[PATCH v3 0/9] Gadget endpoint request allocation and MIDI

[PATCH v3 0/9] Gadget endpoint request allocation and MIDI

[Felipe F. Tonello]

As discussed with Baolin Wang, Michal Nazarewicz and Felipe Balbi. I propose
the forced buffer alignment of OUT endpoints USB requests. This is implemented
by patches #1 and #2.

That not just simplifies the driver code, but it also prevents nasty bugs when
buflen is not aligned or even less than wMaxPacketSize.

Patch #9  removes direct calls to usb_ep_alloc_request() and use alloc_ep_req()
instead. If accepted, then we should apply to all other gadgets that uses
usb_ep_alloc_request() when possible and encorage drivers to use it instead.

Changes from v2:
 * Simplified logic in patch 1
 * Added documentation to alloc_ep_req and free_ep_req
 * Improved commit message on patch 7

Changes from v1:
 * Added patches 1, 2, 7, 8 ,9.
 * Patch 3 removes max_t() for buffer alignment with wMaxPacketSize

Felipe F. Tonello (9):
  usb: gadget: fix usb_ep_align_maybe endianness and new usb_ep_align
  usb: gadget: align buffer size when allocating for OUT endpoint
  usb: gadget: f_midi: remove alignment code for OUT endpoint
  usb: gadget: f_midi: defaults buflen sizes to 512
  usb: gadget: f_midi: refactor state machine
  usb: gadget: f_midi: drop substreams when disabling endpoint
  usb: gadget: remove useless parameter in alloc_ep_req()
  usb: gadget: f_hid: use free_ep_req()
  usb: gadget: f_hid: use alloc_ep_req()

 drivers/usb/gadget/function/f_hid.c        |  26 +---
 drivers/usb/gadget/function/f_loopback.c   |   9 +-
 drivers/usb/gadget/function/f_midi.c       | 240 +++++++++++++++++------------
 drivers/usb/gadget/function/f_sourcesink.c |  11 +-
 drivers/usb/gadget/legacy/gmidi.c          |   2 +-
 drivers/usb/gadget/u_f.c                   |   6 +-
 drivers/usb/gadget/u_f.h                   |  17 +-
 include/linux/usb/gadget.h                 |  17 +-
 8 files changed, 188 insertions(+), 140 deletions(-)

-- 
2.9.0

[PATCH v3 1/9] usb: gadget: fix usb_ep_align_maybe endianness and new usb_ep_align

[Felipe F. Tonello]

USB spec specifies wMaxPacketSize to be little endian (as other properties),
so when using this variable in the driver we should convert to the current
CPU endianness if necessary.

This patch also introduces usb_ep_align() which does always returns the
aligned buffer size for an endpoint. This is useful to be used by USB requests
allocator functions.

Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>
---
 include/linux/usb/gadget.h | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 612dbdfa388e..3cc93237ff98 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -418,8 +418,20 @@ static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
 	list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
 
 /**
+ * usb_ep_align - returns @len aligned to ep's maxpacketsize.
+ * @ep: the endpoint whose maxpacketsize is used to align @len
+ * @len: buffer size's length to align to @ep's maxpacketsize
+ *
+ * This helper is used to align buffer's size to an ep's maxpacketsize.
+ */
+static inline size_t usb_ep_align(struct usb_ep *ep, size_t len)
+{
+	return round_up(len, (size_t)le16_to_cpu(ep->desc->wMaxPacketSize));
+}
+
+/**
  * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
- *	requires quirk_ep_out_aligned_size, otherwise reguens len.
+ *	requires quirk_ep_out_aligned_size, otherwise returns len.
  * @g: controller to check for quirk
  * @ep: the endpoint whose maxpacketsize is used to align @len
  * @len: buffer size's length to align to @ep's maxpacketsize
@@ -430,8 +442,7 @@ static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
 static inline size_t
 usb_ep_align_maybe(struct usb_gadget *g, struct usb_ep *ep, size_t len)
 {
-	return !g->quirk_ep_out_aligned_size ? len :
-			round_up(len, (size_t)ep->desc->wMaxPacketSize);
+	return g->quirk_ep_out_aligned_size ? usb_ep_align(ep, len) : len;
 }
 
 /**
-- 
2.9.0

Re: [PATCH v3 1/9] usb: gadget: fix usb_ep_align_maybe endianness and new usb_ep_align

[Michal Nazarewicz]

On Fri, Aug 05 2016, Felipe F. Tonello wrote:
> USB spec specifies wMaxPacketSize to be little endian (as other properties),
> so when using this variable in the driver we should convert to the current
> CPU endianness if necessary.
>
> This patch also introduces usb_ep_align() which does always returns the
> aligned buffer size for an endpoint. This is useful to be used by USB requests
> allocator functions.
>
> Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>

Acked-by: Michal Nazarewicz <mina86@mina86.com>

> ---
>  include/linux/usb/gadget.h | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> index 612dbdfa388e..3cc93237ff98 100644
> --- a/include/linux/usb/gadget.h
> +++ b/include/linux/usb/gadget.h
> @@ -418,8 +418,20 @@ static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
>  	list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
>  
>  /**
> + * usb_ep_align - returns @len aligned to ep's maxpacketsize.
> + * @ep: the endpoint whose maxpacketsize is used to align @len
> + * @len: buffer size's length to align to @ep's maxpacketsize
> + *
> + * This helper is used to align buffer's size to an ep's maxpacketsize.
> + */
> +static inline size_t usb_ep_align(struct usb_ep *ep, size_t len)
> +{
> +	return round_up(len, (size_t)le16_to_cpu(ep->desc->wMaxPacketSize));
> +}
> +
> +/**
>   * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
> - *	requires quirk_ep_out_aligned_size, otherwise reguens len.
> + *	requires quirk_ep_out_aligned_size, otherwise returns len.
>   * @g: controller to check for quirk
>   * @ep: the endpoint whose maxpacketsize is used to align @len
>   * @len: buffer size's length to align to @ep's maxpacketsize
> @@ -430,8 +442,7 @@ static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
>  static inline size_t
>  usb_ep_align_maybe(struct usb_gadget *g, struct usb_ep *ep, size_t len)
>  {
> -	return !g->quirk_ep_out_aligned_size ? len :
> -			round_up(len, (size_t)ep->desc->wMaxPacketSize);
> +	return g->quirk_ep_out_aligned_size ? usb_ep_align(ep, len) : len;
>  }
>  
>  /**
> -- 
> 2.9.0
>

-- 
Best regards
ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ
«If at first you don’t succeed, give up skydiving»

[PATCH v3 2/9] usb: gadget: align buffer size when allocating for OUT endpoint

[Felipe F. Tonello]

Using usb_ep_align() makes sure that the buffer size for OUT endpoints is
always aligned with wMaxPacketSize (512 usually). This makes sure
that no buffer has the wrong size, which can cause nasty bugs.

Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>
---
 drivers/usb/gadget/u_f.c |  3 +++
 drivers/usb/gadget/u_f.h | 18 ++++++++++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/u_f.c b/drivers/usb/gadget/u_f.c
index 4bc7eea8bfc8..d1933b0b76c3 100644
--- a/drivers/usb/gadget/u_f.c
+++ b/drivers/usb/gadget/u_f.c
@@ -12,6 +12,7 @@
  */
 
 #include "u_f.h"
+#include <linux/usb/ch9.h>
 
 struct usb_request *alloc_ep_req(struct usb_ep *ep, int len, int default_len)
 {
@@ -20,6 +21,8 @@ struct usb_request *alloc_ep_req(struct usb_ep *ep, int len, int default_len)
 	req = usb_ep_alloc_request(ep, GFP_ATOMIC);
 	if (req) {
 		req->length = len ?: default_len;
+		if (usb_endpoint_dir_out(ep->desc))
+			req->length = usb_ep_align(ep, req->length);
 		req->buf = kmalloc(req->length, GFP_ATOMIC);
 		if (!req->buf) {
 			usb_ep_free_request(ep, req);
diff --git a/drivers/usb/gadget/u_f.h b/drivers/usb/gadget/u_f.h
index 4247cc098a89..69a1d10df04f 100644
--- a/drivers/usb/gadget/u_f.h
+++ b/drivers/usb/gadget/u_f.h
@@ -47,8 +47,22 @@
 struct usb_ep;
 struct usb_request;
 
-/* Requests allocated via alloc_ep_req() must be freed by free_ep_req(). */
-struct usb_request *alloc_ep_req(struct usb_ep *ep, int len, int default_len);
+/**
+ * alloc_ep_req - returns a usb_request allocated by the gadget driver and
+ * allocates the request's buffer.
+ *
+ * @ep: the endpoint to allocate a usb_request
+ * @len: usb_requests's buffer suggested size
+ * @default_len: used if @len is not provided, ie, is 0
+ *
+ * In case @ep direction is OUT, the @len will be aligned to ep's
+ * wMaxPacketSize. In order to avoid memory leaks or drops, *always* use
+ * usb_requests's length (req->length) to refer to the allocated buffer size.
+ * Requests allocated via alloc_ep_req() *must* be freed by free_ep_req().
+ */
+struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len, int default_len);
+
+/* Frees a usb_request previously allocated by alloc_ep_req() */
 static inline void free_ep_req(struct usb_ep *ep, struct usb_request *req)
 {
 	kfree(req->buf);
-- 
2.9.0

Re: [PATCH v3 2/9] usb: gadget: align buffer size when allocating for OUT endpoint

[kbuild test robot]

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Hi Felipe,

[auto build test ERROR on balbi-usb/next]
[also build test ERROR on v4.7 next-20160805]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Felipe-F-Tonello/Gadget-endpoint-request-allocation-and-MIDI/20160806-024520
base:   https://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb.git next
config: x86_64-randconfig-x013-201631 (attached as .config)
compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

Note: the linux-review/Felipe-F-Tonello/Gadget-endpoint-request-allocation-and-MIDI/20160806-024520 HEAD 5064a41cd5f89103e3b75c1a2ab9f6e98851503b builds fine.
      It only hurts bisectibility.

All errors (new ones prefixed by >>):

>> drivers/usb/gadget/u_f.c:17:21: error: conflicting types for 'alloc_ep_req'
    struct usb_request *alloc_ep_req(struct usb_ep *ep, int len, int default_len)
                        ^~~~~~~~~~~~
   In file included from drivers/usb/gadget/u_f.c:14:0:
   drivers/usb/gadget/u_f.h:63:21: note: previous declaration of 'alloc_ep_req' was here
    struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len, int default_len);
                        ^~~~~~~~~~~~

vim +/alloc_ep_req +17 drivers/usb/gadget/u_f.c

1efd54ea Andrzej Pietrasiewicz 2013-11-07  11   * published by the Free Software Foundation.
1efd54ea Andrzej Pietrasiewicz 2013-11-07  12   */
1efd54ea Andrzej Pietrasiewicz 2013-11-07  13  
1efd54ea Andrzej Pietrasiewicz 2013-11-07  14  #include "u_f.h"
a7ffc68f Felipe F. Tonello     2016-08-05  15  #include <linux/usb/ch9.h>
1efd54ea Andrzej Pietrasiewicz 2013-11-07  16  
1efd54ea Andrzej Pietrasiewicz 2013-11-07 @17  struct usb_request *alloc_ep_req(struct usb_ep *ep, int len, int default_len)
1efd54ea Andrzej Pietrasiewicz 2013-11-07  18  {
1efd54ea Andrzej Pietrasiewicz 2013-11-07  19  	struct usb_request      *req;
1efd54ea Andrzej Pietrasiewicz 2013-11-07  20  

:::::: The code at line 17 was first introduced by commit
:::::: 1efd54eab2b60c68c2ce75ea635306cef847d751 usb: gadget: factor out alloc_ep_req

:::::: TO: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
:::::: CC: Felipe Balbi <balbi@ti.com>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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Re: [PATCH v3 2/9] usb: gadget: align buffer size when allocating for OUT endpoint

[Felipe Ferreri Tonello]

[-- Attachment #1: Type: text/plain, Size: 2707 bytes --]

Hi,

On 05-08-2016 20:15, kbuild test robot wrote:
> Hi Felipe,
> 
> [auto build test ERROR on balbi-usb/next]
> [also build test ERROR on v4.7 next-20160805]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> 
> url:    https://github.com/0day-ci/linux/commits/Felipe-F-Tonello/Gadget-endpoint-request-allocation-and-MIDI/20160806-024520
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb.git next
> config: x86_64-randconfig-x013-201631 (attached as .config)
> compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
> reproduce:
>         # save the attached .config to linux build tree
>         make ARCH=x86_64 
> 
> Note: the linux-review/Felipe-F-Tonello/Gadget-endpoint-request-allocation-and-MIDI/20160806-024520 HEAD 5064a41cd5f89103e3b75c1a2ab9f6e98851503b builds fine.
>       It only hurts bisectibility.
> 
> All errors (new ones prefixed by >>):
> 
>>> drivers/usb/gadget/u_f.c:17:21: error: conflicting types for 'alloc_ep_req'
>     struct usb_request *alloc_ep_req(struct usb_ep *ep, int len, int default_len)
>                         ^~~~~~~~~~~~
>    In file included from drivers/usb/gadget/u_f.c:14:0:
>    drivers/usb/gadget/u_f.h:63:21: note: previous declaration of 'alloc_ep_req' was here
>     struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len, int default_len);

Ok, I made the mistake to change to size_t the len type just on the
function declaration. I'll fix this on a v4.

>                         ^~~~~~~~~~~~
> 
> vim +/alloc_ep_req +17 drivers/usb/gadget/u_f.c
> 
> 1efd54ea Andrzej Pietrasiewicz 2013-11-07  11   * published by the Free Software Foundation.
> 1efd54ea Andrzej Pietrasiewicz 2013-11-07  12   */
> 1efd54ea Andrzej Pietrasiewicz 2013-11-07  13  
> 1efd54ea Andrzej Pietrasiewicz 2013-11-07  14  #include "u_f.h"
> a7ffc68f Felipe F. Tonello     2016-08-05  15  #include <linux/usb/ch9.h>
> 1efd54ea Andrzej Pietrasiewicz 2013-11-07  16  
> 1efd54ea Andrzej Pietrasiewicz 2013-11-07 @17  struct usb_request *alloc_ep_req(struct usb_ep *ep, int len, int default_len)
> 1efd54ea Andrzej Pietrasiewicz 2013-11-07  18  {
> 1efd54ea Andrzej Pietrasiewicz 2013-11-07  19  	struct usb_request      *req;
> 1efd54ea Andrzej Pietrasiewicz 2013-11-07  20  
> 
> :::::: The code at line 17 was first introduced by commit
> :::::: 1efd54eab2b60c68c2ce75ea635306cef847d751 usb: gadget: factor out alloc_ep_req
> 
> :::::: TO: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
> :::::: CC: Felipe Balbi <balbi@ti.com>
> 
> ---
> 0-DAY kernel test infrastructure                Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
> 

Felipe

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[PATCH v3 3/9] usb: gadget: f_midi: remove alignment code for OUT endpoint

[Felipe F. Tonello]

The new version of alloc_ep_req() already aligns the buffer size to
wMaxPacketSize on OUT endpoints.

Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>
---
 drivers/usb/gadget/function/f_midi.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 58fc199a18ec..39018dea7035 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -360,9 +360,8 @@ static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 	/* allocate a bunch of read buffers and queue them all at once. */
 	for (i = 0; i < midi->qlen && err == 0; i++) {
 		struct usb_request *req =
-			midi_alloc_ep_req(midi->out_ep,
-				max_t(unsigned, midi->buflen,
-					bulk_out_desc.wMaxPacketSize));
+			midi_alloc_ep_req(midi->out_ep, midi->buflen);
+
 		if (req == NULL)
 			return -ENOMEM;
 
-- 
2.9.0

[PATCH v3 4/9] usb: gadget: f_midi: defaults buflen sizes to 512

[Felipe F. Tonello]

512 is the value used by wMaxPacketSize, as specified by the USB Spec. This
makes sure this driver uses, by default, the most optimal value for IN and OUT
endpoint requests.

Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>
---
 drivers/usb/gadget/function/f_midi.c | 2 +-
 drivers/usb/gadget/legacy/gmidi.c    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 39018dea7035..a7b50ac947f8 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -1122,7 +1122,7 @@ static struct usb_function_instance *f_midi_alloc_inst(void)
 	opts->func_inst.free_func_inst = f_midi_free_inst;
 	opts->index = SNDRV_DEFAULT_IDX1;
 	opts->id = SNDRV_DEFAULT_STR1;
-	opts->buflen = 256;
+	opts->buflen = 512;
 	opts->qlen = 32;
 	opts->in_ports = 1;
 	opts->out_ports = 1;
diff --git a/drivers/usb/gadget/legacy/gmidi.c b/drivers/usb/gadget/legacy/gmidi.c
index fc2ac150f5ff..0bf39c3ccdb1 100644
--- a/drivers/usb/gadget/legacy/gmidi.c
+++ b/drivers/usb/gadget/legacy/gmidi.c
@@ -47,7 +47,7 @@ static char *id = SNDRV_DEFAULT_STR1;
 module_param(id, charp, S_IRUGO);
 MODULE_PARM_DESC(id, "ID string for the USB MIDI Gadget adapter.");
 
-static unsigned int buflen = 256;
+static unsigned int buflen = 512;
 module_param(buflen, uint, S_IRUGO);
 MODULE_PARM_DESC(buflen, "MIDI buffer length");
 
-- 
2.9.0

Re: [PATCH v3 4/9] usb: gadget: f_midi: defaults buflen sizes to 512

[Michal Nazarewicz]

On Fri, Aug 05 2016, Felipe F. Tonello wrote:
> 512 is the value used by wMaxPacketSize, as specified by the USB Spec. This
> makes sure this driver uses, by default, the most optimal value for IN and OUT
> endpoint requests.
>
> Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>

Acked-by: Michal Nazarewicz <mina86@mina86.com>

> ---
>  drivers/usb/gadget/function/f_midi.c | 2 +-
>  drivers/usb/gadget/legacy/gmidi.c    | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
> index 39018dea7035..a7b50ac947f8 100644
> --- a/drivers/usb/gadget/function/f_midi.c
> +++ b/drivers/usb/gadget/function/f_midi.c
> @@ -1122,7 +1122,7 @@ static struct usb_function_instance *f_midi_alloc_inst(void)
>  	opts->func_inst.free_func_inst = f_midi_free_inst;
>  	opts->index = SNDRV_DEFAULT_IDX1;
>  	opts->id = SNDRV_DEFAULT_STR1;
> -	opts->buflen = 256;
> +	opts->buflen = 512;
>  	opts->qlen = 32;
>  	opts->in_ports = 1;
>  	opts->out_ports = 1;
> diff --git a/drivers/usb/gadget/legacy/gmidi.c b/drivers/usb/gadget/legacy/gmidi.c
> index fc2ac150f5ff..0bf39c3ccdb1 100644
> --- a/drivers/usb/gadget/legacy/gmidi.c
> +++ b/drivers/usb/gadget/legacy/gmidi.c
> @@ -47,7 +47,7 @@ static char *id = SNDRV_DEFAULT_STR1;
>  module_param(id, charp, S_IRUGO);
>  MODULE_PARM_DESC(id, "ID string for the USB MIDI Gadget adapter.");
>  
> -static unsigned int buflen = 256;
> +static unsigned int buflen = 512;
>  module_param(buflen, uint, S_IRUGO);
>  MODULE_PARM_DESC(buflen, "MIDI buffer length");
>  
> -- 
> 2.9.0
>

-- 
Best regards
ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ
«If at first you don’t succeed, give up skydiving»

[PATCH v3 5/9] usb: gadget: f_midi: refactor state machine

[Felipe F. Tonello]

This refactor results in a cleaner state machine code and promotes
consistency, readability, and maintanability of this driver.

This refactor state machine was well tested and it is currently running in
production code and devices.

Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>
---
 drivers/usb/gadget/function/f_midi.c | 204 ++++++++++++++++++++++-------------
 1 file changed, 129 insertions(+), 75 deletions(-)

diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index a7b50ac947f8..09d769e18b50 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -51,6 +51,19 @@ static const char f_midi_longname[] = "MIDI Gadget";
  */
 #define MAX_PORTS 16
 
+/* MIDI message states */
+enum {
+	STATE_INITIAL = 0,	/* pseudo state */
+	STATE_1PARAM,
+	STATE_2PARAM_1,
+	STATE_2PARAM_2,
+	STATE_SYSEX_0,
+	STATE_SYSEX_1,
+	STATE_SYSEX_2,
+	STATE_REAL_TIME,
+	STATE_FINISHED,		/* pseudo state */
+};
+
 /*
  * This is a gadget, and the IN/OUT naming is from the host's perspective.
  * USB -> OUT endpoint -> rawmidi
@@ -61,13 +74,6 @@ struct gmidi_in_port {
 	int active;
 	uint8_t cable;
 	uint8_t state;
-#define STATE_UNKNOWN	0
-#define STATE_1PARAM	1
-#define STATE_2PARAM_1	2
-#define STATE_2PARAM_2	3
-#define STATE_SYSEX_0	4
-#define STATE_SYSEX_1	5
-#define STATE_SYSEX_2	6
 	uint8_t data[2];
 };
 
@@ -403,118 +409,166 @@ static int f_midi_snd_free(struct snd_device *device)
 	return 0;
 }
 
-static void f_midi_transmit_packet(struct usb_request *req, uint8_t p0,
-					uint8_t p1, uint8_t p2, uint8_t p3)
-{
-	unsigned length = req->length;
-	u8 *buf = (u8 *)req->buf + length;
-
-	buf[0] = p0;
-	buf[1] = p1;
-	buf[2] = p2;
-	buf[3] = p3;
-	req->length = length + 4;
-}
-
 /*
  * Converts MIDI commands to USB MIDI packets.
  */
 static void f_midi_transmit_byte(struct usb_request *req,
 				 struct gmidi_in_port *port, uint8_t b)
 {
-	uint8_t p0 = port->cable << 4;
+	uint8_t p[4] = { port->cable << 4, 0, 0, 0 };
+	uint8_t next_state = STATE_INITIAL;
+
+	switch (b) {
+	case 0xf8 ... 0xff:
+		/* System Real-Time Messages */
+		p[0] |= 0x0f;
+		p[1] = b;
+		next_state = port->state;
+		port->state = STATE_REAL_TIME;
+		break;
+
+	case 0xf7:
+		/* End of SysEx */
+		switch (port->state) {
+		case STATE_SYSEX_0:
+			p[0] |= 0x05;
+			p[1] = 0xf7;
+			next_state = STATE_FINISHED;
+			break;
+		case STATE_SYSEX_1:
+			p[0] |= 0x06;
+			p[1] = port->data[0];
+			p[2] = 0xf7;
+			next_state = STATE_FINISHED;
+			break;
+		case STATE_SYSEX_2:
+			p[0] |= 0x07;
+			p[1] = port->data[0];
+			p[2] = port->data[1];
+			p[3] = 0xf7;
+			next_state = STATE_FINISHED;
+			break;
+		default:
+			/* Ignore byte */
+			next_state = port->state;
+			port->state = STATE_INITIAL;
+		}
+		break;
 
-	if (b >= 0xf8) {
-		f_midi_transmit_packet(req, p0 | 0x0f, b, 0, 0);
-	} else if (b >= 0xf0) {
+	case 0xf0 ... 0xf6:
+		/* System Common Messages */
+		port->data[0] = port->data[1] = 0;
+		port->state = STATE_INITIAL;
 		switch (b) {
 		case 0xf0:
 			port->data[0] = b;
-			port->state = STATE_SYSEX_1;
+			port->data[1] = 0;
+			next_state = STATE_SYSEX_1;
 			break;
 		case 0xf1:
 		case 0xf3:
 			port->data[0] = b;
-			port->state = STATE_1PARAM;
+			next_state = STATE_1PARAM;
 			break;
 		case 0xf2:
 			port->data[0] = b;
-			port->state = STATE_2PARAM_1;
+			next_state = STATE_2PARAM_1;
 			break;
 		case 0xf4:
 		case 0xf5:
-			port->state = STATE_UNKNOWN;
+			next_state = STATE_INITIAL;
 			break;
 		case 0xf6:
-			f_midi_transmit_packet(req, p0 | 0x05, 0xf6, 0, 0);
-			port->state = STATE_UNKNOWN;
-			break;
-		case 0xf7:
-			switch (port->state) {
-			case STATE_SYSEX_0:
-				f_midi_transmit_packet(req,
-					p0 | 0x05, 0xf7, 0, 0);
-				break;
-			case STATE_SYSEX_1:
-				f_midi_transmit_packet(req,
-					p0 | 0x06, port->data[0], 0xf7, 0);
-				break;
-			case STATE_SYSEX_2:
-				f_midi_transmit_packet(req,
-					p0 | 0x07, port->data[0],
-					port->data[1], 0xf7);
-				break;
-			}
-			port->state = STATE_UNKNOWN;
+			p[0] |= 0x05;
+			p[1] = 0xf6;
+			next_state = STATE_FINISHED;
 			break;
 		}
-	} else if (b >= 0x80) {
+		break;
+
+	case 0x80 ... 0xef:
+		/*
+		 * Channel Voice Messages, Channel Mode Messages
+		 * and Control Change Messages.
+		 */
 		port->data[0] = b;
+		port->data[1] = 0;
+		port->state = STATE_INITIAL;
 		if (b >= 0xc0 && b <= 0xdf)
-			port->state = STATE_1PARAM;
+			next_state = STATE_1PARAM;
 		else
-			port->state = STATE_2PARAM_1;
-	} else { /* b < 0x80 */
+			next_state = STATE_2PARAM_1;
+		break;
+
+	case 0x00 ... 0x7f:
+		/* Message parameters */
 		switch (port->state) {
 		case STATE_1PARAM:
-			if (port->data[0] < 0xf0) {
-				p0 |= port->data[0] >> 4;
-			} else {
-				p0 |= 0x02;
-				port->state = STATE_UNKNOWN;
-			}
-			f_midi_transmit_packet(req, p0, port->data[0], b, 0);
+			if (port->data[0] < 0xf0)
+				p[0] |= port->data[0] >> 4;
+			else
+				p[0] |= 0x02;
+
+			p[1] = port->data[0];
+			p[2] = b;
+			/* This is to allow Running State Messages */
+			next_state = STATE_1PARAM;
 			break;
 		case STATE_2PARAM_1:
 			port->data[1] = b;
-			port->state = STATE_2PARAM_2;
+			next_state = STATE_2PARAM_2;
 			break;
 		case STATE_2PARAM_2:
-			if (port->data[0] < 0xf0) {
-				p0 |= port->data[0] >> 4;
-				port->state = STATE_2PARAM_1;
-			} else {
-				p0 |= 0x03;
-				port->state = STATE_UNKNOWN;
-			}
-			f_midi_transmit_packet(req,
-				p0, port->data[0], port->data[1], b);
+			if (port->data[0] < 0xf0)
+				p[0] |= port->data[0] >> 4;
+			else
+				p[0] |= 0x03;
+
+			p[1] = port->data[0];
+			p[2] = port->data[1];
+			p[3] = b;
+			/* This is to allow Running State Messages */
+			next_state = STATE_2PARAM_1;
 			break;
 		case STATE_SYSEX_0:
 			port->data[0] = b;
-			port->state = STATE_SYSEX_1;
+			next_state = STATE_SYSEX_1;
 			break;
 		case STATE_SYSEX_1:
 			port->data[1] = b;
-			port->state = STATE_SYSEX_2;
+			next_state = STATE_SYSEX_2;
 			break;
 		case STATE_SYSEX_2:
-			f_midi_transmit_packet(req,
-				p0 | 0x04, port->data[0], port->data[1], b);
-			port->state = STATE_SYSEX_0;
+			p[0] |= 0x04;
+			p[1] = port->data[0];
+			p[2] = port->data[1];
+			p[3] = b;
+			next_state = STATE_SYSEX_0;
 			break;
 		}
+		break;
+	}
+
+	/* States where we have to write into the USB request */
+	if (next_state == STATE_FINISHED ||
+	    port->state == STATE_SYSEX_2 ||
+	    port->state == STATE_1PARAM ||
+	    port->state == STATE_2PARAM_2 ||
+	    port->state == STATE_REAL_TIME) {
+
+		unsigned int length = req->length;
+		u8 *buf = (u8 *)req->buf + length;
+
+		memcpy(buf, p, sizeof(p));
+		req->length = length + sizeof(p);
+
+		if (next_state == STATE_FINISHED) {
+			next_state = STATE_INITIAL;
+			port->data[0] = port->data[1] = 0;
+		}
 	}
+
+	port->state = next_state;
 }
 
 static void f_midi_drop_out_substreams(struct f_midi *midi)
@@ -641,7 +695,7 @@ static int f_midi_in_open(struct snd_rawmidi_substream *substream)
 	VDBG(midi, "%s()\n", __func__);
 	port = midi->in_ports_array + substream->number;
 	port->substream = substream;
-	port->state = STATE_UNKNOWN;
+	port->state = STATE_INITIAL;
 	return 0;
 }
 
-- 
2.9.0

[PATCH v3 6/9] usb: gadget: f_midi: drop substreams when disabling endpoint

[Felipe F. Tonello]

This change makes sure that the ALSA buffers are cleaned if an endpoint
becomes disabled.

Before this change, if the internal ALSA buffer did overflow, the MIDI
function would stop sending MIDI to the host.

Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>
---
 drivers/usb/gadget/function/f_midi.c | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 09d769e18b50..3a47596afcab 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -305,6 +305,19 @@ f_midi_complete(struct usb_ep *ep, struct usb_request *req)
 	}
 }
 
+static void f_midi_drop_out_substreams(struct f_midi *midi)
+{
+	unsigned int i;
+
+	for (i = 0; i < midi->in_ports; i++) {
+		struct gmidi_in_port *port = midi->in_ports_array + i;
+		struct snd_rawmidi_substream *substream = port->substream;
+
+		if (port->active && substream)
+			snd_rawmidi_drop_output(substream);
+	}
+}
+
 static int f_midi_start_ep(struct f_midi *midi,
 			   struct usb_function *f,
 			   struct usb_ep *ep)
@@ -402,6 +415,8 @@ static void f_midi_disable(struct usb_function *f)
 	/* release IN requests */
 	while (kfifo_get(&midi->in_req_fifo, &req))
 		free_ep_req(midi->in_ep, req);
+
+	f_midi_drop_out_substreams(midi);
 }
 
 static int f_midi_snd_free(struct snd_device *device)
@@ -571,18 +586,6 @@ static void f_midi_transmit_byte(struct usb_request *req,
 	port->state = next_state;
 }
 
-static void f_midi_drop_out_substreams(struct f_midi *midi)
-{
-	unsigned int i;
-
-	for (i = 0; i < midi->in_ports; i++) {
-		struct gmidi_in_port *port = midi->in_ports_array + i;
-		struct snd_rawmidi_substream *substream = port->substream;
-		if (port->active && substream)
-			snd_rawmidi_drop_output(substream);
-	}
-}
-
 static int f_midi_do_transmit(struct f_midi *midi, struct usb_ep *ep)
 {
 	struct usb_request *req = NULL;
-- 
2.9.0

[PATCH v3 7/9] usb: gadget: remove useless parameter in alloc_ep_req()

[Felipe F. Tonello]

The default_length parameter of alloc_ep_req was not really necessary
and gadget drivers would almost always create an inline function to pass
the same value to len and default_len.

So this patch also removes duplicate code from few drivers.

Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>
---
 drivers/usb/gadget/function/f_hid.c        | 10 ++--------
 drivers/usb/gadget/function/f_loopback.c   |  9 +--------
 drivers/usb/gadget/function/f_midi.c       | 10 ++--------
 drivers/usb/gadget/function/f_sourcesink.c | 11 ++---------
 drivers/usb/gadget/u_f.c                   |  7 +++----
 drivers/usb/gadget/u_f.h                   |  3 +--
 6 files changed, 11 insertions(+), 39 deletions(-)

diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index 51980c50546d..e82a7468252e 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -362,12 +362,6 @@ static int f_hidg_open(struct inode *inode, struct file *fd)
 /*-------------------------------------------------------------------------*/
 /*                                usb_function                             */
 
-static inline struct usb_request *hidg_alloc_ep_req(struct usb_ep *ep,
-						    unsigned length)
-{
-	return alloc_ep_req(ep, length, length);
-}
-
 static void hidg_set_report_complete(struct usb_ep *ep, struct usb_request *req)
 {
 	struct f_hidg *hidg = (struct f_hidg *) req->context;
@@ -549,8 +543,8 @@ static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 		 */
 		for (i = 0; i < hidg->qlen && status == 0; i++) {
 			struct usb_request *req =
-					hidg_alloc_ep_req(hidg->out_ep,
-							  hidg->report_length);
+				alloc_ep_req(hidg->out_ep,
+					hidg->report_length);
 			if (req) {
 				req->complete = hidg_set_report_complete;
 				req->context  = hidg;
diff --git a/drivers/usb/gadget/function/f_loopback.c b/drivers/usb/gadget/function/f_loopback.c
index 3a9f8f9c77bd..701ee0f11c33 100644
--- a/drivers/usb/gadget/function/f_loopback.c
+++ b/drivers/usb/gadget/function/f_loopback.c
@@ -306,13 +306,6 @@ static void disable_loopback(struct f_loopback *loop)
 	VDBG(cdev, "%s disabled\n", loop->function.name);
 }
 
-static inline struct usb_request *lb_alloc_ep_req(struct usb_ep *ep, int len)
-{
-	struct f_loopback	*loop = ep->driver_data;
-
-	return alloc_ep_req(ep, len, loop->buflen);
-}
-
 static int alloc_requests(struct usb_composite_dev *cdev,
 			  struct f_loopback *loop)
 {
@@ -333,7 +326,7 @@ static int alloc_requests(struct usb_composite_dev *cdev,
 		if (!in_req)
 			goto fail;
 
-		out_req = lb_alloc_ep_req(loop->out_ep, 0);
+		out_req = alloc_ep_req(loop->out_ep, loop->buflen);
 		if (!out_req)
 			goto fail_in;
 
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 3a47596afcab..abf26364b46f 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -208,12 +208,6 @@ static struct usb_gadget_strings *midi_strings[] = {
 	NULL,
 };
 
-static inline struct usb_request *midi_alloc_ep_req(struct usb_ep *ep,
-						    unsigned length)
-{
-	return alloc_ep_req(ep, length, length);
-}
-
 static const uint8_t f_midi_cin_length[] = {
 	0, 0, 2, 3, 3, 1, 2, 3, 3, 3, 3, 3, 2, 2, 3, 1
 };
@@ -365,7 +359,7 @@ static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 	/* pre-allocate write usb requests to use on f_midi_transmit. */
 	while (kfifo_avail(&midi->in_req_fifo)) {
 		struct usb_request *req =
-			midi_alloc_ep_req(midi->in_ep, midi->buflen);
+			alloc_ep_req(midi->in_ep, midi->buflen);
 
 		if (req == NULL)
 			return -ENOMEM;
@@ -379,7 +373,7 @@ static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 	/* allocate a bunch of read buffers and queue them all at once. */
 	for (i = 0; i < midi->qlen && err == 0; i++) {
 		struct usb_request *req =
-			midi_alloc_ep_req(midi->out_ep, midi->buflen);
+			alloc_ep_req(midi->out_ep, midi->buflen);
 
 		if (req == NULL)
 			return -ENOMEM;
diff --git a/drivers/usb/gadget/function/f_sourcesink.c b/drivers/usb/gadget/function/f_sourcesink.c
index df0189ddfdd5..517d78d6da78 100644
--- a/drivers/usb/gadget/function/f_sourcesink.c
+++ b/drivers/usb/gadget/function/f_sourcesink.c
@@ -291,13 +291,6 @@ static struct usb_gadget_strings *sourcesink_strings[] = {
 
 /*-------------------------------------------------------------------------*/
 
-static inline struct usb_request *ss_alloc_ep_req(struct usb_ep *ep, int len)
-{
-	struct f_sourcesink		*ss = ep->driver_data;
-
-	return alloc_ep_req(ep, len, ss->buflen);
-}
-
 static void disable_ep(struct usb_composite_dev *cdev, struct usb_ep *ep)
 {
 	int			value;
@@ -606,11 +599,11 @@ static int source_sink_start_ep(struct f_sourcesink *ss, bool is_in,
 	} else {
 		ep = is_in ? ss->in_ep : ss->out_ep;
 		qlen = ss->bulk_qlen;
-		size = 0;
+		size = ss->buflen;
 	}
 
 	for (i = 0; i < qlen; i++) {
-		req = ss_alloc_ep_req(ep, size);
+		req = alloc_ep_req(ep, size);
 		if (!req)
 			return -ENOMEM;
 
diff --git a/drivers/usb/gadget/u_f.c b/drivers/usb/gadget/u_f.c
index d1933b0b76c3..18839732c840 100644
--- a/drivers/usb/gadget/u_f.c
+++ b/drivers/usb/gadget/u_f.c
@@ -14,15 +14,14 @@
 #include "u_f.h"
 #include <linux/usb/ch9.h>
 
-struct usb_request *alloc_ep_req(struct usb_ep *ep, int len, int default_len)
+struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len)
 {
 	struct usb_request      *req;
 
 	req = usb_ep_alloc_request(ep, GFP_ATOMIC);
 	if (req) {
-		req->length = len ?: default_len;
-		if (usb_endpoint_dir_out(ep->desc))
-			req->length = usb_ep_align(ep, req->length);
+		req->length = usb_endpoint_dir_out(ep->desc) ?
+			usb_ep_align(ep, len) : len;
 		req->buf = kmalloc(req->length, GFP_ATOMIC);
 		if (!req->buf) {
 			usb_ep_free_request(ep, req);
diff --git a/drivers/usb/gadget/u_f.h b/drivers/usb/gadget/u_f.h
index 69a1d10df04f..7d53a4773d1a 100644
--- a/drivers/usb/gadget/u_f.h
+++ b/drivers/usb/gadget/u_f.h
@@ -53,14 +53,13 @@ struct usb_request;
  *
  * @ep: the endpoint to allocate a usb_request
  * @len: usb_requests's buffer suggested size
- * @default_len: used if @len is not provided, ie, is 0
  *
  * In case @ep direction is OUT, the @len will be aligned to ep's
  * wMaxPacketSize. In order to avoid memory leaks or drops, *always* use
  * usb_requests's length (req->length) to refer to the allocated buffer size.
  * Requests allocated via alloc_ep_req() *must* be freed by free_ep_req().
  */
-struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len, int default_len);
+struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len);
 
 /* Frees a usb_request previously allocated by alloc_ep_req() */
 static inline void free_ep_req(struct usb_ep *ep, struct usb_request *req)
-- 
2.9.0

[PATCH v3 8/9] usb: gadget: f_hid: use free_ep_req()

[Felipe F. Tonello]

We should always use free_ep_req() when allocating requests with
alloc_ep_req().

Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>
---
 drivers/usb/gadget/function/f_hid.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index e82a7468252e..a010496e4e05 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -671,11 +671,8 @@ fail_free_descs:
 	usb_free_all_descriptors(f);
 fail:
 	ERROR(f->config->cdev, "hidg_bind FAILED\n");
-	if (hidg->req != NULL) {
-		kfree(hidg->req->buf);
-		if (hidg->in_ep != NULL)
-			usb_ep_free_request(hidg->in_ep, hidg->req);
-	}
+	if (hidg->req != NULL)
+		free_ep_req(hidg->in_ep, hidg->req);
 
 	return status;
 }
@@ -904,8 +901,7 @@ static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
 
 	/* disable/free request and end point */
 	usb_ep_disable(hidg->in_ep);
-	kfree(hidg->req->buf);
-	usb_ep_free_request(hidg->in_ep, hidg->req);
+	free_ep_req(hidg->in_ep, hidg->req);
 
 	usb_free_all_descriptors(f);
 }
-- 
2.9.0

[PATCH v3 9/9] usb: gadget: f_hid: use alloc_ep_req()

[Felipe F. Tonello]

Use gadget's framework allocation function instead of directly calling
usb_ep_alloc_request().

Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>
---
 drivers/usb/gadget/function/f_hid.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index a010496e4e05..89d2e9a5a04f 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -611,14 +611,10 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
 
 	/* preallocate request and buffer */
 	status = -ENOMEM;
-	hidg->req = usb_ep_alloc_request(hidg->in_ep, GFP_KERNEL);
+	hidg->req = alloc_ep_req(hidg->in_ep, hidg->report_length);
 	if (!hidg->req)
 		goto fail;
 
-	hidg->req->buf = kmalloc(hidg->report_length, GFP_KERNEL);
-	if (!hidg->req->buf)
-		goto fail;
-
 	/* set descriptor dynamic values */
 	hidg_interface_desc.bInterfaceSubClass = hidg->bInterfaceSubClass;
 	hidg_interface_desc.bInterfaceProtocol = hidg->bInterfaceProtocol;
-- 
2.9.0