Implement ReadFlash (#15)

Author: bugadani

ld/loader.x

@@ -7,7 +7,7 @@ SECTIONS {
 
         /* The KEEP is necessary to ensure that the
          * sections don't get garbage collected by the linker.
-         * 
+         *
          * Because this is not a normal binary with an entry point,
          * the linker would just discard all the code without the
          * KEEP statement here.
@@ -43,5 +43,3 @@ SECTIONS {
         KEEP(*(DeviceData))
     } > IRAM
 }
-
-

src/api.rs

@@ -22,6 +22,11 @@ pub unsafe extern "C" fn ProgramPage(adr: u32, sz: u32, buf: *const u8) -> i32 {
     crate::ProgramPage_impl(adr, sz, buf)
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn ReadFlash(adr: u32, sz: u32, buf: *mut u8) -> i32 {
+    crate::ReadFlash_impl(adr, sz, buf)
+}
+
 #[no_mangle]
 pub unsafe extern "C" fn UnInit(fnc: u32) -> i32 {
     crate::UnInit_impl(fnc)

src/api_xtensa.rs

@@ -86,6 +86,23 @@ pub unsafe extern "C" fn ProgramPage(adr: u32, sz: u32, buf: *const u8) -> i32 {
     )
 }
 
+#[no_mangle]
+#[naked]
+pub unsafe extern "C" fn ReadFlash(adr: u32, sz: u32, buf: *mut u8) -> i32 {
+    asm!(
+        "
+        .global ReadFlash_impl
+        l32r a1, STACK_PTR
+        mov.n a6, a2
+        mov.n a7, a3
+        mov.n a8, a4
+        call4 ReadFlash_impl
+        mov.n a2, a6
+        ",
+        options(noreturn)
+    )
+}
+
 #[no_mangle]
 #[naked]
 pub unsafe extern "C" fn UnInit(fnc: u32) -> i32 {

src/flash.rs

@@ -21,7 +21,7 @@ extern "C" {
     /// address (4 byte alignment), data, length
     fn esp_rom_spiflash_write(dest_addr: u32, data: *const u8, len: u32) -> i32;
     /// address (4 byte alignment), data, length
-    // fn esp_rom_spiflash_read(src_addr: u32, data: *const u32, len: u32) -> i32;
+    fn esp_rom_spiflash_read(src_addr: u32, data: *mut u8, len: u32) -> i32;
     fn esp_rom_spiflash_read_user_cmd(status: *mut u32, cmd: u8) -> i32;
     // fn esp_rom_spiflash_unlock() -> i32;
     // fn esp_rom_spiflash_lock(); // can't find in idf defs?
@@ -71,6 +71,14 @@ pub fn write_flash(address: u32, data: &[u8]) -> i32 {
     unsafe { esp_rom_spiflash_write(address, data.as_ptr(), len) }
 }
 
+pub fn read_flash(address: u32, data: &mut [u8]) -> i32 {
+    if data.is_empty() {
+        return 0;
+    }
+    let len = data.len() as u32;
+    unsafe { esp_rom_spiflash_read(address, data.as_mut_ptr(), len) }
+}
+
 pub fn wait_for_idle() -> i32 {
     const SR_WIP: u32 = 1 << 0;
 

src/main.rs

@@ -177,6 +177,23 @@ pub unsafe extern "C" fn ProgramPage_impl(adr: u32, sz: u32, buf: *const u8) ->
     (*DECOMPRESSOR).program(adr, input)
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn ReadFlash_impl(adr: u32, sz: u32, buf: *mut u8) -> i32 {
+    if !is_inited() {
+        return ERROR_BASE_INTERNAL - 1;
+    };
+
+    if (buf as u32) % 4 != 0 {
+        dprintln!("ERROR buf not word aligned");
+        return ERROR_BASE_INTERNAL - 5;
+    }
+
+    dprintln!("READ FLASH {} bytes @ {}", sz, adr);
+
+    let buffer = core::slice::from_raw_parts_mut(buf, sz as usize);
+    crate::flash::read_flash(adr, buffer)
+}
+
 #[no_mangle]
 pub unsafe extern "C" fn UnInit_impl(_fnc: u32) -> i32 {
     if !is_inited() {