Enabling External PSRAM for Zephyr Applications on ESP32 SoCs · Espressif Developer Portal

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Enabling External PSRAM for Zephyr Applications on ESP32 SoCs · Espressif Developer Portal

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https://developer.espressif.com/blog/2024/12/zephyr-how-to-use-psram/

[letter57]

Hi, I was delighted to read your article, Enabling External PSRAM for Zephyr Applications on ESP32 SoCs, as I’ve been struggling to figure out how to use PSRAM on the ESP32-S3.

Referring to the article Letting ESP32 Wi-Fi Use PSRAM, I used the ESP32-S3-WROOM-1 N8R8 module and built zephyr/samples/net/wifi/shell with ESP32_WIFI_NET_ALLOC_SPIRAM enabled. After compiling and flashing it to the ESP32-S3-WROOM-1, I observed that the network stack allocations were made using memory from internal RAM addresses instead of PSRAM. Below are my relevant configurations and outputs.

-- Zephyr version: 4.0.0 (D:/Areas/Zephyr_IDE_4.0.0/external/zephyr), build: v4.0.0
[527/527] Linking C executable zephyr\zephyr.elf
Memory region         Used Size  Region Size  %age Used
           FLASH:      616440 B   16776960 B      3.67%
     iram0_0_seg:       88832 B     343552 B     25.86%
     dram0_0_seg:      167200 B     327168 B     51.11%
     irom0_0_seg:      384202 B        16 MB      2.29%
     drom0_0_seg:      485368 B        16 MB      2.89%
     ext_ram_seg:       1536 KB    8388544 B     18.75%
    rtc_iram_seg:          0 GB         8 KB      0.00%
    rtc_data_seg:          0 GB         8 KB      0.00%
    rtc_slow_seg:          0 GB         8 KB      0.00%
        IDT_LIST:          0 GB         8 KB      0.00%
Generating files from D:/Areas/Zephyr_IDE_4.0.0/shell/build/esp32s3_devkitc/esp32s3/procpu/zephyr/zephyr.elf for board: esp32s3_devkitc
esptool.py v4.7.0
Creating esp32s3 image...
Image has only RAM segments visible. ROM segments are hidden and SHA256 digest is not appended.
Merged 26 ELF sections
Successfully created esp32s3 image.

Here's my overlay

/*
 * Copyright (c) 2023 YuLong Yao<[email protected]>
 *
 * SPDX-License-Identifier: Apache-2.0
 */
 #include <zephyr/dt-bindings/mipi_dbi/mipi_dbi.h>

/ {
	
};

&i2c0 {
	status = "disabled";
};

&i2c1 {
	status = "disabled";
};

&twai {
	status = "disabled";
};

&uart2{
	status = "disabled";
};

arduino_spi: &spi3 {
	status = "disabled";
	//cs-gpios = <&gpio0 5 GPIO_ACTIVE_LOW>;
	pinctrl-0 = <&spim3_default>;
	clock-frequency = <10000000>;
};

&pinctrl {
	spim3_default: spim3_default {
		group1 {
			pinmux = <SPIM3_MISO_GPIO13>,
				 <SPIM3_SCLK_GPIO4>,
				 <SPIM3_CSEL_GPIO5>;
		};
		group2 {
			pinmux = <SPIM3_MOSI_GPIO2>;
			output-low;
		};
	};

	i2c1_default: i2c1_default {
		group1 {
			pinmux = <I2C1_SDA_GPIO15>,
				 <I2C1_SCL_GPIO7>;
			bias-pull-up;
			drive-open-drain;
			output-high;
		};
	};
};

/* 16MB flash */
&flash0 {
	reg = <0x0 DT_SIZE_M(16)>;
};

/* 8MB psram */
&psram0 {
	reg = <0x3c000000 DT_SIZE_M(8)>;
	status = "okay";
};

Here's my prj.conf

CONFIG_EARLY_CONSOLE=y

CONFIG_NETWORKING=y
CONFIG_TEST_RANDOM_GENERATOR=y

CONFIG_MAIN_STACK_SIZE=5200
CONFIG_SHELL_STACK_SIZE=5200
CONFIG_NET_TX_STACK_SIZE=2048
CONFIG_NET_RX_STACK_SIZE=2048

CONFIG_NET_PKT_RX_COUNT=10
CONFIG_NET_PKT_TX_COUNT=10
CONFIG_NET_BUF_RX_COUNT=20
CONFIG_NET_BUF_TX_COUNT=20
CONFIG_NET_MAX_CONTEXTS=10
CONFIG_NET_DHCPV4=y

CONFIG_NET_IPV4=y
CONFIG_NET_IPV6=n

CONFIG_NET_TCP=y

CONFIG_NET_LOG=y
CONFIG_INIT_STACKS=y

CONFIG_NET_SHELL=y

CONFIG_NET_STATISTICS=y
CONFIG_NET_STATISTICS_PERIODIC_OUTPUT=n

CONFIG_WIFI=y
CONFIG_WIFI_LOG_LEVEL_ERR=y
CONFIG_NET_L2_WIFI_SHELL=y
# printing of scan results puts pressure on queues in new locking
# design in net_mgmt. So, use a higher timeout for a crowded
# environment.
CONFIG_NET_MGMT_EVENT_QUEUE_TIMEOUT=5000
CONFIG_NET_MGMT_EVENT_QUEUE_SIZE=16

# PSRAM
CONFIG_LOG=y
CONFIG_ESP_SPIRAM=y
CONFIG_SPIRAM_MODE_OCT=y
CONFIG_SPIRAM_TYPE_ESPPSRAM64=y
CONFIG_SPIRAM_SPEED_80M=y
CONFIG_ESP32S3_DATA_CACHE_64KB=y
CONFIG_ESP_SPIRAM_MEMTEST=y

CONFIG_NET_DEBUG_NET_PKT_ALLOC=y
CONFIG_ESP32_WIFI_NET_ALLOC_SPIRAM=y

CONFIG_SPI=y

Below are the results of my execution output.

ESP-ROM:esp32s3-20210327
Build:Mar 27 2021
rst:0x1 (POWERON),boot:0x8 (SPI_FAST_FLASH_BOOT)
SPIWP:0xee
mode:DIO, clock div:2
load:0x3fc99b10,len:0x3ca4
load:0x40374000,len:0x15af0
SHA-256 comparison failed:
Calculated: 4764966f5b92f8b6d4eb02785da5598bc1ea6c6b11acaa31154d36e5899a1d4b
Expected: 0000000030680000000000000000000000000000000000000000000000000000
Attempting to boot anyway...
entry 0x4037ebbc
I (117) boot: ESP Simple boot
I (117) boot: compile time Jan  4 2025 22:35:51
W (117) boot: Unicore bootloader
I (117) spi_flash: detected chip: generic
I (119) spi_flash: flash io: dio
W (122) spi_flash: Detected size(8192k) larger than the size in the binary image header(2048k). Using the size in the binary image header.
I (135) boot: chip revision: v0.1
I (138) boot.esp32s3: Boot SPI Speed : 40MHz
I (142) boot.esp32s3: SPI Mode       : DIO
I (145) boot.esp32s3: SPI Flash Size : 8MB
I (149) boot: Enabling RNG early entropy source...
I (154) boot: DRAM: lma 0x00000020 vma 0x3fc99b10 len 0x3ca4   (15524)
I (160) boot: IRAM: lma 0x00003ccc vma 0x40374000 len 0x15af0  (88816)
I (166) boot: padd: lma 0x000197c8 vma 0x00000000 len 0x6830   (26672)
I (172) boot: IMAP: lma 0x00020000 vma 0x42000000 len 0x5dccc  (384204)
I (179) boot: padd: lma 0x0007dcd4 vma 0x00000000 len 0x2324   (8996)
I (185) boot: DMAP: lma 0x00080000 vma 0x3c060000 len 0x167f8  (92152)
I (191) boot: Image with 6 segments
I (194) boot: DROM segment: paddr=00080000h, vaddr=3c060000h, size=16800h ( 92160) map
I (202) boot: IROM segment: paddr=00020000h, vaddr=42000000h, size=5DCCAh (384202) map
I (221) octal_psram: vendor id    : 0x0d (AP)
I (222) octal_psram: dev id       : 0x02 (generation 3)
I (222) octal_psram: density      : 0x03 (64 Mbit)
I (224) octal_psram: good-die     : 0x01 (Pass)
I (228) octal_psram: Latency      : 0x01 (Fixed)
I (232) octal_psram: VCC          : 0x01 (3V)
I (236) octal_psram: SRF          : 0x01 (Fast Refresh)
I (241) octal_psram: BurstType    : 0x01 (Hybrid Wrap)
I (246) octal_psram: BurstLen     : 0x01 (32 Byte)
I (251) octal_psram: Readlatency  : 0x02 (10 cycles@Fixed)
I (256) octal_psram: DriveStrength: 0x00 (1/1)
I (261) MSPI Timing: PSRAM timing tuning index: 6
I (265) esp_psram: Found 8MB PSRAM device
I (268) esp_psram: Speed: 80MHz
I (717) esp_psram: SPI SRAM memory test OK
I (775) heap_runtime: ESP heap runtime init at 0x3fcb0d20 size 226 kB.


*** Booting Zephyr OS build v4.0.0 ***
[00:00:00.778,000] <inf> PSRAM_SAMPLE: Sample started
[00:00:00.860,000] <inf> PSRAM_SAMPLE: Sample finished successfully!
uart:~$ wifi scan
Scan requested

Num  | SSID                             (len) | Chan (Band)   | RSSI | Security        | BSSID             | MFP
1    | Janet`s Home                     12    | 3    (2.4GHz) | -27  | WPA2-PSK        | CC:D8:43:0A:A1:AD | Disable
2    | Cris                             4     | 2    (2.4GHz) | -46  | WPA2-PSK        | 5E:60:E4:09:4F:0A | Disable
3    | XQ117                            5     | 1    (2.4GHz) | -56  | WPA2-PSK        | BC:F8:7E:3E:48:50 | Disable
4    | 117-7F-1                         8     | 1    (2.4GHz) | -60  | WPA2-PSK        | 1C:61:B4:5C:B9:F6 | Disable
5    | janet_home                       10    | 11   (2.4GHz) | -75  | WPA2-PSK        | 58:13:D3:89:71:B4 | Disable
6    | Jiang                            5     | 4    (2.4GHz) | -94  | WPA2-PSK        | 5C:A6:E6:1E:E4:4A | Disable
Scan request done
uart:~$ wifi connect -k 1 -s Cris -p 0932963644
Connection requested
Connected
[00:00:36.368,000] <inf> net_dhcpv4: Received: 192.168.231.3
uart:~$ net iface

Interface wlan0 (0x3fc9d500) (WiFi) [1]
===============================
Link addr : 7C:DF:A1:FC:6F:9C
MTU       : 1500
Flags     : AUTO_START,IPv4
Device    : wifi (0x3c076210)
Ethernet capabilities supported:
Ethernet PHY device: <none> (0)
IPv4 unicast addresses (max 1):
        192.168.231.3/255.255.255.0 DHCP preferred
IPv4 multicast addresses (max 2):
        224.0.0.1
IPv4 gateway : 192.168.231.128
DHCPv4 lease time : 3599
DHCPv4 renew time : 1799
DHCPv4 server     : 192.168.231.128
DHCPv4 requested  : 192.168.231.3
DHCPv4 state      : bound
DHCPv4 attempts   : 1
uart:~$ net ping 192.168.231.128
PING 192.168.231.128
28 bytes from 192.168.231.128 to 192.168.231.3: icmp_seq=1 ttl=64 time=20 ms
28 bytes from 192.168.231.128 to 192.168.231.3: icmp_seq=2 ttl=64 time=263 ms
28 bytes from 192.168.231.128 to 192.168.231.3: icmp_seq=3 ttl=64 time=65 ms
uart:~$ net allocs
Network memory allocations

memory          Status  Pool    Function alloc -> freed
0x3fcaf330       free      RX   eth_esp32_rx():135 -> net_icmpv4_input():647
0x3fcae26c       free   TDATA   ethernet_fill_header():532 -> ethernet_remove_l2_header():615
0x3fcae26c       free   TDATA   ethernet_fill_header():532 -> ethernet_remove_l2_header():615
uart:~$ 

[wmrsouza]

Hi @letter57, we are glad you are enjoying the reading.

At first glance it looks like you did everything right. Could you share your evironment and the command line you used to build the application?

I repeated the experiments on my side and it worked as expected: memory was allocated from PSRAM. Comparing your log with mine, it seems you are out of sync with the Zephyr main branch:
*** Booting Zephyr OS build v4.0.0 ***:

Do you mind updating to the Zephyr main branch, repeating the experiments, and let me know about the results? (Don't forget to run west update and west blobs fetch hal_espressif right after syncing with Zephyr main branch)

[rftafas]

Hi, @letter57, please, move this discussion to Zephyr Discussion Channel, as this place is more focused for 'article reviews'.

Well, since we are here, please, update to latest commit in Zephyr's repo. There were fixes. If you have further questions, please, use Discord, GH issues or Discussion channel on Zephyr GH.

We can close this.

[letter57]

Hi, @rftafas I didn't know I can't reply my question here. I am sorry. If I encounter any issues in the future, I will discuss them in the Zephyr Discussion Channel. Thank you.

[letter57]

Hi, @wmrsouza Thank you for your response. First, I realized that I overlooked the Zephyr main branch and mistakenly thought that Zephyr 4.0.0 already supported external PSRAM for Zephyr.

After switching to the Zephyr main branch, the test results were exactly as described in your article. I really appreciate you.