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arm: zynq: Support the debug UART 

Add support for the debug UART to assist with early debugging. Enable it
for Zybo as an example.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
utp
Simon Glass 2015-10-17 19:41:22 -06:00 committed by Michal Simek
parent bd44758a41
commit c54c0a4c1c
4 changed files with 78 additions and 16 deletions
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6
arch/arm/mach-zynq/spl.c
View File

@ -4,6 +4,7 @@
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <debug_uart.h>
#include <spl.h>
#include <asm/io.h>
@ -18,6 +19,11 @@ void board_init_f(ulong dummy)
ps7_init();
arch_cpu_init();
/*
* The debug UART can be used from this point:
* debug_uart_init();
* printch('x');
*/
}
#ifdef CONFIG_SPL_BOARD_INIT

4
configs/zynq_zybo_defconfig
View File

@ -11,3 +11,7 @@ CONFIG_FIT_SIGNATURE=y
# CONFIG_CMD_SETEXPR is not set
CONFIG_OF_SEPARATE=y
CONFIG_NET_RANDOM_ETHADDR=y
CONFIG_DEBUG_UART=y
CONFIG_DEBUG_UART_ZYNQ=y
CONFIG_DEBUG_UART_BASE=0xe0001000
CONFIG_DEBUG_UART_CLOCK=50000000

7
drivers/serial/Kconfig
View File

@ -91,6 +91,13 @@ config DEBUG_UART_S5P
will need to provide parameters to make this work. The driver will
be available until the real driver-model serial is running.
config DEBUG_UART_ZYNQ
bool "Xilinx Zynq"
help
Select this to enable a debug UART using the serial_s5p driver. You
will need to provide parameters to make this work. The driver will
be available until the real driver-model serial is running.
endchoice
config DEBUG_UART_BASE

77
drivers/serial/serial_zynq.c
View File

@ -6,6 +6,7 @@
*/
#include <common.h>
#include <errno.h>
#include <fdtdec.h>
#include <watchdog.h>
#include <asm/io.h>
@ -43,20 +44,16 @@ static struct uart_zynq *uart_zynq_ports[2] = {
};
/* Set up the baud rate in gd struct */
static void uart_zynq_serial_setbrg(const int port)
static void _uart_zynq_serial_setbrg(struct uart_zynq *regs,
unsigned long clock, unsigned long baud)
{
/* Calculation results. */
unsigned int calc_bauderror, bdiv, bgen;
unsigned long calc_baud = 0;
unsigned long baud;
unsigned long clock = get_uart_clk(port);
struct uart_zynq *regs = uart_zynq_ports[port];
/* Covering case where input clock is so slow */
if (clock < 1000000 && gd->baudrate > 4800)
gd->baudrate = 4800;
baud = gd->baudrate;
if (clock < 1000000 && baud > 4800)
baud = 4800;
/* master clock
* Baud rate = ------------------
@ -87,6 +84,24 @@ static void uart_zynq_serial_setbrg(const int port)
writel(bgen, &regs->baud_rate_gen);
}
/* Set up the baud rate in gd struct */
static void uart_zynq_serial_setbrg(const int port)
{
unsigned long clock = get_uart_clk(port);
struct uart_zynq *regs = uart_zynq_ports[port];
return _uart_zynq_serial_setbrg(regs, clock, gd->baudrate);
}
/* Initialize the UART, with...some settings. */
static void _uart_zynq_serial_init(struct uart_zynq *regs)
{
/* RX/TX enabled & reset */
writel(ZYNQ_UART_CR_TX_EN | ZYNQ_UART_CR_RX_EN | ZYNQ_UART_CR_TXRST | \
ZYNQ_UART_CR_RXRST, &regs->control);
writel(ZYNQ_UART_MR_PARITY_NONE, &regs->mode); /* 8 bit, no parity */
}
/* Initialize the UART, with...some settings. */
static int uart_zynq_serial_init(const int port)
{
@ -95,28 +110,33 @@ static int uart_zynq_serial_init(const int port)
if (!regs)
return -1;
/* RX/TX enabled & reset */
writel(ZYNQ_UART_CR_TX_EN | ZYNQ_UART_CR_RX_EN | ZYNQ_UART_CR_TXRST | \
ZYNQ_UART_CR_RXRST, &regs->control);
writel(ZYNQ_UART_MR_PARITY_NONE, &regs->mode); /* 8 bit, no parity */
_uart_zynq_serial_init(regs);
uart_zynq_serial_setbrg(port);
return 0;
}
static int _uart_zynq_serial_putc(struct uart_zynq *regs, const char c)
{
if (readl(&regs->channel_sts) & ZYNQ_UART_SR_TXFULL)
return -EAGAIN;
writel(c, &regs->tx_rx_fifo);
return 0;
}
static void uart_zynq_serial_putc(const char c, const int port)
{
struct uart_zynq *regs = uart_zynq_ports[port];
while ((readl(&regs->channel_sts) & ZYNQ_UART_SR_TXFULL) != 0)
while (_uart_zynq_serial_putc(regs, c) == -EAGAIN)
WATCHDOG_RESET();
if (c == '\n') {
writel('\r', &regs->tx_rx_fifo);
while ((readl(&regs->channel_sts) & ZYNQ_UART_SR_TXFULL) != 0)
while (_uart_zynq_serial_putc(regs, '\r') == -EAGAIN)
WATCHDOG_RESET();
}
writel(c, &regs->tx_rx_fifo);
}
static void uart_zynq_serial_puts(const char *s, const int port)
@ -218,3 +238,28 @@ void zynq_serial_initialize(void)
serial_register(&uart_zynq_serial0_device);
serial_register(&uart_zynq_serial1_device);
}
#ifdef CONFIG_DEBUG_UART_ZYNQ
#include <debug_uart.h>
void _debug_uart_init(void)
{
struct uart_zynq *regs = (struct uart_zynq *)CONFIG_DEBUG_UART_BASE;
_uart_zynq_serial_init(regs);
_uart_zynq_serial_setbrg(regs, CONFIG_DEBUG_UART_CLOCK,
CONFIG_BAUDRATE);
}
static inline void _debug_uart_putc(int ch)
{
struct uart_zynq *regs = (struct uart_zynq *)CONFIG_DEBUG_UART_BASE;
while (_uart_zynq_serial_putc(regs, ch) == -EAGAIN)
WATCHDOG_RESET();
}
DEBUG_UART_FUNCS
#endif