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Subject[PATCH] EISA/sysfs update
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Date
LKML, Linus,

Here is the latest round of EISA/sysfs update.

From the changelog :

# EISA/sysfs update :
# Add documentation,
# Add support for per EISA-id driver data,
# Move virtual_root device to a plateform device,
# Update CREDITS.

Thanks a lot,

M.

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
# ChangeSet 1.1037 -> 1.1038
# drivers/eisa/eisa-bus.c 1.5 -> 1.6
# CREDITS 1.77 -> 1.78
# drivers/eisa/virtual_root.c 1.1 -> 1.2
# include/linux/eisa.h 1.3 -> 1.4
# (new) -> 1.1 Documentation/eisa.txt
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 03/03/05 maz@hina.wild-wind.fr.eu.org 1.1038
# EISA/sysfs update :
# Add documentation,
# Add support for per EISA-id driver data,
# Move virtual_root device to a plateform device,
# Update CREDITS.
# --------------------------------------------
#
diff -Nru a/CREDITS b/CREDITS
--- a/CREDITS Wed Mar 5 15:11:17 2003
+++ b/CREDITS Wed Mar 5 15:11:17 2003
@@ -3492,9 +3492,9 @@

N: Marc Zyngier
E: maz@wild-wind.fr.eu.org
+W: http://www.misterjones.org
D: MD driver
-S: 11 rue Victor HUGO
-S: 95560 Montsoult
+D: EISA/sysfs subsystem
S: France

# Don't add your name here, unless you really _are_ after Marc
diff -Nru a/Documentation/eisa.txt b/Documentation/eisa.txt
--- /dev/null Wed Dec 31 16:00:00 1969
+++ b/Documentation/eisa.txt Wed Mar 5 15:11:17 2003
@@ -0,0 +1,164 @@
+EISA bus support (Marc Zyngier <maz@wild-wind.fr.eu.org>)
+
+This document groups random notes about porting EISA drivers to the
+new EISA/sysfs API.
+
+Starting from version 2.5.59, the EISA bus is almost given the same
+status as other much more mainstream busses such as PCI or USB. This
+has been possible through sysfs, which defines a nice enough set of
+abstractions to manage busses, devices and drivers.
+
+Although the new API is quite simple to use, converting existing
+drivers to the new infrastructure is not an easy task (mostly because
+detection code is generally also used to probe ISA cards). Moreover,
+most EISA drivers are among the oldest Linux drivers so, as you can
+imagine, some dust has settled here over the years.
+
+The EISA infrastructure is made up of three parts :
+
+ - The bus code implements most of the generic code. It is shared
+ among all the architectures that the EISA code runs on. It
+ implements bus probing (detecting EISA cards avaible on the bus),
+ allocates I/O resources, allows fancy naming through sysfs, and
+ offers interfaces for driver to register.
+
+ - The bus root driver implements the glue between the bus hardware
+ and the generic bus code. It is responsible for discovering the
+ device implementing the bus, and setting it up to be latter probed
+ by the bus code. This can go from something as simple as reserving
+ an I/O region on x86, to the rather more complex, like the hppa
+ EISA code. This is the part to implement in order to have EISA
+ running on an "new" platform.
+
+ - The driver offers the bus a list of devices that it manages, and
+ implements the necessary callbacks to probe and release devices
+ whenever told to.
+
+Every function/structure below lives in <linux/eisa.h>, which depends
+heavily on <linux/device.h>.
+
+** Bus root driver :
+
+int eisa_root_register (struct eisa_root_device *root);
+
+The eisa_root_register function is used to declare a device as the
+root of an EISA bus. The eisa_root_device structure holds a reference
+to this device, as well as some parameters for probing purposes.
+
+struct eisa_root_device {
+ struct list_head node;
+ struct device *dev; /* Pointer to bridge device */
+ struct resource *res;
+ unsigned long bus_base_addr;
+ int slots; /* Max slot number */
+ int bus_nr; /* Set by eisa_root_register */
+};
+
+node : used for eisa_root_register internal purpose
+dev : pointer to the root device
+res : root device I/O resource
+bus_base_addr : slot 0 address on this bus
+slots : max slot number to probe
+bus_nr : unique bus id, set by eisa_root_register
+
+** Driver :
+
+int eisa_driver_register (struct eisa_driver *edrv);
+void eisa_driver_unregister (struct eisa_driver *edrv);
+
+Clear enough ?
+
+struct eisa_device_id {
+ char sig[EISA_SIG_LEN];
+ unsigned long driver_data;
+};
+
+struct eisa_driver {
+ const struct eisa_device_id *id_table;
+ struct device_driver driver;
+};
+
+id_table : an array of NULL terminated EISA id strings,
+ followed by an empty string. Each string can be
+ paired with a driver-dependant value (driver_data).
+
+driver : a generic driver, such as described in
+ Documentation/driver-model/driver.txt. Only .name,
+ .probe and .remove members are mandatory.
+
+An example is the 3c509 driver :
+
+struct eisa_device_id el3_eisa_ids[] = {
+ { "TCM5092" },
+ { "TCM5093" },
+ { "" }
+};
+
+struct eisa_driver el3_eisa_driver = {
+ .id_table = el3_eisa_ids,
+ .driver = {
+ .name = "3c509",
+ .probe = el3_eisa_probe,
+ .remove = __devexit_p (el3_device_remove)
+ }
+};
+
+** Device :
+
+The sysfs framework calls .probe and .remove functions upon device
+discovery and removal (note that the .remove function is only called
+when driver is built as a module).
+
+Both functions are passed a pointer to a 'struct device', which is
+encapsulated in a 'struct eisa_device' described as follows :
+
+struct eisa_device {
+ struct eisa_device_id id;
+ int slot;
+ unsigned long base_addr;
+ struct resource res;
+ struct device dev; /* generic device */
+};
+
+id : EISA id, as read from device. id.driver_data is set from the
+ matching driver EISA id.
+slot : slot number which the device was detected on
+res : I/O resource allocated to this device
+dev : generic device (see Documentation/driver-model/device.txt)
+
+You can get the 'struct eisa_device' from 'struct device' using the
+'to_eisa_device' macro.
+
+** Misc stuff :
+
+void eisa_set_drvdata (struct eisa_device *edev, void *data);
+
+Stores data into the device's driver_data area.
+
+void *eisa_get_drvdata (struct eisa_device *edev):
+
+Gets the pointer previously stored into the device's driver_data area.
+
+** Random notes :
+
+Converting an EISA driver to the new API mostly involves *deleting*
+code (since probing is now in the core EISA code). Unfortunately, most
+drivers share their probing routine between ISA, MCA and EISA. Special
+care must be taken when ripping out the EISA code, so other busses
+won't suffer from these surgical strikes...
+
+You *must not* expect any EISA device to be detected when returning
+from eisa_driver_register, since the chances are that the bus has not
+yet been probed. In fact, that's what happens most of the time (the
+bus root driver usually kicks in rather late in the boot process).
+Unfortunately, most drivers are doing the probing by themselves, and
+expect to have explored the whole machine when they exit their probe
+routine.
+
+** Thanks :
+
+I'd like to thank the following people for their help :
+- Xavier Benigni for lending me a wonderful Alpha Jensen,
+- James Bottomley, Jeff Garzik for getting this stuff into the kernel,
+- Andries Brouwer for contributing numerous EISA ids,
+- Catrin Jones for coping with too many machines at home
diff -Nru a/drivers/eisa/eisa-bus.c b/drivers/eisa/eisa-bus.c
--- a/drivers/eisa/eisa-bus.c Wed Mar 5 15:11:17 2003
+++ b/drivers/eisa/eisa-bus.c Wed Mar 5 15:11:17 2003
@@ -83,8 +83,10 @@
return 0;

while (strlen (eids->sig)) {
- if (!strcmp (eids->sig, edev->id.sig))
+ if (!strcmp (eids->sig, edev->id.sig)) {
+ edev->id.driver_data = eids->driver_data;
return 1;
+ }

eids++;
}
diff -Nru a/drivers/eisa/virtual_root.c b/drivers/eisa/virtual_root.c
--- a/drivers/eisa/virtual_root.c Wed Mar 5 15:11:17 2003
+++ b/drivers/eisa/virtual_root.c Wed Mar 5 15:11:17 2003
@@ -13,14 +13,19 @@
#include <linux/module.h>
#include <linux/init.h>

-/* The default EISA device parent (virtual root device). */
-static struct device eisa_root_dev = {
- .name = "Virtual EISA Bridge",
- .bus_id = "eisa",
+/* The default EISA device parent (virtual root device).
+ * Now use a platform device, since that's the obvious choice. */
+
+static struct platform_device eisa_root_dev = {
+ .name = "eisa",
+ .id = 0,
+ .dev = {
+ .name = "Virtual EISA Bridge",
+ },
};

static struct eisa_root_device eisa_bus_root = {
- .dev = &eisa_root_dev,
+ .dev = &eisa_root_dev.dev,
.bus_base_addr = 0,
.res = &ioport_resource,
.slots = EISA_MAX_SLOTS,
@@ -30,16 +35,16 @@
{
int r;

- if ((r = device_register (&eisa_root_dev))) {
+ if ((r = platform_device_register (&eisa_root_dev))) {
return r;
}

- eisa_root_dev.driver_data = &eisa_bus_root;
+ eisa_root_dev.dev.driver_data = &eisa_bus_root;

if (eisa_root_register (&eisa_bus_root)) {
/* A real bridge may have been registered before
* us. So quietly unregister. */
- device_unregister (&eisa_root_dev);
+ platform_device_unregister (&eisa_root_dev);
return -1;
}

diff -Nru a/include/linux/eisa.h b/include/linux/eisa.h
--- a/include/linux/eisa.h Wed Mar 5 15:11:17 2003
+++ b/include/linux/eisa.h Wed Mar 5 15:11:17 2003
@@ -20,7 +20,8 @@

/* The EISA signature, in ASCII form, null terminated */
struct eisa_device_id {
- char sig[EISA_SIG_LEN];
+ char sig[EISA_SIG_LEN];
+ unsigned long driver_data;
};

/* There is not much we can say about an EISA device, apart from--
Places change, faces change. Life is so very strange.
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