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SERCOMM: make sure to disable IRQ/FIQ to avoid race conditions

This commit is contained in:
Harald Welte 2010-02-28 17:37:47 +01:00
parent 80409074d9
commit f3685191f6
2 changed files with 31 additions and 1 deletions
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21
src/target/firmware/comm/sercomm.c
View File

@ -30,10 +30,14 @@
#endif
#include <osmocore/msgb.h>
#include <sercomm.h>
#define local_irq_save(x)
#define local_fiq_disable()
#define local_irq_restore(x)
#else
#include <debug.h>
#include <linuxlist.h>
#include <asm/system.h>
#include <comm/msgb.h>
#include <comm/sercomm.h>
@ -89,13 +93,20 @@ int sercomm_initialized(void)
/* user interface for transmitting messages for a given DLCI */
void sercomm_sendmsg(uint8_t dlci, struct msgb *msg)
{
unsigned long flags;
uint8_t *hdr;
/* prepend address + control octet */
hdr = msgb_push(msg, 2);
hdr[0] = dlci;
hdr[1] = HDLC_C_UI;
/* This functiion can be called from any context: FIQ, IRQ
* and supervisor context. Proper locking is important! */
local_irq_save(flags);
local_fiq_disable();
msgb_enqueue(&sercomm.tx.dlci_queues[dlci], msg);
local_irq_restore(flags);
#ifndef HOST_BUILD
/* tell UART that we have something to send */
@ -119,6 +130,9 @@ unsigned int sercomm_tx_queue_depth(uint8_t dlci)
/* fetch one octet of to-be-transmitted serial data */
int sercomm_drv_pull(uint8_t *ch)
{
/* we are always called from interrupt context in this function,
* which means that any data structures we use need to be for
* our exclusive access */
if (!sercomm.tx.msg) {
unsigned int i;
/* dequeue a new message from the queues */
@ -187,10 +201,14 @@ int sercomm_drv_rx_char(uint8_t ch)
{
uint8_t *ptr;
/* we are always called from interrupt context in this function,
* which means that any data structures we use need to be for
* our exclusive access */
if (!sercomm.rx.msg)
sercomm.rx.msg = sercomm_alloc_msgb(SERCOMM_RX_MSG_SIZE);
if (msgb_tailroom(sercomm.rx.msg) == 0) {
cons_puts("sercomm_drv_rx_char() overflow!\n");
msgb_free(sercomm.rx.msg);
sercomm.rx.msg = sercomm_alloc_msgb(SERCOMM_RX_MSG_SIZE);
sercomm.rx.state = RX_ST_WAIT_START;
@ -200,7 +218,7 @@ int sercomm_drv_rx_char(uint8_t ch)
switch (sercomm.rx.state) {
case RX_ST_WAIT_START:
if (ch != HDLC_FLAG)
return 0;
break;
sercomm.rx.state = RX_ST_ADDR;
break;
case RX_ST_ADDR:
@ -240,5 +258,6 @@ int sercomm_drv_rx_char(uint8_t ch)
sercomm.rx.state = RX_ST_DATA;
break;
}
return 1;
}

11
src/target/firmware/comm/sercomm_cons.c
View File

@ -24,6 +24,8 @@
#include <errno.h>
#include <string.h>
#include <asm/system.h>
#include <calypso/uart.h>
#include <console.h>
@ -50,6 +52,7 @@ static void raw_puts(const char *s)
int sercomm_puts(const char *s)
{
unsigned long flags;
const int len = strlen(s) + 1;
unsigned int bytes_left = len;
@ -59,6 +62,12 @@ int sercomm_puts(const char *s)
return len - 1;
}
/* This function is called from any context: Supervisor, IRQ, FIQ, ...
* as such, we need to ensure re-entrant calls are either supported or
* avoided. */
local_irq_save(flags);
local_fiq_disable();
while (bytes_left > 0) {
unsigned int write_num, space_left, flush;
uint8_t *data;
@ -110,6 +119,8 @@ int sercomm_puts(const char *s)
}
}
local_irq_restore(flags);
return len - 1;
}