| Message ID | 1394675277-24913-2-git-send-email-yao.yuan@freescale.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thursday, March 13, 2014 at 02:47:56 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. > > Signed-off-by: Yuan Yao <yao.yuan@freescale.com> > --- > drivers/i2c/busses/i2c-imx.c | 354 > +++++++++++++++++++++++++++++++++++++------ 1 file changed, 306 > insertions(+), 48 deletions(-) Changelog is missing. [...] > +/* 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 = i2c_imx->dma; > + struct dma_slave_config dma_sconfig; > + struct device *dev = &i2c_imx->adapter.dev; > + int ret; > + > + dma->chan_tx = dma_request_slave_channel(dev, "tx"); > + if (!dma->chan_tx) { > + dev_err(dev, "Dma tx channel request failed!\n"); DMA is written in all caps, it's an abbrev. for Direct Memory Access . Please fix globally. [...] > static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg > *msgs) { [...] > - /* 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); > + 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 */ > + 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); > + } Do you ever check if this really timed out and handle such case at all ? I don't see it , but I might be wrong ... > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > + temp &= ~I2CR_DMAEN; > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > + > + /* write the last byte */ > + 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(&i2c_imx->adapter.dev, "<%s> write data\n", __func__); > + > + /* 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]); Can you not just have a variable $dev here and avoid having such a long noodle in the dev_dbg() call ? > + 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; > } [...] > + /* waiting for Transfer complete. */ > + while (timeout--) { > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); > + if (temp & I2SR_ICF) > + break; > + udelay(10); > + } Timeout handling here as well ... [...] > @@ -696,6 +936,21 @@ 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*/ > + i2c_imx->dma = devm_kzalloc(&pdev->dev, sizeof(struct imx_i2c_dma), > + GFP_KERNEL); > + if (!i2c_imx->dma) { > + dev_info(&pdev->dev, > + "can't allocate dma struct faild use dma.\n"); Or just have $dev variable and you won't have to break the line at all ... > + i2c_imx->use_dma = false; > + } else if (i2c_imx_dma_request(i2c_imx, (dma_addr_t)phy_addr)) { > + dev_info(&pdev->dev, > + "can't request dma chan, faild use dma.\n"); > + i2c_imx->use_dma = false; > + } else { > + i2c_imx->use_dma = true; > + } Can you not just check if i2c_imx->dma is valid pointer or NULL pointer ? Then you won't need a separate variable, for this purpose ... right ? [...]
On Sunday, March 23, 2014 @ 11:50:00 AM, Marek Vasut wrote: > On Thursday, March 13, 2014 at 02:47:56 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. > > > > Signed-off-by: Yuan Yao <yao.yuan@freescale.com> > > --- > > drivers/i2c/busses/i2c-imx.c | 354 > > +++++++++++++++++++++++++++++++++++++------ 1 file changed, 306 > > insertions(+), 48 deletions(-) > > Changelog is missing. Sorry for this, Maybe the changelog is in the junk box. It's named "[PATCH v3 0/2] i2c: add DMA support for freescale i2c driver". > [...] > > > +/* 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 = i2c_imx->dma; > > + struct dma_slave_config dma_sconfig; > > + struct device *dev = &i2c_imx->adapter.dev; > > + int ret; > > + > > + dma->chan_tx = dma_request_slave_channel(dev, "tx"); > > + if (!dma->chan_tx) { > > + dev_err(dev, "Dma tx channel request failed!\n"); > > DMA is written in all caps, it's an abbrev. for Direct Memory Access . > Please fix globally. > Ok, I will fix it globally. > [...] > > > static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct > > i2c_msg > > *msgs) { > > [...] > > > - /* 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); > > + 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 */ > > + 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); > > + } > > Do you ever check if this really timed out and handle such case at all ? > I don't see it , but I might be wrong ... > Oh, It's a bug, Thank you very much. > > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > > + temp &= ~I2CR_DMAEN; > > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > > + > > + /* write the last byte */ > > + 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(&i2c_imx->adapter.dev, "<%s> write data\n", __func__); > > + > > + /* 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]); > > Can you not just have a variable $dev here and avoid having such a long > noodle in the dev_dbg() call ? > Ok, And I don't think the dev_dbg() is very helpful here now. > > + 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; > > } > [...] > > > + /* waiting for Transfer complete. */ > > + while (timeout--) { > > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); > > + if (temp & I2SR_ICF) > > + break; > > + udelay(10); > > + } > > Timeout handling here as well ... > > [...] > > > @@ -696,6 +936,21 @@ 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*/ > > + i2c_imx->dma = devm_kzalloc(&pdev->dev, sizeof(struct imx_i2c_dma), > > + GFP_KERNEL); > > + if (!i2c_imx->dma) { > > + dev_info(&pdev->dev, > > + "can't allocate dma struct faild use dma.\n"); > > Or just have $dev variable and you won't have to break the line at all ... > > > + i2c_imx->use_dma = false; > > + } else if (i2c_imx_dma_request(i2c_imx, (dma_addr_t)phy_addr)) { > > + dev_info(&pdev->dev, > > + "can't request dma chan, faild use dma.\n"); > > + i2c_imx->use_dma = false; > > + } else { > > + i2c_imx->use_dma = true; > > + } > > Can you not just check if i2c_imx->dma is valid pointer or NULL pointer ? > Then you won't need a separate variable, for this purpose ... right ? Sorry and I think what I know is just to check whether it is NULL. Then for the second question, maybe there are some other ways, But I think it is more tidy and easier understanding for using a separate variable, for this purpose. > [...] > Best regards, Yuan Yao
On Wednesday, March 26, 2014 at 04:08:27 AM, Yao Yuan wrote: [...] > > > + i2c_imx->use_dma = false; > > > + } else if (i2c_imx_dma_request(i2c_imx, (dma_addr_t)phy_addr)) { > > > + dev_info(&pdev->dev, > > > + "can't request dma chan, faild use dma.\n"); > > > + i2c_imx->use_dma = false; > > > + } else { > > > + i2c_imx->use_dma = true; > > > + } > > > > Can you not just check if i2c_imx->dma is valid pointer or NULL pointer ? > > Then you won't need a separate variable, for this purpose ... right ? > > Sorry and I think what I know is just to check whether it is NULL. > Then for the second question, maybe there are some other ways, But I think > it is more tidy and easier understanding for using a separate variable, > for this purpose. You are just wasting space and duplicating data, unless I am wrong. Best regards, Marek Vasut
On Wednesday, March 26, 2014 at 11:43:27 AM, Marek Vasut wrote: > On Wednesday, March 26, 2014 at 04:08:27 AM, Yao Yuan wrote: > > [...] > > > > > + i2c_imx->use_dma = false; > > > > + } else if (i2c_imx_dma_request(i2c_imx, (dma_addr_t)phy_addr)) > { > > > > + dev_info(&pdev->dev, > > > > + "can't request dma chan, faild use dma.\n"); > > > > + i2c_imx->use_dma = false; > > > > + } else { > > > > + i2c_imx->use_dma = true; > > > > + } > > > > > > Can you not just check if i2c_imx->dma is valid pointer or NULL > pointer ? > > > Then you won't need a separate variable, for this purpose ... right ? > > > > Sorry and I think what I know is just to check whether it is NULL. > > Then for the second question, maybe there are some other ways, But I > > think it is more tidy and easier understanding for using a separate > > variable, for this purpose. > > You are just wasting space and duplicating data, unless I am wrong. > Well, Do you have a better idea? Although I think it's necessary. Best regards, Yuan Yao
On Wednesday, March 26, 2014 at 06:56:34 AM, Yao Yuan wrote: > On Wednesday, March 26, 2014 at 11:43:27 AM, Marek Vasut wrote: > > On Wednesday, March 26, 2014 at 04:08:27 AM, Yao Yuan wrote: > > > > [...] > > > > > > > + i2c_imx->use_dma = false; > > > > > + } else if (i2c_imx_dma_request(i2c_imx, (dma_addr_t)phy_addr)) > > > > { > > > > > > > + dev_info(&pdev->dev, > > > > > + "can't request dma chan, faild use dma. \n"); > > > > > + i2c_imx->use_dma = false; > > > > > + } else { > > > > > + i2c_imx->use_dma = true; > > > > > + } > > > > > > > > Can you not just check if i2c_imx->dma is valid pointer or NULL > > > > pointer ? > > > > > > Then you won't need a separate variable, for this purpose ... right ? > > > > > > Sorry and I think what I know is just to check whether it is NULL. > > > Then for the second question, maybe there are some other ways, But I > > > think it is more tidy and easier understanding for using a separate > > > variable, for this purpose. > > > > You are just wasting space and duplicating data, unless I am wrong. > > Well, Do you have a better idea? Although I think it's necessary. I think we disconnected here, sorry. Why can you not use (i2c_imx->dma != NULL) instead of (i2c_imx->use_dma == true) please ? Best regards, Marek Vasut
On Wednesday, March 26, 2014 at 02:27:46 PM, Marek Vasut wrote: > On Wednesday, March 26, 2014 at 06:56:34 AM, Yao Yuan wrote: > > On Wednesday, March 26, 2014 at 11:43:27 AM, Marek Vasut wrote: > > > On Wednesday, March 26, 2014 at 04:08:27 AM, Yao Yuan wrote: > > > > > > [...] > > > > > > > > > + i2c_imx->use_dma = false; > > > > > > + } else if (i2c_imx_dma_request(i2c_imx, > > > > > > +(dma_addr_t)phy_addr)) > > > > > > { > > > > > > > > > + dev_info(&pdev->dev, > > > > > > + "can't request dma chan, faild use dma. > \n"); > > > > > > + i2c_imx->use_dma = false; > > > > > > + } else { > > > > > > + i2c_imx->use_dma = true; > > > > > > + } > > > > > > > > > > Can you not just check if i2c_imx->dma is valid pointer or NULL > > > > > > pointer ? > > > > > > > > Then you won't need a separate variable, for this purpose ... > right ? > > > > > > > > Sorry and I think what I know is just to check whether it is NULL. > > > > Then for the second question, maybe there are some other ways, But > > > > I think it is more tidy and easier understanding for using a > > > > separate variable, for this purpose. > > > > > > You are just wasting space and duplicating data, unless I am wrong. > > > > Well, Do you have a better idea? Although I think it's necessary. > > I think we disconnected here, sorry. Why can you not use (i2c_imx->dma != > NULL) instead of (i2c_imx->use_dma == true) please ? > But there are two judge conditions. But only the "i2c_imx->dma", but also whether "i2c_imx_dma_request" success. "i2c_imx->use_dma == true" be equivalent to "i2c_imx->dma != NULL && !i2c_imx_dma_request()"
On Wednesday, March 26, 2014 at 08:08:28 AM, Yao Yuan wrote: > On Wednesday, March 26, 2014 at 02:27:46 PM, Marek Vasut wrote: > > On Wednesday, March 26, 2014 at 06:56:34 AM, Yao Yuan wrote: > > > On Wednesday, March 26, 2014 at 11:43:27 AM, Marek Vasut wrote: > > > > On Wednesday, March 26, 2014 at 04:08:27 AM, Yao Yuan wrote: > > > > > > > > [...] > > > > > > > > > > > + i2c_imx->use_dma = false; > > > > > > > + } else if (i2c_imx_dma_request(i2c_imx, > > > > > > > +(dma_addr_t)phy_addr)) > > > > > > > > { > > > > > > > > > > > + dev_info(&pdev->dev, > > > > > > > + "can't request dma chan, faild use dma. > > > > \n"); > > > > > > > > > + i2c_imx->use_dma = false; > > > > > > > + } else { > > > > > > > + i2c_imx->use_dma = true; > > > > > > > + } > > > > > > > > > > > > Can you not just check if i2c_imx->dma is valid pointer or NULL > > > > > > > > pointer ? > > > > > > > > > > Then you won't need a separate variable, for this purpose ... > > > > right ? > > > > > > > Sorry and I think what I know is just to check whether it is NULL. > > > > > Then for the second question, maybe there are some other ways, But > > > > > I think it is more tidy and easier understanding for using a > > > > > separate variable, for this purpose. > > > > > > > > You are just wasting space and duplicating data, unless I am wrong. > > > > > > Well, Do you have a better idea? Although I think it's necessary. > > > > I think we disconnected here, sorry. Why can you not use (i2c_imx->dma != > > NULL) instead of (i2c_imx->use_dma == true) please ? > > But there are two judge conditions. But only the "i2c_imx->dma", but also > whether "i2c_imx_dma_request" success. > > "i2c_imx->use_dma == true" be equivalent to "i2c_imx->dma != NULL && > !i2c_imx_dma_request()" + /* Init DMA config if support*/ + i2c_imx->dma = devm_kzalloc(&pdev->dev, sizeof(struct imx_i2c_dma), + GFP_KERNEL); + if (!i2c_imx->dma) { + dev_info(&pdev->dev, + "can't allocate dma struct faild use dma.\n"); + i2c_imx->use_dma = false; + } else if (i2c_imx_dma_request(i2c_imx, (dma_addr_t)phy_addr)) { + dev_info(&pdev->dev, + "can't request dma chan, faild use dma.\n"); + i2c_imx->use_dma = false; + } else { + i2c_imx->use_dma = true; + } OK, looking at this one more time, why don't you wrap the allocation of i2c_imx- >dma into i2c_imx_dma_request() ? Even better, you can allocate *dma as a local variable in i2c_imx_dma_request() and then assign it into i2c_imx->dma only at the end of the i2c_imx_dma_request() function , at the point where you are sure nothing failed. Then you can check i2c_imx->dma != NULL throughout the code to check if the DMA is available, no ? Shawn, Wolfram, am I talking nonsense or am I just not connecting ? Best regards, Marek Vasut
On Wed, Mar 26, 2014 at 08:26:27AM +0100, Marek Vasut wrote: > > > I think we disconnected here, sorry. Why can you not use (i2c_imx->dma != > > > NULL) instead of (i2c_imx->use_dma == true) please ? > > > > But there are two judge conditions. But only the "i2c_imx->dma", but also > > whether "i2c_imx_dma_request" success. > > > > "i2c_imx->use_dma == true" be equivalent to "i2c_imx->dma != NULL && > > !i2c_imx_dma_request()" > > + /* Init DMA config if support*/ > + i2c_imx->dma = devm_kzalloc(&pdev->dev, sizeof(struct imx_i2c_dma), > + GFP_KERNEL); > + if (!i2c_imx->dma) { > + dev_info(&pdev->dev, > + "can't allocate dma struct faild use dma.\n"); > + i2c_imx->use_dma = false; > + } else if (i2c_imx_dma_request(i2c_imx, (dma_addr_t)phy_addr)) { > + dev_info(&pdev->dev, > + "can't request dma chan, faild use dma.\n"); > + i2c_imx->use_dma = false; > + } else { > + i2c_imx->use_dma = true; > + } > > OK, looking at this one more time, why don't you wrap the allocation of i2c_imx- > >dma into i2c_imx_dma_request() ? Even better, you can allocate *dma as a local > variable in i2c_imx_dma_request() and then assign it into i2c_imx->dma only at > the end of the i2c_imx_dma_request() function , at the point where you are sure > nothing failed. Then you can check i2c_imx->dma != NULL throughout the code to > check if the DMA is available, no ? > > Shawn, Wolfram, am I talking nonsense or am I just not connecting ? I'm with you, Marek. Shawn
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index db895fb..6bfe23c 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -37,22 +37,27 @@ /** Includes ******************************************************************* *******************************************************************************/ -#include <linux/init.h> -#include <linux/kernel.h> -#include <linux/module.h> +#include <linux/clk.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/dma-mapping.h> +#include <linux/dmaengine.h> +#include <linux/dmapool.h> #include <linux/errno.h> #include <linux/err.h> #include <linux/interrupt.h> -#include <linux/delay.h> #include <linux/i2c.h> +#include <linux/init.h> #include <linux/io.h> -#include <linux/sched.h> -#include <linux/platform_device.h> -#include <linux/clk.h> -#include <linux/slab.h> +#include <linux/kernel.h> +#include <linux/module.h> #include <linux/of.h> #include <linux/of_device.h> +#include <linux/of_dma.h> #include <linux/platform_data/i2c-imx.h> +#include <linux/platform_device.h> +#include <linux/sched.h> +#include <linux/slab.h> /** 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 +205,9 @@ struct imx_i2c_struct { int stopped; unsigned int ifdr; /* IMX_I2C_IFDR */ const struct imx_i2c_hwdata *hwdata; + + struct imx_i2c_dma *dma; + bool use_dma; }; static const struct imx_i2c_hwdata imx1_i2c_hwdata = { @@ -254,9 +278,121 @@ 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 = i2c_imx->dma; + struct dma_slave_config dma_sconfig; + struct device *dev = &i2c_imx->adapter.dev; + int ret; + + dma->chan_tx = dma_request_slave_channel(dev, "tx"); + if (!dma->chan_tx) { + dev_err(dev, "Dma tx channel request failed!\n"); + return -ENODEV; + } + + 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_err(dev, "Dma slave config failed, err = %d\n", ret); + goto fail_tx; + } + + dma->chan_rx = dma_request_slave_channel(dev, "rx"); + if (!dma->chan_rx) { + dev_err(dev, "Dma rx channel request failed!\n"); + 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_err(dev, "Dma slave config failed, err = %d\n", ret); + goto fail_rx; + } + + init_completion(&dma->cmd_complete); + + return 0; + +fail_rx: + dma_release_channel(dma->chan_rx); +fail_tx: + dma_release_channel(dma->chan_tx); + 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; + + dma->dma_buf = dma_map_single(dma->chan_using->device->dev, msgs->buf, + dma->dma_len, dma->dma_data_dir); + if (dma_mapping_error(dma->chan_using->device->dev, dma->dma_buf)) { + dev_err(dev, "dma_map_single 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"); + dma_unmap_single(dma->chan_using->device->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 *************************************** *******************************************************************************/ - static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy) { unsigned long orig_jiffies = jiffies; @@ -427,46 +563,103 @@ 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; dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n", __func__, msgs->addr << 1); - /* 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__); + if (i2c_imx->use_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 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); + 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 */ + 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); + } + + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + temp &= ~I2CR_DMAEN; + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); + + /* write the last byte */ + 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(&i2c_imx->adapter.dev, "<%s> write data\n", __func__); + + /* 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); + 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; dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n", __func__, (msgs->addr << 1) | 0x01); + /* write slave address */ imx_i2c_write_reg((msgs->addr << 1) | 0x01, i2c_imx, IMX_I2C_I2DR); result = i2c_imx_trx_complete(i2c_imx); @@ -488,33 +681,78 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__); - /* read data */ - for (i = 0; i < msgs->len; i++) { - result = i2c_imx_trx_complete(i2c_imx); + if (i2c_imx->use_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; + 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)) { + + 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); + } + + 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(&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); + "<%s> read byte: B%d=0x%X\n", + __func__, i, msgs->buf[i]); } - 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]); + 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; } @@ -601,6 +839,7 @@ 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__); @@ -611,6 +850,7 @@ static int i2c_imx_probe(struct platform_device *pdev) } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + phy_addr = res->start; base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(base)) return PTR_ERR(base); @@ -696,6 +936,21 @@ 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*/ + i2c_imx->dma = devm_kzalloc(&pdev->dev, sizeof(struct imx_i2c_dma), + GFP_KERNEL); + if (!i2c_imx->dma) { + dev_info(&pdev->dev, + "can't allocate dma struct faild use dma.\n"); + i2c_imx->use_dma = false; + } else if (i2c_imx_dma_request(i2c_imx, (dma_addr_t)phy_addr)) { + dev_info(&pdev->dev, + "can't request dma chan, faild use dma.\n"); + i2c_imx->use_dma = false; + } else { + i2c_imx->use_dma = true; + } + return 0; /* Return OK */ } @@ -707,6 +962,9 @@ static int i2c_imx_remove(struct platform_device *pdev) dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n"); i2c_del_adapter(&i2c_imx->adapter); + if (i2c_imx->use_dma) + i2c_imx_dma_free(i2c_imx); + /* setup chip registers to defaults */ imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR); imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IFDR);
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 <yao.yuan@freescale.com> --- drivers/i2c/busses/i2c-imx.c | 354 +++++++++++++++++++++++++++++++++++++------ 1 file changed, 306 insertions(+), 48 deletions(-)