Add ACPI Timer as the primary TSC correction source and PIT Timer as fallback

app/main.c

@@ -34,6 +34,7 @@
 #include "smbios.h"
 #include "smp.h"
 #include "temperature.h"
+#include "timers.h"
 #include "vmem.h"
 
 #include "unistd.h"
@@ -221,6 +222,8 @@ static void global_init(void)
 
     acpi_init();
 
+    timers_init();
+
     membw_init();
 
     smbios_init();
@@ -281,10 +284,9 @@ static void global_init(void)
     for (int i = 0; i < pm_map_size; i++) {
         trace(0, "pm %0*x - %0*x", 2*sizeof(uintptr_t), pm_map[i].start, 2*sizeof(uintptr_t), pm_map[i].end);
     }
-    if (rsdp_addr != 0) {
-        trace(0, "ACPI RSDP found in %s at %0*x", rsdp_source, 2*sizeof(uintptr_t), rsdp_addr);
-        trace(0, "ACPI FADT found at %0*x", 2*sizeof(uintptr_t), fadt_addr);
-        trace(0, "ACPI HPET found at %0*x", 2*sizeof(uintptr_t), hpet_addr);
+    if (acpi_config.rsdp_addr != 0) {
+        trace(0, "ACPI RSDP (v%u.%u) found in %s at %0*x", acpi_config.ver_maj, acpi_config.ver_min, rsdp_source, 2*sizeof(uintptr_t), acpi_config.rsdp_addr);
+        trace(0, "ACPI FADT found at %0*x", 2*sizeof(uintptr_t), acpi_config.fadt_addr);
     }
     if (!load_addr_ok) {
         trace(0, "Cannot relocate program. Press any key to reboot...");

build32/Makefile

@@ -33,6 +33,7 @@ SYS_OBJS = system/acpi.o \
            system/smbus.o \
            system/smp.o \
            system/temperature.o \
+           system/timers.o \
            system/uhci.o \
            system/usbhcd.o \
            system/vmem.o \

build64/Makefile

@@ -33,6 +33,7 @@ SYS_OBJS = system/acpi.o \
            system/smbus.o \
            system/smp.o \
            system/temperature.o \
+           system/timers.o \
            system/uhci.o \
            system/usbhcd.o \
            system/vmem.o \

system/acpi.c

@@ -89,7 +89,7 @@ static const efi_guid_t EFI_ACPI_2_RDSP_GUID = { 0x8868e871, 0xe4f1, 0x11d3, {0x
 
 const char *rsdp_source = "";
 
-acpi_t acpi_config = {0, 0, 0, 0, 0, 0, 0, 0, false};
+acpi_t acpi_config = {0, 0, 0, 0, 0, 0, 0, false};
 
 //------------------------------------------------------------------------------
 // Private Functions

system/acpi.h

@@ -22,10 +22,9 @@
  * A struct containing various ACPI-related infos for later uses.
  */
 
-typedef struct {
+typedef struct __attribute__ ((packed)) {
     uint8_t     ver_maj;
     uint8_t     ver_min;
-    uint64_t    test;
     uintptr_t   rsdp_addr;
     uintptr_t   madt_addr;
     uintptr_t   fadt_addr;

system/cpuinfo.c

@@ -33,7 +33,6 @@
 // Constants
 //------------------------------------------------------------------------------
 
-#define PIT_TICKS_50mS      59659       // PIT clock is 1.193182MHz
 #define BENCH_MIN_START_ADR 0x1000000   // 16MB
 
 //------------------------------------------------------------------------------
@@ -861,37 +860,6 @@ static void determine_cpu_model(void)
     }
 }
 
-static void measure_cpu_speed(void)
-{
-    if (cpuid_info.flags.rdtsc == 0) {
-        return;
-    }
-
-    // Set up timer
-    outb((inb(0x61) & ~0x02) | 0x01, 0x61);
-    outb(0xb0, 0x43);
-    outb(PIT_TICKS_50mS & 0xff, 0x42);
-    outb(PIT_TICKS_50mS >> 8, 0x42);
-
-    uint32_t start_time;
-    rdtscl(start_time);
-
-    int loops = 0;
-    do {
-        loops++;
-    } while ((inb(0x61) & 0x20) == 0);
-
-    uint32_t end_time;
-    rdtscl(end_time);
-
-    uint32_t run_time = end_time - start_time;
-
-    // Make sure we have a credible result
-    if (loops >= 4 && run_time >= 50000) {
-       clks_per_msec = run_time / 50;
-    }
-}
-
 static uint32_t memspeed(uintptr_t src, uint32_t len, int iter)
 {
     uintptr_t dst;
@@ -1084,8 +1052,6 @@ void cpuinfo_init(void)
     determine_cache_size();
 
     determine_cpu_model();
-
-    measure_cpu_speed();
 }
 
 void membw_init(void)

system/timers.c

@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2020-2022 Martin Whitaker.
+// Copyright (C) 2004-2022 Sam Demeulemeester.
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "acpi.h"
+#include "cpuid.h"
+#include "cpuinfo.h"
+#include "io.h"
+#include "tsc.h"
+
+//------------------------------------------------------------------------------
+// Constants
+//------------------------------------------------------------------------------
+
+#define PIT_TICKS_50mS      59659       // PIT clock is 1.193182MHz
+#define APIC_TICKS_50mS     178977      // APIC clock is 3.579545MHz
+#define BENCH_MIN_START_ADR 0x1000000   // 16MB
+
+//------------------------------------------------------------------------------
+// Private Functions
+//------------------------------------------------------------------------------
+
+static void correct_tsc(void)
+{
+    uint32_t start_time, end_time, run_time, counter;
+    int loops = 0;
+
+    if (cpuid_info.flags.rdtsc == 0) {
+        return;
+    }
+
+    // If available, use APIC Timer to find TSC correction factor
+    if (acpi_config.pm_is_io && acpi_config.pm_addr != 0) {
+        rdtscl(start_time);
+
+        counter = inl(acpi_config.pm_addr);
+
+        // Make sure counter is incrementing
+        if (inl(acpi_config.pm_addr) > counter) {
+
+            while (1) {
+                if (inl(acpi_config.pm_addr) > (counter + APIC_TICKS_50mS) || loops > 1000000) {
+                    break;
+                }
+                loops++;
+            }
+
+            rdtscl(end_time);
+
+            run_time = end_time - start_time;
+
+            // Make sure we have a credible result
+            if (loops >= 10 && run_time >= 50000) {
+               clks_per_msec = run_time / 50;
+               return;
+            }
+        }
+    }
+
+    // Use PIT Timer to find TSC correction factor if APIC not available
+    outb((inb(0x61) & ~0x02) | 0x01, 0x61);
+    outb(0xb0, 0x43);
+    outb(PIT_TICKS_50mS & 0xff, 0x42);
+    outb(PIT_TICKS_50mS >> 8, 0x42);
+
+    rdtscl(start_time);
+
+    loops = 0;
+    do {
+        loops++;
+    } while ((inb(0x61) & 0x20) == 0);
+
+    rdtscl(end_time);
+
+    run_time = end_time - start_time;
+
+    // Make sure we have a credible result
+    if (loops >= 4 && run_time >= 50000) {
+       clks_per_msec = run_time / 50;
+    }
+}
+
+//------------------------------------------------------------------------------
+// Public Functions
+//------------------------------------------------------------------------------
+
+void timers_init(void)
+{
+    correct_tsc();
+}

system/timers.h

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef _TIMERS_H_
+#define _TIMERS_H_
+/**
+ * \file
+ *
+ * Provides support for various timers sources
+ *
+ *//*
+ * Copyright (C) 2020-2022 Martin Whitaker.
+ * Copyright (C) 2004-2022 Sam Demeulemeester
+ */
+
+
+/**
+ * Initialize timers (to correct TSC frequency)
+ */
+void timers_init(void);
+
+#endif /* _TIMERS_H_ */