If the hardware is still accessing memory after SMMU translation
is disabled (as part of smmu shutdown callback), then the
IOVAs (I/O virtual address) which it was using will go on the bus
as the physical addresses which will result in unknown crashes
like NoC/interconnect errors.
So, implement shutdown callback for i2c driver to suspend the bus
during system "reboot" or "shutdown".
Fixes: 37692de5d523 ("i2c: i2c-qcom-geni: Add bus driver for the Qualcomm GENI I2C controller")
Signed-off-by: Roja Rani Yarubandi <rojay@xxxxxxxxxxxxxx>
---
Changes in V2:
- As per Stephen's comments added seperate function for stop transfer,
fixed minor nitpicks.
- As per Stephen's comments, changed commit text.
Changes in V3:
- As per Stephen's comments, squashed patch 1 into patch 2, added Fixes tag.
- As per Akash's comments, included FIFO case in stop_xfer, fixed minor nitpicks.
Changes in V4:
- As per Stephen's comments cleaned up geni_i2c_stop_xfer function,
added dma_buf in geni_i2c_dev struct to call i2c_put_dma_safe_msg_buf()
from other functions, removed "iova" check in geni_se_rx_dma_unprep()
and geni_se_tx_dma_unprep() functions.
- Added two helper functions geni_i2c_rx_one_msg_done() and
geni_i2c_tx_one_msg_done() to unwrap the things after rx/tx FIFO/DMA
transfers, so that the same can be used in geni_i2c_stop_xfer() function
during shutdown callback. Updated commit text accordingly.
- Checking whether it is tx/rx transfer using I2C_M_RD which is valid for both
FIFO and DMA cases, so dropped DMA_RX_ACTIVE and DMA_TX_ACTIVE bit checking
Changes in V5:
- As per Stephen's comments, added spin_lock_irqsave & spin_unlock_irqsave in
geni_i2c_stop_xfer() function.
Changes in V6:
- As per Stephen's comments, taken care of unsafe lock order in
geni_i2c_stop_xfer().
- Moved spin_lock/unlock to geni_i2c_rx_msg_cleanup() and
geni_i2c_tx_msg_cleanup() functions.
Changes in V7:
- No changes
Changes in V8:
- As per Wolfram Sang comment, removed goto and modified geni_i2c_stop_xfer()
accordingly.
Changes in V9:
- Fixed possbile race by protecting gi2c->cur and calling geni_i2c_abort_xfer()
with adding another parameter to differentiate from which sequence is the
geni_i2c_abort_xfer() called and handle the spin_lock/spin_unlock accordingly
inside geni_i2c_abort_xfer(). For this added two macros ABORT_XFER and
STOP_AND_ABORT_XFER.
- Added a bool variable "stop_xfer" in geni_i2c_dev struct, used to put stop
to upcoming geni_i2c_rx_one_msg() and geni_i2c_tx_one_msg() calls once we
recieve the shutdown call.
- Added gi2c->cur == NULL check in geni_i2c_irq() to not to process the irq
even if any transfer is queued and shutdown to HW received.
Changes in V10:
- As per Stephen's comments, removed ongoing transfers flush and only
suspending i2c bus in shutdown callback.
- Also removed all other changes which have been made for ongoing transfers
flush, handling race issues etc., during shutdown callback.
- Updated commit text accordingly.
Changes in V11:
- As per Stephen's comments, suspended bus in shutdown call using
i2c_mark_adapter_suspended() call to block any future transfers.
drivers/i2c/busses/i2c-qcom-geni.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
index 214b4c913a13..c3ae66ba6345 100644
--- a/drivers/i2c/busses/i2c-qcom-geni.c
+++ b/drivers/i2c/busses/i2c-qcom-geni.c
@@ -650,6 +650,14 @@ static int geni_i2c_remove(struct platform_device *pdev)
return 0;
}
+static void geni_i2c_shutdown(struct platform_device *pdev)
+{
+ struct geni_i2c_dev *gi2c = platform_get_drvdata(pdev);
+
+ /* Make client i2c transfers start failing */
+ i2c_mark_adapter_suspended(&gi2c->adap);
+}
+
static int __maybe_unused geni_i2c_runtime_suspend(struct device *dev)
{
int ret;
@@ -714,6 +722,7 @@ MODULE_DEVICE_TABLE(of, geni_i2c_dt_match);
static struct platform_driver geni_i2c_driver = {
.probe = geni_i2c_probe,
.remove = geni_i2c_remove,
+ .shutdown = geni_i2c_shutdown,
.driver = {
.name = "geni_i2c",
.pm = &geni_i2c_pm_ops,
--
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of Code Aurora Forum, hosted by The Linux Foundation
