[PATCH v3 0/4] mmc: atmel-mci: cleanup and probe deferring

[PATCH v3 0/4] mmc: atmel-mci: cleanup and probe deferring

[Ludovic Desroches]

Hi Ulf,

I have rebased my series on your next branch but I didn't have any conflict and
a warning on the whole series with checkpatch so please tell me if something
goes wrong.

Regards

Ludovic

Ludovic Desroches (4):
  mmc: atmel-mci: remove useless DMA stuff for non-dt devices
  mmc: atmel-mci: remove __init/__exit attributes
  mmc: atmel-mci: stop using specific initcall
  mmc: atmel-mci: use probe deferring if dma controller is not ready yet

 drivers/mmc/host/atmel-mci.c | 76 +++++++++++++++++---------------------------
 1 file changed, 29 insertions(+), 47 deletions(-)

-- 
2.0.3

[PATCH v3 1/4] mmc: atmel-mci: remove useless DMA stuff for non-dt devices

[Ludovic Desroches]

All devices with a DMA controller are DT compliant and legacy support
has been removed. For those reasons, some DMA stuff is useless.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
---
 drivers/mmc/host/atmel-mci.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index de2287c..f187e75 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -2274,17 +2274,9 @@ static void atmci_cleanup_slot(struct atmel_mci_slot *slot,
 
 static bool atmci_configure_dma(struct atmel_mci *host)
 {
-	struct mci_platform_data	*pdata;
-	dma_cap_mask_t mask;
-
 	if (host == NULL)
 		return false;
 
-	pdata = host->pdev->dev.platform_data;
-
-	dma_cap_zero(mask);
-	dma_cap_set(DMA_SLAVE, mask);
-
 	host->dma.chan = dma_request_slave_channel(&host->pdev->dev, "rxtx");
 	if (!host->dma.chan) {
 		dev_warn(&host->pdev->dev, "no DMA channel available\n");
-- 
2.0.3

[PATCH v3 2/4] mmc: atmel-mci: remove __init/__exit attributes

[Ludovic Desroches]

Using __init/__exit attributes can cause several breakages so remove
them.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
---
 drivers/mmc/host/atmel-mci.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index f187e75..064358d 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -2140,7 +2140,7 @@ static irqreturn_t atmci_detect_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static int __init atmci_init_slot(struct atmel_mci *host,
+static int atmci_init_slot(struct atmel_mci *host,
 		struct mci_slot_pdata *slot_data, unsigned int id,
 		u32 sdc_reg, u32 sdio_irq)
 {
@@ -2302,7 +2302,7 @@ static bool atmci_configure_dma(struct atmel_mci *host)
  * HSMCI provides DMA support and a new config register but no more supports
  * PDC.
  */
-static void __init atmci_get_cap(struct atmel_mci *host)
+static void atmci_get_cap(struct atmel_mci *host)
 {
 	unsigned int version;
 
@@ -2351,7 +2351,7 @@ static void __init atmci_get_cap(struct atmel_mci *host)
 	}
 }
 
-static int __init atmci_probe(struct platform_device *pdev)
+static int atmci_probe(struct platform_device *pdev)
 {
 	struct mci_platform_data	*pdata;
 	struct atmel_mci		*host;
@@ -2502,7 +2502,7 @@ err_init_slot:
 	return ret;
 }
 
-static int __exit atmci_remove(struct platform_device *pdev)
+static int atmci_remove(struct platform_device *pdev)
 {
 	struct atmel_mci	*host = platform_get_drvdata(pdev);
 	unsigned int		i;
@@ -2565,7 +2565,7 @@ static const struct dev_pm_ops atmci_dev_pm_ops = {
 };
 
 static struct platform_driver atmci_driver = {
-	.remove		= __exit_p(atmci_remove),
+	.remove		= atmci_remove,
 	.driver		= {
 		.name		= "atmel_mci",
 		.of_match_table	= of_match_ptr(atmci_dt_ids),
@@ -2573,12 +2573,12 @@ static struct platform_driver atmci_driver = {
 	},
 };
 
-static int __init atmci_init(void)
+static int atmci_init(void)
 {
 	return platform_driver_probe(&atmci_driver, atmci_probe);
 }
 
-static void __exit atmci_exit(void)
+static void atmci_exit(void)
 {
 	platform_driver_unregister(&atmci_driver);
 }
-- 
2.0.3

Re: [PATCH v3 2/4] mmc: atmel-mci: remove __init/__exit attributes

[Russell King - ARM Linux]

On Fri, Nov 28, 2014 at 03:08:04PM +0100, Ludovic Desroches wrote:
> Using __init/__exit attributes can cause several breakages so remove
> them.

I've really no idea why people jump overboard with these things - it
seems people go from one extreme to the other (adding lots of __init /
__exit annotations everywhere to removing them all), but:

> @@ -2573,12 +2573,12 @@ static struct platform_driver atmci_driver = {
>  	},
>  };
>  
> -static int __init atmci_init(void)
> +static int atmci_init(void)
>  {
>  	return platform_driver_probe(&atmci_driver, atmci_probe);
>  }
>  
> -static void __exit atmci_exit(void)
> +static void atmci_exit(void)
>  {
>  	platform_driver_unregister(&atmci_driver);
>  }

These last two are totally fine to leave there.

-- 
FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up
according to speedtest.net.

[PATCH v3 3/4] mmc: atmel-mci: stop using specific initcall

[Ludovic Desroches]

No more use late initcall to manage probing order. Use probe deferring
if needed.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
---
 drivers/mmc/host/atmel-mci.c | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 064358d..00f6088 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -2565,6 +2565,7 @@ static const struct dev_pm_ops atmci_dev_pm_ops = {
 };
 
 static struct platform_driver atmci_driver = {
+	.probe		= atmci_probe,
 	.remove		= atmci_remove,
 	.driver		= {
 		.name		= "atmel_mci",
@@ -2572,19 +2573,7 @@ static struct platform_driver atmci_driver = {
 		.pm		= &atmci_dev_pm_ops,
 	},
 };
-
-static int atmci_init(void)
-{
-	return platform_driver_probe(&atmci_driver, atmci_probe);
-}
-
-static void atmci_exit(void)
-{
-	platform_driver_unregister(&atmci_driver);
-}
-
-late_initcall(atmci_init); /* try to load after dma driver when built-in */
-module_exit(atmci_exit);
+module_platform_driver(atmci_driver);
 
 MODULE_DESCRIPTION("Atmel Multimedia Card Interface driver");
 MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
-- 
2.0.3

[PATCH v3 4/4] mmc: atmel-mci: use probe deferring if dma controller is not ready yet

[Ludovic Desroches]

Return probe defer if requesting a dma channel without a dma controller
probed.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
---
 drivers/mmc/host/atmel-mci.c | 49 ++++++++++++++++++++++----------------------
 1 file changed, 25 insertions(+), 24 deletions(-)

diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 00f6088..0a96819 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -2272,29 +2272,26 @@ static void atmci_cleanup_slot(struct atmel_mci_slot *slot,
 	mmc_free_host(slot->mmc);
 }
 
-static bool atmci_configure_dma(struct atmel_mci *host)
+static int atmci_configure_dma(struct atmel_mci *host)
 {
-	if (host == NULL)
-		return false;
+	int ret = 0;
 
-	host->dma.chan = dma_request_slave_channel(&host->pdev->dev, "rxtx");
-	if (!host->dma.chan) {
-		dev_warn(&host->pdev->dev, "no DMA channel available\n");
-		return false;
-	} else {
-		dev_info(&host->pdev->dev,
-					"using %s for DMA transfers\n",
-					dma_chan_name(host->dma.chan));
-
-		host->dma_conf.src_addr = host->mapbase + ATMCI_RDR;
-		host->dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-		host->dma_conf.src_maxburst = 1;
-		host->dma_conf.dst_addr = host->mapbase + ATMCI_TDR;
-		host->dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-		host->dma_conf.dst_maxburst = 1;
-		host->dma_conf.device_fc = false;
-		return true;
-	}
+	host->dma.chan = dma_request_slave_channel_reason(&host->pdev->dev, "rxtx");
+	if (IS_ERR(host->dma.chan))
+		return PTR_ERR(host->dma.chan);
+
+	dev_info(&host->pdev->dev, "using %s for DMA transfers\n",
+		 dma_chan_name(host->dma.chan));
+
+	host->dma_conf.src_addr = host->mapbase + ATMCI_RDR;
+	host->dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	host->dma_conf.src_maxburst = 1;
+	host->dma_conf.dst_addr = host->mapbase + ATMCI_TDR;
+	host->dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	host->dma_conf.dst_maxburst = 1;
+	host->dma_conf.device_fc = false;
+
+	return ret;
 }
 
 /*
@@ -2411,7 +2408,10 @@ static int atmci_probe(struct platform_device *pdev)
 
 	/* Get MCI capabilities and set operations according to it */
 	atmci_get_cap(host);
-	if (atmci_configure_dma(host)) {
+	ret = atmci_configure_dma(host);
+	if (ret == -EPROBE_DEFER)
+		goto err_dma_probe_defer;
+	if (ret == 0) {
 		host->prepare_data = &atmci_prepare_data_dma;
 		host->submit_data = &atmci_submit_data_dma;
 		host->stop_transfer = &atmci_stop_transfer_dma;
@@ -2496,8 +2496,9 @@ err_init_slot:
 	pm_runtime_put_noidle(&pdev->dev);
 
 	del_timer_sync(&host->timer);
-	if (host->dma.chan)
+	if (!IS_ERR(host->dma.chan))
 		dma_release_channel(host->dma.chan);
+err_dma_probe_defer:
 	free_irq(irq, host);
 	return ret;
 }
@@ -2523,7 +2524,7 @@ static int atmci_remove(struct platform_device *pdev)
 	atmci_readl(host, ATMCI_SR);
 
 	del_timer_sync(&host->timer);
-	if (host->dma.chan)
+	if (!IS_ERR(host->dma.chan))
 		dma_release_channel(host->dma.chan);
 
 	free_irq(platform_get_irq(pdev, 0), host);
-- 
2.0.3

Re: [PATCH v3 4/4] mmc: atmel-mci: use probe deferring if dma controller is not ready yet

[Russell King - ARM Linux]

Let's look at the resulting code:

On Fri, Nov 28, 2014 at 03:08:06PM +0100, Ludovic Desroches wrote:
> +static int atmci_configure_dma(struct atmel_mci *host)
>  {
> +	int ret = 0;
>  
> +	host->dma.chan = dma_request_slave_channel_reason(&host->pdev->dev, "rxtx");
> +	if (IS_ERR(host->dma.chan))
> +		return PTR_ERR(host->dma.chan);
> +
> +	dev_info(&host->pdev->dev, "using %s for DMA transfers\n",
> +		 dma_chan_name(host->dma.chan));
> +
> +	host->dma_conf.src_addr = host->mapbase + ATMCI_RDR;
> +	host->dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> +	host->dma_conf.src_maxburst = 1;
> +	host->dma_conf.dst_addr = host->mapbase + ATMCI_TDR;
> +	host->dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> +	host->dma_conf.dst_maxburst = 1;
> +	host->dma_conf.device_fc = false;
> +
> +	return ret;
>  }

I think you can clean this up a little further - what do you notice
about the value of "ret" here?

-- 
FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up
according to speedtest.net.

Re: [PATCH v3 4/4] mmc: atmel-mci: use probe deferring if dma controller is not ready yet

[Ludovic Desroches]

On Fri, Nov 28, 2014 at 02:19:03PM +0000, Russell King - ARM Linux wrote:
> Let's look at the resulting code:
> 
> On Fri, Nov 28, 2014 at 03:08:06PM +0100, Ludovic Desroches wrote:
> > +static int atmci_configure_dma(struct atmel_mci *host)
> >  {
> > +	int ret = 0;
> >  
> > +	host->dma.chan = dma_request_slave_channel_reason(&host->pdev->dev, "rxtx");
> > +	if (IS_ERR(host->dma.chan))
> > +		return PTR_ERR(host->dma.chan);
> > +
> > +	dev_info(&host->pdev->dev, "using %s for DMA transfers\n",
> > +		 dma_chan_name(host->dma.chan));
> > +
> > +	host->dma_conf.src_addr = host->mapbase + ATMCI_RDR;
> > +	host->dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> > +	host->dma_conf.src_maxburst = 1;
> > +	host->dma_conf.dst_addr = host->mapbase + ATMCI_TDR;
> > +	host->dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> > +	host->dma_conf.dst_maxburst = 1;
> > +	host->dma_conf.device_fc = false;
> > +
> > +	return ret;
> >  }
> 
> I think you can clean this up a little further - what do you notice
> about the value of "ret" here?

I think I see what you mean :) The fix I have merged for this patch
makes ret useless.

> 
> -- 
> FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up
> according to speedtest.net.