| /* The industrial I/O core - generic ring buffer interfaces. |
| * |
| * Copyright (c) 2008 Jonathan Cameron |
| * |
| * This program is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 as published by |
| * the Free Software Foundation. |
| */ |
| |
| #ifndef _IIO_RING_GENERIC_H_ |
| #define _IIO_RING_GENERIC_H_ |
| #include "iio.h" |
| |
| #ifdef CONFIG_IIO_RING_BUFFER |
| |
| struct iio_ring_buffer; |
| |
| /** |
| * struct iio_ring_access_funcs - access functions for ring buffers. |
| * @mark_in_use: reference counting, typically to prevent module removal |
| * @unmark_in_use: reduce reference count when no longer using ring buffer |
| * @store_to: actually store stuff to the ring buffer |
| * @read_last: get the last element stored |
| * @read_first_n: try to get a specified number of elements (must exist) |
| * @mark_param_change: notify ring that some relevant parameter has changed |
| * Often this means the underlying storage may need to |
| * change. |
| * @request_update: if a parameter change has been marked, update underlying |
| * storage. |
| * @get_bytes_per_datum:get current bytes per datum |
| * @set_bytes_per_datum:set number of bytes per datum |
| * @get_length: get number of datums in ring |
| * @set_length: set number of datums in ring |
| * @is_enabled: query if ring is currently being used |
| * @enable: enable the ring |
| * |
| * The purpose of this structure is to make the ring buffer element |
| * modular as event for a given driver, different usecases may require |
| * different ring designs (space efficiency vs speed for example). |
| * |
| * It is worth noting that a given ring implementation may only support a small |
| * proportion of these functions. The core code 'should' cope fine with any of |
| * them not existing. |
| **/ |
| struct iio_ring_access_funcs { |
| void (*mark_in_use)(struct iio_ring_buffer *ring); |
| void (*unmark_in_use)(struct iio_ring_buffer *ring); |
| |
| int (*store_to)(struct iio_ring_buffer *ring, u8 *data, s64 timestamp); |
| int (*read_last)(struct iio_ring_buffer *ring, u8 *data); |
| int (*read_first_n)(struct iio_ring_buffer *ring, |
| size_t n, |
| char __user *buf); |
| |
| int (*mark_param_change)(struct iio_ring_buffer *ring); |
| int (*request_update)(struct iio_ring_buffer *ring); |
| |
| int (*get_bytes_per_datum)(struct iio_ring_buffer *ring); |
| int (*set_bytes_per_datum)(struct iio_ring_buffer *ring, size_t bpd); |
| int (*get_length)(struct iio_ring_buffer *ring); |
| int (*set_length)(struct iio_ring_buffer *ring, int length); |
| |
| int (*is_enabled)(struct iio_ring_buffer *ring); |
| int (*enable)(struct iio_ring_buffer *ring); |
| }; |
| |
| struct iio_ring_setup_ops { |
| int (*preenable)(struct iio_dev *); |
| int (*postenable)(struct iio_dev *); |
| int (*predisable)(struct iio_dev *); |
| int (*postdisable)(struct iio_dev *); |
| }; |
| |
| /** |
| * struct iio_ring_buffer - general ring buffer structure |
| * @dev: ring buffer device struct |
| * @indio_dev: industrial I/O device structure |
| * @owner: module that owns the ring buffer (for ref counting) |
| * @length: [DEVICE] number of datums in ring |
| * @bytes_per_datum: [DEVICE] size of individual datum including timestamp |
| * @bpe: [DEVICE] size of individual channel value |
| * @scan_el_attrs: [DRIVER] control of scan elements if that scan mode |
| * control method is used |
| * @scan_count: [INTERN] the number of elements in the current scan mode |
| * @scan_mask: [INTERN] bitmask used in masking scan mode elements |
| * @scan_timestamp: [INTERN] does the scan mode include a timestamp |
| * @access_handler: [INTERN] chrdev access handling |
| * @access: [DRIVER] ring access functions associated with the |
| * implementation. |
| * @preenable: [DRIVER] function to run prior to marking ring enabled |
| * @postenable: [DRIVER] function to run after marking ring enabled |
| * @predisable: [DRIVER] function to run prior to marking ring disabled |
| * @postdisable: [DRIVER] function to run after marking ring disabled |
| **/ |
| struct iio_ring_buffer { |
| struct device dev; |
| struct iio_dev *indio_dev; |
| struct module *owner; |
| int length; |
| int bytes_per_datum; |
| int bpe; |
| struct attribute_group *scan_el_attrs; |
| int scan_count; |
| unsigned long scan_mask; |
| bool scan_timestamp; |
| struct iio_handler access_handler; |
| const struct iio_ring_access_funcs *access; |
| const struct iio_ring_setup_ops *setup_ops; |
| struct list_head scan_el_dev_attr_list; |
| |
| wait_queue_head_t pollq; |
| bool stufftoread; |
| }; |
| |
| /** |
| * iio_ring_buffer_init() - Initialize the buffer structure |
| * @ring: buffer to be initialized |
| * @dev_info: the iio device the buffer is assocated with |
| **/ |
| void iio_ring_buffer_init(struct iio_ring_buffer *ring, |
| struct iio_dev *dev_info); |
| |
| /** |
| * __iio_update_ring_buffer() - update common elements of ring buffers |
| * @ring: ring buffer that is the event source |
| * @bytes_per_datum: size of individual datum including timestamp |
| * @length: number of datums in ring |
| **/ |
| static inline void __iio_update_ring_buffer(struct iio_ring_buffer *ring, |
| int bytes_per_datum, int length) |
| { |
| ring->bytes_per_datum = bytes_per_datum; |
| ring->length = length; |
| } |
| |
| /* |
| * These are mainly provided to allow for a change of implementation if a device |
| * has a large number of scan elements |
| */ |
| #define IIO_MAX_SCAN_LENGTH 31 |
| |
| /* note 0 used as error indicator as it doesn't make sense. */ |
| static inline u32 iio_scan_mask_match(u32 *av_masks, u32 mask) |
| { |
| while (*av_masks) { |
| if (!(~*av_masks & mask)) |
| return *av_masks; |
| av_masks++; |
| } |
| return 0; |
| } |
| |
| static inline int iio_scan_mask_query(struct iio_ring_buffer *ring, int bit) |
| { |
| struct iio_dev *dev_info = ring->indio_dev; |
| u32 mask; |
| |
| if (bit > IIO_MAX_SCAN_LENGTH) |
| return -EINVAL; |
| |
| if (!ring->scan_mask) |
| return 0; |
| |
| if (dev_info->available_scan_masks) |
| mask = iio_scan_mask_match(dev_info->available_scan_masks, |
| ring->scan_mask); |
| else |
| mask = ring->scan_mask; |
| |
| if (!mask) |
| return -EINVAL; |
| |
| return !!(mask & (1 << bit)); |
| }; |
| |
| /** |
| * iio_scan_mask_set() - set particular bit in the scan mask |
| * @ring: the ring buffer whose scan mask we are interested in |
| * @bit: the bit to be set. |
| **/ |
| static inline int iio_scan_mask_set(struct iio_ring_buffer *ring, int bit) |
| { |
| struct iio_dev *dev_info = ring->indio_dev; |
| u32 mask; |
| u32 trialmask = ring->scan_mask | (1 << bit); |
| |
| if (bit > IIO_MAX_SCAN_LENGTH) |
| return -EINVAL; |
| if (dev_info->available_scan_masks) { |
| mask = iio_scan_mask_match(dev_info->available_scan_masks, |
| trialmask); |
| if (!mask) |
| return -EINVAL; |
| } |
| ring->scan_mask = trialmask; |
| ring->scan_count++; |
| |
| return 0; |
| }; |
| |
| /** |
| * iio_put_ring_buffer() - notify done with buffer |
| * @ring: the buffer we are done with. |
| **/ |
| static inline void iio_put_ring_buffer(struct iio_ring_buffer *ring) |
| { |
| put_device(&ring->dev); |
| }; |
| |
| #define to_iio_ring_buffer(d) \ |
| container_of(d, struct iio_ring_buffer, dev) |
| |
| /** |
| * iio_ring_buffer_register_ex() - register the buffer with IIO core |
| * @ring: the buffer to be registered |
| * @id: the id of the buffer (typically 0) |
| **/ |
| int iio_ring_buffer_register_ex(struct iio_ring_buffer *ring, int id, |
| const struct iio_chan_spec *channels, |
| int num_channels); |
| |
| void iio_ring_access_release(struct device *dev); |
| |
| /** |
| * iio_ring_buffer_unregister() - unregister the buffer from IIO core |
| * @ring: the buffer to be unregistered |
| **/ |
| void iio_ring_buffer_unregister(struct iio_ring_buffer *ring); |
| |
| /** |
| * iio_read_ring_length() - attr func to get number of datums in the buffer |
| **/ |
| ssize_t iio_read_ring_length(struct device *dev, |
| struct device_attribute *attr, |
| char *buf); |
| /** |
| * iio_write_ring_length() - attr func to set number of datums in the buffer |
| **/ |
| ssize_t iio_write_ring_length(struct device *dev, |
| struct device_attribute *attr, |
| const char *buf, |
| size_t len); |
| /** |
| * iio_read_ring_bytes_per_datum() - attr for number of bytes in whole datum |
| **/ |
| ssize_t iio_read_ring_bytes_per_datum(struct device *dev, |
| struct device_attribute *attr, |
| char *buf); |
| /** |
| * iio_store_ring_enable() - attr to turn the buffer on |
| **/ |
| ssize_t iio_store_ring_enable(struct device *dev, |
| struct device_attribute *attr, |
| const char *buf, |
| size_t len); |
| /** |
| * iio_show_ring_enable() - attr to see if the buffer is on |
| **/ |
| ssize_t iio_show_ring_enable(struct device *dev, |
| struct device_attribute *attr, |
| char *buf); |
| #define IIO_RING_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \ |
| iio_read_ring_length, \ |
| iio_write_ring_length) |
| #define IIO_RING_BYTES_PER_DATUM_ATTR DEVICE_ATTR(bytes_per_datum, S_IRUGO | S_IWUSR, \ |
| iio_read_ring_bytes_per_datum, NULL) |
| #define IIO_RING_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \ |
| iio_show_ring_enable, \ |
| iio_store_ring_enable) |
| |
| int iio_sw_ring_preenable(struct iio_dev *indio_dev); |
| |
| #else /* CONFIG_IIO_RING_BUFFER */ |
| |
| static inline int iio_ring_buffer_register_ex(struct iio_ring_buffer *ring, |
| int id, |
| struct iio_chan_spec *channels, |
| int num_channels) |
| { |
| return 0; |
| } |
| |
| static inline void iio_ring_buffer_unregister(struct iio_ring_buffer *ring) |
| {}; |
| |
| #endif /* CONFIG_IIO_RING_BUFFER */ |
| |
| #endif /* _IIO_RING_GENERIC_H_ */ |