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/* SPDX-License-Identifier: GPL-2.0-only */
#include <device/mmio.h>
#include <boot/coreboot_tables.h>
#include <console/uart.h>
#include <drivers/uart/uart8250reg.h>
#include <stdint.h>
#include <soc/addressmap.h>
#include <soc/pll.h>
struct mtk_uart {
union {
uint32_t thr; /* Transmit holding register. */
uint32_t rbr; /* Receive buffer register. */
uint32_t dll; /* Divisor latch lsb. */
};
union {
uint32_t ier; /* Interrupt enable register. */
uint32_t dlm; /* Divisor latch msb. */
};
union {
uint32_t iir; /* Interrupt identification register. */
uint32_t fcr; /* FIFO control register. */
uint32_t efr; /* Enhanced feature register. */
};
uint32_t lcr; /* Line control register. */
union {
uint32_t mcr; /* Modem control register. */
uint32_t xn1; /* XON1 */
};
union {
uint32_t lsr; /* Line status register. */
uint32_t xn2; /* XON2 */
};
union {
uint32_t msr; /* Modem status register. */
uint32_t xf1; /* XOFF1 */
};
union {
uint32_t scr; /* Scratch register. */
uint32_t xf2; /* XOFF2 */
};
uint32_t autobaud_en; /* Enable auto baudrate. */
uint32_t highspeed; /* High speed UART. */
} __packed;
/* Peripheral Reset and Power Down registers */
struct mtk_peri_globalcon {
uint32_t rst0;
uint32_t rst1;
uint32_t pdn0_set;
uint32_t pdn1_set;
uint32_t pdn0_clr;
uint32_t pdn1_clr;
uint32_t pdn0_sta;
uint32_t pdn1_sta;
uint32_t pdn_md1_set;
uint32_t pdn_md2_set;
uint32_t pdn_md1_clr;
uint32_t pdn_md2_clr;
uint32_t pdn_md1_sta;
uint32_t pdn_md2_sta;
uint32_t pdn_md_mask;
} __packed;
static struct mtk_uart *const uart_ptr = (void *)UART0_BASE;
static void mtk_uart_tx_flush(void);
static int mtk_uart_tst_byte(void);
static void mtk_uart_init(void)
{
/* Use a hardcoded divisor for now. */
const unsigned int uartclk = UART_HZ;
const unsigned int baudrate = get_uart_baudrate();
const uint8_t line_config = UART8250_LCR_WLS_8; /* 8n1 */
unsigned int highspeed, quot, divisor, remainder;
if (baudrate <= 115200) {
highspeed = 0;
quot = 16;
} else {
highspeed = 2;
quot = 4;
}
/* Set divisor DLL and DLH */
divisor = uartclk / (quot * baudrate);
remainder = uartclk % (quot * baudrate);
if (remainder >= (quot / 2) * baudrate)
divisor += 1;
mtk_uart_tx_flush();
/* Disable interrupts. */
write8(&uart_ptr->ier, 0);
/* Force DTR and RTS to high. */
write8(&uart_ptr->mcr, UART8250_MCR_DTR | UART8250_MCR_RTS);
/* Set High speed UART register. */
write8(&uart_ptr->highspeed, highspeed);
/* Set line configuration, access divisor latches. */
write8(&uart_ptr->lcr, UART8250_LCR_DLAB | line_config);
/* Set the divisor. */
write8(&uart_ptr->dll, divisor & 0xff);
write8(&uart_ptr->dlm, (divisor >> 8) & 0xff);
/* Hide the divisor latches. */
write8(&uart_ptr->lcr, line_config);
/* Enable FIFOs, and clear receive and transmit. */
write8(&uart_ptr->fcr,
UART8250_FCR_FIFO_EN | UART8250_FCR_CLEAR_RCVR |
UART8250_FCR_CLEAR_XMIT);
}
static void mtk_uart_tx_byte(unsigned char data)
{
while (!(read8(&uart_ptr->lsr) & UART8250_LSR_THRE))
;
write8(&uart_ptr->thr, data);
}
static void mtk_uart_tx_flush(void)
{
while (!(read8(&uart_ptr->lsr) & UART8250_LSR_TEMT))
;
}
static unsigned char mtk_uart_rx_byte(void)
{
if (!mtk_uart_tst_byte())
return 0;
return read8(&uart_ptr->rbr);
}
static int mtk_uart_tst_byte(void)
{
return (read8(&uart_ptr->lsr) & UART8250_LSR_DR) == UART8250_LSR_DR;
}
void uart_init(unsigned int idx)
{
mtk_uart_init();
}
unsigned char uart_rx_byte(unsigned int idx)
{
return mtk_uart_rx_byte();
}
void uart_tx_byte(unsigned int idx, unsigned char data)
{
mtk_uart_tx_byte(data);
}
void uart_tx_flush(unsigned int idx)
{
mtk_uart_tx_flush();
}
enum cb_err fill_lb_serial(struct lb_serial *serial)
{
serial->type = LB_SERIAL_TYPE_MEMORY_MAPPED;
serial->baseaddr = UART0_BASE;
serial->baud = get_uart_baudrate();
serial->regwidth = 4;
serial->input_hertz = UART_HZ;
return CB_SUCCESS;
}
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