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/*
* (C) Copyright 2003
*
* Pantelis Antoniou <panto@intracom.gr>
* Intracom S.A.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <watchdog.h>
#include <serial.h>
#include <linux/compiler.h>
DECLARE_GLOBAL_DATA_PTR;
/**************************************************************/
/* convienient macros */
#define MAX3100_SPI_RXD() (MAX3100_SPI_RXD_PORT & MAX3100_SPI_RXD_BIT)
#define MAX3100_SPI_TXD(x) \
do { \
if (x) \
MAX3100_SPI_TXD_PORT |= MAX3100_SPI_TXD_BIT; \
else \
MAX3100_SPI_TXD_PORT &= ~MAX3100_SPI_TXD_BIT; \
} while(0)
#define MAX3100_SPI_CLK(x) \
do { \
if (x) \
MAX3100_SPI_CLK_PORT |= MAX3100_SPI_CLK_BIT; \
else \
MAX3100_SPI_CLK_PORT &= ~MAX3100_SPI_CLK_BIT; \
} while(0)
#define MAX3100_SPI_CLK_TOGGLE() (MAX3100_SPI_CLK_PORT ^= MAX3100_SPI_CLK_BIT)
#define MAX3100_CS(x) \
do { \
if (x) \
MAX3100_CS_PORT |= MAX3100_CS_BIT; \
else \
MAX3100_CS_PORT &= ~MAX3100_CS_BIT; \
} while(0)
/**************************************************************/
/* MAX3100 definitions */
#define MAX3100_WC (3 << 14) /* write configuration */
#define MAX3100_RC (1 << 14) /* read configuration */
#define MAX3100_WD (2 << 14) /* write data */
#define MAX3100_RD (0 << 14) /* read data */
/* configuration register bits */
#define MAX3100_FEN (1 << 13) /* FIFO enable */
#define MAX3100_SHDN (1 << 12) /* shutdown bit */
#define MAX3100_TM (1 << 11) /* T bit irq mask */
#define MAX3100_RM (1 << 10) /* R bit irq mask */
#define MAX3100_PM (1 << 9) /* P bit irq mask */
#define MAX3100_RAM (1 << 8) /* mask for RA/FE bit */
#define MAX3100_IR (1 << 7) /* IRDA timing mode */
#define MAX3100_ST (1 << 6) /* transmit stop bit */
#define MAX3100_PE (1 << 5) /* parity enable bit */
#define MAX3100_L (1 << 4) /* Length bit */
#define MAX3100_B_MASK (0x000F) /* baud rate bits mask */
#define MAX3100_B(x) ((x) & 0x000F) /* baud rate select bits */
/* data register bits (write) */
#define MAX3100_TE (1 << 10) /* transmit enable bit (active low) */
#define MAX3100_RTS (1 << 9) /* request-to-send bit (inverted ~RTS pin) */
/* data register bits (read) */
#define MAX3100_RA (1 << 10) /* receiver activity when in shutdown mode */
#define MAX3100_FE (1 << 10) /* framing error when in normal mode */
#define MAX3100_CTS (1 << 9) /* clear-to-send bit (inverted ~CTS pin) */
/* data register bits (both directions) */
#define MAX3100_R (1 << 15) /* receive bit */
#define MAX3100_T (1 << 14) /* transmit bit */
#define MAX3100_P (1 << 8) /* parity bit */
#define MAX3100_D_MASK 0x00FF /* data bits mask */
#define MAX3100_D(x) ((x) & 0x00FF) /* data bits */
/* these definitions are valid only for fOSC = 3.6864MHz */
#define MAX3100_B_230400 MAX3100_B(0)
#define MAX3100_B_115200 MAX3100_B(1)
#define MAX3100_B_57600 MAX3100_B(2)
#define MAX3100_B_38400 MAX3100_B(9)
#define MAX3100_B_19200 MAX3100_B(10)
#define MAX3100_B_9600 MAX3100_B(11)
#define MAX3100_B_4800 MAX3100_B(12)
#define MAX3100_B_2400 MAX3100_B(13)
#define MAX3100_B_1200 MAX3100_B(14)
#define MAX3100_B_600 MAX3100_B(15)
/**************************************************************/
static inline unsigned int max3100_transfer(unsigned int val)
{
unsigned int rx;
int b;
MAX3100_SPI_CLK(0);
MAX3100_CS(0);
rx = 0; b = 16;
while (--b >= 0) {
MAX3100_SPI_TXD(val & 0x8000);
val <<= 1;
MAX3100_SPI_CLK_TOGGLE();
udelay(1);
rx <<= 1;
if (MAX3100_SPI_RXD())
rx |= 1;
MAX3100_SPI_CLK_TOGGLE();
udelay(1);
}
MAX3100_SPI_CLK(1);
MAX3100_CS(1);
return rx;
}
/**************************************************************/
/* must be power of 2 */
#define RXFIFO_SZ 16
static int rxfifo_cnt;
static int rxfifo_in;
static int rxfifo_out;
static unsigned char rxfifo_buf[16];
static void max3100_serial_putc_raw(int c)
{
unsigned int rx;
while (((rx = max3100_transfer(MAX3100_RC)) & MAX3100_T) == 0)
WATCHDOG_RESET();
rx = max3100_transfer(MAX3100_WD | (c & 0xff));
if ((rx & MAX3100_RD) != 0 && rxfifo_cnt < RXFIFO_SZ) {
rxfifo_cnt++;
rxfifo_buf[rxfifo_in++] = rx & 0xff;
rxfifo_in &= RXFIFO_SZ - 1;
}
}
static int max3100_serial_getc(void)
{
int c;
unsigned int rx;
while (rxfifo_cnt == 0) {
rx = max3100_transfer(MAX3100_RD);
if ((rx & MAX3100_R) != 0) {
do {
rxfifo_cnt++;
rxfifo_buf[rxfifo_in++] = rx & 0xff;
rxfifo_in &= RXFIFO_SZ - 1;
if (rxfifo_cnt >= RXFIFO_SZ)
break;
} while (((rx = max3100_transfer(MAX3100_RD)) & MAX3100_R) != 0);
}
WATCHDOG_RESET();
}
rxfifo_cnt--;
c = rxfifo_buf[rxfifo_out++];
rxfifo_out &= RXFIFO_SZ - 1;
return c;
}
static int max3100_serial_tstc(void)
{
unsigned int rx;
if (rxfifo_cnt > 0)
return 1;
rx = max3100_transfer(MAX3100_RD);
if ((rx & MAX3100_R) == 0)
return 0;
do {
rxfifo_cnt++;
rxfifo_buf[rxfifo_in++] = rx & 0xff;
rxfifo_in &= RXFIFO_SZ - 1;
if (rxfifo_cnt >= RXFIFO_SZ)
break;
} while (((rx = max3100_transfer(MAX3100_RD)) & MAX3100_R) != 0);
return 1;
}
static int max3100_serial_init(void)
{
unsigned int wconf, rconf;
int i;
wconf = 0;
/* Set baud rate */
switch (gd->baudrate) {
case 1200:
wconf = MAX3100_B_1200;
break;
case 2400:
wconf = MAX3100_B_2400;
break;
case 4800:
wconf = MAX3100_B_4800;
break;
case 9600:
wconf = MAX3100_B_9600;
break;
case 19200:
wconf = MAX3100_B_19200;
break;
case 38400:
wconf = MAX3100_B_38400;
break;
case 57600:
wconf = MAX3100_B_57600;
break;
default:
case 115200:
wconf = MAX3100_B_115200;
break;
case 230400:
wconf = MAX3100_B_230400;
break;
}
/* try for 10ms, with a 100us gap */
for (i = 0; i < 10000; i += 100) {
max3100_transfer(MAX3100_WC | wconf);
rconf = max3100_transfer(MAX3100_RC) & 0x3fff;
if (rconf == wconf)
break;
udelay(100);
}
rxfifo_in = rxfifo_out = rxfifo_cnt = 0;
return (0);
}
static void max3100_serial_putc(const char c)
{
if (c == '\n')
max3100_serial_putc_raw('\r');
max3100_serial_putc_raw(c);
}
static void max3100_serial_puts(const char *s)
{
while (*s)
max3100_serial_putc_raw(*s++);
}
static void max3100_serial_setbrg(void)
{
}
static struct serial_device max3100_serial_drv = {
.name = "max3100_serial",
.start = max3100_serial_init,
.stop = NULL,
.setbrg = max3100_serial_setbrg,
.putc = max3100_serial_putc,
.puts = max3100_serial_puts,
.getc = max3100_serial_getc,
.tstc = max3100_serial_tstc,
};
void max3100_serial_initialize(void)
{
serial_register(&max3100_serial_drv);
}
__weak struct serial_device *default_serial_console(void)
{
return &max3100_serial_drv;
}