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Firmware: WRPLL

wrpll: add tag collector to process gtx & main tags
wrpll: add frequency counter to set BASE_ADPLL
wrpll: add TAG_OFFSET and calibration for Satman
wrpll: add 100MHz & 125MHz fixed point low pass filter
wrpll: add main & helper PLL
This commit is contained in:
morgan 2024-05-24 11:13:51 +08:00 committed by Sébastien Bourdeauducq
parent 5d9bc930fe
commit 0ac0e08170
2 changed files with 400 additions and 0 deletions

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@ -25,3 +25,4 @@ proto_artiq = { path = "../libproto_artiq" }
[features] [features]
uart_console = [] uart_console = []
alloc = [] alloc = []
calibrate_wrpll_skew = []

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@ -321,3 +321,402 @@ fn set_adpll(dcxo: i2c::DCXO, adpll: i32) -> Result<(), &'static str> {
Ok(()) Ok(())
} }
#[cfg(has_wrpll)]
pub mod wrpll {
use super::*;
const BEATING_PERIOD: i32 = 0x8000;
const BEATING_HALFPERIOD: i32 = 0x4000;
const COUNTER_WIDTH: u32 = 24;
const DIV_WIDTH: u32 = 2;
// y[n] = b0*x[n] + b1*x[n-1] + b2*x[n-2] - a1*y[n-1] - a2*y[n-2]
struct FilterParameters {
pub b0: i64,
pub b1: i64,
pub b2: i64,
pub a1: i64,
pub a2: i64,
}
#[cfg(rtio_frequency = "100.0")]
const LPF: FilterParameters = FilterParameters {
b0: 10905723400, // 0.03967479060647884 * 1 << 38
b1: 21811446800, // 0.07934958121295768 * 1 << 38
b2: 10905723400, // 0.03967479060647884 * 1 << 38
a1: -381134538612, // -1.3865593741228928 * 1 << 38
a2: 149879525269, // 0.5452585365488082 * 1 << 38
};
#[cfg(rtio_frequency = "125.0")]
const LPF: FilterParameters = FilterParameters {
b0: 19816511911, // 0.07209205036273991 * 1 << 38
b1: 39633023822, // 0.14418410072547982 * 1 << 38
b2: 19816511911, // 0.07209205036273991 * 1 << 38
a1: -168062510414, // -0.6114078511562919 * 1 << 38
a2: -27549348884, // -0.10022394739274834 * 1 << 38
};
static mut H_ADPLL1: i32 = 0;
static mut H_ADPLL2: i32 = 0;
static mut PERIOD_ERR1: i32 = 0;
static mut PERIOD_ERR2: i32 = 0;
static mut M_ADPLL1: i32 = 0;
static mut M_ADPLL2: i32 = 0;
static mut PHASE_ERR1: i32 = 0;
static mut PHASE_ERR2: i32 = 0;
static mut BASE_ADPLL: i32 = 0;
#[derive(Clone, Copy)]
pub enum ISR {
RefTag,
MainTag,
}
mod tag_collector {
use super::*;
#[cfg(wrpll_ref_clk = "GT_CDR")]
static mut TAG_OFFSET: u32 = 23890;
#[cfg(wrpll_ref_clk = "SMA_CLKIN")]
static mut TAG_OFFSET: u32 = 0;
static mut REF_TAG: u32 = 0;
static mut REF_TAG_READY: bool = false;
static mut MAIN_TAG: u32 = 0;
static mut MAIN_TAG_READY: bool = false;
pub fn reset() {
clear_phase_diff_ready();
unsafe {
REF_TAG = 0;
MAIN_TAG = 0;
}
}
pub fn clear_phase_diff_ready() {
unsafe {
REF_TAG_READY = false;
MAIN_TAG_READY = false;
}
}
pub fn collect_tags(interrupt: ISR) {
match interrupt {
ISR::RefTag => unsafe {
REF_TAG = csr::wrpll::ref_tag_read();
REF_TAG_READY = true;
},
ISR::MainTag => unsafe {
MAIN_TAG = csr::wrpll::main_tag_read();
MAIN_TAG_READY = true;
},
}
}
pub fn phase_diff_ready() -> bool {
unsafe { REF_TAG_READY && MAIN_TAG_READY }
}
#[cfg(feature = "calibrate_wrpll_skew")]
pub fn set_tag_offset(offset: u32) {
unsafe {
TAG_OFFSET = offset;
}
}
#[cfg(feature = "calibrate_wrpll_skew")]
pub fn get_tag_offset() -> u32 {
unsafe { TAG_OFFSET }
}
pub fn get_period_error() -> i32 {
// n * BEATING_PERIOD - REF_TAG(n) mod BEATING_PERIOD
let mut period_error = unsafe {
REF_TAG
.overflowing_neg()
.0
.rem_euclid(BEATING_PERIOD as u32) as i32
};
// mapping tags from [0, 2π] -> [-π, π]
if period_error > BEATING_HALFPERIOD {
period_error -= BEATING_PERIOD
}
period_error
}
pub fn get_phase_error() -> i32 {
// MAIN_TAG(n) - REF_TAG(n) - TAG_OFFSET mod BEATING_PERIOD
let mut phase_error = unsafe {
MAIN_TAG
.overflowing_sub(REF_TAG + TAG_OFFSET)
.0
.rem_euclid(BEATING_PERIOD as u32) as i32
};
// mapping tags from [0, 2π] -> [-π, π]
if phase_error > BEATING_HALFPERIOD {
phase_error -= BEATING_PERIOD
}
phase_error
}
}
fn set_isr(en: bool) {
let val = if en { 1 } else { 0 };
unsafe {
csr::wrpll::ref_tag_ev_enable_write(val);
csr::wrpll::main_tag_ev_enable_write(val);
}
}
fn set_base_adpll() -> Result<(), &'static str> {
let count2adpll = |error: i32| {
((error as f64 * 1e6) / (0.0001164 * (1 << (COUNTER_WIDTH - DIV_WIDTH)) as f64)) as i32
};
let (ref_count, main_count) = get_freq_counts();
unsafe {
BASE_ADPLL = count2adpll(ref_count as i32 - main_count as i32);
set_adpll(i2c::DCXO::Main, BASE_ADPLL)?;
set_adpll(i2c::DCXO::Helper, BASE_ADPLL)?;
}
Ok(())
}
fn get_freq_counts() -> (u32, u32) {
unsafe {
csr::wrpll::frequency_counter_update_write(1);
while csr::wrpll::frequency_counter_busy_read() == 1 {}
#[cfg(wrpll_ref_clk = "GT_CDR")]
let ref_count = csr::wrpll::frequency_counter_counter_rtio_rx0_read();
#[cfg(wrpll_ref_clk = "SMA_CLKIN")]
let ref_count = csr::wrpll::frequency_counter_counter_ref_read();
let main_count = csr::wrpll::frequency_counter_counter_sys_read();
(ref_count, main_count)
}
}
fn reset_plls() -> Result<(), &'static str> {
unsafe {
H_ADPLL1 = 0;
H_ADPLL2 = 0;
PERIOD_ERR1 = 0;
PERIOD_ERR2 = 0;
M_ADPLL1 = 0;
M_ADPLL2 = 0;
PHASE_ERR1 = 0;
PHASE_ERR2 = 0;
}
set_adpll(i2c::DCXO::Main, 0)?;
set_adpll(i2c::DCXO::Helper, 0)?;
// wait for adpll to transfer and DCXO to settle
clock::spin_us(200);
Ok(())
}
fn clear_pending(interrupt: ISR) {
match interrupt {
ISR::RefTag => unsafe { csr::wrpll::ref_tag_ev_pending_write(1) },
ISR::MainTag => unsafe { csr::wrpll::main_tag_ev_pending_write(1) },
};
}
fn is_pending(interrupt: ISR) -> bool {
match interrupt {
ISR::RefTag => unsafe { csr::wrpll::ref_tag_ev_pending_read() == 1 },
ISR::MainTag => unsafe { csr::wrpll::main_tag_ev_pending_read() == 1 },
}
}
pub fn interrupt_handler() {
if is_pending(ISR::RefTag) {
tag_collector::collect_tags(ISR::RefTag);
clear_pending(ISR::RefTag);
helper_pll().expect("failed to run helper DCXO PLL");
}
if is_pending(ISR::MainTag) {
tag_collector::collect_tags(ISR::MainTag);
clear_pending(ISR::MainTag);
}
if tag_collector::phase_diff_ready() {
main_pll().expect("failed to run main DCXO PLL");
tag_collector::clear_phase_diff_ready();
}
}
fn helper_pll() -> Result<(), &'static str> {
let period_err = tag_collector::get_period_error();
unsafe {
let adpll = (((LPF.b0 * period_err as i64)
+ (LPF.b1 * PERIOD_ERR1 as i64)
+ (LPF.b2 * PERIOD_ERR2 as i64)
- (LPF.a1 * H_ADPLL1 as i64)
- (LPF.a2 * H_ADPLL2 as i64))
>> 38) as i32;
set_adpll(i2c::DCXO::Helper, BASE_ADPLL + adpll)?;
H_ADPLL2 = H_ADPLL1;
PERIOD_ERR2 = PERIOD_ERR1;
H_ADPLL1 = adpll;
PERIOD_ERR1 = period_err;
};
Ok(())
}
fn main_pll() -> Result<(), &'static str> {
let phase_err = tag_collector::get_phase_error();
unsafe {
let adpll = (((LPF.b0 * phase_err as i64)
+ (LPF.b1 * PHASE_ERR1 as i64)
+ (LPF.b2 * PHASE_ERR2 as i64)
- (LPF.a1 * M_ADPLL1 as i64)
- (LPF.a2 * M_ADPLL2 as i64))
>> 38) as i32;
set_adpll(i2c::DCXO::Main, BASE_ADPLL + adpll)?;
M_ADPLL2 = M_ADPLL1;
PHASE_ERR2 = PHASE_ERR1;
M_ADPLL1 = adpll;
PHASE_ERR1 = phase_err;
};
Ok(())
}
#[cfg(wrpll_ref_clk = "GT_CDR")]
fn test_skew() -> Result<(), &'static str> {
// wait for PLL to stabilize
clock::spin_us(20_000);
info!("testing the skew of SYS CLK...");
if has_timing_error() {
return Err("the skew cannot satisfy setup/hold time constraint of RX synchronizer");
}
info!("the skew of SYS CLK met the timing constraint");
Ok(())
}
#[cfg(wrpll_ref_clk = "GT_CDR")]
fn has_timing_error() -> bool {
unsafe {
csr::wrpll_skewtester::error_write(1);
}
clock::spin_us(5_000);
unsafe { csr::wrpll_skewtester::error_read() == 1 }
}
#[cfg(feature = "calibrate_wrpll_skew")]
fn find_edge(target: bool) -> Result<u32, &'static str> {
const STEP: u32 = 8;
const STABLE_THRESHOLD: u32 = 10;
enum FSM {
Init,
WaitEdge,
GotEdge,
}
let mut state: FSM = FSM::Init;
let mut offset: u32 = tag_collector::get_tag_offset();
let mut median_edge: u32 = 0;
let mut stable_counter: u32 = 0;
for _ in 0..(BEATING_PERIOD as u32 / STEP) as usize {
tag_collector::set_tag_offset(offset);
offset += STEP;
// wait for PLL to stabilize
clock::spin_us(20_000);
let error = has_timing_error();
// A median edge deglitcher
match state {
FSM::Init => {
if error != target {
stable_counter += 1;
} else {
stable_counter = 0;
}
if stable_counter >= STABLE_THRESHOLD {
state = FSM::WaitEdge;
stable_counter = 0;
}
}
FSM::WaitEdge => {
if error == target {
state = FSM::GotEdge;
median_edge = offset;
}
}
FSM::GotEdge => {
if error != target {
median_edge += STEP;
stable_counter = 0;
} else {
stable_counter += 1;
}
if stable_counter >= STABLE_THRESHOLD {
return Ok(median_edge);
}
}
}
}
return Err("failed to find timing error edge");
}
#[cfg(feature = "calibrate_wrpll_skew")]
fn calibrate_skew() -> Result<(), &'static str> {
info!("calibrating skew to meet timing constraint...");
// clear calibrated value
tag_collector::set_tag_offset(0);
let rising = find_edge(true)? as i32;
let falling = find_edge(false)? as i32;
let width = BEATING_PERIOD - (falling - rising);
let result = falling + width / 2;
tag_collector::set_tag_offset(result as u32);
info!(
"calibration successful, error zone: {} -> {}, width: {} ({}deg), middle of working region: {}",
rising,
falling,
width,
360 * width / BEATING_PERIOD,
result,
);
Ok(())
}
pub fn select_recovered_clock(rc: bool) {
set_isr(false);
if rc {
tag_collector::reset();
reset_plls().expect("failed to reset main and helper PLL");
// get within capture range
set_base_adpll().expect("failed to set base adpll");
// clear gateware pending flag
clear_pending(ISR::RefTag);
clear_pending(ISR::MainTag);
// use nFIQ to avoid IRQ being disabled by mutex lock and mess up PLL
set_isr(true);
info!("WRPLL interrupt enabled");
#[cfg(feature = "calibrate_wrpll_skew")]
calibrate_skew().expect("failed to set the correct skew");
#[cfg(wrpll_ref_clk = "GT_CDR")]
test_skew().expect("skew test failed");
}
}
}