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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: Wolfgang Zarre <lkdev@essax.com>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Wolfgang Zarre 2012-01-15 13:21:34 +01:00 committed by Marc Kleine-Budde
parent 7bb4db93ae
commit 2d5091e08c
1 changed files with 15 additions and 1 deletions
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16
drivers/net/can/cc770/cc770_isa.c
View File

@ -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)