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>

2 files changed, 497 insertions, 0 deletions

diff --git a/libusbhost/Android.mk b/libusbhost/Android.mk
new file mode 100644
index 0000000..c8c8758
--- /dev/null
+++ b/libusbhost/Android.mk
@@ -0,0 +1,41 @@
+#
+# 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.
+#
+
+LOCAL_PATH := $(my-dir)
+
+# Static library for Linux host
+# ========================================================
+
+ifeq ($(HOST_OS),linux)
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := libusbhost
+LOCAL_SRC_FILES := usbhost.c
+
+include $(BUILD_HOST_STATIC_LIBRARY)
+
+endif
+
+# Static library for target
+# ========================================================
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := libusbhost
+LOCAL_SRC_FILES := usbhost.c
+
+include $(BUILD_STATIC_LIBRARY)
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);
+}
+