From 46b2dfc0aa79277c2ed119975de72f49bddd77c9 Mon Sep 17 00:00:00 2001 From: Vasily Khoruzhick Date: Mon, 19 Aug 2024 13:51:04 -0700 Subject: i2c: ismt: kill transaction in hardware on timeout 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 Signed-off-by: Andi Shyti --- drivers/i2c/busses/i2c-ismt.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'drivers/i2c/busses') 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; } -- cgit v1.2.3