Make the midi function available for gadgets composed with configfs.
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxx>
---
Documentation/ABI/testing/configfs-usb-gadget-midi | 12 ++
drivers/usb/gadget/Kconfig | 14 ++
drivers/usb/gadget/function/f_midi.c | 161 ++++++++++++++++++++-
drivers/usb/gadget/function/u_midi.h | 8 +
4 files changed, 193 insertions(+), 2 deletions(-)
create mode 100644 Documentation/ABI/testing/configfs-usb-gadget-midi
diff --git a/Documentation/ABI/testing/configfs-usb-gadget-midi b/Documentation/ABI/testing/configfs-usb-gadget-midi
new file mode 100644
index 0000000..6b341df
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-usb-gadget-midi
@@ -0,0 +1,12 @@
+What: /config/usb-gadget/gadget/functions/midi.name
+Date: Nov 2014
+KernelVersion: 3.19
+Description:
+ The attributes:
+
+ index - index value for the USB MIDI adapter
+ id - ID string for the USB MIDI adapter
+ buflen - MIDI buffer length
+ qlen - USB read request queue length
+ in_ports - number of MIDI input ports
+ out_ports - number of MIDI output ports
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 9815237..9004fcc 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -365,6 +365,20 @@ config USB_CONFIGFS_F_FS
implemented in kernel space (for instance Ethernet, serial or
mass storage) and other are implemented in user space.
+config USB_CONFIGFS_F_MIDI
+ boolean "MIDI function"
+ depends on USB_CONFIGFS
+ depends on SND
+ select USB_LIBCOMPOSITE
+ select SND_RAWMIDI
+ select USB_F_MIDI
+ help
+ The MIDI Function acts as a USB Audio device, with one MIDI
+ input and one MIDI output. These MIDI jacks appear as
+ a sound "card" in the ALSA sound system. Other MIDI
+ connections can then be made on the gadget system, using
+ ALSA's aconnect utility etc.
+
source "drivers/usb/gadget/legacy/Kconfig"
endchoice
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index ec2a9ce..1f94dad 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -896,12 +896,145 @@ fail_register:
return status;
}
+static inline struct f_midi_opts *to_f_midi_opts(struct config_item *item)
+{
+ return container_of(to_config_group(item), struct f_midi_opts,
+ func_inst.group);
+}
+
+CONFIGFS_ATTR_STRUCT(f_midi_opts);
+CONFIGFS_ATTR_OPS(f_midi_opts);
+
+static void midi_attr_release(struct config_item *item)
+{
+ struct f_midi_opts *opts = to_f_midi_opts(item);
+
+ usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations midi_item_ops = {
+ .release = midi_attr_release,
+ .show_attribute = f_midi_opts_attr_show,
+ .store_attribute = f_midi_opts_attr_store,
+};
+
+#define F_MIDI_OPT(name, test_limit, limit) \
+static ssize_t f_midi_opts_##name##_show(struct f_midi_opts *opts, char *page) \
+{ \
+ int result; \
+ \
+ mutex_lock(&opts->lock); \
+ result = sprintf(page, "%d\n", opts->name); \
+ mutex_unlock(&opts->lock); \
+ \
+ return result; \
+} \
+ \
+static ssize_t f_midi_opts_##name##_store(struct f_midi_opts *opts, \
+ const char *page, size_t len) \
+{ \
+ int ret; \
+ u32 num; \
+ \
+ mutex_lock(&opts->lock); \
+ if (opts->refcnt) { \
+ ret = -EBUSY; \
+ goto end; \
+ } \
+ \
+ ret = kstrtou32(page, 0, &num); \
+ if (ret) \
+ goto end; \
+ \
+ if (test_limit && num > limit) { \
+ ret = -EINVAL; \
+ goto end; \
+ } \
+ opts->name = num; \
+ ret = len; \
+ \
+end: \
+ mutex_unlock(&opts->lock); \
+ return ret; \
+} \
+ \
+static struct f_midi_opts_attribute f_midi_opts_##name = \
+ __CONFIGFS_ATTR(name, S_IRUGO | S_IWUSR, f_midi_opts_##name##_show, \
+ f_midi_opts_##name##_store)
+
+F_MIDI_OPT(index, true, SNDRV_CARDS);
+F_MIDI_OPT(buflen, false, 0);
+F_MIDI_OPT(qlen, false, 0);
+F_MIDI_OPT(in_ports, true, MAX_PORTS);
+F_MIDI_OPT(out_ports, true, MAX_PORTS);
+
+static ssize_t f_midi_opts_id_show(struct f_midi_opts *opts, char *page)
+{
+ int result;
+
+ mutex_lock(&opts->lock);
+ result = strlcpy(page, opts->id, PAGE_SIZE);
+ mutex_unlock(&opts->lock);
+
+ return result;
+}
+
+static ssize_t f_midi_opts_id_store(struct f_midi_opts *opts,
+ const char *page, size_t len)
+{
+ int ret;
+ char *c;
+
+ mutex_lock(&opts->lock);
+ if (opts->refcnt) {
+ ret = -EBUSY;
+ goto end;
+ }
+
+ c = kstrndup(page, len, GFP_KERNEL);
+ if (!c) {
+ ret = -ENOMEM;
+ goto end;
+ }
+ if (opts->id_allocated)
+ kfree(opts->id);
+ opts->id = c;
+ opts->id_allocated = true;
+ ret = len;
+end:
+ mutex_unlock(&opts->lock);
+ return ret;
+}
+
+static struct f_midi_opts_attribute f_midi_opts_id =
+ __CONFIGFS_ATTR(id, S_IRUGO | S_IWUSR, f_midi_opts_id_show,
+ f_midi_opts_id_store);
+
+static struct configfs_attribute *midi_attrs[] = {
+ &f_midi_opts_index.attr,
+ &f_midi_opts_buflen.attr,
+ &f_midi_opts_qlen.attr,
+ &f_midi_opts_in_ports.attr,
+ &f_midi_opts_out_ports.attr,
+ &f_midi_opts_id.attr,
+ NULL,
+};
+
+static struct config_item_type midi_func_type = {
+ .ct_item_ops = &midi_item_ops,
+ .ct_attrs = midi_attrs,
+ .ct_owner = THIS_MODULE,
+};
+
static void f_midi_free_inst(struct usb_function_instance *f)
{
struct f_midi_opts *opts;
opts = container_of(f, struct f_midi_opts, func_inst);
+ if (opts->id_allocated)
+ kfree(opts->id);
+
kfree(opts);
}
@@ -912,7 +1045,18 @@ static struct usb_function_instance *f_midi_alloc_inst(void)
opts = kzalloc(sizeof(*opts), GFP_KERNEL);
if (!opts)
return ERR_PTR(-ENOMEM);
+
+ mutex_init(&opts->lock);
opts->func_inst.free_func_inst = f_midi_free_inst;
+ opts->index = SNDRV_DEFAULT_IDX1;
+ opts->id = SNDRV_DEFAULT_STR1;
+ opts->buflen = 256;
+ opts->qlen = 32;
+ opts->in_ports = 1;
+ opts->out_ports = 1;
+
+ config_group_init_type_name(&opts->func_inst.group, "",
+ &midi_func_type);
return &opts->func_inst;
}
@@ -926,9 +1070,12 @@ static void f_midi_free(struct usb_function *f)
midi = func_to_midi(f);
opts = container_of(f->fi, struct f_midi_opts, func_inst);
kfree(midi->id);
+ mutex_lock(&opts->lock);
for (i = opts->in_ports - 1; i >= 0; --i)
kfree(midi->in_port[i]);
kfree(midi);
+ --opts->refcnt;
+ mutex_unlock(&opts->lock);
}
static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f)
@@ -957,20 +1104,27 @@ struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
int status, i;
opts = container_of(fi, struct f_midi_opts, func_inst);
+
+ mutex_lock(&opts->lock);
/* sanity check */
- if (opts->in_ports > MAX_PORTS || opts->out_ports > MAX_PORTS)
+ if (opts->in_ports > MAX_PORTS || opts->out_ports > MAX_PORTS) {
+ mutex_unlock(&opts->lock);
return ERR_PTR(-EINVAL);
+ }
/* allocate and initialize one new instance */
midi = kzalloc(sizeof(*midi), GFP_KERNEL);
- if (!midi)
+ if (!midi) {
+ mutex_unlock(&opts->lock);
return ERR_PTR(-ENOMEM);
+ }
for (i = 0; i < opts->in_ports; i++) {
struct gmidi_in_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
if (!port) {
status = -ENOMEM;
+ mutex_unlock(&opts->lock);
goto setup_fail;
}
@@ -984,6 +1138,7 @@ struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
midi->id = kstrdup(opts->id, GFP_KERNEL);
if (opts->id && !midi->id) {
status = -ENOMEM;
+ mutex_unlock(&opts->lock);
goto kstrdup_fail;
}
midi->in_ports = opts->in_ports;
@@ -991,6 +1146,8 @@ struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
midi->index = opts->index;
midi->buflen = opts->buflen;
midi->qlen = opts->qlen;
+ ++opts->refcnt;
+ mutex_unlock(&opts->lock);
midi->func.name = "gmidi function";
midi->func.bind = f_midi_bind;
diff --git a/drivers/usb/gadget/function/u_midi.h b/drivers/usb/gadget/function/u_midi.h
index 76bccc1..2251018 100644
--- a/drivers/usb/gadget/function/u_midi.h
+++ b/drivers/usb/gadget/function/u_midi.h
@@ -22,10 +22,18 @@ struct f_midi_opts {
struct usb_function_instance func_inst;
int index;
char *id;
+ bool id_allocated;
unsigned int in_ports;
unsigned int out_ports;
unsigned int buflen;
unsigned int qlen;
+
+ /*
+ * Protect the data form concurrent access by read/write
+ * and create symlink/remove symlink.
+ */
+ struct mutex lock;
+ int refcnt;
};
#endif /* U_MIDI_H */
--
1.9.1
--
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