flash/nor/bluenrg-x: clarify target algo stack usage

While on it rename misleading write_algorithm_sp to write_algorithm_stack
and change messages referring 'stack pointer' instead of stack.

No functional change.

Change-Id: Ibb9897d3f01734812ed0f8bc8cd43b935a573f8a
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: https://review.openocd.org/c/openocd/+/7132
Tested-by: jenkins
Reviewed-by: Salvatore Giorgio Pecorino <salvatore-giorgio.pecorino@st.com>
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

diff --git a/src/flash/nor/bluenrg-x.c b/src/flash/nor/bluenrg-x.c
index d4fb5e972b87df44b3ac62d4d23a05cb905f503d..ec5cae76e7ebf13794695b039b7f3c90c126a6d3 100644 (file)
--- a/src/flash/nor/bluenrg-x.c
+++ b/src/flash/nor/bluenrg-x.c
@@ -236,7 +236,7 @@ static int bluenrgx_write(struct flash_bank *bank, const uint8_t *buffer,
        struct target *target = bank->target;
        uint32_t buffer_size = 16384 + 8;
        struct working_area *write_algorithm;
-       struct working_area *write_algorithm_sp;
+       struct working_area *write_algorithm_stack;
        struct working_area *source;
        uint32_t address = bank->base + offset;
        struct reg_param reg_params[5];
@@ -285,10 +285,10 @@ static int bluenrgx_write(struct flash_bank *bank, const uint8_t *buffer,
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }
 
-       /* Stack pointer area */
+       /* Stack area */
        if (target_alloc_working_area(target, 128,
-                                         &write_algorithm_sp) != ERROR_OK) {
-               LOG_DEBUG("no working area for write code stack pointer");
+                                         &write_algorithm_stack) != ERROR_OK) {
+               LOG_DEBUG("no working area for target algorithm stack");
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }
 
@@ -300,8 +300,19 @@ static int bluenrgx_write(struct flash_bank *bank, const uint8_t *buffer,
        init_reg_param(&reg_params[2], "r2", 32, PARAM_OUT);
        init_reg_param(&reg_params[3], "r3", 32, PARAM_OUT);
        init_reg_param(&reg_params[4], "sp", 32, PARAM_OUT);
-       /* Put the parameter at the first available stack location */
-       init_mem_param(&mem_params[0], write_algorithm_sp->address + 80, 32, PARAM_OUT);
+       /* Put the 4th parameter at the location in the stack frame of target write() function.
+        * See contrib/loaders/flash/bluenrg-x/bluenrg-x_write.lst
+        * 34 ldr     r6, [sp, #80]
+        *                     ^^^ offset
+        */
+       init_mem_param(&mem_params[0], write_algorithm_stack->address + 80, 32, PARAM_OUT);
+       /* Stack for target write algorithm - target write() function has
+        * __attribute__((naked)) so it does not setup the new stack frame.
+        * Therefore the stack frame uses the area from SP upwards!
+        * Interrupts are disabled and no subroutines are called from write()
+        * so no need to allocate stack below SP.
+        * TODO: remove __attribute__((naked)) and use similar parameter passing as stm32l4x */
+       buf_set_u32(reg_params[4].value, 0, 32, write_algorithm_stack->address);
 
        /* FIFO start address (first two words used for write and read pointers) */
        buf_set_u32(reg_params[0].value, 0, 32, source->address);
@@ -311,14 +322,12 @@ static int bluenrgx_write(struct flash_bank *bank, const uint8_t *buffer,
        buf_set_u32(reg_params[2].value, 0, 32, address);
        /* Number of bytes */
        buf_set_u32(reg_params[3].value, 0, 32, count);
-       /* Stack pointer for program working area */
-       buf_set_u32(reg_params[4].value, 0, 32, write_algorithm_sp->address);
        /* Flash register base address */
        buf_set_u32(mem_params[0].value, 0, 32, bluenrgx_info->flash_ptr->flash_regs_base);
 
        LOG_DEBUG("source->address = " TARGET_ADDR_FMT, source->address);
        LOG_DEBUG("source->address+ source->size = " TARGET_ADDR_FMT, source->address+source->size);
-       LOG_DEBUG("write_algorithm_sp->address = " TARGET_ADDR_FMT, write_algorithm_sp->address);
+       LOG_DEBUG("write_algorithm_stack->address = " TARGET_ADDR_FMT, write_algorithm_stack->address);
        LOG_DEBUG("address = %08" PRIx32, address);
        LOG_DEBUG("count = %08" PRIx32, count);
 
@@ -357,7 +366,7 @@ static int bluenrgx_write(struct flash_bank *bank, const uint8_t *buffer,
        }
        target_free_working_area(target, source);
        target_free_working_area(target, write_algorithm);
-       target_free_working_area(target, write_algorithm_sp);
+       target_free_working_area(target, write_algorithm_stack);
 
        destroy_reg_param(&reg_params[0]);
        destroy_reg_param(&reg_params[1]);