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[209.132.180.67]) by mx.google.com with ESMTP id s2si20263584plj.119.2017.04.05.03.32.44; Wed, 05 Apr 2017 03:32:45 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of stable-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org; spf=pass (google.com: best guess record for domain of stable-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933420AbdDEKcm (ORCPT + 6 others); Wed, 5 Apr 2017 06:32:42 -0400 Received: from mail-pf0-f177.google.com ([209.85.192.177]:34628 "EHLO mail-pf0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933086AbdDEKcl (ORCPT ); Wed, 5 Apr 2017 06:32:41 -0400 Received: by mail-pf0-f177.google.com with SMTP id 197so5592775pfv.1 for ; Wed, 05 Apr 2017 03:32:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=9kzwUdPxD7Tmaremnkx0FnAxJcom5K86C8c5v11yIxg=; b=P7KRl0oKxOoghAY33CuPS96iV6GF5HAId+yrtDMK4HYzegVLx7P1SD1JAB7d8XZ5uF A+ygRavY5Dkzed9dp4Ip7DRCqt0xlZ0UfvDO9QM2kRCsdqMMPfIQ4veFmDcVOsNKC+Bu LNBQWAeA8WN7oxqRKZKN/5VSU6wI7T9jRwpl4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=9kzwUdPxD7Tmaremnkx0FnAxJcom5K86C8c5v11yIxg=; b=nDwb21biEoG6LNx55l5AzPzZHIJtICs4yDQ3bZ9BciZA987WTLJPpT72LgCFux0RdQ vNde16uAPa6TIpCrmjPv38uglOGM0DnN83vt0lfgs4xdnZqks2nVrKYjgsyRjQ/kYIIj tTYOAcdUDAm3l9706YLeyIUm1yWTuz6RualvYk8iMxjriu5DaOBpS3j5H+G3rd68MXto /O8AiUWXPI8IAlLbEbrPLkRcmEsu1XMmqav0kdYdqJKU0mcAQIMH09dm54gVkQr+joby /H5Hx5NtDpDZCDrFYx/VwQBKvxbrfFjpFevD7URkkFN5kH6JhdO5hb4VZ+Bqc50BiYFj 2M/Q== X-Gm-Message-State: AFeK/H2soLDbaKo9L7xV84qr4r+m0JfbtEnj1tfnUucab7H5EWjapdDRPSELglYfJPt1aen8 X-Received: by 10.98.27.204 with SMTP id b195mr28647770pfb.154.1491388358915; Wed, 05 Apr 2017 03:32:38 -0700 (PDT) Received: from localhost.localdomain ([106.51.240.246]) by smtp.gmail.com with ESMTPSA id a62sm36732075pgc.60.2017.04.05.03.32.37 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 05 Apr 2017 03:32:38 -0700 (PDT) From: Amit Pundir To: stable@vger.kernel.org Cc: gregkh@linuxfoundation.org, =?utf-8?q?Noralf_Tr=C3=B8nnes?= , Wolfram Sang Subject: [PATCH v2 for-4.9 05/32] i2c: bcm2835: Fix hang for writing messages larger than 16 bytes Date: Wed, 5 Apr 2017 16:01:57 +0530 Message-Id: <1491388344-13521-6-git-send-email-amit.pundir@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1491388344-13521-1-git-send-email-amit.pundir@linaro.org> References: <1491388344-13521-1-git-send-email-amit.pundir@linaro.org> MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Noralf Trønnes Writing messages larger than the FIFO size results in a hang, rendering the machine unusable. This is because the RXD status flag is set on the first interrupt which results in bcm2835_drain_rxfifo() stealing bytes from the buffer. The controller continues to trigger interrupts waiting for the missing bytes, but bcm2835_fill_txfifo() has none to give. In this situation wait_for_completion_timeout() apparently is unable to stop the madness. The BCM2835 ARM Peripherals datasheet has this to say about the flags: TXD: is set when the FIFO has space for at least one byte of data. RXD: is set when the FIFO contains at least one byte of data. TXW: is set during a write transfer and the FIFO is less than full. RXR: is set during a read transfer and the FIFO is or more full. Implementing the logic from the downstream i2c-bcm2708 driver solved the hang problem. Signed-off-by: Noralf Trønnes Reviewed-by: Eric Anholt Reviewed-by: Martin Sperl Signed-off-by: Wolfram Sang (cherry picked from commit e2474541032db65d02bf88b6a8c2f954654b443f) Signed-off-by: Amit Pundir --- drivers/i2c/busses/i2c-bcm2835.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) -- 2.7.4 diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c index d4f3239..f283b71 100644 --- a/drivers/i2c/busses/i2c-bcm2835.c +++ b/drivers/i2c/busses/i2c-bcm2835.c @@ -64,6 +64,7 @@ struct bcm2835_i2c_dev { int irq; struct i2c_adapter adapter; struct completion completion; + struct i2c_msg *curr_msg; u32 msg_err; u8 *msg_buf; size_t msg_buf_remaining; @@ -126,14 +127,13 @@ static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data) return IRQ_HANDLED; } - if (val & BCM2835_I2C_S_RXD) { - bcm2835_drain_rxfifo(i2c_dev); - if (!(val & BCM2835_I2C_S_DONE)) - return IRQ_HANDLED; - } - if (val & BCM2835_I2C_S_DONE) { - if (i2c_dev->msg_buf_remaining) + if (i2c_dev->curr_msg->flags & I2C_M_RD) { + bcm2835_drain_rxfifo(i2c_dev); + val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S); + } + + if ((val & BCM2835_I2C_S_RXD) || i2c_dev->msg_buf_remaining) i2c_dev->msg_err = BCM2835_I2C_S_LEN; else i2c_dev->msg_err = 0; @@ -141,11 +141,16 @@ static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data) return IRQ_HANDLED; } - if (val & BCM2835_I2C_S_TXD) { + if (val & BCM2835_I2C_S_TXW) { bcm2835_fill_txfifo(i2c_dev); return IRQ_HANDLED; } + if (val & BCM2835_I2C_S_RXR) { + bcm2835_drain_rxfifo(i2c_dev); + return IRQ_HANDLED; + } + return IRQ_NONE; } @@ -155,6 +160,7 @@ static int bcm2835_i2c_xfer_msg(struct bcm2835_i2c_dev *i2c_dev, u32 c; unsigned long time_left; + i2c_dev->curr_msg = msg; i2c_dev->msg_buf = msg->buf; i2c_dev->msg_buf_remaining = msg->len; reinit_completion(&i2c_dev->completion);