From patchwork Fri Jan 14 21:08:38 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarod Wilson X-Patchwork-Id: 480481 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p0EL9QRK010906 for ; Fri, 14 Jan 2011 21:09:27 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752505Ab1ANVJZ (ORCPT ); Fri, 14 Jan 2011 16:09:25 -0500 Received: from mx1.redhat.com ([209.132.183.28]:12073 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752393Ab1ANVJZ (ORCPT ); Fri, 14 Jan 2011 16:09:25 -0500 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id p0EL8duO031321 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 14 Jan 2011 16:08:39 -0500 Received: from xavier.bos.redhat.com (xavier.bos.redhat.com [10.16.16.50]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id p0EL8cUd008440; Fri, 14 Jan 2011 16:08:38 -0500 Received: by xavier.bos.redhat.com (Postfix, from userid 500) id 77CDA81584; Fri, 14 Jan 2011 16:08:38 -0500 (EST) Date: Fri, 14 Jan 2011 16:08:38 -0500 From: Jarod Wilson To: linux-media@vger.kernel.org Cc: Andy Walls , Janne Grunau , Jean Delvare Subject: [PATCH v2] hdpvr: reduce latency of i2c read/write w/recycled buffer Message-ID: <20110114210838.GE9849@redhat.com> References: <20110114200109.GB9849@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20110114200109.GB9849@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.68 on 10.5.11.25 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Fri, 14 Jan 2011 21:09:27 +0000 (UTC) diff --git a/drivers/media/video/hdpvr/hdpvr-i2c.c b/drivers/media/video/hdpvr/hdpvr-i2c.c index c0696c3..2adfe90 100644 --- a/drivers/media/video/hdpvr/hdpvr-i2c.c +++ b/drivers/media/video/hdpvr/hdpvr-i2c.c @@ -57,23 +57,21 @@ static int hdpvr_i2c_read(struct hdpvr_device *dev, int bus, unsigned char addr, char *data, int len) { int ret; - char *buf = kmalloc(len, GFP_KERNEL); - if (!buf) - return -ENOMEM; + + if (len > sizeof(dev->i2c_buf)) + return -EINVAL; ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), REQTYPE_I2C_READ, CTRL_READ_REQUEST, - (bus << 8) | addr, 0, buf, len, 1000); + (bus << 8) | addr, 0, &dev->i2c_buf, len, 1000); if (ret == len) { - memcpy(data, buf, len); + memcpy(data, &dev->i2c_buf, len); ret = 0; } else if (ret >= 0) ret = -EIO; - kfree(buf); - return ret; } @@ -81,31 +79,29 @@ static int hdpvr_i2c_write(struct hdpvr_device *dev, int bus, unsigned char addr, char *data, int len) { int ret; - char *buf = kmalloc(len, GFP_KERNEL); - if (!buf) - return -ENOMEM; - memcpy(buf, data, len); + if (len > sizeof(dev->i2c_buf)) + return -EINVAL; + + memcpy(&dev->i2c_buf, data, len); ret = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0), REQTYPE_I2C_WRITE, CTRL_WRITE_REQUEST, - (bus << 8) | addr, 0, buf, len, 1000); + (bus << 8) | addr, 0, &dev->i2c_buf, len, 1000); if (ret < 0) - goto error; + return ret; ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), REQTYPE_I2C_WRITE_STATT, CTRL_READ_REQUEST, - 0, 0, buf, 2, 1000); + 0, 0, &dev->i2c_buf, 2, 1000); - if ((ret == 2) && (buf[1] == (len - 1))) + if ((ret == 2) && (dev->i2c_buf[1] == (len - 1))) ret = 0; else if (ret >= 0) ret = -EIO; -error: - kfree(buf); return ret; } diff --git a/drivers/media/video/hdpvr/hdpvr.h b/drivers/media/video/hdpvr/hdpvr.h index 29f7426..ee74e3b 100644 --- a/drivers/media/video/hdpvr/hdpvr.h +++ b/drivers/media/video/hdpvr/hdpvr.h @@ -25,6 +25,7 @@ KERNEL_VERSION(HDPVR_MAJOR_VERSION, HDPVR_MINOR_VERSION, HDPVR_RELEASE) #define HDPVR_MAX 8 +#define HDPVR_I2C_MAX_SIZE 128 /* Define these values to match your devices */ #define HD_PVR_VENDOR_ID 0x2040 @@ -109,6 +110,8 @@ struct hdpvr_device { struct i2c_adapter i2c_adapter; /* I2C lock */ struct mutex i2c_mutex; + /* I2C message buffer space */ + char i2c_buf[HDPVR_I2C_MAX_SIZE]; /* For passing data to ir-kbd-i2c */ struct IR_i2c_init_data ir_i2c_init_data;