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7fb57a019f
Rework the locking and lifecycle management in the cdc-acm driver. Instead of using a global mutex to prevent the 'acm' object from being freed, use the tty_port kref to keep the device alive when either the USB side or TTY side is still active. This allows us to use the global mutex purely for protecting the acm_table, while use acm->mutex to guard against disconnect during TTY port activation and shutdown. The USB-side kref is taken during port initialization in probe(), and released at the end of disconnect(). The TTY-side kref is taken in install() and released in cleanup(). On disconnect, tty_vhangup() is called instead of tty_hangup() to ensure the TTY hangup processing is completed before the USB device is taken down. The TTY open and close handlers have been gutted and replaced with tty_port_open() and tty_port_close() respectively. The driver-specific code which used to be there was spread across install(), activate() and shutdown(). Reported-by: Dave Jones <davej@redhat.com> Cc: Alan Cox <alan@linux.intel.com> Cc: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Havard Skinnemoen <hskinnemoen@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
130 lines
3.5 KiB
C
130 lines
3.5 KiB
C
/*
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*
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* Includes for cdc-acm.c
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*
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* Mainly take from usbnet's cdc-ether part
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*
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*/
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/*
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* CMSPAR, some architectures can't have space and mark parity.
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*/
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#ifndef CMSPAR
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#define CMSPAR 0
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#endif
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/*
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* Major and minor numbers.
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*/
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#define ACM_TTY_MAJOR 166
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#define ACM_TTY_MINORS 32
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/*
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* Requests.
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*/
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#define USB_RT_ACM (USB_TYPE_CLASS | USB_RECIP_INTERFACE)
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/*
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* Output control lines.
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*/
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#define ACM_CTRL_DTR 0x01
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#define ACM_CTRL_RTS 0x02
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/*
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* Input control lines and line errors.
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*/
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#define ACM_CTRL_DCD 0x01
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#define ACM_CTRL_DSR 0x02
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#define ACM_CTRL_BRK 0x04
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#define ACM_CTRL_RI 0x08
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#define ACM_CTRL_FRAMING 0x10
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#define ACM_CTRL_PARITY 0x20
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#define ACM_CTRL_OVERRUN 0x40
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/*
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* Internal driver structures.
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*/
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/*
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* The only reason to have several buffers is to accommodate assumptions
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* in line disciplines. They ask for empty space amount, receive our URB size,
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* and proceed to issue several 1-character writes, assuming they will fit.
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* The very first write takes a complete URB. Fortunately, this only happens
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* when processing onlcr, so we only need 2 buffers. These values must be
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* powers of 2.
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*/
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#define ACM_NW 16
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#define ACM_NR 16
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struct acm_wb {
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unsigned char *buf;
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dma_addr_t dmah;
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int len;
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int use;
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struct urb *urb;
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struct acm *instance;
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};
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struct acm_rb {
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int size;
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unsigned char *base;
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dma_addr_t dma;
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int index;
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struct acm *instance;
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};
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struct acm {
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struct usb_device *dev; /* the corresponding usb device */
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struct usb_interface *control; /* control interface */
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struct usb_interface *data; /* data interface */
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struct tty_port port; /* our tty port data */
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struct urb *ctrlurb; /* urbs */
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u8 *ctrl_buffer; /* buffers of urbs */
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dma_addr_t ctrl_dma; /* dma handles of buffers */
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u8 *country_codes; /* country codes from device */
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unsigned int country_code_size; /* size of this buffer */
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unsigned int country_rel_date; /* release date of version */
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struct acm_wb wb[ACM_NW];
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unsigned long read_urbs_free;
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struct urb *read_urbs[ACM_NR];
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struct acm_rb read_buffers[ACM_NR];
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int rx_buflimit;
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int rx_endpoint;
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spinlock_t read_lock;
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int write_used; /* number of non-empty write buffers */
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int transmitting;
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spinlock_t write_lock;
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struct mutex mutex;
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bool disconnected;
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struct usb_cdc_line_coding line; /* bits, stop, parity */
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struct work_struct work; /* work queue entry for line discipline waking up */
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unsigned int ctrlin; /* input control lines (DCD, DSR, RI, break, overruns) */
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unsigned int ctrlout; /* output control lines (DTR, RTS) */
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unsigned int writesize; /* max packet size for the output bulk endpoint */
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unsigned int readsize,ctrlsize; /* buffer sizes for freeing */
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unsigned int minor; /* acm minor number */
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unsigned char clocal; /* termios CLOCAL */
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unsigned int ctrl_caps; /* control capabilities from the class specific header */
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unsigned int susp_count; /* number of suspended interfaces */
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unsigned int combined_interfaces:1; /* control and data collapsed */
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unsigned int is_int_ep:1; /* interrupt endpoints contrary to spec used */
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unsigned int throttled:1; /* actually throttled */
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unsigned int throttle_req:1; /* throttle requested */
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u8 bInterval;
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struct acm_wb *delayed_wb; /* write queued for a device about to be woken */
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};
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#define CDC_DATA_INTERFACE_TYPE 0x0a
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/* constants describing various quirks and errors */
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#define NO_UNION_NORMAL 1
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#define SINGLE_RX_URB 2
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#define NO_CAP_LINE 4
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#define NOT_A_MODEM 8
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#define NO_DATA_INTERFACE 16
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