diff options
Diffstat (limited to 'src/lib/uart8250mem.c')
| -rw-r--r-- | src/lib/uart8250mem.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/src/lib/uart8250mem.c b/src/lib/uart8250mem.c new file mode 100644 index 0000000000..918308ecdf --- /dev/null +++ b/src/lib/uart8250mem.c @@ -0,0 +1,139 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2003 Eric Biederman + * Copyright (C) 2006-2010 coresystems GmbH + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <arch/io.h> +#include <uart8250.h> +#include <pc80/mc146818rtc.h> +#if CONFIG_USE_OPTION_TABLE +#include "option_table.h" +#endif +#if !defined(__SMM__) && !defined(__PRE_RAM__) +#include <device/device.h> +#endif + +/* Should support 8250, 16450, 16550, 16550A type UARTs */ + +static inline int uart8250_mem_can_tx_byte(unsigned base_port) +{ + return read8(base_port + UART_LSR) & UART_MSR_DSR; +} + +static inline void uart8250_mem_wait_to_tx_byte(unsigned base_port) +{ + while(!uart8250_mem_can_tx_byte(base_port)) + ; +} + +static inline void uart8250_mem_wait_until_sent(unsigned base_port) +{ + while(!(read8(base_port + UART_LSR) & UART_LSR_TEMT)) + ; +} + +void uart8250_mem_tx_byte(unsigned base_port, unsigned char data) +{ + uart8250_mem_wait_to_tx_byte(base_port); + write8(base_port + UART_TBR, data); + /* Make certain the data clears the FIFOs */ + uart8250_mem_wait_until_sent(base_port); +} + +int uart8250_mem_can_rx_byte(unsigned base_port) +{ + return read8(base_port + UART_LSR) & UART_LSR_DR; +} + +unsigned char uart8250_mem_rx_byte(unsigned base_port) +{ + while(!uart8250_mem_can_rx_byte(base_port)) + ; + return read8(base_port + UART_RBR); +} + +void uart8250_mem_init(unsigned base_port, unsigned divisor) +{ + /* Disable interrupts */ + write8(base_port + UART_IER, 0x0); + /* Enable FIFOs */ + write8(base_port + UART_FCR, UART_FCR_FIFO_EN); + + /* Assert DTR and RTS so the other end is happy */ + write8(base_port + UART_MCR, UART_MCR_DTR | UART_MCR_RTS); + + /* DLAB on */ + write8(base_port + UART_LCR, UART_LCR_DLAB | CONFIG_TTYS0_LCS); + + /* Set Baud Rate Divisor. 12 ==> 115200 Baud */ + write8(base_port + UART_DLL, divisor & 0xFF); + write8(base_port + UART_DLM, (divisor >> 8) & 0xFF); + + /* Set to 3 for 8N1 */ + write8(base_port + UART_LCR, CONFIG_TTYS0_LCS); +} + +u32 uart_mem_init(void) +{ + unsigned uart_baud = CONFIG_TTYS0_BAUD; + u32 uart_bar = 0; + unsigned div; + + /* find out the correct baud rate */ +#if !defined(__SMM__) && CONFIG_USE_OPTION_TABLE + static const unsigned baud[8] = { 115200, 57600, 38400, 19200, 9600, 4800, 2400, 1200 }; + unsigned b_index = 0; +#if defined(__PRE_RAM__) + b_index = read_option(CMOS_VSTART_baud_rate, CMOS_VLEN_baud_rate, 0); + b_index &= 7; + uart_baud = baud[b_index]; +#else + if (get_option(&b_index, "baud_rate") == 0) { + uart_baud = baud[b_index]; + } +#endif +#endif + + /* Now find the UART base address and calculate the divisor */ +#if CONFIG_DRIVERS_OXFORD_OXPCIE + +#if defined(MORE_TESTING) && !defined(__SMM__) && !defined(__PRE_RAM__) + device_t dev = dev_find_device(0x1415, 0xc158, NULL); + + if (dev) { + struct resource *res = find_resource(dev, 0x10); + + if (res) { + uart_bar = res->base + 0x1000; // for 1st UART + // uart_bar = res->base + 0x2000; // for 2nd UART + } + } + + if (!uart_bar) +#endif + uart_bar = CONFIG_OXFORD_OXPCIE_BASE_ADDRESS + 0x1000; // 1st UART + // uart_bar = CONFIG_OXFORD_OXPCIE_BASE_ADDRESS + 0x2000; // 2nd UART + + div = 4000000 / uart_baud; +#endif + + if (uart_bar) + uart8250_mem_init(uart_bar, div); + + return uart_bar; +} |