mirror of
https://github.com/AsahiLinux/u-boot
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7de0fe1ac3
Some platforms (e.g. IGEPv2 board) has a broken ns16550 UART that does not set the TEMT bit when the transmitter is empty in SPL. This makes U-Boot to hang while waiting for TEMT to be set. Add a new option to avoid this: CONFIG_SYS_NS16550_BROKEN_TEMT 16550 UART set the Transmitter Empty (TEMT) Bit when all output has finished and the transmitter is totally empty. U-Boot waits for this bit to be set to initialize the serial console. On some broken platforms this bit is not set in SPL making U-Boot to hang while waiting for TEMT. Define this option to avoid it. Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
123 lines
3.7 KiB
C
123 lines
3.7 KiB
C
/*
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* COM1 NS16550 support
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* originally from linux source (arch/powerpc/boot/ns16550.c)
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* modified to use CONFIG_SYS_ISA_MEM and new defines
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*/
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#include <config.h>
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#include <ns16550.h>
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#include <watchdog.h>
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#include <linux/types.h>
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#include <asm/io.h>
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#define UART_LCRVAL UART_LCR_8N1 /* 8 data, 1 stop, no parity */
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#define UART_MCRVAL (UART_MCR_DTR | \
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UART_MCR_RTS) /* RTS/DTR */
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#define UART_FCRVAL (UART_FCR_FIFO_EN | \
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UART_FCR_RXSR | \
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UART_FCR_TXSR) /* Clear & enable FIFOs */
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#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
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#define serial_out(x, y) outb(x, (ulong)y)
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#define serial_in(y) inb((ulong)y)
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#elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE > 0)
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#define serial_out(x, y) out_be32(y, x)
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#define serial_in(y) in_be32(y)
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#elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE < 0)
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#define serial_out(x, y) out_le32(y, x)
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#define serial_in(y) in_le32(y)
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#else
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#define serial_out(x, y) writeb(x, y)
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#define serial_in(y) readb(y)
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#endif
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#ifndef CONFIG_SYS_NS16550_IER
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#define CONFIG_SYS_NS16550_IER 0x00
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#endif /* CONFIG_SYS_NS16550_IER */
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void NS16550_init(NS16550_t com_port, int baud_divisor)
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{
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#if (!defined(CONFIG_SYS_NS16550_BROKEN_TEMT))
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while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
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;
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#endif
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serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
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#if (defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)) || \
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defined(CONFIG_AM33XX)
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serial_out(0x7, &com_port->mdr1); /* mode select reset TL16C750*/
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#endif
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serial_out(UART_LCR_BKSE | UART_LCRVAL, (ulong)&com_port->lcr);
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serial_out(0, &com_port->dll);
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serial_out(0, &com_port->dlm);
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serial_out(UART_LCRVAL, &com_port->lcr);
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serial_out(UART_MCRVAL, &com_port->mcr);
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serial_out(UART_FCRVAL, &com_port->fcr);
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serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
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serial_out(baud_divisor & 0xff, &com_port->dll);
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serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
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serial_out(UART_LCRVAL, &com_port->lcr);
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#if (defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)) || \
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defined(CONFIG_AM33XX) || defined(CONFIG_SOC_DA8XX)
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#if defined(CONFIG_APTIX)
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/* /13 mode so Aptix 6MHz can hit 115200 */
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serial_out(3, &com_port->mdr1);
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#else
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/* /16 is proper to hit 115200 with 48MHz */
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serial_out(0, &com_port->mdr1);
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#endif
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#endif /* CONFIG_OMAP */
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}
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#ifndef CONFIG_NS16550_MIN_FUNCTIONS
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void NS16550_reinit(NS16550_t com_port, int baud_divisor)
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{
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serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
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serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
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serial_out(0, &com_port->dll);
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serial_out(0, &com_port->dlm);
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serial_out(UART_LCRVAL, &com_port->lcr);
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serial_out(UART_MCRVAL, &com_port->mcr);
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serial_out(UART_FCRVAL, &com_port->fcr);
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serial_out(UART_LCR_BKSE, &com_port->lcr);
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serial_out(baud_divisor & 0xff, &com_port->dll);
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serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
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serial_out(UART_LCRVAL, &com_port->lcr);
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}
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#endif /* CONFIG_NS16550_MIN_FUNCTIONS */
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void NS16550_putc(NS16550_t com_port, char c)
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{
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while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
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;
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serial_out(c, &com_port->thr);
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/*
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* Call watchdog_reset() upon newline. This is done here in putc
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* since the environment code uses a single puts() to print the complete
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* environment upon "printenv". So we can't put this watchdog call
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* in puts().
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*/
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if (c == '\n')
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WATCHDOG_RESET();
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}
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#ifndef CONFIG_NS16550_MIN_FUNCTIONS
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char NS16550_getc(NS16550_t com_port)
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{
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while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
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#if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_TTY)
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extern void usbtty_poll(void);
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usbtty_poll();
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#endif
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WATCHDOG_RESET();
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}
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return serial_in(&com_port->rbr);
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}
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int NS16550_tstc(NS16550_t com_port)
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{
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return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
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}
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#endif /* CONFIG_NS16550_MIN_FUNCTIONS */
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