Add optiboot_x nvmctrl support to optiboot.h

minor fixes in test_dospm itself.
test_dospm (which uses only the "high level" calls to read and
write pages) now works the same (I think) on both traditional
AVR and new mega0/xTiny chips.

optiboot/examples/test_dospm/optiboot.h

@@ -2,6 +2,8 @@
  |                                                                          |
  | June 2015 by Marek Wodzinski, https://github.com/majekw                  |
  | Modified June 2016 by MCUdude, https://github.com/MCUdude                |
+ | Modified Sep 2020 for mega0/xTiny (optiboot_x)                           |
+ |  by Bill Westfield https://github.com/westfw                             |
  | Released to public domain                                                |
  |                                                                          |
  | This header file gives possibility to use SPM instruction                |
@@ -24,9 +26,18 @@
 #ifndef _OPTIBOOT_H_
 #define _OPTIBOOT_H_  1
 
+#ifdef SPMCSR
+// Mega0 does not have SPMCSR
 #include <avr/boot.h>
+#endif
 #include "Arduino.h"
 
+// figure out whether we have SPM or NVMCTRL
+#ifdef FUSE_BOOTEND
+#define USE_NVMCTRL 1
+#define NVMCTRL_CMD_COPY_gc (NVMCTRL_CMD_gm+1)  // one beyond existing commands.
+#define SPM_PAGESIZE (PROGMEM_PAGE_SIZE)
+#endif
 
 /* 
  * Main 'magic' function - enter to bootloader do_spm function
@@ -42,6 +53,7 @@
 // 'typedef' (in following line) and 'const' (few lines below)
 //   are a way to define external function at some arbitrary address
 typedef void (*do_spm_t)(uint16_t address, uint8_t command, uint16_t data);
+typedef void (*do_nvmctrl_t)(uint16_t address, uint8_t command, uint8_t data);
 
 
 /*
@@ -56,12 +68,20 @@ typedef void (*do_spm_t)(uint16_t address, uint8_t command, uint16_t data);
   typedef uint16_t optiboot_addr_t;
 #endif
 
+#ifdef USE_NVMCTRL
+// Mega0/xTiny/etc.   Bootloader is in low memory.
+  const do_spm_t do_nvmctrl = (do_spm_t)((PROGMEM_START+2)>>1);
+#else
 #if FLASHEND > 65534
   const do_spm_t do_spm = (do_spm_t)((FLASHEND-1023+2)>>1);
 #else
   const do_spm_t do_spm = (do_spm_t)((FLASHEND-511+2)>>1);
 #endif
+#endif
 
+#ifndef USE_NVMCTRL
+
+// SPM-based functions
 
 /*
  * The same as do_spm but with disable/restore interrupts state
@@ -81,14 +101,12 @@ void do_spm_cli(optiboot_addr_t address, uint8_t command, uint16_t data) {
   uint8_t eind = EIND;
   EIND = FLASHEND / 0x20000;
 #endif
-  // do_spm accepts only lower 16 bits of address
+  do_spm((address & 0xffff), command, data); // do_spm accepts only lower 16 bits of address
-  do_spm((address & 0xffff), command, data);
 #ifdef EIND
   EIND = eind;
 #endif
 #else
-  // 16 bit address - no problems to pass directly
+  do_spm(address, command, data); // 16 bit address - no problems to pass directly
-  do_spm(address, command, data);
 #endif
   SREG = sreg_save; // restore last interrupts state
 }
@@ -112,44 +130,11 @@ void optiboot_page_write(optiboot_addr_t address) {
 }
 
 
-
 /*
  * Higher level functions for reading and writing from flash 
  * See the examples for more info on how to use these functions
  */
 
-// Function to read a flash page and store it in an array (storage_array[])
-void optiboot_readPage(const uint8_t allocated_flash_space[],
-                       uint8_t storage_array[], uint16_t page,
-                       char blank_character)
-{
-  uint8_t read_character;
-  for(uint16_t j = 0; j < SPM_PAGESIZE; j++) 
-  {
-    read_character = pgm_read_byte(&allocated_flash_space[j + SPM_PAGESIZE*(page-1)]);
-    if(read_character != 0 && read_character != 255)
-      storage_array[j] = read_character; 
-    else
-      storage_array[j] = blank_character;   
-  }
-}
-
-
-// Function to read a flash page and store it in an array (storage_array[]),
-//   but without blank_character
-void optiboot_readPage(const uint8_t allocated_flash_space[],
-                       uint8_t storage_array[], uint16_t page)
-{
-  uint8_t read_character;
-  for(uint16_t j = 0; j < SPM_PAGESIZE; j++) 
-  {
-    read_character = pgm_read_byte(&allocated_flash_space[j + SPM_PAGESIZE*(page-1)]);
-    if(read_character != 0 && read_character != 255)
-      storage_array[j] = read_character;
-  }
-}
-
-
 // Function to write data to a flash page
 void optiboot_writePage(const uint8_t allocated_flash_space[],
                         uint8_t data_to_store[], uint16_t page)
@@ -175,5 +160,101 @@ void optiboot_writePage(const uint8_t allocated_flash_space[],
   optiboot_page_write((optiboot_addr_t)(void*) &allocated_flash_space[SPM_PAGESIZE*(page-1)]);
 }
 
+#else   // Newer Mega0/xTiny chips with NVMCTRL
+
+/*
+ * The same as do_nvmctrl but with disable/restore interrupts state
+ * required to succesfull execution
+ * 
+ * Currently, there are no mega0/xTint parts with more than 64k, and when there are
+ * they'll need extra effort beyond just RAMPZ :-(
+ */
+void do_nvmctrl_cli(optiboot_addr_t address, uint8_t command, uint16_t data)
+{
+  uint8_t sreg_save;
+
+  sreg_save = SREG;  // save old SREG value
+  asm volatile("cli");  // disable interrupts
+  do_nvmctrl(address, command, data); // 16 bit address - no problems to pass directly
+  SREG = sreg_save; // restore last interrupts state
+}
+
+
+// Erase page in FLASH
+void optiboot_page_erase(optiboot_addr_t address)
+{
+  // set page by writing to address.
+  do_nvmctrl(address+MAPPED_PROGMEM_START, NVMCTRL_CMD_COPY_gc, 0xFF);
+  do_nvmctrl_cli(0, NVMCTRL_CMD_PAGEERASE_gc, 0); // do actual erase
+}
+
+
+// Write word into temporary buffer
+void optiboot_page_fill(optiboot_addr_t address, uint16_t data)
+{
+  do_nvmctrl(address+MAPPED_PROGMEM_START, NVMCTRL_CMD_COPY_gc, data & 0xFF);
+  do_nvmctrl(address+MAPPED_PROGMEM_START, NVMCTRL_CMD_COPY_gc, data >> 8);
+}
+
+
+//Write temporary buffer into FLASH
+void optiboot_page_write(optiboot_addr_t address)
+{
+  do_nvmctrl_cli(address, NVMCTRL_CMD_PAGEWRITE_gc, 0);
+}
+
+
+/*
+ * Higher level functions for reading and writing from flash 
+ * See the examples for more info on how to use these functions
+ */
+
+// Function to write data to a flash page
+void optiboot_writePage(const uint8_t allocated_flash_space[],
+                        uint8_t data_to_store[], uint16_t page)
+{
+  const uint8_t *adjusted_address;
+  // Copy ram buffer to temporary flash buffer
+  for(uint16_t i = 0; i < SPM_PAGESIZE; i++)
+  {
+    adjusted_address = &allocated_flash_space[i + SPM_PAGESIZE*(page-1)];
+    adjusted_address += MAPPED_PROGMEM_START;
+    do_nvmctrl((optiboot_addr_t)(void*) adjusted_address,
+               NVMCTRL_CMD_COPY_gc, data_to_store[i]);
+  }
+  do_nvmctrl_cli(0, NVMCTRL_CMD_PAGEERASEWRITE_gc, 0);
+}
+
+#endif // USE_NVMTRL
+
+// Function to read a flash page and store it in an array (storage_array[])
+// (these can be shared between old and new AVRs.)
+void optiboot_readPage(const uint8_t allocated_flash_space[],
+                       uint8_t storage_array[], uint16_t page, char blank_character)
+{
+  uint8_t read_character;
+  for(uint16_t j = 0; j < SPM_PAGESIZE; j++)
+  {
+    read_character = pgm_read_byte(&allocated_flash_space[j + SPM_PAGESIZE*(page-1)]);
+    if(read_character != 0 && read_character != 255)
+      storage_array[j] = read_character;
+    else
+      storage_array[j] = blank_character;
+  }
+}
+
+
+// Function to read a flash page and store it in an array (storage_array[]), but without blank_character
+void optiboot_readPage(const uint8_t allocated_flash_space[],
+                       uint8_t storage_array[], uint16_t page)
+{
+  uint8_t read_character;
+  for(uint16_t j = 0; j < SPM_PAGESIZE; j++)
+  {
+    read_character = pgm_read_byte(&allocated_flash_space[j + SPM_PAGESIZE*(page-1)]);
+    if(read_character != 0 && read_character != 255)
+      storage_array[j] = read_character;
+  }
+}
 
 #endif /* _OPTIBOOT_H_ */

optiboot/examples/test_dospm/test_dospm.ino

@@ -49,7 +49,7 @@ uint16_t pageNumber;
 char returnToMenu;
 
 // The temporary data (data that's read or is about to get written) is stored here
-uint8_t ramBuffer[SPM_PAGESIZE];
+uint8_t ramBuffer[SPM_PAGESIZE+1];
 
 // This array allocates the space you'll be able to write to
 const uint8_t flashSpace[SPM_PAGESIZE * NUMBER_OF_PAGES] __attribute__ (( aligned(SPM_PAGESIZE) )) PROGMEM = {
@@ -71,6 +71,11 @@ void loop()
   Serial.println();
   Serial.println(F("|------------------------------------------------|"));
   Serial.println(F("| Welcome to the Optiboot flash writer example!  |"));
+#ifdef USE_NVMCTRL
+  Serial.println(F("| Running on mega0/xTiny with NVMCTRL support.   |"));
+#else
+  Serial.println(F("| Running on traditional AVR with SPM support.   |"));
+#endif
   Serial.print(F("| Each flash page is "));
   Serial.print(SPM_PAGESIZE);
   Serial.println(F(" bytes long.             |"));
@@ -155,6 +160,7 @@ void loop()
       Serial.print(F("\nContent of page "));
       Serial.print(pageNumber);
       Serial.println(F(":"));
+      ramBuffer[SPM_PAGESIZE] = 0;  // null terminate!
       Serial.println((char*)ramBuffer);
     }