Simplified application development

Oct 13, 2025 by magicalceylontours.com 138 views

Problem Statement

The original problem statement arose on the ESP-Matter GitHub issue #1249. The issue revolves around the compatibility of the SPI flash driver with stacks in PSRAM (Programmable Serial RAM). The problem is that the SPI flash driver is not designed to work with stacks in PSRAM, which is a common configuration for systems running Lua. Lua uses a lot of stack space, and allocating it in internal RAM can lead to issues with flash calls, such as file systems and OTA (Over-the-Air) updates.

Use Case

The use case is a system running Lua, which uses a lot of stack space. To allocate more room, it is easy to give Lua a PSRAM-based stack. However, this leads to issues with flash calls, such as file systems and OTA updates. The problem is not simple to fix in the application, as everything that touches flash needs to be fixed not to use PSRAM stacks. This is a lot of work and error-prone.

Solution

The proposed solution is to add a menuconfig option in the SPI flash driver to use a private stack for internal operations. Alternatively, the SPI flash component can check the stack pointer and switch stacks automatically if it is in PSRAM. This would make it easier to use PSRAM-based stacks for Lua and other applications that require a lot of stack space.

Benefits

The proposed solution has several benefits:

Simplified application development: With the SPI flash driver using a private stack, application developers do not need to worry about switching stacks or fixing issues with flash calls.
Reduced development time: The proposed solution reduces the development time and effort required to fix issues with flash calls.
Improved reliability: The proposed solution improves the reliability of the system by reducing the risk of errors and crashes due to stack overflows.

Alternatives

There are several alternatives to the proposed solution:

Fixing the problem at every call site in the user app: This is a lot of work and error-prone. It requires developers to manually switch stacks and fix issues with flash calls at every call site.
Using a different flash driver: This may not be possible or desirable, as the SPI flash driver is a critical component of the system.

Additional Context

The original problem statement was raised on the ESP-Matter GitHub issue #1249. There was no response to the issue, which highlights the need for a solution to this problem.

Implementation

To implement the proposed solution, the following steps can be taken:

Add a menuconfig option: Add a menuconfig option to the SPI flash driver to use a private stack for internal operations.
Check the stack pointer: Check the stack pointer in the SPI flash component and switch stacks automatically if it is in PSRAM.
Test the solution: Test the solution to ensure that it works correctly and does not introduce any new issues.

Conclusion

In conclusion, the proposed solution to modify the SPI flash driver to be compatible with stacks in PSRAM is a simple and effective way to solve the problem. It reduces the development time and effort required to fix issues with flash calls and improves the reliability of the system. The implementation of the solution involves adding a menuconfig option and checking the stack pointer in the SPI flash component.

Future Work

Future work on this project can include:

Testing the solution: Testing the solution to ensure that it works correctly and does not introduce any new issues.
Refining the solution: Refining the solution to make it more efficient and effective.
Documenting the solution: Documenting the solution to make it easier for others to understand and implement.

Code

The code for the proposed solution can be found in the following files:

spi_flash.c: This file contains the implementation of the SPI flash driver.
spi_flash.h: This file contains the header file for the SPI flash driver.
menuconfig.h: This file contains the menuconfig options for the SPI flash driver.

The code can be modified to implement the proposed solution. The following is an example of how the code can be modified:

// spi_flash.c

#include "spi_flash.h"
#include "menuconfig.h"

// Function to check if the stack pointer is in PSRAM
static bool is_stack_in_psram(void)
{
    // Check if the stack pointer is in PSRAM
    if (get_stack_pointer() >= PSRAM_BASE_ADDRESS)
    {
        return true;
    }
    return false;
}

// Function to switch stacks
static void switch_stacks(void)
{
    // Switch stacks to the private stack
    set_stack_pointer(PRIVATE_STACK_BASE_ADDRESS);
}

// Function to perform SPI flash operations
static void spi_flash_operations(void)
{
    // Check if the stack pointer is in PSRAM
    if (is_stack_in_psram())
    {
        // Switch stacks to the private stack
        switch_stacks();
    }
    // Perform SPI flash operations
    // ...
}

// Function to initialize the SPI flash driver
void spi_flash_init(void)
{
    // Initialize the SPI flash driver
    // ...
    // Set the menuconfig option to use a private stack
    set_menuconfig_option(MENUCONFIG_SPI_FLASH_USE_PRIVATE_STACK, true);
}

// spi_flash.h

#ifndef SPI_FLASH_H
#define SPI_FLASH_H

// Function to check if the stack pointer is in PSRAM
bool is_stack_in_psram(void);

// Function to switch stacks
void switch_stacks(void);

// Function to perform SPI flash operations
void spi_flash_operations(void);

// Function to initialize the SPI flash driver
void spi_flash_init(void);

#endif  // SPI_FLASH_H

// menuconfig.h

#ifndef MENUCONFIG_H
#define MENUCONFIG_H

// Menuconfig option to use a private stack
#define MENUCONFIG_SPI_FLASH_USE_PRIVATE_STACK 1

#endif  // MENUCONFIG_H

Q: What is the problem with the current SPI flash driver?

A: The current SPI flash driver is not designed to work with stacks in PSRAM (Programmable Serial RAM). This can lead to issues with flash calls, such as file systems and OTA (Over-the-Air) updates, when running Lua or other applications that require a lot of stack space.

Q: What is the proposed solution to this problem?

A: The proposed solution is to add a menuconfig option in the SPI flash driver to use a private stack for internal operations. Alternatively, the SPI flash component can check the stack pointer and switch stacks automatically if it is in PSRAM.

Q: What are the benefits of the proposed solution?

A: The proposed solution has several benefits, including:

Simplified application development: With the SPI flash driver using a private stack, application developers do not need to worry about switching stacks or fixing issues with flash calls.
Reduced development time: The proposed solution reduces the development time and effort required to fix issues with flash calls.
Improved reliability: The proposed solution improves the reliability of the system by reducing the risk of errors and crashes due to stack overflows.

Q: What are the alternatives to the proposed solution?

A: There are several alternatives to the proposed solution, including:

Fixing the problem at every call site in the user app: This is a lot of work and error-prone. It requires developers to manually switch stacks and fix issues with flash calls at every call site.
Using a different flash driver: This may not be possible or desirable, as the SPI flash driver is a critical component of the system.

Q: How can the proposed solution be implemented?

A: To implement the proposed solution, the following steps can be taken:

Add a menuconfig option: Add a menuconfig option to the SPI flash driver to use a private stack for internal operations.
Check the stack pointer: Check the stack pointer in the SPI flash component and switch stacks automatically if it is in PSRAM.
Test the solution: Test the solution to ensure that it works correctly and does not introduce any new issues.

Q: What is the code for the proposed solution?

A: The code for the proposed solution can be found in the following files:

spi_flash.c: This file contains the implementation of the SPI flash driver.
spi_flash.h: This file contains the header file for the SPI flash driver.
menuconfig.h: This file contains the menuconfig options for the SPI flash driver.

The code can be modified to implement the proposed solution. The following is an example of how the code can be modified:

// spi_flash.c

#include "spi_flash.h"
#include "menuconfig.h"

// Function to check if the stack pointer is in PSRAM
static bool is_stack_in_psram(void)
{
    // Check if the stack pointer is in PSRAM
    if (get_stack_pointer() >= PSRAM_BASE_ADDRESS)
    {
        return true;
    }
    return false;
}

// Function to switch stacks
static void switch_stacks(void)
{
    // Switch stacks to the private stack
    set_stack_pointer(PRIVATE_STACK_BASE_ADDRESS);
}

// Function to perform SPI flash operations
static void spi_flash_operations(void)
{
    // Check if the stack pointer is in PSRAM
    if (is_stack_in_psram())
    {
        // Switch stacks to the private stack
        switch_stacks();
    }
    // Perform SPI flash operations
    // ...
}

// Function to initialize the SPI flash driver
void spi_flash_init(void)
{
    // Initialize the SPI flash driver
    // ...
    // Set the menuconfig option to use a private stack
    set_menuconfig_option(MENUCONFIG_SPI_FLASH_USE_PRIVATE_STACK, true);
}

// spi_flash.h

#ifndef SPI_FLASH_H
#define SPI_FLASH_H

// Function to check if the stack pointer is in PSRAM
bool is_stack_in_psram(void);

// Function to switch stacks
void switch_stacks(void);

// Function to perform SPI flash operations
void spi_flash_operations(void);

// Function to initialize the SPI flash driver
void spi_flash_init(void);

#endif  // SPI_FLASH_H

// menuconfig.h

#ifndef MENUCONFIG_H
#define MENUCONFIG_H

// Menuconfig option to use a private stack
#define MENUCONFIG_SPI_FLASH_USE_PRIVATE_STACK 1

#endif  // MENUCONFIG_H

Q: What are the next steps for this project?

A: The next steps for this project include:

Testing the solution: Testing the solution to ensure that it works correctly and does not introduce any new issues.
Refining the solution: Refining the solution to make it more efficient and effective.
Documenting the solution: Documenting the solution to make it easier for others to understand and implement.

Q: What are the benefits of this project?

A: The benefits of this project include:

Improved reliability: The proposed solution improves the reliability of the system by reducing the risk of errors and crashes due to stack overflows.
Simplified application development: With the SPI flash driver using a private stack, application developers do not need to worry about switching stacks or fixing issues with flash calls.
Reduced development time: The proposed solution reduces the development time and effort required to fix issues with flash calls.