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[PATCH] USB: fix acm trouble with terminals
This patch fixes lost LF when ACM device is used with getty/login/bash, in case of a modem which takes calls. Signed-off-by: Pete Zaitcev <zaitcev@redhat.com> Signed-off-by: Oliver Neukum <oliver@neukum.name> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Oliver Neukum
Greg Kroah-Hartman
parent
d5926ae7a8
commit
884b600f63
2 changed files with 199 additions and 39 deletions
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@ -105,6 +105,111 @@ static int acm_ctrl_msg(struct acm *acm, int request, int value, void *buf, int
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#define acm_send_break(acm, ms) \
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acm_ctrl_msg(acm, USB_CDC_REQ_SEND_BREAK, ms, NULL, 0)
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/*
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* Write buffer management.
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* All of these assume proper locks taken by the caller.
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*/
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static int acm_wb_alloc(struct acm *acm)
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{
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int i, wbn;
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struct acm_wb *wb;
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wbn = acm->write_current;
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i = 0;
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for (;;) {
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wb = &acm->wb[wbn];
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if (!wb->use) {
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wb->use = 1;
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return wbn;
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}
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wbn = (wbn + 1) % ACM_NWB;
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if (++i >= ACM_NWB)
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return -1;
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}
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}
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static void acm_wb_free(struct acm *acm, int wbn)
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{
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acm->wb[wbn].use = 0;
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}
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static int acm_wb_is_avail(struct acm *acm)
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{
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int i, n;
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n = 0;
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for (i = 0; i < ACM_NWB; i++) {
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if (!acm->wb[i].use)
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n++;
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}
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return n;
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}
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static inline int acm_wb_is_used(struct acm *acm, int wbn)
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{
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return acm->wb[wbn].use;
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}
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/*
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* Finish write.
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*/
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static void acm_write_done(struct acm *acm)
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{
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unsigned long flags;
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int wbn;
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spin_lock_irqsave(&acm->write_lock, flags);
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acm->write_ready = 1;
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wbn = acm->write_current;
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acm_wb_free(acm, wbn);
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acm->write_current = (wbn + 1) % ACM_NWB;
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spin_unlock_irqrestore(&acm->write_lock, flags);
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}
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/*
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* Poke write.
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*/
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static int acm_write_start(struct acm *acm)
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{
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unsigned long flags;
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int wbn;
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struct acm_wb *wb;
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int rc;
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spin_lock_irqsave(&acm->write_lock, flags);
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if (!acm->dev) {
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spin_unlock_irqrestore(&acm->write_lock, flags);
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return -ENODEV;
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}
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if (!acm->write_ready) {
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spin_unlock_irqrestore(&acm->write_lock, flags);
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return 0; /* A white lie */
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}
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wbn = acm->write_current;
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if (!acm_wb_is_used(acm, wbn)) {
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spin_unlock_irqrestore(&acm->write_lock, flags);
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return 0;
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}
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wb = &acm->wb[wbn];
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acm->write_ready = 0;
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spin_unlock_irqrestore(&acm->write_lock, flags);
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acm->writeurb->transfer_buffer = wb->buf;
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acm->writeurb->transfer_dma = wb->dmah;
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acm->writeurb->transfer_buffer_length = wb->len;
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acm->writeurb->dev = acm->dev;
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if ((rc = usb_submit_urb(acm->writeurb, GFP_ATOMIC)) < 0) {
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dbg("usb_submit_urb(write bulk) failed: %d", rc);
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acm_write_done(acm);
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}
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return rc;
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}
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/*
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* Interrupt handlers for various ACM device responses
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*/
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@ -237,17 +342,13 @@ static void acm_rx_tasklet(unsigned long _acm)
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static void acm_write_bulk(struct urb *urb, struct pt_regs *regs)
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{
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struct acm *acm = (struct acm *)urb->context;
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dbg("Entering acm_write_bulk with status %d\n", urb->status);
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if (!ACM_READY(acm))
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goto out;
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if (urb->status)
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dbg("nonzero write bulk status received: %d", urb->status);
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schedule_work(&acm->work);
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out:
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acm->ready_for_write = 1;
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acm_write_done(acm);
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acm_write_start(acm);
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if (ACM_READY(acm))
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schedule_work(&acm->work);
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}
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static void acm_softint(void *private)
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@ -351,32 +452,33 @@ static int acm_tty_write(struct tty_struct *tty, const unsigned char *buf, int c
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{
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struct acm *acm = tty->driver_data;
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int stat;
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unsigned long flags;
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int wbn;
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struct acm_wb *wb;
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dbg("Entering acm_tty_write to write %d bytes,\n", count);
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if (!ACM_READY(acm))
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return -EINVAL;
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if (!acm->ready_for_write)
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return 0;
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if (!count)
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return 0;
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count = (count > acm->writesize) ? acm->writesize : count;
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dbg("Get %d bytes...", count);
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memcpy(acm->write_buffer, buf, count);
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dbg(" Successfully copied.\n");
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acm->writeurb->transfer_buffer_length = count;
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acm->writeurb->dev = acm->dev;
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acm->ready_for_write = 0;
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stat = usb_submit_urb(acm->writeurb, GFP_ATOMIC);
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if (stat < 0) {
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dbg("usb_submit_urb(write bulk) failed");
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acm->ready_for_write = 1;
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return stat;
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spin_lock_irqsave(&acm->write_lock, flags);
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if ((wbn = acm_wb_alloc(acm)) < 0) {
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spin_unlock_irqrestore(&acm->write_lock, flags);
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acm_write_start(acm);
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return 0;
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}
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wb = &acm->wb[wbn];
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count = (count > acm->writesize) ? acm->writesize : count;
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dbg("Get %d bytes...", count);
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memcpy(wb->buf, buf, count);
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wb->len = count;
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spin_unlock_irqrestore(&acm->write_lock, flags);
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if ((stat = acm_write_start(acm)) < 0)
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return stat;
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return count;
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}
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@ -385,7 +487,11 @@ static int acm_tty_write_room(struct tty_struct *tty)
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struct acm *acm = tty->driver_data;
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if (!ACM_READY(acm))
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return -EINVAL;
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return !acm->ready_for_write ? 0 : acm->writesize;
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/*
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* Do not let the line discipline to know that we have a reserve,
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* or it might get too enthusiastic.
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*/
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return (acm->write_ready && acm_wb_is_avail(acm)) ? acm->writesize : 0;
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}
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static int acm_tty_chars_in_buffer(struct tty_struct *tty)
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@ -393,7 +499,10 @@ static int acm_tty_chars_in_buffer(struct tty_struct *tty)
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struct acm *acm = tty->driver_data;
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if (!ACM_READY(acm))
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return -EINVAL;
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return !acm->ready_for_write ? acm->writeurb->transfer_buffer_length : 0;
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/*
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* This is inaccurate (overcounts), but it works.
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*/
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return (ACM_NWB - acm_wb_is_avail(acm)) * acm->writesize;
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}
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static void acm_tty_throttle(struct tty_struct *tty)
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@ -526,6 +635,39 @@ static void acm_tty_set_termios(struct tty_struct *tty, struct termios *termios_
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* USB probe and disconnect routines.
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*/
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/* Little helper: write buffers free */
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static void acm_write_buffers_free(struct acm *acm)
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{
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int i;
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struct acm_wb *wb;
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for (wb = &acm->wb[0], i = 0; i < ACM_NWB; i++, wb++) {
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usb_buffer_free(acm->dev, acm->writesize, wb->buf, wb->dmah);
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}
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}
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/* Little helper: write buffers allocate */
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static int acm_write_buffers_alloc(struct acm *acm)
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{
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int i;
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struct acm_wb *wb;
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for (wb = &acm->wb[0], i = 0; i < ACM_NWB; i++, wb++) {
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wb->buf = usb_buffer_alloc(acm->dev, acm->writesize, GFP_KERNEL,
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&wb->dmah);
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if (!wb->buf) {
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while (i != 0) {
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--i;
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--wb;
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usb_buffer_free(acm->dev, acm->writesize,
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wb->buf, wb->dmah);
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}
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return -ENOMEM;
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}
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}
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return 0;
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}
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static int acm_probe (struct usb_interface *intf,
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const struct usb_device_id *id)
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{
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@ -700,7 +842,8 @@ static int acm_probe (struct usb_interface *intf,
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acm->bh.data = (unsigned long) acm;
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INIT_WORK(&acm->work, acm_softint, acm);
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spin_lock_init(&acm->throttle_lock);
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acm->ready_for_write = 1;
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spin_lock_init(&acm->write_lock);
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acm->write_ready = 1;
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buf = usb_buffer_alloc(usb_dev, ctrlsize, GFP_KERNEL, &acm->ctrl_dma);
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if (!buf) {
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@ -716,12 +859,10 @@ static int acm_probe (struct usb_interface *intf,
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}
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acm->read_buffer = buf;
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buf = usb_buffer_alloc(usb_dev, acm->writesize, GFP_KERNEL, &acm->write_dma);
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if (!buf) {
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if (acm_write_buffers_alloc(acm) < 0) {
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dev_dbg(&intf->dev, "out of memory (write buffer alloc)\n");
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goto alloc_fail4;
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}
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acm->write_buffer = buf;
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acm->ctrlurb = usb_alloc_urb(0, GFP_KERNEL);
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if (!acm->ctrlurb) {
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@ -750,9 +891,9 @@ static int acm_probe (struct usb_interface *intf,
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acm->readurb->transfer_dma = acm->read_dma;
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usb_fill_bulk_urb(acm->writeurb, usb_dev, usb_sndbulkpipe(usb_dev, epwrite->bEndpointAddress),
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acm->write_buffer, acm->writesize, acm_write_bulk, acm);
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NULL, acm->writesize, acm_write_bulk, acm);
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acm->writeurb->transfer_flags |= URB_NO_FSBR | URB_NO_TRANSFER_DMA_MAP;
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acm->writeurb->transfer_dma = acm->write_dma;
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/* acm->writeurb->transfer_dma = 0; */
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dev_info(&intf->dev, "ttyACM%d: USB ACM device\n", minor);
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@ -775,7 +916,7 @@ static int acm_probe (struct usb_interface *intf,
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alloc_fail6:
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usb_free_urb(acm->ctrlurb);
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alloc_fail5:
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usb_buffer_free(usb_dev, acm->writesize, acm->write_buffer, acm->write_dma);
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acm_write_buffers_free(acm);
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alloc_fail4:
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usb_buffer_free(usb_dev, readsize, acm->read_buffer, acm->read_dma);
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alloc_fail3:
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@ -806,7 +947,7 @@ static void acm_disconnect(struct usb_interface *intf)
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flush_scheduled_work(); /* wait for acm_softint */
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usb_buffer_free(usb_dev, acm->writesize, acm->write_buffer, acm->write_dma);
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acm_write_buffers_free(acm);
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usb_buffer_free(usb_dev, acm->readsize, acm->read_buffer, acm->read_dma);
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usb_buffer_free(usb_dev, acm->ctrlsize, acm->ctrl_buffer, acm->ctrl_dma);
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@ -51,14 +51,34 @@
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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 accomodate 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.
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*/
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#define ACM_NWB 2
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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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};
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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_struct *tty; /* the corresponding tty */
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struct urb *ctrlurb, *readurb, *writeurb; /* urbs */
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u8 *ctrl_buffer, *read_buffer, *write_buffer; /* buffers of urbs */
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dma_addr_t ctrl_dma, read_dma, write_dma; /* dma handles of buffers */
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u8 *ctrl_buffer, *read_buffer; /* buffers of urbs */
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dma_addr_t ctrl_dma, read_dma; /* dma handles of buffers */
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struct acm_wb wb[ACM_NWB];
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int write_current; /* current write buffer */
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int write_used; /* number of non-empty write buffers */
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int write_ready; /* write urb is not running */
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spinlock_t write_lock;
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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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struct tasklet_struct bh; /* rx processing */
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@ -71,7 +91,6 @@ struct acm {
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unsigned int minor; /* acm minor number */
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unsigned char throttle; /* throttled by tty layer */
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unsigned char clocal; /* termios CLOCAL */
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unsigned char ready_for_write; /* write urb can be used */
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unsigned char resubmit_to_unthrottle; /* throtteling has disabled the read urb */
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unsigned int ctrl_caps; /* control capabilities from the class specific header */
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};
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