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![Michal Simek](/assets/img/avatar_default.png)
The commit a673025535
("serial: zynq: Initialize uart only before
relocation") introduced code which detects relocation which is working for
single uart instance. With multiple instances in place there is a need to
enable and setup every instance. That's why detect if TX is enabled. If it
is then don't initialize uart again.
In post probe setbrg is called to setup baudrate but values should be the
same.
As a side effect of this change is that DECLARE_GLOBAL_DATA_PTR can be
removed completely.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
239 lines
5.8 KiB
C
239 lines
5.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
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* Copyright (C) 2011-2012 Xilinx, Inc. All rights reserved.
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*/
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#include <clk.h>
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#include <common.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 <dm/device_compat.h>
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#include <linux/compiler.h>
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#include <serial.h>
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#include <linux/err.h>
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#define ZYNQ_UART_SR_TXACTIVE BIT(11) /* TX active */
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#define ZYNQ_UART_SR_TXFULL BIT(4) /* TX FIFO full */
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#define ZYNQ_UART_SR_RXEMPTY BIT(1) /* RX FIFO empty */
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#define ZYNQ_UART_CR_TX_EN BIT(4) /* TX enabled */
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#define ZYNQ_UART_CR_RX_EN BIT(2) /* RX enabled */
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#define ZYNQ_UART_CR_TXRST BIT(1) /* TX logic reset */
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#define ZYNQ_UART_CR_RXRST BIT(0) /* RX logic reset */
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#define ZYNQ_UART_MR_PARITY_NONE 0x00000020 /* No parity mode */
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struct uart_zynq {
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u32 control; /* 0x0 - Control Register [8:0] */
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u32 mode; /* 0x4 - Mode Register [10:0] */
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u32 reserved1[4];
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u32 baud_rate_gen; /* 0x18 - Baud Rate Generator [15:0] */
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u32 reserved2[4];
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u32 channel_sts; /* 0x2c - Channel Status [11:0] */
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u32 tx_rx_fifo; /* 0x30 - FIFO [15:0] or [7:0] */
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u32 baud_rate_divider; /* 0x34 - Baud Rate Divider [7:0] */
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};
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struct zynq_uart_platdata {
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struct uart_zynq *regs;
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};
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/* Set up the baud rate */
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static void _uart_zynq_serial_setbrg(struct uart_zynq *regs,
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unsigned long clock, unsigned long baud)
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{
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/* Calculation results. */
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unsigned int calc_bauderror, bdiv, bgen;
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unsigned long calc_baud = 0;
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/* Covering case where input clock is so slow */
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if (clock < 1000000 && baud > 4800)
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baud = 4800;
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/* master clock
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* Baud rate = ------------------
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* bgen * (bdiv + 1)
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*
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* Find acceptable values for baud generation.
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*/
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for (bdiv = 4; bdiv < 255; bdiv++) {
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bgen = clock / (baud * (bdiv + 1));
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if (bgen < 2 || bgen > 65535)
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continue;
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calc_baud = clock / (bgen * (bdiv + 1));
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/*
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* Use first calculated baudrate with
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* an acceptable (<3%) error
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*/
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if (baud > calc_baud)
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calc_bauderror = baud - calc_baud;
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else
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calc_bauderror = calc_baud - baud;
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if (((calc_bauderror * 100) / baud) < 3)
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break;
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}
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writel(bdiv, ®s->baud_rate_divider);
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writel(bgen, ®s->baud_rate_gen);
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}
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/* Initialize the UART, with...some settings. */
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static void _uart_zynq_serial_init(struct uart_zynq *regs)
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{
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/* RX/TX enabled & reset */
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writel(ZYNQ_UART_CR_TX_EN | ZYNQ_UART_CR_RX_EN | ZYNQ_UART_CR_TXRST | \
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ZYNQ_UART_CR_RXRST, ®s->control);
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writel(ZYNQ_UART_MR_PARITY_NONE, ®s->mode); /* 8 bit, no parity */
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}
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static int _uart_zynq_serial_putc(struct uart_zynq *regs, const char c)
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{
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if (readl(®s->channel_sts) & ZYNQ_UART_SR_TXFULL)
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return -EAGAIN;
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writel(c, ®s->tx_rx_fifo);
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return 0;
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}
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static int zynq_serial_setbrg(struct udevice *dev, int baudrate)
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{
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struct zynq_uart_platdata *platdata = dev_get_platdata(dev);
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unsigned long clock;
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int ret;
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struct clk clk;
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ret = clk_get_by_index(dev, 0, &clk);
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if (ret < 0) {
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dev_err(dev, "failed to get clock\n");
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return ret;
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}
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clock = clk_get_rate(&clk);
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if (IS_ERR_VALUE(clock)) {
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dev_err(dev, "failed to get rate\n");
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return clock;
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}
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debug("%s: CLK %ld\n", __func__, clock);
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ret = clk_enable(&clk);
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if (ret && ret != -ENOSYS) {
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dev_err(dev, "failed to enable clock\n");
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return ret;
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}
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_uart_zynq_serial_setbrg(platdata->regs, clock, baudrate);
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return 0;
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}
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static int zynq_serial_probe(struct udevice *dev)
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{
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struct zynq_uart_platdata *platdata = dev_get_platdata(dev);
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struct uart_zynq *regs = platdata->regs;
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u32 val;
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/* No need to reinitialize the UART if TX already enabled */
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val = readl(®s->control);
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if (val & ZYNQ_UART_CR_TX_EN)
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return 0;
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_uart_zynq_serial_init(platdata->regs);
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return 0;
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}
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static int zynq_serial_getc(struct udevice *dev)
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{
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struct zynq_uart_platdata *platdata = dev_get_platdata(dev);
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struct uart_zynq *regs = platdata->regs;
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if (readl(®s->channel_sts) & ZYNQ_UART_SR_RXEMPTY)
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return -EAGAIN;
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return readl(®s->tx_rx_fifo);
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}
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static int zynq_serial_putc(struct udevice *dev, const char ch)
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{
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struct zynq_uart_platdata *platdata = dev_get_platdata(dev);
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return _uart_zynq_serial_putc(platdata->regs, ch);
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}
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static int zynq_serial_pending(struct udevice *dev, bool input)
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{
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struct zynq_uart_platdata *platdata = dev_get_platdata(dev);
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struct uart_zynq *regs = platdata->regs;
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if (input)
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return !(readl(®s->channel_sts) & ZYNQ_UART_SR_RXEMPTY);
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else
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return !!(readl(®s->channel_sts) & ZYNQ_UART_SR_TXACTIVE);
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}
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static int zynq_serial_ofdata_to_platdata(struct udevice *dev)
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{
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struct zynq_uart_platdata *platdata = dev_get_platdata(dev);
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platdata->regs = (struct uart_zynq *)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 zynq_serial_ops = {
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.putc = zynq_serial_putc,
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.pending = zynq_serial_pending,
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.getc = zynq_serial_getc,
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.setbrg = zynq_serial_setbrg,
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};
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static const struct udevice_id zynq_serial_ids[] = {
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{ .compatible = "xlnx,xuartps" },
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{ .compatible = "cdns,uart-r1p8" },
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{ .compatible = "cdns,uart-r1p12" },
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{ }
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};
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U_BOOT_DRIVER(serial_zynq) = {
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.name = "serial_zynq",
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.id = UCLASS_SERIAL,
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.of_match = zynq_serial_ids,
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.ofdata_to_platdata = zynq_serial_ofdata_to_platdata,
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.platdata_auto_alloc_size = sizeof(struct zynq_uart_platdata),
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.probe = zynq_serial_probe,
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.ops = &zynq_serial_ops,
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};
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#ifdef CONFIG_DEBUG_UART_ZYNQ
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static inline void _debug_uart_init(void)
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{
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struct uart_zynq *regs = (struct uart_zynq *)CONFIG_DEBUG_UART_BASE;
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_uart_zynq_serial_init(regs);
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_uart_zynq_serial_setbrg(regs, CONFIG_DEBUG_UART_CLOCK,
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CONFIG_BAUDRATE);
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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_zynq *regs = (struct uart_zynq *)CONFIG_DEBUG_UART_BASE;
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while (_uart_zynq_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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