> drivers/tty/serdev/core.c | 37 +++++++++++++++++++++++++++++++++++++
>> include/linux/serdev.h | 23 +++++++++++++++++------
>> 2 files changed, 54 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
>> index f4c6c90..759e834 100644
>> --- a/drivers/tty/serdev/core.c
>> +++ b/drivers/tty/serdev/core.c
>> @@ -128,6 +128,41 @@ int serdev_device_write_buf(struct serdev_device *serdev,
>> }
>> EXPORT_SYMBOL_GPL(serdev_device_write_buf);
>>
>> +int serdev_device_write(struct serdev_device *serdev,
>> + const unsigned char *buf, size_t count)
>
> _write vs. _write_buf are not all that clear what the difference is.
> but I don't have a better name.
>

serdev_device_send?

> Perhaps a timeout param is needed? This could never complete if CTS
> remains deasserted.

Yeah, I think it is a good idea, I'll add that in v2.

>
>> +{
>> + int ret = count;
>> +
>> + if (serdev->ops->write_wakeup)
>> + return -EINVAL;
>> +
>> + mutex_lock(&serdev->write_lock);
>> +
>> + for (;;) {
>> + size_t chunk;
>> +
>> + reinit_completion(&serdev->write_wakeup);
>
> Perhaps write_comp instead as write_wakeup is already a function name.
>

OK, will do.

>> +
>> + chunk = serdev_device_write_buf(serdev, buf, count);
>> + if (chunk < 0) {
>> + ret = chunk;
>> + goto done;
>> + }
>> +
>> + buf += chunk;
>> + count -= chunk;
>> +
>> + if (!count)
>> + break;
>> +
>> + wait_for_completion(&serdev->write_wakeup);
>> + }
>> +done:
>> + mutex_unlock(&serdev->write_lock);
>> + return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(serdev_device_write);
>> +
>> void serdev_device_write_flush(struct serdev_device *serdev)
>> {
>> struct serdev_controller *ctrl = serdev->ctrl;
>> @@ -232,6 +267,8 @@ struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
>> serdev->dev.parent = &ctrl->dev;
>> serdev->dev.bus = &serdev_bus_type;
>> serdev->dev.type = &serdev_device_type;
>> + init_completion(&serdev->write_wakeup);
>> + mutex_init(&serdev->write_lock);
>> return serdev;
>> }
>> EXPORT_SYMBOL_GPL(serdev_device_alloc);
>> diff --git a/include/linux/serdev.h b/include/linux/serdev.h
>> index 5176cdc..8f7aa35 100644
>> --- a/include/linux/serdev.h
>> +++ b/include/linux/serdev.h
>> @@ -35,16 +35,19 @@ struct serdev_device_ops {
>>
>> /**
>> * struct serdev_device - Basic representation of an serdev device
>> - * @dev: Driver model representation of the device.
>> - * @nr: Device number on serdev bus.
>> - * @ctrl: serdev controller managing this device.
>> - * @ops: Device operations.
>> + * @dev: Driver model representation of the device.
>> + * @nr: Device number on serdev bus.
>> + * @ctrl: serdev controller managing this device.
>> + * @ops: Device operations.
>> + * @write_wakeup Completion used by serdev_device_write internally
>> */
>> struct serdev_device {
>> struct device dev;
>> int nr;
>> struct serdev_controller *ctrl;
>> const struct serdev_device_ops *ops;
>> + struct completion write_wakeup;
>> + struct mutex write_lock;
>> };
>>
>> static inline struct serdev_device *to_serdev_device(struct device *d)
>> @@ -162,10 +165,13 @@ static inline void serdev_controller_write_wakeup(struct serdev_controller *ctrl
>> {
>> struct serdev_device *serdev = ctrl->serdev;
>>
>> - if (!serdev || !serdev->ops->write_wakeup)
>> + if (!serdev)
>> return;
>>
>> - serdev->ops->write_wakeup(serdev);
>> + if (serdev->ops->write_wakeup)
>> + serdev->ops->write_wakeup(serdev);
>> + else
>> + complete(&serdev->write_wakeup);
>> }
>>
>> static inline int serdev_controller_receive_buf(struct serdev_controller *ctrl,
>> @@ -187,6 +193,7 @@ void serdev_device_close(struct serdev_device *);
>> unsigned int serdev_device_set_baudrate(struct serdev_device *, unsigned int);
>> void serdev_device_set_flow_control(struct serdev_device *, bool);
>> int serdev_device_write_buf(struct serdev_device *, const unsigned char *, size_t);
>> +int serdev_device_write(struct serdev_device *serdev, const unsigned char *buf, size_t count);
>
> Drop the param names to be consistent with the rest of the declarations.

OK, will do.

>
>> void serdev_device_write_flush(struct serdev_device *);
>> int serdev_device_write_room(struct serdev_device *);
>>
>> @@ -227,6 +234,10 @@ static inline int serdev_device_write_buf(struct serdev_device *sdev, const unsi
>> {
>> return -ENODEV;
>> }
>> +static inline int serdev_device_write(struct serdev_device *sdev, const unsigned char *buf, size_t count)
>> +{
>> + return -ENODEV;
>> +}
>> static inline void serdev_device_write_flush(struct serdev_device *sdev) {}
>> static inline int serdev_device_write_room(struct serdev_device *sdev)
>> {
>> --
>> 2.9.3
>>

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