From patchwork Mon Jul 19 14:53:14 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Gerhold X-Patchwork-Id: 12386049 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79BEFC636CE for ; Mon, 19 Jul 2021 15:02:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 66C456113A for ; Mon, 19 Jul 2021 15:02:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241866AbhGSOV7 (ORCPT ); Mon, 19 Jul 2021 10:21:59 -0400 Received: from mo4-p02-ob.smtp.rzone.de ([81.169.146.168]:29110 "EHLO mo4-p02-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242651AbhGSOUS (ORCPT ); Mon, 19 Jul 2021 10:20:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1626706846; s=strato-dkim-0002; d=gerhold.net; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=6MnR6L4mXMePcbKExrBmlzA/geD023b1awg39iUW1gY=; b=V5IXFQ1bkuRIcrEYRjBENZPC8IKTWeaZvEa2luLmj+ad5HrPjXIMoeeNFm8dZECwpz b4PVGmWLkjHMV5QDI/tiRtJsI22seZy8tonlBEWVz3SQMdL1PYx+NV1rKlcv+rPOaoLQ V/8y0XzqA12VAMWdmEMzqQjpWcCIEW47cl7d0YGAOwyL6JDHkSsboEE6fYD1XfLpJhh0 g17xiXXNDxqFmk1jYJ1dDcDBWCqVn5HGXASgbA5+0npzvNKZg2DeN5A9xyscn/VCP0p9 4GZFEpar4Q5v+vMxyjPSUmpVCSG28bjfAl530yPMWhDaTQhPmPWtGhNcM4uXSuMVBeTh L+mw== Authentication-Results: strato.com; dkim=none X-RZG-AUTH: ":P3gBZUipdd93FF5ZZvYFPugejmSTVR2nRPhVORvLd4SsytBXS7IYBkLahKxB4m6O43/v" X-RZG-CLASS-ID: mo00 Received: from droid.. by smtp.strato.de (RZmta 47.28.1 DYNA|AUTH) with ESMTPSA id g02a44x6JF0g42g (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Mon, 19 Jul 2021 17:00:42 +0200 (CEST) From: Stephan Gerhold To: "David S. Miller" , Jakub Kicinski Cc: Loic Poulain , Sergey Ryazanov , Johannes Berg , Bjorn Andersson , Andy Gross , Vinod Koul , Rob Herring , Aleksander Morgado , netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org, dmaengine@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, phone-devel@vger.kernel.org, ~postmarketos/upstreaming@lists.sr.ht, Jeffrey Hugo , Stephan Gerhold Subject: [RFC PATCH net-next 1/4] dt-bindings: dmaengine: bam_dma: Add remote power collapse mode Date: Mon, 19 Jul 2021 16:53:14 +0200 Message-Id: <20210719145317.79692-2-stephan@gerhold.net> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719145317.79692-1-stephan@gerhold.net> References: <20210719145317.79692-1-stephan@gerhold.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC In some configurations, the BAM DMA controller is set up by a remote processor and the local processor can simply start making use of it without setting up the BAM. This is already supported using the "qcom,controlled-remotely" property. However, for some reason another possible configuration is that the remote processor is responsible for powering up the BAM, but we are still responsible for initializing it (e.g. resetting it etc). Add a "qcom,remote-power-collapse" property to describe that configuration. Signed-off-by: Stephan Gerhold --- NOTE: This is *not* a compile-time requirement for the BAM-DMUX driver so this could also go through the dmaengine tree. Also note that there is an ongoing effort to convert these bindings to DT schema but sadly there were not any updates for a while. :/ https://lore.kernel.org/linux-arm-msm/20210519143700.27392-2-bhupesh.sharma@linaro.org/ --- Documentation/devicetree/bindings/dma/qcom_bam_dma.txt | 2 ++ 1 file changed, 2 insertions(+) diff --git a/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt b/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt index cf5b9e44432c..362a4f0905a8 100644 --- a/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt +++ b/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt @@ -15,6 +15,8 @@ Required properties: the secure world. - qcom,controlled-remotely : optional, indicates that the bam is controlled by remote proccessor i.e. execution environment. +- qcom,remote-power-collapse : optional, indicates that the bam is powered up by + a remote processor but must be initialized by the local processor. - num-channels : optional, indicates supported number of DMA channels in a remotely controlled bam. - qcom,num-ees : optional, indicates supported number of Execution Environments From patchwork Mon Jul 19 14:53:15 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Gerhold X-Patchwork-Id: 12386043 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 257B8C6377C for ; Mon, 19 Jul 2021 15:02:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 12F0D61003 for ; Mon, 19 Jul 2021 15:02:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242338AbhGSOVc (ORCPT ); Mon, 19 Jul 2021 10:21:32 -0400 Received: from mo4-p02-ob.smtp.rzone.de ([85.215.255.83]:12383 "EHLO mo4-p02-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239395AbhGSOUY (ORCPT ); Mon, 19 Jul 2021 10:20:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1626706850; s=strato-dkim-0002; d=gerhold.net; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=pubmbmHlyqpaiVv+WMB17cjKMc+dY8K5IuYGYoXn/CE=; b=hIqeiU24ArSSuEFFlyD5sVQuDKtyhYyiED1Ctvq6hfv9LxPAGN1CWm5wpK3kQLwmqE uxfr6IQK5a6w5SsMFLvBxh48ZaZSZ+RUPcYuevwQ/EvCaJhsOoVgxCRQDQdpvy6VgrGf +CKQq25taYdLIiIxv2a8M+JxmUUdF/dk7U93z0/beiISGqesVcbGKM9Y7aJ1EQEw5et4 6A+SFCmiX8S08GQPtMPaCYXOY19b6ZP9w+wYr1lDK66RJoy249mdEEvZKCbOFkBnOBAH tCf+3iHrbKxE4UrsHXSkJqwDq6A2npHZf9jFkhU/YBL+xdqojKDwk+QM/J2dzCAYIMiV ciNg== Authentication-Results: strato.com; dkim=none X-RZG-AUTH: ":P3gBZUipdd93FF5ZZvYFPugejmSTVR2nRPhVORvLd4SsytBXS7IYBkLahKxB4m6O43/v" X-RZG-CLASS-ID: mo00 Received: from droid.. by smtp.strato.de (RZmta 47.28.1 DYNA|AUTH) with ESMTPSA id g02a44x6JF0k432 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Mon, 19 Jul 2021 17:00:46 +0200 (CEST) From: Stephan Gerhold To: "David S. Miller" , Jakub Kicinski Cc: Loic Poulain , Sergey Ryazanov , Johannes Berg , Bjorn Andersson , Andy Gross , Vinod Koul , Rob Herring , Aleksander Morgado , netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org, dmaengine@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, phone-devel@vger.kernel.org, ~postmarketos/upstreaming@lists.sr.ht, Jeffrey Hugo , Stephan Gerhold Subject: [RFC PATCH net-next 2/4] dmaengine: qcom: bam_dma: Add remote power collapse mode Date: Mon, 19 Jul 2021 16:53:15 +0200 Message-Id: <20210719145317.79692-3-stephan@gerhold.net> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719145317.79692-1-stephan@gerhold.net> References: <20210719145317.79692-1-stephan@gerhold.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC In some configurations, the BAM DMA controller is set up by a remote processor and the local processor can simply start making use of it without setting up the BAM. This is already supported using the "qcom,controlled-remotely" property. However, for some reason another possible configuration is that the remote processor is responsible for powering up the BAM, but we are still responsible for initializing it (e.g. resetting it etc). This configuration is quite challenging to handle properly because the power control is handled through separate channels (e.g. device-specific SMSM interrupts / smem-states). Great care must be taken to ensure the BAM registers are not accessed while the BAM is power-collapsed since this results in a bus stall. Attempt to support this configuration with minimal device-specific code in the bam_dma driver by tracking the number of requested channels. Consumers of DMA channels are responsible to only request DMA channels when the BAM was powered on by the remote processor, and to release them before the BAM is power-collapsed. When the first channel is requested the BAM is initialized (reset) and it is also put into reset when the last channel was released. Signed-off-by: Stephan Gerhold --- NOTE: This is *not* a compile-time requirement for the BAM-DMUX driver so this could also go through the dmaengine tree. I tried to come up with other solutions for this situation, but this is the cleanest I came up with so far. The main advantage is that it keeps the bam_dma driver generic and fairly simple. The main disadvantage might be that there is some overhead when the DMA channels are repeatedly requested and released (the BAM-DMUX driver uses PM runtime to autosuspend after 1 second of inactivity). Some alternative ideas (but I'm not sure how they would work exactly): - Have some dmaengine_*() operation to make the bam_dma driver aware that the BAM is power-collapsed (instead of requesting/releasing the channels every time). - Give the BAM-DMUX power control IRQ to bam_dma so it knows when the BAM is power-collapsed or not. - Perhaps even give the smem-state to bam_dma so it could request powering on the BAM itself. This would be quite strange though, since bam_dma already uses runtime PM but differently (only active during register writes, not necessarily active during transfers). Note however that the power control of BAM-DMUX also involves queuing RX buffers so there would be much more coordination needed between bam_dma and bam-dmux. All in all, I think the solution in this patch is still the cleanest approach so far. --- drivers/dma/qcom/bam_dma.c | 88 ++++++++++++++++++++++++-------------- 1 file changed, 56 insertions(+), 32 deletions(-) diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c index c8a77b428b52..8bf6c50bda73 100644 --- a/drivers/dma/qcom/bam_dma.c +++ b/drivers/dma/qcom/bam_dma.c @@ -388,6 +388,8 @@ struct bam_device { /* execution environment ID, from DT */ u32 ee; bool controlled_remotely; + bool remote_power_collapse; + u32 active_channels; const struct reg_offset_data *layout; @@ -415,6 +417,44 @@ static inline void __iomem *bam_addr(struct bam_device *bdev, u32 pipe, r.ee_mult * bdev->ee; } +/** + * bam_reset - reset and initialize BAM registers + * @bdev: bam device + */ +static void bam_reset(struct bam_device *bdev) +{ + u32 val; + + /* s/w reset bam */ + /* after reset all pipes are disabled and idle */ + val = readl_relaxed(bam_addr(bdev, 0, BAM_CTRL)); + val |= BAM_SW_RST; + writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL)); + val &= ~BAM_SW_RST; + writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL)); + + /* make sure previous stores are visible before enabling BAM */ + wmb(); + + /* enable bam */ + val |= BAM_EN; + writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL)); + + /* set descriptor threshhold, start with 4 bytes */ + writel_relaxed(DEFAULT_CNT_THRSHLD, + bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD)); + + /* Enable default set of h/w workarounds, ie all except BAM_FULL_PIPE */ + writel_relaxed(BAM_CNFG_BITS_DEFAULT, bam_addr(bdev, 0, BAM_CNFG_BITS)); + + /* enable irqs for errors */ + writel_relaxed(BAM_ERROR_EN | BAM_HRESP_ERR_EN, + bam_addr(bdev, 0, BAM_IRQ_EN)); + + /* unmask global bam interrupt */ + writel_relaxed(BAM_IRQ_MSK, bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE)); +} + /** * bam_reset_channel - Reset individual BAM DMA channel * @bchan: bam channel @@ -512,6 +552,9 @@ static int bam_alloc_chan(struct dma_chan *chan) return -ENOMEM; } + if (bdev->active_channels++ == 0 && bdev->remote_power_collapse) + bam_reset(bdev); + return 0; } @@ -565,6 +608,13 @@ static void bam_free_chan(struct dma_chan *chan) /* disable irq */ writel_relaxed(0, bam_addr(bdev, bchan->id, BAM_P_IRQ_EN)); + if (--bdev->active_channels == 0 && bdev->remote_power_collapse) { + /* s/w reset bam */ + val = readl_relaxed(bam_addr(bdev, 0, BAM_CTRL)); + val |= BAM_SW_RST; + writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL)); + } + err: pm_runtime_mark_last_busy(bdev->dev); pm_runtime_put_autosuspend(bdev->dev); @@ -1164,38 +1214,10 @@ static int bam_init(struct bam_device *bdev) bdev->num_channels = val & BAM_NUM_PIPES_MASK; } - if (bdev->controlled_remotely) + if (bdev->controlled_remotely || bdev->remote_power_collapse) return 0; - /* s/w reset bam */ - /* after reset all pipes are disabled and idle */ - val = readl_relaxed(bam_addr(bdev, 0, BAM_CTRL)); - val |= BAM_SW_RST; - writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL)); - val &= ~BAM_SW_RST; - writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL)); - - /* make sure previous stores are visible before enabling BAM */ - wmb(); - - /* enable bam */ - val |= BAM_EN; - writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL)); - - /* set descriptor threshhold, start with 4 bytes */ - writel_relaxed(DEFAULT_CNT_THRSHLD, - bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD)); - - /* Enable default set of h/w workarounds, ie all except BAM_FULL_PIPE */ - writel_relaxed(BAM_CNFG_BITS_DEFAULT, bam_addr(bdev, 0, BAM_CNFG_BITS)); - - /* enable irqs for errors */ - writel_relaxed(BAM_ERROR_EN | BAM_HRESP_ERR_EN, - bam_addr(bdev, 0, BAM_IRQ_EN)); - - /* unmask global bam interrupt */ - writel_relaxed(BAM_IRQ_MSK, bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE)); - + bam_reset(bdev); return 0; } @@ -1257,8 +1279,10 @@ static int bam_dma_probe(struct platform_device *pdev) bdev->controlled_remotely = of_property_read_bool(pdev->dev.of_node, "qcom,controlled-remotely"); + bdev->remote_power_collapse = of_property_read_bool(pdev->dev.of_node, + "qcom,remote-power-collapse"); - if (bdev->controlled_remotely) { + if (bdev->controlled_remotely || bdev->remote_power_collapse) { ret = of_property_read_u32(pdev->dev.of_node, "num-channels", &bdev->num_channels); if (ret) @@ -1270,7 +1294,7 @@ static int bam_dma_probe(struct platform_device *pdev) dev_err(bdev->dev, "num-ees unspecified in dt\n"); } - if (bdev->controlled_remotely) + if (bdev->controlled_remotely || bdev->remote_power_collapse) bdev->bamclk = devm_clk_get_optional(bdev->dev, "bam_clk"); else bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk"); From patchwork Mon Jul 19 14:53:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Gerhold X-Patchwork-Id: 12386045 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C3F79C07E9B for ; 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dkim=none X-RZG-AUTH: ":P3gBZUipdd93FF5ZZvYFPugejmSTVR2nRPhVORvLd4SsytBXS7IYBkLahKxB4m6O43/v" X-RZG-CLASS-ID: mo00 Received: from droid.. by smtp.strato.de (RZmta 47.28.1 DYNA|AUTH) with ESMTPSA id g02a44x6JF0o43M (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Mon, 19 Jul 2021 17:00:50 +0200 (CEST) From: Stephan Gerhold To: "David S. Miller" , Jakub Kicinski Cc: Loic Poulain , Sergey Ryazanov , Johannes Berg , Bjorn Andersson , Andy Gross , Vinod Koul , Rob Herring , Aleksander Morgado , netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org, dmaengine@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, phone-devel@vger.kernel.org, ~postmarketos/upstreaming@lists.sr.ht, Jeffrey Hugo , Stephan Gerhold Subject: [RFC PATCH net-next 3/4] dt-bindings: net: Add schema for Qualcomm BAM-DMUX Date: Mon, 19 Jul 2021 16:53:16 +0200 Message-Id: <20210719145317.79692-4-stephan@gerhold.net> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719145317.79692-1-stephan@gerhold.net> References: <20210719145317.79692-1-stephan@gerhold.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC The BAM Data Multiplexer provides access to the network data channels of modems integrated into many older Qualcomm SoCs, e.g. Qualcomm MSM8916 or MSM8974. It is built using a simple protocol layer on top of a DMA engine (Qualcomm BAM) and bidirectional interrupts to coordinate power control. The device tree node combines the incoming interrupt with the outgoing interrupts (smem-states) as well as the two DMA channels, which allows the BAM-DMUX driver to request all necessary resources. Signed-off-by: Stephan Gerhold --- .../bindings/net/qcom,bam-dmux.yaml | 87 +++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml diff --git a/Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml b/Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml new file mode 100644 index 000000000000..33e125e70cb4 --- /dev/null +++ b/Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml @@ -0,0 +1,87 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/net/qcom,bam-dmux.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Qualcomm BAM Data Multiplexer + +maintainers: + - Stephan Gerhold + +description: | + The BAM Data Multiplexer provides access to the network data channels + of modems integrated into many older Qualcomm SoCs, e.g. Qualcomm MSM8916 + or MSM8974. It is built using a simple protocol layer on top of a DMA engine + (Qualcomm BAM DMA) and bidirectional interrupts to coordinate power control. + +properties: + compatible: + const: qcom,bam-dmux + + interrupts: + description: + Interrupts used by the modem to signal the AP. + Both interrupts must be declared as IRQ_TYPE_EDGE_BOTH. + items: + - description: Power control + - description: Power control acknowledgment + + interrupt-names: + items: + - const: pc + - const: pc-ack + + qcom,smem-states: + $ref: /schemas/types.yaml#/definitions/phandle-array + description: State bits used by the AP to signal the modem. + items: + - description: Power control + - description: Power control acknowledgment + + qcom,smem-state-names: + description: Names for the state bits used by the AP to signal the modem. + items: + - const: pc + - const: pc-ack + + dmas: + items: + - description: TX DMA channel phandle + - description: RX DMA channel phandle + + dma-names: + items: + - const: tx + - const: rx + +required: + - compatible + - interrupts + - interrupt-names + - qcom,smem-states + - qcom,smem-state-names + - dmas + - dma-names + +additionalProperties: false + +examples: + - | + #include + + mpss: remoteproc { + bam-dmux { + compatible = "qcom,bam-dmux"; + + interrupt-parent = <&modem_smsm>; + interrupts = <1 IRQ_TYPE_EDGE_BOTH>, <11 IRQ_TYPE_EDGE_BOTH>; + interrupt-names = "pc", "pc-ack"; + + qcom,smem-states = <&apps_smsm 1>, <&apps_smsm 11>; + qcom,smem-state-names = "pc", "pc-ack"; + + dmas = <&bam_dmux_dma 4>, <&bam_dmux_dma 5>; + dma-names = "tx", "rx"; + }; + }; From patchwork Mon Jul 19 14:53:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Gerhold X-Patchwork-Id: 12386047 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53236C12002 for ; Mon, 19 Jul 2021 15:02:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3AC22610D2 for ; Mon, 19 Jul 2021 15:02:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243018AbhGSOVg (ORCPT ); Mon, 19 Jul 2021 10:21:36 -0400 Received: from mo4-p03-ob.smtp.rzone.de ([81.169.146.172]:17183 "EHLO mo4-p03-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241856AbhGSOU0 (ORCPT ); Mon, 19 Jul 2021 10:20:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1626706856; s=strato-dkim-0002; d=gerhold.net; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=WGIBHoAGV6sTQaLi15c2O0Vquf84jrDTXGEW6zN3BLU=; b=g6r97+XNBrHy8AdBR14ZzQqLH/5jqONSuqZCcAMI/e8XtF8jRa77HG3GG0Q0Vpgfwb yVQXIJmGXbsiL1YVfsc2sMjhQU5RJWZzjjqos5pZ528cX+FOoDjB2xdPTUiAwXe5F7mc PeHcNyD/JL4afpkRizfu+g7/9JC1HsrixY46VouA6pcq8jWn8wRfrNMqL0fStKnmSaGM 1/jjTNBTzaYe72QEcIKDR9iIR/TixG0KwehMsRy/SHmRivpzDL7Exyh5RhpmTOGZmOqe rxbHXEfkERhbYq8vTbgRpwrevOF/tzJmqezsmJcHd7dBOcDmCV8mTBQAV98XViA5iNMg gwyg== Authentication-Results: strato.com; dkim=none X-RZG-AUTH: ":P3gBZUipdd93FF5ZZvYFPugejmSTVR2nRPhVORvLd4SsytBXS7IYBkLahKxB4m6O43/v" X-RZG-CLASS-ID: mo00 Received: from droid.. by smtp.strato.de (RZmta 47.28.1 DYNA|AUTH) with ESMTPSA id g02a44x6JF0r43g (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Mon, 19 Jul 2021 17:00:53 +0200 (CEST) From: Stephan Gerhold To: "David S. Miller" , Jakub Kicinski Cc: Loic Poulain , Sergey Ryazanov , Johannes Berg , Bjorn Andersson , Andy Gross , Vinod Koul , Rob Herring , Aleksander Morgado , netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org, dmaengine@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, phone-devel@vger.kernel.org, ~postmarketos/upstreaming@lists.sr.ht, Jeffrey Hugo , Stephan Gerhold Subject: [RFC PATCH net-next 4/4] net: wwan: Add Qualcomm BAM-DMUX WWAN network driver Date: Mon, 19 Jul 2021 16:53:17 +0200 Message-Id: <20210719145317.79692-5-stephan@gerhold.net> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719145317.79692-1-stephan@gerhold.net> References: <20210719145317.79692-1-stephan@gerhold.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC The BAM Data Multiplexer provides access to the network data channels of modems integrated into many older Qualcomm SoCs, e.g. Qualcomm MSM8916 or MSM8974. It is built using a simple protocol layer on top of a DMA engine (Qualcomm BAM) and bidirectional interrupts to coordinate power control. The modem announces a fixed set of channels by sending an OPEN command. The driver exports each channel as separate network interface so that a connection can be established via QMI from userspace. The network interface can work either in Ethernet or Raw-IP mode (configurable via QMI). However, Ethernet mode seems to be broken with most firmwares (network packets are actually received as Raw-IP), therefore the driver only supports Raw-IP mode. The driver uses runtime PM to coordinate power control with the modem. TX/RX buffers are put in a kind of "ring queue" and submitted via the bam_dma driver of the DMAEngine subsystem. The basic architecture looks roughly like this: +------------+ +-------+ [IPv4/6] | BAM-DMUX | | | [Data...] | | | | ---------->|rmnet0 | [DMUX chan: x] | | [IPv4/6] | (chan: 0) | [IPv4/6] | | [Data...] | | [Data...] | | ---------->|rmnet1 |--------------->| Modem | | (chan: 1) | BAM | | [IPv4/6] | ... | (DMA Engine) | | [Data...] | | | | ---------->|rmnet7 | | | | (chan: 7) | | | +------------+ +-------+ However, on newer SoCs/firmware versions Qualcomm began gradually moving to QMAP (rmnet driver) as backend-independent protocol for multiplexing and data aggegration. Some firmware versions allow using QMAP on top of BAM-DMUX (effectively resulting in a second multiplexing layer plus data aggregation). The architecture with QMAP would look roughly like this: +-------------+ +------------+ +-------+ [IPv4/6] | RMNET | | BAM-DMUX | | | [Data...] | | | | [DMUX chan: 0] | | ---------->|rmnet_data1 | ----->|rmnet0 | [QMAP mux-id: x] | | | (mux-id: 1) | | | (chan: 0) | [IPv4/6] | | | | | | | [Data...] | | [IPv4/6] | ... |------ | |----------------->| Modem | [Data...] | | | | BAM | | ---------->|rmnet_data42 | [QMAP: x] |[rmnet1] | (DMA Engine) | | | (mux-id: 42)| [IPv4/6] |... unused! | | | | | [Data...] |[rmnet7] | | | | | | | | | +-------------+ +------------+ +-------+ In this case, rmnet1-7 would remain unused. The firmware used on the most recent SoCs with BAM-DMUX even seems to announce only a single BAM-DMUX channel (rmnet0), which makes QMAP the only option for multiplexing there. So far the driver is mainly tested on various smartphones/tablets based on Qualcomm MSM8916/MSM8974 without QMAP. It looks like QMAP depends on a MTU negotiation feature in BAM-DMUX which is not yet supported by the driver. Signed-off-by: Stephan Gerhold --- Note that this is my first network driver, so I apologize in advance if I made some obvious mistakes. :) I'm not sure how to integrate the driver with the WWAN subsystem yet. At the moment the driver creates network interfaces for all channels announced by the modem, it does not make use of the WWAN link management yet. Unfortunately, this is a bit complicated: Both QMAP and the built-in multiplexing layer might be needed at some point. There are firmware versions that do not support QMAP and the other way around (the built-in multiplexing was disabled on very recent firmware versions). Only userspace can check if QMAP is supported in the firmware (via QMI). I could ignore QMAP completely for now but I think someone will show up who will need this eventually. And if there is going to be common code for QMAP/rmnet link management it would be nice if BAM-DMUX could also make use of it. But the question is, how could this look like? How do we know if we should create a link for QMAP or a BAM-DMUX channel? Does it even make sense to manage the 1-8 channels via the WWAN link management? Another problem is that the WWAN subsystem currently creates all network interfaces below the common WWAN device. This means that userspace like ModemManager has no way to check which driver provides them. This is necessary though to decide how to set it up via QMI (ModemManager uses it). For reference, example of the channels announced by firmwares on various SoCs: - Qualcomm MSM8974: channel 0-7, QMAP not supported - Qualcomm MSM8916: channel 0-7, QMAP usually supported, but not always (depends on firmware version) - Qualcomm MSM8937: channel 0 only, QMAP required for multiplexing(?) (Note: This one is theoretic based on logs, this was not tested so far...) --- MAINTAINERS | 8 + drivers/net/wwan/Kconfig | 13 + drivers/net/wwan/Makefile | 1 + drivers/net/wwan/qcom_bam_dmux.c | 907 +++++++++++++++++++++++++++++++ 4 files changed, 929 insertions(+) create mode 100644 drivers/net/wwan/qcom_bam_dmux.c diff --git a/MAINTAINERS b/MAINTAINERS index e09c3944240c..0d7d2fbadfb2 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -15304,6 +15304,14 @@ S: Supported W: https://wireless.wiki.kernel.org/en/users/Drivers/ath9k F: drivers/net/wireless/ath/ath9k/ +QUALCOMM BAM-DMUX WWAN NETWORK DRIVER +M: Stephan Gerhold +L: netdev@vger.kernel.org +L: linux-arm-msm@vger.kernel.org +S: Maintained +F: Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml +F: drivers/net/wwan/bam_dmux.c + QUALCOMM CAMERA SUBSYSTEM DRIVER M: Robert Foss M: Todor Tomov diff --git a/drivers/net/wwan/Kconfig b/drivers/net/wwan/Kconfig index de9384326bc8..efb2b859ab55 100644 --- a/drivers/net/wwan/Kconfig +++ b/drivers/net/wwan/Kconfig @@ -38,6 +38,19 @@ config MHI_WWAN_CTRL To compile this driver as a module, choose M here: the module will be called mhi_wwan_ctrl. +config QCOM_BAM_DMUX + tristate "Qualcomm BAM-DMUX WWAN network driver" + depends on (DMA_ENGINE && PM && QCOM_SMEM_STATE) || COMPILE_TEST + help + The BAM Data Multiplexer provides access to the network data channels + of modems integrated into many older Qualcomm SoCs, e.g. Qualcomm + MSM8916 or MSM8974. The connection can be established via QMI/AT from + userspace with control ports available through the WWAN subsystem + (CONFIG_RPMSG_WWAN_CTRL) or QRTR network sockets (CONFIG_QRTR). + + To compile this driver as a module, choose M here: the module will be + called qcom_bam_dmux. + config RPMSG_WWAN_CTRL tristate "RPMSG WWAN control driver" depends on RPMSG diff --git a/drivers/net/wwan/Makefile b/drivers/net/wwan/Makefile index d90ac33abaef..a804f6d9637e 100644 --- a/drivers/net/wwan/Makefile +++ b/drivers/net/wwan/Makefile @@ -9,5 +9,6 @@ wwan-objs += wwan_core.o obj-$(CONFIG_WWAN_HWSIM) += wwan_hwsim.o obj-$(CONFIG_MHI_WWAN_CTRL) += mhi_wwan_ctrl.o +obj-$(CONFIG_QCOM_BAM_DMUX) += qcom_bam_dmux.o obj-$(CONFIG_RPMSG_WWAN_CTRL) += rpmsg_wwan_ctrl.o obj-$(CONFIG_IOSM) += iosm/ diff --git a/drivers/net/wwan/qcom_bam_dmux.c b/drivers/net/wwan/qcom_bam_dmux.c new file mode 100644 index 000000000000..b1e69f5263ac --- /dev/null +++ b/drivers/net/wwan/qcom_bam_dmux.c @@ -0,0 +1,907 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Qualcomm BAM-DMUX WWAN network driver + * Copyright (c) 2020, Stephan Gerhold + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define BAM_DMUX_BUFFER_SIZE SZ_2K +#define BAM_DMUX_HDR_SIZE sizeof(struct bam_dmux_hdr) +#define BAM_DMUX_MAX_DATA_SIZE (BAM_DMUX_BUFFER_SIZE - BAM_DMUX_HDR_SIZE) +#define BAM_DMUX_NUM_SKB 32 + +#define BAM_DMUX_HDR_MAGIC 0x33fc + +#define BAM_DMUX_AUTOSUSPEND_DELAY 1000 +#define BAM_DMUX_REMOTE_TIMEOUT msecs_to_jiffies(2000) + +enum { + BAM_DMUX_CMD_DATA, + BAM_DMUX_CMD_OPEN, + BAM_DMUX_CMD_CLOSE, +}; + +enum { + BAM_DMUX_CH_DATA_0, + BAM_DMUX_CH_DATA_1, + BAM_DMUX_CH_DATA_2, + BAM_DMUX_CH_DATA_3, + BAM_DMUX_CH_DATA_4, + BAM_DMUX_CH_DATA_5, + BAM_DMUX_CH_DATA_6, + BAM_DMUX_CH_DATA_7, + BAM_DMUX_NUM_CH +}; + +struct bam_dmux_hdr { + u16 magic; + u8 signal; + u8 cmd; + u8 pad; + u8 ch; + u16 len; +}; + +struct bam_dmux_skb_dma { + struct bam_dmux *dmux; + struct sk_buff *skb; + dma_addr_t addr; +}; + +struct bam_dmux { + struct device *dev; + + int pc_irq; + bool pc_state, pc_ack_state; + struct qcom_smem_state *pc, *pc_ack; + u32 pc_mask, pc_ack_mask; + wait_queue_head_t pc_wait; + struct completion pc_ack_completion; + + struct dma_chan *rx, *tx; + struct bam_dmux_skb_dma rx_skbs[BAM_DMUX_NUM_SKB]; + struct bam_dmux_skb_dma tx_skbs[BAM_DMUX_NUM_SKB]; + spinlock_t tx_lock; /* Protect tx_skbs, tx_next_skb */ + unsigned int tx_next_skb; + atomic_long_t tx_deferred_skb; + struct work_struct tx_wakeup_work; + + DECLARE_BITMAP(remote_channels, BAM_DMUX_NUM_CH); + struct work_struct register_netdev_work; + struct net_device *netdevs[BAM_DMUX_NUM_CH]; +}; + +struct bam_dmux_netdev { + struct bam_dmux *dmux; + u8 ch; +}; + +static void bam_dmux_pc_vote(struct bam_dmux *dmux, bool enable) +{ + reinit_completion(&dmux->pc_ack_completion); + qcom_smem_state_update_bits(dmux->pc, dmux->pc_mask, + enable ? dmux->pc_mask : 0); +} + +static void bam_dmux_pc_ack(struct bam_dmux *dmux) +{ + qcom_smem_state_update_bits(dmux->pc_ack, dmux->pc_ack_mask, + dmux->pc_ack_state ? 0 : dmux->pc_ack_mask); + dmux->pc_ack_state = !dmux->pc_ack_state; +} + +static bool bam_dmux_skb_dma_map(struct bam_dmux_skb_dma *skb_dma, + enum dma_data_direction dir) +{ + struct device *dev = skb_dma->dmux->dev; + + skb_dma->addr = dma_map_single(dev, skb_dma->skb->data, skb_dma->skb->len, dir); + if (dma_mapping_error(dev, skb_dma->addr)) { + dev_err(dev, "Failed to DMA map buffer\n"); + skb_dma->addr = 0; + return false; + } + + return true; +} + +static void bam_dmux_skb_dma_unmap(struct bam_dmux_skb_dma *skb_dma, + enum dma_data_direction dir) +{ + dma_unmap_single(skb_dma->dmux->dev, skb_dma->addr, skb_dma->skb->len, dir); + skb_dma->addr = 0; +} + +static void bam_dmux_tx_wake_queues(struct bam_dmux *dmux) +{ + int i; + + dev_dbg(dmux->dev, "wake queues\n"); + + for (i = 0; i < BAM_DMUX_NUM_CH; ++i) { + struct net_device *netdev = dmux->netdevs[i]; + + if (netdev && netif_running(netdev)) + netif_wake_queue(netdev); + } +} + +static void bam_dmux_tx_stop_queues(struct bam_dmux *dmux) +{ + int i; + + dev_dbg(dmux->dev, "stop queues\n"); + + for (i = 0; i < BAM_DMUX_NUM_CH; ++i) { + struct net_device *netdev = dmux->netdevs[i]; + + if (netdev) + netif_stop_queue(netdev); + } +} + +static void bam_dmux_tx_done(struct bam_dmux_skb_dma *skb_dma) +{ + struct bam_dmux *dmux = skb_dma->dmux; + unsigned long flags; + + pm_runtime_mark_last_busy(dmux->dev); + pm_runtime_put_autosuspend(dmux->dev); + + if (skb_dma->addr) + bam_dmux_skb_dma_unmap(skb_dma, DMA_TO_DEVICE); + + spin_lock_irqsave(&dmux->tx_lock, flags); + skb_dma->skb = NULL; + if (skb_dma == &dmux->tx_skbs[dmux->tx_next_skb % BAM_DMUX_NUM_SKB]) + bam_dmux_tx_wake_queues(dmux); + spin_unlock_irqrestore(&dmux->tx_lock, flags); +} + +static void bam_dmux_tx_callback(void *data) +{ + struct bam_dmux_skb_dma *skb_dma = data; + struct sk_buff *skb = skb_dma->skb; + + bam_dmux_tx_done(skb_dma); + dev_consume_skb_any(skb); +} + +static bool bam_dmux_skb_dma_submit_tx(struct bam_dmux_skb_dma *skb_dma) +{ + struct bam_dmux *dmux = skb_dma->dmux; + struct dma_async_tx_descriptor *desc; + + desc = dmaengine_prep_slave_single(dmux->tx, skb_dma->addr, + skb_dma->skb->len, DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT); + if (!desc) { + dev_err(dmux->dev, "Failed to prepare TX DMA buffer\n"); + return false; + } + + desc->callback = bam_dmux_tx_callback; + desc->callback_param = skb_dma; + desc->cookie = dmaengine_submit(desc); + return true; +} + +static struct bam_dmux_skb_dma * +bam_dmux_tx_queue(struct bam_dmux *dmux, struct sk_buff *skb) +{ + struct bam_dmux_skb_dma *skb_dma; + unsigned long flags; + + spin_lock_irqsave(&dmux->tx_lock, flags); + + skb_dma = &dmux->tx_skbs[dmux->tx_next_skb % BAM_DMUX_NUM_SKB]; + if (skb_dma->skb) { + bam_dmux_tx_stop_queues(dmux); + spin_unlock_irqrestore(&dmux->tx_lock, flags); + return NULL; + } + skb_dma->skb = skb; + + dmux->tx_next_skb++; + if (dmux->tx_skbs[dmux->tx_next_skb % BAM_DMUX_NUM_SKB].skb) + bam_dmux_tx_stop_queues(dmux); + + spin_unlock_irqrestore(&dmux->tx_lock, flags); + return skb_dma; +} + +static int bam_dmux_send_cmd(struct bam_dmux_netdev *bndev, u8 cmd) +{ + struct bam_dmux *dmux = bndev->dmux; + struct bam_dmux_skb_dma *skb_dma; + struct bam_dmux_hdr *hdr; + struct sk_buff *skb; + int ret; + + skb = alloc_skb(sizeof(*hdr), GFP_KERNEL); + if (!skb) + return -ENOMEM; + + hdr = skb_put_zero(skb, sizeof(*hdr)); + hdr->magic = BAM_DMUX_HDR_MAGIC; + hdr->cmd = cmd; + hdr->ch = bndev->ch; + + skb_dma = bam_dmux_tx_queue(dmux, skb); + if (!skb_dma) { + ret = -EAGAIN; + goto free_skb; + } + + ret = pm_runtime_get_sync(dmux->dev); + if (ret < 0) + goto tx_fail; + + if (!bam_dmux_skb_dma_map(skb_dma, DMA_TO_DEVICE)) { + ret = -ENOMEM; + goto tx_fail; + } + + if (!bam_dmux_skb_dma_submit_tx(skb_dma)) { + ret = -EIO; + goto tx_fail; + } + + dma_async_issue_pending(dmux->tx); + return 0; + +tx_fail: + bam_dmux_tx_done(skb_dma); +free_skb: + dev_kfree_skb(skb); + return ret; +} + +static int bam_dmux_netdev_open(struct net_device *netdev) +{ + struct bam_dmux_netdev *bndev = netdev_priv(netdev); + int ret; + + ret = bam_dmux_send_cmd(bndev, BAM_DMUX_CMD_OPEN); + if (ret) + return ret; + + netif_start_queue(netdev); + return 0; +} + +static int bam_dmux_netdev_stop(struct net_device *netdev) +{ + struct bam_dmux_netdev *bndev = netdev_priv(netdev); + + netif_stop_queue(netdev); + bam_dmux_send_cmd(bndev, BAM_DMUX_CMD_CLOSE); + return 0; +} + +static unsigned int needed_room(unsigned int avail, unsigned int needed) +{ + if (avail >= needed) + return 0; + return needed - avail; +} + +static int bam_dmux_tx_prepare_skb(struct bam_dmux_netdev *bndev, + struct sk_buff *skb) +{ + unsigned int head = needed_room(skb_headroom(skb), BAM_DMUX_HDR_SIZE); + unsigned int pad = sizeof(u32) - skb->len % sizeof(u32); + unsigned int tail = needed_room(skb_tailroom(skb), pad); + struct bam_dmux_hdr *hdr; + int ret; + + if (head || tail || skb_cloned(skb)) { + ret = pskb_expand_head(skb, head, tail, GFP_ATOMIC); + if (ret) + return ret; + } + + hdr = skb_push(skb, sizeof(*hdr)); + hdr->magic = BAM_DMUX_HDR_MAGIC; + hdr->signal = 0; + hdr->cmd = BAM_DMUX_CMD_DATA; + hdr->pad = pad; + hdr->ch = bndev->ch; + hdr->len = skb->len - sizeof(*hdr); + if (pad) + skb_put_zero(skb, pad); + + return 0; +} + +static netdev_tx_t bam_dmux_netdev_start_xmit(struct sk_buff *skb, + struct net_device *netdev) +{ + struct bam_dmux_netdev *bndev = netdev_priv(netdev); + struct bam_dmux *dmux = bndev->dmux; + struct bam_dmux_skb_dma *skb_dma; + int active, ret; + + skb_dma = bam_dmux_tx_queue(dmux, skb); + if (!skb_dma) + return NETDEV_TX_BUSY; + + active = pm_runtime_get(dmux->dev); + if (active < 0 && active != -EINPROGRESS) + goto drop; + + ret = bam_dmux_tx_prepare_skb(bndev, skb); + if (ret) + goto drop; + + if (!bam_dmux_skb_dma_map(skb_dma, DMA_TO_DEVICE)) + goto drop; + + if (active <= 0) { + /* Cannot sleep here so mark skb for wakeup handler and return */ + if (!atomic_long_fetch_or(BIT(skb_dma - dmux->tx_skbs), + &dmux->tx_deferred_skb)) + queue_pm_work(&dmux->tx_wakeup_work); + return NETDEV_TX_OK; + } + + if (!bam_dmux_skb_dma_submit_tx(skb_dma)) + goto drop; + + dma_async_issue_pending(dmux->tx); + return NETDEV_TX_OK; + +drop: + bam_dmux_tx_done(skb_dma); + dev_kfree_skb_any(skb); + return NETDEV_TX_OK; +} + +static void bam_dmux_tx_wakeup_work(struct work_struct *work) +{ + struct bam_dmux *dmux = container_of(work, struct bam_dmux, tx_wakeup_work); + unsigned long pending; + int ret, i; + + ret = pm_runtime_resume_and_get(dmux->dev); + if (ret < 0) { + dev_err(dmux->dev, "Failed to resume: %d\n", ret); + return; + } + + pending = atomic_long_xchg(&dmux->tx_deferred_skb, 0); + if (!pending) + goto out; + + dev_dbg(dmux->dev, "pending skbs after wakeup: %#lx\n", pending); + for_each_set_bit(i, &pending, BAM_DMUX_NUM_SKB) { + bam_dmux_skb_dma_submit_tx(&dmux->tx_skbs[i]); + } + dma_async_issue_pending(dmux->tx); + +out: + pm_runtime_mark_last_busy(dmux->dev); + pm_runtime_put_autosuspend(dmux->dev); +} + +static const struct net_device_ops bam_dmux_ops = { + .ndo_open = bam_dmux_netdev_open, + .ndo_stop = bam_dmux_netdev_stop, + .ndo_start_xmit = bam_dmux_netdev_start_xmit, +}; + +static const struct device_type wwan_type = { + .name = "wwan", +}; + +static void bam_dmux_netdev_setup(struct net_device *dev) +{ + dev->netdev_ops = &bam_dmux_ops; + + dev->type = ARPHRD_RAWIP; + SET_NETDEV_DEVTYPE(dev, &wwan_type); + dev->flags = IFF_POINTOPOINT | IFF_NOARP; + + dev->mtu = ETH_DATA_LEN; + dev->max_mtu = BAM_DMUX_MAX_DATA_SIZE; + dev->needed_headroom = sizeof(struct bam_dmux_hdr); + dev->needed_tailroom = sizeof(u32); /* word-aligned */ + dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN; + + /* This perm addr will be used as interface identifier by IPv6 */ + dev->addr_assign_type = NET_ADDR_RANDOM; + eth_random_addr(dev->perm_addr); +} + +static void bam_dmux_register_netdev_work(struct work_struct *work) +{ + struct bam_dmux *dmux = container_of(work, struct bam_dmux, register_netdev_work); + struct bam_dmux_netdev *bndev; + struct net_device *netdev; + int ch, ret; + + for_each_set_bit(ch, dmux->remote_channels, BAM_DMUX_NUM_CH) { + if (dmux->netdevs[ch]) + continue; + + netdev = alloc_netdev(sizeof(*bndev), "rmnet%d", NET_NAME_ENUM, + bam_dmux_netdev_setup); + if (!netdev) + return; + + SET_NETDEV_DEV(netdev, dmux->dev); + netdev->dev_port = ch; + + bndev = netdev_priv(netdev); + bndev->dmux = dmux; + bndev->ch = ch; + + ret = register_netdev(netdev); + if (ret) { + dev_err(dmux->dev, "Failed to register netdev for channel %u: %d\n", + ch, ret); + free_netdev(netdev); + return; + } + + dmux->netdevs[ch] = netdev; + } +} + +static void bam_dmux_rx_callback(void *data); + +static bool bam_dmux_skb_dma_submit_rx(struct bam_dmux_skb_dma *skb_dma) +{ + struct bam_dmux *dmux = skb_dma->dmux; + struct dma_async_tx_descriptor *desc; + + desc = dmaengine_prep_slave_single(dmux->rx, skb_dma->addr, + skb_dma->skb->len, DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT); + if (!desc) { + dev_err(dmux->dev, "Failed to prepare RX DMA buffer\n"); + return false; + } + + desc->callback = bam_dmux_rx_callback; + desc->callback_param = skb_dma; + desc->cookie = dmaengine_submit(desc); + return true; +} + +static bool bam_dmux_skb_dma_queue_rx(struct bam_dmux_skb_dma *skb_dma, gfp_t gfp) +{ + if (!skb_dma->skb) { + skb_dma->skb = __netdev_alloc_skb(NULL, BAM_DMUX_BUFFER_SIZE, gfp); + if (!skb_dma->skb) + return false; + skb_put(skb_dma->skb, BAM_DMUX_BUFFER_SIZE); + } + + return bam_dmux_skb_dma_map(skb_dma, DMA_FROM_DEVICE) && + bam_dmux_skb_dma_submit_rx(skb_dma); +} + +static void bam_dmux_cmd_data(struct bam_dmux_skb_dma *skb_dma) +{ + struct bam_dmux *dmux = skb_dma->dmux; + struct sk_buff *skb = skb_dma->skb; + struct bam_dmux_hdr *hdr = (struct bam_dmux_hdr *)skb->data; + struct net_device *netdev = dmux->netdevs[hdr->ch]; + + if (!netdev || !netif_running(netdev)) { + dev_warn(dmux->dev, "Data for inactive channel %u\n", hdr->ch); + return; + } + + if (hdr->len > BAM_DMUX_MAX_DATA_SIZE) { + dev_err(dmux->dev, "Data larger than buffer? (%u > %u)\n", + hdr->len, (u16)BAM_DMUX_MAX_DATA_SIZE); + return; + } + + skb_dma->skb = NULL; /* Hand over to network stack */ + + skb_pull(skb, sizeof(*hdr)); + skb_trim(skb, hdr->len); + skb->dev = netdev; + + /* Only Raw-IP/QMAP is supported by this driver */ + switch (skb->data[0] & 0xf0) { + case 0x40: + skb->protocol = htons(ETH_P_IP); + break; + case 0x60: + skb->protocol = htons(ETH_P_IPV6); + break; + default: + skb->protocol = htons(ETH_P_MAP); + break; + } + + netif_receive_skb(skb); +} + +static void bam_dmux_cmd_open(struct bam_dmux *dmux, struct bam_dmux_hdr *hdr) +{ + struct net_device *netdev = dmux->netdevs[hdr->ch]; + + dev_dbg(dmux->dev, "open channel: %u\n", hdr->ch); + + if (__test_and_set_bit(hdr->ch, dmux->remote_channels)) { + dev_warn(dmux->dev, "Channel already open: %u\n", hdr->ch); + return; + } + + if (netdev) { + netif_device_attach(netdev); + } else { + /* Cannot sleep here, schedule work to register the netdev */ + schedule_work(&dmux->register_netdev_work); + } +} + +static void bam_dmux_cmd_close(struct bam_dmux *dmux, struct bam_dmux_hdr *hdr) +{ + struct net_device *netdev = dmux->netdevs[hdr->ch]; + + dev_dbg(dmux->dev, "close channel: %u\n", hdr->ch); + + if (!__test_and_clear_bit(hdr->ch, dmux->remote_channels)) { + dev_err(dmux->dev, "Channel not open: %u\n", hdr->ch); + return; + } + + if (netdev) + netif_device_detach(netdev); +} + +static void bam_dmux_rx_callback(void *data) +{ + struct bam_dmux_skb_dma *skb_dma = data; + struct bam_dmux *dmux = skb_dma->dmux; + struct sk_buff *skb = skb_dma->skb; + struct bam_dmux_hdr *hdr = (struct bam_dmux_hdr *)skb->data; + + bam_dmux_skb_dma_unmap(skb_dma, DMA_FROM_DEVICE); + + if (hdr->magic != BAM_DMUX_HDR_MAGIC) { + dev_err(dmux->dev, "Invalid magic in header: %#x\n", hdr->magic); + goto out; + } + + if (hdr->ch >= BAM_DMUX_NUM_CH) { + dev_dbg(dmux->dev, "Unsupported channel: %u\n", hdr->ch); + goto out; + } + + switch (hdr->cmd) { + case BAM_DMUX_CMD_DATA: + bam_dmux_cmd_data(skb_dma); + break; + case BAM_DMUX_CMD_OPEN: + bam_dmux_cmd_open(dmux, hdr); + break; + case BAM_DMUX_CMD_CLOSE: + bam_dmux_cmd_close(dmux, hdr); + break; + default: + dev_err(dmux->dev, "Unsupported command %u on channel %u\n", + hdr->cmd, hdr->ch); + break; + } + +out: + if (bam_dmux_skb_dma_queue_rx(skb_dma, GFP_ATOMIC)) + dma_async_issue_pending(dmux->rx); +} + +static bool bam_dmux_power_on(struct bam_dmux *dmux) +{ + struct device *dev = dmux->dev; + struct dma_slave_config dma_rx_conf = { + .direction = DMA_DEV_TO_MEM, + .src_maxburst = BAM_DMUX_BUFFER_SIZE, + }; + int i; + + dmux->rx = dma_request_chan(dev, "rx"); + if (IS_ERR(dmux->rx)) { + dev_err(dev, "Failed to request RX DMA channel: %pe\n", dmux->rx); + dmux->rx = NULL; + return false; + } + dmaengine_slave_config(dmux->rx, &dma_rx_conf); + + for (i = 0; i < BAM_DMUX_NUM_SKB; i++) { + if (!bam_dmux_skb_dma_queue_rx(&dmux->rx_skbs[i], GFP_KERNEL)) + return false; + } + dma_async_issue_pending(dmux->rx); + + return true; +} + +static void bam_dmux_free_skbs(struct bam_dmux_skb_dma skbs[], + enum dma_data_direction dir) +{ + int i; + + for (i = 0; i < BAM_DMUX_NUM_SKB; i++) { + struct bam_dmux_skb_dma *skb_dma = &skbs[i]; + + if (skb_dma->addr) + bam_dmux_skb_dma_unmap(skb_dma, dir); + if (skb_dma->skb) { + dev_kfree_skb(skb_dma->skb); + skb_dma->skb = NULL; + } + } +} + +static void bam_dmux_power_off(struct bam_dmux *dmux) +{ + if (dmux->tx) { + dmaengine_terminate_sync(dmux->tx); + dma_release_channel(dmux->tx); + dmux->tx = NULL; + } + + if (dmux->rx) { + dmaengine_terminate_sync(dmux->rx); + dma_release_channel(dmux->rx); + dmux->rx = NULL; + } + + bam_dmux_free_skbs(dmux->rx_skbs, DMA_FROM_DEVICE); +} + +static irqreturn_t bam_dmux_pc_irq(int irq, void *data) +{ + struct bam_dmux *dmux = data; + bool new_state = !dmux->pc_state; + + dev_dbg(dmux->dev, "pc: %u\n", new_state); + + if (new_state) { + if (bam_dmux_power_on(dmux)) + bam_dmux_pc_ack(dmux); + else + bam_dmux_power_off(dmux); + } else { + bam_dmux_power_off(dmux); + bam_dmux_pc_ack(dmux); + } + + dmux->pc_state = new_state; + wake_up_all(&dmux->pc_wait); + + return IRQ_HANDLED; +} + +static irqreturn_t bam_dmux_pc_ack_irq(int irq, void *data) +{ + struct bam_dmux *dmux = data; + + dev_dbg(dmux->dev, "pc ack\n"); + complete_all(&dmux->pc_ack_completion); + + return IRQ_HANDLED; +} + +static int bam_dmux_runtime_suspend(struct device *dev) +{ + struct bam_dmux *dmux = dev_get_drvdata(dev); + + dev_dbg(dev, "runtime suspend\n"); + bam_dmux_pc_vote(dmux, false); + + return 0; +} + +static int __maybe_unused bam_dmux_runtime_resume(struct device *dev) +{ + struct bam_dmux *dmux = dev_get_drvdata(dev); + + dev_dbg(dev, "runtime resume\n"); + + /* Wait until previous power down was acked */ + if (!wait_for_completion_timeout(&dmux->pc_ack_completion, + BAM_DMUX_REMOTE_TIMEOUT)) + return -ETIMEDOUT; + + /* Vote for power state */ + bam_dmux_pc_vote(dmux, true); + + /* Wait for ack */ + if (!wait_for_completion_timeout(&dmux->pc_ack_completion, + BAM_DMUX_REMOTE_TIMEOUT)) { + bam_dmux_pc_vote(dmux, false); + return -ETIMEDOUT; + } + + /* Wait until we're up */ + if (!wait_event_timeout(dmux->pc_wait, dmux->pc_state, + BAM_DMUX_REMOTE_TIMEOUT)) { + bam_dmux_pc_vote(dmux, false); + return -ETIMEDOUT; + } + + /* Ensure that we actually initialized successfully */ + if (!dmux->rx) { + bam_dmux_pc_vote(dmux, false); + return -ENXIO; + } + + /* Request TX channel if necessary */ + if (dmux->tx) + return 0; + + dmux->tx = dma_request_chan(dev, "tx"); + if (IS_ERR(dmux->rx)) { + dev_err(dev, "Failed to request TX DMA channel: %pe\n", dmux->tx); + dmux->tx = NULL; + bam_dmux_runtime_suspend(dev); + return -ENXIO; + } + + return 0; +} + +static int bam_dmux_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct bam_dmux *dmux; + int ret, pc_ack_irq, i; + unsigned int bit; + + dmux = devm_kzalloc(dev, sizeof(*dmux), GFP_KERNEL); + if (!dmux) + return -ENOMEM; + + dmux->dev = dev; + platform_set_drvdata(pdev, dmux); + + dmux->pc_irq = platform_get_irq_byname(pdev, "pc"); + if (dmux->pc_irq < 0) + return dmux->pc_irq; + + pc_ack_irq = platform_get_irq_byname(pdev, "pc-ack"); + if (pc_ack_irq < 0) + return pc_ack_irq; + + dmux->pc = devm_qcom_smem_state_get(dev, "pc", &bit); + if (IS_ERR(dmux->pc)) + return dev_err_probe(dev, PTR_ERR(dmux->pc), + "Failed to get pc state\n"); + dmux->pc_mask = BIT(bit); + + dmux->pc_ack = devm_qcom_smem_state_get(dev, "pc-ack", &bit); + if (IS_ERR(dmux->pc_ack)) + return dev_err_probe(dev, PTR_ERR(dmux->pc_ack), + "Failed to get pc-ack state\n"); + dmux->pc_ack_mask = BIT(bit); + + init_waitqueue_head(&dmux->pc_wait); + init_completion(&dmux->pc_ack_completion); + complete_all(&dmux->pc_ack_completion); + + spin_lock_init(&dmux->tx_lock); + INIT_WORK(&dmux->tx_wakeup_work, bam_dmux_tx_wakeup_work); + INIT_WORK(&dmux->register_netdev_work, bam_dmux_register_netdev_work); + + for (i = 0; i < BAM_DMUX_NUM_SKB; i++) { + dmux->rx_skbs[i].dmux = dmux; + dmux->tx_skbs[i].dmux = dmux; + } + + /* Runtime PM manages our own power vote. + * Note that the RX path may be active even if we are runtime suspended, + * since it is controlled by the remote side. + */ + pm_runtime_set_autosuspend_delay(dev, BAM_DMUX_AUTOSUSPEND_DELAY); + pm_runtime_use_autosuspend(dev); + pm_runtime_enable(dev); + + ret = devm_request_threaded_irq(dev, pc_ack_irq, NULL, bam_dmux_pc_ack_irq, + IRQF_ONESHOT, NULL, dmux); + if (ret) + return ret; + + ret = devm_request_threaded_irq(dev, dmux->pc_irq, NULL, bam_dmux_pc_irq, + IRQF_ONESHOT, NULL, dmux); + if (ret) + return ret; + + ret = irq_get_irqchip_state(dmux->pc_irq, IRQCHIP_STATE_LINE_LEVEL, + &dmux->pc_state); + if (ret) + return ret; + + /* Check if remote finished initialization before us */ + if (dmux->pc_state) { + if (bam_dmux_power_on(dmux)) + bam_dmux_pc_ack(dmux); + else + bam_dmux_power_off(dmux); + } + + return 0; +} + +static int bam_dmux_remove(struct platform_device *pdev) +{ + struct bam_dmux *dmux = platform_get_drvdata(pdev); + struct device *dev = dmux->dev; + LIST_HEAD(list); + int i; + + /* Unregister network interfaces */ + cancel_work_sync(&dmux->register_netdev_work); + rtnl_lock(); + for (i = 0; i < BAM_DMUX_NUM_CH; ++i) + if (dmux->netdevs[i]) + unregister_netdevice_queue(dmux->netdevs[i], &list); + unregister_netdevice_many(&list); + rtnl_unlock(); + cancel_work_sync(&dmux->tx_wakeup_work); + + /* Drop our own power vote */ + pm_runtime_disable(dev); + pm_runtime_dont_use_autosuspend(dev); + bam_dmux_runtime_suspend(dev); + pm_runtime_set_suspended(dev); + + /* Try to wait for remote side to drop power vote */ + if (!wait_event_timeout(dmux->pc_wait, !dmux->rx, BAM_DMUX_REMOTE_TIMEOUT)) + dev_err(dev, "Timed out waiting for remote side to suspend\n"); + + /* Make sure everything is cleaned up before we return */ + disable_irq(dmux->pc_irq); + bam_dmux_power_off(dmux); + bam_dmux_free_skbs(dmux->tx_skbs, DMA_TO_DEVICE); + + return 0; +} + +static const struct dev_pm_ops bam_dmux_pm_ops = { + SET_RUNTIME_PM_OPS(bam_dmux_runtime_suspend, bam_dmux_runtime_resume, NULL) +}; + +static const struct of_device_id bam_dmux_of_match[] = { + { .compatible = "qcom,bam-dmux" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, bam_dmux_of_match); + +static struct platform_driver bam_dmux_driver = { + .probe = bam_dmux_probe, + .remove = bam_dmux_remove, + .driver = { + .name = "bam-dmux", + .pm = &bam_dmux_pm_ops, + .of_match_table = bam_dmux_of_match, + }, +}; +module_platform_driver(bam_dmux_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("Qualcomm BAM-DMUX WWAN Network Driver"); +MODULE_AUTHOR("Stephan Gerhold ");