flash/nor/rp2xxx: fix flash operation after halt in RISC-V bootsel

Calling ROM API set_bootrom_stack() function allows ROM API functionality
after OpenOCD halt or reset halt in RISC-V bootloder (emulated ARM code)

Change-Id: I3b255738d61876e876a94207804d9cbe1a7593c2
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Signed-off-by: Luke Wren <luke@raspberrypi.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8729
Tested-by: jenkins

diff --git a/src/flash/nor/rp2xxx.c b/src/flash/nor/rp2xxx.c
index fce501703d2b455f9fa36ffd35b1f1cc1b8ff9a3..280f077c1c69dcff83da503ca3d3d8f10f7d926c 100644 (file)
--- a/src/flash/nor/rp2xxx.c
+++ b/src/flash/nor/rp2xxx.c
@@ -26,6 +26,7 @@
 #define FUNC_FLASH_FLUSH_CACHE         MAKE_TAG('F', 'C')
 #define FUNC_FLASH_ENTER_CMD_XIP       MAKE_TAG('C', 'X')
 #define FUNC_BOOTROM_STATE_RESET       MAKE_TAG('S', 'R')
+#define FUNC_BOOTROM_SET_STACK         MAKE_TAG('S', 'S')
 #define FUNC_FLASH_RESET_ADDRESS_TRANS MAKE_TAG('R', 'A')
 
 /* ROM table flags for RP2350 A1 ROM onwards */
@@ -201,6 +202,7 @@ struct rp2xxx_flash_bank {
        uint16_t jump_flash_reset_address_trans;
        uint16_t jump_enter_cmd_xip;
        uint16_t jump_bootrom_reset_state;
+       uint16_t jump_bootrom_set_varm_stack;
 
        char dev_name[20];
        bool size_override;
@@ -445,6 +447,15 @@ static int rp2xxx_populate_rom_pointer_cache(struct target *target, struct rp2xx
                LOG_WARNING("Function FUNC_BOOTROM_STATE_RESET not found in RP2xxx ROM. (probably an RP2350 A0)");
        }
 
+       if (!is_arm(target_to_arm(target))) {
+               err = rp2xxx_lookup_rom_symbol(target, FUNC_BOOTROM_SET_STACK, symtype_func,
+                                                                          &priv->jump_bootrom_set_varm_stack);
+               if (err != ERROR_OK) {
+                       priv->jump_bootrom_set_varm_stack = 0;
+                       LOG_WARNING("Function FUNC_BOOTROM_SET_STACK not found in RP2xxx ROM. (probably an RP2350 A0)");
+               }
+       }
+
        err = rp2xxx_lookup_rom_symbol(target, FUNC_FLASH_RESET_ADDRESS_TRANS,
                                                                   symtype_func, &priv->jump_flash_reset_address_trans);
        if (err != ERROR_OK) {
@@ -720,6 +731,9 @@ static int setup_for_raw_flash_cmd(struct target *target, struct rp2xxx_flash_ba
                if (!priv->jump_bootrom_reset_state) {
                        LOG_WARNING("RP2350 flash: no bootrom_reset_method\n");
                } else {
+                       /* This is mainly required to clear varmulet_enclosing_cpu pointers on RISC-V, in case
+                          an Arm -> RISC-V call has been interrupted (these pointers are used to handle
+                          reentrant calls to the ROM emulator) */
                        LOG_DEBUG("Clearing core 0 ROM state");
                        err = rp2xxx_call_rom_func(target, priv, priv->jump_bootrom_reset_state,
                                                                           reset_args, ARRAY_SIZE(reset_args));
@@ -728,6 +742,39 @@ static int setup_for_raw_flash_cmd(struct target *target, struct rp2xxx_flash_ba
                                return err;
                        }
                }
+               if (!is_arm(target_to_arm(target)) && priv->jump_bootrom_set_varm_stack) {
+                       /* Pass {0, 0} to set_varmulet_user_stack() to enable automatic emulation of Arm APIs
+                          using the ROM's default stacks. Usually the bootrom does this before exiting to user
+                          code, but it needs to be done manually when the USB bootloader has been interrupted. */
+                       LOG_DEBUG("Enabling default Arm emulator stacks for RISC-V ROM calls\n");
+                       struct working_area *set_stack_mem_args;
+                       err = target_alloc_working_area(target, 2 * sizeof(uint32_t), &set_stack_mem_args);
+                       if (err != ERROR_OK) {
+                               LOG_ERROR("Failed to allocate memory for arguments to set_varmulet_user_stack()");
+                               return err;
+                       }
+
+                       err = target_write_u32(target, set_stack_mem_args->address, 0);
+                       if (err == ERROR_OK)
+                               err = target_write_u32(target, set_stack_mem_args->address + 4, 0);
+
+                       if (err != ERROR_OK) {
+                               LOG_ERROR("Failed to initialise memory arguments for set_varmulet_user_stack()");
+                               target_free_working_area(target, set_stack_mem_args);
+                               return err;
+                       }
+
+                       uint32_t set_stack_register_args[1] = {
+                               set_stack_mem_args->address
+                       };
+                       err = rp2xxx_call_rom_func(target, priv, priv->jump_bootrom_set_varm_stack,
+                                                                          set_stack_register_args, ARRAY_SIZE(set_stack_register_args));
+                       target_free_working_area(target, set_stack_mem_args);
+                       if (err != ERROR_OK) {
+                               LOG_ERROR("Failed to initialise Arm emulation stacks for RISC-V: 0x%08" PRIx32, err);
+                               return err;
+                       }
+               }
        }
 
        LOG_DEBUG("Connecting flash IOs and issuing XIP exit sequence to flash");