| Message ID | 20240819205125.92358-1-vasilykh@arista.com |
|---|---|
| State | New |
| Headers | show |
| Series | i2c: ismt: kill transaction in hardware on timeout | expand |
Hi Vasily, On Mon, Aug 19, 2024 at 01:51:04PM GMT, Vasily Khoruzhick wrote: > On Intel Denverton SoC ismt controller may enter weird state when > transaction gets stuck. It times out in the driver, but unless > transaction is explicitly killed in the controller, it won't be able to > perform new transactions anymore. > > The issue is extremely difficult to reproduce and may take weeks of non- > stop smbus traffic. > > Numerous hours with logic analyzer didn't yield any useful results, it > looks like the controller stops toggling SCK line, i.e. the issue is > likely in the controller, since device doesn't do clock stretching, so > nothing is driving SCK except the host. > > Explicitly kill transaction on timeout to recover the controller from > this state. > > Signed-off-by: Vasily Khoruzhick <vasilykh@arista.com> merged to i2c/i2c-host. Thanks, Andi
diff --git a/drivers/i2c/busses/i2c-ismt.c b/drivers/i2c/busses/i2c-ismt.c index 655b5d851c48..c93c02aa6ac8 100644 --- a/drivers/i2c/busses/i2c-ismt.c +++ b/drivers/i2c/busses/i2c-ismt.c @@ -381,6 +381,15 @@ static int ismt_process_desc(const struct ismt_desc *desc, return -EIO; } +/** + * ismt_kill_transaction() - kill current transaction + * @priv: iSMT private data + */ +static void ismt_kill_transaction(struct ismt_priv *priv) +{ + writel(ISMT_GCTRL_KILL, priv->smba + ISMT_GR_GCTRL); +} + /** * ismt_access() - process an SMBus command * @adap: the i2c host adapter @@ -623,6 +632,7 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr, dma_unmap_single(dev, dma_addr, dma_size, dma_direction); if (unlikely(!time_left)) { + ismt_kill_transaction(priv); ret = -ETIMEDOUT; goto out; }
On Intel Denverton SoC ismt controller may enter weird state when transaction gets stuck. It times out in the driver, but unless transaction is explicitly killed in the controller, it won't be able to perform new transactions anymore. The issue is extremely difficult to reproduce and may take weeks of non- stop smbus traffic. Numerous hours with logic analyzer didn't yield any useful results, it looks like the controller stops toggling SCK line, i.e. the issue is likely in the controller, since device doesn't do clock stretching, so nothing is driving SCK except the host. Explicitly kill transaction on timeout to recover the controller from this state. Signed-off-by: Vasily Khoruzhick <vasilykh@arista.com> --- drivers/i2c/busses/i2c-ismt.c | 10 ++++++++++ 1 file changed, 10 insertions(+)