lkml.org 
[lkml]   [2011]   [Aug]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] i2c: tegra: Check for overflow errors with BUG_ON.
    Hi,

    On Mon, Aug 15, 2011 at 11:49:32AM -0700, Doug Anderson wrote:
    > This change doesn't fix any known problems but turns
    > on the overflow detection feature of the i2c controller
    > in the hopes of flushing out any current (or future)
    > bugs in the i2c driver.
    >
    > Inspired by a change on nvidia's git server:
    > http://nv-tegra.nvidia.com/gitweb/?p=linux-2.6.git;a=commit;h=266d1b7397284505e55d06254b497cb32be07b69
    >
    > Signed-off-by: Doug Anderson <dianders@chromium.org>
    > ---
    > drivers/i2c/busses/i2c-tegra.c | 11 ++++++++---
    > 1 files changed, 8 insertions(+), 3 deletions(-)
    >
    > diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
    > index 2440b74..4dbba23 100644
    > --- a/drivers/i2c/busses/i2c-tegra.c
    > +++ b/drivers/i2c/busses/i2c-tegra.c
    > @@ -367,7 +367,8 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
    > static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
    > {
    > u32 status;
    > - const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
    > + const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST |
    > + I2C_INT_TX_FIFO_OVERFLOW;
    > struct tegra_i2c_dev *i2c_dev = dev_id;
    >
    > status = i2c_readl(i2c_dev, I2C_INT_STATUS);
    > @@ -389,6 +390,9 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
    > }
    >
    > if (unlikely(status & status_err)) {
    > + /* Don't pass this back--it can only happen due to a bug. */
    > + BUG_ON(status & I2C_INT_TX_FIFO_OVERFLOW);

    so due to a FIFO overflow you lock up the whole system ? Can't you e.g.
    reset the controller and reconfigure it rather than locking up the
    system ?

    --
    balbi
    [unhandled content-type:application/pgp-signature]
    \
     
     \ /
      Last update: 2011-08-15 21:21    [from the cache]
    ©2003-2014 Jasper Spaans. hosted at Digital Ocean