libusbhost: new library for Linux USB host support.
Supports access to Linux usbdevfs on both device and Linux host.
Change-Id: Ie88a5193be3ee715792b10b34b3da32ffc4ca57b
Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/libusbhost/usbhost.c b/libusbhost/usbhost.c
new file mode 100644
index 0000000..d2eaf0c
--- /dev/null
+++ b/libusbhost/usbhost.c
@@ -0,0 +1,456 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/inotify.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <ctype.h>
+#include <pthread.h>
+
+#include <linux/usbdevice_fs.h>
+#include <linux/version.h>
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 20)
+#include <linux/usb/ch9.h>
+#else
+#include <linux/usb_ch9.h>
+#endif
+#include <asm/byteorder.h>
+
+#include "usbhost/usbhost.h"
+
+#define USB_FS_DIR "/dev/bus/usb"
+
+#if 0
+#define D printf
+#else
+#define D(...)
+#endif
+
+struct usb_device {
+ char dev_name[64];
+ unsigned char desc[256];
+ int desc_length;
+ int fd;
+ int writeable;
+};
+
+struct usb_endpoint
+{
+ struct usb_device *dev;
+ struct usb_endpoint_descriptor desc;
+ struct usbdevfs_urb urb;
+};
+
+static usb_device_added_cb s_added_cb;
+static usb_device_removed_cb s_removed_cb;
+
+static inline int badname(const char *name)
+{
+ while(*name) {
+ if(!isdigit(*name++)) return 1;
+ }
+ return 0;
+}
+
+static void find_existing_devices()
+{
+ char busname[32], devname[32];
+ DIR *busdir , *devdir ;
+ struct dirent *de;
+
+ busdir = opendir(USB_FS_DIR);
+ if(busdir == 0) return;
+
+ while((de = readdir(busdir)) != 0) {
+ if(badname(de->d_name)) continue;
+
+ snprintf(busname, sizeof busname, "%s/%s", USB_FS_DIR, de->d_name);
+ devdir = opendir(busname);
+ if(devdir == 0) continue;
+
+ while((de = readdir(devdir))) {
+ if(badname(de->d_name)) continue;
+
+ snprintf(devname, sizeof devname, "%s/%s", busname, de->d_name);
+ s_added_cb(devname);
+ } // end of devdir while
+ closedir(devdir);
+ } //end of busdir while
+ closedir(busdir);
+}
+
+static void* device_discovery_thread(void* unused)
+{
+ struct inotify_event* event;
+ char event_buf[512];
+ char path[100];
+ int i, fd, ret;
+ int wd, wds[10];
+ int wd_count = sizeof(wds) / sizeof(wds[0]);
+
+ D("Created device discovery thread\n");
+
+ fd = inotify_init();
+ if (fd < 0) {
+ fprintf(stderr, "inotify_init failed\n");
+ return NULL;
+ }
+
+ /* watch for files added and deleted within USB_FS_DIR */
+ memset(wds, 0, sizeof(wds));
+ /* watch the root for new subdirectories */
+ wds[0] = inotify_add_watch(fd, USB_FS_DIR, IN_CREATE | IN_DELETE);
+ if (wds[0] < 0) {
+ fprintf(stderr, "inotify_add_watch failed\n");
+ return NULL;
+ }
+
+ /* watch existing subdirectories of USB_FS_DIR */
+ for (i = 1; i < wd_count; i++) {
+ snprintf(path, sizeof(path), "%s/%03d", USB_FS_DIR, i);
+ ret = inotify_add_watch(fd, path, IN_CREATE | IN_DELETE);
+ if (ret > 0)
+ wds[i] = ret;
+ }
+
+ /* check for existing devices first, after we have inotify set up */
+ if (s_added_cb)
+ find_existing_devices();
+
+ while (1) {
+ ret = read(fd, event_buf, sizeof(event_buf));
+ if (ret >= (int)sizeof(struct inotify_event)) {
+ event = (struct inotify_event *)event_buf;
+ wd = event->wd;
+ if (wd == wds[0]) {
+ i = atoi(event->name);
+ snprintf(path, sizeof(path), "%s/%s", USB_FS_DIR, event->name);
+ D("new subdirectory %s: index: %d\n", path, i);
+ if (i > 0 && i < wd_count) {
+ ret = inotify_add_watch(fd, path, IN_CREATE | IN_DELETE);
+ if (ret > 0)
+ wds[i] = ret;
+ }
+ } else {
+ for (i = 1; i < wd_count; i++) {
+ if (wd == wds[i]) {
+ snprintf(path, sizeof(path), "%s/%03d/%s", USB_FS_DIR, i, event->name);
+ if (event->mask == IN_CREATE) {
+ D("new device %s\n", path);
+ if (s_added_cb)
+ s_added_cb(path);
+ } else if (event->mask == IN_DELETE) {
+ D("gone device %s\n", path);
+ if (s_removed_cb)
+ s_removed_cb(path);
+ }
+ }
+ }
+ }
+ }
+ }
+ return NULL;
+}
+
+int usb_host_init(usb_device_added_cb added_cb, usb_device_removed_cb removed_cb)
+{
+ pthread_t tid;
+
+ s_added_cb = added_cb;
+ s_removed_cb = removed_cb;
+
+ if (added_cb || removed_cb) {
+ pthread_attr_t attr;
+
+ pthread_attr_init(&attr);
+ pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+ return pthread_create(&tid, &attr, device_discovery_thread, NULL);
+ }
+ else
+ return 0;
+}
+
+struct usb_device *usb_device_open(const char *dev_name)
+{
+ struct usb_device *device = calloc(1, sizeof(struct usb_device));
+ int fd, length, did_retry = 0;
+
+ strcpy(device->dev_name, dev_name);
+ device->writeable = 1;
+
+retry:
+ fd = open(dev_name, O_RDWR);
+ if (fd < 0) {
+ /* if we fail, see if have read-only access */
+ fd = open(dev_name, O_RDONLY);
+ if (fd < 0 && errno == EACCES && !did_retry) {
+ /* work around race condition between inotify and permissions management */
+ sleep(1);
+ did_retry = 1;
+ goto retry;
+ }
+
+ if (fd < 0) goto fail;
+ device->writeable = 0;
+ D("[ usb open read-only %s fd = %d]\n", dev_name, fd);
+ }
+
+ length = read(fd, device->desc, sizeof(device->desc));
+ if (length < 0)
+ goto fail;
+
+ device->fd = fd;
+ device->desc_length = length;
+ return device;
+fail:
+ close(fd);
+ free(device);
+ return NULL;
+}
+
+void usb_device_close(struct usb_device *device)
+{
+ close(device->fd);
+ free(device);
+}
+
+const char* usb_device_get_name(struct usb_device *device)
+{
+ return device->dev_name;
+}
+
+uint16_t usb_device_get_vendor_id(struct usb_device *device)
+{
+ struct usb_device_descriptor* desc = (struct usb_device_descriptor*)device->desc;
+ return __le16_to_cpu(desc->idVendor);
+}
+
+uint16_t usb_device_get_product_id(struct usb_device *device)
+{
+ struct usb_device_descriptor* desc = (struct usb_device_descriptor*)device->desc;
+ return __le16_to_cpu(desc->idProduct);
+}
+
+char* usb_device_get_string(struct usb_device *device, int id)
+{
+ char string[256];
+ struct usbdevfs_ctrltransfer ctrl;
+ __u16 buffer[128];
+ __u16 languages[128];
+ int i, result;
+ int languageCount = 0;
+
+ string[0] = 0;
+
+ // reading the string requires read/write permission
+ if (!device->writeable) {
+ int fd = open(device->dev_name, O_RDWR);
+ if (fd > 0) {
+ close(device->fd);
+ device->fd = fd;
+ device->writeable = 1;
+ } else {
+ return NULL;
+ }
+ }
+
+ memset(languages, 0, sizeof(languages));
+ memset(&ctrl, 0, sizeof(ctrl));
+
+ // read list of supported languages
+ ctrl.bRequestType = USB_DIR_IN|USB_TYPE_STANDARD|USB_RECIP_DEVICE;
+ ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
+ ctrl.wValue = (USB_DT_STRING << 8) | 0;
+ ctrl.wIndex = 0;
+ ctrl.wLength = sizeof(languages);
+ ctrl.data = languages;
+
+ result = ioctl(device->fd, USBDEVFS_CONTROL, &ctrl);
+ if (result > 0)
+ languageCount = (result - 2) / 2;
+
+ for (i = 1; i <= languageCount; i++) {
+ memset(buffer, 0, sizeof(buffer));
+ memset(&ctrl, 0, sizeof(ctrl));
+
+ ctrl.bRequestType = USB_DIR_IN|USB_TYPE_STANDARD|USB_RECIP_DEVICE;
+ ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
+ ctrl.wValue = (USB_DT_STRING << 8) | id;
+ ctrl.wIndex = languages[i];
+ ctrl.wLength = sizeof(buffer);
+ ctrl.data = buffer;
+
+ result = ioctl(device->fd, USBDEVFS_CONTROL, &ctrl);
+ if (result > 0) {
+ int i;
+ // skip first word, and copy the rest to the string, changing shorts to bytes.
+ result /= 2;
+ for (i = 1; i < result; i++)
+ string[i - 1] = buffer[i];
+ string[i - 1] = 0;
+ return strdup(string);
+ }
+ }
+
+ return NULL;
+}
+
+char* usb_device_get_manufacturer_name(struct usb_device *device)
+{
+ struct usb_device_descriptor *desc = (struct usb_device_descriptor *)device->desc;
+
+ if (desc->iManufacturer)
+ return usb_device_get_string(device, desc->iManufacturer);
+ else
+ return NULL;
+}
+
+char* usb_device_get_product_name(struct usb_device *device)
+{
+ struct usb_device_descriptor *desc = (struct usb_device_descriptor *)device->desc;
+
+ if (desc->iProduct)
+ return usb_device_get_string(device, desc->iProduct);
+ else
+ return NULL;
+}
+
+char* usb_device_get_serial(struct usb_device *device)
+{
+ struct usb_device_descriptor *desc = (struct usb_device_descriptor *)device->desc;
+
+ if (desc->iSerialNumber)
+ return usb_device_get_string(device, desc->iSerialNumber);
+ else
+ return NULL;
+}
+
+int usb_device_is_writeable(struct usb_device *device)
+{
+ return device->writeable;
+}
+
+void usb_descriptor_iter_init(struct usb_device *device, struct usb_descriptor_iter *iter)
+{
+ iter->config = device->desc;
+ iter->config_end = device->desc + device->desc_length;
+ iter->curr_desc = device->desc;
+}
+
+struct usb_descriptor_header *usb_descriptor_iter_next(struct usb_descriptor_iter *iter)
+{
+ struct usb_descriptor_header* next;
+ if (iter->curr_desc >= iter->config_end)
+ return NULL;
+ next = (struct usb_descriptor_header*)iter->curr_desc;
+ iter->curr_desc += next->bLength;
+ return next;
+}
+
+int usb_device_claim_interface(struct usb_device *device, unsigned int interface)
+{
+ return ioctl(device->fd, USBDEVFS_CLAIMINTERFACE, &interface);
+}
+
+int usb_device_release_interface(struct usb_device *device, unsigned int interface)
+{
+ return ioctl(device->fd, USBDEVFS_RELEASEINTERFACE, &interface);
+}
+
+struct usb_endpoint *usb_endpoint_open(struct usb_device *dev,
+ const struct usb_endpoint_descriptor *desc)
+{
+ struct usb_endpoint *ep = calloc(1, sizeof(struct usb_endpoint));
+ memcpy(&ep->desc, desc, sizeof(ep->desc));
+ ep->dev = dev;
+ return ep;
+}
+
+void usb_endpoint_close(struct usb_endpoint *ep)
+{
+ // cancel IO here?
+ free(ep);
+}
+
+int usb_endpoint_queue(struct usb_endpoint *ep, void *data, int len)
+{
+ struct usbdevfs_urb *urb = &ep->urb;
+ int res;
+
+ D("usb_endpoint_queue\n");
+ memset(urb, 0, sizeof(*urb));
+ urb->type = USBDEVFS_URB_TYPE_BULK;
+ urb->endpoint = ep->desc.bEndpointAddress;
+ urb->status = -1;
+ urb->buffer = data;
+ urb->buffer_length = len;
+
+ do {
+ res = ioctl(ep->dev->fd, USBDEVFS_SUBMITURB, urb);
+ } while((res < 0) && (errno == EINTR));
+
+ return res;
+}
+
+int usb_endpoint_wait(struct usb_device *dev, int *out_ep_num)
+{
+ struct usbdevfs_urb *out = NULL;
+ int res;
+
+ while (1) {
+ res = ioctl(dev->fd, USBDEVFS_REAPURB, &out);
+ D("USBDEVFS_REAPURB returned %d\n", res);
+ if (res < 0) {
+ if(errno == EINTR) {
+ continue;
+ }
+ D("[ reap urb - error ]\n");
+ *out_ep_num = -1;
+ } else {
+ D("[ urb @%p status = %d, actual = %d ]\n",
+ out, out->status, out->actual_length);
+ res = out->actual_length;
+ *out_ep_num = out->endpoint;
+ }
+ break;
+ }
+ return res;
+}
+
+int usb_endpoint_cancel(struct usb_endpoint *ep)
+{
+ return ioctl(ep->dev->fd, USBDEVFS_DISCARDURB, &ep->urb);
+}
+
+int usb_endpoint_number(struct usb_endpoint *ep)
+{
+ return ep->desc.bEndpointAddress;
+}
+
+int usb_endpoint_max_packet(struct usb_endpoint *ep)
+{
+ return __le16_to_cpu(ep->desc.wMaxPacketSize);
+}
+