| Message ID | 20241127074458.2102112-1-carlos.song@nxp.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v3] i2c: imx: support DMA defer probing | expand |
> -----Original Message----- > From: Marc Kleine-Budde <mkl@pengutronix.de> > Sent: Wednesday, November 27, 2024 3:42 PM > To: Carlos Song <carlos.song@nxp.com> > Cc: Frank Li <frank.li@nxp.com>; o.rempel@pengutronix.de; > kernel@pengutronix.de; andi.shyti@kernel.org; shawnguo@kernel.org; > s.hauer@pengutronix.de; festevam@gmail.com; linux-i2c@vger.kernel.org; > imx@lists.linux.dev; linux-arm-kernel@lists.infradead.org; > linux-kernel@vger.kernel.org > Subject: [EXT] Re: [PATCH v3] i2c: imx: support DMA defer probing > > On 27.11.2024 15:44:58, carlos.song@nxp.com wrote: > > From: Carlos Song <carlos.song@nxp.com> > > > > Return -EPROBE_DEFER when dma_request_slave_channel() because DMA > > driver have not ready yet. > > > > Move i2c_imx_dma_request() before registering I2C adapter to avoid > > infinite loop of .probe() calls to the same driver, see "e8c220fac415 > > Revert "i2c: imx: improve the error handling in i2c_imx_dma_request()"" > > and "Documentation/driver-api/driver-model/driver.rst". > > > > Use CPU mode to avoid stuck registering i2c adapter when DMA resources > > are unavailable. > > > > Signed-off-by: Carlos Song <carlos.song@nxp.com> > > Signed-off-by: Clark Wang <xiaoning.wang@nxp.com> > > --- > > Change for V3: > > - According to Marc's comment, remove error print when defer probe. > > Add info log when DMA has not been enabled and add error log when > > DMA error, both won't stuck the i2c adapter register, just for reminding, > > i2c adapter is working only in PIO mode. > > Change for V2: > > - According to Frank's comments, wrap at 75 char and Simplify fix code > > at i2c_imx_dma_request(). > > - Use strict patch check, fix alignment warning at > > i2c_imx_dma_request() > > --- > > drivers/i2c/busses/i2c-imx.c | 31 +++++++++++++++++++++++-------- > > 1 file changed, 23 insertions(+), 8 deletions(-) > > > > diff --git a/drivers/i2c/busses/i2c-imx.c > > b/drivers/i2c/busses/i2c-imx.c index 5ed4cb61e262..47112a38d034 100644 > > --- a/drivers/i2c/busses/i2c-imx.c > > +++ b/drivers/i2c/busses/i2c-imx.c > > @@ -397,17 +397,16 @@ static void i2c_imx_reset_regs(struct > > imx_i2c_struct *i2c_imx) } > > > > /* Functions for DMA support */ > > -static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, > > - dma_addr_t phy_addr) > > +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; > > + struct device *dev = i2c_imx->adapter.dev.parent; > > int ret; > > > > dma = devm_kzalloc(dev, sizeof(*dma), GFP_KERNEL); > > if (!dma) > > - return; > > + return -ENOMEM; > > > > dma->chan_tx = dma_request_chan(dev, "tx"); > > if (IS_ERR(dma->chan_tx)) { > > @@ -452,7 +451,7 @@ static void i2c_imx_dma_request(struct > imx_i2c_struct *i2c_imx, > > dev_info(dev, "using %s (tx) and %s (rx) for DMA transfers\n", > > dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx)); > > > > - return; > > + return 0; > > > > fail_rx: > > dma_release_channel(dma->chan_rx); > > @@ -460,6 +459,8 @@ static void i2c_imx_dma_request(struct > imx_i2c_struct *i2c_imx, > > dma_release_channel(dma->chan_tx); > > fail_al: > > devm_kfree(dev, dma); > > + > > + return ret; > > } > > > > static void i2c_imx_dma_callback(void *arg) @@ -1803,6 +1804,23 @@ > > static int i2c_imx_probe(struct platform_device *pdev) > > if (ret == -EPROBE_DEFER) > > goto clk_notifier_unregister; > > > > + /* > > + * Init DMA config if supported, -ENODEV means DMA not enabled at > > + * this platform, that is not a real error, so just remind "only > > + * PIO mode is used". If DMA is enabled, but meet error when request > > + * DMA channel, error should be showed in probe error log. PIO mode > > + * should be available regardless of DMA. > > + */ > > + ret = i2c_imx_dma_request(i2c_imx, phy_addr); > > + if (ret) { > > + if (ret == -EPROBE_DEFER) > > + goto clk_notifier_unregister; > > + else if (ret == -ENODEV) > > + dev_info(&pdev->dev, "Only use PIO mode\n"); > > On a system without DMA configured, with this patch we now get this info > message that wasn't there before. I think this might annoy some people, so you > should remove it. > :-) hhh, get it. How about change to dev_dbg? > regards, > Marc > > > + else > > + dev_err_probe(&pdev->dev, ret, "Failed to setup DMA, only use > PIO mode\n"); > > + } > > + > > /* Add I2C adapter */ > > ret = i2c_add_numbered_adapter(&i2c_imx->adapter); > > if (ret < 0) > > @@ -1817,9 +1835,6 @@ 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 supported */ > > - i2c_imx_dma_request(i2c_imx, phy_addr); > > - > > return 0; /* Return OK */ > > > > clk_notifier_unregister: > > -- > > 2.34.1 > > > > > > -- > Pengutronix e.K. | Marc Kleine-Budde | > Embedded Linux | https://www.pengutronix.de | > Vertretung Nürnberg | Phone: +49-5121-206917-129 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 |
> -----Original Message----- > From: Marc Kleine-Budde <mkl@pengutronix.de> > Sent: Wednesday, November 27, 2024 3:59 PM > To: Carlos Song <carlos.song@nxp.com> > Cc: Frank Li <frank.li@nxp.com>; o.rempel@pengutronix.de; > kernel@pengutronix.de; andi.shyti@kernel.org; shawnguo@kernel.org; > s.hauer@pengutronix.de; festevam@gmail.com; linux-i2c@vger.kernel.org; > imx@lists.linux.dev; linux-arm-kernel@lists.infradead.org; > linux-kernel@vger.kernel.org > Subject: Re: RE: [EXT] Re: [PATCH v3] i2c: imx: support DMA defer > probing > > On 27.11.2024 07:48:13, Carlos Song wrote: > > > > static void i2c_imx_dma_callback(void *arg) @@ -1803,6 +1804,23 > > > > @@ static int i2c_imx_probe(struct platform_device *pdev) > > > > if (ret == -EPROBE_DEFER) > > > > goto clk_notifier_unregister; > > > > > > > > + /* > > > > + * Init DMA config if supported, -ENODEV means DMA not enabled at > > > > + * this platform, that is not a real error, so just remind "only > > > > + * PIO mode is used". If DMA is enabled, but meet error when > request > > > > + * DMA channel, error should be showed in probe error log. PIO mode > > > > + * should be available regardless of DMA. > > > > + */ > > > > + ret = i2c_imx_dma_request(i2c_imx, phy_addr); > > > > + if (ret) { > > > > + if (ret == -EPROBE_DEFER) > > > > + goto clk_notifier_unregister; > > > > + else if (ret == -ENODEV) > > > > + dev_info(&pdev->dev, "Only use PIO mode\n"); > > > > > > On a system without DMA configured, with this patch we now get > > > this info message that wasn't there before. I think this might > > > annoy some people, so you should remove it. > > > > > > > :-) hhh, get it. > > Some things look reasonable when discussing the patch, but when you > see the new, cleaned-up version, you immediately realize that this is > going to annoy people :) > Such valuable experience~ Thank you very much, Marc! This is definitely what I haven't thought about before. I'll pay more attention in the future. :) > > How about change to dev_dbg? > > Good idea. > Will fix it at V4. > regards, > Marc > > -- > Pengutronix e.K. | Marc Kleine-Budde | > Embedded Linux | https://www.pengutronix.de | > Vertretung Nürnberg | Phone: +49-5121-206917-129 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 |
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index 5ed4cb61e262..47112a38d034 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -397,17 +397,16 @@ static void i2c_imx_reset_regs(struct imx_i2c_struct *i2c_imx) } /* Functions for DMA support */ -static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, - dma_addr_t phy_addr) +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; + struct device *dev = i2c_imx->adapter.dev.parent; int ret; dma = devm_kzalloc(dev, sizeof(*dma), GFP_KERNEL); if (!dma) - return; + return -ENOMEM; dma->chan_tx = dma_request_chan(dev, "tx"); if (IS_ERR(dma->chan_tx)) { @@ -452,7 +451,7 @@ static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, dev_info(dev, "using %s (tx) and %s (rx) for DMA transfers\n", dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx)); - return; + return 0; fail_rx: dma_release_channel(dma->chan_rx); @@ -460,6 +459,8 @@ static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, dma_release_channel(dma->chan_tx); fail_al: devm_kfree(dev, dma); + + return ret; } static void i2c_imx_dma_callback(void *arg) @@ -1803,6 +1804,23 @@ static int i2c_imx_probe(struct platform_device *pdev) if (ret == -EPROBE_DEFER) goto clk_notifier_unregister; + /* + * Init DMA config if supported, -ENODEV means DMA not enabled at + * this platform, that is not a real error, so just remind "only + * PIO mode is used". If DMA is enabled, but meet error when request + * DMA channel, error should be showed in probe error log. PIO mode + * should be available regardless of DMA. + */ + ret = i2c_imx_dma_request(i2c_imx, phy_addr); + if (ret) { + if (ret == -EPROBE_DEFER) + goto clk_notifier_unregister; + else if (ret == -ENODEV) + dev_info(&pdev->dev, "Only use PIO mode\n"); + else + dev_err_probe(&pdev->dev, ret, "Failed to setup DMA, only use PIO mode\n"); + } + /* Add I2C adapter */ ret = i2c_add_numbered_adapter(&i2c_imx->adapter); if (ret < 0) @@ -1817,9 +1835,6 @@ 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 supported */ - i2c_imx_dma_request(i2c_imx, phy_addr); - return 0; /* Return OK */ clk_notifier_unregister: