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[ISSUE-36]: UHCI / UDMA vs. UART FIFO feed performance comparison.
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8 files changed

Lines changed: 320 additions & 3 deletions

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‎configure.ac‎

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@@ -19,6 +19,7 @@ AC_CONFIG_SUBDIRS([examples/0blink])
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AC_CONFIG_SUBDIRS([examples/0hello])
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AC_CONFIG_SUBDIRS([examples/0ledctrl])
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AC_CONFIG_SUBDIRS([examples/0uart])
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AC_CONFIG_SUBDIRS([examples/0udma])
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AC_CONFIG_SUBDIRS([examples/1rmtblink])
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AC_CONFIG_SUBDIRS([examples/1rmtdht])
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AC_CONFIG_SUBDIRS([examples/1rmtmorse])
@@ -38,6 +39,7 @@ AC_CONFIG_FILES([
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examples/0hello/Makefile
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examples/0ledctrl/Makefile
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examples/0uart/Makefile
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examples/0udma/Makefile
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examples/1rmtblink/Makefile
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examples/1rmtdht/Makefile
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examples/1rmtmorse/Makefile

‎examples/0udma/Makefile.am‎

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include $(top_srcdir)/scripts/elf2bin.mk
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include $(top_srcdir)/ld/flags.mk
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noinst_HEADERS = defines.h
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AM_CFLAGS = -std=c11 -flto
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if WITH_BINARIES
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AM_LDFLAGS += \
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-T $(top_srcdir)/ld/esp32.rom.ld \
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-T $(top_srcdir)/ld/esp32.rom.libgcc.ld \
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-T $(top_srcdir)/ld/esp32.rom.newlib-data.ld \
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-T $(top_srcdir)/ld/esp32.rom.newlib-locale.ld \
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-T $(top_srcdir)/ld/esp32.rom.newlib-nano.ld \
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-T $(top_srcdir)/ld/esp32.rom.newlib-time.ld \
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-T $(top_srcdir)/ld/esp32.rom.redefined.ld \
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-T $(top_srcdir)/ld/esp32.rom.syscalls.ld
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else
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AM_LDFLAGS += \
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-T $(top_srcdir)/ld/esp32.rom.ld \
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-T $(top_srcdir)/ld/esp32.rom.libgcc.ld \
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-T $(top_srcdir)/ld/esp32.rom.redefined.ld \
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-T $(top_srcdir)/ld/esp32.rom.syscalls.ld
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endif
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AM_CPPFLAGS = -I$(top_srcdir)/src
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LDADD = $(top_builddir)/src/libesp32basic.a
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bin_PROGRAMS = \
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uarttx.elf
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if WITH_BINARIES
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CLEANFILES = \
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uarttx.bin
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endif
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BUILT_SOURCES = $(CLEANFILES)

‎examples/0udma/README.md‎

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### UART TX transfer performance comparison
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In this example we compare UART FIFO feed speed to UDMA transfer.
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The application performs repeatedly the following phases:
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* 1st phase - do UART FIFO feed;
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* 2nd phase - print UART FIFO feed duration;
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* 3rd phase - initiate UDMA TX transfer;
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* 4th phase - print UDMA transfer duration.
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Between phases 3 and 4 we catch UHCI TX complete interrupt.
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After the last phase the length of the transferred message is increased (from 100 bytes up to 1000 bytes).
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#### Hardware components
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You have to access the `UART0` channel of the ESP32 somehow.
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Probably, you have flashed the binary to ESP32 over USB line
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and at the ESP32 end there is an *UART_over_USB* module (e.g., `cp210x converter`).
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So if you have an USB cable connecting the ESP32 module to your PC, that is fine.
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#### Software requirements
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On your PC, choose your favorite serial terminal tool.
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My choice is *miniterm*:
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```sh
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python -m serial.tools.miniterm --filter=direct /dev/ttyUSB0 115200 --rts 0
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```

‎examples/0udma/defines.h‎

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/*
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* Copyright 2025 SZIGETI János
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*
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* This file is part of Bilis ESP32 Basic, which is released under GNU General Public License.version 3.
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* See LICENSE or <https://www.gnu.org/licenses/> for full license details.
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*/
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#ifndef DEFINES_H
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#define DEFINES_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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// TIMINGS
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// const -- do not change this value
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#define APB_FREQ_HZ 80000000U // 80 MHz
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// variables
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#define TIM0_0_DIVISOR 2U
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#define START_APP_CPU 0U
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#define SCHEDULE_FREQ_HZ 1000U // 10KHz
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// derived invariants
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#define CLK_FREQ_HZ (APB_FREQ_HZ / TIM0_0_DIVISOR) // 40 MHz
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#define TICKS_PER_MS (CLK_FREQ_HZ / 1000U) // 40000
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#define TICKS_PER_US (CLK_FREQ_HZ / 1000000U) // 40
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#define MS2TICKS(X) ((X) * TICKS_PER_MS)
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#define HZ2APBTICKS(X) (APB_FREQ_HZ / (X))
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#ifdef __cplusplus
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}
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#endif
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#endif /* DEFINES_H */
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‎examples/0udma/uarttx.c‎

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/*
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* Copyright 2024 SZIGETI János
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*
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* This file is part of Bilis ESP32 Basic, which is released under GNU General Public License.version 3.
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* See LICENSE or <https://www.gnu.org/licenses/> for full license details.
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*/
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#include <stdbool.h>
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#include <stdlib.h>
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#include <inttypes.h>
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#include "esp_attr.h"
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#include "main.h"
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#include "defines.h"
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#include "dport.h"
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#include "romfunctions.h"
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#include "timg.h"
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#include "uart.h"
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#include "utils/uartutils.h"
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// =================== Hard constants =================
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// #1: Timings
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#define UART_FREQ_HZ 115200U
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#define CYCLE_PERIOD_MS 1000U
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// #2: Sizes
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#define TEST_PATTERN_LENGTH 1000U
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#define MSG_INC_STEP 100U
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// #3: Channels
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#define UHCI_INT_CH 23U
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// ============= Local types ===============
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typedef struct {
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uint32_t u12Size : 12;
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uint32_t u12Length : 12;
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uint32_t rsvd24: 6;
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uint32_t bEof : 1;
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uint32_t bOwner : 1;
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void *pcData;
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void *psNext;
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} UdmaDescriptor;
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// ================ Local function declarations =================
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static void _pattern_init();
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static void _uart_init();
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static void _uart_cycle(uint64_t u64tckNow);
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static void _uhci_isr(void *pvParam);
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// =================== Global constants ================
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const bool gbStartAppCpu = START_APP_CPU;
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const uint16_t gu16Tim00Divisor = TIM0_0_DIVISOR;
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const uint64_t gu64tckSchedulePeriod = (CLK_FREQ_HZ / SCHEDULE_FREQ_HZ);
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// =================== Local constants ================
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static const TimerId gsTimer = {.eTimg = TIMG_0, .eTimer = TIMER0};
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static const EUartController geUart = UART_CTL0;
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static const EUdmaController geUdma = UDMA_CTL0;
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static const ECpu eIntCpu = CPU_PRO;
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static UART_Type *gpsUART = geUart == UART_CTL0? &gsUART0 : geUart == UART_CTL1 ? &gsUART1 : &gsUART2;
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static UHCI_Type *gpsUHCI = geUdma == UDMA_CTL0? &gsUHCI0 : &gsUHCI1;
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// ==================== Local Data ================
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static uint8_t gu8Phase = 0;
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static uint64_t gu64TckUartTxStart;
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static uint64_t gu64TckUartTxStop;
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static uint64_t gu64TckUdmaTxStart;
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static uint64_t gu64TckUdmaTxStop;
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static volatile uint64_t gu64TckUdmaTxDone;
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static volatile uint64_t gu64TckUdmaTxTotalEof;
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static char gacTestPattern[TEST_PATTERN_LENGTH];
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static UdmaDescriptor gsUdmaDesc;
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// Implementation
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// ==================== Local Functions ================
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static void _pattern_init() {
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for (int i = 0; i < TEST_PATTERN_LENGTH; ++i) {
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gacTestPattern[i] = '0' + (i % 10);
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}
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}
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static void _uart_init() {
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#define UART_CLKDIV_INT HZ2APBTICKS(UART_FREQ_HZ)
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#define UART_CLKDIV_REM (APB_FREQ_HZ - (UART_CLKDIV_INT * UART_FREQ_HZ))
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#define UART_CLKDIV_FRAG ((16U * UART_CLKDIV_REM) / UART_FREQ_HZ)
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// version A)
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gpsUART->CLKDIV.u20ClkDiv = UART_CLKDIV_INT;
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gpsUART->CLKDIV.u4ClkDivFrag = UART_CLKDIV_FRAG;
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// version B)
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// gpsUART->CLKDIV.raw = UART_CLKDIV_INT | (UART_CLKDIV_FRAG << 20); // this line results in shorter binary file
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#undef UART_CLKDIV_FRAG
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#undef UART_CLKDIV_REM
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#undef UART_CLKDIV_INT
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uart_init_udma(geUart, geUdma);
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gpsUHCI->INT_ENA = (1 << UHCI_INT_OUTTOTALEOF) | (1 << UHCI_INT_OUTDONE);
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// register ISR and enable it
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RegAddr prDportIntMap = (eIntCpu == CPU_PRO ? &dport_regs()->PRO_UHCI0_INTR_MAP : &dport_regs()->APP_UHCI0_INTR_MAP);
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prDportIntMap += geUdma;
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*prDportIntMap = UHCI_INT_CH;
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_xtos_set_interrupt_handler_arg(UHCI_INT_CH, _uhci_isr, 0);
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ets_isr_unmask(1 << UHCI_INT_CH);
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}
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static void _uart_cycle(uint64_t u64tckNow) {
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static uint64_t u64tckNext = 0;
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static uint32_t u32MsgLen = MSG_INC_STEP;
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if (u64tckNext <= u64tckNow) {
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switch (gu8Phase) {
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case 0:
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uart_printf(gpsUART, "Sending message of %u bytes\r\n", u32MsgLen);
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break;
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case 1:
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gu64TckUartTxStart = timg_ticks(gsTimer);
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for (int i = 0; i < u32MsgLen; ++i) {
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gpsUART->FIFO = gacTestPattern[i];
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}
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gu64TckUartTxStop = timg_ticks(gsTimer);
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break;
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case 2:
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uart_printf(gpsUART, "\r\nUART TX duration: %u ns\r\n", (uint32_t)((gu64TckUartTxStop - gu64TckUartTxStart) / TICKS_PER_US));
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break;
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case 3:
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gsUdmaDesc = (UdmaDescriptor) {
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.bEof = true,
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.bOwner = true,
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.pcData = gacTestPattern,
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.psNext = NULL,
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.u12Length = u32MsgLen,
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.u12Size = TEST_PATTERN_LENGTH
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};
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gpsUHCI->INT_CLR = -1;
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gu64TckUdmaTxStart = timg_ticks(gsTimer);
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gpsUHCI->OUT_LINK = (((uint32_t)&gsUdmaDesc)&0xfffff) | (1 << 29);
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gu64TckUdmaTxStop = timg_ticks(gsTimer);
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break;
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case 4:
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uart_printf(gpsUART, "\r\nUDMA TX duration: %u (send), %u (done), %u (eof) ns)\r\n",
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(uint32_t)((gu64TckUdmaTxStop - gu64TckUdmaTxStart) / TICKS_PER_US),
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(uint32_t)((gu64TckUdmaTxDone - gu64TckUdmaTxStart) / TICKS_PER_US),
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(uint32_t)((gu64TckUdmaTxTotalEof - gu64TckUdmaTxStart) / TICKS_PER_US));
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break;
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}
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++gu8Phase;
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if (gu8Phase == 5) {
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gu8Phase = 0;
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u32MsgLen+=MSG_INC_STEP;
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if (TEST_PATTERN_LENGTH < u32MsgLen) {
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u32MsgLen = MSG_INC_STEP;
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}
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}
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u64tckNext += MS2TICKS(CYCLE_PERIOD_MS);
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}
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}
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IRAM_ATTR static void _uhci_isr(void *pvParam) {
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bool bOutDoneEvent = gpsUHCI->INT_ST & (1 << UHCI_INT_OUTDONE);
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bool bOutTotalEofEvent = gpsUHCI->INT_ST & (1 << UHCI_INT_OUTTOTALEOF);
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if (bOutDoneEvent) {
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gu64TckUdmaTxDone = timg_ticks(gsTimer);
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gpsUHCI->INT_CLR = 1 << UHCI_INT_OUTDONE;
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}
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if (bOutTotalEofEvent) {
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gu64TckUdmaTxTotalEof = timg_ticks(gsTimer);
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gpsUHCI->INT_CLR = 1 << UHCI_INT_OUTTOTALEOF;
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}
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}
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// ====================== Interface functions =========================
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void prog_init_pro_pre() {
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_uart_init();
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_pattern_init();
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}
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void prog_init_app() {
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}
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void prog_init_pro_post() {
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}
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void prog_cycle_app(uint64_t u64tckNow) {
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}
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void prog_cycle_pro(uint64_t u64tckNow) {
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_uart_cycle(u64tckNow);
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}

‎examples/Makefile.am‎

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AUTOMAKE_OPTIONS =
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SUBDIRS=0blink 0button 0hello 0ledctrl 0uart 1rmtblink 1rmtdht 1rmtmorse 1rmtmusic 1rmttm1637 3prog1 1rmtws2812
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SUBDIRS=0blink 0button 0hello 0ledctrl 0uart 0udma 1rmtblink 1rmtdht 1rmtmorse 1rmtmusic 1rmttm1637 3prog1 1rmtws2812

‎src/romfunctions.h‎

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#include <stdint.h>
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void ets_isr_unmask(uint32_t mask);
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void _xtos_set_interrupt_handler(int irq_number, void* function);
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void _xtos_set_interrupt_handler_arg(int irq_number, void* function, int argument);
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void *_xtos_set_interrupt_handler(int irq_number, void* function);
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void *_xtos_set_interrupt_handler_arg(int irq_number, void* function, int argument);
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void gpio_matrix_out(uint32_t gpio, uint32_t signal_idx, bool out_inv, bool oen_inv);
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void gpio_matrix_in(uint32_t gpio, uint32_t signal_idx, bool inv);

‎src/uart.h‎

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UDMA_CTL1
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} EUdmaController;
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typedef enum {
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UHCI_INT_RXSTART = 0,
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UHCI_INT_TXSTART,
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UHCI_INT_RXHUNG,
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UHCI_INT_TXHUNG,
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UHCI_INT_INDONE, // 4
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UHCI_INT_INSUCEOF,
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UHCI_INT_INERREOF,
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UHCI_INT_OUTDONE,
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UHCI_INT_OUTEOF, // 8
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UHCI_INT_INDSCRERR,
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UHCI_INT_OUTDSCRERR,
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UHCI_INT_INDSCREMPTY,
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UHCI_INT_OUTLINKEOFERR, // 12
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UHCI_INT_OUTTOTALEOF,
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UHCI_INT_SENDSREGQ,
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UHCI_INT_SENDAREGQ,
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UHCI_INT_DMAINFIFOFULLWM // 16
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} EUhciIntType; ///< Types of UHCI interrupt.
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// Based on:
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// https://github.com/espressif/esp-idf/blob/6b3da6b188/components/soc/esp32/include/soc/uart_reg.h
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