[PATCH 1/2 take #2] libata: Support PIO polling-only hosts.

[PATCH 1/2 take #2] libata: Support PIO polling-only hosts.

[Paul Mundt]

By default ata_host_activate() expects a valid IRQ in order to
successfully register the host. This patch enables a special case
for registering polling-only hosts that either don't have IRQs
or have buggy IRQ generation (either in terms of handling or
sensing), which otherwise work fine.

Hosts that want to use polling mode can simply set ATA_FLAG_PIO_POLLING
and pass in an invalid IRQ.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

---

 drivers/ata/libata-core.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index ec3ce12..89fd0e9 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -7178,6 +7178,10 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
  *	request IRQ and register it.  This helper takes necessasry
  *	arguments and performs the three steps in one go.
  *
+ *	An invalid IRQ skips the IRQ registration and expects the host to
+ *	have set polling mode on the port. In this case, @irq_handler
+ *	should be NULL.
+ *
  *	LOCKING:
  *	Inherited from calling layer (may sleep).
  *
@@ -7194,6 +7198,12 @@ int ata_host_activate(struct ata_host *host, int irq,
 	if (rc)
 		return rc;
 
+	/* Special case for polling mode */
+	if (!irq) {
+		WARN_ON(irq_handler);
+		return ata_host_register(host, sht);
+	}
+
 	rc = devm_request_irq(host->dev, irq, irq_handler, irq_flags,
 			      dev_driver_string(host->dev), host);
 	if (rc)

[PATCH 2/2 take #2] libata: pata_platform: Support polling-mode configuration.

[Paul Mundt]

Some SH boards (old R2D-1 boards) have generally not had working CF
under libata, due to both buswidth issues (handled by Aoi Shinkai
in 43f4b8c7578b928892b6f01d374346ae14e5eb70), and buggy interrupt
controllers. For these sorts of boards simply disabling the IRQ and
polling ends up working fine.

This conditionalizes the IRQ resource for pata_platform and lets
platforms that want to use polling mode simply omit the resource
entirely.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

---

 drivers/ata/pata_platform.c |   35 ++++++++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/drivers/ata/pata_platform.c b/drivers/ata/pata_platform.c
index fc72a96..ac03a90 100644
--- a/drivers/ata/pata_platform.c
+++ b/drivers/ata/pata_platform.c
@@ -1,7 +1,7 @@
 /*
  * Generic platform device PATA driver
  *
- * Copyright (C) 2006  Paul Mundt
+ * Copyright (C) 2006 - 2007  Paul Mundt
  *
  * Based on pata_pcmcia:
  *
@@ -22,7 +22,7 @@
 #include <linux/pata_platform.h>
 
 #define DRV_NAME "pata_platform"
-#define DRV_VERSION "1.1"
+#define DRV_VERSION "1.2"
 
 static int pio_mask = 1;
 
@@ -120,15 +120,20 @@ static void pata_platform_setup_port(struct ata_ioports *ioaddr,
  *	Register a platform bus IDE interface. Such interfaces are PIO and we
  *	assume do not support IRQ sharing.
  *
- *	Platform devices are expected to contain 3 resources per port:
+ *	Platform devices are expected to contain at least 2 resources per port:
  *
  *		- I/O Base (IORESOURCE_IO or IORESOURCE_MEM)
  *		- CTL Base (IORESOURCE_IO or IORESOURCE_MEM)
+ *
+ *	and optionally:
+ *
  *		- IRQ	   (IORESOURCE_IRQ)
  *
  *	If the base resources are both mem types, the ioremap() is handled
  *	here. For IORESOURCE_IO, it's assumed that there's no remapping
  *	necessary.
+ *
+ *	If no IRQ resource is present, PIO polling mode is used instead.
  */
 static int __devinit pata_platform_probe(struct platform_device *pdev)
 {
@@ -137,11 +142,12 @@ static int __devinit pata_platform_probe(struct platform_device *pdev)
 	struct ata_port *ap;
 	struct pata_platform_info *pp_info;
 	unsigned int mmio;
+	int irq;
 
 	/*
 	 * Simple resource validation ..
 	 */
-	if (unlikely(pdev->num_resources != 3)) {
+	if ((pdev->num_resources != 3) && (pdev->num_resources != 2)) {
 		dev_err(&pdev->dev, "invalid number of resources\n");
 		return -EINVAL;
 	}
@@ -173,6 +179,13 @@ static int __devinit pata_platform_probe(struct platform_device *pdev)
 		(ctl_res->flags == IORESOURCE_MEM));
 
 	/*
+	 * And the IRQ
+	 */
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		irq = 0;	/* no irq */
+
+	/*
 	 * Now that that's out of the way, wire up the port..
 	 */
 	host = ata_host_alloc(&pdev->dev, 1);
@@ -185,6 +198,14 @@ static int __devinit pata_platform_probe(struct platform_device *pdev)
 	ap->flags |= ATA_FLAG_SLAVE_POSS;
 
 	/*
+	 * Use polling mode if there's no IRQ
+	 */
+	if (!irq) {
+		ap->flags |= ATA_FLAG_PIO_POLLING;
+		ata_port_desc(ap, "no IRQ, using PIO polling");
+	}
+
+	/*
 	 * Handle the MMIO case
 	 */
 	if (mmio) {
@@ -213,9 +234,9 @@ static int __devinit pata_platform_probe(struct platform_device *pdev)
 		      (unsigned long long)ctl_res->start);
 
 	/* activate */
-	return ata_host_activate(host, platform_get_irq(pdev, 0),
-				 ata_interrupt, pp_info ? pp_info->irq_flags
-				 : 0, &pata_platform_sht);
+	return ata_host_activate(host, irq, irq ? ata_interrupt : NULL,
+				 pp_info ? pp_info->irq_flags : 0,
+				 &pata_platform_sht);
 }
 
 /**

Re: [PATCH 1/2 take #2] libata: Support PIO polling-only hosts.

[Alan Cox]

On Thu, 8 Nov 2007 11:14:56 +0900
Paul Mundt <lethal@linux-sh.org> wrote:

> By default ata_host_activate() expects a valid IRQ in order to
> successfully register the host. This patch enables a special case
> for registering polling-only hosts that either don't have IRQs
> or have buggy IRQ generation (either in terms of handling or
> sensing), which otherwise work fine.
> 
> Hosts that want to use polling mode can simply set ATA_FLAG_PIO_POLLING
> and pass in an invalid IRQ.
> 
> Signed-off-by: Paul Mundt <lethal@linux-sh.org>

Acked-by: Alan Cox <alan@redhat.com>


May need to tweak polled isapnp support (or add it) to avoid the WARN but
I will take care of it

Re: [PATCH 1/2 take #2] libata: Support PIO polling-only hosts.

[Jeff Garzik]

On Thu, Nov 08, 2007 at 11:14:56AM +0900, Paul Mundt wrote:
> By default ata_host_activate() expects a valid IRQ in order to
> successfully register the host. This patch enables a special case
> for registering polling-only hosts that either don't have IRQs
> or have buggy IRQ generation (either in terms of handling or
> sensing), which otherwise work fine.
> 
> Hosts that want to use polling mode can simply set ATA_FLAG_PIO_POLLING
> and pass in an invalid IRQ.
> 
> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
> 

applied 1-2