From patchwork Tue Aug 14 14:18:58 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shubhrajyoti Datta X-Patchwork-Id: 1320461 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork2.kernel.org (Postfix) with ESMTP id 4A605DF215 for ; Tue, 14 Aug 2012 14:30:19 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1T1I3c-0005xA-I2; Tue, 14 Aug 2012 14:25:21 +0000 Received: from bear.ext.ti.com ([192.94.94.41]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1T1HyP-0003GC-8U for linux-arm-kernel@lists.infradead.org; Tue, 14 Aug 2012 14:20:00 +0000 Received: from dbdp20.itg.ti.com ([172.24.170.38]) by bear.ext.ti.com (8.13.7/8.13.7) with ESMTP id q7EEJP7r024487; Tue, 14 Aug 2012 09:19:26 -0500 Received: from DBDE70.ent.ti.com (localhost [127.0.0.1]) by dbdp20.itg.ti.com (8.13.8/8.13.8) with ESMTP id q7EEJMtH026377; Tue, 14 Aug 2012 19:49:24 +0530 (IST) Received: from dbdp33.itg.ti.com (172.24.170.252) by dbde70.ent.ti.com (172.24.170.148) with Microsoft SMTP Server id 14.1.323.3; Tue, 14 Aug 2012 19:49:23 +0530 Received: from ula0393217.india.ti.com (smtpvbd.itg.ti.com [172.24.170.250]) by dbdp33.itg.ti.com (8.13.8/8.13.8) with ESMTP id q7EEJGmM011366; Tue, 14 Aug 2012 19:49:23 +0530 From: Shubhrajyoti D To: Subject: [PATCHv6 16/24] i2c: omap: resize fifos before each message Date: Tue, 14 Aug 2012 19:48:58 +0530 Message-ID: <1344953946-13005-17-git-send-email-shubhrajyoti@ti.com> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1344953946-13005-1-git-send-email-shubhrajyoti@ti.com> References: <1344953946-13005-1-git-send-email-shubhrajyoti@ti.com> MIME-Version: 1.0 X-Spam-Note: CRM114 invocation failed X-Spam-Score: -6.9 (------) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-6.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at http://www.dnswl.org/, high trust [192.94.94.41 listed in list.dnswl.org] -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: tony@atomide.com, w.sang@pengutronix.de, Felipe Balbi , linux-i2c@vger.kernel.org, ben-linux@fluff.org, Shubhrajyoti D , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org From: Felipe Balbi This patch will try to avoid the usage of draining feature by reconfiguring the FIFO the start condition of each message based on the message's size. By doing that, we will be better utilizing the FIFO when doing big transfers. While at that also drop the now unneeded check for dev->buf_len as we always know the amount of data to be transmitted. Signed-off-by: Felipe Balbi Signed-off-by: Shubhrajyoti D --- drivers/i2c/busses/i2c-omap.c | 83 +++++++++++++++++++++++++---------------- 1 files changed, 51 insertions(+), 32 deletions(-) diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c index b0b1705..dfbf667 100644 --- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c @@ -193,6 +193,7 @@ struct omap_i2c_dev { u8 *regs; size_t buf_len; struct i2c_adapter adapter; + u8 threshold; u8 fifo_size; /* use as flag and value * fifo_size==0 implies no fifo * if set, should be trsh+1 @@ -418,13 +419,6 @@ static int omap_i2c_init(struct omap_i2c_dev *dev) omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, scll); omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, sclh); - if (dev->fifo_size) { - /* Note: setup required fifo size - 1. RTRSH and XTRSH */ - buf = (dev->fifo_size - 1) << 8 | OMAP_I2C_BUF_RXFIF_CLR | - (dev->fifo_size - 1) | OMAP_I2C_BUF_TXFIF_CLR; - omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, buf); - } - /* Take the I2C module out of reset: */ omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN); @@ -462,6 +456,45 @@ static int omap_i2c_wait_for_bb(struct omap_i2c_dev *dev) return 0; } +static void omap_i2c_resize_fifo(struct omap_i2c_dev *dev, u8 size, bool is_rx) +{ + u16 buf; + + if (dev->flags & OMAP_I2C_FLAG_NO_FIFO) + return; + + /* + * Set up notification threshold based on message size. We're doing + * this to try and avoid draining feature as much as possible. Whenever + * we have big messages to transfer (bigger than our total fifo size) + * then we might use draining feature to transfer the remaining bytes. + */ + + dev->threshold = clamp(size, (u8) 1, dev->fifo_size); + + buf = omap_i2c_read_reg(dev, OMAP_I2C_BUF_REG); + + if (is_rx) { + /* Clear RX Threshold */ + buf &= ~(0x3f << 8); + buf |= ((dev->threshold - 1) << 8) | OMAP_I2C_BUF_RXFIF_CLR; + } else { + /* Clear TX Threshold */ + buf &= ~0x3f; + buf |= (dev->threshold - 1) | OMAP_I2C_BUF_TXFIF_CLR; + } + + omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, buf); + + if (dev->rev < OMAP_I2C_REV_ON_3630_4430) + dev->b_hw = 1; /* Enable hardware fixes */ + + /* calculate wakeup latency constraint for MPU */ + if (dev->set_mpu_wkup_lat != NULL) + dev->latency = (1000000 * dev->threshold) / + (1000 * dev->speed / 8); +} + /* * Low level master read/write transaction. */ @@ -478,6 +511,9 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap, if (msg->len == 0) return -EINVAL; + dev->receiver = !!(msg->flags & I2C_M_RD); + omap_i2c_resize_fifo(dev, msg->len, dev->receiver); + omap_i2c_write_reg(dev, OMAP_I2C_SA_REG, msg->addr); /* REVISIT: Could the STB bit of I2C_CON be used with probing? */ @@ -493,7 +529,6 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap, INIT_COMPLETION(dev->cmd_complete); dev->cmd_err = 0; - dev->receiver = !!(msg->flags & I2C_M_RD); w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT; @@ -760,12 +795,6 @@ static void omap_i2c_receive_data(struct omap_i2c_dev *dev, u8 num_bytes, u16 w; while (num_bytes--) { - if (!dev->buf_len) { - dev_err(dev->dev, "%s without data", - is_rdr ? "RDR" : "RRDY"); - break; - } - w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG); *dev->buf++ = w; dev->buf_len--; @@ -775,10 +804,8 @@ static void omap_i2c_receive_data(struct omap_i2c_dev *dev, u8 num_bytes, * omap4 is 8 bit wide */ if (dev->flags & OMAP_I2C_FLAG_16BIT_DATA_REG) { - if (dev->buf_len) { - *dev->buf++ = w >> 8; - dev->buf_len--; - } + *dev->buf++ = w >> 8; + dev->buf_len--; } } } @@ -789,12 +816,6 @@ static int omap_i2c_transmit_data(struct omap_i2c_dev *dev, u8 num_bytes, u16 w; while (num_bytes--) { - if (!dev->buf_len) { - dev_err(dev->dev, "%s without data", - is_xdr ? "XDR" : "XRDY"); - break; - } - w = *dev->buf++; dev->buf_len--; @@ -803,10 +824,8 @@ static int omap_i2c_transmit_data(struct omap_i2c_dev *dev, u8 num_bytes, * omap4 is 8 bit wide */ if (dev->flags & OMAP_I2C_FLAG_16BIT_DATA_REG) { - if (dev->buf_len) { - w |= *dev->buf++ << 8; - dev->buf_len--; - } + w |= *dev->buf++ << 8; + dev->buf_len--; } if (dev->errata & I2C_OMAP_ERRATA_I462) { @@ -901,8 +920,8 @@ complete: if (stat & OMAP_I2C_STAT_RRDY) { u8 num_bytes = 1; - if (dev->fifo_size) - num_bytes = dev->fifo_size; + if (dev->threshold) + num_bytes = dev->threshold; omap_i2c_receive_data(dev, num_bytes, false); omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RRDY); @@ -929,8 +948,8 @@ complete: u8 num_bytes = 1; int ret; - if (dev->fifo_size) - num_bytes = dev->fifo_size; + if (dev->threshold) + num_bytes = dev->threshold; ret = omap_i2c_transmit_data(dev, num_bytes, false); stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);