[PATCH 0/3] hpet: convert from ACPI to PNP driver

[PATCH 0/3] hpet: convert from ACPI to PNP driver

[Bjorn Helgaas]

The hpet driver parses ACPI _CRS data manually, but PNPACPI already does
that, and it does a more complete job, so we can simplify the hpet driver
quite a bit by taking advantage of that.

---

Bjorn Helgaas (3):
      hpet: convert to PNP driver
      hpet: pass physical address, not entire hpet_data, to hpet_is_known()
      MAINTAINERS: remove obsolete HPET ACPI entry


 MAINTAINERS         |    5 --
 drivers/char/hpet.c |  110 ++++++++++++++-------------------------------------
 2 files changed, 30 insertions(+), 85 deletions(-)

[PATCH 1/3] hpet: convert to PNP driver

[Bjorn Helgaas]

PNPACPI already parses _CRS, and does a more complete job than we did here,
so let's just take advantage of that.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
---

 drivers/char/hpet.c |  103 +++++++++++++--------------------------------------
 1 files changed, 27 insertions(+), 76 deletions(-)


diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index e481c59..65a9aa8 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -31,6 +31,7 @@
 #include <linux/seq_file.h>
 #include <linux/bitops.h>
 #include <linux/clocksource.h>
+#include <linux/pnp.h>
 
 #include <asm/current.h>
 #include <asm/uaccess.h>
@@ -40,7 +41,6 @@
 #include <asm/div64.h>
 
 #include <linux/acpi.h>
-#include <acpi/acpi_bus.h>
 #include <linux/hpet.h>
 
 /*
@@ -899,100 +899,53 @@ int hpet_alloc(struct hpet_data *hdp)
 	return 0;
 }
 
-static acpi_status hpet_resources(struct acpi_resource *res, void *data)
+static int hpet_pnp_add(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
 {
-	struct hpet_data *hdp;
-	acpi_status status;
-	struct acpi_resource_address64 addr;
-
-	hdp = data;
-
-	status = acpi_resource_to_address64(res, &addr);
-
-	if (ACPI_SUCCESS(status)) {
-		hdp->hd_phys_address = addr.minimum;
-		hdp->hd_address = ioremap(addr.minimum, addr.address_length);
-
-		if (hpet_is_known(hdp)) {
-			iounmap(hdp->hd_address);
-			return AE_ALREADY_EXISTS;
-		}
-	} else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
-		struct acpi_resource_fixed_memory32 *fixmem32;
-
-		fixmem32 = &res->data.fixed_memory32;
-		if (!fixmem32)
-			return AE_NO_MEMORY;
+	struct hpet_data data;
+	struct resource *mem, *irq;
+	int i;
 
-		hdp->hd_phys_address = fixmem32->address;
-		hdp->hd_address = ioremap(fixmem32->address,
-						HPET_RANGE_SIZE);
+	memset(&data, 0, sizeof(data));
 
-		if (hpet_is_known(hdp)) {
-			iounmap(hdp->hd_address);
-			return AE_ALREADY_EXISTS;
-		}
-	} else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
-		struct acpi_resource_extended_irq *irqp;
-		int i, irq;
+	mem = pnp_get_resource(dev, IORESOURCE_MEM, 0);
+	if (!mem)
+		return -ENODEV;
 
-		irqp = &res->data.extended_irq;
+	data.hd_phys_address = mem->start;
 
-		for (i = 0; i < irqp->interrupt_count; i++) {
-			irq = acpi_register_gsi(NULL, irqp->interrupts[i],
-				      irqp->triggering, irqp->polarity);
-			if (irq < 0)
-				return AE_ERROR;
+	if (hpet_is_known(&data))
+		return -EBUSY;
 
-			hdp->hd_irq[hdp->hd_nirqs] = irq;
-			hdp->hd_nirqs++;
-		}
+	i = 0;
+	while (data.hd_nirqs < ARRAY_SIZE(data.hd_irq)) {
+		irq = pnp_get_resource(dev, IORESOURCE_IRQ, i++);
+		if (pnp_resource_valid(irq) && pnp_resource_enabled(irq))
+			data.hd_irq[data.hd_nirqs++] = irq->start;
 	}
-
-	return AE_OK;
-}
-
-static int hpet_acpi_add(struct acpi_device *device)
-{
-	acpi_status result;
-	struct hpet_data data;
-
-	memset(&data, 0, sizeof(data));
-
-	result =
-	    acpi_walk_resources(device->handle, METHOD_NAME__CRS,
-				hpet_resources, &data);
-
-	if (ACPI_FAILURE(result))
+	if (!data.hd_nirqs)
 		return -ENODEV;
 
-	if (!data.hd_address || !data.hd_nirqs) {
-		printk("%s: no address or irqs in _CRS\n", __func__);
-		return -ENODEV;
-	}
+	data.hd_address = ioremap(mem->start, resource_size(mem));
 
 	return hpet_alloc(&data);
 }
 
-static int hpet_acpi_remove(struct acpi_device *device, int type)
+static void hpet_pnp_remove(struct pnp_dev *dev)
 {
 	/* XXX need to unregister clocksource, dealloc mem, etc */
-	return -EINVAL;
 }
 
-static const struct acpi_device_id hpet_device_ids[] = {
+static const struct pnp_device_id hpet_device_ids[] = {
 	{"PNP0103", 0},
 	{"", 0},
 };
 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
 
-static struct acpi_driver hpet_acpi_driver = {
+static struct pnp_driver hpet_pnp_driver = {
 	.name = "hpet",
-	.ids = hpet_device_ids,
-	.ops = {
-		.add = hpet_acpi_add,
-		.remove = hpet_acpi_remove,
-		},
+	.id_table = hpet_device_ids,
+	.probe = hpet_pnp_add,
+	.remove = hpet_pnp_remove,
 };
 
 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
@@ -1007,7 +960,7 @@ static int __init hpet_init(void)
 
 	sysctl_header = register_sysctl_table(dev_root);
 
-	result = acpi_bus_register_driver(&hpet_acpi_driver);
+	result = pnp_register_driver(&hpet_pnp_driver);
 	if (result < 0) {
 		if (sysctl_header)
 			unregister_sysctl_table(sysctl_header);
@@ -1020,13 +973,11 @@ static int __init hpet_init(void)
 
 static void __exit hpet_exit(void)
 {
-	acpi_bus_unregister_driver(&hpet_acpi_driver);
+	pnp_unregister_driver(&hpet_pnp_driver);
 
 	if (sysctl_header)
 		unregister_sysctl_table(sysctl_header);
 	misc_deregister(&hpet_misc);
-
-	return;
 }
 
 module_init(hpet_init);

Re: [PATCH 1/3] hpet: convert to PNP driver

[Venkatesh Pallipadi]

On Wed, Mar 17, 2010 at 10:35 AM, Bjorn Helgaas <bjorn.helgaas@hp.com> wrote:
>
> PNPACPI already parses _CRS, and does a more complete job than we did here,
> so let's just take advantage of that.
>

Patch looks good.
One comment is that we now have a dependency on CONFIG_PNP. That
probably needs to be added in drivers/char/Kconfig. But, that also
means we may fail for users who do not have PNP in their config today.
May be just select PNP when HPET is selected?

> Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
> ---
>
>  drivers/char/hpet.c |  103 +++++++++++++--------------------------------------
>  1 files changed, 27 insertions(+), 76 deletions(-)
>
>
>
> -       if (!data.hd_address || !data.hd_nirqs) {
> -               printk("%s: no address or irqs in _CRS\n", __func__);
> -               return -ENODEV;
> -       }
> +       data.hd_address = ioremap(mem->start, resource_size(mem));
>
>        return hpet_alloc(&data);
>  }

Not a problem with this patch. But, don't we have a problem of rogue
ioremap when hpet_alloc() fails here?

Thanks,
Venki

Re: [PATCH 1/3] hpet: convert to PNP driver

[Bjorn Helgaas]

On Wednesday 17 March 2010 04:18:27 pm Venkatesh Pallipadi wrote:
> On Wed, Mar 17, 2010 at 10:35 AM, Bjorn Helgaas <bjorn.helgaas@hp.com> wrote:
> >
> > PNPACPI already parses _CRS, and does a more complete job than we did here,
> > so let's just take advantage of that.
> 
> Patch looks good.
> One comment is that we now have a dependency on CONFIG_PNP. That
> probably needs to be added in drivers/char/Kconfig. But, that also
> means we may fail for users who do not have PNP in their config today.
> May be just select PNP when HPET is selected?

Good point; I missed that.  I could just add #ifdef CONFIG_PNP around
the relevant code in hpet.c.  That's the typical way we handle this.

drivers/char/hpet.c already depends on ACPI for another reason
(acpi_irq_model), and we do select PNP whenever CONFIG_ACPI=y, so
I don't think the CONFIG_PNP=n case will arise in practice.  But
it'd probably be better to have the #ifdef wrapper than to have the
implicit dependency on the "select PNP" in drivers/acpi/Kconfig.

> > Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
> > ---
> >
> >  drivers/char/hpet.c |  103 +++++++++++++--------------------------------------
> >  1 files changed, 27 insertions(+), 76 deletions(-)
> >
> >
> >
> > -       if (!data.hd_address || !data.hd_nirqs) {
> > -               printk("%s: no address or irqs in _CRS\n", __func__);
> > -               return -ENODEV;
> > -       }
> > +       data.hd_address = ioremap(mem->start, resource_size(mem));
> >
> >        return hpet_alloc(&data);
> >  }
> 
> Not a problem with this patch. But, don't we have a problem of rogue
> ioremap when hpet_alloc() fails here?

You're right.  I'll add a patch to fix that while I'm at it.

Bjorn

[PATCH 2/3] hpet: pass physical address, not entire hpet_data, to hpet_is_known()

[Bjorn Helgaas]

No functional change; hpet_is_known() only needs the physical address,
so supplying that instead of the whole struct hpet_data makes the callers
a little simpler.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
---

 drivers/char/hpet.c |   11 +++++------
 1 files changed, 5 insertions(+), 6 deletions(-)


diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index 65a9aa8..4c508df 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -662,12 +662,12 @@ static const struct file_operations hpet_fops = {
 	.mmap = hpet_mmap,
 };
 
-static int hpet_is_known(struct hpet_data *hdp)
+static int hpet_is_known(unsigned long phys_address)
 {
 	struct hpets *hpetp;
 
 	for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
-		if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
+		if (hpetp->hp_hpet_phys == phys_address)
 			return 1;
 
 	return 0;
@@ -788,7 +788,7 @@ int hpet_alloc(struct hpet_data *hdp)
 	 * If platform dependent code has allocated the hpet that
 	 * ACPI has also reported, then we catch it here.
 	 */
-	if (hpet_is_known(hdp)) {
+	if (hpet_is_known(hdp->hd_phys_address)) {
 		printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 			__func__);
 		return 0;
@@ -911,9 +911,7 @@ static int hpet_pnp_add(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
 	if (!mem)
 		return -ENODEV;
 
-	data.hd_phys_address = mem->start;
-
-	if (hpet_is_known(&data))
+	if (hpet_is_known(mem->start))
 		return -EBUSY;
 
 	i = 0;
@@ -925,6 +923,7 @@ static int hpet_pnp_add(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
 	if (!data.hd_nirqs)
 		return -ENODEV;
 
+	data.hd_phys_address = mem->start;
 	data.hd_address = ioremap(mem->start, resource_size(mem));
 
 	return hpet_alloc(&data);

Re: [PATCH 2/3] hpet: pass physical address, not entire hpet_data, to hpet_is_known()

[Clemens Ladisch]

Bjorn Helgaas wrote:
> No functional change; hpet_is_known() only needs the physical address,
> so supplying that instead of the whole struct hpet_data makes the callers
> a little simpler.
> 
> Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>

Acked-by: Clemens Ladisch <clemens@ladisch.de>

[PATCH 3/3] MAINTAINERS: remove obsolete HPET ACPI entry

[Bjorn Helgaas]

Bob Picco is no longer at HP.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
---

 MAINTAINERS |    5 -----
 1 files changed, 0 insertions(+), 5 deletions(-)


diff --git a/MAINTAINERS b/MAINTAINERS
index 47cc449..30ba4e9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2664,11 +2664,6 @@ HPET:	x86_64
 M:	Vojtech Pavlik <vojtech@suse.cz>
 S:	Maintained
 
-HPET:	ACPI
-M:	Bob Picco <bob.picco@hp.com>
-S:	Maintained
-F:	drivers/char/hpet.c
-
 HPFS FILESYSTEM
 M:	Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
 W:	http://artax.karlin.mff.cuni.cz/~mikulas/vyplody/hpfs/index-e.cgi