[FAQ] [参考译文] [常见问题解答] PROCESSOR-SDK-AM64X：从 PRU-ICSSG 访问 DDR

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请注意，本文内容源自机器翻译，可能存在语法或其它翻译错误，仅供参考。如需获取准确内容，请参阅链接中的英语原文或自行翻译。

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1236795/faq-processor-sdk-am64x-accessing-ddr-from-pru-icssg

器件型号：PROCESSOR-SDK-AM64X
主题中讨论的其他器件：SysConfig

您好！

您能帮助我从 PRU 内核访问 DDR 吗？

。

此常见问题解答中的信息适用于所有具有 PRU_ICSSG 的 Sitara 处理器：AM24x、AM64x、AM65x。在 AM64x 上测试了该示例。

此常见问题解答的基本概念也适用于采用其他类型 PRU 子系统的 Sitara 处理器：

AM335x、AM437x、AM57x：
有关如何从 CCS 或 Linux 内核初始化 PRU 内核的信息、请参阅 PRU 入门实验。这些较旧的 PRU-ICSS 器件需要先启用 OCP 端口、然后再允许在 PRU 子系统之外进行读取和写入。有关启用 OCP 端口的示例、请参考相关器件的 RPMsg_Echo_Interrupt 固件： https://git.ti.com/cgit/pru-software-support-package/pru-software-support-package/tree/examples/am335x/PRU_RPMsg_Echo_Interrupt0/main.c

AM62x：有关如何从 CCS 或 Linux 内核初始化 PRU 内核的信息、请参阅 PRU 入门实验。

。

有关多核主题的更多信息、请参阅 Sitara 多核开发和文档常见问题解答。

有关 PRU 的"入门"信息、包括如何从 CCS 或 Linux 内核初始化 PRU 内核、请参阅 PRU 入门实验。

1 年多前

0 admin 1 年多前

TI__Guru**** 1134490 points

请注意，本文内容源自机器翻译，可能存在语法或其它翻译错误，仅供参考。如需获取准确内容，请参阅链接中的英语原文或自行翻译。

此示例将使用 IEP 计时器对存储器访问进行时间戳记。但是、PRU_CYCLE 寄存器也可用于计算存储器访问占用的时钟周期数。有关使用 PRU_CYCLE 寄存器的详细信息、请参考这篇文章。

前提条件：

遵循入门步骤(请参阅 https://software-dl.ti.com/mcu-plus-sdk/esd/AM64X/08_05_00_24/exports/docs/api_guide_am64x/GETTING_STARTED.html)

导入和构建 Hello World 示例(请参见 https://software-dl.ti.com/mcu-plus-sdk/esd/AM64X/latest/exports/docs/api_guide_am64x/GETTING_STARTED_BUILD.html)

如下所示更新 hello_world.c 文件(添加 while (1)；)

/*
 *  Copyright (C) 2018-2021 Texas Instruments Incorporated
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *    Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 *    Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the
 *    distribution.
 *
 *    Neither the name of Texas Instruments Incorporated nor the names of
 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
 
#include <stdio.h>
#include <kernel/dpl/DebugP.h>
#include "ti_drivers_config.h"
#include "ti_drivers_open_close.h"
#include "ti_board_open_close.h"
 
void hello_world_main(void *args)
{
    /* Open drivers to open the UART driver for console */
    Drivers_open();
    Board_driversOpen();
 
    DebugP_log("Hello World!\r\n");
 
    while(1);
 
    Board_driversClose();
    Drivers_close();
}

更改了 example.sysconfig
1. 添加 PRU 实例
2. 将 IEP clk 值更新为500MHz 以获取价格时间戳
重新构建
导入和编译 CCS 工程(C：\MCU_PLUS_SDK\examples\PRU_IO\empty\firmware\am64x-evm)

如下所示更新 main.asm 文件()

请参阅 TRM 第6.4.12节 PRU_ICSSG_IEP 了解 IEP 时间戳
main.asm 文件如下所示

; Copyright (C) 2022 Texas Instruments Incorporated - http://www.ti.com/
;
; Redistribution and use in source and binary forms, with or without
; modification, are permitted provided that the following conditions
; are met:
;
; Redistributions of source code must retain the above copyright
; notice, this list of conditions and the following disclaimer.
;
; Redistributions in binary form must reproduce the above copyright
; notice, this list of conditions and the following disclaimer in the
; documentation and/or other materials provided with the
; distribution.
;
; Neither the name of Texas Instruments Incorporated nor the names of
; its contributors may be used to endorse or promote products derived
; from this software without specific prior written permission.
;
; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
; A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
; OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
; SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
; LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
; DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
; THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
; OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
;************************************************************************************
;   File:     main.asm
;
;   Brief:    Template asm file example
;************************************************************************************
 
; CCS/makefile specific settings
    .retain     ; Required for building .out with assembly file
    .retainrefs ; Required for building .out with assembly file
 
    .global     main
    .sect       ".text"
 
;************************************* includes *************************************
; icss_constant_defines.inc: Defines symbols corresponding to Constant Table Entries
    .include "icss_constant_defines.inc"
 
    .asg    R2, IEP_CFG_REG
    .asg    R3, IEP_COUNT_REG0
    .asg    R4, IEP_COUNT_REG1
    .asg    R8, TEMP_REG
 
;********
;* MAIN *
;********
 
main:
 
init:
;----------------------------------------------------------------------------
;   Clear the register space
;   Before begining with the application, make sure all the registers are set
;   to 0. PRU has 32 - 4 byte registers: R0 to R31, with R30 and R31 being special
;   registers for output and input respectively.
;----------------------------------------------------------------------------
 
; Give the starting address and number of bytes to clear.
    zero    &r0, 120
 
;----------------------------------------------------------------------------
;   Constant Table Entries Configuration
;   Sample code to configure Constant Table Entries.
;----------------------------------------------------------------------------
 
; Configure the Constant Table entry C28 to point to start of shared memory
; PRU_ICSSG Shared RAM (local-C28) : 00nn_nn00h, nnnn = c28_pointer[15:0]
; By default it is set to 0000_0000h so it will point to DMEM0 address
    ldi     TEMP_REG, 0x0100
    sbco    &TEMP_REG, ICSS_PRU_CTRL_CONST, 0x28, 2
 
; Load 32 bit value to TEMP_REG reg
; To load values greater than 16 bits, we use ldi32 which performs ldi 2 times
; - for lsb 16 bits and then for msb 16 bits
    ldi32   TEMP_REG, 0x12345678
 
 
;----------------------------------------------------------------------------
;   Reading and Writing latency calculation for DDR from PRU
;----------------------------------------------------------------------------
 
    ldi32 R15, 0x80000000 ; DDR base address
    ;ldi R15.w0, 0
    ldi32 R5 ,0x04 ; data to write in DDR
    ldi32 R6, 0x00 ; data to read from DDR
    ldi32 R7, 0x00; counter status
    ldi32 R8, 0x00 ; counter value1
    ldi32 R9, 0x00 ; counter value2
    ldi32 R10, 0x00 ; counter value3
 
;----------------------------------------------------------------------------
;   Initiaizae IEP
;----------------------------------------------------------------------------
 
 ;IEP_CNT_ENABLE
    lbbo R7, ICSS_IEP1_0_CONST, 0, 4
    OR R7, R7, 0x00000001
    sbbo R7, ICSS_IEP1_0_CONST, 0, 4
 
;Read IEP_COUNT_REG0
    lbbo R8, ICSS_IEP1_0_CONST, 0x10, 4 ; T0 in ns
 
; writing R5 => DDR => R6
    sbbo &R5, R15, 0, 0x02
 
;Read IEP_COUNT_REG0
    lbbo R9, ICSS_IEP1_0_CONST, 0x10, 4 ; T1 in ns
 
; Reading DDR => R6
    lbbo &R6, R15, 0, 0x02
 
;Read IEP_COUNT_REG0
    lbbo R8, ICSS_IEP1_0_CONST, 0x10, 4 ; T2 in ns
 
; T1-T0 - 3 PRU_CYCLE = DDR Write Time Latency
 
; T2-T1 - 3 PRU_CYCLE = DDR Read Time Latency
 
; Write 4 byte register value to DMEM0 at offset 0x14
    sbco    &TEMP_REG, ICSS_DMEM0_CONST, 0x14, 4
 
; Write 3 byte register value to DMEM1 at offset 0x10
    sbco    &TEMP_REG, ICSS_DMEM1_CONST, 0x10, 3
 
; Write 2 byte register value to SMEM0 at offset 0x22
    sbco    &TEMP_REG, ICSS_SMEM_CONST,  0x22, 2
 
    halt ; end of program

重新构建

假设遵循 OSPI 加载方法(因为该方法将负责 DDR 的初始化)
1. 请参阅https://software-dl.ti.com/mcu-plus-sdk/esd/AM64X/latest/exports/docs/api_guide_am64x/EVM_SETUP_PAGE.html"的"Flash SOC 初始化二进制"部分
连接 R5F_0_0
加载二进制
运行它
现在、连接 PRU_0或 PRU_1并将其作为
加载二进制
添加断点
运行它
将达到断点
然后、转到菜单栏=> View => Registers
检查所选 PRU 的 R2和 R4寄存器的内容
1. 应为0x00000004

此致

处理器（参考译文帖）

处理器（参考译文帖）(Read Only)

[FAQ] [参考译文] [常见问题解答] PROCESSOR-SDK-AM64X：从 PRU-ICSSG 访问 DDR