ALSA: ump: Export MIDI1 / UMP conversion helpers

Yet more preliminary work for the upcoming USB gadget support.

Now export the helpers to convert between legacy MIDI1 and UMP data
for handling the MIDI 1.0 USB interface.  The header file is moved to
include/sound.

The API functions are slightly changed, so that they can be used
without the direct access to snd_ump object.  The allocation is done
in ump.c itself as it's a simple kcalloc().

Link: https://lore.kernel.org/r/20230623075530.10976-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/ump_convert.h → include/sound/ump_convert.h

 // SPDX-License-Identifier: GPL-2.0-or-later
-#ifndef __UMP_CONVERT_H
-#define __UMP_CONVERT_H
+#ifndef __SOUND_UMP_CONVERT_H
+#define __SOUND_UMP_CONVERT_H
 
 #include <sound/ump_msg.h>
 
@@ -31,13 +31,16 @@ struct ump_cvt_to_ump {
 	struct ump_cvt_to_ump_bank bank[16];	/* per channel */
 };
 
-int snd_ump_convert_init(struct snd_ump_endpoint *ump);
-void snd_ump_convert_free(struct snd_ump_endpoint *ump);
-int snd_ump_convert_from_ump(struct snd_ump_endpoint *ump,
-			     const u32 *data, unsigned char *dst,
+int snd_ump_convert_from_ump(const u32 *data, unsigned char *dst,
 			     unsigned char *group_ret);
-void snd_ump_convert_to_ump(struct snd_ump_endpoint *ump,
-			    unsigned char group, unsigned char c);
-void snd_ump_reset_convert_to_ump(struct snd_ump_endpoint *ump,
-				  unsigned char group);
-#endif /* __UMP_CONVERT_H */
+void snd_ump_convert_to_ump(struct ump_cvt_to_ump *cvt, unsigned char group,
+			    unsigned int protocol, unsigned char c);
+
+/* reset the converter context, called at each open to ump */
+static inline void snd_ump_convert_reset(struct ump_cvt_to_ump *ctx)
+{
+	memset(ctx, 0, sizeof(*ctx));
+
+}
+
+#endif /* __SOUND_UMP_CONVERT_H */

sound/core/ump.c

@@ -11,7 +11,7 @@
 #include <sound/core.h>
 #include <sound/rawmidi.h>
 #include <sound/ump.h>
-#include "ump_convert.h"
+#include <sound/ump_convert.h>
 
 #define ump_err(ump, fmt, args...)	dev_err(&(ump)->core.dev, fmt, ##args)
 #define ump_warn(ump, fmt, args...)	dev_warn(&(ump)->core.dev, fmt, ##args)
@@ -87,7 +87,7 @@ static void snd_ump_endpoint_free(struct snd_rawmidi *rmidi)
 		ump->private_free(ump);
 
 #if IS_ENABLED(CONFIG_SND_UMP_LEGACY_RAWMIDI)
-	snd_ump_convert_free(ump);
+	kfree(ump->out_cvts);
 #endif
 }
 
@@ -1002,7 +1002,7 @@ static int snd_ump_legacy_open(struct snd_rawmidi_substream *substream)
 				goto unlock;
 		}
 		ump->legacy_out_opens++;
-		snd_ump_reset_convert_to_ump(ump, group);
+		snd_ump_convert_reset(&ump->out_cvts[group]);
 	}
 	spin_lock_irq(&ump->legacy_locks[dir]);
 	ump->legacy_substreams[dir][group] = substream;
@@ -1091,7 +1091,7 @@ static int process_legacy_output(struct snd_ump_endpoint *ump,
 		ctx = &ump->out_cvts[group];
 		while (!ctx->ump_bytes &&
 		       snd_rawmidi_transmit(substream, &c, 1) > 0)
-			snd_ump_convert_to_ump(ump, group, c);
+			snd_ump_convert_to_ump(ctx, group, ump->info.protocol, c);
 		if (ctx->ump_bytes && ctx->ump_bytes <= count) {
 			size = ctx->ump_bytes;
 			memcpy(buffer, ctx->ump, size);
@@ -1113,7 +1113,7 @@ static void process_legacy_input(struct snd_ump_endpoint *ump, const u32 *src,
 	const int dir = SNDRV_RAWMIDI_STREAM_INPUT;
 	int size;
 
-	size = snd_ump_convert_from_ump(ump, src, buf, &group);
+	size = snd_ump_convert_from_ump(src, buf, &group);
 	if (size <= 0)
 		return;
 	spin_lock_irqsave(&ump->legacy_locks[dir], flags);
@@ -1130,9 +1130,9 @@ int snd_ump_attach_legacy_rawmidi(struct snd_ump_endpoint *ump,
 	bool input, output;
 	int err;
 
-	err = snd_ump_convert_init(ump);
-	if (err < 0)
-		return err;
+	ump->out_cvts = kcalloc(16, sizeof(*ump->out_cvts), GFP_KERNEL);
+	if (!ump->out_cvts)
+		return -ENOMEM;
 
 	input = ump->core.info_flags & SNDRV_RAWMIDI_INFO_INPUT;
 	output = ump->core.info_flags & SNDRV_RAWMIDI_INFO_OUTPUT;
@@ -1140,7 +1140,7 @@ int snd_ump_attach_legacy_rawmidi(struct snd_ump_endpoint *ump,
 			      output ? 16 : 0, input ? 16 : 0,
 			      &rmidi);
 	if (err < 0) {
-		snd_ump_convert_free(ump);
+		kfree(ump->out_cvts);
 		return err;
 	}
 

sound/core/ump_convert.c

@@ -8,7 +8,7 @@
 #include <sound/core.h>
 #include <sound/asound.h>
 #include <sound/ump.h>
-#include "ump_convert.h"
+#include <sound/ump_convert.h>
 
 /*
  * Upgrade / downgrade value bits
@@ -205,12 +205,18 @@ static int cvt_ump_sysex7_to_legacy(const u32 *data, unsigned char *buf)
 	return size;
 }
 
-/* convert from a UMP packet @data to MIDI 1.0 bytes at @buf;
- * the target group is stored at @group_ret,
- * returns the number of bytes of MIDI 1.0 stream
+/**
+ * snd_ump_convert_from_ump - convert from UMP to legacy MIDI
+ * @data: UMP packet
+ * @buf: buffer to store legacy MIDI data
+ * @group_ret: pointer to store the target group
+ *
+ * Convert from a UMP packet @data to MIDI 1.0 bytes at @buf.
+ * The target group is stored at @group_ret.
+ *
+ * The function returns the number of bytes of MIDI 1.0 stream.
  */
-int snd_ump_convert_from_ump(struct snd_ump_endpoint *ump,
-			     const u32 *data,
+int snd_ump_convert_from_ump(const u32 *data,
 			     unsigned char *buf,
 			     unsigned char *group_ret)
 {
@@ -230,6 +236,7 @@ int snd_ump_convert_from_ump(struct snd_ump_endpoint *ump,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(snd_ump_convert_from_ump);
 
 /*
  * MIDI 1 byte stream -> UMP conversion
@@ -302,10 +309,10 @@ static void fill_rpn(struct ump_cvt_to_ump_bank *cc,
 }
 
 /* convert to a MIDI 1.0 Channel Voice message */
-static int cvt_legacy_cmd_to_ump(struct snd_ump_endpoint *ump,
-				 struct ump_cvt_to_ump *cvt,
-				 unsigned char group, u32 *data,
-				 unsigned char bytes)
+static int cvt_legacy_cmd_to_ump(struct ump_cvt_to_ump *cvt,
+				 unsigned char group,
+				 unsigned int protocol,
+				 u32 *data, unsigned char bytes)
 {
 	const unsigned char *buf = cvt->buf;
 	struct ump_cvt_to_ump_bank *cc;
@@ -316,7 +323,7 @@ static int cvt_legacy_cmd_to_ump(struct snd_ump_endpoint *ump,
 	BUILD_BUG_ON(sizeof(union snd_ump_midi2_msg) != 8);
 
 	/* for MIDI 1.0 UMP, it's easy, just pack it into UMP */
-	if (ump->info.protocol & SNDRV_UMP_EP_INFO_PROTO_MIDI1) {
+	if (protocol & SNDRV_UMP_EP_INFO_PROTO_MIDI1) {
 		data[0] = ump_compose(UMP_MSG_TYPE_MIDI1_CHANNEL_VOICE,
 				      group, 0, buf[0]);
 		data[0] |= buf[1] << 8;
@@ -413,8 +420,8 @@ static int cvt_legacy_cmd_to_ump(struct snd_ump_endpoint *ump,
 	return 8;
 }
 
-static int do_convert_to_ump(struct snd_ump_endpoint *ump,
-			     unsigned char group, unsigned char c, u32 *data)
+static int do_convert_to_ump(struct ump_cvt_to_ump *cvt, unsigned char group,
+			     unsigned int protocol, unsigned char c, u32 *data)
 {
 	/* bytes for 0x80-0xf0 */
 	static unsigned char cmd_bytes[8] = {
@@ -424,7 +431,6 @@ static int do_convert_to_ump(struct snd_ump_endpoint *ump,
 	static unsigned char system_bytes[16] = {
 		0, 2, 3, 2, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1
 	};
-	struct ump_cvt_to_ump *cvt = &ump->out_cvts[group];
 	unsigned char bytes;
 
 	if (c == UMP_MIDI1_MSG_SYSEX_START) {
@@ -478,40 +484,22 @@ static int do_convert_to_ump(struct snd_ump_endpoint *ump,
 	cvt->len = 1;
 	if ((cvt->buf[0] & 0xf0) == UMP_MIDI1_MSG_REALTIME)
 		return cvt_legacy_system_to_ump(cvt, group, data);
-	return cvt_legacy_cmd_to_ump(ump, cvt, group, data, cvt->cmd_bytes);
+	return cvt_legacy_cmd_to_ump(cvt, group, protocol, data, cvt->cmd_bytes);
 }
 
-/* feed a MIDI 1.0 byte @c and convert to a UMP packet;
- * the target group is @group,
- * the result is stored in out_cvts[group].ump[] and out_cvts[group].ump_bytes
+/**
+ * snd_ump_convert_to_ump - convert legacy MIDI byte to UMP packet
+ * @cvt: converter context
+ * @group: target UMP group
+ * @protocol: target UMP protocol
+ * @c: MIDI 1.0 byte data
+ *
+ * Feed a MIDI 1.0 byte @c and convert to a UMP packet if completed.
+ * The result is stored in the buffer in @cvt.
  */
-void snd_ump_convert_to_ump(struct snd_ump_endpoint *ump,
-			    unsigned char group, unsigned char c)
+void snd_ump_convert_to_ump(struct ump_cvt_to_ump *cvt, unsigned char group,
+			    unsigned int protocol, unsigned char c)
 {
-	struct ump_cvt_to_ump *cvt = &ump->out_cvts[group];
-
-	cvt->ump_bytes = do_convert_to_ump(ump, group, c, cvt->ump);
-}
-
-/* reset the converter context, called at each open */
-void snd_ump_reset_convert_to_ump(struct snd_ump_endpoint *ump,
-				  unsigned char group)
-{
-	memset(&ump->out_cvts[group], 0, sizeof(*ump->out_cvts));
-}
-
-/* initialize converters */
-int snd_ump_convert_init(struct snd_ump_endpoint *ump)
-{
-	ump->out_cvts = kcalloc(16, sizeof(*ump->out_cvts), GFP_KERNEL);
-	if (!ump->out_cvts)
-		return -ENOMEM;
-	return 0;
-}
-
-/* release resources */
-void snd_ump_convert_free(struct snd_ump_endpoint *ump)
-{
-	kfree(ump->out_cvts);
-	ump->out_cvts = NULL;
+	cvt->ump_bytes = do_convert_to_ump(cvt, group, protocol, c, cvt->ump);
 }
+EXPORT_SYMBOL_GPL(snd_ump_convert_to_ump);