flash_gate.h File Reference

When the panel may write its own flash, and when the IOmcu may not write its own. More...

#include <stdbool.h>

Go to the source code of this file.

Functions
bool	flash_gate_open (bool armed, bool supply)
	Whether a flash operation may start now.
bool	flash_gate_busy (bool driving, bool supply_on, bool pd_on, bool kst_session)
	Whether the IOmcu's flash may not be written now, for the store and for the firmware update alike.

Detailed Description

When the panel may write its own flash, and when the IOmcu may not write its own.

CONFIG_SPI_FLASH_AUTO_SUSPEND is off on the panel, so an erase or a write of its main flash disables the cache and stalls both cores for its length: code that is not in IRAM (instruction RAM) runs nowhere. The control task is not in IRAM. It beats the safety line, whose ceiling is HEARTBEAT_MAX_GAP_MS (150ms), and it carries STOP, OUTPUT OFF and the supply's trips. One 4kB sector erase is tens of milliseconds; a bench that is armed, or whose supply is live, must not wait for one.

So a flash write starts only on a bench that is disarmed with the supply off. Every writer of the panel's flash asks this one rule: the settings save before it commits a page of NVS (non-volatile storage), and the board drawing's keeper before each sector. A write that is not allowed waits; arming and the supply are never refused for one.

The IOmcu's rule is flash_gate_busy(), for its output store and its firmware update alike.

Pure C, no ESP-IDF (Espressif Internet-of-Things Development Framework).

SPDX-License-Identifier: MIT

Function Documentation

flash_gate_busy()

bool flash_gate_busy	(	bool	driving,
		bool	supply_on,
		bool	pd_on,
		bool	kst_session )

Whether the IOmcu's flash may not be written now, for the store and for the firmware update alike.

The bank driving: a window stops this core and steps no output. The supply asked on or perhaps on: its UART replies would overrun the 8-byte FIFO in a 19ms window, and an OFF asked over the link would wait for it. A KST session: a flash write stalls the pass that steps it.

False only when all four arguments are false.

Parameters

driving	true when the bank is driving (outputs_driving()).
supply_on	true when the SUPPLY page's output register is non-zero.
pd_on	true when the PD mini is open and may be on (pdmini_may_be_on()).
kst_session	true when the KST port is out of PWM.

Returns

true when the flash may not be written.

flash_gate_open()

bool flash_gate_open	(	bool	armed,
		bool	supply )

Whether a flash operation may start now.

True only when both armed and supply are false.

Parameters

armed	true when the bank is armed, or an arm is waiting for the line to settle (arming_link_needed()): a stall inside the settle can cost the far end's trust in the heartbeat and so the arm.
supply	true when the supply's output is on, or an ON for it is queued and not yet taken.

Returns

true when a flash operation may start.