Re: [PATCH 02/10] Driver core: Add iommu_ops to bus_type

Roedel, Joerg
2011-09-14T12:46:32Z

On Tue, Sep 13, 2011 at 12:21:26PM -0400, Greg KH wrote:
> On Tue, Sep 13, 2011 at 05:38:11PM +0200, Roedel, Joerg wrote:
> > On Tue, Sep 13, 2011 at 10:58:55AM -0400, Greg KH wrote:
> > > On Tue, Sep 13, 2011 at 04:54:02PM +0200, Roedel, Joerg wrote:
> > > > --- a/include/linux/device.h
> > > > +++ b/include/linux/device.h
> > > > @@ -22,6 +22,7 @@
> > > > #include <linux/types.h>
> > > > #include <linux/module.h>
> > > > #include <linux/pm.h>
> > > > +#include <linux/iommu.h>
> > >
> > > Ick, please don't add new #includes to device.h, it makes the whole
> > > build slower. Just pre-declare the structure and all should be fine.
> >
> > Hmm, since linux/iommu.h provides 'struct iommu_ops', and this patch
> > adds a 'struct iommu_ops' to 'struct bus_type', wouldn't a simple
> > forward declaration make the bus_type incomplete in most other places?
>
> No, just like it doesn't make iommu.h incomplete as you used a struct
> bus_type there.

Ah right, because bus->iommu_ops is just a pointer the full type
definition for iommu_ops is only needed when this pointer is actually
dereferenced. I updated the patch. Please find it below.

>From 6e0e1c3b997e06539f7bda80f46ffe9fb04aab4e Mon Sep 17 00:00:00 2001
From: Joerg Roedel <joerg.roedel@amd.com>
Date: Fri, 26 Aug 2011 16:48:26 +0200
Subject: [PATCH 02/10] Driver core: Add iommu_ops to bus_type

This is the starting point to make the iommu_ops used for
the iommu-api a per-bus-type structure. It is required to
easily implement bus-specific setup in the iommu-layer.
The first user will be the iommu-group attribute in sysfs.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
drivers/base/bus.c | 29 +++++++++++++++++++++++++++++
drivers/iommu/iommu.c | 4 ++++
include/linux/device.h | 10 ++++++++++
include/linux/iommu.h | 2 ++
4 files changed, 45 insertions(+), 0 deletions(-)

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 000e7b2..b3014fe 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -1028,6 +1028,35 @@ void bus_sort_breadthfirst(struct bus_type *bus,
}
EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);

+#ifdef CONFIG_IOMMU_API
+/**
+ * bus_set_iommu - set iommu-callbacks for the bus
+ * @bus: bus.
+ * @ops: the callbacks provided by the iommu-driver
+ *
+ * This function is called by an iommu driver to set the iommu methods
+ * used for a particular bus. Drivers for devices on that bus can use
+ * the iommu-api after these ops are registered.
+ * This special function is needed because IOMMUs are usually devices on
+ * the bus itself, so the iommu drivers are not initialized when the bus
+ * is set up. With this function the iommu-driver can set the iommu-ops
+ * afterwards.
+ */
+int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops)
+{
+ if (bus->iommu_ops != NULL)
+ return -EBUSY;
+
+ bus->iommu_ops = ops;
+
+ /* Do IOMMU specific setup for this bus-type */
+ iommu_bus_init(bus, ops);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(bus_set_iommu);
+#endif
+
int __init buses_init(void)
{
bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 30b0644..3b24a5b 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -34,6 +34,10 @@ void register_iommu(struct iommu_ops *ops)
iommu_ops = ops;
}

+void iommu_bus_init(struct bus_type *bus, struct iommu_ops *ops)
+{
+}
+
bool iommu_found(void)
{
return iommu_ops != NULL;
diff --git a/include/linux/device.h b/include/linux/device.h
index c20dfbf..490382b 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -33,6 +33,7 @@ struct class;
struct subsys_private;
struct bus_type;
struct device_node;
+struct iommu_ops;

struct bus_attribute {
struct attribute attr;
@@ -46,6 +47,7 @@ struct bus_attribute bus_attr_##_name = __ATTR(_name, _mode, _show, _store)
extern int __must_check bus_create_file(struct bus_type *,
struct bus_attribute *);
extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
+extern void iommu_bus_init(struct bus_type *bus, struct iommu_ops *ops);

/**
* struct bus_type - The bus type of the device
@@ -67,6 +69,9 @@ extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
* @resume: Called to bring a device on this bus out of sleep mode.
* @pm: Power management operations of this bus, callback the specific
* device driver's pm-ops.
+ * @iommu_ops IOMMU specific operations for this bus, used to attach IOMMU
+ * driver implementations to a bus and allow the driver to do
+ * bus-specific setup
* @p: The private data of the driver core, only the driver core can
* touch this.
*
@@ -96,6 +101,8 @@ struct bus_type {

const struct dev_pm_ops *pm;

+ struct iommu_ops *iommu_ops;
+
struct subsys_private *p;
};

@@ -148,6 +155,9 @@ extern int bus_unregister_notifier(struct bus_type *bus,
#define BUS_NOTIFY_UNBOUND_DRIVER 0x00000006 /* driver is unbound
from the device */

+/* IOMMU related bus functions */
+int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops);
+
extern struct kset *bus_get_kset(struct bus_type *bus);
extern struct klist *bus_get_device_klist(struct bus_type *bus);

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 6470cd8..4739e36 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -25,6 +25,7 @@
#define IOMMU_WRITE (2)
#define IOMMU_CACHE (4) /* DMA cache coherency */

+struct bus_type;
struct device;

struct iommu_domain {
@@ -52,6 +53,7 @@ struct iommu_ops {
};

extern void register_iommu(struct iommu_ops *ops);
+extern void iommu_bus_init(struct bus_type *bus, struct iommu_ops *ops);
extern bool iommu_found(void);
extern struct iommu_domain *iommu_domain_alloc(void);
extern void iommu_domain_free(struct iommu_domain *domain);
--
1.7.4.1

--
AMD Operating System Research Center

Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo, Andrew Bowd
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632