From 4f90a0f5c19c1f1902fade40bf5ffa786bc598da Mon Sep 17 00:00:00 2001
From: wartman4404 <wartman4404@users.noreply.github.com>
Date: Sun, 7 Jan 2018 16:38:39 -0600
Subject: [PATCH] Write hpet timer 0 twice to set accumulator and period
This allows booting with implementations that require them to be set separately.
Also, check for the availability of legacy-replacement mode and periodic interrupts before using hpet
---
src/arch/x86_64/device/hpet.rs | 29 ++++++++++++++++++++++++-----
src/arch/x86_64/device/mod.rs | 7 +++++--
2 files changed, 29 insertions(+), 7 deletions(-)
diff --git a/src/arch/x86_64/device/hpet.rs b/src/arch/x86_64/device/hpet.rs
index 662c1757..6f2c69bc 100644
--- a/src/arch/x86_64/device/hpet.rs
+++ b/src/arch/x86_64/device/hpet.rs
@@ -11,20 +11,39 @@ static CAPABILITY_OFFSET: usize = 0x00;
static GENERAL_CONFIG_OFFSET: usize = 0x10;
// static GENERAL_INTERRUPT_OFFSET: usize = 0x20;
// static MAIN_COUNTER_OFFSET: usize = 0xF0;
+// static NUM_TIMER_CAP_MASK: u64 = 0x0f00;
+static LEG_RT_CAP: u64 = 0x8000;
static T0_CONFIG_CAPABILITY_OFFSET: usize = 0x100;
static T0_COMPARATOR_OFFSET: usize = 0x108;
-pub unsafe fn init(hpet: &mut Hpet) {
- let counter_clk_period_fs = hpet.base_address.read_u64(CAPABILITY_OFFSET) >> 32;
+static PER_INT_CAP: u64 = 0x10;
+
+pub unsafe fn init(hpet: &mut Hpet) -> bool {
+ let capability = hpet.base_address.read_u64(CAPABILITY_OFFSET);
+ if capability & LEG_RT_CAP == 0 {
+ return false;
+ }
+
+ let counter_clk_period_fs = capability >> 32;
let desired_fs_period: u64 = 2_250_286 * 1_000_000;
let clk_periods_per_kernel_tick: u64 = desired_fs_period / counter_clk_period_fs;
- let enable_word: u64 = hpet.base_address.read_u64(GENERAL_CONFIG_OFFSET) | LEG_RT_CNF | ENABLE_CNF;
- hpet.base_address.write_u64(GENERAL_CONFIG_OFFSET, enable_word);
- // Enable interrupts from the HPET
+ let t0_capabilities = hpet.base_address.read_u64(T0_CONFIG_CAPABILITY_OFFSET);
+ if t0_capabilities & PER_INT_CAP == 0 {
+ return false;
+ }
let t0_config_word: u64 = TN_VAL_SET_CNF | TN_TYPE_CNF | TN_INT_ENB_CNF;
hpet.base_address.write_u64(T0_CONFIG_CAPABILITY_OFFSET, t0_config_word);
hpet.base_address.write_u64(T0_COMPARATOR_OFFSET, clk_periods_per_kernel_tick);
+ // set accumulator value
+ hpet.base_address.write_u64(T0_COMPARATOR_OFFSET, clk_periods_per_kernel_tick);
+ // set interval
+
+ let enable_word: u64 = hpet.base_address.read_u64(GENERAL_CONFIG_OFFSET) | LEG_RT_CNF | ENABLE_CNF;
+ hpet.base_address.write_u64(GENERAL_CONFIG_OFFSET, enable_word);
+ // Enable interrupts from the HPET
+
+ true
}
diff --git a/src/arch/x86_64/device/mod.rs b/src/arch/x86_64/device/mod.rs
index b7b9ceac..1678e739 100644
--- a/src/arch/x86_64/device/mod.rs
+++ b/src/arch/x86_64/device/mod.rs
@@ -16,9 +16,12 @@ pub unsafe fn init(active_table: &mut ActivePageTable){
pub unsafe fn init_noncore() {
{
- if let Some(ref mut hpet) = *ACPI_TABLE.hpet.write() {
- hpet::init(hpet);
+ let using_hpet = if let Some(ref mut hpet) = *ACPI_TABLE.hpet.write() {
+ hpet::init(hpet)
} else {
+ false
+ };
+ if !using_hpet {
pit::init();
}
}
--
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