From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 DF302C282CB for ; Fri, 8 Feb 2019 18:59:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8ADF2077B for ; Fri, 8 Feb 2019 18:59:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="febWi4Hk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727236AbfBHS7t (ORCPT ); Fri, 8 Feb 2019 13:59:49 -0500 Received: from hqemgate14.nvidia.com ([216.228.121.143]:17697 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726020AbfBHS7r (ORCPT ); Fri, 8 Feb 2019 13:59:47 -0500 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Fri, 08 Feb 2019 10:59:50 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Fri, 08 Feb 2019 10:59:46 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Fri, 08 Feb 2019 10:59:46 -0800 Received: from HQMAIL107.nvidia.com (172.20.187.13) by HQMAIL106.nvidia.com (172.18.146.12) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 8 Feb 2019 18:59:45 +0000 Received: from hqnvemgw01.nvidia.com (172.20.150.20) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1395.4 via Frontend Transport; Fri, 8 Feb 2019 18:59:46 +0000 Received: from skomatineni-linux.nvidia.com (Not Verified[10.2.171.121]) by hqnvemgw01.nvidia.com with Trustwave SEG (v7,5,8,10121) id ; Fri, 08 Feb 2019 10:59:45 -0800 From: Sowjanya Komatineni To: , , , , CC: , , , , , , Sowjanya Komatineni Subject: [PATCH V18 2/6] i2c: tegra: add bus clear Master Support Date: Fri, 8 Feb 2019 10:59:38 -0800 Message-ID: <1549652382-5476-2-git-send-email-skomatineni@nvidia.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1549652382-5476-1-git-send-email-skomatineni@nvidia.com> References: <1549652382-5476-1-git-send-email-skomatineni@nvidia.com> X-NVConfidentiality: public MIME-Version: 1.0 Content-Type: text/plain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1549652390; bh=4PIRZnsvuLUEzaMYgXlW9wfl7GPHmYtQVsTMT5qN/Uc=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:X-NVConfidentiality:MIME-Version: Content-Type; b=febWi4HkfqaNd7Mz55tY0znJn7bk+tG/pohh+ZiSkGY/139eH/h1zDkHVKxoIQ/v2 Dy51Ber72dg++K0xI9ik/gutWZKe/If9K3GNk4so/XqVH7drZjALqPMd/TTR7KFXWM adqpdu9Oj0XxgiaGIrgcxYtwi1dMg+ZHwCRh+dMyM5E8iEzu9EndFNdlxd0Nf6bWZi UcHi4Wd0IcMS9t7bmOrXBja9Cqk2lKQrcl+zdvq+VZMxnBdkXTFCVI0tdI0bZp1gaH 4MUl1EOz7ugvOrusJB+Kyve2O34z4hCYjh31Xou0gVvwnqehFMKVn9edZMqh5ukT/5 u5dc0xXc7mFAw== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Bus clear feature of Tegra I2C controller helps to recover from bus hang when I2C master loses the bus arbitration due to the slave device holding SDA LOW continuously for some unknown reasons. Per I2C specification, the device that held the bus LOW should release it within 9 clock pulses. During bus clear operation, Tegra I2C controller sends 9 clock pulses and terminates the transaction with STOP condition. Upon successful bus clear operation, bus goes to idle state and driver retries the transaction. Acked-by: Thierry Reding Reviewed-by: Dmitry Osipenko Signed-off-by: Sowjanya Komatineni --- [V9/V10/V11/V12/V13/V14/V15/V16/V17/V18] : Rebased to 5.0-rc4 [V5/V6/V7/V8] : Same as V4 [V4] : Added I2C Bus Clear support patch to this version of series. drivers/i2c/busses/i2c-tegra.c | 73 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index 79c6aa87499b..3758c7a2c781 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -51,6 +51,7 @@ #define I2C_FIFO_STATUS_RX_SHIFT 0 #define I2C_INT_MASK 0x064 #define I2C_INT_STATUS 0x068 +#define I2C_INT_BUS_CLR_DONE BIT(11) #define I2C_INT_PACKET_XFER_COMPLETE BIT(7) #define I2C_INT_ALL_PACKETS_XFER_COMPLETE BIT(6) #define I2C_INT_TX_FIFO_OVERFLOW BIT(5) @@ -93,6 +94,15 @@ #define I2C_HEADER_MASTER_ADDR_SHIFT 12 #define I2C_HEADER_SLAVE_ADDR_SHIFT 1 +#define I2C_BUS_CLEAR_CNFG 0x084 +#define I2C_BC_SCLK_THRESHOLD 9 +#define I2C_BC_SCLK_THRESHOLD_SHIFT 16 +#define I2C_BC_STOP_COND BIT(2) +#define I2C_BC_TERMINATE BIT(1) +#define I2C_BC_ENABLE BIT(0) +#define I2C_BUS_CLEAR_STATUS 0x088 +#define I2C_BC_STATUS BIT(0) + #define I2C_CONFIG_LOAD 0x08C #define I2C_MSTR_CONFIG_LOAD BIT(0) #define I2C_SLV_CONFIG_LOAD BIT(1) @@ -154,6 +164,8 @@ enum msg_end_type { * be transferred in one go. * @quirks: i2c adapter quirks for limiting write/read transfer size and not * allowing 0 length transfers. + * @supports_bus_clear: Bus Clear support to recover from bus hang during + * SDA stuck low from device for some unknown reasons. */ struct tegra_i2c_hw_feature { bool has_continue_xfer_support; @@ -167,6 +179,7 @@ struct tegra_i2c_hw_feature { bool has_slcg_override_reg; bool has_mst_fifo; const struct i2c_adapter_quirks *quirks; + bool supports_bus_clear; }; /** @@ -640,6 +653,13 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) goto err; } + /* + * I2C transfer is terminated during the bus clear so skip + * processing the other interrupts. + */ + if (i2c_dev->hw->supports_bus_clear && (status & I2C_INT_BUS_CLR_DONE)) + goto err; + if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) { if (i2c_dev->msg_buf_remaining) tegra_i2c_empty_rx_fifo(i2c_dev); @@ -668,6 +688,8 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ | I2C_INT_RX_FIFO_DATA_REQ); + if (i2c_dev->hw->supports_bus_clear) + tegra_i2c_mask_irq(i2c_dev, I2C_INT_BUS_CLR_DONE); i2c_writel(i2c_dev, status, I2C_INT_STATUS); if (i2c_dev->is_dvc) dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS); @@ -678,6 +700,43 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) return IRQ_HANDLED; } +static int tegra_i2c_issue_bus_clear(struct tegra_i2c_dev *i2c_dev) +{ + int err; + unsigned long time_left; + u32 reg; + + if (i2c_dev->hw->supports_bus_clear) { + reinit_completion(&i2c_dev->msg_complete); + reg = (I2C_BC_SCLK_THRESHOLD << I2C_BC_SCLK_THRESHOLD_SHIFT) | + I2C_BC_STOP_COND | I2C_BC_TERMINATE; + i2c_writel(i2c_dev, reg, I2C_BUS_CLEAR_CNFG); + if (i2c_dev->hw->has_config_load_reg) { + err = tegra_i2c_wait_for_config_load(i2c_dev); + if (err) + return err; + } + reg |= I2C_BC_ENABLE; + i2c_writel(i2c_dev, reg, I2C_BUS_CLEAR_CNFG); + tegra_i2c_unmask_irq(i2c_dev, I2C_INT_BUS_CLR_DONE); + + time_left = wait_for_completion_timeout(&i2c_dev->msg_complete, + TEGRA_I2C_TIMEOUT); + if (time_left == 0) { + dev_err(i2c_dev->dev, "timed out for bus clear\n"); + return -ETIMEDOUT; + } + reg = i2c_readl(i2c_dev, I2C_BUS_CLEAR_STATUS); + if (!(reg & I2C_BC_STATUS)) { + dev_err(i2c_dev->dev, + "un-recovered arbitration lost\n"); + return -EIO; + } + } + + return -EAGAIN; +} + static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, struct i2c_msg *msg, enum msg_end_type end_state) { @@ -759,6 +818,13 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, return 0; tegra_i2c_init(i2c_dev); + /* start recovery upon arbitration loss in single master mode */ + if (i2c_dev->msg_err == I2C_ERR_ARBITRATION_LOST) { + if (!i2c_dev->is_multimaster_mode) + return tegra_i2c_issue_bus_clear(i2c_dev); + return -EAGAIN; + } + if (i2c_dev->msg_err == I2C_ERR_NO_ACK) { if (msg->flags & I2C_M_IGNORE_NAK) return 0; @@ -853,6 +919,7 @@ static const struct tegra_i2c_hw_feature tegra20_i2c_hw = { .has_slcg_override_reg = false, .has_mst_fifo = false, .quirks = &tegra_i2c_quirks, + .supports_bus_clear = false, }; static const struct tegra_i2c_hw_feature tegra30_i2c_hw = { @@ -867,6 +934,7 @@ static const struct tegra_i2c_hw_feature tegra30_i2c_hw = { .has_slcg_override_reg = false, .has_mst_fifo = false, .quirks = &tegra_i2c_quirks, + .supports_bus_clear = false, }; static const struct tegra_i2c_hw_feature tegra114_i2c_hw = { @@ -881,6 +949,7 @@ static const struct tegra_i2c_hw_feature tegra114_i2c_hw = { .has_slcg_override_reg = false, .has_mst_fifo = false, .quirks = &tegra_i2c_quirks, + .supports_bus_clear = true, }; static const struct tegra_i2c_hw_feature tegra124_i2c_hw = { @@ -895,6 +964,7 @@ static const struct tegra_i2c_hw_feature tegra124_i2c_hw = { .has_slcg_override_reg = true, .has_mst_fifo = false, .quirks = &tegra_i2c_quirks, + .supports_bus_clear = true, }; static const struct tegra_i2c_hw_feature tegra210_i2c_hw = { @@ -909,6 +979,7 @@ static const struct tegra_i2c_hw_feature tegra210_i2c_hw = { .has_slcg_override_reg = true, .has_mst_fifo = false, .quirks = &tegra_i2c_quirks, + .supports_bus_clear = true, }; static const struct tegra_i2c_hw_feature tegra194_i2c_hw = { @@ -923,6 +994,7 @@ static const struct tegra_i2c_hw_feature tegra194_i2c_hw = { .has_slcg_override_reg = true, .has_mst_fifo = true, .quirks = &tegra194_i2c_quirks, + .supports_bus_clear = true, }; /* Match table for of_platform binding */ @@ -974,6 +1046,7 @@ static int tegra_i2c_probe(struct platform_device *pdev) i2c_dev->base = base; i2c_dev->div_clk = div_clk; i2c_dev->adapter.algo = &tegra_i2c_algo; + i2c_dev->adapter.retries = 1; i2c_dev->irq = irq; i2c_dev->cont_id = pdev->id; i2c_dev->dev = &pdev->dev; -- 2.7.4