On 2020-08-21 05:52, Stephen Boyd wrote:
Quoting Roja Rani Yarubandi (2020-08-20 03:35:22)
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 to i2c driver to unmap DMA mappings
during system "reboot" or "shutdown".
Signed-off-by: Roja Rani Yarubandi <rojay@xxxxxxxxxxxxxx>
---
I'd still put a Fixes tag because it's fixing the driver when someone
runs shutdown.
Okay, will add fixes tag.
Changes in V2:
- As per Stephen's comments added seperate function for stop
transfer,
fixed minor nitpicks.
drivers/i2c/busses/i2c-qcom-geni.c | 43
++++++++++++++++++++++++++++++
include/linux/qcom-geni-se.h | 5 ++++
2 files changed, 48 insertions(+)
diff --git a/drivers/i2c/busses/i2c-qcom-geni.c
b/drivers/i2c/busses/i2c-qcom-geni.c
index 1fda5c7c2cfc..d07f2f33bb75 100644
--- a/drivers/i2c/busses/i2c-qcom-geni.c
+++ b/drivers/i2c/busses/i2c-qcom-geni.c
@@ -486,6 +486,28 @@ static int geni_i2c_xfer(struct i2c_adapter
*adap,
return ret;
}
+static void geni_i2c_stop_xfer(struct geni_i2c_dev *gi2c)
+{
+ u32 val;
+ struct geni_se *se = &gi2c->se;
+
+ val = readl_relaxed(gi2c->se.base + SE_DMA_DEBUG_REG0);
+ if (val & DMA_TX_ACTIVE) {
+ geni_i2c_abort_xfer(gi2c);
+ gi2c->cur_wr = 0;
+ if (gi2c->err)
+ geni_i2c_tx_fsm_rst(gi2c);
+ geni_se_tx_dma_unprep(se, gi2c->tx_dma,
gi2c->xfer_len);
+ }
+ if (val & DMA_RX_ACTIVE) {
+ geni_i2c_abort_xfer(gi2c);
+ gi2c->cur_rd = 0;
+ if (gi2c->err)
+ geni_i2c_rx_fsm_rst(gi2c);
+ geni_se_rx_dma_unprep(se, gi2c->rx_dma,
gi2c->xfer_len);
+ }
+}
+
static u32 geni_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL &
~I2C_FUNC_SMBUS_QUICK);
@@ -617,6 +639,26 @@ static int geni_i2c_remove(struct platform_device
*pdev)
return 0;
}
+static void geni_i2c_shutdown(struct platform_device *pdev)
+{
+ int ret;
+ u32 dma;
+ struct geni_i2c_dev *gi2c = platform_get_drvdata(pdev);
+ struct geni_se *se = &gi2c->se;
+
+ ret = pm_runtime_get_sync(gi2c->se.dev);
+ if (ret < 0) {
+ dev_err(gi2c->se.dev, "Failed to resume device: %d\n",
ret);
+ return;
+ }
+
+ dma = readl_relaxed(se->base + SE_GENI_DMA_MODE_EN);
+ if (dma)
+ geni_i2c_stop_xfer(gi2c);
Any reason the if (dma) check isn't inside geni_i2c_stop_xfer()?
Checking for dma and then bailing out early should work and keep the
logic in one function. Then the pm_runtime_sync() call could go in
there
too and if (!dma) goto out. This assumes that we're going to call
geni_i2c_stop_xfer() from somewhere else, like if a transfer times out
or something?
Okay, will do the changes.
+
+ pm_runtime_put_sync_suspend(gi2c->se.dev);
+}
+
static int __maybe_unused geni_i2c_runtime_suspend(struct device
*dev)
{
int ret;
