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/*
* Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <common.h>
#include <dm.h>
#include <serial.h>
DECLARE_GLOBAL_DATA_PTR;
struct arc_serial_regs {
unsigned int id0;
unsigned int id1;
unsigned int id2;
unsigned int id3;
unsigned int data;
unsigned int status;
unsigned int baudl;
unsigned int baudh;
};
struct arc_serial_platdata {
struct arc_serial_regs *reg;
unsigned int uartclk;
};
/* Bit definitions of STATUS register */
#define UART_RXEMPTY (1 << 5)
#define UART_OVERFLOW_ERR (1 << 1)
#define UART_TXEMPTY (1 << 7)
static int arc_serial_setbrg(struct udevice *dev, int baudrate)
{
struct arc_serial_platdata *plat = dev->platdata;
struct arc_serial_regs *const regs = plat->reg;
int arc_console_baud = gd->cpu_clk / (baudrate * 4) - 1;
writeb(arc_console_baud & 0xff, ®s->baudl);
#ifdef CONFIG_ARC
/*
* UART ISS(Instruction Set simulator) emulation has a subtle bug:
* A existing value of Baudh = 0 is used as a indication to startup
* it's internal state machine.
* Thus if baudh is set to 0, 2 times, it chokes.
* This happens with BAUD=115200 and the formaula above
* Until that is fixed, when running on ISS, we will set baudh to !0
*/
if (gd->arch.running_on_hw)
writeb((arc_console_baud & 0xff00) >> 8, ®s->baudh);
else
writeb(1, ®s->baudh);
#else
writeb((arc_console_baud & 0xff00) >> 8, ®s->baudh);
#endif
return 0;
}
static int arc_serial_putc(struct udevice *dev, const char c)
{
struct arc_serial_platdata *plat = dev->platdata;
struct arc_serial_regs *const regs = plat->reg;
while (!(readb(®s->status) & UART_TXEMPTY))
;
writeb(c, ®s->data);
return 0;
}
static int arc_serial_tstc(struct arc_serial_regs *const regs)
{
return !(readb(®s->status) & UART_RXEMPTY);
}
static int arc_serial_pending(struct udevice *dev, bool input)
{
struct arc_serial_platdata *plat = dev->platdata;
struct arc_serial_regs *const regs = plat->reg;
uint32_t status = readb(®s->status);
if (input)
return status & UART_RXEMPTY ? 0 : 1;
else
return status & UART_TXEMPTY ? 0 : 1;
}
static int arc_serial_getc(struct udevice *dev)
{
struct arc_serial_platdata *plat = dev->platdata;
struct arc_serial_regs *const regs = plat->reg;
while (!arc_serial_tstc(regs))
;
/* Check for overflow errors */
if (readb(®s->status) & UART_OVERFLOW_ERR)
return 0;
return readb(®s->data) & 0xFF;
}
static int arc_serial_probe(struct udevice *dev)
{
return 0;
}
static const struct dm_serial_ops arc_serial_ops = {
.putc = arc_serial_putc,
.pending = arc_serial_pending,
.getc = arc_serial_getc,
.setbrg = arc_serial_setbrg,
};
static const struct udevice_id arc_serial_ids[] = {
{ .compatible = "snps,arc-uart" },
{ }
};
static int arc_serial_ofdata_to_platdata(struct udevice *dev)
{
struct arc_serial_platdata *plat = dev_get_platdata(dev);
DECLARE_GLOBAL_DATA_PTR;
plat->reg = (struct arc_serial_regs *)dev_get_addr(dev);
plat->uartclk = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
"clock-frequency", 0);
return 0;
}
U_BOOT_DRIVER(serial_arc) = {
.name = "serial_arc",
.id = UCLASS_SERIAL,
.of_match = arc_serial_ids,
.ofdata_to_platdata = arc_serial_ofdata_to_platdata,
.probe = arc_serial_probe,
.ops = &arc_serial_ops,
.flags = DM_FLAG_PRE_RELOC,
};
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