/*
* Copyright (c) 2013 embedded brains GmbH. All rights reserved.
*
* embedded brains GmbH
* Dornierstr. 4
* 82178 Puchheim
* Germany
* <info@embedded-brains.de>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
#include <bsp/zynq-uart.h>
#include <bsp/zynq-uart-regs.h>
#include <libchip/sersupp.h>
static volatile zynq_uart *zynq_uart_get_regs(int minor)
{
const console_tbl *ct = Console_Port_Tbl != NULL ?
Console_Port_Tbl[minor] : &Console_Configuration_Ports[minor];
return (volatile zynq_uart *) ct->ulCtrlPort1;
}
/*
* Make weak and let the user override.
*/
uint32_t zynq_uart_input_clock(void) __attribute__ ((weak));
uint32_t zynq_uart_input_clock(void)
{
return 100000000UL;
}
static int zynq_cal_baud_rate(uint32_t baudrate,
uint32_t* brgr,
uint32_t* bauddiv,
uint32_t modereg)
{
uint32_t brgr_value; /* Calculated value for baud rate generator */
uint32_t calcbaudrate; /* Calculated baud rate */
uint32_t bauderror; /* Diff between calculated and requested baud rate */
uint32_t best_error = 0xFFFFFFFF;
uint32_t percenterror;
uint32_t bdiv;
uint32_t inputclk = zynq_uart_input_clock();
/*
* Make sure the baud rate is not impossilby large.
* Fastest possible baud rate is Input Clock / 2.
*/
if ((baudrate * 2) > inputclk) {
return -1;
}
/*
* Check whether the input clock is divided by 8
*/
if(modereg & ZYNQ_UART_MODE_CLKS) {
inputclk = inputclk / 8;
}
/*
* Determine the Baud divider. It can be 4to 254.
* Loop through all possible combinations
*/
for (bdiv = 4; bdiv < 255; bdiv++) {
/*
* Calculate the value for BRGR register
*/
brgr_value = inputclk / (baudrate * (bdiv + 1));
/*
* Calculate the baud rate from the BRGR value
*/
calcbaudrate = inputclk/ (brgr_value * (bdiv + 1));
/*
* Avoid unsigned integer underflow
*/
if (baudrate > calcbaudrate) {
bauderror = baudrate - calcbaudrate;
}
else {
bauderror = calcbaudrate - baudrate;
}
/*
* Find the calculated baud rate closest to requested baud rate.
*/
if (best_error > bauderror) {
*brgr = brgr_value;
*bauddiv = bdiv;
best_error = bauderror;
}
}
/*
* Make sure the best error is not too large.
*/
percenterror = (best_error * 100) / baudrate;
#define XUARTPS_MAX_BAUD_ERROR_RATE 3 /* max % error allowed */
if (XUARTPS_MAX_BAUD_ERROR_RATE < percenterror) {
return -1;
}
return 0;
}
static void zynq_uart_initialize(int minor)
{
volatile zynq_uart *regs = zynq_uart_get_regs(minor);
uint32_t brgr = 0x3e;
uint32_t bauddiv = 0x6;
zynq_cal_baud_rate(115200, &brgr, &bauddiv, regs->mode);
regs->control &= ~(ZYNQ_UART_CONTROL_RXEN | ZYNQ_UART_CONTROL_TXEN);
regs->control = ZYNQ_UART_CONTROL_RXDIS
| ZYNQ_UART_CONTROL_TXDIS
| ZYNQ_UART_CONTROL_RXRES
| ZYNQ_UART_CONTROL_TXRES;
regs->mode = ZYNQ_UART_MODE_CHMODE(ZYNQ_UART_MODE_CHMODE_NORMAL)
| ZYNQ_UART_MODE_PAR(ZYNQ_UART_MODE_PAR_NONE)
| ZYNQ_UART_MODE_CHRL(ZYNQ_UART_MODE_CHRL_8);
regs->baud_rate_gen = ZYNQ_UART_BAUD_RATE_GEN_CD(brgr);
regs->baud_rate_div = ZYNQ_UART_BAUD_RATE_DIV_BDIV(bauddiv);
regs->rx_fifo_trg_lvl = ZYNQ_UART_RX_FIFO_TRG_LVL_RTRIG(0);
regs->rx_timeout = ZYNQ_UART_RX_TIMEOUT_RTO(0);
regs->control = ZYNQ_UART_CONTROL_RXEN
| ZYNQ_UART_CONTROL_TXEN
| ZYNQ_UART_CONTROL_RSTTO;
}
static int zynq_uart_first_open(int major, int minor, void *arg)
{
rtems_libio_open_close_args_t *oc = (rtems_libio_open_close_args_t *) arg;
struct rtems_termios_tty *tty = (struct rtems_termios_tty *) oc->iop->data1;
console_data *cd = &Console_Port_Data[minor];
const console_tbl *ct = Console_Port_Tbl[minor];
cd->termios_data = tty;
rtems_termios_set_initial_baud(tty, (rtems_termios_baud_t) ct->pDeviceParams);
return 0;
}
static int zynq_uart_last_close(int major, int minor, void *arg)
{
return 0;
}
static int zynq_uart_read_polled(int minor)
{
volatile zynq_uart *regs = zynq_uart_get_regs(minor);
if ((regs->channel_sts & ZYNQ_UART_CHANNEL_STS_REMPTY) != 0) {
return -1;
} else {
return ZYNQ_UART_TX_RX_FIFO_FIFO_GET(regs->tx_rx_fifo);
}
}
static void zynq_uart_write_polled(int minor, char c)
{
volatile zynq_uart *regs = zynq_uart_get_regs(minor);
while ((regs->channel_sts & ZYNQ_UART_CHANNEL_STS_TFUL) != 0) {
/* Wait */
}
regs->tx_rx_fifo = ZYNQ_UART_TX_RX_FIFO_FIFO(c);
}
static ssize_t zynq_uart_write_support_polled(
int minor,
const char *s,
size_t n
)
{
ssize_t i = 0;
for (i = 0; i < n; ++i) {
zynq_uart_write_polled(minor, s[i]);
}
return n;
}
static int zynq_uart_set_attribues(int minor, const struct termios *term)
{
#if 0
volatile zynq_uart *regs = zynq_uart_get_regs(minor);
uint32_t brgr = 0;
uint32_t bauddiv = 0;
int rc;
rc = zynq_cal_baud_rate(115200, &brgr, &bauddiv, regs->mode);
if (rc != 0)
return rc;
regs->control &= ~(ZYNQ_UART_CONTROL_RXEN | ZYNQ_UART_CONTROL_TXEN);
regs->baud_rate_gen = ZYNQ_UART_BAUD_RATE_GEN_CD(brgr);
regs->baud_rate_div = ZYNQ_UART_BAUD_RATE_DIV_BDIV(bauddiv);
regs->control |= ZYNQ_UART_CONTROL_RXEN | ZYNQ_UART_CONTROL_TXEN;
return 0;
#else
return -1;
#endif
}
const console_fns zynq_uart_fns = {
.deviceProbe = libchip_serial_default_probe,
.deviceFirstOpen = zynq_uart_first_open,
.deviceLastClose = zynq_uart_last_close,
.deviceRead = zynq_uart_read_polled,
.deviceWrite = zynq_uart_write_support_polled,
.deviceInitialize = zynq_uart_initialize,
.deviceWritePolled = zynq_uart_write_polled,
.deviceSetAttributes = zynq_uart_set_attribues,
.deviceOutputUsesInterrupts = false
};
