view src/cs/services/tty/tty_env.c @ 220:0ed36de51973

ABB semaphore protection overhaul The ABB semaphone protection logic that came with TCS211 from TI was broken in several ways: * Some semaphore-protected functions were called from Application_Initialize() context. NU_Obtain_Semaphore() called with NU_SUSPEND fails with NU_INVALID_SUSPEND in this context, but the return value wasn't checked, and NU_Release_Semaphore() would be called unconditionally at the end. The latter call would increment the semaphore count past 1, making the semaphore no longer binary and thus no longer effective for resource protection. The fix is to check the return value from NU_Obtain_Semaphore() and skip the NU_Release_Semaphore() call if the semaphore wasn't properly obtained. * Some SPI hardware manipulation was being done before entering the semaphore- protected critical section. The fix is to reorder the code: first obtain the semaphore, then do everything else. * In the corner case of L1/DSP recovery, l1_abb_power_on() would call some non-semaphore-protected ABB & SPI init functions. The fix is to skip those calls in the case of recovery. * A few additional corner cases existed, all of which are fixed by making ABB semaphore protection 100% consistent for all ABB functions and code paths. There is still one remaining problem of priority inversion: suppose a low- priority task calls an ABB function, and some medium-priority task just happens to preempt right in the middle of that semaphore-protected ABB operation. Then the high-priority SPI task is locked out for a non-deterministic time until that medium-priority task finishes its work and goes back to sleep. This priority inversion problem remains outstanding for now.
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 26 Apr 2021 20:55:25 +0000
parents 4e78acac3d88
children
line wrap: on
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/**
 * @file	tty_env.c
 *
 * Coding of the Riviera Generic Functions,
 * except handle_message and handle_timer, which are
 * in tty_handle_message.c and tty_handle_timer.c
 *
 * @author	Frederic Turgis (f-turgis@ti.com) & Gerard Cauvy (g-cauvy@ti.com)
 * @version 0.1
 */

/*
 * History:
 *
 * 	Date       	Modification
 *  ------------------------------------
 *  01/27/2003	Create
 *
 * (C) Copyright 2003 by Texas Instruments Incorporated, All Rights Reserved
 */


#include "tty/tty_i.h"

#include "rvm/rvm_priorities.h"
#include "tty/tty_env.h"
#include <string.h>

/**
 * Pointer on the structure gathering all the global variables
 * used by TTY instance.
 */
T_TTY_ENV_CTRL_BLK *tty_env_ctrl_blk_p = NULL;


/* External declaration */
extern T_RV_RET tty_core(void);

/**
 * Called by the RV manager to learn 
 * tty requirements in terms of memory, SWEs...
 *
 * @param	swe_info	Pointer to the structure to fill
 *						containing infos related to the tty SWE.
 *
 * @return	RVM_OK
 */
T_RVM_RETURN tty_get_info(T_RVM_INFO_SWE  * swe_info)
{
	/* TTY is a Type 4 SWE. */
	swe_info->swe_type = RVM_SWE_TYPE_4;

	memcpy(swe_info->type_info.type4.swe_name, "TTY", sizeof("TTY"));
	swe_info->type_info.type4.swe_use_id = TTY_USE_ID;

	/* SWE info */
	swe_info->type_info.type4.stack_size	= TTY_STACK_SIZE;
	swe_info->type_info.type4.priority		= RVM_TTY_TASK_PRIORITY;
	swe_info->type_info.type4.version		= BUILD_VERSION_NUMBER(0,1,0);

	/* Memory bank info */
	swe_info->type_info.type4.nb_mem_bank = 1;
	memcpy(swe_info->type_info.type4.mem_bank[0].bank_name, "TTY_PRIM", sizeof("TTY_PRIM"));
	swe_info->type_info.type4.mem_bank[0].initial_params.size		= TTY_MB_PRIM_SIZE;
	swe_info->type_info.type4.mem_bank[0].initial_params.watermark	= TTY_MB_PRIM_WATERMARK;
	
	/* 
	 * Linked SWE info.
	 */
	swe_info->type_info.type4.nb_linked_swe = 0;

	/* Set the return path: NOT USED. */
	swe_info->type_info.type4.return_path.callback_func	= NULL;
	swe_info->type_info.type4.return_path.addr_id		= 0;

	/* Generic functions */
	swe_info->type_info.type4.set_info		 = tty_set_info;
	swe_info->type_info.type4.init			 = tty_init;
	swe_info->type_info.type4.core			 = tty_core;
	swe_info->type_info.type4.stop			 = tty_stop;
	swe_info->type_info.type4.kill			 = tty_kill;

	return RVM_OK;
}


/**
 * Called by the RV manager to inform the tty SWE about 
 * addr_id, return path, mb_id and error function.
 *
 * It is called only once.
 *
 * @param	addr_id			Address ID of the TTY SWE.
 *							Used to send messages to the SWE.
 * @param	return_path		Return path array of the linked SWEs.
 * @param	bk_id_table		Array of memory bank ids allocated to the SWE.
 * @param	call_back_error_ft Callback function to call in case of unrecoverable error.
 * @return	RVM_MEMORY_ERR ou RVM_OK.
 */
T_RVM_RETURN tty_set_info ( T_RVF_G_ADDR_ID		addr_id,
							T_RV_RETURN_PATH	return_path[], 
							T_RVF_MB_ID			bk_id_table[],
							T_RVM_CB_FUNC		call_back_error_ft)
{
	/* Memory bank status (red, yellow, green). */
	T_RVF_MB_STATUS mb_status;

	
	/* Create instance gathering all the variable used by TTY instance */
	mb_status = rvf_get_buf(bk_id_table[0], 
							sizeof(T_TTY_ENV_CTRL_BLK),
							(T_RVF_BUFFER**)&tty_env_ctrl_blk_p);
	if (mb_status == RVF_RED)
	{
		TTY_SEND_TRACE("TTY: Error to get memory ",RV_TRACE_LEVEL_ERROR);
		return RVM_MEMORY_ERR;
	}
	else if (mb_status == RVF_YELLOW)
	{
		/*
		 * The flag is yellow, there will soon be not enough memory anymore.
		 */
		TTY_SEND_TRACE("TTY: Getting short on memory ", RV_TRACE_LEVEL_WARNING);
	}

	/* Store the initial State; default is IDLE. */
	tty_env_ctrl_blk_p->state = TTY_IDLE;

	/* Store the address ID. */
	tty_env_ctrl_blk_p->addr_id = addr_id;

	/* Store the pointer to the error function. */
	tty_env_ctrl_blk_p->error_ft = call_back_error_ft;

	/*
	 * Store the mem bank id.
	 * Memory bank ID (mb_id) can be retrieved later using rvf_get_mb_id function.
	 */
	tty_env_ctrl_blk_p->prim_mb_id = bk_id_table[0];

	/*
	 * Array return_path: Return path of linked SWE.
	 * If the linked SWE have an API based on messages, their return path given 
	 * by the set_info function would be stored and used to communicate with them.
	 * But since the linked SWE of TTY have an API based on functions, it is not
	 * necessary to store their return path.
	 */

	return RVM_OK;
}


/**
 * Called by the RV manager to initialize the 
 * tty SWE before creating the task and calling tty_start. 
 *
 * @return	RVM_OK
 */
T_RVM_RETURN tty_init (void)
{
	/*
	 * TTY Global Initialization.
	 */

	return RVM_OK;
}


/**
 * Called by the RV manager to stop the tty SWE.
 *
 * @return	RVM_OK or RVM_INTERNAL_ERR
 */
T_RVM_RETURN tty_stop (void)
{
	/*
	 * Here we should stop the activities of the SWE
	 * It is still possible to send messages to other SWE, to unregister for example.
	 */
	TTY_SEND_TRACE("TTY: stop called", RV_TRACE_LEVEL_DEBUG_LOW);

	return RVM_OK;
}


/**
 * Called by the RV manager to kill the tty SWE,
 * after the tty_stop function has been called.
 *
 * @return	RVM_OK
 */
T_RVM_RETURN tty_kill (void)
{
	/*
	 * Here we cannot send messages anymore. We only free the last
	 * used resources, like the control block buffer.
	 */
	TTY_SEND_TRACE("TTY: kill called", RV_TRACE_LEVEL_DEBUG_LOW);

	rvf_free_buf(tty_env_ctrl_blk_p);

	return RVM_OK;
}