Commit b7396a38 authored by Chunyan Zhang's avatar Chunyan Zhang Committed by Greg Kroah-Hartman
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tty/serial: Add Spreadtrum sc9836-uart driver support



Add a full sc9836-uart driver for SC9836 SoC which is based on the
spreadtrum sharkl64 platform.
This driver also support earlycon.
Originally-by: default avatarLanqing Liu <lanqing.liu@spreadtrum.com>
Signed-off-by: default avatarOrson Zhai <orson.zhai@spreadtrum.com>
Signed-off-by: default avatarChunyan Zhang <chunyan.zhang@spreadtrum.com>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Reviewed-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e570f6bc
......@@ -1583,6 +1583,24 @@ config SERIAL_MEN_Z135
This driver can also be build as a module. If so, the module will be called
men_z135_uart.ko
config SERIAL_SPRD
tristate "Support for Spreadtrum serial"
depends on ARCH_SPRD
select SERIAL_CORE
help
This enables the driver for the Spreadtrum's serial.
config SERIAL_SPRD_CONSOLE
bool "Spreadtrum UART console support"
depends on SERIAL_SPRD=y
select SERIAL_CORE_CONSOLE
select SERIAL_EARLYCON
help
Support for early debug console using Spreadtrum's serial. This enables
the console before standard serial driver is probed. This is enabled
with "earlycon" on the kernel command line. The console is
enabled when early_param is processed.
endmenu
config SERIAL_MCTRL_GPIO
......
......@@ -93,6 +93,7 @@ obj-$(CONFIG_SERIAL_RP2) += rp2.o
obj-$(CONFIG_SERIAL_FSL_LPUART) += fsl_lpuart.o
obj-$(CONFIG_SERIAL_CONEXANT_DIGICOLOR) += digicolor-usart.o
obj-$(CONFIG_SERIAL_MEN_Z135) += men_z135_uart.o
obj-$(CONFIG_SERIAL_SPRD) += sprd_serial.o
# GPIOLIB helpers for modem control lines
obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
/*
* Copyright (C) 2012-2015 Spreadtrum Communications Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#if defined(CONFIG_SERIAL_SPRD_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
#include <linux/clk.h>
#include <linux/console.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
/* device name */
#define UART_NR_MAX 8
#define SPRD_TTY_NAME "ttyS"
#define SPRD_FIFO_SIZE 128
#define SPRD_DEF_RATE 26000000
#define SPRD_BAUD_IO_LIMIT 3000000
#define SPRD_TIMEOUT 256
/* the offset of serial registers and BITs for them */
/* data registers */
#define SPRD_TXD 0x0000
#define SPRD_RXD 0x0004
/* line status register and its BITs */
#define SPRD_LSR 0x0008
#define SPRD_LSR_OE BIT(4)
#define SPRD_LSR_FE BIT(3)
#define SPRD_LSR_PE BIT(2)
#define SPRD_LSR_BI BIT(7)
#define SPRD_LSR_TX_OVER BIT(15)
/* data number in TX and RX fifo */
#define SPRD_STS1 0x000C
/* interrupt enable register and its BITs */
#define SPRD_IEN 0x0010
#define SPRD_IEN_RX_FULL BIT(0)
#define SPRD_IEN_TX_EMPTY BIT(1)
#define SPRD_IEN_BREAK_DETECT BIT(7)
#define SPRD_IEN_TIMEOUT BIT(13)
/* interrupt clear register */
#define SPRD_ICLR 0x0014
/* line control register */
#define SPRD_LCR 0x0018
#define SPRD_LCR_STOP_1BIT 0x10
#define SPRD_LCR_STOP_2BIT 0x30
#define SPRD_LCR_DATA_LEN (BIT(2) | BIT(3))
#define SPRD_LCR_DATA_LEN5 0x0
#define SPRD_LCR_DATA_LEN6 0x4
#define SPRD_LCR_DATA_LEN7 0x8
#define SPRD_LCR_DATA_LEN8 0xc
#define SPRD_LCR_PARITY (BIT(0) | BIT(1))
#define SPRD_LCR_PARITY_EN 0x2
#define SPRD_LCR_EVEN_PAR 0x0
#define SPRD_LCR_ODD_PAR 0x1
/* control register 1 */
#define SPRD_CTL1 0x001C
#define RX_HW_FLOW_CTL_THLD BIT(6)
#define RX_HW_FLOW_CTL_EN BIT(7)
#define TX_HW_FLOW_CTL_EN BIT(8)
#define RX_TOUT_THLD_DEF 0x3E00
#define RX_HFC_THLD_DEF 0x40
/* fifo threshold register */
#define SPRD_CTL2 0x0020
#define THLD_TX_EMPTY 0x40
#define THLD_RX_FULL 0x40
/* config baud rate register */
#define SPRD_CLKD0 0x0024
#define SPRD_CLKD1 0x0028
/* interrupt mask status register */
#define SPRD_IMSR 0x002C
#define SPRD_IMSR_RX_FIFO_FULL BIT(0)
#define SPRD_IMSR_TX_FIFO_EMPTY BIT(1)
#define SPRD_IMSR_BREAK_DETECT BIT(7)
#define SPRD_IMSR_TIMEOUT BIT(13)
struct reg_backup {
u32 ien;
u32 ctrl0;
u32 ctrl1;
u32 ctrl2;
u32 clkd0;
u32 clkd1;
u32 dspwait;
};
struct sprd_uart_port {
struct uart_port port;
struct reg_backup reg_bak;
char name[16];
};
static struct sprd_uart_port *sprd_port[UART_NR_MAX];
static int sprd_ports_num;
static inline unsigned int serial_in(struct uart_port *port, int offset)
{
return readl_relaxed(port->membase + offset);
}
static inline void serial_out(struct uart_port *port, int offset, int value)
{
writel_relaxed(value, port->membase + offset);
}
static unsigned int sprd_tx_empty(struct uart_port *port)
{
if (serial_in(port, SPRD_STS1) & 0xff00)
return 0;
else
return TIOCSER_TEMT;
}
static unsigned int sprd_get_mctrl(struct uart_port *port)
{
return TIOCM_DSR | TIOCM_CTS;
}
static void sprd_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
/* nothing to do */
}
static void sprd_stop_tx(struct uart_port *port)
{
unsigned int ien, iclr;
iclr = serial_in(port, SPRD_ICLR);
ien = serial_in(port, SPRD_IEN);
iclr |= SPRD_IEN_TX_EMPTY;
ien &= ~SPRD_IEN_TX_EMPTY;
serial_out(port, SPRD_ICLR, iclr);
serial_out(port, SPRD_IEN, ien);
}
static void sprd_start_tx(struct uart_port *port)
{
unsigned int ien;
ien = serial_in(port, SPRD_IEN);
if (!(ien & SPRD_IEN_TX_EMPTY)) {
ien |= SPRD_IEN_TX_EMPTY;
serial_out(port, SPRD_IEN, ien);
}
}
static void sprd_stop_rx(struct uart_port *port)
{
unsigned int ien, iclr;
iclr = serial_in(port, SPRD_ICLR);
ien = serial_in(port, SPRD_IEN);
ien &= ~(SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT);
iclr |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT;
serial_out(port, SPRD_IEN, ien);
serial_out(port, SPRD_ICLR, iclr);
}
/* The Sprd serial does not support this function. */
static void sprd_break_ctl(struct uart_port *port, int break_state)
{
/* nothing to do */
}
static int handle_lsr_errors(struct uart_port *port,
unsigned int *flag,
unsigned int *lsr)
{
int ret = 0;
/* statistics */
if (*lsr & SPRD_LSR_BI) {
*lsr &= ~(SPRD_LSR_FE | SPRD_LSR_PE);
port->icount.brk++;
ret = uart_handle_break(port);
if (ret)
return ret;
} else if (*lsr & SPRD_LSR_PE)
port->icount.parity++;
else if (*lsr & SPRD_LSR_FE)
port->icount.frame++;
if (*lsr & SPRD_LSR_OE)
port->icount.overrun++;
/* mask off conditions which should be ignored */
*lsr &= port->read_status_mask;
if (*lsr & SPRD_LSR_BI)
*flag = TTY_BREAK;
else if (*lsr & SPRD_LSR_PE)
*flag = TTY_PARITY;
else if (*lsr & SPRD_LSR_FE)
*flag = TTY_FRAME;
return ret;
}
static inline void sprd_rx(struct uart_port *port)
{
struct tty_port *tty = &port->state->port;
unsigned int ch, flag, lsr, max_count = SPRD_TIMEOUT;
while ((serial_in(port, SPRD_STS1) & 0x00ff) && max_count--) {
lsr = serial_in(port, SPRD_LSR);
ch = serial_in(port, SPRD_RXD);
flag = TTY_NORMAL;
port->icount.rx++;
if (lsr & (SPRD_LSR_BI | SPRD_LSR_PE |
SPRD_LSR_FE | SPRD_LSR_OE))
if (handle_lsr_errors(port, &lsr, &flag))
continue;
if (uart_handle_sysrq_char(port, ch))
continue;
uart_insert_char(port, lsr, SPRD_LSR_OE, ch, flag);
}
tty_flip_buffer_push(tty);
}
static inline void sprd_tx(struct uart_port *port)
{
struct circ_buf *xmit = &port->state->xmit;
int count;
if (port->x_char) {
serial_out(port, SPRD_TXD, port->x_char);
port->icount.tx++;
port->x_char = 0;
return;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
sprd_stop_tx(port);
return;
}
count = THLD_TX_EMPTY;
do {
serial_out(port, SPRD_TXD, xmit->buf[xmit->tail]);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
if (uart_circ_empty(xmit))
break;
} while (--count > 0);
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
if (uart_circ_empty(xmit))
sprd_stop_tx(port);
}
/* this handles the interrupt from one port */
static irqreturn_t sprd_handle_irq(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
unsigned int ims;
spin_lock(&port->lock);
ims = serial_in(port, SPRD_IMSR);
if (!ims)
return IRQ_NONE;
serial_out(port, SPRD_ICLR, ~0);
if (ims & (SPRD_IMSR_RX_FIFO_FULL |
SPRD_IMSR_BREAK_DETECT | SPRD_IMSR_TIMEOUT))
sprd_rx(port);
if (ims & SPRD_IMSR_TX_FIFO_EMPTY)
sprd_tx(port);
spin_unlock(&port->lock);
return IRQ_HANDLED;
}
static int sprd_startup(struct uart_port *port)
{
int ret = 0;
unsigned int ien, fc;
unsigned int timeout;
struct sprd_uart_port *sp;
unsigned long flags;
serial_out(port, SPRD_CTL2, ((THLD_TX_EMPTY << 8) | THLD_RX_FULL));
/* clear rx fifo */
timeout = SPRD_TIMEOUT;
while (timeout-- && serial_in(port, SPRD_STS1) & 0x00ff)
serial_in(port, SPRD_RXD);
/* clear tx fifo */
timeout = SPRD_TIMEOUT;
while (timeout-- && serial_in(port, SPRD_STS1) & 0xff00)
cpu_relax();
/* clear interrupt */
serial_out(port, SPRD_IEN, 0);
serial_out(port, SPRD_ICLR, ~0);
/* allocate irq */
sp = container_of(port, struct sprd_uart_port, port);
snprintf(sp->name, sizeof(sp->name), "sprd_serial%d", port->line);
ret = devm_request_irq(port->dev, port->irq, sprd_handle_irq,
IRQF_SHARED, sp->name, port);
if (ret) {
dev_err(port->dev, "fail to request serial irq %d, ret=%d\n",
port->irq, ret);
return ret;
}
fc = serial_in(port, SPRD_CTL1);
fc |= RX_TOUT_THLD_DEF | RX_HFC_THLD_DEF;
serial_out(port, SPRD_CTL1, fc);
/* enable interrupt */
spin_lock_irqsave(&port->lock, flags);
ien = serial_in(port, SPRD_IEN);
ien |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT | SPRD_IEN_TIMEOUT;
serial_out(port, SPRD_IEN, ien);
spin_unlock_irqrestore(&port->lock, flags);
return 0;
}
static void sprd_shutdown(struct uart_port *port)
{
serial_out(port, SPRD_IEN, 0);
serial_out(port, SPRD_ICLR, ~0);
devm_free_irq(port->dev, port->irq, port);
}
static void sprd_set_termios(struct uart_port *port,
struct ktermios *termios,
struct ktermios *old)
{
unsigned int baud, quot;
unsigned int lcr = 0, fc;
unsigned long flags;
/* ask the core to calculate the divisor for us */
baud = uart_get_baud_rate(port, termios, old, 0, SPRD_BAUD_IO_LIMIT);
quot = (unsigned int)((port->uartclk + baud / 2) / baud);
/* set data length */
switch (termios->c_cflag & CSIZE) {
case CS5:
lcr |= SPRD_LCR_DATA_LEN5;
break;
case CS6:
lcr |= SPRD_LCR_DATA_LEN6;
break;
case CS7:
lcr |= SPRD_LCR_DATA_LEN7;
break;
case CS8:
default:
lcr |= SPRD_LCR_DATA_LEN8;
break;
}
/* calculate stop bits */
lcr &= ~(SPRD_LCR_STOP_1BIT | SPRD_LCR_STOP_2BIT);
if (termios->c_cflag & CSTOPB)
lcr |= SPRD_LCR_STOP_2BIT;
else
lcr |= SPRD_LCR_STOP_1BIT;
/* calculate parity */
lcr &= ~SPRD_LCR_PARITY;
termios->c_cflag &= ~CMSPAR; /* no support mark/space */
if (termios->c_cflag & PARENB) {
lcr |= SPRD_LCR_PARITY_EN;
if (termios->c_cflag & PARODD)
lcr |= SPRD_LCR_ODD_PAR;
else
lcr |= SPRD_LCR_EVEN_PAR;
}
spin_lock_irqsave(&port->lock, flags);
/* update the per-port timeout */
uart_update_timeout(port, termios->c_cflag, baud);
port->read_status_mask = SPRD_LSR_OE;
if (termios->c_iflag & INPCK)
port->read_status_mask |= SPRD_LSR_FE | SPRD_LSR_PE;
if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
port->read_status_mask |= SPRD_LSR_BI;
/* characters to ignore */
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= SPRD_LSR_PE | SPRD_LSR_FE;
if (termios->c_iflag & IGNBRK) {
port->ignore_status_mask |= SPRD_LSR_BI;
/*
* If we're ignoring parity and break indicators,
* ignore overruns too (for real raw support).
*/
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= SPRD_LSR_OE;
}
/* flow control */
fc = serial_in(port, SPRD_CTL1);
fc &= ~(RX_HW_FLOW_CTL_THLD | RX_HW_FLOW_CTL_EN | TX_HW_FLOW_CTL_EN);
if (termios->c_cflag & CRTSCTS) {
fc |= RX_HW_FLOW_CTL_THLD;
fc |= RX_HW_FLOW_CTL_EN;
fc |= TX_HW_FLOW_CTL_EN;
}
/* clock divider bit0~bit15 */
serial_out(port, SPRD_CLKD0, quot & 0xffff);
/* clock divider bit16~bit20 */
serial_out(port, SPRD_CLKD1, (quot & 0x1f0000) >> 16);
serial_out(port, SPRD_LCR, lcr);
fc |= RX_TOUT_THLD_DEF | RX_HFC_THLD_DEF;
serial_out(port, SPRD_CTL1, fc);
spin_unlock_irqrestore(&port->lock, flags);
/* Don't rewrite B0 */
if (tty_termios_baud_rate(termios))
tty_termios_encode_baud_rate(termios, baud, baud);
}
static const char *sprd_type(struct uart_port *port)
{
return "SPX";
}
static void sprd_release_port(struct uart_port *port)
{
/* nothing to do */
}
static int sprd_request_port(struct uart_port *port)
{
return 0;
}
static void sprd_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE)
port->type = PORT_SPRD;
}
static int sprd_verify_port(struct uart_port *port,
struct serial_struct *ser)
{
if (ser->type != PORT_SPRD)
return -EINVAL;
if (port->irq != ser->irq)
return -EINVAL;
return 0;
}
static struct uart_ops serial_sprd_ops = {
.tx_empty = sprd_tx_empty,
.get_mctrl = sprd_get_mctrl,
.set_mctrl = sprd_set_mctrl,
.stop_tx = sprd_stop_tx,
.start_tx = sprd_start_tx,
.stop_rx = sprd_stop_rx,
.break_ctl = sprd_break_ctl,
.startup = sprd_startup,
.shutdown = sprd_shutdown,
.set_termios = sprd_set_termios,
.type = sprd_type,
.release_port = sprd_release_port,
.request_port = sprd_request_port,
.config_port = sprd_config_port,
.verify_port = sprd_verify_port,
};
#ifdef CONFIG_SERIAL_SPRD_CONSOLE
static inline void wait_for_xmitr(struct uart_port *port)
{
unsigned int status, tmout = 10000;
/* wait up to 10ms for the character(s) to be sent */
do {
status = serial_in(port, SPRD_STS1);
if (--tmout == 0)
break;
udelay(1);
} while (status & 0xff00);
}
static void sprd_console_putchar(struct uart_port *port, int ch)
{
wait_for_xmitr(port);
serial_out(port, SPRD_TXD, ch);
}
static void sprd_console_write(struct console *co, const char *s,
unsigned int count)
{
struct uart_port *port = &sprd_port[co->index]->port;
int locked = 1;
unsigned long flags;
if (port->sysrq)
locked = 0;
else if (oops_in_progress)
locked = spin_trylock_irqsave(&port->lock, flags);
else
spin_lock_irqsave(&port->lock, flags);
uart_console_write(port, s, count, sprd_console_putchar);
/* wait for transmitter to become empty */
wait_for_xmitr(port);
if (locked)
spin_unlock_irqrestore(&port->lock, flags);
}
static int __init sprd_console_setup(struct console *co, char *options)
{
struct uart_port *port;
int baud = 115200;
int bits = 8;
int parity = 'n';
int flow = 'n';
if (co->index >= UART_NR_MAX || co->index < 0)
co->index = 0;
port = &sprd_port[co->index]->port;
if (port == NULL) {
pr_info("serial port %d not yet initialized\n", co->index);
return -ENODEV;
}
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(port, co, baud, parity, bits, flow);
}
static struct uart_driver sprd_uart_driver;
static struct console sprd_console = {