Re: [PATCH 5/5] ACPI: Add support for platform bus type

[Rafael J. Wysocki]

On Wednesday, October 31, 2012 11:34:24 PM Yinghai Lu wrote:
> On Wed, Oct 31, 2012 at 2:36 AM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> > From: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> >
> > With ACPI 5 it is now possible to enumerate traditional SoC
> > peripherals, like serial bus controllers and slave devices behind
> > them.  These devices are typically based on IP-blocks used in many
> > existing SoC platforms and platform drivers for them may already
> > be present in the kernel tree.
> >
> > To make driver "porting" more straightforward, add ACPI support to
> > the platform bus type.  Instead of writing ACPI "glue" drivers for
> > the existing platform drivers, register the platform bus type with
> > ACPI to create platform device objects for the drivers and bind the
> > corresponding ACPI handles to those platform devices.
> >
> > This should allow us to reuse the existing platform drivers for the
> > devices in question with the minimum amount of modifications.
> >
> > This changeset is based on Mika Westerberg's and Mathias Nyman's
> > work.
> >
> > Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
> > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > ---
> >  drivers/acpi/Makefile        |    1
> >  drivers/acpi/acpi_platform.c |  285 +++++++++++++++++++++++++++++++++++++++++++
> >  drivers/acpi/internal.h      |    7 +
> >  drivers/acpi/scan.c          |   16 ++
> >  drivers/base/platform.c      |    5
> >  5 files changed, 313 insertions(+), 1 deletion(-)
> 
> this patch is too big, and should be split to at least two or more.
> 
> >  create mode 100644 drivers/acpi/acpi_platform.c
> >
> > Index: linux/drivers/acpi/Makefile
> > ===================================================================
> > --- linux.orig/drivers/acpi/Makefile
> > +++ linux/drivers/acpi/Makefile
> > @@ -37,6 +37,7 @@ acpi-y                                += processor_core.o
> >  acpi-y                         += ec.o
> >  acpi-$(CONFIG_ACPI_DOCK)       += dock.o
> >  acpi-y                         += pci_root.o pci_link.o pci_irq.o pci_bind.o
> > +acpi-y                         += acpi_platform.o
> >  acpi-y                         += power.o
> >  acpi-y                         += event.o
> >  acpi-y                         += sysfs.o
> > Index: linux/drivers/acpi/acpi_platform.c
> > ===================================================================
> > --- /dev/null
> > +++ linux/drivers/acpi/acpi_platform.c
> > @@ -0,0 +1,285 @@
> > +/*
> > + * ACPI support for platform bus type.
> > + *
> > + * Copyright (C) 2012, Intel Corporation
> > + * Authors: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> > + *          Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
> > + *          Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#include <linux/acpi.h>
> > +#include <linux/device.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +
> > +ACPI_MODULE_NAME("platform");
> > +
> > +struct resource_info {
> > +       struct device *dev;
> > +       struct resource *res;
> > +       size_t n, cur;
> > +};
> > +
> > +static acpi_status acpi_platform_count_resources(struct acpi_resource *res,
> > +                                                void *data)
> > +{
> > +       struct acpi_resource_extended_irq *acpi_xirq;
> > +       struct resource_info *ri = data;
> > +
> > +       switch (res->type) {
> > +       case ACPI_RESOURCE_TYPE_FIXED_MEMORY32:
> > +       case ACPI_RESOURCE_TYPE_IRQ:
> > +               ri->n++;
> > +               break;
> > +       case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
> > +               acpi_xirq = &res->data.extended_irq;
> > +               ri->n += acpi_xirq->interrupt_count;
> > +               break;
> > +       case ACPI_RESOURCE_TYPE_ADDRESS32:
> > +               if (res->data.address32.resource_type == ACPI_IO_RANGE)
> > +                       ri->n++;
> > +               break;
> > +       }
> > +
> > +       return AE_OK;
> > +}
> > +
> > +static acpi_status acpi_platform_add_resources(struct acpi_resource *res,
> > +                                              void *data)
> > +{
> > +       struct acpi_resource_fixed_memory32 *acpi_mem;
> > +       struct acpi_resource_address32 *acpi_add32;
> > +       struct acpi_resource_extended_irq *acpi_xirq;
> > +       struct acpi_resource_irq *acpi_irq;
> > +       struct resource_info *ri = data;
> > +       struct resource *r;
> > +       int irq, i;
> > +
> > +       switch (res->type) {
> > +       case ACPI_RESOURCE_TYPE_FIXED_MEMORY32:
> > +               acpi_mem = &res->data.fixed_memory32;
> > +               r = &ri->res[ri->cur++];
> > +
> > +               r->start = acpi_mem->address;
> > +               r->end = r->start + acpi_mem->address_length - 1;
> > +               r->flags = IORESOURCE_MEM;
> > +
> > +               dev_dbg(ri->dev, "Memory32Fixed %pR\n", r);
> > +               break;
> > +
> > +       case ACPI_RESOURCE_TYPE_ADDRESS32:
> > +               acpi_add32 = &res->data.address32;
> > +
> > +               if (acpi_add32->resource_type == ACPI_IO_RANGE) {
> > +                       r = &ri->res[ri->cur++];
> > +                       r->start = acpi_add32->minimum;
> > +                       r->end = r->start + acpi_add32->address_length - 1;
> > +                       r->flags = IORESOURCE_IO;
> > +                       dev_dbg(ri->dev, "Address32 %pR\n", r);
> > +               }
> > +               break;
> > +
> > +       case ACPI_RESOURCE_TYPE_IRQ:
> > +               acpi_irq = &res->data.irq;
> > +               r = &ri->res[ri->cur++];
> > +
> > +               irq = acpi_register_gsi(ri->dev,
> > +                                       acpi_irq->interrupts[0],
> > +                                       acpi_irq->triggering,
> > +                                       acpi_irq->polarity);
> > +
> > +               r->start = r->end = irq;
> > +               r->flags = IORESOURCE_IRQ;
> > +
> > +               dev_dbg(ri->dev, "IRQ %pR\n", r);
> > +               break;
> > +
> > +       case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
> > +               acpi_xirq = &res->data.extended_irq;
> > +
> > +               for (i = 0; i < acpi_xirq->interrupt_count; i++, ri->cur++) {
> > +                       r = &ri->res[ri->cur];
> > +                       irq = acpi_register_gsi(ri->dev,
> > +                                               acpi_xirq->interrupts[i],
> > +                                               acpi_xirq->triggering,
> > +                                               acpi_xirq->polarity);
> > +
> > +                       r->start = r->end = irq;
> > +                       r->flags = IORESOURCE_IRQ;
> > +
> > +                       dev_dbg(ri->dev, "Interrupt %pR\n", r);
> > +               }
> > +               break;
> > +       }
> > +
> > +       return AE_OK;
> > +}
> > +
> 
> could be shared with pci root or pnp devices?

Maybe.

> > +static acpi_status acpi_platform_get_device_uid(struct acpi_device *adev,
> > +                                               int *uid)
> > +{
> > +       struct acpi_device_info *info;
> > +       acpi_status status;
> > +
> > +       status = acpi_get_object_info(adev->handle, &info);
> > +       if (ACPI_FAILURE(status))
> > +               return status;
> > +
> > +       status = AE_NOT_EXIST;
> > +       if ((info->valid & ACPI_VALID_UID) &&
> > +            !kstrtoint(info->unique_id.string, 0, uid))
> > +               status = AE_OK;
> > +
> > +       kfree(info);
> > +       return status;
> > +}
> > +
> > +/**
> > + * acpi_create_platform_device - Create platform device for ACPI device node
> > + * @adev: ACPI device node to create a platform device for.
> > + *
> > + * Check if the given @adev can be represented as a platform device and, if
> > + * that's the case, create and register a platform device, populate its common
> > + * resources and returns a pointer to it.  Otherwise, return %NULL.
> > + *
> > + * The platform device's name will be taken from the @adev's _HID and _UID.
> > + */
> > +struct platform_device *acpi_create_platform_device(struct acpi_device *adev)
> > +{
> > +       struct platform_device *pdev = NULL;
> > +       struct acpi_device *acpi_parent;
> > +       struct device *parent = NULL;
> > +       struct resource_info ri;
> > +       acpi_status status;
> > +       int devid;
> > +
> > +       /* If the ACPI node already has a physical device attached, skip it. */
> > +       if (adev->physical_node_count)
> > +               return NULL;
> > +
> > +       /* Use the UID of the device as the new platform device id if found. */
> > +       status = acpi_platform_get_device_uid(adev, &devid);
> > +       if (ACPI_FAILURE(status))
> > +               devid = -1;
> > +
> > +       memset(&ri, 0, sizeof(ri));
> > +
> > +       /* First, count the resources. */
> > +       status = acpi_walk_resources(adev->handle, METHOD_NAME__CRS,
> > +                                    acpi_platform_count_resources, &ri);
> > +       if (ACPI_FAILURE(status) || !ri.n)
> > +               return NULL;
> > +
> > +       /* Next, allocate memory for all the resources and populate it. */
> > +       ri.dev = &adev->dev;
> > +       ri.res = kzalloc(ri.n * sizeof(struct resource), GFP_KERNEL);
> > +       if (!ri.res) {
> > +               dev_err(&adev->dev,
> > +                       "failed to allocate memory for resources\n");
> > +               return NULL;
> > +       }
> > +
> > +       status = acpi_walk_resources(adev->handle, METHOD_NAME__CRS,
> > +                                    acpi_platform_add_resources, &ri);
> > +       if (ACPI_FAILURE(status)) {
> > +               dev_err(&adev->dev, "failed to walk resources\n");
> > +               goto out;
> > +       }
> > +
> > +       if (WARN_ON(ri.n != ri.cur))
> > +               goto out;
> > +
> > +       /*
> > +        * If the ACPI node has a parent and that parent has a physical device
> > +        * attached to it, that physical device should be the parent of the
> > +        * platform device we are about to create.
> > +        */
> > +       acpi_parent = adev->parent;
> > +       if (acpi_parent) {
> > +               struct acpi_device_physical_node *entry;
> > +               struct list_head *list;
> > +
> > +               mutex_lock(&acpi_parent->physical_node_lock);
> > +               list = &acpi_parent->physical_node_list;
> > +               if (!list_empty(list)) {
> > +                       entry = list_first_entry(list,
> > +                                       struct acpi_device_physical_node,
> > +                                       node);
> > +                       parent = entry->dev;
> > +               }
> > +               mutex_unlock(&acpi_parent->physical_node_lock);
> > +       }
> > +       pdev = platform_device_register_resndata(parent, acpi_device_hid(adev),
> > +                                                devid, ri.res, ri.n, NULL, 0);
> > +       if (IS_ERR(pdev)) {
> > +               dev_err(&adev->dev, "platform device creation failed: %ld\n",
> > +                       PTR_ERR(pdev));
> > +               pdev = NULL;
> > +       } else {
> > +               dev_dbg(&adev->dev, "created platform device %s\n",
> > +                       dev_name(&pdev->dev));
> > +       }
> > +
> > + out:
> > +       kfree(ri.res);
> > +       return pdev;
> > +}
> > +
> > +static acpi_status acpi_platform_match(acpi_handle handle, u32 depth,
> > +                                      void *data, void **return_value)
> > +{
> > +       struct platform_device *pdev = data;
> > +       struct acpi_device *adev;
> > +       acpi_status status;
> > +
> > +       status = acpi_bus_get_device(handle, &adev);
> > +       if (ACPI_FAILURE(status))
> > +               return status;
> > +
> > +       /* Skip ACPI devices that have physical device attached */
> > +       if (adev->physical_node_count)
> > +               return AE_OK;
> > +
> > +       if (!strcmp(pdev->name, acpi_device_hid(adev))) {
> > +               int devid;
> > +
> > +               /* Check that both name and UID match if it exists */
> > +               status = acpi_platform_get_device_uid(adev, &devid);
> > +               if (ACPI_FAILURE(status))
> > +                       devid = -1;
> > +
> > +               if (pdev->id != devid)
> > +                       return AE_OK;
> > +
> > +               *(acpi_handle *)return_value = handle;
> > +               return AE_CTRL_TERMINATE;
> > +       }
> > +
> > +       return AE_OK;
> > +}
> > +
> > +static int acpi_platform_find_device(struct device *dev, acpi_handle *handle)
> > +{
> > +       struct platform_device *pdev = to_platform_device(dev);
> > +
> > +       *handle = NULL;
> > +       acpi_get_devices(pdev->name, acpi_platform_match, pdev, handle);
> > +
> > +       return *handle ? 0 : -ENODEV;
> > +}
> > +
> > +static struct acpi_bus_type acpi_platform_bus = {
> > +       .bus = &platform_bus_type,
> > +       .find_device = acpi_platform_find_device,
> > +};
> > +
> > +static int __init acpi_platform_init(void)
> > +{
> > +       return register_acpi_bus_type(&acpi_platform_bus);
> > +}
> > +arch_initcall(acpi_platform_init);
> > Index: linux/drivers/acpi/internal.h
> > ===================================================================
> > --- linux.orig/drivers/acpi/internal.h
> > +++ linux/drivers/acpi/internal.h
> > @@ -93,4 +93,11 @@ static inline int suspend_nvs_save(void)
> >  static inline void suspend_nvs_restore(void) {}
> >  #endif
> >
> > +/*--------------------------------------------------------------------------
> > +                               Platform bus support
> > +  -------------------------------------------------------------------------- */
> > +struct platform_device;
> > +
> > +struct platform_device *acpi_create_platform_device(struct acpi_device *adev);
> > +
> >  #endif /* _ACPI_INTERNAL_H_ */
> > Index: linux/drivers/acpi/scan.c
> > ===================================================================
> > --- linux.orig/drivers/acpi/scan.c
> > +++ linux/drivers/acpi/scan.c
> > @@ -29,6 +29,15 @@ extern struct acpi_device *acpi_root;
> >
> >  static const char *dummy_hid = "device";
> >
> > +/*
> > + * The following ACPI IDs are known to be suitable for representing as
> > + * platform devices.
> > + */
> > +static const struct acpi_device_id acpi_platform_device_ids[] = {
> > +
> 
> ?

Yes, empty list.  We're going to populate it later.

> > +       { }
> > +};
> > +
> >  static LIST_HEAD(acpi_device_list);
> >  static LIST_HEAD(acpi_bus_id_list);
> >  DEFINE_MUTEX(acpi_device_lock);
> > @@ -1544,8 +1553,13 @@ static acpi_status acpi_bus_check_add(ac
> >          */
> >         device = NULL;
> >         acpi_bus_get_device(handle, &device);
> > -       if (ops->acpi_op_add && !device)
> > +       if (ops->acpi_op_add && !device) {
> >                 acpi_add_single_object(&device, handle, type, sta, ops);
> > +               /* Is the device a known good platform device? */
> > +               if (device
> > +                   && !acpi_match_device_ids(device, acpi_platform_device_ids))
> > +                       acpi_create_platform_device(device);
> > +       }
> 
> That is ugly! any reason for not using acpi_driver for them.

Yes, a couple of reasons.  First off, there are existing platform drivers for
these things already and there's no reason for creating a "glue" layer between
those drivers and struct acpi_device objects.  Second, we're going to get rid
of acpi_driver things entirely going forward (the existing ones will be replaced
by platform drivers or included into the ACPI core).

> there is not reason to treat those platform_device different from pci
> root device and other pnp device.

Well, I agree. :-)

So those things you're talking about we'll be platform devices too in the
future.

> something like attached patch. .add of acpi_driver ops could call
> acpi_create_platform_device.

Been there, decided to do it differently this time.

Thanks,
Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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