u-boot/drivers/serial/serial_zynq.c

236 lines
5.7 KiB
C
Raw Normal View History

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
* Copyright (C) 2011-2012 Xilinx, Inc. All rights reserved.
*/
#include <clk.h>
#include <common.h>
#include <debug_uart.h>
#include <dm.h>
#include <errno.h>
#include <fdtdec.h>
#include <watchdog.h>
#include <asm/io.h>
#include <linux/compiler.h>
#include <serial.h>
DECLARE_GLOBAL_DATA_PTR;
#define ZYNQ_UART_SR_TXACTIVE BIT(11) /* TX active */
#define ZYNQ_UART_SR_TXFULL BIT(4) /* TX FIFO full */
#define ZYNQ_UART_SR_RXEMPTY BIT(1) /* RX FIFO empty */
#define ZYNQ_UART_CR_TX_EN BIT(4) /* TX enabled */
#define ZYNQ_UART_CR_RX_EN BIT(2) /* RX enabled */
#define ZYNQ_UART_CR_TXRST BIT(1) /* TX logic reset */
#define ZYNQ_UART_CR_RXRST BIT(0) /* RX logic reset */
#define ZYNQ_UART_MR_PARITY_NONE 0x00000020 /* No parity mode */
struct uart_zynq {
u32 control; /* 0x0 - Control Register [8:0] */
u32 mode; /* 0x4 - Mode Register [10:0] */
u32 reserved1[4];
u32 baud_rate_gen; /* 0x18 - Baud Rate Generator [15:0] */
u32 reserved2[4];
u32 channel_sts; /* 0x2c - Channel Status [11:0] */
u32 tx_rx_fifo; /* 0x30 - FIFO [15:0] or [7:0] */
u32 baud_rate_divider; /* 0x34 - Baud Rate Divider [7:0] */
};
struct zynq_uart_platdata {
struct uart_zynq *regs;
};
/* Set up the baud rate in gd struct */
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;
/* Covering case where input clock is so slow */
if (clock < 1000000 && baud > 4800)
baud = 4800;
/* master clock
* Baud rate = ------------------
* bgen * (bdiv + 1)
*
* Find acceptable values for baud generation.
*/
for (bdiv = 4; bdiv < 255; bdiv++) {
bgen = clock / (baud * (bdiv + 1));
if (bgen < 2 || bgen > 65535)
continue;
calc_baud = clock / (bgen * (bdiv + 1));
/*
* Use first calculated baudrate with
* an acceptable (<3%) error
*/
if (baud > calc_baud)
calc_bauderror = baud - calc_baud;
else
calc_bauderror = calc_baud - baud;
if (((calc_bauderror * 100) / baud) < 3)
break;
}
writel(bdiv, &regs->baud_rate_divider);
writel(bgen, &regs->baud_rate_gen);
}
/* 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 */
}
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 int zynq_serial_setbrg(struct udevice *dev, int baudrate)
{
struct zynq_uart_platdata *platdata = dev_get_platdata(dev);
unsigned long clock;
int ret;
struct clk clk;
ret = clk_get_by_index(dev, 0, &clk);
if (ret < 0) {
dev_err(dev, "failed to get clock\n");
return ret;
}
clock = clk_get_rate(&clk);
if (IS_ERR_VALUE(clock)) {
dev_err(dev, "failed to get rate\n");
return clock;
}
debug("%s: CLK %ld\n", __func__, clock);
ret = clk_enable(&clk);
if (ret && ret != -ENOSYS) {
dev_err(dev, "failed to enable clock\n");
return ret;
}
_uart_zynq_serial_setbrg(platdata->regs, clock, baudrate);
return 0;
}
static int zynq_serial_probe(struct udevice *dev)
{
struct zynq_uart_platdata *platdata = dev_get_platdata(dev);
/* No need to reinitialize the UART after relocation */
if (gd->flags & GD_FLG_RELOC)
return 0;
_uart_zynq_serial_init(platdata->regs);
return 0;
}
static int zynq_serial_getc(struct udevice *dev)
{
struct zynq_uart_platdata *platdata = dev_get_platdata(dev);
struct uart_zynq *regs = platdata->regs;
if (readl(&regs->channel_sts) & ZYNQ_UART_SR_RXEMPTY)
return -EAGAIN;
return readl(&regs->tx_rx_fifo);
}
static int zynq_serial_putc(struct udevice *dev, const char ch)
{
struct zynq_uart_platdata *platdata = dev_get_platdata(dev);
return _uart_zynq_serial_putc(platdata->regs, ch);
}
static int zynq_serial_pending(struct udevice *dev, bool input)
{
struct zynq_uart_platdata *platdata = dev_get_platdata(dev);
struct uart_zynq *regs = platdata->regs;
if (input)
return !(readl(&regs->channel_sts) & ZYNQ_UART_SR_RXEMPTY);
else
return !!(readl(&regs->channel_sts) & ZYNQ_UART_SR_TXACTIVE);
}
static int zynq_serial_ofdata_to_platdata(struct udevice *dev)
{
struct zynq_uart_platdata *platdata = dev_get_platdata(dev);
platdata->regs = (struct uart_zynq *)dev_read_addr(dev);
if (IS_ERR(platdata->regs))
return PTR_ERR(platdata->regs);
return 0;
}
static const struct dm_serial_ops zynq_serial_ops = {
.putc = zynq_serial_putc,
.pending = zynq_serial_pending,
.getc = zynq_serial_getc,
.setbrg = zynq_serial_setbrg,
};
static const struct udevice_id zynq_serial_ids[] = {
{ .compatible = "xlnx,xuartps" },
{ .compatible = "cdns,uart-r1p8" },
{ .compatible = "cdns,uart-r1p12" },
{ }
};
U_BOOT_DRIVER(serial_zynq) = {
.name = "serial_zynq",
.id = UCLASS_SERIAL,
.of_match = zynq_serial_ids,
.ofdata_to_platdata = zynq_serial_ofdata_to_platdata,
.platdata_auto_alloc_size = sizeof(struct zynq_uart_platdata),
.probe = zynq_serial_probe,
.ops = &zynq_serial_ops,
};
#ifdef CONFIG_DEBUG_UART_ZYNQ
static inline 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