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can: sja1000_isa: add locking for indirect register access mode 

When accessing the SJA1000 controller registers in the indirect access mode,
writing the register number and reading/writing the data has to be an atomic
attempt.

As the sja1000_isa driver is an old style driver with a fixed number of
instances the locking variable depends on the same index like all the other
configuration elements given on the module command line.

As a positive side effect dev->dev_id is populated by the instance index,
which was missing in 3e66d0138c ("can: populate netdev::dev_id for udev
discrimination").

Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Oliver Hartkopp 2014-04-15 19:30:00 +02:00 committed by Marc Kleine-Budde
parent 78c181bc8a
commit a9edcdedbd
1 changed files with 13 additions and 3 deletions
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16
drivers/net/can/sja1000/sja1000_isa.c
View File

@ -46,6 +46,7 @@ static int clk[MAXDEV];
static unsigned char cdr[MAXDEV] = {[0 ... (MAXDEV - 1)] = 0xff};
static unsigned char ocr[MAXDEV] = {[0 ... (MAXDEV - 1)] = 0xff};
static int indirect[MAXDEV] = {[0 ... (MAXDEV - 1)] = -1};
static spinlock_t indirect_lock[MAXDEV]; /* lock for indirect access mode */
module_param_array(port, ulong, NULL, S_IRUGO);
MODULE_PARM_DESC(port, "I/O port number");
@ -101,19 +102,26 @@ static void sja1000_isa_port_write_reg(const struct sja1000_priv *priv,
static u8 sja1000_isa_port_read_reg_indirect(const struct sja1000_priv *priv,
int reg)
{
unsigned long base = (unsigned long)priv->reg_base;
unsigned long flags, base = (unsigned long)priv->reg_base;
u8 readval;
spin_lock_irqsave(&indirect_lock[priv->dev->dev_id], flags);
outb(reg, base);
return inb(base + 1);
readval = inb(base + 1);
spin_unlock_irqrestore(&indirect_lock[priv->dev->dev_id], flags);
return readval;
}
static void sja1000_isa_port_write_reg_indirect(const struct sja1000_priv *priv,
int reg, u8 val)
{
unsigned long base = (unsigned long)priv->reg_base;
unsigned long flags, base = (unsigned long)priv->reg_base;
spin_lock_irqsave(&indirect_lock[priv->dev->dev_id], flags);
outb(reg, base);
outb(val, base + 1);
spin_unlock_irqrestore(&indirect_lock[priv->dev->dev_id], flags);
}
static int sja1000_isa_probe(struct platform_device *pdev)
@ -169,6 +177,7 @@ static int sja1000_isa_probe(struct platform_device *pdev)
if (iosize == SJA1000_IOSIZE_INDIRECT) {
priv->read_reg = sja1000_isa_port_read_reg_indirect;
priv->write_reg = sja1000_isa_port_write_reg_indirect;
spin_lock_init(&indirect_lock[idx]);
} else {
priv->read_reg = sja1000_isa_port_read_reg;
priv->write_reg = sja1000_isa_port_write_reg;
@ -198,6 +207,7 @@ static int sja1000_isa_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, dev);
SET_NETDEV_DEV(dev, &pdev->dev);
dev->dev_id = idx;
err = register_sja1000dev(dev);
if (err) {