| Message ID | 20200820103522.26242-3-rojay@codeaurora.org |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
On 2020-08-26 17:26, Akash Asthana wrote: > Hi Roja, > > On 8/20/2020 4:05 PM, Roja Rani Yarubandi wrote: >> 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> >> --- >> 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); >> + } > should be 'else if', because TX and RX can't happen parallel. >> + 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); > > Wrt to current issue context it may be suffice to stop just DMA mode > transfers but why not stop all mode of active transfer during shutdown > in a generic way. > > Regards, > > Akash > Okay, I will include FIFO transfer case also in stop_xfer >> + if (dma) >> + geni_i2c_stop_xfer(gi2c); >> + >> + pm_runtime_put_sync_suspend(gi2c->se.dev); >> +} >> + >> static int __maybe_unused geni_i2c_runtime_suspend(struct device >> *dev) >> { >> int ret; >> @@ -677,6 +719,7 @@ 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, >> diff --git a/include/linux/qcom-geni-se.h >> b/include/linux/qcom-geni-se.h >> index dd464943f717..c3c016496d98 100644 >> --- a/include/linux/qcom-geni-se.h >> +++ b/include/linux/qcom-geni-se.h >> @@ -77,6 +77,7 @@ struct geni_se { >> #define SE_DMA_RX_FSM_RST 0xd58 >> #define SE_HW_PARAM_0 0xe24 >> #define SE_HW_PARAM_1 0xe28 >> +#define SE_DMA_DEBUG_REG0 0xe40 >> /* GENI_FORCE_DEFAULT_REG fields */ >> #define FORCE_DEFAULT BIT(0) >> @@ -207,6 +208,10 @@ struct geni_se { >> #define RX_GENI_CANCEL_IRQ BIT(11) >> #define RX_GENI_GP_IRQ_EXT GENMASK(13, 12) >> +/* SE_DMA_DEBUG_REG0 Register fields */ >> +#define DMA_TX_ACTIVE BIT(0) >> +#define DMA_RX_ACTIVE BIT(1) >> + >> /* SE_HW_PARAM_0 fields */ >> #define TX_FIFO_WIDTH_MSK GENMASK(29, 24) >> #define TX_FIFO_WIDTH_SHFT 24
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); + + pm_runtime_put_sync_suspend(gi2c->se.dev); +} + static int __maybe_unused geni_i2c_runtime_suspend(struct device *dev) { int ret; @@ -677,6 +719,7 @@ 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, diff --git a/include/linux/qcom-geni-se.h b/include/linux/qcom-geni-se.h index dd464943f717..c3c016496d98 100644 --- a/include/linux/qcom-geni-se.h +++ b/include/linux/qcom-geni-se.h @@ -77,6 +77,7 @@ struct geni_se { #define SE_DMA_RX_FSM_RST 0xd58 #define SE_HW_PARAM_0 0xe24 #define SE_HW_PARAM_1 0xe28 +#define SE_DMA_DEBUG_REG0 0xe40 /* GENI_FORCE_DEFAULT_REG fields */ #define FORCE_DEFAULT BIT(0) @@ -207,6 +208,10 @@ struct geni_se { #define RX_GENI_CANCEL_IRQ BIT(11) #define RX_GENI_GP_IRQ_EXT GENMASK(13, 12) +/* SE_DMA_DEBUG_REG0 Register fields */ +#define DMA_TX_ACTIVE BIT(0) +#define DMA_RX_ACTIVE BIT(1) + /* SE_HW_PARAM_0 fields */ #define TX_FIFO_WIDTH_MSK GENMASK(29, 24) #define TX_FIFO_WIDTH_SHFT 24
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> --- 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(+)