mirror of
git://projects.qi-hardware.com/wernermisc.git
synced 2024-12-21 08:09:53 +02:00
57 lines
1.6 KiB
Diff
57 lines
1.6 KiB
Diff
This patch moves MIDI message detection from higher layers to the MIDI
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interrupt handler. This way, MIDI receivers only need to wake up once
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per complete message and not for every single byte.
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The /dev/midi queue size is changed from 64 bytes to 32 messages
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(typically 3 bytes each).
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Index: rtems/c/src/lib/libbsp/lm32/shared/milkymist_midi/midi.c
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===================================================================
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--- rtems.orig/c/src/lib/libbsp/lm32/shared/milkymist_midi/midi.c 2011-12-01 19:45:37.000000000 -0300
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+++ rtems/c/src/lib/libbsp/lm32/shared/milkymist_midi/midi.c 2011-12-02 16:05:30.000000000 -0300
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@@ -26,6 +26,8 @@
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#define DEVICE_NAME "/dev/midi"
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static rtems_id midi_q;
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+static unsigned char *midi_p = NULL;
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+static unsigned char midi_msg[3];
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static rtems_isr interrupt_handler(rtems_vector_number n)
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{
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@@ -34,7 +36,23 @@
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while (MM_READ(MM_MIDI_STAT) & MIDI_STAT_RX_EVT) {
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msg = MM_READ(MM_MIDI_RXTX);
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MM_WRITE(MM_MIDI_STAT, MIDI_STAT_RX_EVT);
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- rtems_message_queue_send(midi_q, &msg, 1);
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+
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+ if ((msg & 0xf8) == 0xf8)
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+ continue; /* ignore system real-time */
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+
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+ if (msg & 0x80)
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+ midi_p = midi_msg; /* status byte */
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+
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+ if (!midi_p)
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+ continue; /* ignore extra or unsynchronized data */
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+
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+ *midi_p++ = msg;
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+
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+ if (midi_p == midi_msg+3) {
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+ /* received a complete MIDI message */
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+ rtems_message_queue_send(midi_q, midi_msg, 3);
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+ midi_p = NULL;
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+ }
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}
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lm32_interrupt_ack(1 << MM_IRQ_MIDI);
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}
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@@ -53,8 +71,8 @@
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sc = rtems_message_queue_create(
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rtems_build_name('M', 'I', 'D', 'I'),
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- 64,
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- 1,
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+ 32,
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+ 3,
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0,
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&midi_q
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);
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