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linux/drivers/tty/serial/8250/8250_fintek.c
Ji-Ze Hong (Peter Hong) 07a708f0a1 serial: 8250_fintek: Fix crash with baud rate B0 
The 8250_fintek.c is support the Fintek F81866/F81216 with dynamic clock.
But It'll generate "division by zero" exception and crash in
fintek_8250_set_termios() with baud rate 0 on baudrate_table[i] % baud.

It can be tested with following C code:

	...
	struct termios options;

	tcgetattr(fd, &options);
	...
	options.c_cflag = CS8 | CREAD; /* baud rate 0 */
	tcsetattr(fd, TCSANOW, &options);
	tcflush(fd, TCIOFLUSH);

Fixes: 195638b6d4 ("serial: 8250_fintek: UART dynamic clocksource on Fintek F81866")
Reported-by: Lukas Redlinger <rel+kernel@agilox.net>
Cc: Lukas Redlinger <rel+kernel@agilox.net>
Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-08 13:09:35 +01:00

474 lines
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// SPDX-License-Identifier: GPL-2.0
/*
* Probe for F81216A LPC to 4 UART
*
* Copyright (C) 2014-2016 Ricardo Ribalda, Qtechnology A/S
*/
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pnp.h>
#include <linux/kernel.h>
#include <linux/serial_core.h>
#include <linux/irq.h>
#include "8250.h"
#define ADDR_PORT 0
#define DATA_PORT 1
#define EXIT_KEY 0xAA
#define CHIP_ID1 0x20
#define CHIP_ID2 0x21
#define CHIP_ID_F81865 0x0407
#define CHIP_ID_F81866 0x1010
#define CHIP_ID_F81216AD 0x1602
#define CHIP_ID_F81216H 0x0501
#define CHIP_ID_F81216 0x0802
#define VENDOR_ID1 0x23
#define VENDOR_ID1_VAL 0x19
#define VENDOR_ID2 0x24
#define VENDOR_ID2_VAL 0x34
#define IO_ADDR1 0x61
#define IO_ADDR2 0x60
#define LDN 0x7
#define FINTEK_IRQ_MODE 0x70
#define IRQ_SHARE BIT(4)
#define IRQ_MODE_MASK (BIT(6) | BIT(5))
#define IRQ_LEVEL_LOW 0
#define IRQ_EDGE_HIGH BIT(5)
/*
* F81216H clock source register, the value and mask is the same with F81866,
* but it's on F0h.
*
* Clock speeds for UART (register F0h)
* 00: 1.8432MHz.
* 01: 18.432MHz.
* 10: 24MHz.
* 11: 14.769MHz.
*/
#define RS485 0xF0
#define RTS_INVERT BIT(5)
#define RS485_URA BIT(4)
#define RXW4C_IRA BIT(3)
#define TXW4C_IRA BIT(2)
#define FIFO_CTRL 0xF6
#define FIFO_MODE_MASK (BIT(1) | BIT(0))
#define FIFO_MODE_128 (BIT(1) | BIT(0))
#define RXFTHR_MODE_MASK (BIT(5) | BIT(4))
#define RXFTHR_MODE_4X BIT(5)
#define F81216_LDN_LOW 0x0
#define F81216_LDN_HIGH 0x4
/*
* F81866 registers
*
* The IRQ setting mode of F81866 is not the same with F81216 series.
* Level/Low: IRQ_MODE0:0, IRQ_MODE1:0
* Edge/High: IRQ_MODE0:1, IRQ_MODE1:0
*
* Clock speeds for UART (register F2h)
* 00: 1.8432MHz.
* 01: 18.432MHz.
* 10: 24MHz.
* 11: 14.769MHz.
*/
#define F81866_IRQ_MODE 0xf0
#define F81866_IRQ_SHARE BIT(0)
#define F81866_IRQ_MODE0 BIT(1)
#define F81866_FIFO_CTRL FIFO_CTRL
#define F81866_IRQ_MODE1 BIT(3)
#define F81866_LDN_LOW 0x10
#define F81866_LDN_HIGH 0x16
#define F81866_UART_CLK 0xF2
#define F81866_UART_CLK_MASK (BIT(1) | BIT(0))
#define F81866_UART_CLK_1_8432MHZ 0
#define F81866_UART_CLK_14_769MHZ (BIT(1) | BIT(0))
#define F81866_UART_CLK_18_432MHZ BIT(0)
#define F81866_UART_CLK_24MHZ BIT(1)
struct fintek_8250 {
u16 pid;
u16 base_port;
u8 index;
u8 key;
};
static u8 sio_read_reg(struct fintek_8250 *pdata, u8 reg)
{
outb(reg, pdata->base_port + ADDR_PORT);
return inb(pdata->base_port + DATA_PORT);
}
static void sio_write_reg(struct fintek_8250 *pdata, u8 reg, u8 data)
{
outb(reg, pdata->base_port + ADDR_PORT);
outb(data, pdata->base_port + DATA_PORT);
}
static void sio_write_mask_reg(struct fintek_8250 *pdata, u8 reg, u8 mask,
u8 data)
{
u8 tmp;
tmp = (sio_read_reg(pdata, reg) & ~mask) | (mask & data);
sio_write_reg(pdata, reg, tmp);
}
static int fintek_8250_enter_key(u16 base_port, u8 key)
{
if (!request_muxed_region(base_port, 2, "8250_fintek"))
return -EBUSY;
/* Force to deactive all SuperIO in this base_port */
outb(EXIT_KEY, base_port + ADDR_PORT);
outb(key, base_port + ADDR_PORT);
outb(key, base_port + ADDR_PORT);
return 0;
}
static void fintek_8250_exit_key(u16 base_port)
{
outb(EXIT_KEY, base_port + ADDR_PORT);
release_region(base_port + ADDR_PORT, 2);
}
static int fintek_8250_check_id(struct fintek_8250 *pdata)
{
u16 chip;
if (sio_read_reg(pdata, VENDOR_ID1) != VENDOR_ID1_VAL)
return -ENODEV;
if (sio_read_reg(pdata, VENDOR_ID2) != VENDOR_ID2_VAL)
return -ENODEV;
chip = sio_read_reg(pdata, CHIP_ID1);
chip |= sio_read_reg(pdata, CHIP_ID2) << 8;
switch (chip) {
case CHIP_ID_F81865:
case CHIP_ID_F81866:
case CHIP_ID_F81216AD:
case CHIP_ID_F81216H:
case CHIP_ID_F81216:
break;
default:
return -ENODEV;
}
pdata->pid = chip;
return 0;
}
static int fintek_8250_get_ldn_range(struct fintek_8250 *pdata, int *min,
int *max)
{
switch (pdata->pid) {
case CHIP_ID_F81865:
case CHIP_ID_F81866:
*min = F81866_LDN_LOW;
*max = F81866_LDN_HIGH;
return 0;
case CHIP_ID_F81216AD:
case CHIP_ID_F81216H:
case CHIP_ID_F81216:
*min = F81216_LDN_LOW;
*max = F81216_LDN_HIGH;
return 0;
}
return -ENODEV;
}
static int fintek_8250_rs485_config(struct uart_port *port,
struct serial_rs485 *rs485)
{
uint8_t config = 0;
struct fintek_8250 *pdata = port->private_data;
if (!pdata)
return -EINVAL;
/* Hardware do not support same RTS level on send and receive */
if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
!(rs485->flags & SER_RS485_RTS_AFTER_SEND))
return -EINVAL;
if (rs485->flags & SER_RS485_ENABLED) {
memset(rs485->padding, 0, sizeof(rs485->padding));
config |= RS485_URA;
} else {
memset(rs485, 0, sizeof(*rs485));
}
rs485->flags &= SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND |
SER_RS485_RTS_AFTER_SEND;
/* Only the first port supports delays */
if (pdata->index) {
rs485->delay_rts_before_send = 0;
rs485->delay_rts_after_send = 0;
}
if (rs485->delay_rts_before_send) {
rs485->delay_rts_before_send = 1;
config |= TXW4C_IRA;
}
if (rs485->delay_rts_after_send) {
rs485->delay_rts_after_send = 1;
config |= RXW4C_IRA;
}
if (rs485->flags & SER_RS485_RTS_ON_SEND)
config |= RTS_INVERT;
if (fintek_8250_enter_key(pdata->base_port, pdata->key))
return -EBUSY;
sio_write_reg(pdata, LDN, pdata->index);
sio_write_reg(pdata, RS485, config);
fintek_8250_exit_key(pdata->base_port);
port->rs485 = *rs485;
return 0;
}
static void fintek_8250_set_irq_mode(struct fintek_8250 *pdata, bool is_level)
{
sio_write_reg(pdata, LDN, pdata->index);
switch (pdata->pid) {
case CHIP_ID_F81866:
sio_write_mask_reg(pdata, F81866_FIFO_CTRL, F81866_IRQ_MODE1,
0);
/* fall through */
case CHIP_ID_F81865:
sio_write_mask_reg(pdata, F81866_IRQ_MODE, F81866_IRQ_SHARE,
F81866_IRQ_SHARE);
sio_write_mask_reg(pdata, F81866_IRQ_MODE, F81866_IRQ_MODE0,
is_level ? 0 : F81866_IRQ_MODE0);
break;
case CHIP_ID_F81216AD:
case CHIP_ID_F81216H:
case CHIP_ID_F81216:
sio_write_mask_reg(pdata, FINTEK_IRQ_MODE, IRQ_SHARE,
IRQ_SHARE);
sio_write_mask_reg(pdata, FINTEK_IRQ_MODE, IRQ_MODE_MASK,
is_level ? IRQ_LEVEL_LOW : IRQ_EDGE_HIGH);
break;
}
}
static void fintek_8250_set_max_fifo(struct fintek_8250 *pdata)
{
switch (pdata->pid) {
case CHIP_ID_F81216H: /* 128Bytes FIFO */
case CHIP_ID_F81866:
sio_write_mask_reg(pdata, FIFO_CTRL,
FIFO_MODE_MASK | RXFTHR_MODE_MASK,
FIFO_MODE_128 | RXFTHR_MODE_4X);
break;
default: /* Default 16Bytes FIFO */
break;
}
}
static void fintek_8250_goto_highspeed(struct uart_8250_port *uart,
struct fintek_8250 *pdata)
{
sio_write_reg(pdata, LDN, pdata->index);
switch (pdata->pid) {
case CHIP_ID_F81866: /* set uart clock for high speed serial mode */
sio_write_mask_reg(pdata, F81866_UART_CLK,
F81866_UART_CLK_MASK,
F81866_UART_CLK_14_769MHZ);
uart->port.uartclk = 921600 * 16;
break;
default: /* leave clock speed untouched */
break;
}
}
void fintek_8250_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
{
struct fintek_8250 *pdata = port->private_data;
unsigned int baud = tty_termios_baud_rate(termios);
int i;
u8 reg;
static u32 baudrate_table[] = {115200, 921600, 1152000, 1500000};
static u8 clock_table[] = { F81866_UART_CLK_1_8432MHZ,
F81866_UART_CLK_14_769MHZ, F81866_UART_CLK_18_432MHZ,
F81866_UART_CLK_24MHZ };
/*
* We'll use serial8250_do_set_termios() for baud = 0, otherwise It'll
* crash on baudrate_table[i] % baud with "division by zero".
*/
if (!baud)
goto exit;
switch (pdata->pid) {
case CHIP_ID_F81216H:
reg = RS485;
break;
case CHIP_ID_F81866:
reg = F81866_UART_CLK;
break;
default:
/* Don't change clocksource with unknown PID */
dev_warn(port->dev,
"%s: pid: %x Not support. use default set_termios.\n",
__func__, pdata->pid);
goto exit;
}
for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
if (baud > baudrate_table[i] || baudrate_table[i] % baud != 0)
continue;
if (port->uartclk == baudrate_table[i] * 16)
break;
if (fintek_8250_enter_key(pdata->base_port, pdata->key))
continue;
port->uartclk = baudrate_table[i] * 16;
sio_write_reg(pdata, LDN, pdata->index);
sio_write_mask_reg(pdata, reg, F81866_UART_CLK_MASK,
clock_table[i]);
fintek_8250_exit_key(pdata->base_port);
break;
}
if (i == ARRAY_SIZE(baudrate_table)) {
baud = tty_termios_baud_rate(old);
tty_termios_encode_baud_rate(termios, baud, baud);
}
exit:
serial8250_do_set_termios(port, termios, old);
}
static void fintek_8250_set_termios_handler(struct uart_8250_port *uart)
{
struct fintek_8250 *pdata = uart->port.private_data;
switch (pdata->pid) {
case CHIP_ID_F81216H:
case CHIP_ID_F81866:
uart->port.set_termios = fintek_8250_set_termios;
break;
default:
break;
}
}
static int probe_setup_port(struct fintek_8250 *pdata,
struct uart_8250_port *uart)
{
static const u16 addr[] = {0x4e, 0x2e};
static const u8 keys[] = {0x77, 0xa0, 0x87, 0x67};
struct irq_data *irq_data;
bool level_mode = false;
int i, j, k, min, max;
for (i = 0; i < ARRAY_SIZE(addr); i++) {
for (j = 0; j < ARRAY_SIZE(keys); j++) {
pdata->base_port = addr[i];
pdata->key = keys[j];
if (fintek_8250_enter_key(addr[i], keys[j]))
continue;
if (fintek_8250_check_id(pdata) ||
fintek_8250_get_ldn_range(pdata, &min, &max)) {
fintek_8250_exit_key(addr[i]);
continue;
}
for (k = min; k < max; k++) {
u16 aux;
sio_write_reg(pdata, LDN, k);
aux = sio_read_reg(pdata, IO_ADDR1);
aux |= sio_read_reg(pdata, IO_ADDR2) << 8;
if (aux != uart->port.iobase)
continue;
pdata->index = k;
irq_data = irq_get_irq_data(uart->port.irq);
if (irq_data)
level_mode =
irqd_is_level_type(irq_data);
fintek_8250_set_irq_mode(pdata, level_mode);
fintek_8250_set_max_fifo(pdata);
fintek_8250_goto_highspeed(uart, pdata);
fintek_8250_exit_key(addr[i]);
return 0;
}
fintek_8250_exit_key(addr[i]);
}
}
return -ENODEV;
}
static void fintek_8250_set_rs485_handler(struct uart_8250_port *uart)
{
struct fintek_8250 *pdata = uart->port.private_data;
switch (pdata->pid) {
case CHIP_ID_F81216AD:
case CHIP_ID_F81216H:
case CHIP_ID_F81866:
case CHIP_ID_F81865:
uart->port.rs485_config = fintek_8250_rs485_config;
break;
default: /* No RS485 Auto direction functional */
break;
}
}
int fintek_8250_probe(struct uart_8250_port *uart)
{
struct fintek_8250 *pdata;
struct fintek_8250 probe_data;
if (probe_setup_port(&probe_data, uart))
return -ENODEV;
pdata = devm_kzalloc(uart->port.dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
memcpy(pdata, &probe_data, sizeof(probe_data));
uart->port.private_data = pdata;
fintek_8250_set_rs485_handler(uart);
fintek_8250_set_termios_handler(uart);
return 0;
}
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