diff --git a/drivers/staging/gpib/lpvo_usb_gpib/Makefile b/drivers/staging/gpib/lpvo_usb_gpib/Makefile new file mode 100644 index 00000000000000..137511acce6352 --- /dev/null +++ b/drivers/staging/gpib/lpvo_usb_gpib/Makefile @@ -0,0 +1,3 @@ + +obj-m += lpvo_usb_gpib.o + diff --git a/drivers/staging/gpib/lpvo_usb_gpib/lpvo_usb_gpib.c b/drivers/staging/gpib/lpvo_usb_gpib/lpvo_usb_gpib.c new file mode 100644 index 00000000000000..aa7af352e709bd --- /dev/null +++ b/drivers/staging/gpib/lpvo_usb_gpib/lpvo_usb_gpib.c @@ -0,0 +1,2135 @@ +// SPDX-License-Identifier: GPL-2.0 + +/*************************************************************************** + * This code has been developed at the Department of Physics (University * + * of Florence, Italy) to support in linux-gpib the open usb-gpib adapter * + * implemented at the University of Ljubljana (lpvo.fe.uni-lj.si/gpib) * + * * + * copyright : (C) 2011 Marcello Carla' * + ***************************************************************************/ + +/* base module includes */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "gpibP.h" + +MODULE_LICENSE("GPL"); + +#define NAME "lpvo_usb_gpib" + +/* + * Table of devices that work with this driver. + * + * Currently, only one device is known to be used in the + * lpvo_usb_gpib adapter (FTDI 0403:6001). + * If your adapter uses a different chip, insert a line + * in the following table with proper , . + * + * To have your chip automatically handled by the driver, + * update files "/usr/local/etc/modprobe.d/lpvo_usb_gpib.conf" + * and /usr/local/etc/udev/rules.d/99-lpvo_usb_gpib.rules. + * + */ + +static const struct usb_device_id skel_table[] = { + { USB_DEVICE(0x0403, 0x6001) }, + { } /* Terminating entry */ +}; +MODULE_DEVICE_TABLE(usb, skel_table); + +/* + * *** Diagnostics and Debug *** + * + * The module parameter "debug" controls the sending of debug messages to + * syslog. By default it is set to 0 or 1 according to GPIB_CONFIG_KERNEL_DEBUG. + * debug = 0: only register/deregister messages are generated + * 1: every action is logged + * 2: extended logging; each single exchanged byte is documented + * (about twice the log volume of [1]) + * To switch debug level: + * At module loading: modprobe lpvo_usb_gpib debug={0,1,2} + * On the fly: echo {0,1,2} > /sys/modules/lpvo_usb_gpib/parameters/debug + */ +#ifdef GPIB_DEBUG +static int debug = 1; +#else +static int debug; +#endif +module_param(debug, int, 0644); + +#define DIA_LOG(level, format, ...) \ + do { if (debug >= (level)) \ + pr_alert("%s:%s - " format, NAME, __func__, ## __VA_ARGS__); } \ + while (0) + +/* standard and extended command sets of the usb-gpib adapter */ + +#define USB_GPIB_ON "\nIB\n" +#define USB_GPIB_OFF "\nIBO\n" +#define USB_GPIB_IBm0 "\nIBm0\n" /* do not assert REN with IFC */ +#define USB_GPIB_IBm1 "\nIBm1\n" /* assert REN with IFC */ +#define USB_GPIB_IBCL "\nIBZ\n" +#define USB_GPIB_STATUS "\nIBS\n" +#define USB_GPIB_READ "\nIB?\n" +#define USB_GPIB_READ_1 "\nIBB\n" +#define USB_GPIB_EOI "\nIBe0\n" +#define USB_GPIB_FTMO "\nIBf0\n" /* disable first byte timeout */ +#define USB_GPIB_TTMOZ "\nIBt0\n" /* disable byte timeout */ + +/* incomplete commands */ + +#define USB_GPIB_BTMO "\nIBt" /* set byte timeout */ +#define USB_GPIB_TTMO "\nIBT" /* set total timeout */ + +#define USB_GPIB_DEBUG_ON "\nIBDE\xAA\n" +#define USB_GPIB_SET_LISTEN "\nIBDT0\n" +#define USB_GPIB_SET_TALK "\nIBDT1\n" +#define USB_GPIB_SET_LINES "\nIBDC\n" +#define USB_GPIB_SET_DATA "\nIBDM\n" +#define USB_GPIB_READ_LINES "\nIBD?C\n" +#define USB_GPIB_READ_DATA "\nIBD?M\n" +#define USB_GPIB_READ_BUS "\nIBD??\n" + +/* command sequences */ + +#define USB_GPIB_UNTALK "\nIBC_\n" +#define USB_GPIB_UNLISTEN "\nIBC?\n" + +/* special characters used by the adapter */ + +#define DLE ('\020') +#define STX ('\02') +#define ETX ('\03') +#define ACK ('\06') +#define NODATA ('\03') +#define NODAV ('\011') + +#define IB_BUS_REN 0x01 +#define IB_BUS_IFC 0x02 +#define IB_BUS_NDAC 0x04 +#define IB_BUS_NRFD 0x08 +#define IB_BUS_DAV 0x10 +#define IB_BUS_EOI 0x20 +#define IB_BUS_ATN 0x40 +#define IB_BUS_SRQ 0x80 + +#define INBUF_SIZE 128 + +struct char_buf { /* used by one_char() routine */ + char *inbuf; + int last; + int nchar; +}; + +struct usb_gpib_priv { /* private data to the device */ + u8 eos; /* eos character */ + short eos_flags; /* eos mode */ + int timeout; /* current value for timeout */ + void *dev; /* the usb device private data structure */ +}; + +#define GPIB_DEV (((struct usb_gpib_priv *)board->private_data)->dev) + +#define SHOW_STATUS(board) { \ + DIA_LOG(2, "# - board %p\n", board); \ + DIA_LOG(2, "# - buffer_length %d\n", board->buffer_length); \ + DIA_LOG(2, "# - status %lx\n", board->status); \ + DIA_LOG(2, "# - use_count %d\n", board->use_count); \ + DIA_LOG(2, "# - pad %x\n", board->pad); \ + DIA_LOG(2, "# - sad %x\n", board->sad); \ + DIA_LOG(2, "# - timeout %d\n", board->usec_timeout); \ + DIA_LOG(2, "# - ppc %d\n", board->parallel_poll_configuration); \ + DIA_LOG(2, "# - t1delay %d\n", board->t1_nano_sec); \ + DIA_LOG(2, "# - online %d\n", board->online); \ + DIA_LOG(2, "# - autopoll %d\n", board->autospollers); \ + DIA_LOG(2, "# - autopoll task %p\n", board->autospoll_task); \ + DIA_LOG(2, "# - minor %d\n", board->minor); \ + DIA_LOG(2, "# - master %d\n", board->master); \ + DIA_LOG(2, "# - list %d\n", board->ist); \ + } +/* + * n = 0; + * list_for_each (l, &board->device_list) n++; + * TTY_LOG ("%s:%s - devices in list %d\n", a, b, n); + */ + +/* + * TTY_LOG - write a message to the current work terminal (if any) + */ + +#define TTY_LOG(format, ...) { \ + char buf[128]; \ + struct tty_struct *tty = get_current_tty(); \ + if (tty) { \ + snprintf(buf, 128, format, __VA_ARGS__); \ + tty->driver->ops->write(tty, buf, strlen(buf)); \ + tty->driver->ops->write(tty, "\r", 1); \ + } \ + } + +/* + * GLOBAL VARIABLES: required for + * pairing among gpib minor and usb minor. + * MAX_DEV is the max number of usb-gpib adapters; free + * to change as you like, but no more than 32 + */ + +#define MAX_DEV 8 +static struct usb_interface *lpvo_usb_interfaces[MAX_DEV]; /* registered interfaces */ +static int usb_minors[MAX_DEV]; /* usb minors */ +static int assigned_usb_minors; /* mask of filled slots */ +static struct mutex minors_lock; /* operations on usb_minors are to be protected */ + +/* + * usb-skeleton prototypes + */ + +struct usb_skel; +static ssize_t skel_do_write(struct usb_skel *, const char *, size_t); +static ssize_t skel_do_read(struct usb_skel *, char *, size_t); +static int skel_do_open(gpib_board_t *, int); +static int skel_do_release(gpib_board_t *); + +/* + * usec_diff : take difference in MICROsec between two 'timespec' + * (unix time in sec and NANOsec) + */ + +inline int usec_diff(struct timespec64 *a, struct timespec64 *b) +{ + return ((a->tv_sec - b->tv_sec) * 1000000 + + (a->tv_nsec - b->tv_nsec) / 1000); +} + +/* + * *** these routines are specific to the usb-gpib adapter *** + */ + +/** + * write_loop() - Send a byte sequence to the adapter + * + * @dev: the private device structure + * @msg: the byte sequence. + * @leng: the byte sequence length. + * + */ + +static int write_loop(void *dev, char *msg, int leng) +{ +// int nchar = 0, val; + +// do { + + return skel_do_write(dev, msg, leng); + +// if (val < 1) { +// printk (KERN_ALERT "%s:%s - write error: %d %d/%d\n", +// NAME, __func__, val, nchar, leng); +// return -EIO; +// } +// nchar +=val; +// } while (nchar < leng); +// return leng; +} + +static char printable(char x) +{ + if (x < 32 || x > 126) + return ' '; + return x; +} + +/** + * send_command() - Send a byte sequence and return a single byte reply. + * + * @board: the gpib_board_struct data area for this gpib interface + * @msg: the byte sequence. + * @leng the byte sequence length; can be given as zero and is + * computed automatically, but if 'msg' contains a zero byte, + * it has to be given explicitly. + */ + +static int send_command(gpib_board_t *board, char *msg, int leng) +{ + char buffer[64]; + int nchar, j; + int retval; + struct timespec64 before, after; + + ktime_get_real_ts64 (&before); + + if (!leng) + leng = strlen(msg); + retval = write_loop(GPIB_DEV, msg, leng); + if (retval < 0) + return retval; + + nchar = skel_do_read(GPIB_DEV, buffer, 64); + + if (nchar < 0) { + DIA_LOG(0, " return from read: %d\n", nchar); + return nchar; + } else if (nchar != 1) { + for (j = 0 ; j < leng ; j++) { + DIA_LOG(0, " Irregular reply to command: %d %x %c\n", + j, msg[j], printable(msg[j])); + } + for (j = 0 ; j < nchar ; j++) { + DIA_LOG(0, " Irregular command reply: %d %x %c\n", + j, buffer[j] & 0xff, printable(buffer[j])); + } + return -EIO; + } + ktime_get_real_ts64 (&after); + + DIA_LOG(1, "Sent %d - done %d us.\n", leng, usec_diff(&after, &before)); + + return buffer[0] & 0xff; +} + +/* + * + * set_control_line() - Set the value of a single gpib control line + * + * @board: the gpib_board_struct data area for this gpib interface + * @line: line mask + * @value: line new value (0/1) + * + */ + +static int set_control_line(gpib_board_t *board, int line, int value) +{ + char msg[] = USB_GPIB_SET_LINES; + int retval; + int leng = strlen(msg); + + DIA_LOG(1, "setting line %x to %x\n", line, value); + + retval = send_command(board, USB_GPIB_READ_LINES, 0); + + DIA_LOG(1, "old line values: %x\n", retval); + + if (retval == -EIO) + return retval; + + msg[leng - 2] = value ? (retval & ~line) : retval | line; + + retval = send_command(board, msg, 0); + + DIA_LOG(1, "operation result: %x\n", retval); + + return retval; +} + +/* + * one_char() - read one single byte from input buffer + * + * @board: the gpib_board_struct data area for this gpib interface + * @char_buf: the routine private data structure + */ + +static int one_char(gpib_board_t *board, struct char_buf *b) +{ + struct timespec64 before, after; + + if (b->nchar) { + DIA_LOG(2, "-> %x\n", b->inbuf[b->last - b->nchar]); + return b->inbuf[b->last - b->nchar--]; + } + ktime_get_real_ts64 (&before); + b->nchar = skel_do_read(GPIB_DEV, b->inbuf, INBUF_SIZE); + b->last = b->nchar; + ktime_get_real_ts64 (&after); + + DIA_LOG(2, "read %d bytes in %d usec\n", + b->nchar, usec_diff(&after, &before)); + + if (b->nchar > 0) { + DIA_LOG(2, "--> %x\n", b->inbuf[b->last - b->nchar]); + return b->inbuf[b->last - b->nchar--]; + } else if (b->nchar == 0) { + pr_alert("%s:%s - read returned EOF\n", NAME, __func__); + return -EIO; + } + pr_alert("%s:%s - read error %d\n", NAME, __func__, b->nchar); + TTY_LOG("\n *** %s *** Read Error - %s\n", NAME, + "Reset the adapter with 'gpib_config'\n"); + return -EIO; +} + +/** + * set_timeout() - set single byte / total timeouts on the adapter + * + * @board: the gpib_board_struct data area for this gpib interface + * + * For sake of speed, the operation is performed only if it + * modifies the current (saved) value. Minimum allowed timeout + * is 30 ms (T30ms -> 8); timeout disable (TNONE -> 0) currently + * not supported. + */ + +static void set_timeout(gpib_board_t *board) +{ + int n, val; + char command[sizeof(USB_GPIB_TTMO) + 6]; + struct usb_gpib_priv *data = board->private_data; + + if (data->timeout == board->usec_timeout) + return; + + n = (board->usec_timeout + 32767) / 32768; + if (n < 2) + n = 2; + + DIA_LOG(1, "Set timeout to %d us -> %d\n", board->usec_timeout, n); + + sprintf(command, "%s%d\n", USB_GPIB_BTMO, n > 255 ? 255 : n); + val = send_command(board, command, 0); + + if (val == ACK) { + if (n > 65535) + n = 65535; + sprintf(command, "%s%d\n", USB_GPIB_TTMO, n); + val = send_command(board, command, 0); + } + + if (val != ACK) { + pr_alert("%s:%s - error in timeout set: <%s>\n", + NAME, __func__, command); + } else { + data->timeout = board->usec_timeout; + } +} + +/* + * now the standard interface functions - attach and detach + */ + +/** + * usb_gpib_attach() - activate the usb-gpib converter board + * + * @board: the gpib_board_struct data area for this gpib interface + * @config: firmware data, if any (from gpib_config -I ) + * + * The channel name is ttyUSBn, with n=0 by default. Other values for n + * passed with gpib_config -b . + * + * In this routine I trust that when an error code is returned + * detach() will be called. Always. + */ + +static int usb_gpib_attach(gpib_board_t *board, const gpib_board_config_t *config) +{ + int retval, j; + int base = (long)config->ibbase; + char *device_path; + int match; + struct usb_device *udev; + + DIA_LOG(0, "Board %p -t %s -m %d -a %p -u %d -l %d -b %d\n", + board, board->interface->name, board->minor, config->device_path, + config->pci_bus, config->pci_slot, base); + + board->private_data = NULL; /* to be sure - we can detach before setting */ + + /* identify device to be attached */ + + mutex_lock(&minors_lock); + + if (config->device_path) { + /* if config->device_path given, try that first */ + pr_alert("%s:%s - Looking for device_path: %s\n", + NAME, __func__, config->device_path); + for (j = 0 ; j < MAX_DEV ; j++) { + if ((assigned_usb_minors & 1 << j) == 0) + continue; + udev = usb_get_dev(interface_to_usbdev(lpvo_usb_interfaces[j])); + device_path = kobject_get_path(&udev->dev.kobj, GFP_KERNEL); + match = gpib_match_device_path(&lpvo_usb_interfaces[j]->dev, + config->device_path); + DIA_LOG(1, "dev. %d: minor %d path: %s --> %d\n", j, + lpvo_usb_interfaces[j]->minor, device_path, match); + kfree(device_path); + if (match) + break; + } + } else if (config->pci_bus != -1 && config->pci_slot != -1) { + /* second: look for bus and slot */ + for (j = 0 ; j < MAX_DEV ; j++) { + if ((assigned_usb_minors & 1 << j) == 0) + continue; + udev = usb_get_dev(interface_to_usbdev(lpvo_usb_interfaces[j])); + DIA_LOG(1, "dev. %d: bus %d -> %d dev: %d -> %d\n", j, + udev->bus->busnum, config->pci_bus, udev->devnum, config->pci_slot); + if (config->pci_bus == udev->bus->busnum && + config->pci_slot == udev->devnum) + break; + } + } else { /* last chance: usb_minor, given as ibbase */ + for (j = 0 ; j < MAX_DEV ; j++) { + if (usb_minors[j] == base && assigned_usb_minors & 1 << j) + break; + } + } + mutex_unlock(&minors_lock); + + if (j == MAX_DEV) { + pr_alert("%s:%s - Requested device is not registered.\n", NAME, __func__); + return -EIO; + } + + board->private_data = kzalloc(sizeof(struct usb_gpib_priv), GFP_KERNEL); + if (!board->private_data) + return -ENOMEM; + + retval = skel_do_open(board, usb_minors[j]); + + DIA_LOG(1, "Skel open: %d\n", retval); + + if (retval) { + TTY_LOG("%s:%s - skel open failed.\n", NAME, __func__); + kfree(board->private_data); + board->private_data = NULL; + return -ENODEV; + } + + SHOW_STATUS(board); + + retval = send_command(board, USB_GPIB_ON, 0); + DIA_LOG(1, "USB_GPIB_ON returns %x\n", retval); + if (retval != ACK) + return -EIO; + + /* We must setup debug mode because we need the extended instruction + * set to cope with the Core (gpib_common) point of view + */ + + retval = send_command(board, USB_GPIB_DEBUG_ON, 0); + DIA_LOG(1, "USB_GPIB_DEBUG_ON returns %x\n", retval); + if (retval != ACK) + return -EIO; + + /* We must keep REN off after an IFC because so it is + * assumed by the Core + */ + + retval = send_command(board, USB_GPIB_IBm0, 0); + DIA_LOG(1, "USB_GPIB_IBm0 returns %x\n", retval); + if (retval != ACK) + return -EIO; + + retval = set_control_line(board, IB_BUS_REN, 0); + if (retval != ACK) + return -EIO; + + retval = send_command(board, USB_GPIB_FTMO, 0); + DIA_LOG(1, "USB_GPIB_FTMO returns %x\n", retval); + if (retval != ACK) + return -EIO; + + SHOW_STATUS(board); + TTY_LOG("Module '%s' has been sucesfully configured\n", NAME); + return 0; +} + +/** + * usb_gpib_detach() - deactivate the usb-gpib converter board + * + * @board: the gpib_board data area for this gpib interface + * + */ + +static void usb_gpib_detach(gpib_board_t *board) +{ + int retval; + + SHOW_STATUS(board); + + DIA_LOG(0, "detaching %p\n", board); + + if (board->private_data) { + if (GPIB_DEV) { + write_loop(GPIB_DEV, USB_GPIB_OFF, strlen(USB_GPIB_OFF)); + msleep(100); + DIA_LOG(1, "%s", "GPIB off\n"); + retval = skel_do_release(board); + DIA_LOG(1, "skel release -> %d\n", retval); + } + kfree(board->private_data); + board->private_data = NULL; + } + + DIA_LOG(0, "done %p\n", board); + TTY_LOG("Module '%s' has been detached\n", NAME); +} + +/* + * Other functions follow in alphabetical order + */ +/* command */ +static int usb_gpib_command(gpib_board_t *board, + u8 *buffer, + size_t length, + size_t *bytes_written) +{ + int i, retval; + char command[6] = "IBc\n"; + + DIA_LOG(1, "enter %p\n", board); + + set_timeout(board); + + for (i = 0 ; i < length ; i++) { + command[3] = buffer[i]; + retval = send_command(board, command, 5); + DIA_LOG(2, "%d ==> %x %x\n", i, buffer[i], retval); + if (retval != 0x06) + return retval; + ++(*bytes_written); + } + return 0; +} + +/** + * disable_eos() - Disable END on eos byte (END on EOI only) + * + * @board: the gpib_board data area for this gpib interface + * + * With the lpvo adapter eos can only be handled via software. + * Cannot do nothing here, but remember for future use. + */ + +static void usb_gpib_disable_eos(gpib_board_t *board) +{ + ((struct usb_gpib_priv *)board->private_data)->eos_flags &= ~REOS; + DIA_LOG(1, "done: %x\n", + ((struct usb_gpib_priv *)board->private_data)->eos_flags); +} + +/** + * enable_eos() - Enable END for reads when eos byte is received. + * + * @board: the gpib_board data area for this gpib interface + * @eos_byte: the 'eos' byte + * @compare_8_bits: if zero ignore eigthth bit when comparing + * + */ + +static int usb_gpib_enable_eos(gpib_board_t *board, + u8 eos_byte, + int compare_8_bits) +{ + struct usb_gpib_priv *pd = (struct usb_gpib_priv *)board->private_data; + + DIA_LOG(1, "enter with %x\n", eos_byte); + pd->eos = eos_byte; + pd->eos_flags = REOS; + if (compare_8_bits) + pd->eos_flags |= BIN; + return 0; +} + +/** + * go_to_standby() - De-assert ATN + * + * @board: the gpib_board data area for this gpib interface + */ + +static int usb_gpib_go_to_standby(gpib_board_t *board) +{ + int retval = set_control_line(board, IB_BUS_ATN, 0); + + DIA_LOG(1, "done with %x\n", retval); + + if (retval == ACK) + return 0; + return -EIO; +} + +/** + * interface_clear() - Assert or de-assert IFC + * + * @board: the gpib_board data area for this gpib interface + * assert: 1: assert IFC; 0: de-assert IFC + * + * Currently on the assert request we issue the lpvo IBZ + * command that cycles IFC low for 100 usec, then we ignore + * the de-assert request. + */ + +static void usb_gpib_interface_clear(gpib_board_t *board, int assert) +{ + int retval = 0; + + DIA_LOG(1, "enter with %d\n", assert); + + if (assert) { + retval = send_command(board, USB_GPIB_IBCL, 0); + + set_bit(CIC_NUM, &board->status); + } + + DIA_LOG(1, "done with %d %d\n", assert, retval); +} + +/** + * line_status() - Read the status of the bus lines. + * + * @board: the gpib_board data area for this gpib interface + * + * We can read all lines. + */ + +#define WQT wait_queue_entry_t +#define WQH head +#define WQE entry + +static int usb_gpib_line_status(const gpib_board_t *board) +{ + int buffer; + int line_status = ValidALL; /* all lines will be read */ + struct list_head *p, *q; + WQT *item; + unsigned long flags; + int sleep = 0; + + DIA_LOG(1, "%s\n", "request"); + + /* if we are on the wait queue (board->wait), do not hurry + * reading status line; instead, pause a little + */ + + spin_lock_irqsave((spinlock_t *)&board->wait.lock, flags); + q = (struct list_head *)&board->wait.WQH; + list_for_each(p, q) { + item = container_of(p, WQT, WQE); + if (item->private == current) { + sleep = 20; + break; + } + /* pid is: ((struct task_struct *) item->private)->pid); */ + } + spin_unlock_irqrestore((spinlock_t *)&board->wait.lock, flags); + if (sleep) { + DIA_LOG(1, "we are on the wait queue - sleep %d ms\n", sleep); + msleep(sleep); + } + + buffer = send_command((gpib_board_t *)board, USB_GPIB_STATUS, 0); + + if (buffer < 0) { + pr_alert("%s:%s - line status read failed with %d\n", NAME, __func__, buffer); + return -1; + } + + if ((buffer & 0x01) == 0) + line_status |= BusREN; + if ((buffer & 0x02) == 0) + line_status |= BusIFC; + if ((buffer & 0x04) == 0) + line_status |= BusNDAC; + if ((buffer & 0x08) == 0) + line_status |= BusNRFD; + if ((buffer & 0x10) == 0) + line_status |= BusDAV; + if ((buffer & 0x20) == 0) + line_status |= BusEOI; + if ((buffer & 0x40) == 0) + line_status |= BusATN; + if ((buffer & 0x80) == 0) + line_status |= BusSRQ; + + DIA_LOG(1, "done with %x %x\n", buffer, line_status); + + return line_status; +} + +/* parallel_poll */ + +static int usb_gpib_parallel_poll(gpib_board_t *board, uint8_t *result) +{ + /* request parallel poll asserting ATN | EOI; + * we suppose ATN already asserted + */ + + int retval; + + DIA_LOG(1, "enter %p\n", board); + + retval = set_control_line(board, IB_BUS_EOI, 1); + if (retval != ACK) { + pr_alert("%s:%s - assert EOI failed\n", NAME, __func__); + return -EIO; + } + + *result = send_command(board, USB_GPIB_READ_DATA, 0); + + DIA_LOG(1, "done with %x\n", *result); + + retval = set_control_line(board, IB_BUS_EOI, 0); + if (retval != 0x06) { + pr_alert("%s:%s - unassert EOI failed\n", NAME, __func__); + return -EIO; + } + + return 0; +} + +/* read */ + +static int usb_gpib_read(gpib_board_t *board, + u8 *buffer, + size_t length, + int *end, + size_t *bytes_read) +{ +#define MAX_READ_EXCESS 16384 + + struct char_buf b = {NULL, 0}; + + int retval; + char c, nc; + int ic; + struct timespec64 before, after; + int read_count = MAX_READ_EXCESS; + struct usb_gpib_priv *pd = (struct usb_gpib_priv *)board->private_data; + + DIA_LOG(1, "enter %p -> %zu\n", board, length); + + *bytes_read = 0; /* by default, things go wrong */ + *end = 0; + + set_timeout(board); + + /* single byte read has a special handling */ + + if (length == 1) { + char inbuf[2] = {0, 0}; + + /* read a single character */ + + ktime_get_real_ts64 (&before); + + retval = write_loop(GPIB_DEV, USB_GPIB_READ_1, strlen(USB_GPIB_READ_1)); + if (retval < 0) + return retval; + + retval = skel_do_read(GPIB_DEV, inbuf, 1); + retval += skel_do_read(GPIB_DEV, inbuf + 1, 1); + + ktime_get_real_ts64 (&after); + + DIA_LOG(1, "single read: %x %x %x in %d\n", retval, + inbuf[0], inbuf[1], + usec_diff(&after, &before)); + + /* good char / last char? */ + + if (retval == 2 && inbuf[1] == ACK) { + buffer[0] = inbuf[0]; + *bytes_read = 1; + return 0; + } + if (retval < 2) + return -EIO; + else + return -ETIME; + return 0; + } + + /* allocate buffer for multibyte read */ + + b.inbuf = kmalloc(INBUF_SIZE, GFP_KERNEL); + if (!b.inbuf) + return -ENOMEM; + + /* send read command and check sequence */ + + retval = write_loop(GPIB_DEV, USB_GPIB_READ, strlen(USB_GPIB_READ)); + if (retval < 0) + goto read_return; + + if (one_char(board, &b) != DLE || one_char(board, &b) != STX) { + pr_alert("%s:%s - wrong sequence\n", + NAME, __func__); + retval = -EIO; + goto read_return; + } + + /* get data flow */ + + while (1) { + ic = one_char(board, &b); + if (ic == -EIO) { + retval = -EIO; + goto read_return; + } + c = ic; + + if (c == DLE) + nc = one_char(board, &b); + if (c != DLE || nc == DLE) { + /* data byte - store into buffer */ + + if (*bytes_read == length) + break; /* data overflow */ + if (c == DLE) + c = nc; + buffer[(*bytes_read)++] = c; + if (c == pd->eos) { + *end = 1; + break; + } + + } else { + /* we are in the closing sequence */ + + if (c == ETX) { + c = one_char(board, &b); + if (c == ACK) { + *end = 1; + retval = 0; + goto read_return; + } else { + pr_alert("%s:%s - %s %x\n", + NAME, __func__, + "Wrong end of message", c); + retval = -ETIME; + goto read_return; + } + } else { + pr_alert("%s:%s - %s\n", NAME, __func__, + "lone in stream"); + retval = -EIO; + goto read_return; + } + } + } + + /* we had a data overflow - flush excess data */ + + while (read_count--) { + if (one_char(board, &b) != DLE) + continue; + c = one_char(board, &b); + if (c == DLE) + continue; + if (c == ETX) { + c = one_char(board, &b); + if (c == ACK) { + if (MAX_READ_EXCESS - read_count > 1) + pr_alert("%s:%s - %s\n", NAME, __func__, + "small buffer - maybe some data lost"); + retval = 0; + goto read_return; + } + break; + } + } + + pr_alert("%s:%s - no input end - GPIB board in odd state\n", + NAME, __func__); + retval = -EIO; + +read_return: + kfree(b.inbuf); + + DIA_LOG(1, "done with byte/status: %d %x %d\n", + (int)*bytes_read, retval, *end); + + if (retval == 0 || retval == -ETIME) { + if (send_command(board, USB_GPIB_UNTALK, sizeof(USB_GPIB_UNTALK)) == 0x06) + return retval; + return -EIO; + } + + return retval; +} + +/* remote_enable */ + +static void usb_gpib_remote_enable(gpib_board_t *board, int enable) +{ + int retval; + + retval = set_control_line(board, IB_BUS_REN, enable ? 1 : 0); + if (retval != ACK) + pr_alert("%s:%s - could not set REN line: %x\n", + NAME, __func__, retval); + + DIA_LOG(1, "done with %x\n", retval); +} + +/* request_system_control */ + +static void usb_gpib_request_system_control(gpib_board_t *board, + int request_control) +{ + if (request_control) + set_bit(CIC_NUM, &board->status); + else + clear_bit(CIC_NUM, &board->status); + + DIA_LOG(1, "done with %d -> %lx\n", request_control, board->status); +} + +/* take_control */ +/* beware: the sync flag is ignored; what is its real meaning? */ + +static int usb_gpib_take_control(gpib_board_t *board, int sync) +{ + int retval; + + retval = set_control_line(board, IB_BUS_ATN, 1); + + DIA_LOG(1, "done with %d %x\n", sync, retval); + + if (retval == ACK) + return 0; + return -EIO; +} + +/* update_status */ + +static unsigned int usb_gpib_update_status(gpib_board_t *board, + unsigned int clear_mask) +{ + /* There is nothing we can do here, I guess */ + + board->status &= ~clear_mask; + + DIA_LOG(1, "done with %x %lx\n", clear_mask, board->status); + + return board->status; +} + +/* write */ +/* beware: DLE characters are not escaped - can only send ASCII data */ + +static int usb_gpib_write(gpib_board_t *board, + u8 *buffer, + size_t length, + int send_eoi, + size_t *bytes_written) +{ + int retval; + char *msg; + + DIA_LOG(1, "enter %p -> %zu\n", board, length); + + set_timeout(board); + + msg = kmalloc(length + 8, GFP_KERNEL); + if (!msg) + return -ENOMEM; + + memcpy(msg, "\nIB\020\002", 5); + memcpy(msg + 5, buffer, length); + memcpy(msg + 5 + length, "\020\003\n", 3); + + retval = send_command(board, msg, length + 8); + kfree(msg); + + DIA_LOG(1, "<%.*s> -> %x\n", (int)length, buffer, retval); + + if (retval != ACK) + return -EPIPE; + + *bytes_written = length; + + if (send_command(board, USB_GPIB_UNLISTEN, sizeof(USB_GPIB_UNLISTEN)) + != 0x06) + return -EPIPE; + + return length; +} + +/* + * *** following functions not implemented yet *** + */ + +/* parallel_poll configure */ + +static void usb_gpib_parallel_poll_configure(gpib_board_t *board, + uint8_t configuration) +{ + pr_alert("%s:%s - currently a NOP\n", NAME, __func__); +} + +/* parallel_poll_response */ + +static void usb_gpib_parallel_poll_response(gpib_board_t *board, int ist) +{ + pr_alert("%s:%s - currently a NOP\n", NAME, __func__); +} + +/* primary_address */ + +static int usb_gpib_primary_address(gpib_board_t *board, unsigned int address) +{ + pr_alert("%s:%s - currently a NOP\n", NAME, __func__); + return 0; +} + +/* return_to_local */ + +static void usb_gpib_return_to_local(gpib_board_t *board) +{ + pr_alert("%s:%s - currently a NOP\n", NAME, __func__); +} + +/* secondary_address */ + +static int usb_gpib_secondary_address(gpib_board_t *board, + unsigned int address, + int enable) +{ + pr_alert("%s:%s - currently a NOP\n", NAME, __func__); + return 0; +} + +/* serial_poll_response */ + +static void usb_gpib_serial_poll_response(gpib_board_t *board, uint8_t status) +{ + pr_alert("%s:%s - currently a NOP\n", NAME, __func__); +} + +/* serial_poll_status */ + +static uint8_t usb_gpib_serial_poll_status(gpib_board_t *board) +{ + pr_alert("%s:%s - currently a NOP\n", NAME, __func__); + return 0; +} + +/* t1_delay */ + +static unsigned int usb_gpib_t1_delay(gpib_board_t *board, unsigned int nano_sec) +{ + pr_alert("%s:%s - currently a NOP\n", NAME, __func__); + return 0; +} + +/* + * *** module dispatch table and init/exit functions *** + */ + +gpib_interface_t usb_gpib_interface = { +name: NAME, +attach : usb_gpib_attach, +detach : usb_gpib_detach, +read : usb_gpib_read, +write : usb_gpib_write, +command : usb_gpib_command, +take_control : usb_gpib_take_control, +go_to_standby : usb_gpib_go_to_standby, +request_system_control : usb_gpib_request_system_control, +interface_clear : usb_gpib_interface_clear, +remote_enable : usb_gpib_remote_enable, +enable_eos : usb_gpib_enable_eos, +disable_eos : usb_gpib_disable_eos, +parallel_poll : usb_gpib_parallel_poll, +parallel_poll_configure : usb_gpib_parallel_poll_configure, +parallel_poll_response : usb_gpib_parallel_poll_response, +local_parallel_poll_mode : NULL, // XXX +line_status : usb_gpib_line_status, +update_status : usb_gpib_update_status, +primary_address : usb_gpib_primary_address, +secondary_address : usb_gpib_secondary_address, +serial_poll_response : usb_gpib_serial_poll_response, +serial_poll_status : usb_gpib_serial_poll_status, +t1_delay : usb_gpib_t1_delay, +return_to_local : usb_gpib_return_to_local, +skip_check_for_command_acceptors : 1 +}; + +/* + * usb_gpib_init_module(), usb_gpib_exit_module() + * + * This functions are called every time a new device is detected + * and registered or is removed and unregistered. + * We must take note of created and destroyed usb minors to be used + * when usb_gpib_attach() and usb_gpib_detach() will be called on + * request by gpib_config. + */ + +static int usb_gpib_init_module(struct usb_interface *interface) +{ + int j, mask, rv; + + rv = mutex_lock_interruptible(&minors_lock); + if (rv < 0) + return rv; + + if (!assigned_usb_minors) { + gpib_register_driver(&usb_gpib_interface, THIS_MODULE); + } else { + /* check if minor is already registered - maybe useless, but if + * it happens the code is inconsistent somewhere + */ + + for (j = 0 ; j < MAX_DEV ; j++) { + if (usb_minors[j] == interface->minor && assigned_usb_minors & 1 << j) { + pr_alert("%s:%s - CODE BUG: USB minor %d registered at %d.\n", + NAME, __func__, interface->minor, j); + rv = -1; + goto exit; + } + } + } + + /* find a free slot */ + + for (j = 0 ; j < MAX_DEV ; j++) { + mask = 1 << j; + if ((assigned_usb_minors & mask) == 0) { + usb_minors[j] = interface->minor; + lpvo_usb_interfaces[j] = interface; + assigned_usb_minors |= mask; + DIA_LOG(0, "usb minor %d registered at %d\n", interface->minor, j); + rv = 0; + goto exit; + } + } + pr_alert("%s:%s - No slot available for interface %p minor %d\n", + NAME, __func__, interface, interface->minor); + rv = -1; + +exit: + mutex_unlock(&minors_lock); + return rv; +} + +static void usb_gpib_exit_module(int minor) +{ + int j; + + mutex_lock(&minors_lock); + for (j = 0 ; j < MAX_DEV ; j++) { + if (usb_minors[j] == minor && assigned_usb_minors & 1 << j) { + assigned_usb_minors &= ~(1 << j); + usb_minors[j] = -1; + if (assigned_usb_minors == 0) + gpib_unregister_driver(&usb_gpib_interface); + goto exit; + } + } + pr_alert("%s:%s - CODE BUG: USB minor %d not found.\n", NAME, __func__, minor); + +exit: + mutex_unlock(&minors_lock); +} + +/* + * Default latency time (16 msec) is too long. + * We must use 1 msec (best); anyhow, no more than 5 msec. + * + * Defines and function taken and modified from the kernel tree + * (see ftdi_sio.h and ftdi_sio.c). + * + */ + +#define FTDI_SIO_SET_LATENCY_TIMER 9 /* Set the latency timer */ +#define FTDI_SIO_SET_LATENCY_TIMER_REQUEST FTDI_SIO_SET_LATENCY_TIMER +#define FTDI_SIO_SET_LATENCY_TIMER_REQUEST_TYPE 0x40 +#define WDR_TIMEOUT 5000 /* default urb timeout */ +#define WDR_SHORT_TIMEOUT 1000 /* shorter urb timeout */ + +#define LATENCY_TIMER 1 /* use a small latency timer: 1 ... 5 msec */ +#define LATENCY_CHANNEL 0 /* channel selection in multichannel devices */ +static int write_latency_timer(struct usb_device *udev) +{ + int rv = usb_control_msg(udev, + usb_sndctrlpipe(udev, 0), + FTDI_SIO_SET_LATENCY_TIMER_REQUEST, + FTDI_SIO_SET_LATENCY_TIMER_REQUEST_TYPE, + LATENCY_TIMER, LATENCY_CHANNEL, + NULL, 0, WDR_TIMEOUT); + if (rv < 0) + pr_alert("Unable to write latency timer: %i\n", rv); + return rv; +} + +/***************************************************************************** + * * + * The following code is a modified version of the USB Skeleton driver * + * written by Greg Kroah-Hartman and available in the kernel tree. * + * * + * Functions skel_open() and skel_release() have been rewritten and named * + * skel_do_open() and skel_do_release() to process the attach and detach * + * requests coming from gpib_config. * + * * + * Functions skel_read() and skel_write() have been split into a * + * skel_do_read() and skel_do_write(), that cover the kernel stuff of read * + * and write operations, and the original skel_read() and skel_write(), * + * that handle communication with user space and call their _do_ companion. * + * * + * Only the _do_ versions are used by the lpvo_usb_gpib driver; other ones * + * can be (optionally) maintained in the compilation to have direct access * + * to a gpib controller for debug and diagnostics. * + * * + * To avoid collisions in names, devices in user space have been renamed * + * lpvo_raw1, lpvo_raw2 .... and the usb driver has been renamed with the * + * gpib module name. * + * * + *****************************************************************************/ + +/* + * USB Skeleton driver - 2.2 + * + * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com) + * + * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c + * but has been rewritten to be easier to read and use. + */ + +#include +#include +#include +#include + +/* Get a minor range for your devices from the usb maintainer */ +#define USB_SKEL_MINOR_BASE 192 + +/* private defines */ + +#define MAX_TRANSFER (PAGE_SIZE - 512) +/* MAX_TRANSFER is chosen so that the VM is not stressed by + * allocations > PAGE_SIZE and the number of packets in a page + * is an integer 512 is the largest possible packet on EHCI + */ + +#define WRITES_IN_FLIGHT 1 /* we do not want more than one pending write */ +#define USER_DEVICE 1 /* compile for device(s) in user space */ + +/* Structure to hold all of our device specific stuff */ +struct usb_skel { + struct usb_device *udev; /* the usb device for this device */ + struct usb_interface *interface; /* the interface for this device */ + struct semaphore limit_sem; /* limiting the number of writes in progress */ + struct usb_anchor submitted; /* in case need to retract our submissions */ + struct urb *bulk_in_urb; /* the urb to read data with */ + unsigned char *bulk_in_buffer; /* the buffer to receive data */ + size_t bulk_in_size; /* the size of the receive buffer */ + size_t bulk_in_filled; /* number of bytes in the buffer */ + size_t bulk_in_copied; /* already copied to user space */ + __u8 bulk_in_endpoint_addr; /* the address of the bulk in endpoint */ + __u8 bulk_out_endpoint_addr; /* the address of the bulk out endpoint */ + int errors; /* the last request tanked */ + bool ongoing_read; /* a read is going on */ + spinlock_t err_lock; /* lock for errors */ + struct kref kref; + struct mutex io_mutex; /* synchronize I/O with disconnect */ + wait_queue_head_t bulk_in_wait; /* to wait for an ongoing read */ +}; + +#define to_skel_dev(d) container_of(d, struct usb_skel, kref) + +static struct usb_driver skel_driver; +static void skel_draw_down(struct usb_skel *dev); + +static void skel_delete(struct kref *kref) +{ + struct usb_skel *dev = to_skel_dev(kref); + + usb_free_urb(dev->bulk_in_urb); + usb_put_dev(dev->udev); + kfree(dev->bulk_in_buffer); + kfree(dev); +} + +/* + * skel_do_open() - to be called by usb_gpib_attach + */ + +static int skel_do_open(gpib_board_t *board, int subminor) +{ + struct usb_skel *dev; + struct usb_interface *interface; + int retval = 0; + + DIA_LOG(0, "Required minor: %d\n", subminor); + + interface = usb_find_interface(&skel_driver, subminor); + if (!interface) { + pr_err("%s - error, can't find device for minor %d\n", + __func__, subminor); + retval = -ENODEV; + goto exit; + } + + dev = usb_get_intfdata(interface); + if (!dev) { + retval = -ENODEV; + goto exit; + } + + retval = usb_autopm_get_interface(interface); + if (retval) + goto exit; + + /* increment our usage count for the device */ + kref_get(&dev->kref); + + /* save our object in the file's private structure */ + GPIB_DEV = dev; + +exit: + return retval; +} + +/* + * skel_do_release() - to be called by usb_gpib_detach + */ + +static int skel_do_release(gpib_board_t *board) +{ + struct usb_skel *dev; + + dev = GPIB_DEV; + if (!dev) + return -ENODEV; + + /* allow the device to be autosuspended */ + mutex_lock(&dev->io_mutex); + if (dev->interface) + usb_autopm_put_interface(dev->interface); + mutex_unlock(&dev->io_mutex); + + /* decrement the count on our device */ + kref_put(&dev->kref, skel_delete); + return 0; +} + +/* + * read functions + */ + +static void skel_read_bulk_callback(struct urb *urb) +{ + struct usb_skel *dev; + unsigned long flags; + + dev = urb->context; + + spin_lock_irqsave(&dev->err_lock, flags); + /* sync/async unlink faults aren't errors */ + if (urb->status) { + if (!(urb->status == -ENOENT || + urb->status == -ECONNRESET || + urb->status == -ESHUTDOWN)) + dev_err(&dev->interface->dev, + "%s - nonzero read bulk status received: %d\n", + __func__, urb->status); + + dev->errors = urb->status; + } else { + dev->bulk_in_filled = urb->actual_length; + } + dev->ongoing_read = 0; + spin_unlock_irqrestore(&dev->err_lock, flags); + + wake_up_interruptible(&dev->bulk_in_wait); +} + +static int skel_do_read_io(struct usb_skel *dev, size_t count) +{ + int rv; + + /* prepare a read */ + usb_fill_bulk_urb(dev->bulk_in_urb, + dev->udev, + usb_rcvbulkpipe(dev->udev, + dev->bulk_in_endpoint_addr), + dev->bulk_in_buffer, + min(dev->bulk_in_size, count), + skel_read_bulk_callback, + dev); + /* tell everybody to leave the URB alone */ + spin_lock_irq(&dev->err_lock); + dev->ongoing_read = 1; + spin_unlock_irq(&dev->err_lock); + + /* submit bulk in urb, which means no data to deliver */ + dev->bulk_in_filled = 0; + dev->bulk_in_copied = 0; + + /* do it */ + rv = usb_submit_urb(dev->bulk_in_urb, GFP_KERNEL); + if (rv < 0) { + dev_err(&dev->interface->dev, + "%s - failed submitting read urb, error %d\n", + __func__, rv); + rv = (rv == -ENOMEM) ? rv : -EIO; + spin_lock_irq(&dev->err_lock); + dev->ongoing_read = 0; + spin_unlock_irq(&dev->err_lock); + } + + return rv; +} + +/* + * skel_do_read() - read operations from lpvo_usb_gpib + */ + +static ssize_t skel_do_read(struct usb_skel *dev, char *buffer, size_t count) +{ + int rv; + bool ongoing_io; + + /* if we cannot read at all, return EOF */ + + if (!dev->bulk_in_urb || !count) + return 0; + + DIA_LOG(1, "enter for %zu.\n", count); + +restart: /* added to comply with ftdi timeout technique */ + + /* no concurrent readers */ + + DIA_LOG(2, "restart with %zd %zd.\n", dev->bulk_in_filled, dev->bulk_in_copied); + + rv = mutex_lock_interruptible(&dev->io_mutex); + if (rv < 0) + return rv; + + if (!dev->interface) { /* disconnect() was called */ + rv = -ENODEV; + goto exit; + } + +retry: + /* if IO is under way, we must not touch things */ + spin_lock_irq(&dev->err_lock); + ongoing_io = dev->ongoing_read; + spin_unlock_irq(&dev->err_lock); + + DIA_LOG(2, "retry with %d.\n", ongoing_io); + + if (ongoing_io) { +// /* nonblocking IO shall not wait */ +// /* no file, no O_NONBLOCK; maybe provide when from user space */ +// if (file->f_flags & O_NONBLOCK) { +// rv = -EAGAIN; +// goto exit; +// } + + /* + * IO may take forever + * hence wait in an interruptible state + */ + rv = wait_event_interruptible(dev->bulk_in_wait, (!dev->ongoing_read)); + if (rv < 0) + goto exit; + } + + /* errors must be reported */ + rv = dev->errors; + if (rv < 0) { + /* any error is reported once */ + dev->errors = 0; + /* to preserve notifications about reset */ + rv = (rv == -EPIPE) ? rv : -EIO; + /* report it */ + goto exit; + } + + /* + * if the buffer is filled we may satisfy the read + * else we need to start IO + */ + + if (dev->bulk_in_filled) { + /* we had read data */ + + size_t available = dev->bulk_in_filled - dev->bulk_in_copied; +// size_t chunk = min(available, count); /* compute chunk later */ + size_t chunk; + + DIA_LOG(2, "we have data: %zu %zu.\n", dev->bulk_in_filled, dev->bulk_in_copied); + + if (!available) { + /* + * all data has been used + * actual IO needs to be done + */ + /* it seems that requests for less than dev->bulk_in_size + * are not accepted + */ + rv = skel_do_read_io(dev, dev->bulk_in_size); + if (rv < 0) + goto exit; + else + goto retry; + } + + /* + * data is available - chunk tells us how much shall be copied + */ + + /* Condition dev->bulk_in_copied > 0 maybe will never happen. In case, + * signal the event and copy using the original procedure, i.e., copy + * first two bytes also + */ + + if (dev->bulk_in_copied) { + int j; + + for (j = 0 ; j < dev->bulk_in_filled ; j++) { + pr_alert("copy -> %x %zu %x\n", + j, dev->bulk_in_copied, dev->bulk_in_buffer[j]); + } + chunk = min(available, count); + memcpy(buffer, dev->bulk_in_buffer + dev->bulk_in_copied, chunk); + rv = chunk; + dev->bulk_in_copied += chunk; + + /* copy discarding first two bytes that contain ftdi chip status */ + + } else { + /* account for two bytes to be discarded */ + chunk = min(available, count + 2); + if (chunk < 2) { + pr_alert("BAD READ - chunk: %zu\n", chunk); + rv = -EIO; + goto exit; + } + + memcpy(buffer, dev->bulk_in_buffer + 2, chunk - 2); + rv = chunk; + dev->bulk_in_copied += chunk; + } + + /* + * if we are asked for more than we have, + * we start IO but don't wait + * + * No, no read ahead allowed; if the case, more data will be + * asked for by the lpvo_usb_gpib layer. + */ +// if (available < count) +// skel_do_read_io(dev, dev->bulk_in_size); + } else { + DIA_LOG(1, "no data - start read - copied: %zd.\n", dev->bulk_in_copied); + + /* no data in the buffer */ + rv = skel_do_read_io(dev, dev->bulk_in_size); + if (rv < 0) + goto exit; + else + goto retry; + } +exit: + mutex_unlock(&dev->io_mutex); + if (rv == 2) + goto restart; /* ftdi chip returns two status bytes after a latency anyhow */ + DIA_LOG(1, "exit with %d.\n", rv); + if (rv > 0) + return rv - 2; /* account for 2 discarded bytes in a valid buffer */ + return rv; +} + +/* + * write functions + */ + +static void skel_write_bulk_callback(struct urb *urb) +{ + struct usb_skel *dev; + unsigned long flags; + + dev = urb->context; + + /* sync/async unlink faults aren't errors */ + if (urb->status) { + if (!(urb->status == -ENOENT || + urb->status == -ECONNRESET || + urb->status == -ESHUTDOWN)) + dev_err(&dev->interface->dev, + "%s - nonzero write bulk status received: %d\n", + __func__, urb->status); + + spin_lock_irqsave(&dev->err_lock, flags); + dev->errors = urb->status; + spin_unlock_irqrestore(&dev->err_lock, flags); + } + + /* free up our allocated buffer */ + usb_free_coherent(urb->dev, urb->transfer_buffer_length, + urb->transfer_buffer, urb->transfer_dma); + up(&dev->limit_sem); +} + +/* + * skel_do_write() - write operations from lpvo_usb_gpib + */ + +static ssize_t skel_do_write(struct usb_skel *dev, const char *buffer, size_t count) +{ + int retval = 0; + struct urb *urb = NULL; + char *buf = NULL; + size_t writesize = min_t(size_t, count, (size_t)MAX_TRANSFER); + + /* verify that we actually have some data to write */ + if (count == 0) + goto exit; + + /* + * limit the number of URBs in flight to stop a user from using up all + * RAM + */ + /* Only one URB is used, because we can't have a pending write() and go on */ + +// if (!(file->f_flags & O_NONBLOCK)) { /* no NONBLOCK provided */ + if (down_interruptible(&dev->limit_sem)) { + retval = -ERESTARTSYS; + goto exit; + } +// } else { +// if (down_trylock(&dev->limit_sem)) { +// retval = -EAGAIN; +// goto exit; +// } +// } + + spin_lock_irq(&dev->err_lock); + retval = dev->errors; + if (retval < 0) { + /* any error is reported once */ + dev->errors = 0; + /* to preserve notifications about reset */ + retval = (retval == -EPIPE) ? retval : -EIO; + } + spin_unlock_irq(&dev->err_lock); + if (retval < 0) + goto error; + + /* create a urb, and a buffer for it, and copy the data to the urb */ + urb = usb_alloc_urb(0, GFP_KERNEL); + if (!urb) { + retval = -ENOMEM; + goto error; + } + + buf = usb_alloc_coherent(dev->udev, writesize, GFP_KERNEL, + &urb->transfer_dma); + if (!buf) { + retval = -ENOMEM; + goto error; + } + + memcpy(buf, buffer, count); + + /* this lock makes sure we don't submit URBs to gone devices */ + mutex_lock(&dev->io_mutex); + if (!dev->interface) { /* disconnect() was called */ + mutex_unlock(&dev->io_mutex); + retval = -ENODEV; + goto error; + } + + /* initialize the urb properly */ + usb_fill_bulk_urb(urb, dev->udev, + usb_sndbulkpipe(dev->udev, dev->bulk_out_endpoint_addr), + buf, writesize, skel_write_bulk_callback, dev); + urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP; + usb_anchor_urb(urb, &dev->submitted); + + /* send the data out the bulk port */ + retval = usb_submit_urb(urb, GFP_KERNEL); + mutex_unlock(&dev->io_mutex); + if (retval) { + dev_err(&dev->interface->dev, + "%s - failed submitting write urb, error %d\n", + __func__, retval); + goto error_unanchor; + } + + /* + * release our reference to this urb, the USB core will eventually free + * it entirely + */ + usb_free_urb(urb); + + return writesize; + +error_unanchor: + usb_unanchor_urb(urb); +error: + if (urb) { + usb_free_coherent(dev->udev, writesize, buf, urb->transfer_dma); + usb_free_urb(urb); + } + up(&dev->limit_sem); + +exit: + return retval; +} + +/* + * services for the user space devices + */ + +#if USER_DEVICE /* conditional compilation of user space device */ + +static int skel_flush(struct file *file, fl_owner_t id) +{ + struct usb_skel *dev; + int res; + + dev = file->private_data; + if (!dev) + return -ENODEV; + + /* wait for io to stop */ + mutex_lock(&dev->io_mutex); + skel_draw_down(dev); + + /* read out errors, leave subsequent opens a clean slate */ + spin_lock_irq(&dev->err_lock); + res = dev->errors ? (dev->errors == -EPIPE ? -EPIPE : -EIO) : 0; + dev->errors = 0; + spin_unlock_irq(&dev->err_lock); + + mutex_unlock(&dev->io_mutex); + + return res; +} + +static int skel_open(struct inode *inode, struct file *file) +{ + struct usb_skel *dev; + struct usb_interface *interface; + int subminor; + int retval = 0; + + subminor = iminor(inode); + + interface = usb_find_interface(&skel_driver, subminor); + if (!interface) { + pr_err("%s - error, can't find device for minor %d\n", + __func__, subminor); + retval = -ENODEV; + goto exit; + } + + dev = usb_get_intfdata(interface); + if (!dev) { + retval = -ENODEV; + goto exit; + } + + retval = usb_autopm_get_interface(interface); + if (retval) + goto exit; + + /* increment our usage count for the device */ + kref_get(&dev->kref); + + /* save our object in the file's private structure */ + file->private_data = dev; + +exit: + return retval; +} + +static int skel_release(struct inode *inode, struct file *file) +{ + struct usb_skel *dev; + + dev = file->private_data; + if (!dev) + return -ENODEV; + + /* allow the device to be autosuspended */ + mutex_lock(&dev->io_mutex); + if (dev->interface) + usb_autopm_put_interface(dev->interface); + mutex_unlock(&dev->io_mutex); + + /* decrement the count on our device */ + kref_put(&dev->kref, skel_delete); + return 0; +} + +/* + * user space access to read function + */ + +static ssize_t skel_read(struct file *file, char *buffer, size_t count, + loff_t *ppos) +{ + struct usb_skel *dev; + char *buf; + ssize_t rv; + + dev = file->private_data; + + buf = kmalloc(count, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + rv = skel_do_read(dev, buf, count); + + pr_alert("%s - return with %zu\n", __func__, rv); + + if (rv > 0) { + if (copy_to_user(buffer, buf, rv)) { + kfree(buf); + return -EFAULT; + } + } + kfree(buf); + return rv; +} + +/* + * user space access to write function + */ + +static ssize_t skel_write(struct file *file, const char *user_buffer, + size_t count, loff_t *ppos) +{ + struct usb_skel *dev; + char *buf; + ssize_t rv; + + dev = file->private_data; + + buf = kmalloc(count, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + if (copy_from_user(buf, user_buffer, count)) { + kfree(buf); + return -EFAULT; + } + + rv = skel_do_write(dev, buf, count); + kfree(buf); + return rv; +} +#endif + +static const struct file_operations skel_fops = { + .owner = THIS_MODULE, +#if USER_DEVICE + .read = skel_read, + .write = skel_write, + .open = skel_open, + .release = skel_release, + .flush = skel_flush, + .llseek = noop_llseek, +#endif +}; + +/* + * usb class driver info in order to get a minor number from the usb core, + * and to have the device registered with the driver core + */ +#if USER_DEVICE +static struct usb_class_driver skel_class = { + .name = "lpvo_raw%d", + .fops = &skel_fops, + .minor_base = USB_SKEL_MINOR_BASE, +}; +#endif + +static int skel_probe(struct usb_interface *interface, + const struct usb_device_id *id) +{ + struct usb_skel *dev; + struct usb_endpoint_descriptor *bulk_in, *bulk_out; + int retval; + char *device_path; + + mutex_init(&minors_lock); /* required for handling minor numbers table */ + + /* allocate memory for our device state and initialize it */ + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) + return -ENOMEM; + + kref_init(&dev->kref); + sema_init(&dev->limit_sem, WRITES_IN_FLIGHT); + mutex_init(&dev->io_mutex); + spin_lock_init(&dev->err_lock); + init_usb_anchor(&dev->submitted); + init_waitqueue_head(&dev->bulk_in_wait); + + dev->udev = usb_get_dev(interface_to_usbdev(interface)); + dev->interface = interface; + + /* set up the endpoint information */ + /* use only the first bulk-in and bulk-out endpoints */ + retval = usb_find_common_endpoints(interface->cur_altsetting, + &bulk_in, &bulk_out, NULL, NULL); + if (retval) { + dev_err(&interface->dev, + "Could not find both bulk-in and bulk-out endpoints\n"); + goto error; + } + + dev->bulk_in_size = usb_endpoint_maxp(bulk_in); + dev->bulk_in_endpoint_addr = bulk_in->bEndpointAddress; + dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL); + if (!dev->bulk_in_buffer) { + retval = -ENOMEM; + goto error; + } + dev->bulk_in_urb = usb_alloc_urb(0, GFP_KERNEL); + if (!dev->bulk_in_urb) { + retval = -ENOMEM; + goto error; + } + + dev->bulk_out_endpoint_addr = bulk_out->bEndpointAddress; + + /* save our data pointer in this interface device */ + usb_set_intfdata(interface, dev); + + /* let the world know */ + + device_path = kobject_get_path(&dev->udev->dev.kobj, GFP_KERNEL); + pr_alert("%s:%s - New lpvo_usb_device -> bus: %d dev: %d path: %s\n", NAME, __func__, + dev->udev->bus->busnum, dev->udev->devnum, device_path); + kfree(device_path); + +#if USER_DEVICE + /* we can register the device now, as it is ready */ + retval = usb_register_dev(interface, &skel_class); + if (retval) { + /* something prevented us from registering this driver */ + dev_err(&interface->dev, + "Not able to get a minor for this device.\n"); + usb_set_intfdata(interface, NULL); + goto error; + } + + /* let the user know what node this device is now attached to */ + dev_info(&interface->dev, + "lpvo_usb_gpib device now attached to lpvo_raw%d", + interface->minor); +#endif + + write_latency_timer(dev->udev); /* adjust the latency timer */ + + usb_gpib_init_module(interface); /* last, init the lpvo for this minor */ + + return 0; + +error: + /* this frees allocated memory */ + kref_put(&dev->kref, skel_delete); + + return retval; +} + +static void skel_disconnect(struct usb_interface *interface) +{ + struct usb_skel *dev; + int minor = interface->minor; + + usb_gpib_exit_module(minor); /* first, disactivate the lpvo */ + + dev = usb_get_intfdata(interface); + usb_set_intfdata(interface, NULL); + +#if USER_DEVICE + /* give back our minor */ + usb_deregister_dev(interface, &skel_class); +#endif + + /* prevent more I/O from starting */ + mutex_lock(&dev->io_mutex); + dev->interface = NULL; + mutex_unlock(&dev->io_mutex); + + usb_kill_anchored_urbs(&dev->submitted); + + /* decrement our usage count */ + kref_put(&dev->kref, skel_delete); + + dev_info(&interface->dev, "USB lpvo_raw #%d now disconnected", minor); +} + +static void skel_draw_down(struct usb_skel *dev) +{ + int time; + + time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000); + if (!time) + usb_kill_anchored_urbs(&dev->submitted); + usb_kill_urb(dev->bulk_in_urb); +} + +static int skel_suspend(struct usb_interface *intf, pm_message_t message) +{ + struct usb_skel *dev = usb_get_intfdata(intf); + + if (!dev) + return 0; + skel_draw_down(dev); + return 0; +} + +static int skel_resume(struct usb_interface *intf) +{ + return 0; +} + +static int skel_pre_reset(struct usb_interface *intf) +{ + struct usb_skel *dev = usb_get_intfdata(intf); + + mutex_lock(&dev->io_mutex); + skel_draw_down(dev); + + return 0; +} + +static int skel_post_reset(struct usb_interface *intf) +{ + struct usb_skel *dev = usb_get_intfdata(intf); + + /* we are sure no URBs are active - no locking needed */ + dev->errors = -EPIPE; + mutex_unlock(&dev->io_mutex); + + return 0; +} + +static struct usb_driver skel_driver = { + .name = NAME, + .probe = skel_probe, + .disconnect = skel_disconnect, + .suspend = skel_suspend, + .resume = skel_resume, + .pre_reset = skel_pre_reset, + .post_reset = skel_post_reset, + .id_table = skel_table, + .supports_autosuspend = 1, +}; + +module_usb_driver(skel_driver);