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Subject[PATCH 2/3] fsi/master-gpio: Add locking around gpio operations during break & link enable
Date
Currently, we perform GPIO accesses in fsi_master_gpio_break and
fsi_master_link_enable, without holding cmd_lock. This change adds the
appropriate locking.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Christopher Bostic <clbostic@linux.vnet.ibm.com>
---
drivers/fsi/fsi-master-gpio.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/fsi/fsi-master-gpio.c b/drivers/fsi/fsi-master-gpio.c
index ae26187..a6d602e 100644
--- a/drivers/fsi/fsi-master-gpio.c
+++ b/drivers/fsi/fsi-master-gpio.c
@@ -461,12 +461,14 @@ static int fsi_master_gpio_term(struct fsi_master *_master,
static int fsi_master_gpio_break(struct fsi_master *_master, int link)
{
struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
+ unsigned long flags;

if (link != 0)
return -ENODEV;

trace_fsi_master_gpio_break(master);

+ spin_lock_irqsave(&master->cmd_lock, flags);
set_sda_output(master, 1);
sda_out(master, 1);
clock_toggle(master, FSI_PRE_BREAK_CLOCKS);
@@ -475,6 +477,7 @@ static int fsi_master_gpio_break(struct fsi_master *_master, int link)
echo_delay(master);
sda_out(master, 1);
clock_toggle(master, FSI_POST_BREAK_CLOCKS);
+ spin_unlock_irqrestore(&master->cmd_lock, flags);

/* Wait for logic reset to take effect */
udelay(200);
@@ -497,10 +500,14 @@ static void fsi_master_gpio_init(struct fsi_master_gpio *master)
static int fsi_master_gpio_link_enable(struct fsi_master *_master, int link)
{
struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
+ unsigned long flags;

if (link != 0)
return -ENODEV;
+
+ spin_lock_irqsave(&master->cmd_lock, flags);
gpiod_set_value(master->gpio_enable, 1);
+ spin_unlock_irqrestore(&master->cmd_lock, flags);

return 0;
}
--
2.7.4
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