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use rx and tx queues for uart
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@malvira
malvira committed Nov 18, 2012
1 parent 731272c commit d12df2e
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Showing 5 changed files with 235 additions and 114 deletions.
35 changes: 33 additions & 2 deletions lib/include/uart.h
View file
Expand Up @@ -156,14 +156,45 @@ void uart_init(volatile struct UART_struct * uart, uint32_t baud);
void uart_setbaud(volatile struct UART_struct * uart, uint32_t baud);
void uart_flowctl(volatile struct UART_struct * uart, uint8_t on);

extern volatile uint32_t u1_head, u1_tail;

/* The mc1322x has a 32 byte hardware FIFO for transmitted characters.
* Currently it is always filled from a larger RAM buffer. It would be
* possible to eliminate that overhead by filling directly from a chain
* of data buffer pointers, but printf's would be not so easy.
*/
#define UART1_TX_BUFFERSIZE 1024
extern volatile uint32_t u1_tx_head, u1_tx_tail;
void uart1_putc(char c);

/* The mc1322x has a 32 byte hardware FIFO for received characters.
* If a larger rx buffersize is specified the FIFO will be extended into RAM.
* RAM transfers will occur on interrupt when the FIFO is nearly full.
* If a smaller buffersize is specified hardware flow control will be
* initiated at that FIFO level.
* Set to 32 for no flow control or RAM buffer.
*/
#define UART1_RX_BUFFERSIZE 128
#if UART1_RX_BUFFERSIZE > 32
extern volatile uint32_t u1_rx_head, u1_rx_tail;
#define uart1_can_get() ((u1_rx_head!=u1_rx_tail) || (*UART1_URXCON > 0))
#else
#define uart1_can_get() (*UART1_URXCON > 0)
#endif
uint8_t uart1_getc(void);

extern volatile uint32_t u2_head, u2_tail;

#define UART2_TX_BUFFERSIZE 1024
extern volatile uint32_t u2_tx_head, u2_tx_tail;
void uart2_putc(char c);

#define UART2_RX_BUFFERSIZE 128
#if UART2_RX_BUFFERSIZE > 32
extern volatile uint32_t u2_rx_head, u2_rx_tail;
#define uart2_can_get() ((u2_rx_head!=u2_rx_tail) || (*UART2_URXCON > 0))
#else
#define uart2_can_get() (*UART2_URXCON > 0)
#endif
uint8_t uart2_getc(void);

#endif

43 changes: 32 additions & 11 deletions lib/uart.c
View file
Expand Up @@ -50,18 +50,14 @@ void uart_setbaud(volatile struct UART_struct * uart, uint32_t baud) {
inc = (inc + 5) / 10;

/* UART must be disabled to set the baudrate */
uart->CONbits = (struct UART_CON) {
.TXE = 0,
.RXE = 0,
};
uart->CONbits.TXE = 0;
uart->CONbits.RXE = 0;

uart->BR = ( (uint16_t)inc << 16 ) | MOD;

uart->CONbits = (struct UART_CON) {
.XTIM = 0,
.TXE = 1,
.RXE = 1,
};
uart->CONbits.XTIM = 0;
uart->CONbits.TXE = 1;
uart->CONbits.RXE = 1;
}

void uart_flowctl(volatile struct UART_struct * uart, uint8_t on) {
Expand Down Expand Up @@ -117,6 +113,7 @@ void uart_init(volatile struct UART_struct * uart, uint32_t baud) {
.TXE = 1,
.RXE = 1,
};

/* interrupt when there are this number or more bytes free in the TX buffer*/
uart->TXCON = 16;

Expand All @@ -129,7 +126,19 @@ void uart_init(volatile struct UART_struct * uart, uint32_t baud) {
GPIO->FUNC_SEL.U1TX = 1;
GPIO->FUNC_SEL.U1RX = 1;

u1_head = 0; u1_tail = 0;
#if UART1_RX_BUFFERSIZE > 32
*UART1_UCON = (1 << 0) | (1 << 1) ; /* enable receive, transmit, and both interrupts */
*UART1_URXCON = 30; /* interrupt when fifo is nearly full */
u1_rx_head = 0; u1_rx_tail = 0;
#elif UART1_RX_BUFFERSIZE < 32 /* enable receive, transmit, flow control, disable rx interrupt */
*UART1_UCON = (1 << 0) | (1 << 1) | (1 << 12) | (1 << 14);
*UART1_UCTS = UART1_RX_BUFFERSIZE; /* drop cts when tx buffer at trigger level */
*GPIO_FUNC_SEL1 = ( (0x01 << (0*2)) | (0x01 << (1*2)) ); /* set GPIO17-16 to UART1 CTS and RTS */
#else
*UART1_UCON = (1 << 0) | (1 << 1) | (1 << 14); /* enable receive, transmit, disable rx interrupt */
#endif

u1_tx_head = 0; u1_tx_tail = 0;

/* tx and rx interrupts are enabled in the UART by default */
/* see status register bits 13 and 14 */
Expand All @@ -146,7 +155,19 @@ void uart_init(volatile struct UART_struct * uart, uint32_t baud) {
GPIO->FUNC_SEL.U2TX = 1;
GPIO->FUNC_SEL.U2RX = 1;

u2_head = 0; u2_tail = 0;
#if UART2_RX_BUFFERSIZE > 32
*UART2_UCON = (1 << 0) | (1 << 1) ; /* enable receive, transmit, and both interrupts */
*UART2_URXCON = 30; /* interrupt when fifo is nearly full */
u2_rx_head = 0; u2_rx_tail = 0;
#elif UART2_RX_BUFFERSIZE < 32 /* enable receive, transmit, disable flow control, disable rx interrupt */
*UART2_UCON = (1 << 0) | (1 << 1) | (0 << 12) | (1 << 14);
*UART2_UCTS = UART2_RX_BUFFERSIZE; /* drop cts when tx buffer at trigger level */
*GPIO_FUNC_SEL1 = ( (0x01 << (0*2)) | (0x01 << (1*2)) ); /* set GPIO17-16 to UART2 CTS and RTS */
#else
*UART2_UCON = (1 << 0) | (1 << 1) | (1 << 14); /* enable receive, transmit, disable rx interrupt */
#endif

u2_tx_head = 0; u2_tx_tail = 0;

enable_irq(UART2);
}
Expand Down
104 changes: 86 additions & 18 deletions lib/uart1.c
View file
Expand Up @@ -28,51 +28,119 @@
* SUCH DAMAGE.
*
* This file is part of libmc1322x: see http://mc1322x.devl.org
* for details.
* for details.
*
*
*/

#include <mc1322x.h>
#include <stdint.h>

volatile char u1_tx_buf[64];
volatile uint32_t u1_head, u1_tail;
volatile char u1_tx_buf[UART1_TX_BUFFERSIZE];
volatile uint32_t u1_tx_head, u1_tx_tail;

#if UART1_RX_BUFFERSIZE > 32
volatile char u1_rx_buf[UART1_RX_BUFFERSIZE-32];
volatile uint32_t u1_rx_head, u1_rx_tail;
#endif

void uart1_isr(void) {
while( *UART1_UTXCON != 0 ) {
if (u1_head == u1_tail) {

#if UART1_RX_BUFFERSIZE > 32
if (*UART1_USTAT & ( 1 << 6)) { //receive interrupt
while( *UART1_URXCON != 0 ) { //flush the hardware fifo into the software buffer
uint32_t u1_rx_tail_next;
u1_rx_tail_next = u1_rx_tail+1;
if (u1_rx_tail_next >= sizeof(u1_rx_buf))
u1_rx_tail_next = 0;
if (u1_rx_head != u1_rx_tail_next) {
u1_rx_buf[u1_rx_tail]= *UART1_UDATA;
u1_rx_tail = u1_rx_tail_next;
} else { //buffer is full, flush the fifo
while (*UART1_URXCON !=0) { if (*UART1_UDATA) { } }
}
}
return;
}
#endif

while( *UART1_UTXCON != 0 ) {
if (u1_tx_head == u1_tx_tail) {
#if UART1_RX_BUFFERSIZE > 32
*UART1_UCON |= (1 << 13); /*disable tx interrupt */
#else
disable_irq(UART1);
#endif
return;
}
*UART1_UDATA = u1_tx_buf[u1_tail];
u1_tail++;
if (u1_tail >= sizeof(u1_tx_buf))
u1_tail = 0;

*UART1_UDATA = u1_tx_buf[u1_tx_tail];
u1_tx_tail++;
if (u1_tx_tail >= sizeof(u1_tx_buf))
u1_tx_tail = 0;
}
}

void uart1_putc(char c) {
/* disable UART1 since */
/* UART1 isr modifies u1_head and u1_tail */
disable_irq(UART1);
/* UART1 isr modifies u1_tx_head and u1_tx_tail */
#if UART1_RX_BUFFERSIZE > 32
*UART1_UCON |= (1 << 13); /*disable tx interrupt */
#else
disable_irq(UART1);
#endif

if( (u1_head == u1_tail) &&
if( (u1_tx_head == u1_tx_tail) &&
(*UART1_UTXCON != 0)) {
*UART1_UDATA = c;
} else {
u1_tx_buf[u1_head] = c;
u1_head += 1;
if (u1_head >= sizeof(u1_tx_buf))
u1_head = 0;
if (u1_head == u1_tail) { /* drop chars when no room */
if (u1_head) { u1_head -=1; } else { u1_head = sizeof(u1_tx_buf); }
u1_tx_buf[u1_tx_head] = c;
u1_tx_head += 1;
if (u1_tx_head >= sizeof(u1_tx_buf))
u1_tx_head = 0;
if (u1_tx_head == u1_tx_tail) { /* drop chars when no room */
#if UART1_DROP_CHARS
if (u1_tx_head) { u1_tx_head -=1; } else { u1_tx_head = sizeof(u1_tx_buf); }
#else
{
uint32_t u1_tx_tail_save=u1_tx_tail;
/* Back up head to show buffer not empty, and enable tx interrupt */
u1_tx_head--;
#if UART1_RX_BUFFERSIZE > 32
*UART1_UCON &= ~(1 << 13); /*enable tx interrupt */
#else
enable_irq(UART1);
#endif
/* Tail will change after one character goes out */
while (u1_tx_tail_save == u1_tx_tail) ;
/* Restore head to character we just stuffed */
u1_tx_head++;
return;
}
#endif /* UART1_DROP_CHARS */
}

#if UART1_RX_BUFFERSIZE > 32
*UART1_UCON &= ~(1 << 13); /*enable tx interrupt */
#else
enable_irq(UART1);
#endif

}
}

uint8_t uart1_getc(void) {
#if UART1_RX_BUFFERSIZE > 32
/* First pull from the ram buffer */
uint8_t c=0;
if (u1_rx_head != u1_rx_tail) {
c = u1_rx_buf[u1_rx_head++];
if (u1_rx_head >= sizeof(u1_rx_buf))
u1_rx_head=0;
return c;
}
#endif
/* Then pull from the hardware fifo */
while(uart1_can_get() == 0) { continue; }
return *UART1_UDATA;
}
100 changes: 84 additions & 16 deletions lib/uart2.c
View file
Expand Up @@ -36,43 +36,111 @@
#include <mc1322x.h>
#include <stdint.h>

volatile char u2_tx_buf[64];
volatile uint32_t u2_head, u2_tail;
volatile char u2_tx_buf[UART2_TX_BUFFERSIZE];
volatile uint32_t u2_tx_head, u2_tx_tail;

#if UART2_RX_BUFFERSIZE > 32
volatile char u2_rx_buf[UART2_RX_BUFFERSIZE-32];
volatile uint32_t u2_rx_head, u2_rx_tail;
#endif

void uart2_isr(void) {

#if UART2_RX_BUFFERSIZE > 32
if (*UART2_USTAT & ( 1 << 6)) { //receive interrupt
while( *UART2_URXCON != 0 ) { //flush the hardware fifo into the software buffer
uint32_t u2_rx_tail_next;
u2_rx_tail_next = u2_rx_tail+1;
if (u2_rx_tail_next >= sizeof(u2_rx_buf))
u2_rx_tail_next = 0;
if (u2_rx_head != u2_rx_tail_next) {
u2_rx_buf[u2_rx_tail]= *UART2_UDATA;
u2_rx_tail = u2_rx_tail_next;
} else { //buffer is full, flush the fifo
while (*UART2_URXCON !=0) { if (*UART2_UDATA) { } }
}
}
return;
}
#endif

while( *UART2_UTXCON != 0 ) {
if (u2_head == u2_tail) {
if (u2_tx_head == u2_tx_tail) {
#if UART2_RX_BUFFERSIZE > 32
*UART2_UCON |= (1 << 13); /*disable tx interrupt */
#else
disable_irq(UART2);
#endif
return;
}
*UART2_UDATA = u2_tx_buf[u2_tail];
u2_tail++;
if (u2_tail >= sizeof(u2_tx_buf))
u2_tail = 0;
*UART2_UDATA = u2_tx_buf[u2_tx_tail];
u2_tx_tail++;
if (u2_tx_tail >= sizeof(u2_tx_buf))
u2_tx_tail = 0;
}

}

void uart2_putc(char c) {
/* disable UART2 since */
/* UART2 isr modifies u2_head and u2_tail */
disable_irq(UART2);
/* UART2 isr modifies u2_tx_head and u2_tx_tail */
#if UART2_RX_BUFFERSIZE > 32
*UART2_UCON |= (1 << 13); /*disable tx interrupt */
#else
disable_irq(UART2);
#endif

if( (u2_head == u2_tail) &&
if( (u2_tx_head == u2_tx_tail) &&
(*UART2_UTXCON != 0)) {
*UART2_UDATA = c;
} else {
u2_tx_buf[u2_head] = c;
u2_head += 1;
if (u2_head >= sizeof(u2_tx_buf))
u2_head = 0;
if (u2_head == u2_tail) { /* drop chars when no room */
if (u2_head) { u2_head -=1; } else { u2_head = sizeof(u2_tx_buf); }
u2_tx_buf[u2_tx_head] = c;
u2_tx_head += 1;
if (u2_tx_head >= sizeof(u2_tx_buf))
u2_tx_head = 0;
if (u2_tx_head == u2_tx_tail) { /* drop chars when no room */
#if UART2_DROP_CHARS
if (u2_tx_head) { u2_tx_head -=1; } else { u2_tx_head = sizeof(u2_tx_buf); }
#else
{
uint32_t u2_tx_tail_save=u2_tx_tail;
/* Back up head to show buffer not empty, and enable tx interrupt */
u2_tx_head--;
#if UART2_RX_BUFFERSIZE > 32
*UART2_UCON &= ~(1 << 13); /*enable tx interrupt */
#else
enable_irq(UART2);
#endif
/* Tail will change after one character goes out */
while (u2_tx_tail_save == u2_tx_tail) ;
/* Restore head to character we just stuffed */
u2_tx_head++;
return;
}
#endif /* UART2_DROP_CHARS */
}

#if UART2_RX_BUFFERSIZE > 32
*UART2_UCON &= ~(1 << 13); /*enable tx interrupt */
#else
enable_irq(UART2);
#endif

}
}

uint8_t uart2_getc(void) {
#if UART2_RX_BUFFERSIZE > 32
/* First pull from the ram buffer */
uint8_t c=0;
if (u2_rx_head != u2_rx_tail) {
c = u2_rx_buf[u2_rx_head++];
if (u2_rx_head >= sizeof(u2_rx_buf))
u2_rx_head=0;
return c;
}
#endif
/* Then pull from the hardware fifo */
while(uart2_can_get() == 0) { continue; }
return *UART2_UDATA;
}

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