ti/am335x: Fix baudrate calculation
UART input clock is platform dependent. Also account for possible use of get_option() where baudrate is not compile-time constant. The hardware reference on BeagleBone is from a 48 MHz oscillator input. With pre-divisor of 16 we get same register values as in table 19-25. Change-Id: I89aee27c958f8618ce79a968ae7520a867e7e8a2 Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com> Reviewed-on: http://review.coreboot.org/5290 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
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@ -35,10 +35,10 @@
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#define LSR_TXFIFOE (1 << 5)
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/*
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* Initialise the serial port with the given baudrate. The settings
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* Initialise the serial port with the given baudrate divisor. The settings
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* are always 8 data bits, no parity, 1 stop bit, no start bits.
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*/
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static void am335x_uart_init_dev(void)
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static void am335x_uart_init(uint16_t div)
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{
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struct am335x_uart *uart = (struct am335x_uart *)
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CONFIG_CONSOLE_SERIAL_UART_ADDRESS;
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@ -107,24 +107,8 @@ static void am335x_uart_init_dev(void)
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write16(0xbf, &uart->lcr);
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/* 7. Set dll and dlh to the desired values (table 19-25) */
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if (CONFIG_CONSOLE_SERIAL_9600) {
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write16(0x01, &uart->dlh);
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write16(0x38, &uart->dll);
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} else if (CONFIG_CONSOLE_SERIAL_19200) {
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write16(0x00, &uart->dlh);
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write16(0x9c, &uart->dll);
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} else if (CONFIG_CONSOLE_SERIAL_38400) {
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write16(0x00, &uart->dlh);
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write16(0x4e, &uart->dll);
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} else if (CONFIG_CONSOLE_SERIAL_57600) {
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write16(0x00, &uart->dlh);
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write16(0x34, &uart->dll);
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} else if (CONFIG_CONSOLE_SERIAL_115200) {
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write16(0x00, &uart->dlh);
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write16(0x1a, &uart->dll);
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} else {
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/* Unrecognized baud rate? */
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}
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write16((div >> 8), &uart->dlh);
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write16((div & 0xff), &uart->dll);
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/* 8. Switch to operational mode to access ier */
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write16(0x0, &uart->lcr);
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@ -173,12 +157,24 @@ static void am335x_uart_tx_byte(unsigned char data)
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return write8(data, &uart->thr);
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}
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unsigned int uart_platform_refclk(void)
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{
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return 48000000;
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}
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static void am335x_uart_init_dev(void)
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{
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uint16_t div = (uint16_t) uart_baudrate_divisor(
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default_baudrate(), uart_platform_refclk(), 16);
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am335x_uart_init(div);
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}
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#if !defined(__PRE_RAM__)
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uint32_t uartmem_getbaseaddr(void)
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{
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return CONFIG_CONSOLE_SERIAL_UART_ADDRESS;
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}
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#if !defined(__PRE_RAM__)
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static const struct console_driver exynos5_uart_console __console = {
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.init = am335x_uart_init_dev,
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.tx_byte = am335x_uart_tx_byte,
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