From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932238AbaIEMGE (ORCPT ); Fri, 5 Sep 2014 08:06:04 -0400 Received: from mail-bl2on0134.outbound.protection.outlook.com ([65.55.169.134]:27376 "EHLO na01-bl2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756840AbaIEMGB convert rfc822-to-8bit (ORCPT ); Fri, 5 Sep 2014 08:06:01 -0400 X-Greylist: delayed 3602 seconds by postgrey-1.27 at vger.kernel.org; Fri, 05 Sep 2014 08:06:01 EDT From: Yao Yuan To: Marek Vasut CC: "wsa@the-dreams.de" , "LW@karo-electronics.de" , "mark.rutland@arm.com" , "fugang.duan@freescale.com" , "shawn.guo@linaro.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-i2c@vger.kernel.org" Subject: RE: [PATCH v7 1/2] i2c: imx: add DMA support for freescale i2c driver Thread-Topic: [PATCH v7 1/2] i2c: imx: add DMA support for freescale i2c driver Thread-Index: AQHPtuKa1yGA2bLpA0aZlDBgfnstDpvxLheAgADaxYA= Date: Fri, 5 Sep 2014 10:32:40 +0000 Message-ID: References: <1407923215-3749-1-git-send-email-yao.yuan@freescale.com> <1407923215-3749-2-git-send-email-yao.yuan@freescale.com> <201409041638.45537.marex@denx.de> In-Reply-To: <201409041638.45537.marex@denx.de> Accept-Language: en-US, zh-CN Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [123.151.195.50] x-microsoft-antispam: BCL:0;PCL:0;RULEID:;UriScan:; x-forefront-prvs: 0325F6C77B x-forefront-antispam-report: SFV:NSPM;SFS:(10019016)(6009001)(189002)(377454003)(199003)(24454002)(51704005)(81342001)(66066001)(80022001)(85852003)(76482001)(46102001)(74502001)(64706001)(20776003)(33646002)(77982001)(2656002)(79102001)(76576001)(106116001)(74316001)(87936001)(83072002)(101416001)(86362001)(90102001)(19580395003)(19580405001)(83322001)(31966008)(105586002)(107046002)(92566001)(85306004)(54356999)(108616004)(76176999)(99396002)(4396001)(50986999)(110136001)(21056001)(99286002)(95666004)(74662001)(106356001)(81542001)(24736002);DIR:OUT;SFP:1102;SCL:1;SRVR:BL2PR03MB370;H:BL2PR03MB338.namprd03.prod.outlook.com;FPR:;MLV:sfv;PTR:InfoNoRecords;MX:1;A:1;LANG:en; Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday, September 04, 2014 10:39 PM, Marek Vasut wrote: > On Wednesday, August 13, 2014 at 11:46:54 AM, Yuan Yao wrote: > > Add dma support for i2c. This function depend on DMA driver. > > You can turn on it by write both the dmas and dma-name properties in > > dts node. DMA is optional, even DMA request unsuccessfully, i2c can > > also work well. > > > > Signed-off-by: Yuan Yao > > [...] > > > +/* Enable DMA if transfer byte size is bigger than this threshold. > > + * As the hardware request, it must bigger than 4. > > The comment is unclear, just by reading it, I have no clue what are the > units for this value. I can guess those would be bytes, but it would be a > good idea to be explicit. > > Also, wasn't kernel comment style starting with leading /* , with the > text starting only on the next line ? > [Yuan Yao] Thanks for your review. I will correct it in the next version. > > + */ > > +#define IMX_I2C_DMA_THRESHOLD 16 > > +#define IMX_I2C_DMA_TIMEOUT 1000 > > + > > [...] > > > +static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx, > > + struct i2c_msg *msgs) > > +{ > > + int result; > > + unsigned int temp = 0; > > + unsigned long orig_jiffies = jiffies; > > + struct imx_i2c_dma *dma = i2c_imx->dma; > > + struct device *dev = &i2c_imx->adapter.dev; > > + > > + dev_dbg(dev, "<%s> write slave address: addr=0x%x\n", > > + __func__, msgs->addr << 1); > > + > > + reinit_completion(&i2c_imx->dma->cmd_complete); > > + dma->chan_using = dma->chan_tx; > > + dma->dma_transfer_dir = DMA_MEM_TO_DEV; > > + dma->dma_data_dir = DMA_TO_DEVICE; > > + dma->dma_len = msgs->len - 1; > > + result = i2c_imx_dma_xfer(i2c_imx, msgs); > > + if (result) > > + return result; > > + > > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > > + temp |= I2CR_DMAEN; > > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > > + > > + /* > > + * Write slave address. > > + * The first byte muse be transmitted by the CPU. > > + */ > > + imx_i2c_write_reg(msgs->addr << 1, i2c_imx, IMX_I2C_I2DR); > > + result = wait_for_completion_interruptible_timeout( > > + &i2c_imx->dma->cmd_complete, > > + msecs_to_jiffies(IMX_I2C_DMA_TIMEOUT)); > > + if (result <= 0) { > > + dmaengine_terminate_all(dma->chan_using); > > + if (result) > > + return result; > > + else > > + return -ETIMEDOUT; > > Shouldn't you force-disable the DMA here somehow (like unsetting > I2CR_DMAEN bit), if it failed or timed out? [Yuan Yao] Yes, I put the code for force-disable DMA in i2c_imx_start(). In order to make sure any DMA error will not effect the I2C. It seems almost the same as put the code here, how about your think? Thanks! > > + } > > + > > + /* Waiting for Transfer complete. */ > > + while (1) { > > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); > > + if (temp & I2SR_ICF) > > + break; > > + if (time_after(jiffies, orig_jiffies + > > + msecs_to_jiffies(IMX_I2C_DMA_TIMEOUT))) { > > + dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", > > + __func__); > > + return -ETIMEDOUT; > > + } > > + schedule(); > > + } > > + > > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > > + temp &= ~I2CR_DMAEN; > > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > > + > > + /* The last data byte must be transferred by the CPU. */ > > + imx_i2c_write_reg(msgs->buf[msgs->len-1], > > + i2c_imx, IMX_I2C_I2DR); > > + result = i2c_imx_trx_complete(i2c_imx); > > + if (result) > > + return result; > > + > > + result = i2c_imx_acked(i2c_imx); > > + if (result) > > + return result; > > + > > + return 0; > > +} > [...] > > Thanks! From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yao Yuan Subject: RE: [PATCH v7 1/2] i2c: imx: add DMA support for freescale i2c driver Date: Fri, 5 Sep 2014 10:32:40 +0000 Message-ID: References: <1407923215-3749-1-git-send-email-yao.yuan@freescale.com> <1407923215-3749-2-git-send-email-yao.yuan@freescale.com> <201409041638.45537.marex@denx.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <201409041638.45537.marex@denx.de> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Marek Vasut Cc: "mark.rutland@arm.com" , "wsa@the-dreams.de" , "linux-kernel@vger.kernel.org" , "linux-i2c@vger.kernel.org" , "fugang.duan@freescale.com" , "shawn.guo@linaro.org" , "linux-arm-kernel@lists.infradead.org" , "LW@karo-electronics.de" List-Id: linux-i2c@vger.kernel.org On Thursday, September 04, 2014 10:39 PM, Marek Vasut wrote: > On Wednesday, August 13, 2014 at 11:46:54 AM, Yuan Yao wrote: > > Add dma support for i2c. This function depend on DMA driver. > > You can turn on it by write both the dmas and dma-name properties in > > dts node. DMA is optional, even DMA request unsuccessfully, i2c can > > also work well. > > > > Signed-off-by: Yuan Yao > > [...] > > > +/* Enable DMA if transfer byte size is bigger than this threshold. > > + * As the hardware request, it must bigger than 4. > > The comment is unclear, just by reading it, I have no clue what are the > units for this value. I can guess those would be bytes, but it would be a > good idea to be explicit. > > Also, wasn't kernel comment style starting with leading /* , with the > text starting only on the next line ? > [Yuan Yao] Thanks for your review. I will correct it in the next version. > > + */ > > +#define IMX_I2C_DMA_THRESHOLD 16 > > +#define IMX_I2C_DMA_TIMEOUT 1000 > > + > > [...] > > > +static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx, > > + struct i2c_msg *msgs) > > +{ > > + int result; > > + unsigned int temp = 0; > > + unsigned long orig_jiffies = jiffies; > > + struct imx_i2c_dma *dma = i2c_imx->dma; > > + struct device *dev = &i2c_imx->adapter.dev; > > + > > + dev_dbg(dev, "<%s> write slave address: addr=0x%x\n", > > + __func__, msgs->addr << 1); > > + > > + reinit_completion(&i2c_imx->dma->cmd_complete); > > + dma->chan_using = dma->chan_tx; > > + dma->dma_transfer_dir = DMA_MEM_TO_DEV; > > + dma->dma_data_dir = DMA_TO_DEVICE; > > + dma->dma_len = msgs->len - 1; > > + result = i2c_imx_dma_xfer(i2c_imx, msgs); > > + if (result) > > + return result; > > + > > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > > + temp |= I2CR_DMAEN; > > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > > + > > + /* > > + * Write slave address. > > + * The first byte muse be transmitted by the CPU. > > + */ > > + imx_i2c_write_reg(msgs->addr << 1, i2c_imx, IMX_I2C_I2DR); > > + result = wait_for_completion_interruptible_timeout( > > + &i2c_imx->dma->cmd_complete, > > + msecs_to_jiffies(IMX_I2C_DMA_TIMEOUT)); > > + if (result <= 0) { > > + dmaengine_terminate_all(dma->chan_using); > > + if (result) > > + return result; > > + else > > + return -ETIMEDOUT; > > Shouldn't you force-disable the DMA here somehow (like unsetting > I2CR_DMAEN bit), if it failed or timed out? [Yuan Yao] Yes, I put the code for force-disable DMA in i2c_imx_start(). In order to make sure any DMA error will not effect the I2C. It seems almost the same as put the code here, how about your think? Thanks! > > + } > > + > > + /* Waiting for Transfer complete. */ > > + while (1) { > > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); > > + if (temp & I2SR_ICF) > > + break; > > + if (time_after(jiffies, orig_jiffies + > > + msecs_to_jiffies(IMX_I2C_DMA_TIMEOUT))) { > > + dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", > > + __func__); > > + return -ETIMEDOUT; > > + } > > + schedule(); > > + } > > + > > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > > + temp &= ~I2CR_DMAEN; > > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > > + > > + /* The last data byte must be transferred by the CPU. */ > > + imx_i2c_write_reg(msgs->buf[msgs->len-1], > > + i2c_imx, IMX_I2C_I2DR); > > + result = i2c_imx_trx_complete(i2c_imx); > > + if (result) > > + return result; > > + > > + result = i2c_imx_acked(i2c_imx); > > + if (result) > > + return result; > > + > > + return 0; > > +} > [...] > > Thanks! From mboxrd@z Thu Jan 1 00:00:00 1970 From: yao.yuan@freescale.com (Yao Yuan) Date: Fri, 5 Sep 2014 10:32:40 +0000 Subject: [PATCH v7 1/2] i2c: imx: add DMA support for freescale i2c driver In-Reply-To: <201409041638.45537.marex@denx.de> References: <1407923215-3749-1-git-send-email-yao.yuan@freescale.com> <1407923215-3749-2-git-send-email-yao.yuan@freescale.com> <201409041638.45537.marex@denx.de> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thursday, September 04, 2014 10:39 PM, Marek Vasut wrote: > On Wednesday, August 13, 2014 at 11:46:54 AM, Yuan Yao wrote: > > Add dma support for i2c. This function depend on DMA driver. > > You can turn on it by write both the dmas and dma-name properties in > > dts node. DMA is optional, even DMA request unsuccessfully, i2c can > > also work well. > > > > Signed-off-by: Yuan Yao > > [...] > > > +/* Enable DMA if transfer byte size is bigger than this threshold. > > + * As the hardware request, it must bigger than 4. > > The comment is unclear, just by reading it, I have no clue what are the > units for this value. I can guess those would be bytes, but it would be a > good idea to be explicit. > > Also, wasn't kernel comment style starting with leading /* , with the > text starting only on the next line ? > [Yuan Yao] Thanks for your review. I will correct it in the next version. > > + */ > > +#define IMX_I2C_DMA_THRESHOLD 16 > > +#define IMX_I2C_DMA_TIMEOUT 1000 > > + > > [...] > > > +static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx, > > + struct i2c_msg *msgs) > > +{ > > + int result; > > + unsigned int temp = 0; > > + unsigned long orig_jiffies = jiffies; > > + struct imx_i2c_dma *dma = i2c_imx->dma; > > + struct device *dev = &i2c_imx->adapter.dev; > > + > > + dev_dbg(dev, "<%s> write slave address: addr=0x%x\n", > > + __func__, msgs->addr << 1); > > + > > + reinit_completion(&i2c_imx->dma->cmd_complete); > > + dma->chan_using = dma->chan_tx; > > + dma->dma_transfer_dir = DMA_MEM_TO_DEV; > > + dma->dma_data_dir = DMA_TO_DEVICE; > > + dma->dma_len = msgs->len - 1; > > + result = i2c_imx_dma_xfer(i2c_imx, msgs); > > + if (result) > > + return result; > > + > > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > > + temp |= I2CR_DMAEN; > > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > > + > > + /* > > + * Write slave address. > > + * The first byte muse be transmitted by the CPU. > > + */ > > + imx_i2c_write_reg(msgs->addr << 1, i2c_imx, IMX_I2C_I2DR); > > + result = wait_for_completion_interruptible_timeout( > > + &i2c_imx->dma->cmd_complete, > > + msecs_to_jiffies(IMX_I2C_DMA_TIMEOUT)); > > + if (result <= 0) { > > + dmaengine_terminate_all(dma->chan_using); > > + if (result) > > + return result; > > + else > > + return -ETIMEDOUT; > > Shouldn't you force-disable the DMA here somehow (like unsetting > I2CR_DMAEN bit), if it failed or timed out? [Yuan Yao] Yes, I put the code for force-disable DMA in i2c_imx_start(). In order to make sure any DMA error will not effect the I2C. It seems almost the same as put the code here, how about your think? Thanks! > > + } > > + > > + /* Waiting for Transfer complete. */ > > + while (1) { > > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); > > + if (temp & I2SR_ICF) > > + break; > > + if (time_after(jiffies, orig_jiffies + > > + msecs_to_jiffies(IMX_I2C_DMA_TIMEOUT))) { > > + dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", > > + __func__); > > + return -ETIMEDOUT; > > + } > > + schedule(); > > + } > > + > > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > > + temp &= ~I2CR_DMAEN; > > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > > + > > + /* The last data byte must be transferred by the CPU. */ > > + imx_i2c_write_reg(msgs->buf[msgs->len-1], > > + i2c_imx, IMX_I2C_I2DR); > > + result = i2c_imx_trx_complete(i2c_imx); > > + if (result) > > + return result; > > + > > + result = i2c_imx_acked(i2c_imx); > > + if (result) > > + return result; > > + > > + return 0; > > +} > [...] > > Thanks!