Firmware: Satman skew calibration & tester

cargo template: add calibrate_wrpll_skew feature
tag collector: add TAG_OFFSET for Satman WRPLL
tag collector: add TAG_OFFSET getter & setter for calibration
wrpll: add skew tester and calibration
wrpll: gate calibration behind calibrate_wrpll_skew feature
This commit is contained in:
morgan 2024-03-19 10:36:47 +08:00
parent 291777f764
commit b81323af30
3 changed files with 138 additions and 3 deletions

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@ -10,6 +10,7 @@ name = "libboard_artiq"
[features] [features]
target_zc706 = ["libboard_zynq/target_zc706", "libconfig/target_zc706"] target_zc706 = ["libboard_zynq/target_zc706", "libconfig/target_zc706"]
target_kasli_soc = ["libboard_zynq/target_kasli_soc", "libconfig/target_kasli_soc"] target_kasli_soc = ["libboard_zynq/target_kasli_soc", "libconfig/target_kasli_soc"]
calibrate_wrpll_skew = []
[build-dependencies] [build-dependencies]
build_zynq = { path = "../libbuild_zynq" } build_zynq = { path = "../libbuild_zynq" }

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@ -355,6 +355,10 @@ pub mod wrpll {
mod tag_collector { mod tag_collector {
use super::*; use super::*;
#[cfg(wrpll_ref_clk = "GT_CDR")]
static mut TAG_OFFSET: u32 = 19050;
#[cfg(wrpll_ref_clk = "SMA_CLKIN")]
static mut TAG_OFFSET: u32 = 0;
static mut REF_TAG: u32 = 0; static mut REF_TAG: u32 = 0;
static mut REF_TAG_READY: bool = false; static mut REF_TAG_READY: bool = false;
static mut MAIN_TAG: u32 = 0; static mut MAIN_TAG: u32 = 0;
@ -392,6 +396,18 @@ pub mod wrpll {
unsafe { REF_TAG_READY && MAIN_TAG_READY } 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 { pub fn get_period_error() -> i32 {
// n * BEATING_PERIOD - REF_TAG(n) mod BEATING_PERIOD // 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 }; let mut period_error = unsafe { REF_TAG.overflowing_neg().0.rem_euclid(BEATING_PERIOD as u32) as i32 };
@ -403,9 +419,13 @@ pub mod wrpll {
} }
pub fn get_phase_error() -> i32 { pub fn get_phase_error() -> i32 {
// MAIN_TAG(n) - REF_TAG(n) mod BEATING_PERIOD // MAIN_TAG(n) - REF_TAG(n) - TAG_OFFSET mod BEATING_PERIOD
let mut phase_error = let mut phase_error = unsafe {
unsafe { MAIN_TAG.overflowing_sub(REF_TAG).0.rem_euclid(BEATING_PERIOD as u32) as i32 }; MAIN_TAG
.overflowing_sub(REF_TAG + TAG_OFFSET)
.0
.rem_euclid(BEATING_PERIOD as u32) as i32
};
// mapping tags from [0, 2π] -> [-π, π] // mapping tags from [0, 2π] -> [-π, π]
if phase_error > BEATING_HALFPERIOD { if phase_error > BEATING_HALFPERIOD {
@ -520,6 +540,113 @@ pub mod wrpll {
Ok(()) Ok(())
} }
#[cfg(wrpll_ref_clk = "GT_CDR")]
fn test_skew(timer: &mut GlobalTimer) -> Result<(), &'static str> {
// wait for PLL to stabilize
timer.delay_us(20_000);
info!("testing the skew of SYS CLK...");
if has_timing_error(timer) {
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(timer: &mut GlobalTimer) -> bool {
unsafe {
csr::wrpll_skewtester::error_write(1);
}
timer.delay_us(5_000);
unsafe { csr::wrpll_skewtester::error_read() == 1 }
}
#[cfg(feature = "calibrate_wrpll_skew")]
fn find_edge(target: bool, timer: &mut GlobalTimer) -> 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
timer.delay_us(20_000);
let error = has_timing_error(timer);
// 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(timer: &mut GlobalTimer) -> Result<(), &'static str> {
info!("calibrating skew to meet timing constraint...");
// clear calibrated value
tag_collector::set_tag_offset(0);
let rising = find_edge(true, timer)? as i32;
let falling = find_edge(false, timer)? 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, timer: &mut GlobalTimer) { pub fn select_recovered_clock(rc: bool, timer: &mut GlobalTimer) {
set_isr(false); set_isr(false);
@ -537,6 +664,12 @@ pub mod wrpll {
// use nFIQ to avoid IRQ being disabled by mutex lock and mess up PLL // use nFIQ to avoid IRQ being disabled by mutex lock and mess up PLL
set_isr(true); set_isr(true);
info!("WRPLL interrupt enabled"); info!("WRPLL interrupt enabled");
#[cfg(feature = "calibrate_wrpll_skew")]
calibrate_skew(timer).expect("failed to set the correct skew");
#[cfg(wrpll_ref_clk = "GT_CDR")]
test_skew(timer).expect("skew test failed");
} }
} }
} }

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@ -7,6 +7,7 @@ build = "build.rs"
[features] [features]
target_zc706 = ["libboard_zynq/target_zc706", "libsupport_zynq/target_zc706", "libconfig/target_zc706", "libboard_artiq/target_zc706"] target_zc706 = ["libboard_zynq/target_zc706", "libsupport_zynq/target_zc706", "libconfig/target_zc706", "libboard_artiq/target_zc706"]
target_kasli_soc = ["libboard_zynq/target_kasli_soc", "libsupport_zynq/target_kasli_soc", "libconfig/target_kasli_soc", "libboard_artiq/target_kasli_soc"] target_kasli_soc = ["libboard_zynq/target_kasli_soc", "libsupport_zynq/target_kasli_soc", "libconfig/target_kasli_soc", "libboard_artiq/target_kasli_soc"]
calibrate_wrpll_skew = ["libboard_artiq/calibrate_wrpll_skew"]
default = ["target_zc706", ] default = ["target_zc706", ]
[build-dependencies] [build-dependencies]