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![Sagar Shrikant Kadam](/assets/img/avatar_default.png)
In y-modem transfer mode, tstc/getc fail to check if there is any data available / received in RX FIFO, and so y-modem transfer never succeeds. Using receive watermark bit within ip register fixes the issue. This patch is based on commit c7392b7bc4e1 ("Use the RX watermark interrupt pending bit for TSTC") available at[1] [1] https://github.com/sifive/HiFive_U-Boot/tree/regression Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com> Reviewed-by: Anup Patel <anup.patel@wdc.com> Tested-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Padmarao Begari <padmarao.begari@microchip.com> Tested-by: Padmarao Begari <padmarao.begari@microchip.com>
231 lines
5.2 KiB
C
231 lines
5.2 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2018 Anup Patel <anup@brainfault.org>
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*/
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#include <common.h>
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#include <clk.h>
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#include <debug_uart.h>
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#include <dm.h>
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#include <errno.h>
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#include <fdtdec.h>
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#include <watchdog.h>
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#include <asm/io.h>
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#include <linux/compiler.h>
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#include <serial.h>
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DECLARE_GLOBAL_DATA_PTR;
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#define UART_TXFIFO_FULL 0x80000000
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#define UART_RXFIFO_EMPTY 0x80000000
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#define UART_RXFIFO_DATA 0x000000ff
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#define UART_TXCTRL_TXEN 0x1
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#define UART_RXCTRL_RXEN 0x1
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/* IP register */
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#define UART_IP_RXWM 0x2
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struct uart_sifive {
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u32 txfifo;
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u32 rxfifo;
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u32 txctrl;
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u32 rxctrl;
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u32 ie;
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u32 ip;
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u32 div;
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};
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struct sifive_uart_platdata {
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unsigned long clock;
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struct uart_sifive *regs;
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};
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/**
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* Find minimum divisor divides in_freq to max_target_hz;
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* Based on uart driver n SiFive FSBL.
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*
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* f_baud = f_in / (div + 1) => div = (f_in / f_baud) - 1
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* The nearest integer solution requires rounding up as to not exceed
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* max_target_hz.
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* div = ceil(f_in / f_baud) - 1
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* = floor((f_in - 1 + f_baud) / f_baud) - 1
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* This should not overflow as long as (f_in - 1 + f_baud) does not exceed
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* 2^32 - 1, which is unlikely since we represent frequencies in kHz.
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*/
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static inline unsigned int uart_min_clk_divisor(unsigned long in_freq,
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unsigned long max_target_hz)
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{
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unsigned long quotient =
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(in_freq + max_target_hz - 1) / (max_target_hz);
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/* Avoid underflow */
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if (quotient == 0)
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return 0;
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else
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return quotient - 1;
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}
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/* Set up the baud rate in gd struct */
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static void _sifive_serial_setbrg(struct uart_sifive *regs,
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unsigned long clock, unsigned long baud)
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{
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writel((uart_min_clk_divisor(clock, baud)), ®s->div);
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}
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static void _sifive_serial_init(struct uart_sifive *regs)
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{
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writel(UART_TXCTRL_TXEN, ®s->txctrl);
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writel(UART_RXCTRL_RXEN, ®s->rxctrl);
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writel(0, ®s->ie);
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}
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static int _sifive_serial_putc(struct uart_sifive *regs, const char c)
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{
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if (readl(®s->txfifo) & UART_TXFIFO_FULL)
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return -EAGAIN;
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writel(c, ®s->txfifo);
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return 0;
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}
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static int _sifive_serial_getc(struct uart_sifive *regs)
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{
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int ch = readl(®s->rxfifo);
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if (ch & UART_RXFIFO_EMPTY)
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return -EAGAIN;
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ch &= UART_RXFIFO_DATA;
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return ch;
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}
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static int sifive_serial_setbrg(struct udevice *dev, int baudrate)
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{
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int ret;
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struct clk clk;
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struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
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u32 clock = 0;
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ret = clk_get_by_index(dev, 0, &clk);
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if (IS_ERR_VALUE(ret)) {
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debug("SiFive UART failed to get clock\n");
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ret = dev_read_u32(dev, "clock-frequency", &clock);
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if (IS_ERR_VALUE(ret)) {
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debug("SiFive UART clock not defined\n");
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return 0;
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}
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} else {
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clock = clk_get_rate(&clk);
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if (IS_ERR_VALUE(clock)) {
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debug("SiFive UART clock get rate failed\n");
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return 0;
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}
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}
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platdata->clock = clock;
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_sifive_serial_setbrg(platdata->regs, platdata->clock, baudrate);
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return 0;
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}
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static int sifive_serial_probe(struct udevice *dev)
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{
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struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
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/* No need to reinitialize the UART after relocation */
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if (gd->flags & GD_FLG_RELOC)
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return 0;
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_sifive_serial_init(platdata->regs);
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return 0;
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}
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static int sifive_serial_getc(struct udevice *dev)
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{
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int c;
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struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
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struct uart_sifive *regs = platdata->regs;
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while ((c = _sifive_serial_getc(regs)) == -EAGAIN) ;
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return c;
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}
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static int sifive_serial_putc(struct udevice *dev, const char ch)
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{
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int rc;
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struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
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while ((rc = _sifive_serial_putc(platdata->regs, ch)) == -EAGAIN) ;
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return rc;
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}
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static int sifive_serial_pending(struct udevice *dev, bool input)
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{
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struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
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struct uart_sifive *regs = platdata->regs;
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if (input)
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return (readl(®s->ip) & UART_IP_RXWM);
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else
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return !!(readl(®s->txfifo) & UART_TXFIFO_FULL);
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}
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static int sifive_serial_ofdata_to_platdata(struct udevice *dev)
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{
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struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
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platdata->regs = (struct uart_sifive *)dev_read_addr(dev);
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if (IS_ERR(platdata->regs))
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return PTR_ERR(platdata->regs);
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return 0;
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}
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static const struct dm_serial_ops sifive_serial_ops = {
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.putc = sifive_serial_putc,
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.getc = sifive_serial_getc,
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.pending = sifive_serial_pending,
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.setbrg = sifive_serial_setbrg,
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};
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static const struct udevice_id sifive_serial_ids[] = {
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{ .compatible = "sifive,uart0" },
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{ }
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};
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U_BOOT_DRIVER(serial_sifive) = {
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.name = "serial_sifive",
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.id = UCLASS_SERIAL,
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.of_match = sifive_serial_ids,
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.ofdata_to_platdata = sifive_serial_ofdata_to_platdata,
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.platdata_auto_alloc_size = sizeof(struct sifive_uart_platdata),
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.probe = sifive_serial_probe,
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.ops = &sifive_serial_ops,
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};
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#ifdef CONFIG_DEBUG_UART_SIFIVE
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static inline void _debug_uart_init(void)
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{
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struct uart_sifive *regs =
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(struct uart_sifive *)CONFIG_DEBUG_UART_BASE;
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_sifive_serial_setbrg(regs, CONFIG_DEBUG_UART_CLOCK,
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CONFIG_BAUDRATE);
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_sifive_serial_init(regs);
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}
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static inline void _debug_uart_putc(int ch)
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{
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struct uart_sifive *regs =
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(struct uart_sifive *)CONFIG_DEBUG_UART_BASE;
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while (_sifive_serial_putc(regs, ch) == -EAGAIN)
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WATCHDOG_RESET();
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}
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DEBUG_UART_FUNCS
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#endif
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