Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757875AbaGWJs6 (ORCPT ); Wed, 23 Jul 2014 05:48:58 -0400 Received: from mail.karo-electronics.de ([81.173.242.67]:59383 "EHLO mail.karo-electronics.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756791AbaGWJs4 convert rfc822-to-8bit (ORCPT ); Wed, 23 Jul 2014 05:48:56 -0400 Date: Wed, 23 Jul 2014 11:48:34 +0200 From: Lothar =?UTF-8?B?V2HDn21hbm4=?= To: Yuan Yao Cc: , , mark.rutland@arm.com, shawn.guo@linaro.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org Subject: Re: [PATCH v5 1/2] i2c: add DMA support for freescale i2c driver Message-ID: <20140723114834.411f6bb4@ipc1.ka-ro> In-Reply-To: <1406103883-3572-2-git-send-email-yao.yuan@freescale.com> References: <1406103883-3572-1-git-send-email-yao.yuan@freescale.com> <1406103883-3572-2-git-send-email-yao.yuan@freescale.com> Organization: Ka-Ro electronics GmbH X-Mailer: Claws Mail 3.8.1 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, 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. > > Signed-off-by: Yuan Yao > --- > drivers/i2c/busses/i2c-imx.c | 377 +++++++++++++++++++++++++++++++++++++------ > 1 file changed, 324 insertions(+), 53 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c > index 1d7efa3..a9893c3 100644 > --- a/drivers/i2c/busses/i2c-imx.c > +++ b/drivers/i2c/busses/i2c-imx.c > @@ -37,22 +37,27 @@ > /** Includes ******************************************************************* > *******************************************************************************/ > > -#include > -#include > -#include > +#include > +#include > +#include > +#include > +#include > +#include > #include > #include > #include > -#include > #include > +#include > #include > -#include > -#include > -#include > -#include > +#include > +#include > #include > #include > +#include > #include > +#include > +#include > +#include > > /** Defines ******************************************************************** > *******************************************************************************/ > @@ -63,6 +68,10 @@ > /* Default value */ > #define IMX_I2C_BIT_RATE 100000 /* 100kHz */ > > +/* enable DMA if transfer byte size is bigger than this threshold */ > +#define IMX_I2C_DMA_THRESHOLD 16 > +#define IMX_I2C_DMA_TIMEOUT 1000 > + > /* IMX I2C registers: > * the I2C register offset is different between SoCs, > * to provid support for all these chips, split the > @@ -88,6 +97,7 @@ > #define I2SR_IBB 0x20 > #define I2SR_IAAS 0x40 > #define I2SR_ICF 0x80 > +#define I2CR_DMAEN 0x02 > #define I2CR_RSTA 0x04 > #define I2CR_TXAK 0x08 > #define I2CR_MTX 0x10 > @@ -174,6 +184,17 @@ struct imx_i2c_hwdata { > unsigned i2cr_ien_opcode; > }; > > +struct imx_i2c_dma { > + struct dma_chan *chan_tx; > + struct dma_chan *chan_rx; > + struct dma_chan *chan_using; > + struct completion cmd_complete; > + dma_addr_t dma_buf; > + unsigned int dma_len; > + unsigned int dma_transfer_dir; > + unsigned int dma_data_dir; > +}; > + > struct imx_i2c_struct { > struct i2c_adapter adapter; > struct clk *clk; > @@ -184,6 +205,8 @@ struct imx_i2c_struct { > int stopped; > unsigned int ifdr; /* IMX_I2C_IFDR */ > const struct imx_i2c_hwdata *hwdata; > + > + struct imx_i2c_dma *dma; > }; > > static const struct imx_i2c_hwdata imx1_i2c_hwdata = { > @@ -254,6 +277,133 @@ static inline unsigned char imx_i2c_read_reg(struct imx_i2c_struct *i2c_imx, > return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift)); > } > > +/* Functions for DMA support */ > +static int i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, > + dma_addr_t phy_addr) > +{ > + struct imx_i2c_dma *dma; > + struct dma_slave_config dma_sconfig; > + struct device *dev = &i2c_imx->adapter.dev; > + int ret; > + > + dma = devm_kzalloc(dev, sizeof(struct imx_i2c_dma), GFP_KERNEL); > + if (!dma) { > + dev_info(dev, "can't allocate DMA struct\n"); > dev_err() is designated to print ERROR messages, though this message could well be eliminated as the memory subsystem will be noisy enough if the allocation failed. > + return -ENOMEM; > + } > + > + dma->chan_tx = dma_request_slave_channel(dev, "tx"); > + > + if (!dma->chan_tx) { > + dev_info(dev, "DMA tx channel request failed\n"); > dev_err() > + ret = -ENODEV; > + goto fail_al; > + } > + > + dma_sconfig.dst_addr = phy_addr + > + (IMX_I2C_I2DR << i2c_imx->hwdata->regshift); > + dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; > + dma_sconfig.dst_maxburst = 1; > + dma_sconfig.direction = DMA_MEM_TO_DEV; > + ret = dmaengine_slave_config(dma->chan_tx, &dma_sconfig); > + if (ret < 0) { > + dev_info(dev, "DMA slave config failed, err = %d\n", ret); > dev_err() > + goto fail_tx; > + } > + > + dma->chan_rx = dma_request_slave_channel(dev, "rx"); > + if (!dma->chan_rx) { > + dev_info(dev, "DMA rx channel request failed\n"); > dev_err() > + ret = -ENODEV; > + goto fail_tx; > + } > + > + dma_sconfig.src_addr = phy_addr + > + (IMX_I2C_I2DR << i2c_imx->hwdata->regshift); > + dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; > + dma_sconfig.src_maxburst = 1; > + dma_sconfig.direction = DMA_DEV_TO_MEM; > + ret = dmaengine_slave_config(dma->chan_rx, &dma_sconfig); > + if (ret < 0) { > + dev_info(dev, "DMA slave config failed, err = %d\n", ret); > dev_err() > + goto fail_rx; > + } > + > + i2c_imx->dma = dma; > + > + init_completion(&dma->cmd_complete); > + > + return 0; > + > +fail_rx: > + dma_release_channel(dma->chan_rx); > +fail_tx: > + dma_release_channel(dma->chan_tx); > +fail_al: > + devm_kfree(dev, dma); > No need for this one (that's the whole point of using devm_kzalloc())! > + return ret; > +} > + > +static void i2c_imx_dma_callback(void *arg) > +{ > + struct imx_i2c_struct *i2c_imx = (struct imx_i2c_struct *)arg; > + struct imx_i2c_dma *dma = i2c_imx->dma; > + > + dma_unmap_single(dma->chan_using->device->dev, dma->dma_buf, > + dma->dma_len, dma->dma_data_dir); > + complete(&dma->cmd_complete); > +} > + > +static int i2c_imx_dma_xfer(struct imx_i2c_struct *i2c_imx, > + struct i2c_msg *msgs) > +{ > + struct imx_i2c_dma *dma = i2c_imx->dma; > + struct dma_async_tx_descriptor *txdesc; > + struct device *dev = &i2c_imx->adapter.dev; > + struct device *chan_dev = dma->chan_using->device->dev; > + > + dma->dma_buf = dma_map_single(chan_dev, msgs->buf, > + dma->dma_len, dma->dma_data_dir); > + if (dma_mapping_error(chan_dev, dma->dma_buf)) { > + dev_err(dev, "DMA mapping failed\n"); > + return -EINVAL; > + } > + > + txdesc = dmaengine_prep_slave_single(dma->chan_using, dma->dma_buf, > + dma->dma_len, dma->dma_transfer_dir, > + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); > + if (!txdesc) { > + dev_err(dev, "Not able to get desc for DMA xfer\n"); > s/Not able/Unable/ > + dma_unmap_single(chan_dev, dma->dma_buf, > + dma->dma_len, dma->dma_data_dir); > + return -EINVAL; > + } > + > + txdesc->callback = i2c_imx_dma_callback; > + txdesc->callback_param = i2c_imx; > + dmaengine_submit(txdesc); > + dma_async_issue_pending(dma->chan_using); > + > + return 0; > +} > + > +static void i2c_imx_dma_free(struct imx_i2c_struct *i2c_imx) > +{ > + struct imx_i2c_dma *dma = i2c_imx->dma; > + > + dma->dma_buf = 0; > + dma->dma_len = 0; > + > + dma_release_channel(dma->chan_tx); > + dma->chan_tx = NULL; > + > + dma_release_channel(dma->chan_rx); > + dma->chan_rx = NULL; > + > + dma->chan_using = NULL; > +} > + > /** Functions for IMX I2C adapter driver *************************************** > *******************************************************************************/ > > @@ -332,6 +482,11 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx) > > temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK; > imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > + > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > Why reread the register you have written just before? > + temp &= ~I2CR_DMAEN; > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > + > return result; > } > > @@ -425,44 +580,104 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id) > > static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) > { > - int i, result; > + int i, result, timeout = IMX_I2C_DMA_TIMEOUT; > + unsigned int temp = 0; > + struct imx_i2c_dma *dma = i2c_imx->dma; > + struct device *dev = &i2c_imx->adapter.dev; > > - dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n", > + dev_dbg(dev, "<%s> write slave address: addr=0x%x\n", > __func__, msgs->addr << 1); > + if (dma && msgs->len >= IMX_I2C_DMA_THRESHOLD) { > + 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; > > - /* write slave address */ > - imx_i2c_write_reg(msgs->addr << 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; > - dev_dbg(&i2c_imx->adapter.dev, "<%s> write data\n", __func__); > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > + temp |= I2CR_DMAEN; > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > > - /* write data */ > - for (i = 0; i < msgs->len; i++) { > - dev_dbg(&i2c_imx->adapter.dev, > - "<%s> write byte: B%d=0x%X\n", > - __func__, i, msgs->buf[i]); > - imx_i2c_write_reg(msgs->buf[i], i2c_imx, IMX_I2C_I2DR); > + /* > + * 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; > + } > + > + /* Waiting for Transfer complete. */ > + while (timeout--) { > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); > + if (temp & I2SR_ICF) > + break; > + udelay(10); > + } > + > + if (!timeout) > + return -ETIMEDOUT; > + 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; > + } else { > + /* write slave address */ > + imx_i2c_write_reg(msgs->addr << 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; > + > + dev_dbg(dev, "<%s> write data\n", __func__); > + > + /* write data */ > + for (i = 0; i < msgs->len; i++) { > + dev_dbg(dev, "<%s> write byte: B%d=0x%X\n", > + __func__, i, msgs->buf[i]); > + imx_i2c_write_reg(msgs->buf[i], 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; > } > > static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) > { > - int i, result; > + int i, result, timeout = IMX_I2C_DMA_TIMEOUT; > unsigned int temp; > + struct imx_i2c_dma *dma = i2c_imx->dma; > + struct device *dev = &i2c_imx->adapter.dev; > > - dev_dbg(&i2c_imx->adapter.dev, > - "<%s> write slave address: addr=0x%x\n", > + dev_dbg(dev, "<%s> write slave address: addr=0x%x\n", > __func__, (msgs->addr << 1) | 0x01); > > /* write slave address */ > @@ -474,7 +689,7 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) > if (result) > return result; > > - dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__); > + dev_dbg(dev, "<%s> setup bus\n", __func__); > > /* setup bus to read data */ > temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > @@ -484,35 +699,82 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) > imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); /* dummy read */ > > - dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__); > + dev_dbg(dev, "<%s> read data\n", __func__); > > - /* read data */ > - for (i = 0; i < msgs->len; i++) { > - result = i2c_imx_trx_complete(i2c_imx); > + if (dma && msgs->len >= IMX_I2C_DMA_THRESHOLD) { > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > + temp |= I2CR_DMAEN; > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > + > + reinit_completion(&i2c_imx->dma->cmd_complete); > + dma->chan_using = dma->chan_rx; > + dma->dma_transfer_dir = DMA_DEV_TO_MEM; > + dma->dma_data_dir = DMA_FROM_DEVICE; > + /* The last two data bytes must be transferred by the CPU. */ > + dma->dma_len = msgs->len - 2; > + result = i2c_imx_dma_xfer(i2c_imx, msgs); > if (result) > return result; > - if (i == (msgs->len - 1)) { > - /* It must generate STOP before read I2DR to prevent > - controller from generating another clock cycle */ > - dev_dbg(&i2c_imx->adapter.dev, > - "<%s> clear MSTA\n", __func__); > - temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > - temp &= ~(I2CR_MSTA | I2CR_MTX); > - imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > - i2c_imx_bus_busy(i2c_imx, 0); > - i2c_imx->stopped = 1; > - } else if (i == (msgs->len - 2)) { > - dev_dbg(&i2c_imx->adapter.dev, > - "<%s> set TXAK\n", __func__); > - temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > - temp |= I2CR_TXAK; > - imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > + > + 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; > } > - msgs->buf[i] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); > - dev_dbg(&i2c_imx->adapter.dev, > - "<%s> read byte: B%d=0x%X\n", > - __func__, i, msgs->buf[i]); > + > + /* waiting for Transfer complete. */ > + while (timeout--) { > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); > + if (temp & I2SR_ICF) > + break; > + udelay(10); > + } > + > + if (!timeout) > + return -ETIMEDOUT; > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > + temp &= ~I2CR_DMAEN; > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > + } else { > + /* read data */ > + for (i = 0; i < msgs->len - 2; i++) { > + result = i2c_imx_trx_complete(i2c_imx); > + if (result) > + return result; > + msgs->buf[i] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); > + dev_dbg(dev, "<%s> read byte: B%d=0x%X\n", > + __func__, i, msgs->buf[i]); > + } > + result = i2c_imx_trx_complete(i2c_imx); > } > + > + /* read n-1 byte data */ > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > + temp |= I2CR_TXAK; > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > + > + msgs->buf[msgs->len-2] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); > + /* read n byte data */ > + result = i2c_imx_trx_complete(i2c_imx); > + if (result) > + return result; > + > + /* > + * It must generate STOP before read I2DR to prevent > + * controller from generating another clock cycle > + */ > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > + temp &= ~(I2CR_MSTA | I2CR_MTX); > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > + i2c_imx_bus_busy(i2c_imx, 0); > + i2c_imx->stopped = 1; > + msgs->buf[msgs->len-1] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); > + > return 0; > } > > @@ -599,6 +861,7 @@ static int i2c_imx_probe(struct platform_device *pdev) > void __iomem *base; > int irq, ret; > u32 bitrate; > + u32 phy_addr; > > dev_dbg(&pdev->dev, "<%s>\n", __func__); > > @@ -609,6 +872,7 @@ static int i2c_imx_probe(struct platform_device *pdev) > } > > res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + phy_addr = res->start; > res->start is NOT a u32 type! > base = devm_ioremap_resource(&pdev->dev, res); > if (IS_ERR(base)) > return PTR_ERR(base); > @@ -694,6 +958,10 @@ static int i2c_imx_probe(struct platform_device *pdev) > i2c_imx->adapter.name); > dev_info(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n"); > > + /* Init DMA config if support*/ > + if (i2c_imx_dma_request(i2c_imx, (dma_addr_t)phy_addr)) > If you want a dma_addr_t variable, why do you declare it with a different type? Lothar Waßmann -- ___________________________________________________________ Ka-Ro electronics GmbH | Pascalstraße 22 | D - 52076 Aachen Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10 Geschäftsführer: Matthias Kaussen Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 www.karo-electronics.de | info@karo-electronics.de ___________________________________________________________ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/