zynq-rs/src/zynq/clocks.rs

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use crate::regs::{RegisterR, RegisterW, RegisterRW};
use super::slcr;
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#[cfg(feature = "target_zc706")]
const PS_CLK: u32 = 33_333_333;
#[cfg(feature = "target_cora_z7_10")]
const PS_CLK: u32 = 50_000_000;
enum CpuClockMode {
/// Clocks run in 4:2:2:1 mode
C421,
/// Clocks run in 6:3:2:1 mode
C621,
}
impl CpuClockMode {
pub fn get() -> Self {
let regs = slcr::RegisterBlock::new();
if regs.clk_621_true.read().clk_621_true() {
CpuClockMode::C621
} else {
CpuClockMode::C421
}
}
}
#[derive(Debug, Clone)]
pub struct CpuClocks {
/// ARM PLL: Recommended clock source for the CPUs and the interconnect
pub arm: u32,
/// DDR PLL: Recommended clock for the DDR DRAM controller and AXI_HP interfaces
pub ddr: u32,
/// I/O PLL: Recommended clock for I/O peripherals
pub io: u32,
}
impl CpuClocks {
pub fn get() -> Self {
let regs = slcr::RegisterBlock::new();
let arm = u32::from(regs.arm_pll_ctrl.read().pll_fdiv()) * PS_CLK;
let ddr = u32::from(regs.ddr_pll_ctrl.read().pll_fdiv()) * PS_CLK;
let io = u32::from(regs.io_pll_ctrl.read().pll_fdiv()) * PS_CLK;
CpuClocks { arm, ddr, io }
}
pub fn cpu_6x4x(&self) -> u32 {
let regs = slcr::RegisterBlock::new();
let arm_clk_ctrl = regs.arm_clk_ctrl.read();
let pll = match arm_clk_ctrl.srcsel() {
slcr::ArmPllSource::ArmPll => self.arm,
slcr::ArmPllSource::DdrPll => self.ddr,
slcr::ArmPllSource::IoPll => self.io,
};
pll / u32::from(arm_clk_ctrl.divisor())
}
pub fn cpu_3x2x(&self) -> u32 {
self.cpu_6x4x() / 2
}
pub fn cpu_2x(&self) -> u32 {
match CpuClockMode::get() {
CpuClockMode::C421 =>
self.cpu_6x4x() / 2,
CpuClockMode::C621 =>
self.cpu_6x4x() / 3,
}
}
pub fn cpu_1x(&self) -> u32 {
match CpuClockMode::get() {
CpuClockMode::C421 =>
self.cpu_6x4x() / 4,
CpuClockMode::C621 =>
self.cpu_6x4x() / 6,
}
}
pub fn uart_ref_clk(&self) -> u32 {
let regs = slcr::RegisterBlock::new();
let uart_clk_ctrl = regs.uart_clk_ctrl.read();
let pll = match uart_clk_ctrl.srcsel() {
slcr::PllSource::ArmPll =>
self.arm,
slcr::PllSource::DdrPll =>
self.ddr,
slcr::PllSource::IoPll =>
self.io,
};
pll / u32::from(uart_clk_ctrl.divisor())
}
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/// Zynq-7000 AP SoC Technical Reference Manual:
/// 25.10.4 PLLs
pub fn enable_ddr(target_clock: u32) {
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let fdiv = (target_clock / PS_CLK).min(66) as u16;
let (pll_res, pll_cp, lock_cnt) = PLL_FDIV_LOCK_PARAM.iter()
.filter(|(fdiv_max, _)| fdiv <= *fdiv_max)
.nth(0)
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.expect("PLL_FDIV_LOCK_PARAM")
.1.clone();
let slcr = slcr::RegisterBlock::new();
slcr.ddr_pll_ctrl.modify(|_, w| w
.pll_pwrdwn(false)
.pll_bypass_force(true)
.pll_fdiv(fdiv)
);
slcr.ddr_pll_cfg.write(
slcr::PllCfg::zeroed()
.pll_res(pll_res)
.pll_cp(pll_cp)
.lock_cnt(lock_cnt)
);
slcr.ddr_pll_ctrl.modify(|_, w| w
.pll_reset(true)
);
slcr.ddr_pll_ctrl.modify(|_, w| w
.pll_reset(false)
);
while ! slcr.pll_status.read().ddr_pll_lock() {}
slcr.ddr_pll_ctrl.modify(|_, w| w
.pll_bypass_force(false)
.pll_bypass_qual(false)
);
}
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}
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/// (pll_fdiv_max, (pll_cp, pll_res, lock_cnt))
const PLL_FDIV_LOCK_PARAM: &[(u16, (u8, u8, u16))] = &[
(13, (2, 6, 750)),
(14, (2, 6, 700)),
(15, (2, 6, 650)),
(16, (2, 10, 625)),
(17, (2, 10, 575)),
(18, (2, 10, 550)),
(19, (2, 10, 525)),
(20, (2, 12, 500)),
(21, (2, 12, 475)),
(22, (2, 12, 450)),
(23, (2, 12, 425)),
(25, (2, 12, 400)),
(26, (2, 12, 375)),
(28, (2, 12, 350)),
(30, (2, 12, 325)),
(33, (2, 2, 300)),
(36, (2, 2, 275)),
(40, (2, 2, 250)),
(47, (3, 12, 250)),
(66, (2, 4, 250)),
];