From patchwork Wed Dec 3 12:35:24 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Harini Katakam X-Patchwork-Id: 5430391 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 26C72BEEA8 for ; Wed, 3 Dec 2014 12:38:29 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 06AE8202B8 for ; Wed, 3 Dec 2014 12:38:28 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DAD9020265 for ; Wed, 3 Dec 2014 12:38:26 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Xw9AM-00017y-7d; Wed, 03 Dec 2014 12:36:22 +0000 Received: from mail-qa0-x236.google.com ([2607:f8b0:400d:c00::236]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Xw9AH-0000yJ-HN for linux-arm-kernel@lists.infradead.org; Wed, 03 Dec 2014 12:36:18 +0000 Received: by mail-qa0-f54.google.com with SMTP id i13so10112732qae.41 for ; Wed, 03 Dec 2014 04:35:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=3Mutn8nKy6rQ4iljfYS9XDeHJkjFLKcpTz9y5fPyFFE=; b=x5z1wxF+E5iaHCqcTzZ+ghRhxjoXjklY7BxUzTLF0npcq4XoTJ8FabQHjup5nQIJbQ WVgV0SULJrTN43Xbr+fhsoraq3d7dSNMmLDOHCt3IfkPyEE+uoHJAiOaKA9grbewUi6k OpCZBrXqQlYrqSp59/oZFjsB22ux5oG8oZNszR5X/4olXkR8n0av46ZcjWNpfIprKCIM VR15tv4qR7OYfRxjhlYBjFVNaJxct93hTJw0XiVBMwcZrjBXA1ZBZaBFVfO4w5AT/Nrb yfqXyrSpKGW0p54f/So+q0J4Zgy/VOQDJvynPvzAqkw9Z1Tg6TZoQaD6B4vbpQHBgOXF jqvQ== X-Received: by 10.224.67.7 with SMTP id p7mr7532251qai.97.1417610156242; Wed, 03 Dec 2014 04:35:56 -0800 (PST) Received: from localhost ([149.199.62.254]) by mx.google.com with ESMTPSA id t5sm17662732qad.5.2014.12.03.04.35.54 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Wed, 03 Dec 2014 04:35:55 -0800 (PST) From: Harini Katakam To: wsa@the-dreams.de, mark.rutland@arm.com Subject: [PATCH v2 1/3] i2c: cadence: Handle > 252 byte transfers Date: Wed, 3 Dec 2014 18:05:24 +0530 Message-Id: <1417610126-7957-2-git-send-email-harinik@xilinx.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1417610126-7957-1-git-send-email-harinik@xilinx.com> References: <1417610126-7957-1-git-send-email-harinik@xilinx.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141203_043617_763198_66F46954 X-CRM114-Status: GOOD ( 23.73 ) X-Spam-Score: -0.7 (/) Cc: harinik@xilinx.com, vishnum@xilinx.com, linux-kernel@vger.kernel.org, harinikatakamlinux@gmail.com, michal.simek@xilinx.com, soren.brinkmann@xilinx.com, linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_LOW, T_DKIM_INVALID, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The I2C controller sends a NACK to the slave when transfer size register reaches zero, irrespective of the hold bit. So, in order to handle transfers greater than 252 bytes, the transfer size register has to be maintained at a value >= 1. This patch implements the same. The interrupt status is cleared at the beginning of the isr instead of the end, to avoid missing any interrupts - this is in sync with the new transfer handling. Signed-off-by: Harini Katakam --- v2: No changes --- drivers/i2c/busses/i2c-cadence.c | 156 ++++++++++++++++++++------------------ 1 file changed, 81 insertions(+), 75 deletions(-) diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c index 63f3f03..e54899e 100644 --- a/drivers/i2c/busses/i2c-cadence.c +++ b/drivers/i2c/busses/i2c-cadence.c @@ -126,6 +126,7 @@ * @suspended: Flag holding the device's PM status * @send_count: Number of bytes still expected to send * @recv_count: Number of bytes still expected to receive + * @curr_recv_count: Number of bytes to be received in current transfer * @irq: IRQ number * @input_clk: Input clock to I2C controller * @i2c_clk: Maximum I2C clock speed @@ -144,6 +145,7 @@ struct cdns_i2c { u8 suspended; unsigned int send_count; unsigned int recv_count; + unsigned int curr_recv_count; int irq; unsigned long input_clk; unsigned int i2c_clk; @@ -180,14 +182,15 @@ static void cdns_i2c_clear_bus_hold(struct cdns_i2c *id) */ static irqreturn_t cdns_i2c_isr(int irq, void *ptr) { - unsigned int isr_status, avail_bytes; - unsigned int bytes_to_recv, bytes_to_send; + unsigned int isr_status, avail_bytes, updatetx; + unsigned int bytes_to_send; struct cdns_i2c *id = ptr; /* Signal completion only after everything is updated */ int done_flag = 0; irqreturn_t status = IRQ_NONE; isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); + cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); /* Handling nack and arbitration lost interrupt */ if (isr_status & (CDNS_I2C_IXR_NACK | CDNS_I2C_IXR_ARB_LOST)) { @@ -195,89 +198,91 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr) status = IRQ_HANDLED; } - /* Handling Data interrupt */ - if ((isr_status & CDNS_I2C_IXR_DATA) && - (id->recv_count >= CDNS_I2C_DATA_INTR_DEPTH)) { - /* Always read data interrupt threshold bytes */ - bytes_to_recv = CDNS_I2C_DATA_INTR_DEPTH; - id->recv_count -= CDNS_I2C_DATA_INTR_DEPTH; - avail_bytes = cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); - - /* - * if the tranfer size register value is zero, then - * check for the remaining bytes and update the - * transfer size register. - */ - if (!avail_bytes) { - if (id->recv_count > CDNS_I2C_TRANSFER_SIZE) - cdns_i2c_writereg(CDNS_I2C_TRANSFER_SIZE, - CDNS_I2C_XFER_SIZE_OFFSET); - else - cdns_i2c_writereg(id->recv_count, - CDNS_I2C_XFER_SIZE_OFFSET); - } + updatetx = 0; + if (id->recv_count > id->curr_recv_count) + updatetx = 1; + + /* When receiving, handle data and transfer complete interrupts */ + if (id->p_recv_buf && + ((isr_status & CDNS_I2C_IXR_COMP) || + (isr_status & CDNS_I2C_IXR_DATA))) { + while (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) & + CDNS_I2C_SR_RXDV) { + if ((id->recv_count < CDNS_I2C_FIFO_DEPTH) && + !id->bus_hold_flag) + cdns_i2c_clear_bus_hold(id); - /* Process the data received */ - while (bytes_to_recv--) *(id->p_recv_buf)++ = cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET); + id->recv_count--; + id->curr_recv_count--; - if (!id->bus_hold_flag && - (id->recv_count <= CDNS_I2C_FIFO_DEPTH)) - cdns_i2c_clear_bus_hold(id); + if (updatetx && + (id->curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1)) + break; + } - status = IRQ_HANDLED; - } + if (updatetx && + (id->curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1)) { + /* wait while fifo is full */ + while (cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET) != + (id->curr_recv_count - CDNS_I2C_FIFO_DEPTH)) + ; - /* Handling Transfer Complete interrupt */ - if (isr_status & CDNS_I2C_IXR_COMP) { - if (!id->p_recv_buf) { - /* - * If the device is sending data If there is further - * data to be sent. Calculate the available space - * in FIFO and fill the FIFO with that many bytes. - */ - if (id->send_count) { - avail_bytes = CDNS_I2C_FIFO_DEPTH - - cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); - if (id->send_count > avail_bytes) - bytes_to_send = avail_bytes; - else - bytes_to_send = id->send_count; - - while (bytes_to_send--) { - cdns_i2c_writereg( - (*(id->p_send_buf)++), - CDNS_I2C_DATA_OFFSET); - id->send_count--; - } + if (((int)(id->recv_count) - CDNS_I2C_FIFO_DEPTH) > + CDNS_I2C_TRANSFER_SIZE) { + cdns_i2c_writereg(CDNS_I2C_TRANSFER_SIZE, + CDNS_I2C_XFER_SIZE_OFFSET); + id->curr_recv_count = CDNS_I2C_TRANSFER_SIZE + + CDNS_I2C_FIFO_DEPTH; } else { - /* - * Signal the completion of transaction and - * clear the hold bus bit if there are no - * further messages to be processed. - */ - done_flag = 1; + cdns_i2c_writereg(id->recv_count - + CDNS_I2C_FIFO_DEPTH, + CDNS_I2C_XFER_SIZE_OFFSET); + id->curr_recv_count = id->recv_count; } - if (!id->send_count && !id->bus_hold_flag) - cdns_i2c_clear_bus_hold(id); - } else { + } + + if ((isr_status & CDNS_I2C_IXR_COMP) && !id->recv_count) { if (!id->bus_hold_flag) cdns_i2c_clear_bus_hold(id); + done_flag = 1; + } + + status = IRQ_HANDLED; + } + + /* When sending, handle transfer complete interrupt */ + if ((isr_status & CDNS_I2C_IXR_COMP) && !id->p_recv_buf) { + /* + * If the device is sending data If there is further + * data to be sent. Calculate the available space + * in FIFO and fill the FIFO with that many bytes. + */ + if (id->send_count) { + avail_bytes = CDNS_I2C_FIFO_DEPTH - + cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); + if (id->send_count > avail_bytes) + bytes_to_send = avail_bytes; + else + bytes_to_send = id->send_count; + + while (bytes_to_send--) { + cdns_i2c_writereg( + (*(id->p_send_buf)++), + CDNS_I2C_DATA_OFFSET); + id->send_count--; + } + } else { /* - * If the device is receiving data, then signal - * the completion of transaction and read the data - * present in the FIFO. Signal the completion of - * transaction. + * Signal the completion of transaction and + * clear the hold bus bit if there are no + * further messages to be processed. */ - while (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) & - CDNS_I2C_SR_RXDV) { - *(id->p_recv_buf)++ = - cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET); - id->recv_count--; - } done_flag = 1; } + if (!id->send_count && !id->bus_hold_flag) + cdns_i2c_clear_bus_hold(id); status = IRQ_HANDLED; } @@ -287,8 +292,6 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr) if (id->err_status) status = IRQ_HANDLED; - cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); - if (done_flag) complete(&id->xfer_done); @@ -314,6 +317,8 @@ static void cdns_i2c_mrecv(struct cdns_i2c *id) if (id->p_msg->flags & I2C_M_RECV_LEN) id->recv_count = I2C_SMBUS_BLOCK_MAX + 1; + id->curr_recv_count = id->recv_count; + /* * Check for the message size against FIFO depth and set the * 'hold bus' bit if it is greater than FIFO depth. @@ -333,10 +338,11 @@ static void cdns_i2c_mrecv(struct cdns_i2c *id) * receive if it is less than transfer size and transfer size if * it is more. Enable the interrupts. */ - if (id->recv_count > CDNS_I2C_TRANSFER_SIZE) + if (id->recv_count > CDNS_I2C_TRANSFER_SIZE) { cdns_i2c_writereg(CDNS_I2C_TRANSFER_SIZE, CDNS_I2C_XFER_SIZE_OFFSET); - else + id->curr_recv_count = CDNS_I2C_TRANSFER_SIZE; + } else cdns_i2c_writereg(id->recv_count, CDNS_I2C_XFER_SIZE_OFFSET); /* Clear the bus hold flag if bytes to receive is less than FIFO size */ if (!id->bus_hold_flag &&