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Wed, 26 Aug 2020 11:56:55 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id BAF53C433CA; Wed, 26 Aug 2020 11:56:54 +0000 (UTC) Received: from [192.168.1.100] (unknown [47.8.163.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: akashast) by smtp.codeaurora.org (Postfix) with ESMTPSA id 1428AC433CB; Wed, 26 Aug 2020 11:56:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 1428AC433CB Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=akashast@codeaurora.org Subject: Re: [PATCH V2 2/2] i2c: i2c-qcom-geni: Add shutdown callback for i2c To: Roja Rani Yarubandi , wsa@kernel.org Cc: swboyd@chromium.org, dianders@chromium.org, saiprakash.ranjan@codeaurora.org, gregkh@linuxfoundation.org, mka@chromium.org, msavaliy@qti.qualcomm.com, skakit@codeaurora.org, rnayak@codeaurora.org, agross@kernel.org, bjorn.andersson@linaro.org, linux-arm-msm@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, sumit.semwal@linaro.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org References: <20200820103522.26242-1-rojay@codeaurora.org> <20200820103522.26242-3-rojay@codeaurora.org> From: Akash Asthana Message-ID: Date: Wed, 26 Aug 2020 17:26:30 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200820103522.26242-3-rojay@codeaurora.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org 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 > --- > 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 > + 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 -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project