From patchwork Thu Aug 16 14:03:47 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shubhrajyoti Datta X-Patchwork-Id: 1332501 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 4DFD840210 for ; Thu, 16 Aug 2012 14:05:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964778Ab2HPOFZ (ORCPT ); Thu, 16 Aug 2012 10:05:25 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:36409 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757333Ab2HPOFQ (ORCPT ); Thu, 16 Aug 2012 10:05:16 -0400 Received: from dbdp20.itg.ti.com ([172.24.170.38]) by bear.ext.ti.com (8.13.7/8.13.7) with ESMTP id q7GE49BF031072; Thu, 16 Aug 2012 09:04:10 -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 q7GE47j2025884; Thu, 16 Aug 2012 19:34:09 +0530 (IST) Received: from dbdp32.itg.ti.com (172.24.170.251) by dbde70.ent.ti.com (172.24.170.148) with Microsoft SMTP Server id 14.1.323.3; Thu, 16 Aug 2012 19:34:08 +0530 Received: from ula0393217.india.ti.com (smtpvbd.itg.ti.com [172.24.170.250]) by dbdp32.itg.ti.com (8.13.8/8.13.8) with ESMTP id q7GE44Kt027608; Thu, 16 Aug 2012 19:34:08 +0530 From: Shubhrajyoti D To: CC: , , , , , Felipe Balbi , Shubhrajyoti D Subject: [PATCHv7 16/24] i2c: omap: resize fifos before each message Date: Thu, 16 Aug 2012 19:33:47 +0530 Message-ID: <1345125835-15524-17-git-send-email-shubhrajyoti@ti.com> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1345125835-15524-1-git-send-email-shubhrajyoti@ti.com> References: <1345125835-15524-1-git-send-email-shubhrajyoti@ti.com> MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.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);