inline assembly for flash

Author: romancardenas

.travis.yml

@@ -6,6 +6,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
+- Use inline assembly instead of binary blobs for flash
 
 ## [v0.12.0] - 2023-03-28
 - Update e310x-hal to v0.11 with new svd2rust generated code

CHANGELOG.md

@@ -44,10 +44,4 @@ fn main() {
 
     fs::copy("hifive1-link.x", out_dir.join("hifive1-link.x")).unwrap();
     println!("cargo:rerun-if-changed=hifive1-link.x");
-
-    // Copy library with flash setup code
-    let name = env::var("CARGO_PKG_NAME").unwrap();
-    fs::copy("bin/flash.a", out_dir.join(format!("lib{}.a", name))).unwrap();
-    println!("cargo:rustc-link-lib=static={}", name);
-    println!("cargo:rerun-if-changed=bin/flash.a");
 }

assemble.sh

@@ -3,6 +3,56 @@
 use e310x_hal::clock::Clocks;
 use e310x_hal::e310x::QSPI0;
 
+#[cfg(target_arch = "riscv32")]
+core::arch::global_asm!(
+    r#"
+    .cfi_sections .debug_frame
+
+    .section .data._setup_is25lp
+    .global _setup_is25lp
+    .cfi_startproc
+    _setup_is25lp:
+        li  a1, 0x10014000  // QSPI0 base address
+
+        // Disable mapped region
+        sw  zero,96(a1)  // fctrl.en = 0
+
+        // Construct ffmt value for 4 dummy cycles
+        li  a2, 0x00BB1447
+
+        beqz a0, 2f
+
+        // We need to set 8 dummy cycles instead of 4.
+        // Issue a "Set Read Parameters" command.
+
+        li  a0,2
+        sw  a0,24(a1)  // csmode = HOLD
+        li  a0,0xC0
+        sw  a0,72(a1)  // txdata = 0xC0
+        li  a0,0xF0
+        sw  a0,72(a1)  // txdata = 0xF0
+        sw  zero,24(a1)  // csmode = AUTO
+
+        // Discard two response bytes
+    1:  lw  a0,76(a1)
+        bltz a0,1b
+    1:  lw  a0,76(a1)
+        bltz a0,1b
+
+        addi a2,a2,0x40  // ffmt: 4 -> 8 dummy cycles
+    2:
+        sw  a2,100(a1)  // Write ffmt
+
+        // Enable mapped region
+        li  a0, 1
+        sw	a0,96(a1)  // fctrl.en = 1
+        ret
+
+    .cfi_endproc
+    .size _setup_is25lp, . - _setup_is25lp
+    "#
+);
+
 /// Configure SPI Flash interface to maximum supported speed
 #[inline(always)]
 pub fn configure_spi_flash(qspi: &QSPI0, clocks: &Clocks) {