mcu/nrf5340: Enable NSC region

Enable NSC region if sgstubs section is not empty Signed-off-by: Jerzy Kasenberg <[email protected]>
apache · Oct 31, 2024 · 010af90 · 010af90
1 parent f08817b
commit 010af90
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Showing 2 changed files with 36 additions and 1 deletion.
diff --git a/hw/mcu/nordic/nrf5340/nrf5340.ld b/hw/mcu/nordic/nrf5340/nrf5340.ld
@@ -46,6 +46,8 @@ OUTPUT_FORMAT ("elf32-littlearm", "elf32-bigarm", "elf32-littlearm")
  */
 ENTRY(Reset_Handler)
 
+NSC_REGION_SIZE = 0x200;
+
 SECTIONS
 {
     .imghdr (NOLOAD):
@@ -107,7 +109,6 @@ INCLUDE "link_tables.ld.h"
         . = ALIGN(4);
     } > FLASH
 
-
     .net_core_img :
     {
         PROVIDE(net_core_img_start = .);
@@ -127,6 +128,15 @@ INCLUDE "link_tables.ld.h"
         *(.ARM.exidx* .gnu.linkonce.armexidx.*)
         . = ALIGN(4);
     } > FLASH
+
+    .gnu.sgstubs :
+    {
+        FILL(0xffff);
+        . = (ALIGN(16384) >= . + NSC_REGION_SIZE) ? (ALIGN(16384) - NSC_REGION_SIZE) : (ALIGN(16384) - NSC_REGION_SIZE + 16384);
+        _start_sg = .;
+    } > FLASH
+    PROVIDE(_end_sg = .);
+
     __exidx_end = .;
 
     __etext = .;

diff --git a/hw/mcu/nordic/nrf5340/src/hal_system_start.c b/hw/mcu/nordic/nrf5340/src/hal_system_start.c
@@ -66,6 +66,27 @@ static const unsigned int periph_gpios[] = { UNMANGLE_MYNEWT_VAL(MYNEWT_VAL(MCU_
 #endif
 
 extern uint8_t __StackTop[];
+extern uint8_t _start_sg[];
+extern uint8_t _end_sg[];
+
+
+static void
+init_nsc(void)
+{
+    int region = (uintptr_t)_start_sg / 0x4000;
+    uintptr_t region_start = region * 0x4000;
+    uintptr_t region_limit = region_start + 0x4000;
+    int nsc_region_size = 32;
+    int m = 1;
+    /* Calculate NSC region size by checking _start_sg offset in last 16K region */
+    while ((uintptr_t)_start_sg < region_limit - nsc_region_size) {
+        m++;
+        nsc_region_size <<= 1;
+    }
+    assert(m <= 8);
+    NRF_SPU_S->FLASHNSC[0].REGION = region;
+    NRF_SPU_S->FLASHNSC[0].SIZE = m;
+}
 
 void
 hal_system_start(void *img_start)
@@ -106,6 +127,10 @@ hal_system_start(void *img_start)
         NRF_SPU->FLASHREGION[i].PERM &= ~SPU_FLASHREGION_PERM_SECATTR_Msk;
     }
 
+    if ((uint32_t)_start_sg < (uint32_t)_end_sg) {
+        init_nsc();
+    }
+
     /* Mark RAM as non-secure */
     for (i = 0; i < 64; ++i) {
         NRF_SPU->RAMREGION[i].PERM &= ~SPU_FLASHREGION_PERM_SECATTR_Msk;