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RIOT/drivers/include/periph/usbdev.h
Koen Zandberg 597f1d19aa
usbdev: Refactor to xmit API 
This API change refactors the usbdev API to supply buffers via the
usbdev_ep_xmit function. This changes from the usbdev_ep_ready call to allow
separate buffers per call. An usbdev_ep_buf_t pseudotype is available and must
be used when defining buffers used for endpoints to adhere to the DMA alignment
restrictions often required with usb peripherals.

Main advantage is that the usbdev peripherals no longer have to allocate
oversized buffers for the endpoint data, potentially saving multiple KiB
of unused buffer space. These allocations are now the responsibility of
the individual USB interfaces in the firmware
2021-11-16 11:21:07 +01:00

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/*
* Copyright (C) 2018 Koen Zandberg <koen@bergzand.net>
*
* This file is subject to the terms and conditions of the GNU Lesser General
* Public License v2.1. See the file LICENSE in the top level directory for
* more details.
*/
/**
* @defgroup drivers_periph_usbdev usbdev - USB Device Driver API
* @ingroup drivers_periph
* @brief This is a generic low-level USB driver interface
* @{
*
* # About
*
* usbdev specifies a common USB device API for low level USB interfaces. The
* interface is split in a definition for the USB interface hardware and for
* individual USB endpoints.
*
* # Design goals
*
* 1. Support for multiple instances on a single board
* 2. Interface optimized for MCU peripheral interfaces.
*
* # Details
*
* The driver interface is split in two separate parts. One part is a global USB
* device interface, the other is an endpoint control API.
*
* The usb device driver can manage parts of the USB interface itself such as
* the pull up resistor state or the USB speed.
*
* The endpoint control API manages a single endpoint. This allows for a modular
* approach where multiple USB functions/interfaces can be multiplexed over a
* single USB interface. Each interface can be implemented as a separate module.
* The interface handler does not have to care about the usb device itself or
* it's endpoint number. It can simply request an available endpoint from the
* usb device with the @ref usbdev_new_ep function.
*
* Each interface handler can request multiple endpoints from the usbdev device.
* It must supply the expected maximum endpoint transfer size and other
* properties of the endpoint. A pointer to an usbdev endpoint is returned if
* an endpoint fitting the requirements is available.
*
* Data transmission is done via the @ref usbdev_ep_xmit function. A buffer and
* length must be supplied. Received data from the host ends up at this buffer
* automatically by the low level drivers after reception. For reception the
* maximum expected transfer length must be supplied, equal to the maximum
* endpoint transfer size. The data received can be less than this.
*
* For transmitting data back to the host, a similar approach is used. The data
* to be transmitted is supplied as buffer and the @ref usbdev_ep_xmit function
* is called with the buffer and the size of the data.
*
* To ensure that the data buffers adhere to the restrictions of the low level
* USB peripheral memory interface, the specific @ref usbdev_ep_buf_t data type
* must be used. It behaves as a regular `uint8_t` byte buffer, but is
* instantiated with the attributes to ensure that the low level DMA interface
* can use it.
*
* A callback function is required for signalling events from the driver. The
* @ref USBDEV_EVENT_ESR is special in that it indicates that the USB peripheral
* had an interrupt that needs to be serviced in a non-interrupt context. This
* requires the usbdev_esr function to be called. In the case that the event is
* signalled via the @ref usbdev_t::epcb callback, the @ref usbdev_ep_esr
* should be called to service the endpoint specific events from the
* peripheral.
*
* @file
* @brief Definitions low-level USB driver interface
*
* @author Koen Zandberg <koen@bergzand.net>
*/
#ifndef PERIPH_USBDEV_H
#define PERIPH_USBDEV_H
#include <stdint.h>
#include <stddef.h>
#include "assert.h"
#include "periph_cpu.h"
#include "usb.h"
#include "usb/usbopt.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief usbdev_t forward declaration
*/
typedef struct usbdev usbdev_t;
/**
* @brief usbdev_ep_t forward declaration
*/
typedef struct usbdev_ep usbdev_ep_t;
/**
* @brief USBDEV endpoint buffer CPU-specific requirements
*
* Can be overridden by periph_cpu if needed by the USB peripheral DMA.
*/
#ifndef USBDEV_CPU_DMA_REQUIREMENTS
#define USBDEV_CPU_DMA_REQUIREMENTS
#endif
/**
* @brief Instantiation type for usbdev endpoint buffers
*
* Functions passing around pointers to these buffers can still use `uint8_t`
* for the argument type.
*
* Example usage:
*
* ```
* usbdev_ep_buf_t buffer[64];
* ```
*
* @note This is a define and not a typedef so that the above works. With a
* typedef it would instantiate an array of aligned uint8_t and not an aligned
* array of uint8_t (assuming the requirement is alignment).
*/
#define usbdev_ep_buf_t USBDEV_CPU_DMA_REQUIREMENTS uint8_t
/**
* @brief Number of USB IN and OUT endpoints allocated
*
* Configures the number of endpoints allocated. An equal number of IN and OUT
* endpoints are allocated
*/
#ifndef USBDEV_NUM_ENDPOINTS
#define USBDEV_NUM_ENDPOINTS 8
#endif
/**
* @brief List of event types that can be send from the device driver to the
* upper layer
*/
typedef enum {
/**
* @brief Driver needs it's ESR (event service routine) handled
*/
USBDEV_EVENT_ESR = 1,
/**
* @brief Host connection detected
*
* A host has connected to the device. Detection should happen by detecting
* the USB power, but other detection mechanisms might be used.
*/
USBDEV_EVENT_HOST_CONNECT,
/**
* @brief Host disconnected from the device
*
* Similar to @ref USBDEV_EVENT_HOST_CONNECT, except that the host
* disconnected instead.
*/
USBDEV_EVENT_HOST_DISCONNECT,
/**
* @brief Line reset occurred
*
* A line reset is a host initiated USB reset to the peripheral
*
* The peripheral driver must clears the following settings before
* emitting this event:
* - Device address
* - Endpoint configuration, including stall settings
*/
USBDEV_EVENT_RESET,
/**
* @brief Start of Frame received
*
* A Start of Frame (SoF) packet is received from the host.
*/
USBDEV_EVENT_SOF,
/**
* @brief USB suspend condition active
*/
USBDEV_EVENT_SUSPEND,
/**
* @brief USB suspend condition no longer active
*/
USBDEV_EVENT_RESUME,
/**
* @brief Transaction completed event.
*
* An endpoint must emit this event after a transaction with the host
* occurred to indicate that the data in the buffer is used or new
* depending on the endpoint direction
*/
USBDEV_EVENT_TR_COMPLETE,
/**
* @brief Transaction stall event.
*
* An endpoint should emit this event after a stall reply has been
* transmitted to the host
*/
USBDEV_EVENT_TR_STALL,
/**
* @brief Transaction fail event.
*
* @deprecated This event is deprecated as only a limited number of devices
* implement and doesn't offer value for upper layer code. This
* event will be removed after the 2022.07 release.
*
* An endpoint should emit this event after a nack reply to the host.
*/
USBDEV_EVENT_TR_FAIL,
/* expand list if required */
} usbdev_event_t;
/**
* @brief Event callback for signaling usbdev event to upper layers
*
* @param[in] usbdev usbdev context
* @param[in] event type of the event
*/
typedef void (*usbdev_event_cb_t)(usbdev_t *usbdev, usbdev_event_t event);
/**
* @brief Event callback for signaling endpoint events to upper layers
*
* @param[in] ep usbdev endpoint context
* @param[in] event type of the event
*/
typedef void (*usbdev_ep_event_cb_t)(usbdev_ep_t *ep,
usbdev_event_t event);
/**
* @brief usbdev device descriptor
*/
struct usbdev {
const struct usbdev_driver *driver; /**< usbdev driver struct */
usbdev_event_cb_t cb; /**< Event callback supplied by
* upper layer */
usbdev_ep_event_cb_t epcb; /**< Endpoint event callback for
* upper layer */
void *context; /**< Ptr to the thread context */
};
/**
* @brief usbdev endpoint descriptor
*/
struct usbdev_ep {
usbdev_t *dev; /**< USB device this endpoint belongs to */
size_t len; /**< Endpoint configured max transfer size in bytes */
usb_ep_dir_t dir; /**< Endpoint direction */
usb_ep_type_t type; /**< Endpoint type */
uint8_t num; /**< Endpoint number */
};
/**
* @brief usbdev driver functions
*
* Helpers (such as @ref usbdev_init) are provided and should be used instead.
* Directly calling these functions is not recommended.
*/
typedef struct usbdev_driver {
/**
* @brief Initialize the USB peripheral device
*
* This initializes the USB device but must not enable the USB pull up.
*
* @param[in] dev USB device descriptor
*/
void (*init)(usbdev_t *usbdev);
/**
* @brief Retrieve an USB endpoint of the specified type
*
* requesting an endpoint of @ref USB_EP_TYPE_CONTROL must always return
* endpoint 0 of the specified direction
*
* @param[in] dev USB device descriptor
* @param[in] type USB endpoint type
* @param[in] dir USB endpoint direction
* @param[in] size USB endpoint buffer size
*
* @return ptr to the new USB endpoint descriptor
* @return NULL on error
*/
usbdev_ep_t *(*new_ep)(usbdev_t *dev, usb_ep_type_t type, usb_ep_dir_t dir, size_t size);
/**
* @brief Get an option value from a given usb device
*
* @param[in] dev USB device descriptor
* @param[in] opt option type
* @param[out] value pointer to store the option's value in
* @param[in] max_len maximal amount of byte that fit into @p value
*
* @return number of bytes written to @p value
* @return `< 0` on error 0
*/
int (*get)(usbdev_t *usbdev, usbopt_t opt,
void *value, size_t max_len);
/**
* @brief Set an option value for a given usb device
*
* @param[in] dev USB device descriptor
* @param[in] opt option type
* @param[in] value value to set
* @param[in] value_len the length of @p value
*
* @return number of bytes used from @p value
* @return `< 0` on error
*/
int (*set)(usbdev_t *usbdev, usbopt_t opt,
const void *value, size_t value_len);
/**
* @brief a driver's user-space event service handler
*
* This function will be called from a USB stack's loop when being
* notified by usbdev_event_isr.
*
* @param[in] dev USB device descriptor
*/
void (*esr)(usbdev_t *dev);
/**
* @brief Initialize the USB endpoint
*
* This initializes the USB endpoint with the settings from the
* @ref usbdev_ep.
*
* @param[in] ep USB endpoint descriptor
*/
void (*ep_init)(usbdev_ep_t *ep);
/**
* @brief Get an option value from a given usb device endpoint
*
* @param[in] ep USB endpoint descriptor
* @param[in] opt option type
* @param[out] value pointer to store the option's value in
* @param[in] max_len maximum number of byte that fit into @p value
*
* @return number of bytes written to @p value
* @return `< 0` on error
*/
int (*ep_get)(usbdev_ep_t *ep, usbopt_ep_t opt,
void *value, size_t max_len);
/**
* @brief Set an option value for a given usb device endpoint
*
* @param[in] ep USB endpoint descriptor
* @param[in] opt option type
* @param[in] value pointer to the value
* @param[in] value_len the length of @p value
*
* @return number of bytes used from @p value
* @return `< 0` on error
*/
int (*ep_set)(usbdev_ep_t *ep, usbopt_ep_t opt,
const void *value, size_t value_len);
/**
* @brief an endpoint's user-space event handler
*
* Must be called in response to an @ref USBDEV_EVENT_ESR event in
* userspace context.
*
* @param[in] ep USB endpoint descriptor to service
*/
void (*ep_esr)(usbdev_ep_t *ep);
/**
* @brief Transmit a data buffer
*
* Ownership of the @p buf is transferred to the usbdev device after calling
* this. Do not modify (or unallocate) the buffer between calling this and
* when it is released via the @ref USBDEV_EVENT_TR_COMPLETE event.
*
* This clears the stall setting in the endpoint if that is enabled.
*
* @note The @p buf passed here must have been declared as
* @ref usbdev_ep_buf_t before so that DMA restrictions are applied to it
*
* @param[in] ep USB endpoint descriptor
* @param[inout] buf Buffer with the data to transfer
* @param[in] len (Max) Length of the data to transfer
*/
int (*xmit)(usbdev_ep_t *ep, uint8_t *buf, size_t len);
} usbdev_driver_t;
/**
* @brief Low level USB peripheral driver initialization
*
* This function prepares all usbdev peripherals available for initialization
*/
void usbdev_init_lowlevel(void);
/**
* @brief Retrieve usbdev context from the peripheral
*
* @param num usbdev peripheral number to retrieve
*
* @returns the usbdev context at index @p num
*/
usbdev_t *usbdev_get_ctx(unsigned num);
/**
* @brief Initialize the USB peripheral device
*
* @see @ref usbdev_driver_t::init
*
* @pre `(dev != NULL)`
*
* @param dev usb device to initialize
*/
static inline void usbdev_init(usbdev_t *dev)
{
assert(dev);
dev->driver->init(dev);
}
/**
* @brief Retrieve an USB endpoint of the specified type
*
* @see @ref usbdev_driver_t::new_ep
*
* @pre `(dev != NULL)`
*
* @param[in] dev USB device descriptor
* @param[in] type USB endpoint type
* @param[in] dir USB endpoint direction
* @param[in] size Maximum USB endpoint buffer size used
*
* @return ptr to the new USB endpoint descriptor
* @return NULL on error
*/
static inline usbdev_ep_t * usbdev_new_ep(usbdev_t *dev, usb_ep_type_t type,
usb_ep_dir_t dir, size_t size)
{
assert(dev);
return dev->driver->new_ep(dev, type, dir, size);
}
/**
* @brief Get an option value from a given usb device
*
* @see @ref usbdev_driver_t::get
*
* @pre `(dev != NULL)`
*
* @param[in] dev USB device descriptor
* @param[in] opt option type
* @param[out] value pointer to store the option's value in
* @param[in] max_len maximal amount of byte that fit into @p value
*
* @return number of bytes written to @p value
* @return `< 0` on error 0
*/
static inline int usbdev_get(usbdev_t *dev, usbopt_t opt,
void *value, size_t max_len)
{
assert(dev);
return dev->driver->get(dev, opt, value, max_len);
}
/**
* @brief Set an option value for a given usb device
*
* @see @ref usbdev_driver_t::set
*
* @pre `(dev != NULL)`
*
* @param[in] dev USB device descriptor
* @param[in] opt option type
* @param[in] value value to set
* @param[in] value_len the length of @p value
*
* @return number of bytes used from @p value
* @return `< 0` on error
*/
static inline int usbdev_set(usbdev_t *dev, usbopt_t opt,
const void *value, size_t value_len)
{
assert(dev);
return dev->driver->set(dev, opt, value, value_len);
}
/**
* @brief a driver's user-space event service handler
*
* @see @ref usbdev_driver_t::esr
*
* @pre `(dev != NULL)`
*
* @param[in] dev USB device descriptor
*/
static inline void usbdev_esr(usbdev_t *dev)
{
assert(dev);
dev->driver->esr(dev);
}
/**
* @brief Initialize the USB endpoint
*
* @see @ref usbdev_driver_t::ep_init
*
* @pre `(ep != NULL)`
* @pre `(ep->dev != NULL)`
*
* @param[in] ep USB endpoint descriptor
*/
static inline void usbdev_ep_init(usbdev_ep_t *ep)
{
assert(ep);
assert(ep->dev);
ep->dev->driver->ep_init(ep);
}
/**
* @brief Get an option value from a given usb device endpoint
*
* @see @ref usbdev_driver_t::ep_get
*
* @pre `(ep != NULL)`
* @pre `(ep->dev != NULL)`
*
* @param[in] ep USB endpoint descriptor
* @param[in] opt option type
* @param[out] value pointer to store the option's value in
* @param[in] max_len maximum number of byte that fit into @p value
*
* @return number of bytes written to @p value
* @return `< 0` on error
*/
static inline int usbdev_ep_get(usbdev_ep_t *ep, usbopt_ep_t opt,
void *value, size_t max_len)
{
assert(ep);
assert(ep->dev);
return ep->dev->driver->ep_get(ep, opt, value, max_len);
}
/**
* @brief Set an option value for a given usb device endpoint
*
* @see @ref usbdev_driver_t::ep_set
*
* @pre `(ep != NULL)`
* @pre `(ep->dev != NULL)`
*
* @param[in] ep USB endpoint descriptor
* @param[in] opt option type
* @param[in] value pointer to the value
* @param[in] value_len the length of @p value
*
* @return number of bytes used from @p value
* @return `< 0` on error
*/
static inline int usbdev_ep_set(usbdev_ep_t *ep, usbopt_ep_t opt,
const void *value, size_t value_len)
{
assert(ep);
assert(ep->dev);
return ep->dev->driver->ep_set(ep, opt, value, value_len);
}
/**
* @brief an endpoint's user-space event handler
*
* @see @ref usbdev_driver_t::ep_esr
*
* @pre `(ep != NULL)`
* @pre `(ep->dev != NULL)`
*
* @param[in] ep USB endpoint descriptor to service
*/
static inline void usbdev_ep_esr(usbdev_ep_t *ep)
{
assert(ep);
assert(ep->dev);
ep->dev->driver->ep_esr(ep);
}
/**
* @brief Submit a buffer for a USB endpoint transmission
*
* When dealing with an OUT type endpoint, @p len must be the maximum allowed
* transfer size for the endpoint. The host is allowed to transfer fewer bytes
* than @p len.
*
* @see @ref usbdev_driver_t::xmit
*
* @pre `(ep != NULL)`
* @pre `(ep->dev != NULL)`
*
* @param[in] ep USB endpoint descriptor
* @param[inout] buf Buffer to submit for transmission
* @param[in] len length of the buffer in bytes to be transmitted or received
*/
static inline int usbdev_ep_xmit(usbdev_ep_t *ep, uint8_t *buf, size_t len)
{
assert(ep);
assert(ep->dev);
return ep->dev->driver->xmit(ep, buf, len);
}
#ifdef __cplusplus
}
#endif
#endif /* PERIPH_USBDEV_H */
/** @} */
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