Re: [PATCH] SuperHyway bus support

[Paul Mundt <paul.mundt@nokia.com>]

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On Wed, Jan 12, 2005 at 12:17:22AM -0800, Greg KH wrote:
> >  drivers/Makefile                         |    1 
> >  drivers/sh/Makefile                      |    6 
> >  drivers/sh/superhyway/Makefile           |    7 +
> >  drivers/sh/superhyway/superhyway-sysfs.c |   47 +++++++
> >  drivers/sh/superhyway/superhyway.c       |  205 +++++++++++++++++++++++++++++++
> 
> No Kconfig file to enable this option?
> 
It's in the arch-specific code, it will go in with the next sh64 update.
Though I can always add a drivers/sh/Kconfig that does this too (I didn't
think it was worth the trouble for a single option at the moment).

> > +static struct device superhyway_bus_device = {
> > +	.bus_id = "superhyway",
> > +};
> 
> This device doesn't have a release function, as it's tied to the module.
> Are you sure it's race free?  :)
> 
I wasn't aware that it needed one. I copied this mostly verbatim from the
platform bus code where there is also no release function.

Looking at some of the other bus drivers, I see that w1 makes use of a release
function for its bus device, but it does this only for completion handling in
a kernel thread, which clearly has no application here.

The only thing I would see a release routine being useful for in this case
would be for refcounting, but the driver core already does that for us. Is
there something obvious that I'm missing?

> > +static int __init superhyway_init(void)
> > +{
> > +	extern int superhyway_scan_bus(void);
> 
> This should go in a .h file somewhere.
> 
Done.

> > +EXPORT_SYMBOL(superhyway_bus_type);
> > +EXPORT_SYMBOL(superhyway_add_device);
> > +EXPORT_SYMBOL(superhyway_register_driver);
> > +EXPORT_SYMBOL(superhyway_unregister_driver);
> 
> Did you forget a .h file with these function prototypes?
> 
Yes, it would seem that way. Here we go again:

 drivers/sh/Makefile                      |    6 
 drivers/sh/superhyway/Makefile           |    7 +
 drivers/sh/superhyway/superhyway-sysfs.c |   45 ++++++
 drivers/sh/superhyway/superhyway.c       |  201 +++++++++++++++++++++++++++++++
 include/linux/superhyway.h               |   79 ++++++++++++
 5 files changed, 338 insertions(+)

diff -urN linux-2.6/drivers/sh/Makefile linux-sh64-2.6/drivers/sh/Makefile
--- linux-2.6/drivers/sh/Makefile	1970-01-01 02:00:00.000000000 +0200
+++ linux-sh64-2.6/drivers/sh/Makefile	2004-12-07 14:16:02.000000000 +0200
@@ -0,0 +1,6 @@
+#
+# Makefile for the SuperH specific drivers.
+#
+
+obj-$(CONFIG_SUPERHYWAY) += superhyway/
+
diff -urN linux-2.6/drivers/sh/superhyway/Makefile linux-sh64-2.6/drivers/sh/superhyway/Makefile
--- linux-2.6/drivers/sh/superhyway/Makefile	1970-01-01 02:00:00.000000000 +0200
+++ linux-sh64-2.6/drivers/sh/superhyway/Makefile	2005-01-07 18:19:26.000000000 +0200
@@ -0,0 +1,7 @@
+#
+# Makefile for the SuperHyway bus drivers.
+#
+
+obj-$(CONFIG_SUPERHYWAY)	+= superhyway.o
+obj-$(CONFIG_SYSFS)		+= superhyway-sysfs.o
+
diff -urN linux-2.6/drivers/sh/superhyway/superhyway.c linux-sh64-2.6/drivers/sh/superhyway/superhyway.c
--- linux-2.6/drivers/sh/superhyway/superhyway.c	1970-01-01 02:00:00.000000000 +0200
+++ linux-sh64-2.6/drivers/sh/superhyway/superhyway.c	2005-01-12 14:37:54.675100400 +0200
@@ -0,0 +1,201 @@
+/*
+ * drivers/sh/superhyway/superhyway.c
+ *
+ * SuperHyway Bus Driver
+ *
+ * Copyright (C) 2004, 2005  Paul Mundt <lethal@linux-sh.org>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/superhyway.h>
+
+static int superhyway_devices;
+
+static struct device superhyway_bus_device = {
+	.bus_id = "superhyway",
+};
+
+static void superhyway_device_release(struct device *dev)
+{
+	kfree(to_superhyway_device(dev));
+}
+
+/**
+ * superhyway_add_device - Add a SuperHyway module
+ * @mod_id: Module ID (taken from MODULE.VCR.MOD_ID).
+ * @base: Physical address where module is mapped.
+ * @vcr: VCR value.
+ *
+ * This is responsible for adding a new SuperHyway module. This sets up a new
+ * struct superhyway_device for the module being added. Each one of @mod_id,
+ * @base, and @vcr are registered with the new device for further use
+ * elsewhere.
+ *
+ * Devices are initially added in the order that they are scanned (from the
+ * top-down of the memory map), and are assigned an ID based on the order that
+ * they are added. Any manual addition of a module will thus get the ID after
+ * the devices already discovered regardless of where it resides in memory.
+ *
+ * Further work can and should be done in superhyway_scan_bus(), to be sure
+ * that any new modules are properly discovered and subsequently registered.
+ */
+int superhyway_add_device(unsigned int mod_id, unsigned long base,
+			  unsigned long long vcr)
+{
+	struct superhyway_device *dev;
+
+	dev = kmalloc(sizeof(struct superhyway_device), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	memset(dev, 0, sizeof(struct superhyway_device));
+
+	dev->id.id = mod_id;
+	sprintf(dev->name, "SuperHyway device %04x", dev->id.id);
+
+	dev->vcr		= *((struct vcr_info *)(&vcr));
+	dev->resource.name	= dev->name;
+	dev->resource.start	= base;
+	dev->resource.end	= dev->resource.start + 0x01000000;
+	dev->dev.parent		= &superhyway_bus_device;
+	dev->dev.bus		= &superhyway_bus_type;
+	dev->dev.release	= superhyway_device_release;
+
+	sprintf(dev->dev.bus_id, "%02x", superhyway_devices);
+
+	superhyway_devices++;
+
+	return device_register(&dev->dev);
+}
+
+static int __init superhyway_init(void)
+{
+	device_register(&superhyway_bus_device);
+	return superhyway_scan_bus();
+}
+
+postcore_initcall(superhyway_init);
+
+static const struct superhyway_device_id *
+superhyway_match_id(const struct superhyway_device_id *ids,
+		    struct superhyway_device *dev)
+{
+	while (ids->id) {
+		if (ids->id == dev->id.id)
+			return ids;
+
+		ids++;
+	}
+
+	return NULL;
+}
+
+static int superhyway_device_probe(struct device *dev)
+{
+	struct superhyway_device *shyway_dev = to_superhyway_device(dev);
+	struct superhyway_driver *shyway_drv = to_superhyway_driver(dev->driver);
+
+	if (shyway_drv && shyway_drv->probe) {
+		const struct superhyway_device_id *id;
+
+		id = superhyway_match_id(shyway_drv->id_table, shyway_dev);
+		if (id)
+			return shyway_drv->probe(shyway_dev, id);
+	}
+
+	return -ENODEV;
+}
+
+static int superhyway_device_remove(struct device *dev)
+{
+	struct superhyway_device *shyway_dev = to_superhyway_device(dev);
+	struct superhyway_driver *shyway_drv = to_superhyway_driver(dev->driver);
+
+	if (shyway_drv && shyway_drv->remove) {
+		shyway_drv->remove(shyway_dev);
+		return 0;
+	}
+
+	return -ENODEV;
+}
+
+/**
+ * superhyway_register_driver - Register a new SuperHyway driver
+ * @drv: SuperHyway driver to register.
+ *
+ * This registers the passed in @drv. Any devices matching the id table will
+ * automatically be populated and handed off to the driver's specified probe
+ * routine.
+ */
+int superhyway_register_driver(struct superhyway_driver *drv)
+{
+	drv->drv.name	= drv->name;
+	drv->drv.bus	= &superhyway_bus_type;
+	drv->drv.probe	= superhyway_device_probe;
+	drv->drv.remove	= superhyway_device_remove;
+
+	return driver_register(&drv->drv);
+}
+
+/**
+ * superhyway_unregister_driver - Unregister a SuperHyway driver
+ * @drv: SuperHyway driver to unregister.
+ *
+ * This cleans up after superhyway_register_driver(), and should be invoked in
+ * the exit path of any module drivers.
+ */
+void superhyway_unregister_driver(struct superhyway_driver *drv)
+{
+	driver_unregister(&drv->drv);
+}
+
+static int superhyway_bus_match(struct device *dev, struct device_driver *drv)
+{
+	struct superhyway_device *shyway_dev = to_superhyway_device(dev);
+	struct superhyway_driver *shyway_drv = to_superhyway_driver(drv);
+	const struct superhyway_device_id *ids = shyway_drv->id_table;
+
+	if (!ids)
+		return -EINVAL;
+	if (superhyway_match_id(ids, shyway_dev))
+		return 1;
+
+	return -ENODEV;
+}
+
+struct bus_type superhyway_bus_type = {
+	.name		= "superhyway",
+	.match		= superhyway_bus_match,
+#ifdef CONFIG_SYSFS
+	.dev_attrs	= superhyway_dev_attrs,
+#endif
+};
+
+static int __init superhyway_bus_init(void)
+{
+	return bus_register(&superhyway_bus_type);
+}
+
+static void __exit superhyway_bus_exit(void)
+{
+	device_unregister(&superhyway_bus_device);
+	bus_unregister(&superhyway_bus_type);
+}
+
+core_initcall(superhyway_bus_init);
+module_exit(superhyway_bus_exit);
+
+EXPORT_SYMBOL(superhyway_bus_type);
+EXPORT_SYMBOL(superhyway_add_device);
+EXPORT_SYMBOL(superhyway_register_driver);
+EXPORT_SYMBOL(superhyway_unregister_driver);
+
+MODULE_LICENSE("GPL");
diff -urN linux-2.6/drivers/sh/superhyway/superhyway-sysfs.c linux-sh64-2.6/drivers/sh/superhyway/superhyway-sysfs.c
--- linux-2.6/drivers/sh/superhyway/superhyway-sysfs.c	1970-01-01 02:00:00.000000000 +0200
+++ linux-sh64-2.6/drivers/sh/superhyway/superhyway-sysfs.c	2005-01-12 14:38:00.443223512 +0200
@@ -0,0 +1,45 @@
+/*
+ * drivers/sh/superhyway/superhyway-sysfs.c
+ *
+ * SuperHyway Bus sysfs interface
+ *
+ * Copyright (C) 2004, 2005  Paul Mundt <lethal@linux-sh.org>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/superhyway.h>
+
+#define superhyway_ro_attr(name, fmt, field)				\
+static ssize_t name##_show(struct device *dev, char *buf)		\
+{									\
+	struct superhyway_device *s = to_superhyway_device(dev);	\
+	return sprintf(buf, fmt, s->field);				\
+}
+
+/* VCR flags */
+superhyway_ro_attr(perr_flags, "0x%02x\n", vcr.perr_flags);
+superhyway_ro_attr(merr_flags, "0x%02x\n", vcr.merr_flags);
+superhyway_ro_attr(mod_vers, "0x%04x\n", vcr.mod_vers);
+superhyway_ro_attr(mod_id, "0x%04x\n", vcr.mod_id);
+superhyway_ro_attr(bot_mb, "0x%02x\n", vcr.bot_mb);
+superhyway_ro_attr(top_mb, "0x%02x\n", vcr.top_mb);
+
+/* Misc */
+superhyway_ro_attr(resource, "0x%08lx\n", resource.start);
+
+struct device_attribute superhyway_dev_attrs[] = {
+	__ATTR_RO(perr_flags),
+	__ATTR_RO(merr_flags),
+	__ATTR_RO(mod_vers),
+	__ATTR_RO(mod_id),
+	__ATTR_RO(bot_mb),
+	__ATTR_RO(top_mb),
+	__ATTR_RO(resource),
+	__ATTR_NULL,
+};
+
--- linux-2.6/include/linux/superhyway.h	2005-01-12 14:43:04.969928416 +0200
+++ linux-sh64-2.6/include/linux/superhyway.h	2005-01-12 14:43:37.278016840 +0200
@@ -0,0 +1,79 @@
+/*
+ * include/linux/superhyway.h
+ *
+ * SuperHyway Bus definitions
+ *
+ * Copyright (C) 2004, 2005  Paul Mundt <lethal@linux-sh.org>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#ifndef __LINUX_SUPERHYWAY_H
+#define __LINUX_SUPERHYWAY_H
+
+#include <linux/device.h>
+
+/*
+ * SuperHyway IDs
+ */
+#define SUPERHYWAY_DEVICE_ID_SH5_DMAC	0x0183
+
+struct vcr_info {
+	u8	perr_flags;	/* P-port Error flags */
+	u8	merr_flags;	/* Module Error flags */
+	u16	mod_vers;	/* Module Version */
+	u16	mod_id;		/* Module ID */
+	u8	bot_mb;		/* Bottom Memory block */
+	u8	top_mb;		/* Top Memory block */
+};
+
+struct superhyway_device_id {
+	unsigned int id;
+	unsigned long driver_data;
+};
+
+struct superhyway_device;
+extern struct bus_type superhyway_bus_type;
+
+struct superhyway_driver {
+	char *name;
+
+	const struct superhyway_device_id *id_table;
+	struct device_driver drv;
+
+	int (*probe)(struct superhyway_device *dev, const struct superhyway_device_id *id);
+	void (*remove)(struct superhyway_device *dev);
+};
+
+#define to_superhyway_driver(d)	container_of((d), struct superhyway_driver, drv)
+
+struct superhyway_device {
+	char name[32];
+
+	struct device dev;
+
+	struct superhyway_device_id id;
+	struct superhyway_driver *drv;
+
+	struct resource resource;
+	struct vcr_info vcr;
+};
+
+#define to_superhyway_device(d)	container_of((d), struct superhyway_device, dev)
+
+#define superhyway_get_drvdata(d)	dev_get_drvdata(&(d)->dev)
+#define superhyway_set_drvdata(d,p)	dev_set_drvdata(&(d)->dev, (p))
+
+extern int superhyway_scan_bus(void);
+
+/* drivers/sh/superhyway/superhyway.c */
+int superhyway_register_driver(struct superhyway_driver *);
+void superhyway_unregister_driver(struct superhyway_driver *);
+int superhyway_add_device(unsigned int, unsigned long, unsigned long long);
+
+/* drivers/sh/superhyway/superhyway-sysfs.c */
+extern struct device_attribute superhyway_dev_attrs[];
+
+#endif /* __LINUX_SUPERHYWAY_H */
+

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