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kernel-fxtec-pro1x/drivers/net/can/sja1000/peak_pcmcia.c
Jia-Ju Bai c8d4dea2a8 can: sja1000: Replace mdelay with usleep_range in pcan_add_channels 
pcan_add_channels() is never called in atomic context.

pcan_add_channels() is only called by pcan_probe(), which is only set as
".probe" in struct pcmcia_driver.

Despite never getting called from atomic context, pcan_add_channels()
calls mdelay() to busily wait.
This is not necessary and can be replaced with usleep_range() to
avoid busy waiting.

This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2018-07-27 10:40:17 +02:00

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/*
* Copyright (C) 2010-2012 Stephane Grosjean <s.grosjean@peak-system.com>
*
* CAN driver for PEAK-System PCAN-PC Card
* Derived from the PCAN project file driver/src/pcan_pccard.c
* Copyright (C) 2006-2010 PEAK System-Technik GmbH
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the version 2 of the GNU General Public License
* as published by the Free Software Foundation
*
* 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.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/netdevice.h>
#include <linux/delay.h>
#include <linux/timer.h>
#include <linux/io.h>
#include <pcmcia/cistpl.h>
#include <pcmcia/ds.h>
#include <linux/can.h>
#include <linux/can/dev.h>
#include "sja1000.h"
MODULE_AUTHOR("Stephane Grosjean <s.grosjean@peak-system.com>");
MODULE_DESCRIPTION("CAN driver for PEAK-System PCAN-PC Cards");
MODULE_LICENSE("GPL v2");
MODULE_SUPPORTED_DEVICE("PEAK PCAN-PC Card");
/* PEAK-System PCMCIA driver name */
#define PCC_NAME "peak_pcmcia"
#define PCC_CHAN_MAX 2
#define PCC_CAN_CLOCK (16000000 / 2)
#define PCC_MANF_ID 0x0377
#define PCC_CARD_ID 0x0001
#define PCC_CHAN_SIZE 0x20
#define PCC_CHAN_OFF(c) ((c) * PCC_CHAN_SIZE)
#define PCC_COMN_OFF (PCC_CHAN_OFF(PCC_CHAN_MAX))
#define PCC_COMN_SIZE 0x40
/* common area registers */
#define PCC_CCR 0x00
#define PCC_CSR 0x02
#define PCC_CPR 0x04
#define PCC_SPI_DIR 0x06
#define PCC_SPI_DOR 0x08
#define PCC_SPI_ADR 0x0a
#define PCC_SPI_IR 0x0c
#define PCC_FW_MAJOR 0x10
#define PCC_FW_MINOR 0x12
/* CCR bits */
#define PCC_CCR_CLK_16 0x00
#define PCC_CCR_CLK_10 0x01
#define PCC_CCR_CLK_21 0x02
#define PCC_CCR_CLK_8 0x03
#define PCC_CCR_CLK_MASK PCC_CCR_CLK_8
#define PCC_CCR_RST_CHAN(c) (0x01 << ((c) + 2))
#define PCC_CCR_RST_ALL (PCC_CCR_RST_CHAN(0) | PCC_CCR_RST_CHAN(1))
#define PCC_CCR_RST_MASK PCC_CCR_RST_ALL
/* led selection bits */
#define PCC_LED(c) (1 << (c))
#define PCC_LED_ALL (PCC_LED(0) | PCC_LED(1))
/* led state value */
#define PCC_LED_ON 0x00
#define PCC_LED_FAST 0x01
#define PCC_LED_SLOW 0x02
#define PCC_LED_OFF 0x03
#define PCC_CCR_LED_CHAN(s, c) ((s) << (((c) + 2) << 1))
#define PCC_CCR_LED_ON_CHAN(c) PCC_CCR_LED_CHAN(PCC_LED_ON, c)
#define PCC_CCR_LED_FAST_CHAN(c) PCC_CCR_LED_CHAN(PCC_LED_FAST, c)
#define PCC_CCR_LED_SLOW_CHAN(c) PCC_CCR_LED_CHAN(PCC_LED_SLOW, c)
#define PCC_CCR_LED_OFF_CHAN(c) PCC_CCR_LED_CHAN(PCC_LED_OFF, c)
#define PCC_CCR_LED_MASK_CHAN(c) PCC_CCR_LED_OFF_CHAN(c)
#define PCC_CCR_LED_OFF_ALL (PCC_CCR_LED_OFF_CHAN(0) | \
PCC_CCR_LED_OFF_CHAN(1))
#define PCC_CCR_LED_MASK PCC_CCR_LED_OFF_ALL
#define PCC_CCR_INIT (PCC_CCR_CLK_16 | PCC_CCR_RST_ALL | PCC_CCR_LED_OFF_ALL)
/* CSR bits */
#define PCC_CSR_SPI_BUSY 0x04
/* time waiting for SPI busy (prevent from infinite loop) */
#define PCC_SPI_MAX_BUSY_WAIT_MS 3
/* max count of reading the SPI status register waiting for a change */
/* (prevent from infinite loop) */
#define PCC_WRITE_MAX_LOOP 1000
/* max nb of int handled by that isr in one shot (prevent from infinite loop) */
#define PCC_ISR_MAX_LOOP 10
/* EEPROM chip instruction set */
/* note: EEPROM Read/Write instructions include A8 bit */
#define PCC_EEP_WRITE(a) (0x02 | (((a) & 0x100) >> 5))
#define PCC_EEP_READ(a) (0x03 | (((a) & 0x100) >> 5))
#define PCC_EEP_WRDI 0x04 /* EEPROM Write Disable */
#define PCC_EEP_RDSR 0x05 /* EEPROM Read Status Register */
#define PCC_EEP_WREN 0x06 /* EEPROM Write Enable */
/* EEPROM Status Register bits */
#define PCC_EEP_SR_WEN 0x02 /* EEPROM SR Write Enable bit */
#define PCC_EEP_SR_WIP 0x01 /* EEPROM SR Write In Progress bit */
/*
* The board configuration is probably following:
* RX1 is connected to ground.
* TX1 is not connected.
* CLKO is not connected.
* Setting the OCR register to 0xDA is a good idea.
* This means normal output mode, push-pull and the correct polarity.
*/
#define PCC_OCR (OCR_TX0_PUSHPULL | OCR_TX1_PUSHPULL)
/*
* In the CDR register, you should set CBP to 1.
* You will probably also want to set the clock divider value to 7
* (meaning direct oscillator output) because the second SJA1000 chip
* is driven by the first one CLKOUT output.
*/
#define PCC_CDR (CDR_CBP | CDR_CLKOUT_MASK)
struct pcan_channel {
struct net_device *netdev;
unsigned long prev_rx_bytes;
unsigned long prev_tx_bytes;
};
/* PCAN-PC Card private structure */
struct pcan_pccard {
struct pcmcia_device *pdev;
int chan_count;
struct pcan_channel channel[PCC_CHAN_MAX];
u8 ccr;
u8 fw_major;
u8 fw_minor;
void __iomem *ioport_addr;
struct timer_list led_timer;
};
static struct pcmcia_device_id pcan_table[] = {
PCMCIA_DEVICE_MANF_CARD(PCC_MANF_ID, PCC_CARD_ID),
PCMCIA_DEVICE_NULL,
};
MODULE_DEVICE_TABLE(pcmcia, pcan_table);
static void pcan_set_leds(struct pcan_pccard *card, u8 mask, u8 state);
/*
* start timer which controls leds state
*/
static void pcan_start_led_timer(struct pcan_pccard *card)
{
if (!timer_pending(&card->led_timer))
mod_timer(&card->led_timer, jiffies + HZ);
}
/*
* stop the timer which controls leds state
*/
static void pcan_stop_led_timer(struct pcan_pccard *card)
{
del_timer_sync(&card->led_timer);
}
/*
* read a sja1000 register
*/
static u8 pcan_read_canreg(const struct sja1000_priv *priv, int port)
{
return ioread8(priv->reg_base + port);
}
/*
* write a sja1000 register
*/
static void pcan_write_canreg(const struct sja1000_priv *priv, int port, u8 v)
{
struct pcan_pccard *card = priv->priv;
int c = (priv->reg_base - card->ioport_addr) / PCC_CHAN_SIZE;
/* sja1000 register changes control the leds state */
if (port == SJA1000_MOD)
switch (v) {
case MOD_RM:
/* Reset Mode: set led on */
pcan_set_leds(card, PCC_LED(c), PCC_LED_ON);
break;
case 0x00:
/* Normal Mode: led slow blinking and start led timer */
pcan_set_leds(card, PCC_LED(c), PCC_LED_SLOW);
pcan_start_led_timer(card);
break;
default:
break;
}
iowrite8(v, priv->reg_base + port);
}
/*
* read a register from the common area
*/
static u8 pcan_read_reg(struct pcan_pccard *card, int port)
{
return ioread8(card->ioport_addr + PCC_COMN_OFF + port);
}
/*
* write a register into the common area
*/
static void pcan_write_reg(struct pcan_pccard *card, int port, u8 v)
{
/* cache ccr value */
if (port == PCC_CCR) {
if (card->ccr == v)
return;
card->ccr = v;
}
iowrite8(v, card->ioport_addr + PCC_COMN_OFF + port);
}
/*
* check whether the card is present by checking its fw version numbers
* against values read at probing time.
*/
static inline int pcan_pccard_present(struct pcan_pccard *card)
{
return ((pcan_read_reg(card, PCC_FW_MAJOR) == card->fw_major) &&
(pcan_read_reg(card, PCC_FW_MINOR) == card->fw_minor));
}
/*
* wait for SPI engine while it is busy
*/
static int pcan_wait_spi_busy(struct pcan_pccard *card)
{
unsigned long timeout = jiffies +
msecs_to_jiffies(PCC_SPI_MAX_BUSY_WAIT_MS) + 1;
/* be sure to read status at least once after sleeping */
while (pcan_read_reg(card, PCC_CSR) & PCC_CSR_SPI_BUSY) {
if (time_after(jiffies, timeout))
return -EBUSY;
schedule();
}
return 0;
}
/*
* write data in device eeprom
*/
static int pcan_write_eeprom(struct pcan_pccard *card, u16 addr, u8 v)
{
u8 status;
int err, i;
/* write instruction enabling write */
pcan_write_reg(card, PCC_SPI_IR, PCC_EEP_WREN);
err = pcan_wait_spi_busy(card);
if (err)
goto we_spi_err;
/* wait until write enabled */
for (i = 0; i < PCC_WRITE_MAX_LOOP; i++) {
/* write instruction reading the status register */
pcan_write_reg(card, PCC_SPI_IR, PCC_EEP_RDSR);
err = pcan_wait_spi_busy(card);
if (err)
goto we_spi_err;
/* get status register value and check write enable bit */
status = pcan_read_reg(card, PCC_SPI_DIR);
if (status & PCC_EEP_SR_WEN)
break;
}
if (i >= PCC_WRITE_MAX_LOOP) {
dev_err(&card->pdev->dev,
"stop waiting to be allowed to write in eeprom\n");
return -EIO;
}
/* set address and data */
pcan_write_reg(card, PCC_SPI_ADR, addr & 0xff);
pcan_write_reg(card, PCC_SPI_DOR, v);
/*
* write instruction with bit[3] set according to address value:
* if addr refers to upper half of the memory array: bit[3] = 1
*/
pcan_write_reg(card, PCC_SPI_IR, PCC_EEP_WRITE(addr));
err = pcan_wait_spi_busy(card);
if (err)
goto we_spi_err;
/* wait while write in progress */
for (i = 0; i < PCC_WRITE_MAX_LOOP; i++) {
/* write instruction reading the status register */
pcan_write_reg(card, PCC_SPI_IR, PCC_EEP_RDSR);
err = pcan_wait_spi_busy(card);
if (err)
goto we_spi_err;
/* get status register value and check write in progress bit */
status = pcan_read_reg(card, PCC_SPI_DIR);
if (!(status & PCC_EEP_SR_WIP))
break;
}
if (i >= PCC_WRITE_MAX_LOOP) {
dev_err(&card->pdev->dev,
"stop waiting for write in eeprom to complete\n");
return -EIO;
}
/* write instruction disabling write */
pcan_write_reg(card, PCC_SPI_IR, PCC_EEP_WRDI);
err = pcan_wait_spi_busy(card);
if (err)
goto we_spi_err;
return 0;
we_spi_err:
dev_err(&card->pdev->dev,
"stop waiting (spi engine always busy) err %d\n", err);
return err;
}
static void pcan_set_leds(struct pcan_pccard *card, u8 led_mask, u8 state)
{
u8 ccr = card->ccr;
int i;
for (i = 0; i < card->chan_count; i++)
if (led_mask & PCC_LED(i)) {
/* clear corresponding led bits in ccr */
ccr &= ~PCC_CCR_LED_MASK_CHAN(i);
/* then set new bits */
ccr |= PCC_CCR_LED_CHAN(state, i);
}
/* real write only if something has changed in ccr */
pcan_write_reg(card, PCC_CCR, ccr);
}
/*
* enable/disable CAN connectors power
*/
static inline void pcan_set_can_power(struct pcan_pccard *card, int onoff)
{
int err;
err = pcan_write_eeprom(card, 0, !!onoff);
if (err)
dev_err(&card->pdev->dev,
"failed setting power %s to can connectors (err %d)\n",
(onoff) ? "on" : "off", err);
}
/*
* set leds state according to channel activity
*/
static void pcan_led_timer(struct timer_list *t)
{
struct pcan_pccard *card = from_timer(card, t, led_timer);
struct net_device *netdev;
int i, up_count = 0;
u8 ccr;
ccr = card->ccr;
for (i = 0; i < card->chan_count; i++) {
/* default is: not configured */
ccr &= ~PCC_CCR_LED_MASK_CHAN(i);
ccr |= PCC_CCR_LED_ON_CHAN(i);
netdev = card->channel[i].netdev;
if (!netdev || !(netdev->flags & IFF_UP))
continue;
up_count++;
/* no activity (but configured) */
ccr &= ~PCC_CCR_LED_MASK_CHAN(i);
ccr |= PCC_CCR_LED_SLOW_CHAN(i);
/* if bytes counters changed, set fast blinking led */
if (netdev->stats.rx_bytes != card->channel[i].prev_rx_bytes) {
card->channel[i].prev_rx_bytes = netdev->stats.rx_bytes;
ccr &= ~PCC_CCR_LED_MASK_CHAN(i);
ccr |= PCC_CCR_LED_FAST_CHAN(i);
}
if (netdev->stats.tx_bytes != card->channel[i].prev_tx_bytes) {
card->channel[i].prev_tx_bytes = netdev->stats.tx_bytes;
ccr &= ~PCC_CCR_LED_MASK_CHAN(i);
ccr |= PCC_CCR_LED_FAST_CHAN(i);
}
}
/* write the new leds state */
pcan_write_reg(card, PCC_CCR, ccr);
/* restart timer (except if no more configured channels) */
if (up_count)
mod_timer(&card->led_timer, jiffies + HZ);
}
/*
* interrupt service routine
*/
static irqreturn_t pcan_isr(int irq, void *dev_id)
{
struct pcan_pccard *card = dev_id;
int irq_handled;
/* prevent from infinite loop */
for (irq_handled = 0; irq_handled < PCC_ISR_MAX_LOOP; irq_handled++) {
/* handle shared interrupt and next loop */
int nothing_to_handle = 1;
int i;
/* check interrupt for each channel */
for (i = 0; i < card->chan_count; i++) {
struct net_device *netdev;
/*
* check whether the card is present before calling
* sja1000_interrupt() to speed up hotplug detection
*/
if (!pcan_pccard_present(card)) {
/* card unplugged during isr */
return IRQ_NONE;
}
/*
* should check whether all or SJA1000_MAX_IRQ
* interrupts have been handled: loop again to be sure.
*/
netdev = card->channel[i].netdev;
if (netdev &&
sja1000_interrupt(irq, netdev) == IRQ_HANDLED)
nothing_to_handle = 0;
}
if (nothing_to_handle)
break;
}
return (irq_handled) ? IRQ_HANDLED : IRQ_NONE;
}
/*
* free all resources used by the channels and switch off leds and can power
*/
static void pcan_free_channels(struct pcan_pccard *card)
{
int i;
u8 led_mask = 0;
for (i = 0; i < card->chan_count; i++) {
struct net_device *netdev;
char name[IFNAMSIZ];
led_mask |= PCC_LED(i);
netdev = card->channel[i].netdev;
if (!netdev)
continue;
strncpy(name, netdev->name, IFNAMSIZ);
unregister_sja1000dev(netdev);
free_sja1000dev(netdev);
dev_info(&card->pdev->dev, "%s removed\n", name);
}
/* do it only if device not removed */
if (pcan_pccard_present(card)) {
pcan_set_leds(card, led_mask, PCC_LED_OFF);
pcan_set_can_power(card, 0);
}
}
/*
* check if a CAN controller is present at the specified location
*/
static inline int pcan_channel_present(struct sja1000_priv *priv)
{
/* make sure SJA1000 is in reset mode */
pcan_write_canreg(priv, SJA1000_MOD, 1);
pcan_write_canreg(priv, SJA1000_CDR, CDR_PELICAN);
/* read reset-values */
if (pcan_read_canreg(priv, SJA1000_CDR) == CDR_PELICAN)
return 1;
return 0;
}
static int pcan_add_channels(struct pcan_pccard *card)
{
struct pcmcia_device *pdev = card->pdev;
int i, err = 0;
u8 ccr = PCC_CCR_INIT;
/* init common registers (reset channels and leds off) */
card->ccr = ~ccr;
pcan_write_reg(card, PCC_CCR, ccr);
/* wait 2ms before unresetting channels */
usleep_range(2000, 3000);
ccr &= ~PCC_CCR_RST_ALL;
pcan_write_reg(card, PCC_CCR, ccr);
/* create one network device per channel detected */
for (i = 0; i < ARRAY_SIZE(card->channel); i++) {
struct net_device *netdev;
struct sja1000_priv *priv;
netdev = alloc_sja1000dev(0);
if (!netdev) {
err = -ENOMEM;
break;
}
/* update linkages */
priv = netdev_priv(netdev);
priv->priv = card;
SET_NETDEV_DEV(netdev, &pdev->dev);
netdev->dev_id = i;
priv->irq_flags = IRQF_SHARED;
netdev->irq = pdev->irq;
priv->reg_base = card->ioport_addr + PCC_CHAN_OFF(i);
/* check if channel is present */
if (!pcan_channel_present(priv)) {
dev_err(&pdev->dev, "channel %d not present\n", i);
free_sja1000dev(netdev);
continue;
}
priv->read_reg = pcan_read_canreg;
priv->write_reg = pcan_write_canreg;
priv->can.clock.freq = PCC_CAN_CLOCK;
priv->ocr = PCC_OCR;
priv->cdr = PCC_CDR;
/* Neither a slave device distributes the clock */
if (i > 0)
priv->cdr |= CDR_CLK_OFF;
priv->flags |= SJA1000_CUSTOM_IRQ_HANDLER;
/* register SJA1000 device */
err = register_sja1000dev(netdev);
if (err) {
free_sja1000dev(netdev);
continue;
}
card->channel[i].netdev = netdev;
card->chan_count++;
/* set corresponding led on in the new ccr */
ccr &= ~PCC_CCR_LED_OFF_CHAN(i);
dev_info(&pdev->dev,
"%s on channel %d at 0x%p irq %d\n",
netdev->name, i, priv->reg_base, pdev->irq);
}
/* write new ccr (change leds state) */
pcan_write_reg(card, PCC_CCR, ccr);
return err;
}
static int pcan_conf_check(struct pcmcia_device *pdev, void *priv_data)
{
pdev->resource[0]->flags &= ~IO_DATA_PATH_WIDTH;
pdev->resource[0]->flags |= IO_DATA_PATH_WIDTH_8; /* only */
pdev->io_lines = 10;
/* This reserves IO space but doesn't actually enable it */
return pcmcia_request_io(pdev);
}
/*
* free all resources used by the device
*/
static void pcan_free(struct pcmcia_device *pdev)
{
struct pcan_pccard *card = pdev->priv;
if (!card)
return;
free_irq(pdev->irq, card);
pcan_stop_led_timer(card);
pcan_free_channels(card);
ioport_unmap(card->ioport_addr);
kfree(card);
pdev->priv = NULL;
}
/*
* setup PCMCIA socket and probe for PEAK-System PC-CARD
*/
static int pcan_probe(struct pcmcia_device *pdev)
{
struct pcan_pccard *card;
int err;
pdev->config_flags |= CONF_ENABLE_IRQ | CONF_AUTO_SET_IO;
err = pcmcia_loop_config(pdev, pcan_conf_check, NULL);
if (err) {
dev_err(&pdev->dev, "pcmcia_loop_config() error %d\n", err);
goto probe_err_1;
}
if (!pdev->irq) {
dev_err(&pdev->dev, "no irq assigned\n");
err = -ENODEV;
goto probe_err_1;
}
err = pcmcia_enable_device(pdev);
if (err) {
dev_err(&pdev->dev, "pcmcia_enable_device failed err=%d\n",
err);
goto probe_err_1;
}
card = kzalloc(sizeof(struct pcan_pccard), GFP_KERNEL);
if (!card) {
err = -ENOMEM;
goto probe_err_2;
}
card->pdev = pdev;
pdev->priv = card;
/* sja1000 api uses iomem */
card->ioport_addr = ioport_map(pdev->resource[0]->start,
resource_size(pdev->resource[0]));
if (!card->ioport_addr) {
dev_err(&pdev->dev, "couldn't map io port into io memory\n");
err = -ENOMEM;
goto probe_err_3;
}
card->fw_major = pcan_read_reg(card, PCC_FW_MAJOR);
card->fw_minor = pcan_read_reg(card, PCC_FW_MINOR);
/* display board name and firware version */
dev_info(&pdev->dev, "PEAK-System pcmcia card %s fw %d.%d\n",
pdev->prod_id[1] ? pdev->prod_id[1] : "PCAN-PC Card",
card->fw_major, card->fw_minor);
/* detect available channels */
pcan_add_channels(card);
if (!card->chan_count) {
err = -ENOMEM;
goto probe_err_4;
}
/* init the timer which controls the leds */
timer_setup(&card->led_timer, pcan_led_timer, 0);
/* request the given irq */
err = request_irq(pdev->irq, &pcan_isr, IRQF_SHARED, PCC_NAME, card);
if (err) {
dev_err(&pdev->dev, "couldn't request irq%d\n", pdev->irq);
goto probe_err_5;
}
/* power on the connectors */
pcan_set_can_power(card, 1);
return 0;
probe_err_5:
/* unregister can devices from network */
pcan_free_channels(card);
probe_err_4:
ioport_unmap(card->ioport_addr);
probe_err_3:
kfree(card);
pdev->priv = NULL;
probe_err_2:
pcmcia_disable_device(pdev);
probe_err_1:
return err;
}
/*
* release claimed resources
*/
static void pcan_remove(struct pcmcia_device *pdev)
{
pcan_free(pdev);
pcmcia_disable_device(pdev);
}
static struct pcmcia_driver pcan_driver = {
.name = PCC_NAME,
.probe = pcan_probe,
.remove = pcan_remove,
.id_table = pcan_table,
};
module_pcmcia_driver(pcan_driver);
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