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openocd/contrib/loaders/reset/espressif/esp32/esp32_cpu_reset_handler.S
Erhan Kurubas 7e8ea96345 loaders/reset/espressif: replace the GPL-2.0-or-later license tag
Replace the FSF boilerplate with the SPDX tag.

Signed-off-by: Erhan Kurubas <erhan.kurubas@espressif.com>
Change-Id: Iddccae2bd8906a3587a2aa2684124356a340fc74
Reviewed-on: https://review.openocd.org/c/openocd/+/7105
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
2022-08-15 13:23:28 +00:00

135 lines
4.4 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-or-later */
/***************************************************************************
* Reset stub used by esp32 target *
* Copyright (C) 2017 Espressif Systems Ltd. *
***************************************************************************/
#define RTC_CNTL_RESET_STATE_REG 0x3ff48034
#define RTC_CNTL_RESET_STATE_DEF 0x3000
#define RTC_CNTL_CLK_CONF_REG 0x3ff48070
#define RTC_CNTL_CLK_CONF_DEF 0x2210
#define RTC_CNTL_STORE4_REG 0x3ff480b0
#define RTC_CNTL_STORE5_REG 0x3ff480b4
#define WDT_WKEY_VALUE 0x50D83AA1
#define TIMG0_WDTWPROTECT_REG 0x3ff5f064
#define TIMG0_WDTCONFIG0_REG 0x3ff5f048
#define TIMG1_WDTWPROTECT_REG 0x3FF60064
#define TIMG1_WDTCONFIG0_REG 0x3ff60048
#define RTC_CNTL_WDTCONFIG0_REG 0x3ff4808c
#define RTC_CNTL_WDTWPROTECT_REG 0x3ff480a4
#define JTAG_ENABLE_REG 0x3ff5a1fc
#define RTC_CNTL_OPTIONS0_REG 0x3ff48000
#define RTC_CNTL_OPTIONS0_DEF 0x1c492000
#define RTC_CNTL_SW_SYS_RST 0x80000000
#define DPORT_APPCPU_CTRL_A_REG 0x3ff0002c
#define DPORT_APPCPU_RST_EN 0x1
#define DPORT_APPCPU_CTRL_B_REG 0x3ff00030
#define DPORT_APPCPU_CLKGATE_EN 0x1
#define DPORT_APPCPU_CTRL_C_REG 0x3ff00034
#define DPORT_APPCPU_CTRL_D_REG 0x3ff00038
/* This stub is copied to RTC_SLOW_MEM by OpenOCD, and the CPU starts executing
* it instead of the ROM code (0x40000400). This stub disables watchdogs and
* goes into a loop.
* OpenOCD will then halt the target and perform CPU reset using OCD.
*/
/* Has to be at offset 0. This is the entry point of the CPU, once
* RTC_CNTL_PROCPU_STAT_VECTOR_SEL is cleared.
* CPU will come here after the system reset, triggered by RTC_CNTL_SW_SYS_RST.
*/
.global cpu_at_start_handler
.type cpu_at_start_handler,@function
.align 4
cpu_at_start_handler:
j start
/* Has to be at offset 4. Once the stub code has been uploaded into RTC Slow
* memory, OpenOCD will set the PC to this address, and resume execution.
* The stub will then jump to 'reset' label and perform the reset.
*/
.global cpu_reset_handler
.type cpu_reset_handler,@function
.align 4
cpu_reset_handler:
j reset
.align 4
.literal_position
.align 4
reset:
/* Use a5 as a zero register */
xor a5, a5, a5
/* Select static reset vector 0 (XCHAL_RESET_VECTOR0_VADDR, 0x50000000) */
movi a4, RTC_CNTL_RESET_STATE_REG
s32i a5, a4, 0
/* Set some clock-related RTC registers to the default values */
movi a4, RTC_CNTL_STORE4_REG
s32i a5, a4, 0
movi a4, RTC_CNTL_STORE5_REG
s32i a5, a4, 0
movi a4, RTC_CNTL_CLK_CONF_REG
movi a3, RTC_CNTL_CLK_CONF_DEF
s32i a3, a4, 0
/* Reset the digital part of the chip (RTC controller doesn't get reset) */
movi a3, (RTC_CNTL_OPTIONS0_DEF | RTC_CNTL_SW_SYS_RST)
movi a4, RTC_CNTL_OPTIONS0_REG
s32i a3, a4, 0
/* Doesn't reach beyond this instruction */
.align 4
start:
/* If running on the APP CPU, skip directly to the parking loop */
rsr.prid a6
extui a6, a6, 1, 1
bnez a6, parking_loop
/* Use a5 as a zero register */
xor a5, a5, a5
/* Disable the watchdogs */
movi a3, WDT_WKEY_VALUE
movi a4, RTC_CNTL_WDTWPROTECT_REG
s32i.n a3, a4, 0
movi a4, TIMG0_WDTWPROTECT_REG
s32i.n a3, a4, 0
movi a4, TIMG1_WDTWPROTECT_REG
s32i.n a3, a4, 0
movi a4, RTC_CNTL_WDTCONFIG0_REG
s32i.n a5, a4, 0
movi a4, TIMG0_WDTCONFIG0_REG
s32i.n a5, a4, 0
movi a4, TIMG1_WDTCONFIG0_REG
s32i.n a5, a4, 0
/* Enable JTAG (needed since rev. 3) */
movi a4, JTAG_ENABLE_REG
s32i.n a5, a4, 0
/* Clear APP_CPU boot address */
movi a4, DPORT_APPCPU_CTRL_D_REG
s32i.n a5, a4, 0
/* Clear APP_CPU clock gating */
movi a4, DPORT_APPCPU_CTRL_B_REG
movi a3, DPORT_APPCPU_CLKGATE_EN
s32i.n a3, a4, 0
/* Set and clear APP_CPU reset */
movi a4, DPORT_APPCPU_CTRL_A_REG
movi a3, DPORT_APPCPU_RST_EN
s32i.n a3, a4, 0
s32i.n a5, a4, 0
/* Restore the reset vector to ROM */
movi a4, RTC_CNTL_RESET_STATE_REG
movi a3, RTC_CNTL_RESET_STATE_DEF
s32i.n a3, a4, 0
parking_loop:
/* PRO and APP CPU will be in this loop, until OpenOCD
* finds the JTAG taps and puts the CPUs into debug mode.
*/
waiti 0
j parking_loop