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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>
struct tegra210_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 lcr; // Line control register.
uint32_t mcr; // Modem control register.
uint32_t lsr; // Line status register.
uint32_t msr; // Modem status register.
} __packed;
static struct tegra210_uart * const uart_ptr =
(void *)CONFIG_CONSOLE_SERIAL_TEGRA210_UART_ADDRESS;
static void tegra210_uart_tx_flush(void);
static int tegra210_uart_tst_byte(void);
static void tegra210_uart_init(void)
{
// Use a hardcoded divisor for now.
const unsigned int divisor = 221;
const uint8_t line_config = UART8250_LCR_WLS_8; // 8n1
tegra210_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 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 tegra210_uart_tx_byte(unsigned char data)
{
while (!(read8(&uart_ptr->lsr) & UART8250_LSR_THRE));
write8(&uart_ptr->thr, data);
}
static void tegra210_uart_tx_flush(void)
{
while (!(read8(&uart_ptr->lsr) & UART8250_LSR_TEMT));
}
static unsigned char tegra210_uart_rx_byte(void)
{
if (!tegra210_uart_tst_byte())
return 0;
return read8(&uart_ptr->rbr);
}
static int tegra210_uart_tst_byte(void)
{
return (read8(&uart_ptr->lsr) & UART8250_LSR_DR) == UART8250_LSR_DR;
}
void uart_init(unsigned int idx)
{
tegra210_uart_init();
}
void uart_tx_byte(unsigned int idx, unsigned char data)
{
tegra210_uart_tx_byte(data);
}
void uart_tx_flush(unsigned int idx)
{
tegra210_uart_tx_flush();
}
unsigned char uart_rx_byte(unsigned int idx)
{
return tegra210_uart_rx_byte();
}
enum cb_err fill_lb_serial(struct lb_serial *serial)
{
serial->type = LB_SERIAL_TYPE_MEMORY_MAPPED;
serial->baseaddr = CONFIG_CONSOLE_SERIAL_TEGRA210_UART_ADDRESS;
serial->baud = get_uart_baudrate();
serial->regwidth = 4;
serial->input_hertz = uart_platform_refclk();
return CB_SUCCESS;
}
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