Messages in this thread | | | Date | Fri, 28 Aug 2020 17:16:08 +0530 | From | rojay@codeauro ... | Subject | Re: [PATCH V2 2/2] i2c: i2c-qcom-geni: Add shutdown callback for i2c |
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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@codeaurora.org> >> --- > > 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;
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