continue fsbl

fsbl/src/main.rs

@@ -9,7 +9,7 @@ use log::error;
 use zynq7000_hal::{
     BootMode,
     clocks::pll::{PllConfig, configure_arm_pll, configure_ddr_pll, configure_io_pll},
-    ddr::configure_dci,
+    ddr::{calculate_dci_divisors, calibrate_iob_impedance_for_ddr3},
     time::Hertz,
 };
 use zynq7000_rt as _;
@@ -58,10 +58,11 @@ pub fn main() -> ! {
         PllConfig::new_from_target_clock(PS_CLK, DDR_CLK).unwrap(),
     );
     // Safety: Only done once here during start-up.
-    let ddr_clk = unsafe {
+    let ddr_clks = unsafe {
         zynq7000_hal::clocks::DdrClocks::new_with_2x_3x_init(DDR_CLK, u6::new(2), u6::new(3))
     };
-    configure_dci(&ddr_clk);
+    let dci_clk_cfg = calculate_dci_divisors(&ddr_clks);
+    calibrate_iob_impedance_for_ddr3(dci_clk_cfg, false);
 
     loop {
         cortex_ar::asm::nop();

zynq7000-hal/src/ddr.rs

@@ -1,41 +1,201 @@
-use arbitrary_int::u6;
+use arbitrary_int::{Number, u2, u3, u6};
-use zynq7000::slcr::clocks::DciClkCtrl;
+use zynq7000::slcr::{
+    clocks::DciClkCtrl,
+    ddriob::{DciType, DdriobConfig, InputType, OutputEnable},
+};
 
 use crate::{clocks::DdrClocks, time::Hertz};
 
 const DCI_MAX_FREQ: Hertz = Hertz::from_raw(10_000_000);
 
-pub fn calculate_dci_divisors(ddr_clk: Hertz) -> (u6, u6) {
+// These values were extracted from the ps7_init files and are not documented in the TMR.
-    let target_div = ddr_clk.raw().div_ceil(DCI_MAX_FREQ.raw());
+// zynq-rs uses the same values.. I assume they are constant.
+
+pub const DRIVE_SLEW_ADDR_CFG: u32 = 0x0018_c61c;
+pub const DRIVE_SLEW_DATA_CFG: u32 = 0x00f9_861c;
+pub const DRIVE_SLEW_DIFF_CFG: u32 = 0x00f9_861c;
+pub const DRIVE_SLEW_CLOCK_CFG: u32 = 0x00f9_861c;
+
+#[derive(Debug, Clone, Copy)]
+pub struct DciClkConfig {
+    div0: u6,
+    div1: u6,
+}
+
+pub fn calculate_dci_divisors(ddr_clks: &DdrClocks) -> DciClkConfig {
+    calculate_dci_divisors_with_ddr_clk(ddr_clks.ref_clk())
+}
+
+pub fn calculate_dci_divisors_with_ddr_clk(ddr_clk: Hertz) -> DciClkConfig {
+    let target_div = ddr_clk.raw().div_ceil(DCI_MAX_FREQ.raw());
+    let mut config = DciClkConfig {
+        div0: u6::new(u6::MAX.value() as u8),
+        div1: u6::new(u6::MAX.value() as u8),
+    };
 
-    let mut best = None;
     let mut best_error = 0;
     for divisor0 in 1..63 {
         for divisor1 in 1..63 {
             let current_div = (divisor0 as u32) * (divisor1 as u32);
             let error = current_div.abs_diff(target_div);
-            if best.is_none() || best_error > error {
+            if error < best_error {
-                best = Some((divisor0, divisor1));
+                config.div0 = u6::new(divisor0 as u8);
+                config.div1 = u6::new(divisor1 as u8);
                 best_error = error;
             }
         }
     }
-    best.map(|(div0, div1)| (u6::new(div0), u6::new(div1)))
+    config
-        .unwrap()
 }
 
 pub fn configure_dci(ddr_clk: &DdrClocks) {
-    let (divisor0, divisor1) = calculate_dci_divisors(ddr_clk.ref_clk());
+    let cfg = calculate_dci_divisors(ddr_clk);
     // Safety: Only done once here during start-up.
     unsafe {
         crate::Slcr::with(|slcr| {
             slcr.clk_ctrl().write_dci_clk_ctrl(
                 DciClkCtrl::builder()
-                    .with_divisor_1(divisor1)
+                    .with_divisor_1(cfg.div1)
-                    .with_divisor_0(divisor0)
+                    .with_divisor_0(cfg.div0)
                     .with_clk_act(true)
                     .build(),
             );
         });
     }
 }
+
+/// Calibrates the IOB impedance for DDR3 memory according to to TRM p.325, DDR IOB Impedance
+/// calibration.
+///
+/// This function will also enable the DCI clock with the provided clock configuration.
+/// You can use [calculate_dci_divisors] to calculate the divisor values for the given DDR clock,
+/// or you can hardcode the values if they are fixed.
+pub fn calibrate_iob_impedance_for_ddr3(dci_clk_cfg: DciClkConfig, poll_for_done: bool) {
+    calibrate_iob_impedance(
+        dci_clk_cfg,
+        u3::new(0),
+        u2::new(0),
+        u3::new(0b001),
+        u3::new(0),
+        u2::new(0),
+        poll_for_done,
+    );
+}
+
+/// Calibrates the IOB impedance according to to TRM p.325, DDR IOB Impedance calibration.
+///
+/// This function will also enable the DCI clock with the provided clock configuration.
+/// You can use [calculate_dci_divisors] to calculate the divisor values for the given DDR clock,
+/// or you can hardcode the values if they are fixed.
+pub fn calibrate_iob_impedance(
+    dci_clk_cfg: DciClkConfig,
+    pref_opt2: u3,
+    pref_opt1: u2,
+    nref_opt4: u3,
+    nref_opt2: u3,
+    nref_opt1: u2,
+    poll_for_done: bool,
+) {
+    let mut slcr = unsafe { crate::slcr::Slcr::steal() };
+    slcr.modify(|slcr| {
+        slcr.clk_ctrl().write_dci_clk_ctrl(
+            DciClkCtrl::builder()
+                .with_divisor_1(dci_clk_cfg.div1)
+                .with_divisor_0(dci_clk_cfg.div0)
+                .with_clk_act(true)
+                .build(),
+        );
+        let mut ddriob = slcr.ddriob();
+        ddriob.modify_dci_ctrl(|mut val| {
+            val.set_reset(true);
+            val
+        });
+        ddriob.modify_dci_ctrl(|mut val| {
+            val.set_reset(false);
+            val
+        });
+        ddriob.modify_dci_ctrl(|mut val| {
+            val.set_reset(true);
+            val
+        });
+        ddriob.modify_dci_ctrl(|mut val| {
+            val.set_pref_opt2(pref_opt2);
+            val.set_pref_opt1(pref_opt1);
+            val.set_nref_opt4(nref_opt4);
+            val.set_nref_opt2(nref_opt2);
+            val.set_nref_opt1(nref_opt1);
+            val
+        });
+        ddriob.modify_dci_ctrl(|mut val| {
+            val.set_update_control(false);
+            val
+        });
+        ddriob.modify_dci_ctrl(|mut val| {
+            val.set_enable(true);
+            val
+        });
+        if poll_for_done {
+            while !slcr.ddriob().read_dci_status().done() {
+                // Wait for the DDR IOB impedance calibration to complete.
+                cortex_ar::asm::nop();
+            }
+        }
+    });
+}
+
+pub struct DdriobConfigSet {
+    pub addr0: DdriobConfig,
+    pub addr1: DdriobConfig,
+    pub data0: DdriobConfig,
+    pub data1: DdriobConfig,
+    pub diff0: DdriobConfig,
+    pub diff1: DdriobConfig,
+    pub clock: DdriobConfig,
+}
+
+/// TODO: We could pull out the values from the ps7 init file, convert them into rust constants,
+/// and take a configuration set passed here.
+pub fn configure_iob_for_ddr3() {
+    let mut slcr = unsafe { crate::slcr::Slcr::steal() };
+    slcr.modify(|slcr| {
+        let mut ddriob = slcr.ddriob();
+        let mut addr_and_clk_cfg = DdriobConfig::new_with_raw_value(0);
+        addr_and_clk_cfg.set_output_enable(OutputEnable::OBuf);
+        ddriob.write_ddriob_addr0(addr_and_clk_cfg);
+        ddriob.write_ddriob_addr1(addr_and_clk_cfg);
+
+        let data_config = DdriobConfig::builder()
+            .with_pullup_enable(false)
+            .with_output_enable(OutputEnable::OBuf)
+            .with_term_disable_mode(false)
+            .with_ibuf_disable_mode(false)
+            .with_dci_type(DciType::DciTermination)
+            .with_termination_enable(true)
+            .with_dci_update_enable(false)
+            .with_inp_type(InputType::VRefBasedDifferentialReceiverForSstlHstl)
+            .build();
+        ddriob.write_ddriob_data0(data_config);
+        ddriob.write_ddriob_data1(data_config);
+        let diff_config = DdriobConfig::builder()
+            .with_pullup_enable(false)
+            .with_output_enable(OutputEnable::OBuf)
+            .with_term_disable_mode(false)
+            .with_ibuf_disable_mode(false)
+            .with_dci_type(DciType::DciTermination)
+            .with_termination_enable(true)
+            .with_dci_update_enable(false)
+            .with_inp_type(InputType::DifferentialInputReceiver)
+            .build();
+        ddriob.write_ddriob_diff0(diff_config);
+        ddriob.write_ddriob_diff1(diff_config);
+
+        ddriob.write_ddriob_clock(addr_and_clk_cfg);
+
+        // These values were extracted from the ps7_init files and are not documented in the TMR.
+        // zynq-rs uses the same values.. I assume they are constant.
+        ddriob.write_ddriob_drive_slew_addr(DRIVE_SLEW_ADDR_CFG);
+        ddriob.write_ddriob_drive_slew_data(DRIVE_SLEW_DATA_CFG);
+        ddriob.write_ddriob_drive_slew_diff(DRIVE_SLEW_DIFF_CFG);
+        ddriob.write_ddriob_drive_slew_clock(DRIVE_SLEW_CLOCK_CFG);
+    });
+}

zynq7000-hal/src/slcr.rs

@@ -40,8 +40,8 @@ impl Slcr {
     /// Returns a mutable reference to the SLCR MMIO block.
     ///
     /// The MMIO block will not be unlocked. However, the registers can still be read.
-    pub fn regs(&mut self) -> &mut MmioSlcr<'static> {
+    pub fn regs(&self) -> &MmioSlcr<'static> {
-        &mut self.0
+        &self.0
     }
 
     /// Modify the SLCR register.

zynq7000-hal/src/spi/mod.rs

@@ -1141,8 +1141,8 @@ pub fn reset(id: SpiId) {
 /// [configure_spi_ref_clk] can be used to configure the SPI reference clock with the calculated
 /// value.
 pub fn calculate_largest_allowed_spi_ref_clk_divisor(clks: &Clocks) -> Option<u6> {
-    let mut slcr = unsafe { Slcr::steal() };
+    let slcr = unsafe { Slcr::steal() };
-    let spi_clk_ctrl = slcr.regs().clk_ctrl().read_spi_clk_ctrl();
+    let spi_clk_ctrl = slcr.regs().clk_ctrl_shared().read_spi_clk_ctrl();
     let div = match spi_clk_ctrl.srcsel() {
         zynq7000::slcr::clocks::SrcSelIo::IoPll | zynq7000::slcr::clocks::SrcSelIo::IoPllAlt => {
             clks.io_clocks().ref_clk() / clks.arm_clocks().cpu_1x_clk()
@@ -1163,7 +1163,7 @@ pub fn calculate_largest_allowed_spi_ref_clk_divisor(clks: &Clocks) -> Option<u6
 
 pub fn configure_spi_ref_clk(clks: &mut Clocks, divisor: u6) {
     let mut slcr = unsafe { Slcr::steal() };
-    let spi_clk_ctrl = slcr.regs().clk_ctrl().read_spi_clk_ctrl();
+    let spi_clk_ctrl = slcr.regs().clk_ctrl_shared().read_spi_clk_ctrl();
     slcr.modify(|regs| {
         regs.clk_ctrl().modify_spi_clk_ctrl(|mut val| {
             val.set_divisor(divisor);

zynq7000/src/slcr/ddriob.rs

@@ -0,0 +1,139 @@
+use arbitrary_int::{u2, u3, u4};
+
+#[bitbybit::bitenum(u4, exhaustive = false)]
+pub enum VRefSel {
+    /// VREF = 0.6 V
+    Lpddr2 = 0b0001,
+    /// VREF = 0.675 V
+    Ddr3l = 0b0010,
+    /// VREF = 0.75 V
+    Ddr3 = 0b0100,
+    /// VREF = 0.9 V
+    Ddr2 = 0b1000,
+}
+
+#[bitbybit::bitfield(u32)]
+pub struct DdrControl {
+    /// Enables VRP/VRN.
+    #[bit(9, rw)]
+    refio_enable: bool,
+    #[bit(6, rw)]
+    vref_ext_en_upper_bits: bool,
+    #[bit(5, rw)]
+    vref_ext_en_lower_bits: bool,
+    #[bits(1..=4, rw)]
+    vref_sel: Option<VRefSel>,
+    #[bit(0, rw)]
+    vref_int_en: bool,
+}
+
+#[bitbybit::bitfield(u32, default = 0x00)]
+pub struct DciControl {
+    #[bit(20, rw)]
+    update_control: bool,
+    #[bits(17..=19, rw)]
+    pref_opt2: u3,
+    #[bits(14..=15, rw)]
+    pref_opt1: u2,
+    #[bits(11..=13, rw)]
+    nref_opt4: u3,
+    #[bits(8..=10, rw)]
+    nref_opt2: u3,
+    #[bits(6..=7, rw)]
+    nref_opt1: u2,
+    #[bit(1, rw)]
+    enable: bool,
+    /// Reset value 0. Should be toggled once to initialize flops in DCI system.
+    #[bit(0, rw)]
+    reset: bool,
+}
+
+#[bitbybit::bitfield(u32)]
+pub struct DciStatus {
+    #[bit(13, rw)]
+    done: bool,
+    #[bit(0, rw)]
+    lock: bool,
+}
+
+#[bitbybit::bitenum(u2, exhaustive = true)]
+#[derive(Debug)]
+pub enum OutputEnable {
+    IBuf = 0b00,
+    __Reserved0 = 0b01,
+    __Reserved1 = 0b10,
+    OBuf = 0b11,
+}
+
+#[bitbybit::bitenum(u2, exhaustive = true)]
+#[derive(Debug)]
+pub enum InputType {
+    Off = 0b00,
+    VRefBasedDifferentialReceiverForSstlHstl = 0b01,
+    DifferentialInputReceiver = 0b10,
+    LvcmosReceiver = 0b11,
+}
+
+#[bitbybit::bitenum(u2, exhaustive = true)]
+#[derive(Debug)]
+pub enum DciType {
+    Disabled = 0b00,
+    DciDrive = 0b01,
+    __Reserved = 0b10,
+    DciTermination = 0b11,
+}
+
+#[bitbybit::bitfield(u32, default = 0x0)]
+pub struct DdriobConfig {
+    #[bit(11, rw)]
+    pullup_enable: bool,
+    #[bits(9..=10, rw)]
+    output_enable: OutputEnable,
+    #[bit(8, rw)]
+    term_disable_mode: bool,
+    #[bit(7, rw)]
+    ibuf_disable_mode: bool,
+    #[bits(5..=6, rw)]
+    dci_type: DciType,
+    #[bit(4, rw)]
+    termination_enable: bool,
+    #[bit(3, rw)]
+    dci_update_enable: bool,
+    #[bits(1..=2, rw)]
+    inp_type: InputType,
+}
+
+#[derive(derive_mmio::Mmio)]
+#[repr(C)]
+pub struct DdrIoB {
+    ddriob_addr0: DdriobConfig,
+    ddriob_addr1: DdriobConfig,
+    ddriob_data0: DdriobConfig,
+    ddriob_data1: DdriobConfig,
+    ddriob_diff0: DdriobConfig,
+    ddriob_diff1: DdriobConfig,
+    ddriob_clock: DdriobConfig,
+    ddriob_drive_slew_addr: u32,
+    ddriob_drive_slew_data: u32,
+    ddriob_drive_slew_diff: u32,
+    ddriob_drive_slew_clock: u32,
+    ddr_ctrl: DdrControl,
+    dci_ctrl: DciControl,
+    dci_status: DciStatus,
+}
+
+impl DdrIoB {
+    /// Create a new handle to this peripheral.
+    ///
+    /// Writing to this register requires unlocking the SLCR registers first.
+    ///
+    /// # Safety
+    ///
+    /// If you create multiple instances of this handle at the same time, you are responsible for
+    /// ensuring that there are no read-modify-write races on any of the registers.
+    pub unsafe fn new_mmio_fixed() -> MmioDdrIoB<'static> {
+        unsafe { Self::new_mmio_at(super::SLCR_BASE_ADDR + super::DDRIOB_OFFSET) }
+    }
+}
+
+static_assertions::const_assert_eq!(core::mem::size_of::<DdrIoB>(), 0x38);

zynq7000/src/slcr/mod.rs

@@ -12,44 +12,10 @@ const GPIOB_OFFSET: usize = 0xB00;
 const DDRIOB_OFFSET: usize = 0xB40;
 
 pub mod clocks;
+pub mod ddriob;
 pub mod mio;
 pub mod reset;
 
-#[derive(derive_mmio::Mmio)]
-#[repr(C)]
-pub struct DdrIoB {
-    ddriob_addr0: u32,
-    ddriob_addr1: u32,
-    ddriob_data0: u32,
-    ddriob_data1: u32,
-    ddriob_diff0: u32,
-    ddriob_diff1: u32,
-    ddriob_clock: u32,
-    ddriob_drive_slew_addr: u32,
-    ddriob_drive_slew_data: u32,
-    ddriob_drive_slew_diff: u32,
-    ddriob_drive_slew_clock: u32,
-    ddriob_ddr_ctrl: u32,
-    ddriob_dci_ctrl: u32,
-    ddriob_dci_status: u32,
-}
-
-impl DdrIoB {
-    /// Create a new handle to this peripheral.
-    ///
-    /// Writing to this register requires unlocking the SLCR registers first.
-    ///
-    /// # Safety
-    ///
-    /// If you create multiple instances of this handle at the same time, you are responsible for
-    /// ensuring that there are no read-modify-write races on any of the registers.
-    pub unsafe fn new_mmio_fixed() -> MmioDdrIoB<'static> {
-        unsafe { Self::new_mmio_at(SLCR_BASE_ADDR + DDRIOB_OFFSET) }
-    }
-}
-
-static_assertions::const_assert_eq!(core::mem::size_of::<DdrIoB>(), 0x38);
-
 #[bitbybit::bitenum(u3, exhaustive = false)]
 pub enum VrefSel {
     Disabled = 0b000,
@@ -213,7 +179,7 @@ pub struct Slcr {
     gpiob: GpiobRegisters,
 
     #[mmio(Inner)]
-    ddriob: DdrIoB,
+    ddriob: ddriob::DdrIoB,
 }
 
 static_assertions::const_assert_eq!(core::mem::size_of::<Slcr>(), 0xB78);