FreeCalypso > hg > fc-tourmaline
view src/cs/services/atp/atp_uart_api.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 |
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/********************************************************************************/ /* */ /* File Name: atp_uart_api.c */ /* */ /* Purpose: This file contains the external functions related to */ /* the ATP-UART interface. */ /* */ /* Note: None. */ /* */ /* Revision History: */ /* 10/04/01 Pascal Pompei */ /* - Create. */ /* */ /* (C) Copyright 2001 by Texas Instruments Incorporated, All Rights Reserved. */ /* */ /********************************************************************************/ #include "atp/atp_uart_i.h" #include "rvm/rvm_use_id_list.h" /********************************************************************************/ /* */ /* Function Name: atp_uart_open_com_port */ /* */ /* Purpose: This function instructs the ATP-UART interface to open */ /* the COM port. */ /* */ /* Input Parameters: */ /* com_port - Contains the COM port number. */ /* baud_rate - Contains the baud rate (in bits per second). */ /* */ /* Output Parameters: None. */ /* */ /* Global Parameters: None. */ /* */ /* Note: None. */ /* */ /* Revision History: */ /* 10/04/01 Pascal Pompei */ /* - Create. */ /* */ /********************************************************************************/ T_ATP_UART_ERROR_CODES atp_uart_open_com_port (T_ATP_UART_COM_PORT com_port, T_ATP_UART_BAUD_RATE baud_rate) { /* Declare a local variable. */ T_ATP_UART_OPEN_COM_PORT *open_com_port_p = NULL; /******************** atp_uart_open_com_port function begins ********************/ /* Allocate memory required to instruct the ATP-UART interface to open the */ /* COM port. If insufficient resources, then report an internal memory */ /* error and abort. */ if (rvf_get_buf (gbl_atp_uart_ctrl_blk_p->mb_id, \ sizeof (T_ATP_UART_OPEN_COM_PORT), \ (T_RVF_BUFFER **) (&open_com_port_p)) == RVF_RED) { rvf_send_trace (" ATP-UART (api). Insufficient resources ", 41, NULL_PARAM, RV_TRACE_LEVEL_WARNING, ATP_USE_ID); return (RV_MEMORY_ERR); } /* Fill the 'ATP-UART Open COM Port' header up. */ (open_com_port_p->os_header).msg_id = ATP_UART_OPEN_COM_PORT; (open_com_port_p->os_header).src_addr_id = RVF_INVALID_ADDR_ID; (open_com_port_p->os_header).callback_func = NULL; /* Fill the 'ATP-UART Open COM Port' payload up. */ open_com_port_p->com_port = com_port; open_com_port_p->baud_rate = baud_rate; /* Send the 'ATP-UART Open COM Port' notification to the ATP-UART */ /* interface. */ return (rvf_send_msg (gbl_atp_uart_ctrl_blk_p->addr_id, \ open_com_port_p)); } /******************* End of atp_uart_open_com_port function *******************/ /********************************************************************************/ /* */ /* Function Name: atp_uart_start_gsm */ /* */ /* Purpose: This function instructs the ATP-UART interface to */ /* initiate using the GSM protocol stack. */ /* */ /* Input Parameters: None. */ /* */ /* Output Parameters: None. */ /* */ /* Global Parameters: None. */ /* */ /* Note: The GSM protocol stack is initialized by invoking the */ /* following AT commands: */ /* AT+CFUN=1 : Set Phone Functionality (Full), */ /* AT+COPS=0 : Operator Selection. */ /* */ /* Revision History: */ /* 09/26/02 Pascal Pompei */ /* - Create. */ /* */ /********************************************************************************/ T_ATP_UART_ERROR_CODES atp_uart_start_gsm (void) { /* Declare a local variable. */ T_ATP_UART_START_GSM *start_gsm_p = NULL; /********************** atp_uart_start_gsm function begins **********************/ /* Allocate memory required to instruct the ATP-UART interface to initiate */ /* using the GSM protocol stack. If insufficient resources, then report an */ /* internal memory error and abort. */ if (rvf_get_buf (gbl_atp_uart_ctrl_blk_p->mb_id, \ sizeof (T_ATP_UART_START_GSM), \ (T_RVF_BUFFER **) (&start_gsm_p)) == RVF_RED) { rvf_send_trace (" ATP-UART (api). Insufficient resources ", 41, NULL_PARAM, RV_TRACE_LEVEL_WARNING, ATP_USE_ID); return (RV_MEMORY_ERR); } /* Fill the 'ATP-UART Start GSM' header up. */ (start_gsm_p->os_header).msg_id = ATP_UART_START_GSM; (start_gsm_p->os_header).src_addr_id = RVF_INVALID_ADDR_ID; (start_gsm_p->os_header).callback_func = NULL; /* Send the 'ATP-UART Start GSM' notification to the ATP-UART interface. */ return (rvf_send_msg (gbl_atp_uart_ctrl_blk_p->addr_id, \ start_gsm_p)); } /********************* End of atp_uart_start_gsm function *********************/