usb: gadget: f_fs: virtual endpoint address mapping

This patch introduces virtual endpoint address mapping. It separates
function logic form physical endpoint addresses making it more hardware
independent.

Following modifications changes user space API, so to enable them user
have to switch on the FUNCTIONFS_VIRTUAL_ADDR flag in descriptors.

Endpoints are now refered using virtual endpoint addresses chosen by
user in endpoint descpriptors. This applies to each context when endpoint
address can be used:
- when accessing endpoint files in FunctionFS filesystemi (in file name),
- in setup requests directed to specific endpoint (in wIndex field),
- in descriptors returned by FUNCTIONFS_ENDPOINT_DESC ioctl.

In endpoint file names the endpoint address number is formatted as
double-digit hexadecimal value ("ep%02x") which has few advantages -
it is easy to parse, allows to easly recognize endpoint direction basing
on its name (IN endpoint number starts with digit 8, and OUT with 0)
which can be useful for debugging purpose, and it makes easier to introduce
further features allowing to use each endpoint number in both directions
to have more endpoints available for function if hardware supports this
(for example we could have ep01 which is endpoint 1 with OUT direction,
and ep81 which is endpoint 1 with IN direction).

Physical endpoint address can be still obtained using ioctl named
FUNCTIONFS_ENDPOINT_REVMAP, but now it's not neccesary to handle
USB transactions properly.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index e4afe8df555345e457e11dd80ea91e10603f34af..4ad11e03cf540d69be8427e4e0547edcf83a4207 100644 (file)
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1557,7 +1557,10 @@ static int ffs_epfiles_create(struct ffs_data *ffs)
                epfile->ffs = ffs;
                mutex_init(&epfile->mutex);
                init_waitqueue_head(&epfile->wait);
-               sprintf(epfiles->name, "ep%u",  i);
+               if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
+                       sprintf(epfiles->name, "ep%02x", ffs->eps_addrmap[i]);
+               else
+                       sprintf(epfiles->name, "ep%u", i);
                if (!unlikely(ffs_sb_create_file(ffs->sb, epfiles->name, epfile,
                                                 &ffs_epfile_operations,
                                                 &epfile->dentry))) {
@@ -2106,10 +2109,12 @@ static int __ffs_data_got_descs(struct ffs_data *ffs,
                break;
        case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
                flags = get_unaligned_le32(data + 8);
+               ffs->user_flags = flags;
                if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
                              FUNCTIONFS_HAS_HS_DESC |
                              FUNCTIONFS_HAS_SS_DESC |
-                             FUNCTIONFS_HAS_MS_OS_DESC)) {
+                             FUNCTIONFS_HAS_MS_OS_DESC |
+                             FUNCTIONFS_VIRTUAL_ADDR)) {
                        ret = -ENOSYS;
                        goto error;
                }
@@ -2466,7 +2471,13 @@ static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
        } else {
                struct usb_request *req;
                struct usb_ep *ep;
+               u8 bEndpointAddress;
 
+               /*
+                * We back up bEndpointAddress because autoconfig overwrites
+                * it with physical endpoint address.
+                */
+               bEndpointAddress = ds->bEndpointAddress;
                pr_vdebug("autoconfig\n");
                ep = usb_ep_autoconfig(func->gadget, ds);
                if (unlikely(!ep))
@@ -2481,6 +2492,12 @@ static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
                ffs_ep->req = req;
                func->eps_revmap[ds->bEndpointAddress &
                                 USB_ENDPOINT_NUMBER_MASK] = idx + 1;
+               /*
+                * If we use virtual address mapping, we restore
+                * original bEndpointAddress value.
+                */
+               if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
+                       ds->bEndpointAddress = bEndpointAddress;
        }
        ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
 
@@ -2925,6 +2942,8 @@ static int ffs_func_setup(struct usb_function *f,
                ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
                if (unlikely(ret < 0))
                        return ret;
+               if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
+                       ret = func->ffs->eps_addrmap[ret];
                break;
 
        default:

diff --git a/drivers/usb/gadget/function/u_fs.h b/drivers/usb/gadget/function/u_fs.h
index d48897e8ffebf03db2f39ec77ba695364b4174a2..cd128e31f808b91fb29c292cabbe6affdb5d8116 100644 (file)
--- a/drivers/usb/gadget/function/u_fs.h
+++ b/drivers/usb/gadget/function/u_fs.h
@@ -224,6 +224,8 @@ struct ffs_data {
        void                            *ms_os_descs_ext_prop_name_avail;
        void                            *ms_os_descs_ext_prop_data_avail;
 
+       unsigned                        user_flags;
+
        u8                              eps_addrmap[15];
 
        unsigned short                  strings_count;

diff --git a/include/uapi/linux/usb/functionfs.h b/include/uapi/linux/usb/functionfs.h
index 7c7a2feb0e6e7770457bd69452c9bb9deca20850..295ba299e7bdb6b57f59b2f642fe43cae348e86a 100644 (file)
--- a/include/uapi/linux/usb/functionfs.h
+++ b/include/uapi/linux/usb/functionfs.h
@@ -19,6 +19,7 @@ enum functionfs_flags {
        FUNCTIONFS_HAS_HS_DESC = 2,
        FUNCTIONFS_HAS_SS_DESC = 4,
        FUNCTIONFS_HAS_MS_OS_DESC = 8,
+       FUNCTIONFS_VIRTUAL_ADDR = 16,
 };
 
 /* Descriptor of an non-audio endpoint */