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Commit a9edcded authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
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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 3e66d013 ("can: populate netdev::dev_id for udev
discrimination").

Reported-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 78c181bc

drivers/net/can/sja1000/sja1000_isa.c

+13 −3
Original line number Diff line number Diff line
@@ -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) {