| /* |
| * Copyright (c) 2018 Piotr Mienkowski |
| * |
| * SPDX-License-Identifier: Apache-2.0 |
| */ |
| |
| /** @file |
| * @brief Serial Wire Output (SWO) backend implementation. |
| * |
| * SWO/SWV has been developed by ARM. The following code works only on ARM |
| * architecture. |
| * |
| * An SWO viewer program will typically set-up the SWO port including its |
| * frequency when connected to the debug probe. Such configuration can persist |
| * only until the MCU reset. The SWO backend initialization function will |
| * re-configure the SWO port upon boot and set the frequency as specified by |
| * the LOG_BACKEND_SWO_FREQ_HZ Kconfig option. To ensure flawless operation |
| * this frequency should much the one set by the SWO viewer program. |
| * |
| * The initialization code assumes that SWO core frequency is equal to HCLK |
| * as defined by the clock-frequency property in the CPU node. This may require |
| * additional, vendor specific configuration. |
| */ |
| |
| #include <logging/log_backend.h> |
| #include <logging/log_core.h> |
| #include <logging/log_msg.h> |
| #include <logging/log_output.h> |
| #include "log_backend_std.h" |
| #include <soc.h> |
| |
| /** The stimulus port from which SWO data is received and displayed */ |
| #define ITM_PORT_LOGGER 0 |
| |
| /* Set TPIU prescaler for the current debug trace clock frequency. */ |
| #if CONFIG_LOG_BACKEND_SWO_FREQ_HZ == 0 |
| #define SWO_FREQ_DIV 1 |
| #else |
| #if DT_NODE_HAS_PROP(DT_PATH(cpus, cpu_0), clock_frequency) |
| #define CPU_FREQ DT_PROP(DT_PATH(cpus, cpu_0), clock_frequency) |
| #else |
| #error "Missing DT 'clock-frequency' property on cpu@0 node" |
| #endif |
| #define SWO_FREQ (CPU_FREQ + (CONFIG_LOG_BACKEND_SWO_FREQ_HZ / 2)) |
| #define SWO_FREQ_DIV (SWO_FREQ / CONFIG_LOG_BACKEND_SWO_FREQ_HZ) |
| #if SWO_FREQ_DIV > 0xFFFF |
| #error CONFIG_LOG_BACKEND_SWO_FREQ_HZ is too low. SWO clock divider is 16-bit. \ |
| Minimum supported SWO clock frequency is \ |
| [CPU Clock Frequency]/2^16. |
| #endif |
| #endif |
| |
| static uint8_t buf[1]; |
| |
| static int char_out(uint8_t *data, size_t length, void *ctx) |
| { |
| ARG_UNUSED(ctx); |
| |
| for (size_t i = 0; i < length; i++) { |
| ITM_SendChar(data[i]); |
| } |
| |
| return length; |
| } |
| |
| LOG_OUTPUT_DEFINE(log_output_swo, char_out, buf, sizeof(buf)); |
| |
| static void log_backend_swo_put(const struct log_backend *const backend, |
| struct log_msg *msg) |
| { |
| uint32_t flag = IS_ENABLED(CONFIG_LOG_BACKEND_SWO_SYST_ENABLE) ? |
| LOG_OUTPUT_FLAG_FORMAT_SYST : 0; |
| |
| log_backend_std_put(&log_output_swo, flag, msg); |
| } |
| |
| static void log_backend_swo_init(void) |
| { |
| /* Enable DWT and ITM units */ |
| CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk; |
| /* Enable access to ITM registers */ |
| ITM->LAR = 0xC5ACCE55; |
| /* Disable stimulus ports ITM_STIM0-ITM_STIM31 */ |
| ITM->TER = 0x0; |
| /* Disable ITM */ |
| ITM->TCR = 0x0; |
| /* Select NRZ (UART) encoding protocol */ |
| TPI->SPPR = 2; |
| /* Set SWO baud rate prescaler value: SWO_clk = ref_clock/(ACPR + 1) */ |
| TPI->ACPR = SWO_FREQ_DIV - 1; |
| /* Enable unprivileged access to ITM stimulus ports */ |
| ITM->TPR = 0x0; |
| /* Configure Debug Watchpoint and Trace */ |
| DWT->CTRL = 0x400003FE; |
| /* Configure Formatter and Flush Control Register */ |
| TPI->FFCR = 0x00000100; |
| /* Enable ITM, set TraceBusID=1, no local timestamp generation */ |
| ITM->TCR = 0x0001000D; |
| /* Enable stimulus port used by the logger */ |
| ITM->TER = 1 << ITM_PORT_LOGGER; |
| } |
| |
| static void log_backend_swo_panic(struct log_backend const *const backend) |
| { |
| } |
| |
| static void dropped(const struct log_backend *const backend, uint32_t cnt) |
| { |
| ARG_UNUSED(backend); |
| |
| log_backend_std_dropped(&log_output_swo, cnt); |
| } |
| |
| static void log_backend_swo_sync_string(const struct log_backend *const backend, |
| struct log_msg_ids src_level, uint32_t timestamp, |
| const char *fmt, va_list ap) |
| { |
| uint32_t flag = IS_ENABLED(CONFIG_LOG_BACKEND_SWO_SYST_ENABLE) ? |
| LOG_OUTPUT_FLAG_FORMAT_SYST : 0; |
| |
| log_backend_std_sync_string(&log_output_swo, flag, src_level, |
| timestamp, fmt, ap); |
| } |
| |
| static void log_backend_swo_sync_hexdump( |
| const struct log_backend *const backend, |
| struct log_msg_ids src_level, uint32_t timestamp, |
| const char *metadata, const uint8_t *data, uint32_t length) |
| { |
| uint32_t flag = IS_ENABLED(CONFIG_LOG_BACKEND_SWO_SYST_ENABLE) ? |
| LOG_OUTPUT_FLAG_FORMAT_SYST : 0; |
| |
| log_backend_std_sync_hexdump(&log_output_swo, flag, src_level, |
| timestamp, metadata, data, length); |
| } |
| |
| const struct log_backend_api log_backend_swo_api = { |
| .put = IS_ENABLED(CONFIG_LOG_IMMEDIATE) ? NULL : log_backend_swo_put, |
| .put_sync_string = IS_ENABLED(CONFIG_LOG_IMMEDIATE) ? |
| log_backend_swo_sync_string : NULL, |
| .put_sync_hexdump = IS_ENABLED(CONFIG_LOG_IMMEDIATE) ? |
| log_backend_swo_sync_hexdump : NULL, |
| .panic = log_backend_swo_panic, |
| .init = log_backend_swo_init, |
| .dropped = IS_ENABLED(CONFIG_LOG_IMMEDIATE) ? NULL : dropped, |
| }; |
| |
| LOG_BACKEND_DEFINE(log_backend_swo, log_backend_swo_api, true); |