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Commit 2d5091e0 authored by Wolfgang Zarre's avatar Wolfgang Zarre Committed by Marc Kleine-Budde
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can: cc770: Fix indirect access deadlock on ISA cards 



This fix avoids a deadlock if an interrupt occurs
during consecutive port operations on ISA cards
utilising indirect access via address and data
port.

Tested on a B&R ISA card.

Cc: linux-can@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: default avatarWolfgang Zarre <lkdev@essax.com>
Acked-by: default avatarWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 7bb4db93

drivers/net/can/cc770/cc770_isa.c

+15 −1
Original line number Diff line number Diff line
@@ -110,6 +110,11 @@ MODULE_PARM_DESC(bcr, "Bus configuration register (default=0x40 [CBY])"); 
#define CC770_IOSIZE          0x20

#define CC770_IOSIZE_INDIRECT 0x02



/* Spinlock for cc770_isa_port_write_reg_indirect

 * and cc770_isa_port_read_reg_indirect

 */

static DEFINE_SPINLOCK(cc770_isa_port_lock);



static struct platform_device *cc770_isa_devs[MAXDEV];



static u8 cc770_isa_mem_read_reg(const struct cc770_priv *priv, int reg)
@@ -138,18 +143,27 @@ static u8 cc770_isa_port_read_reg_indirect(const struct cc770_priv *priv, 
					     int reg)

{

	unsigned long base = (unsigned long)priv->reg_base;

	unsigned long flags;

	u8 val;



	spin_lock_irqsave(&cc770_isa_port_lock, flags);

	outb(reg, base);

	return inb(base + 1);

	val = inb(base + 1);

	spin_unlock_irqrestore(&cc770_isa_port_lock, flags);



	return val;

}



static void cc770_isa_port_write_reg_indirect(const struct cc770_priv *priv,

						int reg, u8 val)

{

	unsigned long base = (unsigned long)priv->reg_base;

	unsigned long flags;



	spin_lock_irqsave(&cc770_isa_port_lock, flags);

	outb(reg, base);

	outb(val, base + 1);

	spin_unlock_irqrestore(&cc770_isa_port_lock, flags);

}



static int __devinit cc770_isa_probe(struct platform_device *pdev)