Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752739AbcDKHxV (ORCPT ); Mon, 11 Apr 2016 03:53:21 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:38269 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752303AbcDKHxS (ORCPT ); Mon, 11 Apr 2016 03:53:18 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 11 Apr 2016 13:23:14 +0530 From: gpramod@codeaurora.org To: Stanimir Varbanov Cc: Rob Herring , Mark Rutland , Vinod Koul , Andy Gross , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, dmaengine@vger.kernel.org, Sinan Kaya Subject: Re: [PATCH v2 3/5] dmaengine: qcom: bam_dma: add controlled remotely dt property In-Reply-To: <1459896982-30171-4-git-send-email-stanimir.varbanov@linaro.org> References: <1459896982-30171-1-git-send-email-stanimir.varbanov@linaro.org> <1459896982-30171-4-git-send-email-stanimir.varbanov@linaro.org> Message-ID: User-Agent: Roundcube Webmail/1.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2516 Lines: 69 On 2016-04-06 04:26, Stanimir Varbanov wrote: > Some of the peripherals has bam which is controlled by remote > processor, thus the bam dma driver must avoid register writes > which initialise bam hw block. Those registers are protected > from xPU block and any writes to them will lead to secure > violation and system reboot. > > Adding the contolled_remotely flag in bam driver to avoid > not permitted register writes in bam_init function. > > Signed-off-by: Stanimir Varbanov > Reviewed-by: Andy Gross > --- > Documentation/devicetree/bindings/dma/qcom_bam_dma.txt | 2 ++ > drivers/dma/qcom/bam_dma.c | 7 +++++++ > 2 files changed, 9 insertions(+) > Tested-by: Pramod Gurav > diff --git a/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt > b/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt > index 1c9d48ea4914..9cbf5d9df8fd 100644 > --- a/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt > +++ b/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt > @@ -13,6 +13,8 @@ Required properties: > - clock-names: must contain "bam_clk" entry > - qcom,ee : indicates the active Execution Environment identifier > (0-7) used in > the secure world. > +- qcom,controlled-remotely : optional, indicates that the bam is > controlled by > + remote proccessor i.e. execution environment. > > Example: > > diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c > index 789d5f836bf7..d0f878a78fae 100644 > --- a/drivers/dma/qcom/bam_dma.c > +++ b/drivers/dma/qcom/bam_dma.c > @@ -387,6 +387,7 @@ struct bam_device { > > /* execution environment ID, from DT */ > u32 ee; > + bool controlled_remotely; > > const struct reg_offset_data *layout; > > @@ -1042,6 +1043,9 @@ static int bam_init(struct bam_device *bdev) > val = readl_relaxed(bam_addr(bdev, 0, BAM_NUM_PIPES)); > bdev->num_channels = val & BAM_NUM_PIPES_MASK; > > + if (bdev->controlled_remotely) > + return 0; > + > /* s/w reset bam */ > /* after reset all pipes are disabled and idle */ > val = readl_relaxed(bam_addr(bdev, 0, BAM_CTRL)); > @@ -1129,6 +1133,9 @@ static int bam_dma_probe(struct platform_device > *pdev) > return ret; > } > > + bdev->controlled_remotely = of_property_read_bool(pdev->dev.of_node, > + "qcom,controlled-remotely"); > + > bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk"); > if (IS_ERR(bdev->bamclk)) > return PTR_ERR(bdev->bamclk);