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freebsd-dev/sys/dev/usb/usb_core.h
Hans Petter Selasky 0eb8d46232 Improve USB polling mode by not locking any mutexes, asserting any 
mutexes or using any callouts when active.

Trying to lock a mutex when KDB is active or the scheduler is stopped
can result in infinite wait loops. The same goes for calling callout
related functions which in turn lock mutexes.

If the USB controller at which a USB keyboard is connected is idle
when KDB is entered, polling the USB keyboard via USB will always
succeed. Else polling may fail depending on which state the USB
subsystem and USB interrupt handler is in. This is unavoidable unless
KDB can wait for USB interrupt threads to complete before stalling the
CPU(s).

Tested by:	Bruce Evans <bde@freebsd.org>
MFC after:	4 weeks
2016-09-14 12:07:34 +00:00

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/* $FreeBSD$ */
/*-
* Copyright (c) 2008 Hans Petter Selasky. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Including this file is mandatory for all USB related c-files in the kernel.
*/
#ifndef _USB_CORE_H_
#define _USB_CORE_H_
/*
* The following macro will tell if an USB transfer is currently
* receiving or transferring data.
*/
#define USB_GET_DATA_ISREAD(xfer) ((xfer)->flags_int.usb_mode == \
USB_MODE_DEVICE ? (((xfer)->endpointno & UE_DIR_IN) ? 0 : 1) : \
(((xfer)->endpointno & UE_DIR_IN) ? 1 : 0))
/* locking wrappers for BUS lock */
#define USB_BUS_LOCK(_b) USB_MTX_LOCK(&(_b)->bus_mtx)
#define USB_BUS_UNLOCK(_b) USB_MTX_UNLOCK(&(_b)->bus_mtx)
#define USB_BUS_LOCK_ASSERT(_b, _t) USB_MTX_ASSERT(&(_b)->bus_mtx, _t)
/* locking wrappers for BUS spin lock */
#define USB_BUS_SPIN_LOCK(_b) USB_MTX_LOCK_SPIN(&(_b)->bus_spin_lock)
#define USB_BUS_SPIN_UNLOCK(_b) USB_MTX_UNLOCK_SPIN(&(_b)->bus_spin_lock)
#define USB_BUS_SPIN_LOCK_ASSERT(_b, _t) USB_MTX_ASSERT(&(_b)->bus_spin_lock, _t)
/* locking wrappers for XFER lock */
#define USB_XFER_LOCK(_x) USB_MTX_LOCK((_x)->xroot->xfer_mtx)
#define USB_XFER_UNLOCK(_x) USB_MTX_UNLOCK((_x)->xroot->xfer_mtx)
#define USB_XFER_LOCK_ASSERT(_x, _t) USB_MTX_ASSERT((_x)->xroot->xfer_mtx, _t)
/* helper for converting pointers to integers */
#define USB_P2U(ptr) \
(((const uint8_t *)(ptr)) - ((const uint8_t *)0))
/* helper for computing offsets */
#define USB_ADD_BYTES(ptr,size) \
((void *)(USB_P2U(ptr) + (size)))
/* debug macro */
#define USB_ASSERT KASSERT
/* structure prototypes */
struct file;
struct usb_bus;
struct usb_device;
struct usb_device_request;
struct usb_page;
struct usb_page_cache;
struct usb_xfer;
struct usb_xfer_root;
struct usb_string_lang;
/* typedefs */
/* structures */
/*
* The following structure defines a set of internal USB transfer
* flags.
*/
struct usb_xfer_flags_int {
enum usb_hc_mode usb_mode; /* shadow copy of "udev->usb_mode" */
uint16_t control_rem; /* remainder in bytes */
uint8_t open:1; /* set if USB pipe has been opened */
uint8_t transferring:1; /* set if an USB transfer is in
* progress */
uint8_t did_dma_delay:1; /* set if we waited for HW DMA */
uint8_t did_close:1; /* set if we closed the USB transfer */
uint8_t draining:1; /* set if we are draining an USB
* transfer */
uint8_t started:1; /* keeps track of started or stopped */
uint8_t bandwidth_reclaimed:1;
uint8_t control_xfr:1; /* set if control transfer */
uint8_t control_hdr:1; /* set if control header should be
* sent */
uint8_t control_act:1; /* set if control transfer is active */
uint8_t control_stall:1; /* set if control transfer should be stalled */
uint8_t control_did_data:1; /* set if control DATA has been transferred */
uint8_t short_frames_ok:1; /* filtered version */
uint8_t short_xfer_ok:1; /* filtered version */
#if USB_HAVE_BUSDMA
uint8_t bdma_enable:1; /* filtered version (only set if
* hardware supports DMA) */
uint8_t bdma_no_post_sync:1; /* set if the USB callback wrapper
* should not do the BUS-DMA post sync
* operation */
uint8_t bdma_setup:1; /* set if BUS-DMA has been setup */
#endif
uint8_t isochronous_xfr:1; /* set if isochronous transfer */
uint8_t curr_dma_set:1; /* used by USB HC/DC driver */
uint8_t can_cancel_immed:1; /* set if USB transfer can be
* cancelled immediately */
uint8_t doing_callback:1; /* set if executing the callback */
uint8_t maxp_was_clamped:1; /* set if the max packet size
* was outside its allowed range */
};
/*
* The following structure defines an USB transfer.
*/
struct usb_xfer {
struct usb_callout timeout_handle;
TAILQ_ENTRY(usb_xfer) wait_entry; /* used at various places */
struct usb_page_cache *buf_fixup; /* fixup buffer(s) */
struct usb_xfer_queue *wait_queue; /* pointer to queue that we
* are waiting on */
struct usb_page *dma_page_ptr;
struct usb_endpoint *endpoint; /* our USB endpoint */
struct usb_xfer_root *xroot; /* used by HC driver */
void *qh_start[2]; /* used by HC driver */
void *td_start[2]; /* used by HC driver */
void *td_transfer_first; /* used by HC driver */
void *td_transfer_last; /* used by HC driver */
void *td_transfer_cache; /* used by HC driver */
void *priv_sc; /* device driver data pointer 1 */
void *priv_fifo; /* device driver data pointer 2 */
void *local_buffer;
usb_frlength_t *frlengths;
struct usb_page_cache *frbuffers;
usb_callback_t *callback;
usb_frlength_t max_hc_frame_size;
usb_frlength_t max_data_length;
usb_frlength_t sumlen; /* sum of all lengths in bytes */
usb_frlength_t actlen; /* actual length in bytes */
usb_timeout_t timeout; /* milliseconds */
usb_frcount_t max_frame_count; /* initial value of "nframes" after
* setup */
usb_frcount_t nframes; /* number of USB frames to transfer */
usb_frcount_t aframes; /* actual number of USB frames
* transferred */
usb_stream_t stream_id; /* USB3.0 specific field */
uint16_t max_packet_size;
uint16_t max_frame_size;
uint16_t qh_pos;
uint16_t isoc_time_complete; /* in ms */
usb_timeout_t interval; /* milliseconds */
uint8_t address; /* physical USB address */
uint8_t endpointno; /* physical USB endpoint */
uint8_t max_packet_count;
uint8_t usb_state;
uint8_t fps_shift; /* down shift of FPS, 0..3 */
usb_error_t error;
struct usb_xfer_flags flags;
struct usb_xfer_flags_int flags_int;
};
/* external variables */
extern struct mtx usb_ref_lock;
extern const struct usb_string_lang usb_string_lang_en;
/* typedefs */
typedef struct malloc_type *usb_malloc_type;
/* prototypes */
#endif /* _USB_CORE_H_ */
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