[PATCH] USB: Converting cdc acm to a ring queue
this patch by David converts the sending queue of the CDC ACM driver
to a queue of URBs. This is needed for quicker devices. Please apply.
Signed-Off-By: Oliver Neukum <oliver@neukum.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/usb/class/cdc-acm.c | 229 ++++++++++++++++++++++++++++++--------------
drivers/usb/class/cdc-acm.h | 33 +++++-
2 files changed, 185 insertions(+), 77 deletions(-)
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 1b47514..72936dc 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -6,6 +6,7 @@
* Copyright (c) 1999 Johannes Erdfelt <johannes@erdfelt.com>
* Copyright (c) 2000 Vojtech Pavlik <vojtech@suse.cz>
* Copyright (c) 2004 Oliver Neukum <oliver@neukum.name>
+ * Copyright (c) 2005 David Kubicek <dave@awk.cz>
*
* USB Abstract Control Model driver for USB modems and ISDN adapters
*
@@ -29,6 +30,7 @@
* config we want, sysadmin changes bConfigurationValue in sysfs.
* v0.23 - use softirq for rx processing, as needed by tty layer
* v0.24 - change probe method to evaluate CDC union descriptor
+ * v0.25 - downstream tasks paralelized to maximize throughput
*/
/*
@@ -63,14 +65,15 @@
#include <linux/usb_cdc.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>
+#include <linux/list.h>
#include "cdc-acm.h"
/*
* Version Information
*/
-#define DRIVER_VERSION "v0.23"
-#define DRIVER_AUTHOR "Armin Fuerst, Pavel Machek, Johannes Erdfelt, Vojtech Pavlik"
+#define DRIVER_VERSION "v0.25"
+#define DRIVER_AUTHOR "Armin Fuerst, Pavel Machek, Johannes Erdfelt, Vojtech Pavlik, David Kubicek"
#define DRIVER_DESC "USB Abstract Control Model driver for USB modems and ISDN adapters"
static struct usb_driver acm_driver;
@@ -284,7 +287,9 @@
/* data interface returns incoming bytes, or we got unthrottled */
static void acm_read_bulk(struct urb *urb, struct pt_regs *regs)
{
- struct acm *acm = urb->context;
+ struct acm_rb *buf;
+ struct acm_ru *rcv = urb->context;
+ struct acm *acm = rcv->instance;
dbg("Entering acm_read_bulk with status %d\n", urb->status);
if (!ACM_READY(acm))
@@ -293,49 +298,109 @@
if (urb->status)
dev_dbg(&acm->data->dev, "bulk rx status %d\n", urb->status);
- /* calling tty_flip_buffer_push() in_irq() isn't allowed */
- tasklet_schedule(&acm->bh);
+ buf = rcv->buffer;
+ buf->size = urb->actual_length;
+
+ spin_lock(&acm->read_lock);
+ list_add_tail(&rcv->list, &acm->spare_read_urbs);
+ list_add_tail(&buf->list, &acm->filled_read_bufs);
+ spin_unlock(&acm->read_lock);
+
+ tasklet_schedule(&acm->urb_task);
}
static void acm_rx_tasklet(unsigned long _acm)
{
struct acm *acm = (void *)_acm;
- struct urb *urb = acm->readurb;
+ struct acm_rb *buf;
struct tty_struct *tty = acm->tty;
- unsigned char *data = urb->transfer_buffer;
+ struct acm_ru *rcv;
+ //unsigned long flags;
int i = 0;
dbg("Entering acm_rx_tasklet");
- if (urb->actual_length > 0 && !acm->throttle) {
- for (i = 0; i < urb->actual_length && !acm->throttle; i++) {
- /* if we insert more than TTY_FLIPBUF_SIZE characters,
- * we drop them. */
- if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
- tty_flip_buffer_push(tty);
- }
- tty_insert_flip_char(tty, data[i], 0);
- }
- dbg("Handed %d bytes to tty layer", i+1);
- tty_flip_buffer_push(tty);
+ if (!ACM_READY(acm) || acm->throttle)
+ return;
+
+next_buffer:
+ spin_lock(&acm->read_lock);
+ if (list_empty(&acm->filled_read_bufs)) {
+ spin_unlock(&acm->read_lock);
+ goto urbs;
}
+ buf = list_entry(acm->filled_read_bufs.next,
+ struct acm_rb, list);
+ list_del(&buf->list);
+ spin_unlock(&acm->read_lock);
+
+ dbg("acm_rx_tasklet: procesing buf 0x%p, size = %d\n", buf, buf->size);
+
+ for (i = 0; i < buf->size && !acm->throttle; i++) {
+ /* if we insert more than TTY_FLIPBUF_SIZE characters,
+ we drop them. */
+ if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
+ tty_flip_buffer_push(tty);
+ }
+ tty_insert_flip_char(tty, buf->base[i], 0);
+ }
+ tty_flip_buffer_push(tty);
spin_lock(&acm->throttle_lock);
if (acm->throttle) {
dbg("Throtteling noticed");
- memmove(data, data + i, urb->actual_length - i);
- urb->actual_length -= i;
- acm->resubmit_to_unthrottle = 1;
+ memmove(buf->base, buf->base + i, buf->size - i);
+ buf->size -= i;
spin_unlock(&acm->throttle_lock);
+ spin_lock(&acm->read_lock);
+ list_add(&buf->list, &acm->filled_read_bufs);
+ spin_unlock(&acm->read_lock);
return;
}
spin_unlock(&acm->throttle_lock);
- urb->actual_length = 0;
- urb->dev = acm->dev;
+ spin_lock(&acm->read_lock);
+ list_add(&buf->list, &acm->spare_read_bufs);
+ spin_unlock(&acm->read_lock);
+ goto next_buffer;
- i = usb_submit_urb(urb, GFP_ATOMIC);
- if (i)
- dev_dbg(&acm->data->dev, "bulk rx resubmit %d\n", i);
+urbs:
+ while (!list_empty(&acm->spare_read_bufs)) {
+ spin_lock(&acm->read_lock);
+ if (list_empty(&acm->spare_read_urbs)) {
+ spin_unlock(&acm->read_lock);
+ return;
+ }
+ rcv = list_entry(acm->spare_read_urbs.next,
+ struct acm_ru, list);
+ list_del(&rcv->list);
+ spin_unlock(&acm->read_lock);
+
+ buf = list_entry(acm->spare_read_bufs.next,
+ struct acm_rb, list);
+ list_del(&buf->list);
+
+ rcv->buffer = buf;
+
+ usb_fill_bulk_urb(rcv->urb, acm->dev,
+ acm->rx_endpoint,
+ buf->base,
+ acm->readsize,
+ acm_read_bulk, rcv);
+ rcv->urb->transfer_dma = buf->dma;
+ rcv->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+ dbg("acm_rx_tasklet: sending urb 0x%p, rcv 0x%p, buf 0x%p\n", rcv->urb, rcv, buf);
+
+ /* This shouldn't kill the driver as unsuccessful URBs are returned to the
+ free-urbs-pool and resubmited ASAP */
+ if (usb_submit_urb(rcv->urb, GFP_ATOMIC) < 0) {
+ list_add(&buf->list, &acm->spare_read_bufs);
+ spin_lock(&acm->read_lock);
+ list_add(&rcv->list, &acm->spare_read_urbs);
+ spin_unlock(&acm->read_lock);
+ return;
+ }
+ }
}
/* data interface wrote those outgoing bytes */
@@ -369,6 +434,7 @@
{
struct acm *acm;
int rv = -EINVAL;
+ int i;
dbg("Entering acm_tty_open.\n");
down(&open_sem);
@@ -382,7 +448,9 @@
tty->driver_data = acm;
acm->tty = tty;
-
+ /* force low_latency on so that our tty_push actually forces the data through,
+ otherwise it is scheduled, and with high data rates data can get lost. */
+ tty->low_latency = 1;
if (acm->used++) {
goto done;
@@ -394,18 +462,20 @@
goto bail_out;
}
- acm->readurb->dev = acm->dev;
- if (usb_submit_urb(acm->readurb, GFP_KERNEL)) {
- dbg("usb_submit_urb(read bulk) failed");
- goto bail_out_and_unlink;
- }
-
if (0 > acm_set_control(acm, acm->ctrlout = ACM_CTRL_DTR | ACM_CTRL_RTS))
goto full_bailout;
- /* force low_latency on so that our tty_push actually forces the data through,
- otherwise it is scheduled, and with high data rates data can get lost. */
- tty->low_latency = 1;
+ INIT_LIST_HEAD(&acm->spare_read_urbs);
+ INIT_LIST_HEAD(&acm->spare_read_bufs);
+ INIT_LIST_HEAD(&acm->filled_read_bufs);
+ for (i = 0; i < ACM_NRU; i++) {
+ list_add(&(acm->ru[i].list), &acm->spare_read_urbs);
+ }
+ for (i = 0; i < ACM_NRB; i++) {
+ list_add(&(acm->rb[i].list), &acm->spare_read_bufs);
+ }
+
+ tasklet_schedule(&acm->urb_task);
done:
err_out:
@@ -413,8 +483,6 @@
return rv;
full_bailout:
- usb_kill_urb(acm->readurb);
-bail_out_and_unlink:
usb_kill_urb(acm->ctrlurb);
bail_out:
acm->used--;
@@ -424,18 +492,22 @@
static void acm_tty_unregister(struct acm *acm)
{
+ int i;
+
tty_unregister_device(acm_tty_driver, acm->minor);
usb_put_intf(acm->control);
acm_table[acm->minor] = NULL;
usb_free_urb(acm->ctrlurb);
- usb_free_urb(acm->readurb);
usb_free_urb(acm->writeurb);
+ for (i = 0; i < ACM_NRU; i++)
+ usb_free_urb(acm->ru[i].urb);
kfree(acm);
}
static void acm_tty_close(struct tty_struct *tty, struct file *filp)
{
struct acm *acm = tty->driver_data;
+ int i;
if (!acm || !acm->used)
return;
@@ -446,7 +518,8 @@
acm_set_control(acm, acm->ctrlout = 0);
usb_kill_urb(acm->ctrlurb);
usb_kill_urb(acm->writeurb);
- usb_kill_urb(acm->readurb);
+ for (i = 0; i < ACM_NRU; i++)
+ usb_kill_urb(acm->ru[i].urb);
} else
acm_tty_unregister(acm);
}
@@ -528,10 +601,7 @@
spin_lock_bh(&acm->throttle_lock);
acm->throttle = 0;
spin_unlock_bh(&acm->throttle_lock);
- if (acm->resubmit_to_unthrottle) {
- acm->resubmit_to_unthrottle = 0;
- acm_read_bulk(acm->readurb, NULL);
- }
+ tasklet_schedule(&acm->urb_task);
}
static void acm_tty_break_ctl(struct tty_struct *tty, int state)
@@ -694,6 +764,7 @@
int call_interface_num = -1;
int data_interface_num;
unsigned long quirks;
+ int i;
/* handle quirks deadly to normal probing*/
quirks = (unsigned long)id->driver_info;
@@ -833,7 +904,7 @@
}
ctrlsize = le16_to_cpu(epctrl->wMaxPacketSize);
- readsize = le16_to_cpu(epread->wMaxPacketSize);
+ readsize = le16_to_cpu(epread->wMaxPacketSize)*2;
acm->writesize = le16_to_cpu(epwrite->wMaxPacketSize);
acm->control = control_interface;
acm->data = data_interface;
@@ -842,12 +913,14 @@
acm->ctrl_caps = ac_management_function;
acm->ctrlsize = ctrlsize;
acm->readsize = readsize;
- acm->bh.func = acm_rx_tasklet;
- acm->bh.data = (unsigned long) acm;
+ acm->urb_task.func = acm_rx_tasklet;
+ acm->urb_task.data = (unsigned long) acm;
INIT_WORK(&acm->work, acm_softint, acm);
spin_lock_init(&acm->throttle_lock);
spin_lock_init(&acm->write_lock);
+ spin_lock_init(&acm->read_lock);
acm->write_ready = 1;
+ acm->rx_endpoint = usb_rcvbulkpipe(usb_dev, epread->bEndpointAddress);
buf = usb_buffer_alloc(usb_dev, ctrlsize, GFP_KERNEL, &acm->ctrl_dma);
if (!buf) {
@@ -856,13 +929,6 @@
}
acm->ctrl_buffer = buf;
- buf = usb_buffer_alloc(usb_dev, readsize, GFP_KERNEL, &acm->read_dma);
- if (!buf) {
- dev_dbg(&intf->dev, "out of memory (read buffer alloc)\n");
- goto alloc_fail3;
- }
- acm->read_buffer = buf;
-
if (acm_write_buffers_alloc(acm) < 0) {
dev_dbg(&intf->dev, "out of memory (write buffer alloc)\n");
goto alloc_fail4;
@@ -873,10 +939,25 @@
dev_dbg(&intf->dev, "out of memory (ctrlurb kmalloc)\n");
goto alloc_fail5;
}
- acm->readurb = usb_alloc_urb(0, GFP_KERNEL);
- if (!acm->readurb) {
- dev_dbg(&intf->dev, "out of memory (readurb kmalloc)\n");
- goto alloc_fail6;
+ for (i = 0; i < ACM_NRU; i++) {
+ struct acm_ru *rcv = &(acm->ru[i]);
+
+ if (!(rcv->urb = usb_alloc_urb(0, GFP_KERNEL))) {
+ dev_dbg(&intf->dev, "out of memory (read urbs usb_alloc_urb)\n");
+ goto alloc_fail7;
+ }
+
+ rcv->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+ rcv->instance = acm;
+ }
+ for (i = 0; i < ACM_NRB; i++) {
+ struct acm_rb *buf = &(acm->rb[i]);
+
+ // Using usb_buffer_alloc instead of kmalloc as Oliver suggested
+ if (!(buf->base = usb_buffer_alloc(acm->dev, readsize, GFP_KERNEL, &buf->dma))) {
+ dev_dbg(&intf->dev, "out of memory (read bufs usb_buffer_alloc)\n");
+ goto alloc_fail7;
+ }
}
acm->writeurb = usb_alloc_urb(0, GFP_KERNEL);
if (!acm->writeurb) {
@@ -889,15 +970,9 @@
acm->ctrlurb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
acm->ctrlurb->transfer_dma = acm->ctrl_dma;
- usb_fill_bulk_urb(acm->readurb, usb_dev, usb_rcvbulkpipe(usb_dev, epread->bEndpointAddress),
- acm->read_buffer, readsize, acm_read_bulk, acm);
- acm->readurb->transfer_flags |= URB_NO_FSBR | URB_NO_TRANSFER_DMA_MAP;
- acm->readurb->transfer_dma = acm->read_dma;
-
usb_fill_bulk_urb(acm->writeurb, usb_dev, usb_sndbulkpipe(usb_dev, epwrite->bEndpointAddress),
NULL, acm->writesize, acm_write_bulk, acm);
acm->writeurb->transfer_flags |= URB_NO_FSBR | URB_NO_TRANSFER_DMA_MAP;
- /* acm->writeurb->transfer_dma = 0; */
dev_info(&intf->dev, "ttyACM%d: USB ACM device\n", minor);
@@ -917,14 +992,14 @@
return 0;
alloc_fail7:
- usb_free_urb(acm->readurb);
-alloc_fail6:
+ for (i = 0; i < ACM_NRB; i++)
+ usb_buffer_free(usb_dev, acm->readsize, acm->rb[i].base, acm->rb[i].dma);
+ for (i = 0; i < ACM_NRU; i++)
+ usb_free_urb(acm->ru[i].urb);
usb_free_urb(acm->ctrlurb);
alloc_fail5:
acm_write_buffers_free(acm);
alloc_fail4:
- usb_buffer_free(usb_dev, readsize, acm->read_buffer, acm->read_dma);
-alloc_fail3:
usb_buffer_free(usb_dev, ctrlsize, acm->ctrl_buffer, acm->ctrl_dma);
alloc_fail2:
kfree(acm);
@@ -936,6 +1011,7 @@
{
struct acm *acm = usb_get_intfdata (intf);
struct usb_device *usb_dev = interface_to_usbdev(intf);
+ int i;
if (!acm || !acm->dev) {
dbg("disconnect on nonexisting interface");
@@ -946,15 +1022,24 @@
acm->dev = NULL;
usb_set_intfdata (intf, NULL);
+ tasklet_disable(&acm->urb_task);
+
usb_kill_urb(acm->ctrlurb);
- usb_kill_urb(acm->readurb);
usb_kill_urb(acm->writeurb);
+ for (i = 0; i < ACM_NRU; i++)
+ usb_kill_urb(acm->ru[i].urb);
+
+ INIT_LIST_HEAD(&acm->filled_read_bufs);
+ INIT_LIST_HEAD(&acm->spare_read_bufs);
+
+ tasklet_enable(&acm->urb_task);
flush_scheduled_work(); /* wait for acm_softint */
acm_write_buffers_free(acm);
- usb_buffer_free(usb_dev, acm->readsize, acm->read_buffer, acm->read_dma);
usb_buffer_free(usb_dev, acm->ctrlsize, acm->ctrl_buffer, acm->ctrl_dma);
+ for (i = 0; i < ACM_NRB; i++)
+ usb_buffer_free(usb_dev, acm->readsize, acm->rb[i].base, acm->rb[i].dma);
usb_driver_release_interface(&acm_driver, acm->data);
diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
index 963a5df..fd2aaccd 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -59,6 +59,9 @@
* when processing onlcr, so we only need 2 buffers.
*/
#define ACM_NWB 2
+#define ACM_NRU 16
+#define ACM_NRB 16
+
struct acm_wb {
unsigned char *buf;
dma_addr_t dmah;
@@ -66,22 +69,43 @@
int use;
};
+struct acm_rb {
+ struct list_head list;
+ int size;
+ unsigned char *base;
+ dma_addr_t dma;
+};
+
+struct acm_ru {
+ struct list_head list;
+ struct acm_rb *buffer;
+ struct urb *urb;
+ struct acm *instance;
+};
+
struct acm {
struct usb_device *dev; /* the corresponding usb device */
struct usb_interface *control; /* control interface */
struct usb_interface *data; /* data interface */
struct tty_struct *tty; /* the corresponding tty */
- struct urb *ctrlurb, *readurb, *writeurb; /* urbs */
- u8 *ctrl_buffer, *read_buffer; /* buffers of urbs */
- dma_addr_t ctrl_dma, read_dma; /* dma handles of buffers */
+ struct urb *ctrlurb, *writeurb; /* urbs */
+ u8 *ctrl_buffer; /* buffers of urbs */
+ dma_addr_t ctrl_dma; /* dma handles of buffers */
struct acm_wb wb[ACM_NWB];
+ struct acm_ru ru[ACM_NRU];
+ struct acm_rb rb[ACM_NRB];
+ int rx_endpoint;
+ spinlock_t read_lock;
+ struct list_head spare_read_urbs;
+ struct list_head spare_read_bufs;
+ struct list_head filled_read_bufs;
int write_current; /* current write buffer */
int write_used; /* number of non-empty write buffers */
int write_ready; /* write urb is not running */
spinlock_t write_lock;
struct usb_cdc_line_coding line; /* bits, stop, parity */
struct work_struct work; /* work queue entry for line discipline waking up */
- struct tasklet_struct bh; /* rx processing */
+ struct tasklet_struct urb_task; /* rx processing */
spinlock_t throttle_lock; /* synchronize throtteling and read callback */
unsigned int ctrlin; /* input control lines (DCD, DSR, RI, break, overruns) */
unsigned int ctrlout; /* output control lines (DTR, RTS) */
@@ -91,7 +115,6 @@
unsigned int minor; /* acm minor number */
unsigned char throttle; /* throttled by tty layer */
unsigned char clocal; /* termios CLOCAL */
- unsigned char resubmit_to_unthrottle; /* throtteling has disabled the read urb */
unsigned int ctrl_caps; /* control capabilities from the class specific header */
};
