// SPDX-License-Identifier: GPL-2.0+
/*
* trans_usbg.c - USB peripheral usb9pfs configuration driver and transport.
*
* Copyright (C) 2024 Michael Grzeschik <[email protected]>
*/
/* Gadget usb9pfs only needs two bulk endpoints, and will use the usb9pfs
* transport to mount host exported filesystem via usb gadget.
*/
/* +--------------------------+ | +--------------------------+
* | 9PFS mounting client | | | 9PFS exporting server |
* SW | | | | |
* | (this:trans_usbg) | | |(e.g. diod or nfs-ganesha)|
* +-------------^------------+ | +-------------^------------+
* | | |
* ------------------|------------------------------------|-------------
* | | |
* +-------------v------------+ | +-------------v------------+
* | | | | |
* HW | USB Device Controller <---------> USB Host Controller |
* | | | | |
* +--------------------------+ | +--------------------------+
*/
#include <linux/cleanup.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/usb/composite.h>
#include <linux/usb/func_utils.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include <net/9p/transport.h>
#define DEFAULT_BUFLEN 16384
struct f_usb9pfs {
struct p9_client *client;
/* 9p request lock for en/dequeue */
spinlock_t lock;
struct usb_request *in_req;
struct usb_request *out_req;
struct usb_ep *in_ep;
struct usb_ep *out_ep;
struct completion send;
struct completion received;
unsigned int buflen;
struct usb_function function;
};
static inline struct f_usb9pfs *func_to_usb9pfs(struct usb_function *f)
{
return container_of(f, struct f_usb9pfs, function);
}
struct f_usb9pfs_opts {
struct usb_function_instance func_inst;
unsigned int buflen;
struct f_usb9pfs_dev *dev;
/* Read/write access to configfs attributes is handled by configfs.
*
* This is to protect the data from concurrent access by read/write
* and create symlink/remove symlink.
*/
struct mutex lock;
int refcnt;
};
struct f_usb9pfs_dev {
struct f_usb9pfs *usb9pfs;
struct f_usb9pfs_opts *opts;
char tag[41];
bool inuse;
struct list_head usb9pfs_instance;
};
static DEFINE_MUTEX(usb9pfs_lock);
static struct list_head usbg_instance_list;
static int usb9pfs_queue_tx(struct f_usb9pfs *usb9pfs, struct p9_req_t *p9_tx_req,
gfp_t gfp_flags)
{
struct usb_composite_dev *cdev = usb9pfs->function.config->cdev;
struct usb_request *req = usb9pfs->in_req;
int ret;
if (!(p9_tx_req->tc.size % usb9pfs->in_ep->maxpacket))
req->zero = 1;
req->buf = p9_tx_req->tc.sdata;
req->length = p9_tx_req->tc.size;
req->context = p9_tx_req;
dev_dbg(&cdev->gadget->dev, "%s usb9pfs send --> %d/%d, zero: %d\n",
usb9pfs->in_ep->name, req->actual, req->length, req->zero);
ret = usb_ep_queue(usb9pfs->in_ep, req, gfp_flags);
if (ret)
req->context = NULL;
dev_dbg(&cdev->gadget->dev, "tx submit --> %d\n", ret);
return ret;
}
static int usb9pfs_queue_rx(struct f_usb9pfs *usb9pfs, struct usb_request *req,
gfp_t gfp_flags)
{
struct usb_composite_dev *cdev = usb9pfs->function.config->cdev;
int ret;
ret = usb_ep_queue(usb9pfs->out_ep, req, gfp_flags);
dev_dbg(&cdev->gadget->dev, "rx submit --> %d\n", ret);
return ret;
}
static int usb9pfs_transmit(struct f_usb9pfs *usb9pfs, struct p9_req_t *p9_req)
{
int ret = 0;
guard(spinlock_irqsave)(&usb9pfs->lock);
ret = usb9pfs_queue_tx(usb9pfs, p9_req, GFP_ATOMIC);
if (ret)
return ret;
list_del(&p9_req->req_list);
p9_req_get(p9_req);
return ret;
}
static void usb9pfs_tx_complete(struct usb_ep *ep, struct usb_request *req)
{
struct f_usb9pfs *usb9pfs = ep->driver_data;
struct usb_composite_dev *cdev = usb9pfs->function.config->cdev;
struct p9_req_t *p9_tx_req = req->context;
unsigned long flags;
/* reset zero packages */
req->zero = 0;
if (req->status) {
dev_err(&cdev->gadget->dev, "%s usb9pfs complete --> %d, %d/%d\n",
ep->name, req->status, req->actual, req->length);
return;
}
dev_dbg(&cdev->gadget->dev, "%s usb9pfs complete --> %d, %d/%d\n",
ep->name, req->status, req->actual, req->length);
spin_lock_irqsave(&usb9pfs->lock, flags);
WRITE_ONCE(p9_tx_req->status, REQ_STATUS_SENT);
p9_req_put(usb9pfs->client, p9_tx_req);
req->context = NULL;
spin_unlock_irqrestore(&usb9pfs->lock, flags);
complete(&usb9pfs->send);
}
static struct p9_req_t *usb9pfs_rx_header(struct f_usb9pfs *usb9pfs, void *buf)
{
struct p9_req_t *p9_rx_req;
struct p9_fcall rc;
int ret;
/* start by reading header */
rc.sdata = buf;
rc.offset = 0;
rc.capacity = P9_HDRSZ;
rc.size = P9_HDRSZ;
p9_debug(P9_DEBUG_TRANS, "mux %p got %zu bytes\n", usb9pfs,
rc.capacity - rc.offset);
ret = p9_parse_header(&rc, &rc.size, NULL, NULL, 0);
if (ret) {
p9_debug(P9_DEBUG_ERROR,
"error parsing header: %d\n", ret);
return NULL;
}
p9_debug(P9_DEBUG_TRANS,
"mux %p pkt: size: %d bytes tag: %d\n",
usb9pfs, rc.size, rc.tag);
p9_rx_req = p9_tag_lookup(usb9pfs->client, rc.tag);
if (!p9_rx_req || p9_rx_req->status != REQ_STATUS_SENT) {
p9_debug(P9_DEBUG_ERROR, "Unexpected packet tag %d\n", rc.tag);
return NULL;
}
if (rc.size > p9_rx_req->rc.capacity) {
p9_debug(P9_DEBUG_ERROR,
"requested packet size too big: %d for tag %d with capacity %zd\n",
rc.size, rc.tag, p9_rx_req->rc.capacity);
p9_req_put(usb9pfs->client, p9_rx_req);
return NULL;
}
if (!p9_rx_req->rc.sdata) {
p9_debug(P9_DEBUG_ERROR,
"No recv fcall for tag %d (req %p), disconnecting!\n",
rc.tag, p9_rx_req);
p9_req_put(usb9pfs->client, p9_rx_req);
return NULL;
}
return p9_rx_req;
}
static void usb9pfs_rx_complete(struct usb_ep *ep, struct usb_request *req)
{
struct f_usb9pfs *usb9pfs = ep->driver_data;
struct usb_composite_dev *cdev = usb9pfs->function.config->cdev;
struct p9_req_t *p9_rx_req;
if (req->status) {
dev_err(&cdev->gadget->dev, "%s usb9pfs complete --> %d, %d/%d\n",
ep->name, req->status, req->actual, req->length);
return;
}
p9_rx_req = usb9pfs_rx_header(usb9pfs, req->buf);
if (!p9_rx_req)
return;
memcpy(p9_rx_req->rc.sdata, req->buf, req->actual);
p9_rx_req->rc.size = req->actual;
p9_client_cb(usb9pfs->client, p9_rx_req, REQ_STATUS_RCVD);
p9_req_put(usb9pfs->client, p9_rx_req);
complete(&usb9pfs->received);
}
static void disable_ep(struct usb_composite_dev *cdev, struct usb_ep *ep)
{
int value;
value = usb_ep_disable(ep);
if (value < 0)
dev_info(&cdev->gadget->dev,
"disable %s --> %d\n", ep->name, value);
}
static void disable_usb9pfs(struct f_usb9pfs *usb9pfs)
{
struct usb_composite_dev *cdev =
usb9pfs->function.config->cdev;
if (usb9pfs->in_req) {
usb_ep_free_request(usb9pfs->in_ep, usb9pfs->in_req);
usb9pfs->in_req = NULL;
}
if (usb9pfs->out_req) {
usb_ep_free_request(usb9pfs->out_ep, usb9pfs->out_req);
usb9pfs->out_req = NULL;
}
disable_ep(cdev, usb9pfs->in_ep);
disable_ep(cdev, usb9pfs->out_ep);
dev_dbg(&cdev->gadget->dev, "%s disabled\n",
usb9pfs->function.name);
}
static int alloc_requests(struct usb_composite_dev *cdev,
struct f_usb9pfs *usb9pfs)
{
int ret;
usb9pfs->in_req = usb_ep_alloc_request(usb9pfs->in_ep, GFP_ATOMIC);
if (!usb9pfs->in_req) {
ret = -ENOENT;
goto fail;
}
usb9pfs->out_req = alloc_ep_req(usb9pfs->out_ep, usb9pfs->buflen);
if (!usb9pfs->out_req) {
ret = -ENOENT;
goto fail_in;
}
usb9pfs->in_req->complete = usb9pfs_tx_complete;
usb9pfs->out_req->complete = usb9pfs_rx_complete;
/* length will be set in complete routine */
usb9pfs->in_req->context = usb9pfs;
usb9pfs->out_req->context = usb9pfs;
return 0;
fail_in:
usb_ep_free_request(usb9pfs->in_ep, usb9pfs->in_req);
fail:
return ret;
}
static int enable_endpoint(struct usb_composite_dev *cdev,
struct f_usb9pfs *usb9pfs, struct usb_ep *ep)
{
int ret;
ret = config_ep_by_speed(cdev->gadget, &usb9pfs->function, ep);
if (ret)
return ret;
ret = usb_ep_enable(ep);
if (ret < 0)
return ret;
ep->driver_data = usb9pfs;
return 0;
}
static int
enable_usb9pfs(struct usb_composite_dev *cdev, struct f_usb9pfs *usb9pfs)
{
struct p9_client *client;
int ret = 0;
ret = enable_endpoint(cdev, usb9pfs, usb9pfs->in_ep);
if (ret)
goto out;
ret = enable_endpoint(cdev, usb9pfs, usb9pfs->out_ep);
if (ret)
goto disable_in;
ret = alloc_requests(cdev, usb9pfs);
if (ret)
goto disable_out;
client = usb9pfs->client;
if (client)
client->status = Connected;
dev_dbg(&cdev->gadget->dev, "%s enabled\n", usb9pfs->function.name);
return 0;
disable_out:
usb_ep_disable(usb9pfs->out_ep);
disable_in:
usb_ep_disable(usb9pfs->in_ep);
out:
return ret;
}
static int p9_usbg_create(struct p9_client *client, const char *devname, char *args)
{
struct f_usb9pfs_dev *dev;
struct f_usb9pfs *usb9pfs;
int ret = -ENOENT;
int found = 0;
if (!devname)
return -EINVAL;
guard(mutex)(&usb9pfs_lock);
list_for_each_entry(dev, &usbg_instance_list, usb9pfs_instance) {
if (!strncmp(devname, dev->tag, strlen(devname))) {
if (!dev->inuse) {
dev->inuse = true;
found = 1;
break;
}
ret = -EBUSY;
break;
}
}
if (!found) {
pr_err("no channels available for device %s\n", devname);
return ret;
}
usb9pfs = dev->usb9pfs;
if (!usb9pfs)
return -EINVAL;
client->trans = (void *)usb9pfs;
if (!usb9pfs->in_req)
client->status = Disconnected;
else
client->status = Connected;
usb9pfs->client = client;
client->trans_mod->maxsize = usb9pfs->buflen;
complete(&usb9pfs->received);
return 0;
}
static void usb9pfs_clear_tx(struct f_usb9pfs *usb9pfs)
{
struct p9_req_t *req;
guard(spinlock_irqsave)(&usb9pfs->lock);
req = usb9pfs->in_req->context;
if (!req)
return;
if (!req->t_err)
req->t_err = -ECONNRESET;
p9_client_cb(usb9pfs->client, req, REQ_STATUS_ERROR);
}
static void p9_usbg_close(struct p9_client *client)
{
struct f_usb9pfs *usb9pfs;
struct f_usb9pfs_dev *dev;
struct f_usb9pfs_opts *opts;
if (!client)
return;
usb9pfs = client->trans;
if (!usb9pfs)
return;
client->status = Disconnected;
usb9pfs_clear_tx(usb9pfs);
opts = container_of(usb9pfs->function.fi,
struct f_usb9pfs_opts, func_inst);
dev = opts->dev;
mutex_lock(&usb9pfs_lock);
dev->inuse = false;
mutex_unlock(&usb9pfs_lock);
}
static int p9_usbg_request(struct p9_client *client, struct p9_req_t *p9_req)
{
struct f_usb9pfs *usb9pfs = client->trans;
int ret;
if (client->status != Connected)
return -EBUSY;
ret = wait_for_completion_killable(&usb9pfs->received);
if (ret)
return ret;
ret = usb9pfs_transmit(usb9pfs, p9_req);
if (ret)
return ret;
ret = wait_for_completion_killable(&usb9pfs->send);
if (ret)
return ret;
return usb9pfs_queue_rx(usb9pfs, usb9pfs->out_req, GFP_ATOMIC);
}
static int p9_usbg_cancel(struct p9_client *client, struct p9_req_t *req)
{
struct f_usb9pfs *usb9pfs = client->trans;
int ret = 1;
p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req);
guard(spinlock_irqsave)(&usb9pfs->lock);
if (req->status == REQ_STATUS_UNSENT) {
list_del(&req->req_list);
WRITE_ONCE(req->status, REQ_STATUS_FLSHD);
p9_req_put(client, req);
ret = 0;
}
return ret;
}
static struct p9_trans_module p9_usbg_trans = {
.name = "usbg",
.create = p9_usbg_create,
.close = p9_usbg_close,
.request = p9_usbg_request,
.cancel = p9_usbg_cancel,
.owner = THIS_MODULE,
};
/*-------------------------------------------------------------------------*/
#define USB_PROTOCOL_9PFS 0x09
static struct usb_interface_descriptor usb9pfs_intf = {
.bLength = sizeof(usb9pfs_intf),
.bDescriptorType = USB_DT_INTERFACE,
.bNumEndpoints = 2,
.bInterfaceClass = USB_CLASS_VENDOR_SPEC,
.bInterfaceSubClass = USB_SUBCLASS_VENDOR_SPEC,
.bInterfaceProtocol = USB_PROTOCOL_9PFS,
/* .iInterface = DYNAMIC */
};
/* full speed support: */
static struct usb_endpoint_descriptor fs_usb9pfs_source_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
};
static struct usb_endpoint_descriptor fs_usb9pfs_sink_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_OUT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
};
static struct usb_descriptor_header *fs_usb9pfs_descs[] = {
(struct usb_descriptor_header *)&usb9pfs_intf,
(struct usb_descriptor_header *)&fs_usb9pfs_sink_desc,
(struct usb_descriptor_header *)&fs_usb9pfs_source_desc,
NULL,
};
/* high speed support: */
static struct usb_endpoint_descriptor hs_usb9pfs_source_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(512),
};
static struct usb_endpoint_descriptor hs_usb9pfs_sink_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(512),
};
static struct usb_descriptor_header *hs_usb9pfs_descs[] = {
(struct usb_descriptor_header *)&usb9pfs_intf,
(struct usb_descriptor_header *)&hs_usb9pfs_source_desc,
(struct usb_descriptor_header *)&hs_usb9pfs_sink_desc,
NULL,
};
/* super speed support: */
static struct usb_endpoint_descriptor ss_usb9pfs_source_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(1024),
};
static struct usb_ss_ep_comp_descriptor ss_usb9pfs_source_comp_desc = {
.bLength = USB_DT_SS_EP_COMP_SIZE,
.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
.bMaxBurst = 0,
.bmAttributes = 0,
.wBytesPerInterval = 0,
};
static struct usb_endpoint_descriptor ss_usb9pfs_sink_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(1024),
};
static struct usb_ss_ep_comp_descriptor ss_usb9pfs_sink_comp_desc = {
.bLength = USB_DT_SS_EP_COMP_SIZE,
.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
.bMaxBurst = 0,
.bmAttributes = 0,
.wBytesPerInterval = 0,
};
static struct usb_descriptor_header *ss_usb9pfs_descs[] = {
(struct usb_descriptor_header *)&usb9pfs_intf,
(struct usb_descriptor_header *)&ss_usb9pfs_source_desc,
(struct usb_descriptor_header *)&ss_usb9pfs_source_comp_desc,
(struct usb_descriptor_header *)&ss_usb9pfs_sink_desc,
(struct usb_descriptor_header *)&ss_usb9pfs_sink_comp_desc,
NULL,
};
/* function-specific strings: */
static struct usb_string strings_usb9pfs[] = {
[0].s = "usb9pfs input to output",
{ } /* end of list */
};
static struct usb_gadget_strings stringtab_usb9pfs = {
.language = 0x0409, /* en-us */
.strings = strings_usb9pfs,
};
static struct usb_gadget_strings *usb9pfs_strings[] = {
&stringtab_usb9pfs,
NULL,
};
/*-------------------------------------------------------------------------*/
static int usb9pfs_func_bind(struct usb_configuration *c,
struct usb_function *f)
{
struct f_usb9pfs *usb9pfs = func_to_usb9pfs(f);
struct f_usb9pfs_opts *opts;
struct usb_composite_dev *cdev = c->cdev;
int ret;
int id;
/* allocate interface ID(s) */
id = usb_interface_id(c, f);
if (id < 0)
return id;
usb9pfs_intf.bInterfaceNumber = id;
id = usb_string_id(cdev);
if (id < 0)
return id;
strings_usb9pfs[0].id = id;
usb9pfs_intf.iInterface = id;
/* allocate endpoints */
usb9pfs->in_ep = usb_ep_autoconfig(cdev->gadget,
&fs_usb9pfs_source_desc);
if (!usb9pfs->in_ep)
goto autoconf_fail;
usb9pfs->out_ep = usb_ep_autoconfig(cdev->gadget,
&fs_usb9pfs_sink_desc);
if (!usb9pfs->out_ep)
goto autoconf_fail;
/* support high speed hardware */
hs_usb9pfs_source_desc.bEndpointAddress =
fs_usb9pfs_source_desc.bEndpointAddress;
hs_usb9pfs_sink_desc.bEndpointAddress =
fs_usb9pfs_sink_desc.bEndpointAddress;
/* support super speed hardware */
ss_usb9pfs_source_desc.bEndpointAddress =
fs_usb9pfs_source_desc.bEndpointAddress;
ss_usb9pfs_sink_desc.bEndpointAddress =
fs_usb9pfs_sink_desc.bEndpointAddress;
ret = usb_assign_descriptors(f, fs_usb9pfs_descs, hs_usb9pfs_descs,
ss_usb9pfs_descs, ss_usb9pfs_descs);
if (ret)
return ret;
opts = container_of(f->fi, struct f_usb9pfs_opts, func_inst);
opts->dev->usb9pfs = usb9pfs;
dev_dbg(&cdev->gadget->dev, "%s speed %s: IN/%s, OUT/%s\n",
(gadget_is_superspeed(c->cdev->gadget) ? "super" :
(gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full")),
f->name, usb9pfs->in_ep->name, usb9pfs->out_ep->name);
return 0;
autoconf_fail:
ERROR(cdev, "%s: can't autoconfigure on %s\n",
f->name, cdev->gadget->name);
return -ENODEV;
}
static void usb9pfs_func_unbind(struct usb_configuration *c,
struct usb_function *f)
{
struct f_usb9pfs *usb9pfs = func_to_usb9pfs(f);
disable_usb9pfs(usb9pfs);
}
static void usb9pfs_free_func(struct usb_function *f)
{
struct f_usb9pfs *usb9pfs = func_to_usb9pfs(f);
struct f_usb9pfs_opts *opts;
kfree(usb9pfs);
opts = container_of(f->fi, struct f_usb9pfs_opts, func_inst);
mutex_lock(&opts->lock);
opts->refcnt--;
mutex_unlock(&opts->lock);
usb_free_all_descriptors(f);
}
static int usb9pfs_set_alt(struct usb_function *f,
unsigned int intf, unsigned int alt)
{
struct f_usb9pfs *usb9pfs = func_to_usb9pfs(f);
struct usb_composite_dev *cdev = f->config->cdev;
return enable_usb9pfs(cdev, usb9pfs);
}
static void usb9pfs_disable(struct usb_function *f)
{
struct f_usb9pfs *usb9pfs = func_to_usb9pfs(f);
usb9pfs_clear_tx(usb9pfs);
}
static struct usb_function *usb9pfs_alloc(struct usb_function_instance *fi)
{
struct f_usb9pfs_opts *usb9pfs_opts;
struct f_usb9pfs *usb9pfs;
usb9pfs = kzalloc(sizeof(*usb9pfs), GFP_KERNEL);
if (!usb9pfs)
return ERR_PTR(-ENOMEM);
spin_lock_init(&usb9pfs->lock);
init_completion(&usb9pfs->send);
init_completion(&usb9pfs->received);
usb9pfs_opts = container_of(fi, struct f_usb9pfs_opts, func_inst);
mutex_lock(&usb9pfs_opts->lock);
usb9pfs_opts->refcnt++;
mutex_unlock(&usb9pfs_opts->lock);
usb9pfs->buflen = usb9pfs_opts->buflen;
usb9pfs->function.name = "usb9pfs";
usb9pfs->function.bind = usb9pfs_func_bind;
usb9pfs->function.unbind = usb9pfs_func_unbind;
usb9pfs->function.set_alt = usb9pfs_set_alt;
usb9pfs->function.disable = usb9pfs_disable;
usb9pfs->function.strings = usb9pfs_strings;
usb9pfs->function.free_func = usb9pfs_free_func;
return &usb9pfs->function;
}
static inline struct f_usb9pfs_opts *to_f_usb9pfs_opts(struct config_item *item)
{
return container_of(to_config_group(item), struct f_usb9pfs_opts,
func_inst.group);
}
static inline struct f_usb9pfs_opts *fi_to_f_usb9pfs_opts(struct usb_function_instance *fi)
{
return container_of(fi, struct f_usb9pfs_opts, func_inst);
}
static void usb9pfs_attr_release(struct config_item *item)
{
struct f_usb9pfs_opts *usb9pfs_opts = to_f_usb9pfs_opts(item);
usb_put_function_instance(&usb9pfs_opts->func_inst);
}
static struct configfs_item_operations usb9pfs_item_ops = {
.release = usb9pfs_attr_release,
};
static ssize_t f_usb9pfs_opts_buflen_show(struct config_item *item, char *page)
{
struct f_usb9pfs_opts *opts = to_f_usb9pfs_opts(item);
int ret;
mutex_lock(&opts->lock);
ret = sysfs_emit(page, "%d\n", opts->buflen);
mutex_unlock(&opts->lock);
return ret;
}
static ssize_t f_usb9pfs_opts_buflen_store(struct config_item *item,
const char *page, size_t len)
{
struct f_usb9pfs_opts *opts = to_f_usb9pfs_opts(item);
int ret;
u32 num;
guard(mutex)(&opts->lock);
if (opts->refcnt)
return -EBUSY;
ret = kstrtou32(page, 0, &num);
if (ret)
return ret;
opts->buflen = num;
return len;
}
CONFIGFS_ATTR(f_usb9pfs_opts_, buflen);
static struct configfs_attribute *usb9pfs_attrs[] = {
&f_usb9pfs_opts_attr_buflen,
NULL,
};
static const struct config_item_type usb9pfs_func_type = {
.ct_item_ops = &usb9pfs_item_ops,
.ct_attrs = usb9pfs_attrs,
.ct_owner = THIS_MODULE,
};
static struct f_usb9pfs_dev *_usb9pfs_do_find_dev(const char *tag)
{
struct f_usb9pfs_dev *usb9pfs_dev;
if (!tag)
return NULL;
list_for_each_entry(usb9pfs_dev, &usbg_instance_list, usb9pfs_instance) {
if (strcmp(usb9pfs_dev->tag, tag) == 0)
return usb9pfs_dev;
}
return NULL;
}
static int usb9pfs_tag_instance(struct f_usb9pfs_dev *dev, const char *tag)
{
struct f_usb9pfs_dev *existing;
int ret = 0;
guard(mutex)(&usb9pfs_lock);
existing = _usb9pfs_do_find_dev(tag);
if (!existing)
strscpy(dev->tag, tag, ARRAY_SIZE(dev->tag));
else if (existing != dev)
ret = -EBUSY;
return ret;
}
static int usb9pfs_set_inst_tag(struct usb_function_instance *fi, const char *tag)
{
if (strlen(tag) >= sizeof_field(struct f_usb9pfs_dev, tag))
return -ENAMETOOLONG;
return usb9pfs_tag_instance(fi_to_f_usb9pfs_opts(fi)->dev, tag);
}
static void usb9pfs_free_instance(struct usb_function_instance *fi)
{
struct f_usb9pfs_opts *usb9pfs_opts =
container_of(fi, struct f_usb9pfs_opts, func_inst);
struct f_usb9pfs_dev *dev = usb9pfs_opts->dev;
mutex_lock(&usb9pfs_lock);
list_del(&dev->usb9pfs_instance);
mutex_unlock(&usb9pfs_lock);
kfree(usb9pfs_opts);
}
static struct usb_function_instance *usb9pfs_alloc_instance(void)
{
struct f_usb9pfs_opts *usb9pfs_opts;
struct f_usb9pfs_dev *dev;
usb9pfs_opts = kzalloc(sizeof(*usb9pfs_opts), GFP_KERNEL);
if (!usb9pfs_opts)
return ERR_PTR(-ENOMEM);
mutex_init(&usb9pfs_opts->lock);
usb9pfs_opts->func_inst.set_inst_name = usb9pfs_set_inst_tag;
usb9pfs_opts->func_inst.free_func_inst = usb9pfs_free_instance;
usb9pfs_opts->buflen = DEFAULT_BUFLEN;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (IS_ERR(dev)) {
kfree(usb9pfs_opts);
return ERR_CAST(dev);
}
usb9pfs_opts->dev = dev;
dev->opts = usb9pfs_opts;
config_group_init_type_name(&usb9pfs_opts->func_inst.group, "",
&usb9pfs_func_type);
mutex_lock(&usb9pfs_lock);
list_add_tail(&dev->usb9pfs_instance, &usbg_instance_list);
mutex_unlock(&usb9pfs_lock);
return &usb9pfs_opts->func_inst;
}
DECLARE_USB_FUNCTION(usb9pfs, usb9pfs_alloc_instance, usb9pfs_alloc);
static int __init usb9pfs_modinit(void)
{
int ret;
INIT_LIST_HEAD(&usbg_instance_list);
ret = usb_function_register(&usb9pfsusb_func);
if (!ret)
v9fs_register_trans(&p9_usbg_trans);
return ret;
}
static void __exit usb9pfs_modexit(void)
{
usb_function_unregister(&usb9pfsusb_func);
v9fs_unregister_trans(&p9_usbg_trans);
}
module_init(usb9pfs_modinit);
module_exit(usb9pfs_modexit);
MODULE_ALIAS_9P("usbg");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("USB gadget 9pfs transport");
MODULE_AUTHOR("Michael Grzeschik");
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