Add beep sound upon pass or failure, based on PIT channel 2.

Changes by Lionel Debroux:
* disable sound output by default, and make it possible to enable it, but do intentionally not document the feature;
* improve commit message;
* fix data types;
* replace static const variables by #defines - it's a bit early to use C23 constexpr;
* make the coding style consistent with the rest of the memtest86+ code base.

app/config.c

@@ -99,6 +99,7 @@ bool            enable_sm          = true;
 bool            enable_bench       = true;
 bool            enable_mch_read    = true;
 bool            enable_numa        = false;
+bool            enable_sound       = false;
 
 bool            enable_ecc_polling = false;
 
@@ -262,6 +263,8 @@ static void parse_option(const char *option, const char *params)
         } else if (strncmp(params, "high", 5) == 0) {
             power_save = POWER_SAVE_HIGH;
         }
+    } else if (strncmp(option, "sound", 6) == 0) {
+        enable_sound = true;
     } else if (strncmp(option, "trace", 6) == 0) {
         enable_trace = true;
     } else if (strncmp(option, "usbdebug", 9) == 0) {

app/config.h

@@ -63,6 +63,7 @@ extern bool         enable_bench;
 extern bool         enable_mch_read;
 extern bool         enable_ecc_polling;
 extern bool         enable_numa;
+extern bool         enable_sound;
 
 extern bool         pause_at_start;
 

app/display.c

@@ -28,6 +28,8 @@
 
 #include "tests.h"
 
+#include "sound.h"
+
 #include "display.h"
 
 //------------------------------------------------------------------------------
@@ -397,6 +399,10 @@ void display_big_status(bool pass)
         return;
     }
 
+    if (enable_sound) {
+        sound_beep(pass);
+    }
+
     save_screen_region(POP_STATUS_REGION, popup_status_save_buffer);
 
     set_background_colour(BLACK);
@@ -576,6 +582,9 @@ void do_tick(int my_cpu)
     if (update_spinner) {
         spin_idx = (spin_idx + 1) % NUM_SPIN_STATES;
         display_spinner(spin_state[spin_idx]);
+        if (enable_sound) {
+            sound_tick_task();
+        }
     }
 
     // This only tick one time per second

app/sound.c

@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2024 Anton Ivanov (aka demiurg_spb+rigler).
+// Copyright (C) 2024 Lionel Debroux.
+#include <stdbool.h>
+#include "pit.h"
+#include "sound.h"  // self to check prototypes
+
+static bool enabled;
+static unsigned int duration;
+
+#define DURATION (7)
+
+static void beep_off()
+{
+    if (enabled) {
+        enabled = 0;
+        duration = 0;
+        pit_off();
+    }
+}
+
+static void beep_on(unsigned f_hz)
+{
+    if (!enabled) {
+        enabled = 1;
+        duration = DURATION;
+        pit_init_square_wave_generator(2, f_hz);  // pit-ch2 is connected to buzzer
+    }
+}
+
+void sound_beep(bool ok)
+{
+    #define beep_freq_ok (1100)
+    #define beep_freq_er ( 380)
+
+    beep_on(ok ? beep_freq_ok : beep_freq_er);
+}
+
+void sound_tick_task(void)
+{
+    if (duration) {
+        duration--;
+    }
+    else {
+        beep_off();
+    }
+}

app/sound.h

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef SOUND_H
+#define SOUND_H
+/**
+ * \file
+ *
+ * Provides types and variables used when performing the memory tests.
+ *
+ * Copyright (C) 2024 Anton Ivanov (aka demiurg_spb+rigler).
+ */
+
+#include <stdbool.h>
+
+void sound_beep(bool ok);
+void sound_tick_task(void);
+
+
+#endif // SOUND_H

build32/Makefile

@@ -78,6 +78,7 @@ TST_OBJS = tests/addr_walk1.o \
 
 APP_OBJS = app/badram.o \
            app/config.o \
+           app/sound.o \
            app/display.o \
            app/error.o \
            app/interrupt.o \

build64/Makefile

@@ -77,6 +77,7 @@ TST_OBJS = tests/addr_walk1.o \
 
 APP_OBJS = app/badram.o \
            app/config.o \
+           app/sound.o \
            app/display.o \
            app/error.o \
            app/interrupt.o \

system/pit.h

@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef PIT_H
+#define PIT_H
+/**
+ * \file
+ *
+ * Provides types and variables used to work with PIT
+ *
+ * This will work on real hardware and in QEMU if it started with -audiodev pa,id=speaker -machine pcspk-audiodev=speaker.
+ * The code also changes the PIT timer 2 frequency, so you will have to reset that when you're done "beep"ing :)
+ *
+ * hints:
+ *  https://wiki.osdev.org/PC_Speaker
+ *  https://wiki.osdev.org/Programmable_Interval_Timer
+ *  https://stackoverflow.com/questions/8960620/low-level-i-o-access-using-outb-and-inb
+ *  https://stackoverflow.com/questions/14194798/is-there-a-specification-of-x86-i-o-port-assignment
+ *  https://stackoverflow.com/questions/22355436/how-to-compile-32-bit-apps-on-64-bit-ubuntu
+ *
+ * outb() and friends are hardware-specific.  The value argument is
+ * passed first and the port argument is passed second, which is the
+ * opposite order from most DOS implementations.
+ *
+ * void outb(unsigned char value, unsigned short port);
+ *
+ * Copyright (C) 2024 Anton Ivanov (aka demiurg_spb+rigler).
+ * Copyright (C) 2024 Lionel Debroux.
+ */
+
+
+#include <stdint.h>
+#include <sys/io.h> // if file not found for 32bit-target in 64bit OS: "sudo apt install gcc-multilib g++-multilib"
+
+#define PIT_CH0_PORT    (0x0040U) // r/w
+#define PIT_CH1_PORT    (0x0041U) // r/w
+#define PIT_CH2_PORT    (0x0042U) // r/w
+#define PIT_CTL_PORT    (0x0043U) // write only
+#define PIT_STATUS_PORT (0x0061U)
+
+#define PIT_STATUS_MASK (0b00000011)
+
+#define _PIT_CTL_CH(x)      (((x)&3U)<<6)  // 0-ch0, 1-ch1, 2-ch2, 3-Read-back command (8254 only)
+
+#define PIT_CTL_CH0        _PIT_CTL_CH(0)
+#define PIT_CTL_CH1        _PIT_CTL_CH(1)
+#define PIT_CTL_CH2        _PIT_CTL_CH(2)
+#define PIT_CTL_READ_BACK  _PIT_CTL_CH(3)
+
+
+#define _PIT_CTL_ACCESS(x)  (((x)&3U)<<4)  // 0-Latch count value command, 1-lbyte, 2-hbyte, 3-lobyte/hibyte
+
+#define PIT_CTL_ACCESS_LATCH_CNT_VAL   _PIT_CTL_ACCESS(0)
+#define PIT_CTL_ACCESS_LBYTE           _PIT_CTL_ACCESS(1)
+#define PIT_CTL_ACCESS_HBYTE           _PIT_CTL_ACCESS(2)
+#define PIT_CTL_ACCESS_LBYTE_HBYTE     _PIT_CTL_ACCESS(3)
+
+
+#define _PIT_CTL_OP_MODE(x)  (((x)&7U)<<1)
+
+#define PIT_CTL_OP_MODE0   _PIT_CTL_OP_MODE(0) // (interrupt on terminal count)
+#define PIT_CTL_OP_MODE1   _PIT_CTL_OP_MODE(1) // (hardware re-triggerable one-shot)
+#define PIT_CTL_OP_MODE2   _PIT_CTL_OP_MODE(2) // (rate generator)
+#define PIT_CTL_OP_MODE3   _PIT_CTL_OP_MODE(3) // (square wave generator)
+#define PIT_CTL_OP_MODE4   _PIT_CTL_OP_MODE(4) // (software triggered strobe)
+#define PIT_CTL_OP_MODE5   _PIT_CTL_OP_MODE(5) // (hardware triggered strobe)
+
+
+#define _PIT_CTL_BCD_MODE(x)  ((x)&1U)
+
+#define PIT_CTL_BIN16_MODE   _PIT_CTL_BCD_MODE(0) // 16-bit binary
+#define PIT_CTL_BCD4_MODE    _PIT_CTL_BCD_MODE(1) // four-digit BCD
+
+
+static inline uint32_t pit_freq2div(unsigned frequency)
+{
+    return (uint32_t)(0.5f + 1193180.0f/frequency);
+}
+
+static inline void pit_off(void)
+{
+    const unsigned char x = inb(PIT_STATUS_PORT) & ~PIT_STATUS_MASK;
+
+    outb(x, PIT_STATUS_PORT);
+}
+
+static inline void pit_init_square_wave_generator(unsigned char ch, uint32_t frequency)
+{
+    const uint32_t clk_div = pit_freq2div(frequency);
+
+    const unsigned char cfg = PIT_CTL_OP_MODE3 | PIT_CTL_BIN16_MODE | PIT_CTL_ACCESS_LBYTE_HBYTE | _PIT_CTL_CH(ch);
+
+    const unsigned short PIT_DATA_PORT = PIT_CH0_PORT + ch;    // base + offset
+
+    outb(cfg, PIT_CTL_PORT); // 0xb6 = 0b10110110
+
+    outb((uint8_t)clk_div,      PIT_DATA_PORT); // low byte
+    outb((uint8_t)(clk_div>>8), PIT_DATA_PORT); // hi byte
+
+    unsigned char x = inb(PIT_STATUS_PORT);
+
+    if (!(x&PIT_STATUS_MASK)) {
+         outb(x|PIT_STATUS_MASK, PIT_STATUS_PORT);
+    }
+}
+
+#endif // PIT_H