brcm2708: update to latest patches from RPi foundation

[openwrt/openwrt.git] / target / linux / brcm2708 / patches-4.19 / 950-0785-Pisound-MIDI-communication-fixes-for-scaled-down-CPU.patch

diff --git a/target/linux/brcm2708/patches-4.19/950-0785-Pisound-MIDI-communication-fixes-for-scaled-down-CPU.patch b/target/linux/brcm2708/patches-4.19/950-0785-Pisound-MIDI-communication-fixes-for-scaled-down-CPU.patch
new file mode 100644 (file)
index 0000000..c363e1d
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.19/950-0785-Pisound-MIDI-communication-fixes-for-scaled-down-CPU.patch
@@ -0,0 +1,100 @@
+From 5b12b655f266ea29e91a7b7a46385df05bb70ed8 Mon Sep 17 00:00:00 2001
+From: Giedrius <giedrius@blokas.io>
+Date: Tue, 7 Jan 2020 11:04:21 +0200
+Subject: [PATCH] Pisound: MIDI communication fixes for scaled down
+ CPU.
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+* Increased maximum SPI communication speed to avoid running too slow
+  when the CPU is scaled down and losing MIDI data.
+
+* Keep track of buffer usage in millibytes for higher precision.
+
+Signed-off-by: Giedrius Trainavičius <giedrius@blokas.io>
+---
+ sound/soc/bcm/pisound.c | 31 ++++++++++++++++++-------------
+ 1 file changed, 18 insertions(+), 13 deletions(-)
+
+--- a/sound/soc/bcm/pisound.c
++++ b/sound/soc/bcm/pisound.c
+@@ -1,6 +1,6 @@
+ /*
+  * Pisound Linux kernel module.
+- * Copyright (C) 2016-2019  Vilniaus Blokas UAB, https://blokas.io/pisound
++ * Copyright (C) 2016-2020  Vilniaus Blokas UAB, https://blokas.io/pisound
+  *
+  * This program is free software; you can redistribute it and/or
+  * modify it under the terms of the GNU General Public License
+@@ -326,7 +326,7 @@ static void spi_transfer(const uint8_t *
+       transfer.tx_buf = txbuf;
+       transfer.rx_buf = rxbuf;
+       transfer.len = len;
+-      transfer.speed_hz = 100000;
++      transfer.speed_hz = 150000;
+       transfer.delay_usecs = 10;
+       spi_message_add_tail(&transfer, &msg);
+ 
+@@ -403,9 +403,9 @@ static struct spi_device *pisnd_spi_find
+ static void pisnd_work_handler(struct work_struct *work)
+ {
+       enum { TRANSFER_SIZE = 4 };
+-      enum { PISOUND_OUTPUT_BUFFER_SIZE = 128 };
+-      enum { MIDI_BYTES_PER_SECOND = 3125 };
+-      int out_buffer_used = 0;
++      enum { PISOUND_OUTPUT_BUFFER_SIZE_MILLIBYTES = 127 * 1000 };
++      enum { MIDI_MILLIBYTES_PER_JIFFIE = (3125 * 1000) / HZ };
++      int out_buffer_used_millibytes = 0;
+       unsigned long now;
+       uint8_t val;
+       uint8_t txbuf[TRANSFER_SIZE];
+@@ -445,7 +445,9 @@ static void pisnd_work_handler(struct wo
+                       had_data = false;
+                       memset(txbuf, 0, sizeof(txbuf));
+                       for (i = 0; i < sizeof(txbuf) &&
+-                              out_buffer_used < PISOUND_OUTPUT_BUFFER_SIZE;
++                              ((out_buffer_used_millibytes+1000 <
++                              PISOUND_OUTPUT_BUFFER_SIZE_MILLIBYTES) ||
++                              g_ledFlashDurationChanged);
+                               i += 2) {
+ 
+                               val = 0;
+@@ -458,7 +460,7 @@ static void pisnd_work_handler(struct wo
+                               } else if (kfifo_get(&spi_fifo_out, &val)) {
+                                       txbuf[i+0] = 0x0f;
+                                       txbuf[i+1] = val;
+-                                      ++out_buffer_used;
++                                      out_buffer_used_millibytes += 1000;
+                               }
+                       }
+ 
+@@ -469,12 +471,14 @@ static void pisnd_work_handler(struct wo
+                        * rate.
+                        */
+                       now = jiffies;
+-                      out_buffer_used -=
+-                              (MIDI_BYTES_PER_SECOND / HZ) /
+-                              (now - last_transfer_at);
+-                      if (out_buffer_used < 0)
+-                              out_buffer_used = 0;
+-                      last_transfer_at = now;
++                      if (now != last_transfer_at) {
++                              out_buffer_used_millibytes -=
++                                      (now - last_transfer_at) *
++                                      MIDI_MILLIBYTES_PER_JIFFIE;
++                              if (out_buffer_used_millibytes < 0)
++                                      out_buffer_used_millibytes = 0;
++                              last_transfer_at = now;
++                      }
+ 
+                       for (i = 0; i < sizeof(rxbuf); i += 2) {
+                               if (rxbuf[i]) {
+@@ -489,6 +493,7 @@ static void pisnd_work_handler(struct wo
+                       || !kfifo_is_empty(&spi_fifo_out)
+                       || pisnd_spi_has_more()
+                       || g_ledFlashDurationChanged
++                      || out_buffer_used_millibytes != 0
+                       );
+ 
+               if (!kfifo_is_empty(&spi_fifo_in) && g_recvCallback)