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u-boot/drivers/serial/serial_sh.c
Marek Vasut f5ba5c90d4 serial: sh: Improve FIFO empty check on RX 
If the SCIF is receiving data quickly enough, it may happen that the
SCxSR_RDxF flag is cleared in sh_serial_getc_generic(), while the
FIFO still contains data. If that happens, the serial_getc_check()
reports no data in the FIFO as the flag is no longer set. Add one
more check, if the SCxSR_RDxF is not set, read out the FIFO level
and if there are still characters in the FIFO, permit reading them
out.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
2020-09-01 14:46:41 +02:00

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// SPDX-License-Identifier: GPL-2.0+
/*
* SuperH SCIF device driver.
* Copyright (C) 2013 Renesas Electronics Corporation
* Copyright (C) 2007,2008,2010, 2014 Nobuhiro Iwamatsu
* Copyright (C) 2002 - 2008 Paul Mundt
*/
#include <common.h>
#include <errno.h>
#include <clk.h>
#include <dm.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <serial.h>
#include <linux/compiler.h>
#include <dm/platform_data/serial_sh.h>
#include <linux/delay.h>
#include "serial_sh.h"
DECLARE_GLOBAL_DATA_PTR;
#if defined(CONFIG_CPU_SH7780)
static int scif_rxfill(struct uart_port *port)
{
return sci_in(port, SCRFDR) & 0xff;
}
#elif defined(CONFIG_CPU_SH7763)
static int scif_rxfill(struct uart_port *port)
{
if ((port->mapbase == 0xffe00000) ||
(port->mapbase == 0xffe08000)) {
/* SCIF0/1*/
return sci_in(port, SCRFDR) & 0xff;
} else {
/* SCIF2 */
return sci_in(port, SCFDR) & SCIF2_RFDC_MASK;
}
}
#else
static int scif_rxfill(struct uart_port *port)
{
return sci_in(port, SCFDR) & SCIF_RFDC_MASK;
}
#endif
static void sh_serial_init_generic(struct uart_port *port)
{
sci_out(port, SCSCR , SCSCR_INIT(port));
sci_out(port, SCSCR , SCSCR_INIT(port));
sci_out(port, SCSMR, 0);
sci_out(port, SCSMR, 0);
sci_out(port, SCFCR, SCFCR_RFRST|SCFCR_TFRST);
sci_in(port, SCFCR);
sci_out(port, SCFCR, 0);
#if defined(CONFIG_RZA1)
sci_out(port, SCSPTR, 0x0003);
#endif
}
static void
sh_serial_setbrg_generic(struct uart_port *port, int clk, int baudrate)
{
if (port->clk_mode == EXT_CLK) {
unsigned short dl = DL_VALUE(baudrate, clk);
sci_out(port, DL, dl);
/* Need wait: Clock * 1/dl * 1/16 */
udelay((1000000 * dl * 16 / clk) * 1000 + 1);
} else {
sci_out(port, SCBRR, SCBRR_VALUE(baudrate, clk));
}
}
static void handle_error(struct uart_port *port)
{
sci_in(port, SCxSR);
sci_out(port, SCxSR, SCxSR_ERROR_CLEAR(port));
sci_in(port, SCLSR);
sci_out(port, SCLSR, 0x00);
}
static int serial_raw_putc(struct uart_port *port, const char c)
{
/* Tx fifo is empty */
if (!(sci_in(port, SCxSR) & SCxSR_TEND(port)))
return -EAGAIN;
sci_out(port, SCxTDR, c);
sci_out(port, SCxSR, sci_in(port, SCxSR) & ~SCxSR_TEND(port));
return 0;
}
static int serial_rx_fifo_level(struct uart_port *port)
{
return scif_rxfill(port);
}
static int sh_serial_tstc_generic(struct uart_port *port)
{
if (sci_in(port, SCxSR) & SCIF_ERRORS) {
handle_error(port);
return 0;
}
return serial_rx_fifo_level(port) ? 1 : 0;
}
static int serial_getc_check(struct uart_port *port)
{
unsigned short status;
status = sci_in(port, SCxSR);
if (status & SCIF_ERRORS)
handle_error(port);
if (sci_in(port, SCLSR) & SCxSR_ORER(port))
handle_error(port);
status &= (SCIF_DR | SCxSR_RDxF(port));
if (status)
return status;
return scif_rxfill(port);
}
static int sh_serial_getc_generic(struct uart_port *port)
{
unsigned short status;
char ch;
if (!serial_getc_check(port))
return -EAGAIN;
ch = sci_in(port, SCxRDR);
status = sci_in(port, SCxSR);
sci_out(port, SCxSR, SCxSR_RDxF_CLEAR(port));
if (status & SCIF_ERRORS)
handle_error(port);
if (sci_in(port, SCLSR) & SCxSR_ORER(port))
handle_error(port);
return ch;
}
#if CONFIG_IS_ENABLED(DM_SERIAL)
static int sh_serial_pending(struct udevice *dev, bool input)
{
struct uart_port *priv = dev_get_priv(dev);
return sh_serial_tstc_generic(priv);
}
static int sh_serial_putc(struct udevice *dev, const char ch)
{
struct uart_port *priv = dev_get_priv(dev);
return serial_raw_putc(priv, ch);
}
static int sh_serial_getc(struct udevice *dev)
{
struct uart_port *priv = dev_get_priv(dev);
return sh_serial_getc_generic(priv);
}
static int sh_serial_setbrg(struct udevice *dev, int baudrate)
{
struct sh_serial_platdata *plat = dev_get_platdata(dev);
struct uart_port *priv = dev_get_priv(dev);
sh_serial_setbrg_generic(priv, plat->clk, baudrate);
return 0;
}
static int sh_serial_probe(struct udevice *dev)
{
struct sh_serial_platdata *plat = dev_get_platdata(dev);
struct uart_port *priv = dev_get_priv(dev);
priv->membase = (unsigned char *)plat->base;
priv->mapbase = plat->base;
priv->type = plat->type;
priv->clk_mode = plat->clk_mode;
sh_serial_init_generic(priv);
return 0;
}
static const struct dm_serial_ops sh_serial_ops = {
.putc = sh_serial_putc,
.pending = sh_serial_pending,
.getc = sh_serial_getc,
.setbrg = sh_serial_setbrg,
};
#if CONFIG_IS_ENABLED(OF_CONTROL)
static const struct udevice_id sh_serial_id[] ={
{.compatible = "renesas,sci", .data = PORT_SCI},
{.compatible = "renesas,scif", .data = PORT_SCIF},
{.compatible = "renesas,scifa", .data = PORT_SCIFA},
{}
};
static int sh_serial_ofdata_to_platdata(struct udevice *dev)
{
struct sh_serial_platdata *plat = dev_get_platdata(dev);
struct clk sh_serial_clk;
fdt_addr_t addr;
int ret;
addr = dev_read_addr(dev);
if (!addr)
return -EINVAL;
plat->base = addr;
ret = clk_get_by_name(dev, "fck", &sh_serial_clk);
if (!ret) {
ret = clk_enable(&sh_serial_clk);
if (!ret)
plat->clk = clk_get_rate(&sh_serial_clk);
} else {
plat->clk = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev),
"clock", 1);
}
plat->type = dev_get_driver_data(dev);
return 0;
}
#endif
U_BOOT_DRIVER(serial_sh) = {
.name = "serial_sh",
.id = UCLASS_SERIAL,
.of_match = of_match_ptr(sh_serial_id),
.ofdata_to_platdata = of_match_ptr(sh_serial_ofdata_to_platdata),
.platdata_auto_alloc_size = sizeof(struct sh_serial_platdata),
.probe = sh_serial_probe,
.ops = &sh_serial_ops,
#if !CONFIG_IS_ENABLED(OF_CONTROL)
.flags = DM_FLAG_PRE_RELOC,
#endif
.priv_auto_alloc_size = sizeof(struct uart_port),
};
#else /* CONFIG_DM_SERIAL */
#if defined(CONFIG_CONS_SCIF0)
# define SCIF_BASE SCIF0_BASE
#elif defined(CONFIG_CONS_SCIF1)
# define SCIF_BASE SCIF1_BASE
#elif defined(CONFIG_CONS_SCIF2)
# define SCIF_BASE SCIF2_BASE
#elif defined(CONFIG_CONS_SCIF3)
# define SCIF_BASE SCIF3_BASE
#elif defined(CONFIG_CONS_SCIF4)
# define SCIF_BASE SCIF4_BASE
#elif defined(CONFIG_CONS_SCIF5)
# define SCIF_BASE SCIF5_BASE
#elif defined(CONFIG_CONS_SCIF6)
# define SCIF_BASE SCIF6_BASE
#elif defined(CONFIG_CONS_SCIF7)
# define SCIF_BASE SCIF7_BASE
#elif defined(CONFIG_CONS_SCIFA0)
# define SCIF_BASE SCIFA0_BASE
#else
# error "Default SCIF doesn't set....."
#endif
#if defined(CONFIG_SCIF_A)
#define SCIF_BASE_PORT PORT_SCIFA
#elif defined(CONFIG_SCI)
#define SCIF_BASE_PORT PORT_SCI
#else
#define SCIF_BASE_PORT PORT_SCIF
#endif
static struct uart_port sh_sci = {
.membase = (unsigned char *)SCIF_BASE,
.mapbase = SCIF_BASE,
.type = SCIF_BASE_PORT,
#ifdef CONFIG_SCIF_USE_EXT_CLK
.clk_mode = EXT_CLK,
#endif
};
static void sh_serial_setbrg(void)
{
DECLARE_GLOBAL_DATA_PTR;
struct uart_port *port = &sh_sci;
sh_serial_setbrg_generic(port, CONFIG_SH_SCIF_CLK_FREQ, gd->baudrate);
}
static int sh_serial_init(void)
{
struct uart_port *port = &sh_sci;
sh_serial_init_generic(port);
serial_setbrg();
return 0;
}
static void sh_serial_putc(const char c)
{
struct uart_port *port = &sh_sci;
if (c == '\n') {
while (1) {
if (serial_raw_putc(port, '\r') != -EAGAIN)
break;
}
}
while (1) {
if (serial_raw_putc(port, c) != -EAGAIN)
break;
}
}
static int sh_serial_tstc(void)
{
struct uart_port *port = &sh_sci;
return sh_serial_tstc_generic(port);
}
static int sh_serial_getc(void)
{
struct uart_port *port = &sh_sci;
int ch;
while (1) {
ch = sh_serial_getc_generic(port);
if (ch != -EAGAIN)
break;
}
return ch;
}
static struct serial_device sh_serial_drv = {
.name = "sh_serial",
.start = sh_serial_init,
.stop = NULL,
.setbrg = sh_serial_setbrg,
.putc = sh_serial_putc,
.puts = default_serial_puts,
.getc = sh_serial_getc,
.tstc = sh_serial_tstc,
};
void sh_serial_initialize(void)
{
serial_register(&sh_serial_drv);
}
__weak struct serial_device *default_serial_console(void)
{
return &sh_serial_drv;
}
#endif /* CONFIG_DM_SERIAL */
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