zynq::ddr: implement configure_iob()

src/regs.rs

@@ -35,9 +35,11 @@ macro_rules! register_common {
         }
 
         pub mod $mod_name {
+            #[derive(Clone)]
             pub struct Read {
                 pub inner: $inner,
             }
+            #[derive(Clone)]
             pub struct Write {
                 pub inner: $inner,
             }

src/zynq/ddr/mod.rs

@@ -2,7 +2,7 @@ use crate::regs::{RegisterR, RegisterW, RegisterRW};
 use super::slcr;
 use super::clocks::CpuClocks;
 
-/// Micron MT41J256M8HX-15E: 667 MHz
+/// Micron MT41J256M8HX-15E: 667 MHz DDR3
 const DDR_FREQ: u32 = 666_666_666;
 const DCI_FREQ: u32 = 10_000_000;
 
@@ -14,11 +14,14 @@ impl DdrRam {
         let clocks = CpuClocks::get();
         Self::clock_setup(&clocks);
         Self::calibrate_iob_impedance(&clocks);
+        Self::configure_iob();
 
         let ram = DdrRam {};
         ram
     }
 
+    /// Zynq-7000 AP SoC Technical Reference Manual:
+    /// 10.6.1 DDR Clock Initialization
     fn clock_setup(clocks: &CpuClocks) {
         let ddr3x_clk_divisor = ((clocks.ddr - 1) / DDR_FREQ + 1).min(255) as u8;
         let ddr2x_clk_divisor = 3 * ddr3x_clk_divisor / 2;
@@ -38,6 +41,8 @@ impl DdrRam {
         });
     }
 
+    /// Zynq-7000 AP SoC Technical Reference Manual:
+    /// 10.6.2 DDR IOB Impedance Calibration
     fn calibrate_iob_impedance(clocks: &CpuClocks) {
         let divisor0 = (clocks.ddr / DCI_FREQ)
             .max(1).min(63) as u8;
@@ -80,4 +85,49 @@ impl DdrRam {
             while ! slcr.ddriob_dci_status.read().done() {}
         });
     }
+
+    /// Zynq-7000 AP SoC Technical Reference Manual:
+    /// 10.6.3 DDR IOB Configuration
+    fn configure_iob() {
+        slcr::RegisterBlock::unlocked(|slcr| {
+            let addr_config = slcr::DdriobConfig::zeroed()
+                .output_en(slcr::DdriobOutputEn::Obuf);
+            slcr.ddriob_addr0.write(addr_config.clone());
+            slcr.ddriob_addr1.write(addr_config);
+            let data_config = slcr::DdriobConfig::zeroed()
+                .inp_type(slcr::DdriobInputType::VrefDifferential)
+                .term_en(true)
+                .dci_type(slcr::DdriobDciType::Termination)
+                .output_en(slcr::DdriobOutputEn::Obuf);
+            slcr.ddriob_data0.write(data_config.clone());
+            slcr.ddriob_data1.write(data_config);
+            let diff_config = slcr::DdriobConfig::zeroed()
+                .inp_type(slcr::DdriobInputType::Differential)
+                .term_en(true)
+                .dci_type(slcr::DdriobDciType::Termination)
+                .output_en(slcr::DdriobOutputEn::Obuf);
+            slcr.ddriob_diff0.write(diff_config.clone());
+            slcr.ddriob_diff1.write(diff_config);
+            slcr.ddriob_clock.write(
+                slcr::DdriobConfig::zeroed()
+                    .output_en(slcr::DdriobOutputEn::Obuf)
+            );
+
+            unsafe {
+                // Not documented in Technical Reference Manual
+                slcr.ddriob_drive_slew_addr.write(0x0018C61C);
+                slcr.ddriob_drive_slew_data.write(0x00F9861C);
+                slcr.ddriob_drive_slew_diff.write(0x00F9861C);
+                slcr.ddriob_drive_slew_clock.write(0x00F9861C);
+            }
+
+            // Enable internal V[REF]
+            slcr.ddriob_ddr_ctrl.modify(|_, w| w
+                    .vref_ext_en_lower(false)
+                    .vref_ext_en_upper(false)
+                    .vref_sel(slcr::DdriobVrefSel::Vref0_75V)
+                    .vref_int_en(true)
+            );
+        });
+    }
 }

src/zynq/slcr.rs

@@ -19,6 +19,45 @@ pub enum ArmPllSource {
     IoPll  = 0b11,
 }
 
+#[repr(u8)]
+pub enum DdriobInputType {
+    Off = 0b00,
+    /// For SSTL, HSTL
+    VrefDifferential = 0b01,
+    Differential = 0b10,
+    Lvcmos = 0b11,
+}
+
+#[repr(u8)]
+pub enum DdriobDciType {
+    /// DDR2/3L Addr and Clock
+    Disabled = 0b00,
+    /// LPDDR2
+    Drive = 0b01,
+    /// DDR2/3/3L Data and Diff
+    Termination = 0b11,
+}
+
+#[repr(u8)]
+pub enum DdriobOutputEn {
+    Ibuf = 0b00,
+    Obuf = 0b11,
+}
+
+
+#[repr(u8)]
+pub enum DdriobVrefSel {
+    /// For LPDDR2 with 1.2V IO
+    Vref0_6V,
+    /// For DDR3L with 1.35V IO
+    Vref0_675V,
+    /// For DDR3 with 1.5V IO
+    Vref0_75V,
+    /// For DDR2 with 1.8V IO
+    Vref0_9V,
+}
+
+
 #[repr(C)]
 pub struct RegisterBlock {
     pub scl: RW<u32>,
@@ -190,17 +229,18 @@ pub struct RegisterBlock {
     pub gpiob_cfg_hstl: RW<u32>,
     pub gpiob_drvr_bias_ctrl: RW<u32>,
     reserved21: [u32; 9],
-    pub ddriob_addr1: RW<u32>,
+    pub ddriob_addr0: DdriobConfig,
-    pub ddriob_data0: RW<u32>,
+    pub ddriob_addr1: DdriobConfig,
-    pub ddriob_data1: RW<u32>,
+    pub ddriob_data0: DdriobConfig,
-    pub ddriob_diff0: RW<u32>,
+    pub ddriob_data1: DdriobConfig,
-    pub ddriob_diff1: RW<u32>,
+    pub ddriob_diff0: DdriobConfig,
-    pub ddriob_clock: RW<u32>,
+    pub ddriob_diff1: DdriobConfig,
-    pub w_addr: RW<u32>,
+    pub ddriob_clock: DdriobConfig,
-    pub w_data: RW<u32>,
+    pub ddriob_drive_slew_addr: RW<u32>,
-    pub w_diff: RW<u32>,
+    pub ddriob_drive_slew_data: RW<u32>,
-    pub w_clock: RW<u32>,
+    pub ddriob_drive_slew_diff: RW<u32>,
-    pub ddriob_ddr_ctrl: RW<u32>,
+    pub ddriob_drive_slew_clock: RW<u32>,
+    pub ddriob_ddr_ctrl: DdriobDdrCtrl,
     pub ddriob_dci_ctrl: DdriobDciCtrl,
     pub ddriob_dci_status: DdriobDciStatus,
 }
@@ -463,6 +503,23 @@ mio_pin_register!(mio_pin_53, MioPin53);
 register!(gpiob_ctrl, GpiobCtrl, RW, u32);
 register_bit!(gpiob_ctrl, vref_en, 0);
 
+register!(ddriob_config, DdriobConfig, RW, u32);
+register_bits_typed!(ddriob_config, inp_type, u8, DdriobInputType, 1, 2);
+register_bit!(ddriob_config, dci_update_b, 3);
+register_bit!(ddriob_config, term_en, 4);
+register_bits_typed!(ddriob_config, dci_type, u8, DdriobDciType, 5, 6);
+register_bit!(ddriob_config, ibuf_disable_mode, 7);
+register_bit!(ddriob_config, term_disable_mode, 8);
+register_bits_typed!(ddriob_config, output_en, u8, DdriobOutputEn, 9, 10);
+register_bit!(ddriob_config, pullup_en, 11);
+
+register!(ddriob_ddr_ctrl, DdriobDdrCtrl, RW, u32);
+register_bit!(ddriob_ddr_ctrl, vref_int_en, 1);
+register_bits_typed!(ddriob_ddr_ctrl, vref_sel, u8, DdriobVrefSel, 1, 4);
+register_bit!(ddriob_ddr_ctrl, vref_ext_en_lower, 5);
+register_bit!(ddriob_ddr_ctrl, vref_ext_en_upper, 6);
+register_bit!(ddriob_ddr_ctrl, refio_en, 9);
+
 register!(ddriob_dci_ctrl, DdriobDciCtrl, RW, u32);
 register_bit!(ddriob_dci_ctrl, reset, 0);
 register_bit!(ddriob_dci_ctrl, enable, 0);