+/**
+ * @file apic.c
+ * @author Lunaixsky
+ * @brief Abstraction for Advanced Programmable Interrupts Controller (APIC)
+ * @version 0.1
+ * @date 2022-03-06
+ *
+ * @copyright Copyright (c) 2022
+ *
+ */
+#include <hal/apic.h>
+#include <hal/cpu.h>
+#include <hal/pic.h>
+#include <hal/rtc.h>
+
+#include <arch/x86/interrupts.h>
+
+#include <lunaix/spike.h>
+#include <lunaix/syslog.h>
+
+LOG_MODULE("APIC")
+
+void
+apic_setup_timer();
+
+void
+apic_setup_lvts();
+
+void
+init_apic()
+{
+ // ensure that external interrupt is disabled
+ cpu_disable_interrupt();
+
+ // Make sure the APIC is there
+ // FUTURE: Use 8259 as fallback
+ assert_msg(cpu_has_apic(), "No APIC detected!");
+
+ // As we are going to use APIC, disable the old 8259 PIC
+ pic_disable();
+
+ // Hardware enable the APIC
+ // By setting bit 11 of IA32_APIC_BASE register
+ // Note: After this point, you can't disable then re-enable it until a reset (i.e., reboot)
+ asm volatile (
+ "movl %0, %%ecx\n"
+ "rdmsr\n"
+ "orl %1, %%eax\n"
+ "wrmsr\n"
+ ::"i"(IA32_APIC_BASE_MSR), "i"(IA32_APIC_ENABLE)
+ : "eax", "ecx", "edx"
+ );
+
+ // Print the basic information of our current local APIC
+ uint32_t apic_id = apic_read_reg(APIC_IDR) >> 24;
+ uint32_t apic_ver = apic_read_reg(APIC_VER);
+
+ kprintf(KINFO "ID: %x, Version: %x, Max LVT: %u\n",
+ apic_id,
+ apic_ver & 0xff,
+ (apic_ver >> 16) & 0xff);
+
+ // initialize the local vector table (LVT)
+ apic_setup_lvts();
+
+ // initialize priority registers
+
+ // set the task priority to the lowest possible, so all external interrupts are acceptable
+ // Note, the lowest possible priority class is 2, not 0, 1, as they are reserved for
+ // internal interrupts (vector 0-31, and each p-class resposible for 16 vectors).
+ // See Intel Manual Vol. 3A, 10-29
+ apic_write_reg(APIC_TPR, APIC_PRIORITY(2, 0));
+
+ // enable APIC
+ uint32_t spiv = apic_read_reg(APIC_SPIVR);
+
+ // install our handler for spurious interrupt.
+ spiv = (spiv & ~0xff) | APIC_SPIV_APIC_ENABLE | APIC_SPIV_IV;
+ apic_write_reg(APIC_SPIVR, spiv);
+
+ // setup timer and performing calibrations
+ apic_setup_timer();
+}
+
+#define LVT_ENTRY_LINT0(vector) (LVT_DELIVERY_FIXED | vector)
+
+// Pin LINT#1 is configured for relaying NMI, but we masked it here as I think
+// it is too early for that
+// LINT#1 *must* be edge trigged (Intel manual vol3. 10-14)
+#define LVT_ENTRY_LINT1 (LVT_DELIVERY_NMI | LVT_MASKED | LVT_TRIGGER_EDGE)
+#define LVT_ENTRY_ERROR(vector) (LVT_DELIVERY_FIXED | vector)
+#define LVT_ENTRY_TIMER(vector, mode) (LVT_DELIVERY_FIXED | mode | vector)
+
+void
+apic_setup_lvts()
+{
+ apic_write_reg(APIC_LVT_LINT0, LVT_ENTRY_LINT0(APIC_LINT0_IV));
+ apic_write_reg(APIC_LVT_LINT1, LVT_ENTRY_LINT1);
+ apic_write_reg(APIC_LVT_ERROR, LVT_ENTRY_ERROR(APIC_ERROR_IV));
+}
+
+void
+temp_intr_routine_rtc_tick(const isr_param* param);
+
+void
+temp_intr_routine_apic_timer(const isr_param* param);
+
+void
+test_timer(const isr_param* param);
+
+uint32_t apic_timer_base_freq = 0;
+
+// Don't optimize them! Took me an half hour to figure that out...
+
+volatile uint32_t rtc_counter = 0;
+volatile uint8_t apic_timer_done = 0;
+
+#define APIC_CALIBRATION_CONST 0x100000
+
+void
+apic_setup_timer()
+{
+ cpu_disable_interrupt();
+
+ // Setup APIC timer
+
+ // Setup a one-shot timer, we will use this to measure the bus speed. So we can
+ // then calibrate apic timer to work at *nearly* accurate hz
+ apic_write_reg(APIC_TIMER_LVT, LVT_ENTRY_TIMER(APIC_TIMER_IV, LVT_TIMER_ONESHOT));
+
+ // Set divider to 64
+ apic_write_reg(APIC_TIMER_DCR, APIC_TIMER_DIV64);
+
+ /*
+ Timer calibration process - measure the APIC timer base frequency
+
+ step 1: setup a temporary isr for RTC timer which trigger at each tick (1024Hz)
+ step 2: setup a temporary isr for #APIC_TIMER_IV
+ step 3: setup the divider, APIC_TIMER_DCR
+ step 4: Startup RTC timer
+ step 5: Write a large value, v, to APIC_TIMER_ICR to start APIC timer
+ (this must be followed immediately after step 4)
+ step 6: issue a write to EOI and clean up.
+
+ When the APIC ICR counting down to 0 #APIC_TIMER_IV triggered, save the rtc timer's
+ counter, k, and disable RTC timer immediately (although the RTC interrupts should be
+ blocked by local APIC as we are currently busy on handling #APIC_TIMER_IV)
+
+ So the apic timer frequency F_apic in Hz can be calculate as
+ v / F_apic = k / 1024
+ => F_apic = v / k * 1024
+
+ */
+
+ apic_timer_base_freq = 0;
+ rtc_counter = 0;
+ apic_timer_done = 0;
+
+ intr_subscribe(APIC_TIMER_IV, temp_intr_routine_apic_timer);
+ intr_subscribe(RTC_TIMER_IV, temp_intr_routine_rtc_tick);
+
+
+ rtc_enable_timer(); // start RTC timer
+ apic_write_reg(APIC_TIMER_ICR, APIC_CALIBRATION_CONST); // start APIC timer
+
+ // enable interrupt, just for our RTC start ticking!
+ cpu_enable_interrupt();
+
+ wait_until(apic_timer_done);
+
+ // cpu_disable_interrupt();
+
+ assert_msg(apic_timer_base_freq, "Fail to initialize timer");
+
+ kprintf(KINFO "Timer base frequency: %u Hz\n", apic_timer_base_freq);
+
+ // cleanup
+ intr_unsubscribe(APIC_TIMER_IV, temp_intr_routine_apic_timer);
+ intr_unsubscribe(RTC_TIMER_IV, temp_intr_routine_rtc_tick);
+
+ // TODO: now setup timer with our custom frequency which we can derived from the base frequency
+ // we measured
+
+ apic_write_reg(APIC_TIMER_LVT, LVT_ENTRY_TIMER(APIC_TIMER_IV, LVT_TIMER_PERIODIC));
+ intr_subscribe(APIC_TIMER_IV, test_timer);
+
+ apic_write_reg(APIC_TIMER_ICR, apic_timer_base_freq);
+}
+
+volatile rtc_datetime datetime;
+
+void
+test_timer(const isr_param* param) {
+
+ rtc_get_datetime(&datetime);
+
+ kprintf(KWARN "%u/%02u/%02u %02u:%02u:%02u\r",
+ datetime.year,
+ datetime.month,
+ datetime.day,
+ datetime.hour,
+ datetime.minute,
+ datetime.second);
+}
+
+void
+temp_intr_routine_rtc_tick(const isr_param* param) {
+ rtc_counter++;
+
+ // dummy read on register C so RTC can send anther interrupt
+ // This strange behaviour observed in virtual box & bochs
+ (void) rtc_read_reg(RTC_REG_C);
+}
+
+void
+temp_intr_routine_apic_timer(const isr_param* param) {
+ apic_timer_base_freq = APIC_CALIBRATION_CONST / rtc_counter * RTC_TIMER_BASE_FREQUENCY;
+ apic_timer_done = 1;
+
+ rtc_disable_timer();
+}
\ No newline at end of file
git://scm.lunaixsky.com / lunaix-os.git / commitdiff