PCMCIA product id strings -> hashes generation at compilation time? [Was: Re: [patch 14/38] pcmcia: id_table for wavelan_cs]

PCMCIA product id strings -> hashes generation at compilation time? [Was: Re: [patch 14/38] pcmcia: id_table for wavelan_cs]

[Dominik Brodowski]

Andrew, Linus, all,

[note: for detailed code please take a look at 2.6.11-mm2]

Most pcmcia devices are matched to drivers using "product ID strings"
embedded in the devices' Card Information Structures, as "manufactor ID /
card ID" matches are much less reliable. Unfortunately, these strings cannot
be passed to userspace for easy userspace-based loading of appropriate
modules (MODNAME -- hotplug), so my suggestion is to also store crc32 hashes
of the strings in the MODULE_DEVICE_TABLEs, e.g.:

PCMCIA_DEVICE_PROD_ID12("LINKSYS", "E-CARD", 0xf7cb0b07, 0x6701da11),

Only the hashes are stored in "modules.alias", and only the hashes
calculated upon device insertion are passed to userspace.

While having to determine the crc32 hashes is a hassle to device driver 
authors, I do not see a smart way to generate these (or similar) hashes 
automatically at compilation time:
	- the C preprocessor doesn't seem to be smart enough
	- scripts/mod/file2alias.c would need to learn all architectures
	  (and be cross-compilation aware) to relocate/dereference/access
	  strings saved as         
		const char *          prod_id[4];
	  in struct pcmcia_device_id s

To make the life easier for device driver authors,
	- a big warning is put into dmesg if a pcmcia driver is inserted
	  into the kernel and the hash mentioned in PCMCIA_DEVICE_PROD_ID()
	  is incorrect,
	- the hash can easily be calculated in userspace from existing
	  /etc/pcmcia/config files, from inserted PCMCIA cards and and and...,
	- I've added the appropriate hashes for all device matches for 
	  drivers in the base linux kernel.

Even though I'm a bit uncomfortable with this solution, I do not see any
other feasible way. Linus, Andrew, do you agree with this handling despite
all the troubles involved with it? 

	Dominik

Re: PCMCIA product id strings -> hashes generation at compilation time? [Was: Re: [patch 14/38] pcmcia: id_table for wavelan_cs]

[Andrew Morton]

Dominik Brodowski <linux@dominikbrodowski.net> wrote:
>
> Most pcmcia devices are matched to drivers using "product ID strings"
>  embedded in the devices' Card Information Structures, as "manufactor ID /
>  card ID" matches are much less reliable. Unfortunately, these strings cannot
>  be passed to userspace for easy userspace-based loading of appropriate
>  modules (MODNAME -- hotplug), so my suggestion is to also store crc32 hashes
>  of the strings in the MODULE_DEVICE_TABLEs, e.g.:
> 
>  PCMCIA_DEVICE_PROD_ID12("LINKSYS", "E-CARD", 0xf7cb0b07, 0x6701da11),

What is the difficulty in passing these strings via /sbin/hotplug arguments?

> ...
>  To make the life easier for device driver authors,
>  	- a big warning is put into dmesg if a pcmcia driver is inserted
>  	  into the kernel and the hash mentioned in PCMCIA_DEVICE_PROD_ID()
>  	  is incorrect,

As long as the kernel shouts loudly at the driver developer at
development-time, and that shouting mentions a bit of documentation in
Documentation/somewhere, I expect we'll be OK.

Re: PCMCIA product id strings -> hashes generation at compilation time? [Was: Re: [patch 14/38] pcmcia: id_table for wavelan_cs]

[Linus Torvalds]

On Tue, 8 Mar 2005, Dominik Brodowski wrote:
>
>				 Unfortunately, these strings cannot
> be passed to userspace for easy userspace-based loading of appropriate
> modules (MODNAME -- hotplug), so my suggestion is to also store crc32 hashes
> of the strings in the MODULE_DEVICE_TABLEs, e.g.:
> 
> PCMCIA_DEVICE_PROD_ID12("LINKSYS", "E-CARD", 0xf7cb0b07, 0x6701da11),

Hmm.. I'm with Andrew on this one - I'd much rather really pass them to 
user space as strings. We already pass a number of strings as environment 
variables.

In fact, what's wrong with DEVPATH? Which we already expose as the
NAME=xxx environment variable. So if the kboject associated with a device
has has this string associated with its name (which it should), then 
hotplug will automatially pass that as the DEVPATH.

So if you just fill out the kobject name with the product ID's (well, 
with the proper escaping of strange characters, of course), everything 
should just work. No?

		Linus

Re: PCMCIA product id strings -> hashes generation at compilation time? [Was: Re: [patch 14/38] pcmcia: id_table for wavelan_cs]

[Dominik Brodowski]

> Dominik Brodowski <linux@dominikbrodowski.net> wrote:
> >
> > Most pcmcia devices are matched to drivers using "product ID strings"
> >  embedded in the devices' Card Information Structures, as "manufactor ID /
> >  card ID" matches are much less reliable. Unfortunately, these strings cannot
> >  be passed to userspace for easy userspace-based loading of appropriate
> >  modules (MODNAME -- hotplug), so my suggestion is to also store crc32 hashes
> >  of the strings in the MODULE_DEVICE_TABLEs, e.g.:
> > 
> >  PCMCIA_DEVICE_PROD_ID12("LINKSYS", "E-CARD", 0xf7cb0b07, 0x6701da11),
> 
> What is the difficulty in passing these strings via /sbin/hotplug arguments?

The difficulty is that extracting and evaluating them breaks the wonderful 
bus-independent MODNAME implementation for hotplug suggested by Roman Kagan
( http://article.gmane.org/gmane.linux.hotplug.devel/7039 ), and that these
strings may contain spaces and other "strange" characters. The latter may be 
worked around, but the former cannot. /etc/hotplug/pcmcia.agent looks really
clean because of this MODNAME implementation:

#!/bin/sh

cd /etc/hotplug
. ./hotplug.functions

if [ "$ACTION" = "" ]; then
    mesg Bad PCMCIA agent invocation, no action
    exit 1
fi

case $ACTION in

add)
        modprobe $MODNAME

	... work around some exotic buggy PCMCIA hardware ...
...

and I would very much like to avoid breaking the line "modprobe $MODNAME".

On Tue, Mar 08, 2005 at 02:54:57PM -0800, Linus Torvalds wrote:
> 
> 
> On Tue, 8 Mar 2005, Dominik Brodowski wrote:
> >
> >				 Unfortunately, these strings cannot
> > be passed to userspace for easy userspace-based loading of appropriate
> > modules (MODNAME -- hotplug), so my suggestion is to also store crc32 hashes
> > of the strings in the MODULE_DEVICE_TABLEs, e.g.:
> > 
> > PCMCIA_DEVICE_PROD_ID12("LINKSYS", "E-CARD", 0xf7cb0b07, 0x6701da11),
> 
> Hmm.. I'm with Andrew on this one - I'd much rather really pass them to 
> user space as strings. We already pass a number of strings as environment 
> variables.
> 
> In fact, what's wrong with DEVPATH? Which we already expose as the
> NAME=xxx environment variable. So if the kboject associated with a device
> has has this string associated with its name (which it should)
drivers/base/core.c::device_add()
        kobject_set_name(&dev->kobj, "%s", dev->bus_id);
and the bus_id isn't the device's name for common buses.

Nontheless, the strings _are_ exported at DEVPATH/prod_id[1-4], but for the
reasons mentioned above I'd prefer not to use them.


On Tue, Mar 08, 2005 at 12:34:26PM -0800, Andrew Morton wrote:
> > ...
> >  To make the life easier for device driver authors,
> >  	- a big warning is put into dmesg if a pcmcia driver is inserted
> >  	  into the kernel and the hash mentioned in PCMCIA_DEVICE_PROD_ID()
> >  	  is incorrect,
> 
> As long as the kernel shouts loudly at the driver developer at
> development-time, and that shouting mentions a bit of documentation in
> Documentation/somewhere, I expect we'll be OK.

Andrew, please apply this patch on top of 2.6.11-mm2, if you and Linus still
agree:


Add some information useful for PCMCIA device driver authors to
Documentation/pcmcia/, and reference it in dmesg in case of hash mismatches.

Also add a reference to pcmciautils to Documentation/Changes. With recent
changes, you don't need to concern yourself with pcmcia-cs even if you have 
PCMCIA hardware, so the example above the list needed to be adapted as well.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowksi.net>
Index: 2.6.11+/Documentation/Changes
===================================================================
--- 2.6.11+.orig/Documentation/Changes	2005-03-08 23:23:30.000000000 +0100
+++ 2.6.11+/Documentation/Changes	2005-03-08 23:23:33.000000000 +0100
@@ -44,9 +44,9 @@
 
 Again, keep in mind that this list assumes you are already
 functionally running a Linux 2.4 kernel.  Also, not all tools are
-necessary on all systems; obviously, if you don't have any PCMCIA (PC
-Card) hardware, for example, you probably needn't concern yourself
-with pcmcia-cs.
+necessary on all systems; obviously, if you don't have any ISDN
+hardware, for example, you probably needn't concern yourself with 
+isdn4k-utils.
 
 o  Gnu C                  2.95.3                  # gcc --version
 o  Gnu make               3.79.1                  # make --version
@@ -57,6 +57,7 @@
 o  jfsutils               1.1.3                   # fsck.jfs -V
 o  reiserfsprogs          3.6.3                   # reiserfsck -V 2>&1|grep reiserfsprogs
 o  xfsprogs               2.6.0                   # xfs_db -V
+o  pcmciautils            001
 o  pcmcia-cs              3.1.21                  # cardmgr -V
 o  quota-tools            3.09                    # quota -V
 o  PPP                    2.4.0                   # pppd --version
@@ -186,13 +187,20 @@
 work correctly with this version of the XFS kernel code (2.6.0 or
 later is recommended, due to some significant improvements).
 
+PCMCIAutils
+-----------
+
+PCMCIAutils replaces pcmcia-cs (see below). It properly sets up
+PCMCIA sockets at system startup and loads the appropriate modules 
+for 16-bit PCMCIA devices if the kernel is modularized and the hotplug
+subsystem is used.
 
 Pcmcia-cs
 ---------
 
 PCMCIA (PC Card) support is now partially implemented in the main
-kernel source.  Pay attention when you recompile your kernel ;-).
-Also, be sure to upgrade to the latest pcmcia-cs release.
+kernel source. The "pcmciautils" package (see above) replaces pcmcia-cs
+for newest kernels.
 
 Quota-tools
 -----------
@@ -349,9 +357,13 @@
 --------
 o  <ftp://oss.sgi.com/projects/xfs/download/>
 
+Pcmciautils
+-----------
+o  <ftp://ftp.kernel.org/pub/linux/utils/kernel/pcmcia/>
+
 Pcmcia-cs
 ---------
-o  <ftp://pcmcia-cs.sourceforge.net/pub/pcmcia-cs/pcmcia-cs-3.1.21.tar.gz>
+o  <http://pcmcia-cs.sourceforge.net/>
 
 Quota-tools
 ----------
Index: 2.6.11+/Documentation/pcmcia/devicetable.txt
===================================================================
--- 2.6.11+.orig/Documentation/pcmcia/devicetable.txt	2005-03-08 22:41:21.540138608 +0100
+++ 2.6.11+/Documentation/pcmcia/devicetable.txt	2005-03-08 23:57:46.000000000 +0100
@@ -0,0 +1,64 @@
+Matching of PCMCIA devices to drivers is done using one or more of the 
+following criteria:
+
+- manufactor ID
+- card ID
+- product ID strings _and_ hashes of these strings
+- function ID
+- device function (actual and pseudo)
+
+You should use the helpers in include/pcmcia/device_id.h for generating the
+struct pcmcia_device_id[] entries which match devices to drivers.
+
+If you want to match product ID strings, you also need to pass the crc32
+hashes of the string to the macro, e.g. if you want to match the product ID
+string 1, you need to use
+
+PCMCIA_DEVICE_PROD_ID1("some_string", 0x(hash_of_some_string)),
+
+If the hash is incorrect, the kernel will inform you about this in "dmesg"
+upon module initialization, and tell you of the correct hash.
+
+You can determine the hash of the product ID strings by running
+"pcmcia-modalias %n.%m" [%n being replaced with the socket number and %m being
+replaced with the device function] from pcmciautils. It generates a string
+in the following form:
+pcmcia:m0149cC1ABf06pfn00fn00pa725B842DpbF1EFEE84pc0877B627pd00000000
+
+The hex value after "pa" is the hash of product ID string 1, after "pb" for
+string 2 and so on.
+
+Alternatively, you can use this small tool to determine the crc32 hash.
+simply pass the string you want to evaluate as argument to this program,
+e.g. 
+$ ./crc32hash "Dual Speed"
+
+-------------------------------------------------------------------------
+/* crc32hash.c - derived from linux/lib/crc32.c, GNU GPL v2 */
+#include <string.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <stdlib.h>
+
+unsigned int crc32(unsigned char const *p, unsigned int len)
+{
+	int i;
+	unsigned int crc = 0;
+	while (len--)
+		crc ^= *p++;
+		for (i = 0; i < 8; i++)
+			crc = (crc >> 1) ^ ((crc & 1) ? 0xedb88320 : 0);
+	}
+	return crc;
+}
+
+int main(int argc, char **argv) {
+	unsigned int result;
+	if (argc != 2) {
+		printf("no string passed as argument\n");
+		return -1;
+	}
+	result = crc32(argv[1], strlen(argv[1]));
+	printf("0x%x\n", result);
+	return 0;
+}
Index: 2.6.11+/Documentation/pcmcia/driver-changes.txt
===================================================================
--- 2.6.11+.orig/Documentation/pcmcia/driver-changes.txt	2005-03-08 22:41:21.540138608 +0100
+++ 2.6.11+/Documentation/pcmcia/driver-changes.txt	2005-03-09 00:01:07.000000000 +0100
@@ -0,0 +1,51 @@
+This file details changes in 2.6 which affect PCMCIA card driver authors:
+
+* in-kernel device<->driver matching
+   PCMCIA devices and their correct drivers can now be matched in
+   kernelspace. See 'devicetable.txt' for details.
+
+* Device model integration (as of 2.6.11)
+   A struct pcmcia_device is registered with the device model core,
+   and can be used (e.g. for SET_NETDEV_DEV) by using
+   handle_to_dev(client_handle_t * handle).
+
+* Convert internal I/O port addresses to unsigned long (as of 2.6.11)
+   ioaddr_t should be replaced by kio_addr_t in PCMCIA card drivers.
+
+* irq_mask and irq_list parameters (as of 2.6.11)
+   The irq_mask and irq_list parameters should no longer be used in
+   PCMCIA card drivers. Instead, it is the job of the PCMCIA core to
+   determine which IRQ should be used. Therefore, link->irq.IRQInfo2
+   is ignored.
+
+* client->PendingEvents is gone (as of 2.6.11)
+   client->PendingEvents is no longer available.
+
+* client->Attributes are gone (as of 2.6.11)
+   client->Attributes is unused, therefore it is removed from all
+   PCMCIA card drivers
+
+* core functions no longer available (as of 2.6.11)
+   The following functions have been removed from the kernel source
+   because they are unused by all in-kernel drivers, and no external
+   driver was reported to rely on them:
+	pcmcia_get_first_region()
+	pcmcia_get_next_region()
+	pcmcia_modify_window()
+	pcmcia_set_event_mask()
+	pcmcia_get_first_window()
+	pcmcia_get_next_window()
+
+* device list iteration upon module removal (as of 2.6.10)
+   It is no longer necessary to iterate on the driver's internal
+   client list and call the ->detach() function upon module removal.
+
+* Resource management. (as of 2.6.8)
+   Although the PCMCIA subsystem will allocate resources for cards,
+   it no longer marks these resources busy. This means that driver
+   authors are now responsible for claiming your resources as per
+   other drivers in Linux. You should use request_region() to mark
+   your IO regions in-use, and request_mem_region() to mark your
+   memory regions in-use. The name argument should be a pointer to
+   your driver name. Eg, for pcnet_cs, name should point to the
+   string "pcnet_cs".
Index: 2.6.11+/drivers/pcmcia/ds.c
===================================================================
--- 2.6.11+.orig/drivers/pcmcia/ds.c	2005-03-08 23:23:30.000000000 +0100
+++ 2.6.11+/drivers/pcmcia/ds.c	2005-03-08 23:59:01.000000000 +0100
@@ -262,8 +262,6 @@
 }
 EXPORT_SYMBOL(cs_error);
 
-#ifdef CONFIG_PCMCIA_DEBUG
-
 
 static void pcmcia_check_driver(struct pcmcia_driver *p_drv)
 {
@@ -284,6 +282,9 @@
 			       "product string \"%s\": is 0x%x, should "
 			       "be 0x%x\n", p_drv->drv.name, did->prod_id[i],
 			       did->prod_id_hash[i], hash);
+			printk(KERN_DEBUG "pcmcia: see "
+				"Documentation/pcmcia/devicetable.txt for "
+				"details\n");
 		}
 		did++;
 	}
@@ -291,12 +292,6 @@
 	return;
 }
 
-#else
-static inline void pcmcia_check_driver(struct pcmcia_driver *p_drv) {
-	return;
-}
-#endif
-
 
 #ifdef CONFIG_PCMCIA_LOAD_CIS
 

Re: PCMCIA product id strings -> hashes generation at compilation time? [Was: Re: [patch 14/38] pcmcia: id_table for wavelan_cs]

[Greg KH]

On Wed, Mar 09, 2005 at 12:16:36AM +0100, Dominik Brodowski wrote:
> > Dominik Brodowski <linux@dominikbrodowski.net> wrote:
> > >
> > > Most pcmcia devices are matched to drivers using "product ID strings"
> > >  embedded in the devices' Card Information Structures, as "manufactor ID /
> > >  card ID" matches are much less reliable. Unfortunately, these strings cannot
> > >  be passed to userspace for easy userspace-based loading of appropriate
> > >  modules (MODNAME -- hotplug), so my suggestion is to also store crc32 hashes
> > >  of the strings in the MODULE_DEVICE_TABLEs, e.g.:
> > > 
> > >  PCMCIA_DEVICE_PROD_ID12("LINKSYS", "E-CARD", 0xf7cb0b07, 0x6701da11),
> > 
> > What is the difficulty in passing these strings via /sbin/hotplug arguments?
> 
> The difficulty is that extracting and evaluating them breaks the wonderful 
> bus-independent MODNAME implementation for hotplug suggested by Roman Kagan
> ( http://article.gmane.org/gmane.linux.hotplug.devel/7039 ), and that these
> strings may contain spaces and other "strange" characters. The latter may be 
> worked around, but the former cannot. /etc/hotplug/pcmcia.agent looks really
> clean because of this MODNAME implementation:

I think that MODNAME should be replaced with MODALIAS, but that's a
different email thread...

Anyway, hashes are icky, I still don't see why using the string as
module aliases, and fixing up modprobe to handle spaces in module
aliases wouldn't work out easier.

thanks,

greg k-h

Re: PCMCIA product id strings -> hashes generation at compilation time? [Was: Re: [patch 14/38] pcmcia: id_table for wavelan_cs]

[Dominik Brodowski]

On Wed, Mar 09, 2005 at 12:16:36AM +0100, Dominik Brodowski wrote:
> > Dominik Brodowski <linux@dominikbrodowski.net> wrote:
> > >
> > > Most pcmcia devices are matched to drivers using "product ID strings"
> > >  embedded in the devices' Card Information Structures, as "manufactor ID /
> > >  card ID" matches are much less reliable. Unfortunately, these strings cannot
> > >  be passed to userspace for easy userspace-based loading of appropriate
> > >  modules (MODNAME -- hotplug), so my suggestion is to also store crc32 hashes
> > >  of the strings in the MODULE_DEVICE_TABLEs, e.g.:
> > > 
> > >  PCMCIA_DEVICE_PROD_ID12("LINKSYS", "E-CARD", 0xf7cb0b07, 0x6701da11),
> > 
> > What is the difficulty in passing these strings via /sbin/hotplug arguments?
> 
> The difficulty is that extracting and evaluating them breaks the wonderful 
> bus-independent MODNAME implementation for hotplug suggested by Roman Kagan
> ( http://article.gmane.org/gmane.linux.hotplug.devel/7039 ), and that these
> strings may contain spaces and other "strange" characters. The latter may be 
> worked around, but the former cannot. /etc/hotplug/pcmcia.agent looks really
> clean because of this MODNAME implementation:

In addition: this isn't the problematic part. The product ID string and/or
the hash can easily be passed from kernelspace to userspace in calls to
hotplug, and that's not the real reason for the hashing. Instead, it is
caused by the module.alias generation (even module.pcmciamap, if it existed,
wouldn't be of help here) at compilation time: the format of such aliases is

alias [bus_name]:[{one or multiple chars as separators}{NUMBERS!} multiple such blocks] [module_name]

This means: only (hex) numbers are allowed as _values_ in such a module alias 
map. The module alias map is generated by file2alias.c, which cannot and
should not be able to access strings inside modules, because that would mean
awareness of all sorts of (arch-dependant) relocation. Therefore,
file2alias.c can't calculate the hashes for us, and as the C preprocessor
cannot either, only the explicit passing of strings _and_ hashes to struct 
pcmcia_device_id-generating macros is the only feasible way I currently see 
to use module.alias for PCMCIA devices.

	Dominik

Re: PCMCIA product id strings -> hashes generation at compilation time? [Was: Re: [patch 14/38] pcmcia: id_table for wavelan_cs]

[Dominik Brodowski]

On Tue, Mar 08, 2005 at 03:37:07PM -0800, Greg KH wrote:
> module aliases, and fixing up modprobe to handle spaces in module
> aliases wouldn't work out easier.

spaces _and_ characters. And characters are already used to separate 
different fields. 

pcmcia:pa"some string"pb"some other string"

doesn't look bad though, indeed. Problem is: how to access the strings in 
file2alias.c? They're in different sections than the __mod_devicetables, and
you'd need to get architecture-dependant relocation... so this doesn't seem 
feasible... or am I missing something?

	Dominik

Re: PCMCIA product id strings -> hashes generation at compilation time? [Was: Re: [patch 14/38] pcmcia: id_table for wavelan_cs]

[Benjamin Herrenschmidt]

On Wed, 2005-03-09 at 00:16 +0100, Dominik Brodowski wrote:
> > Dominik Brodowski <linux@dominikbrodowski.net> wrote:
> > >
> > > Most pcmcia devices are matched to drivers using "product ID strings"
> > >  embedded in the devices' Card Information Structures, as "manufactor ID /
> > >  card ID" matches are much less reliable. Unfortunately, these strings cannot
> > >  be passed to userspace for easy userspace-based loading of appropriate
> > >  modules (MODNAME -- hotplug), so my suggestion is to also store crc32 hashes
> > >  of the strings in the MODULE_DEVICE_TABLEs, e.g.:
> > > 
> > >  PCMCIA_DEVICE_PROD_ID12("LINKSYS", "E-CARD", 0xf7cb0b07, 0x6701da11),
> > 
> > What is the difficulty in passing these strings via /sbin/hotplug arguments?
> 
> The difficulty is that extracting and evaluating them breaks the wonderful 
> bus-independent MODNAME implementation for hotplug suggested by Roman Kagan
> ( http://article.gmane.org/gmane.linux.hotplug.devel/7039 ), and that these
> strings may contain spaces and other "strange" characters. The latter may be 
> worked around, but the former cannot. /etc/hotplug/pcmcia.agent looks really
> clean because of this MODNAME implementation:

Same goes with Open Firmware match strings that we are about to pass
down to userspace as well. Hotplug will have to learn to deal with
those.

> #!/bin/sh
> 
> cd /etc/hotplug
> . ./hotplug.functions
> 
> if [ "$ACTION" = "" ]; then
>     mesg Bad PCMCIA agent invocation, no action
>     exit 1
> fi
> 
> case $ACTION in
> 
> add)
>         modprobe $MODNAME
> 
> 	... work around some exotic buggy PCMCIA hardware ...
> ...
> 
> and I would very much like to avoid breaking the line "modprobe $MODNAME".
> 
> On Tue, Mar 08, 2005 at 02:54:57PM -0800, Linus Torvalds wrote:
> > 
> > 
> > On Tue, 8 Mar 2005, Dominik Brodowski wrote:
> > >
> > >				 Unfortunately, these strings cannot
> > > be passed to userspace for easy userspace-based loading of appropriate
> > > modules (MODNAME -- hotplug), so my suggestion is to also store crc32 hashes
> > > of the strings in the MODULE_DEVICE_TABLEs, e.g.:
> > > 
> > > PCMCIA_DEVICE_PROD_ID12("LINKSYS", "E-CARD", 0xf7cb0b07, 0x6701da11),
> > 
> > Hmm.. I'm with Andrew on this one - I'd much rather really pass them to 
> > user space as strings. We already pass a number of strings as environment 
> > variables.
> > 
> > In fact, what's wrong with DEVPATH? Which we already expose as the
> > NAME=xxx environment variable. So if the kboject associated with a device
> > has has this string associated with its name (which it should)
> drivers/base/core.c::device_add()
>         kobject_set_name(&dev->kobj, "%s", dev->bus_id);
> and the bus_id isn't the device's name for common buses.
> 
> Nontheless, the strings _are_ exported at DEVPATH/prod_id[1-4], but for the
> reasons mentioned above I'd prefer not to use them.
> 
> 
> On Tue, Mar 08, 2005 at 12:34:26PM -0800, Andrew Morton wrote:
> > > ...
> > >  To make the life easier for device driver authors,
> > >  	- a big warning is put into dmesg if a pcmcia driver is inserted
> > >  	  into the kernel and the hash mentioned in PCMCIA_DEVICE_PROD_ID()
> > >  	  is incorrect,
> > 
> > As long as the kernel shouts loudly at the driver developer at
> > development-time, and that shouting mentions a bit of documentation in
> > Documentation/somewhere, I expect we'll be OK.
> 
> Andrew, please apply this patch on top of 2.6.11-mm2, if you and Linus still
> agree:
> 
> 
> Add some information useful for PCMCIA device driver authors to
> Documentation/pcmcia/, and reference it in dmesg in case of hash mismatches.
> 
> Also add a reference to pcmciautils to Documentation/Changes. With recent
> changes, you don't need to concern yourself with pcmcia-cs even if you have 
> PCMCIA hardware, so the example above the list needed to be adapted as well.
> 
> Signed-off-by: Dominik Brodowski <linux@dominikbrodowksi.net>
> Index: 2.6.11+/Documentation/Changes
> ===================================================================
> --- 2.6.11+.orig/Documentation/Changes	2005-03-08 23:23:30.000000000 +0100
> +++ 2.6.11+/Documentation/Changes	2005-03-08 23:23:33.000000000 +0100
> @@ -44,9 +44,9 @@
>  
>  Again, keep in mind that this list assumes you are already
>  functionally running a Linux 2.4 kernel.  Also, not all tools are
> -necessary on all systems; obviously, if you don't have any PCMCIA (PC
> -Card) hardware, for example, you probably needn't concern yourself
> -with pcmcia-cs.
> +necessary on all systems; obviously, if you don't have any ISDN
> +hardware, for example, you probably needn't concern yourself with 
> +isdn4k-utils.
>  
>  o  Gnu C                  2.95.3                  # gcc --version
>  o  Gnu make               3.79.1                  # make --version
> @@ -57,6 +57,7 @@
>  o  jfsutils               1.1.3                   # fsck.jfs -V
>  o  reiserfsprogs          3.6.3                   # reiserfsck -V 2>&1|grep reiserfsprogs
>  o  xfsprogs               2.6.0                   # xfs_db -V
> +o  pcmciautils            001
>  o  pcmcia-cs              3.1.21                  # cardmgr -V
>  o  quota-tools            3.09                    # quota -V
>  o  PPP                    2.4.0                   # pppd --version
> @@ -186,13 +187,20 @@
>  work correctly with this version of the XFS kernel code (2.6.0 or
>  later is recommended, due to some significant improvements).
>  
> +PCMCIAutils
> +-----------
> +
> +PCMCIAutils replaces pcmcia-cs (see below). It properly sets up
> +PCMCIA sockets at system startup and loads the appropriate modules 
> +for 16-bit PCMCIA devices if the kernel is modularized and the hotplug
> +subsystem is used.
>  
>  Pcmcia-cs
>  ---------
>  
>  PCMCIA (PC Card) support is now partially implemented in the main
> -kernel source.  Pay attention when you recompile your kernel ;-).
> -Also, be sure to upgrade to the latest pcmcia-cs release.
> +kernel source. The "pcmciautils" package (see above) replaces pcmcia-cs
> +for newest kernels.
>  
>  Quota-tools
>  -----------
> @@ -349,9 +357,13 @@
>  --------
>  o  <ftp://oss.sgi.com/projects/xfs/download/>
>  
> +Pcmciautils
> +-----------
> +o  <ftp://ftp.kernel.org/pub/linux/utils/kernel/pcmcia/>
> +
>  Pcmcia-cs
>  ---------
> -o  <ftp://pcmcia-cs.sourceforge.net/pub/pcmcia-cs/pcmcia-cs-3.1.21.tar.gz>
> +o  <http://pcmcia-cs.sourceforge.net/>
>  
>  Quota-tools
>  ----------
> Index: 2.6.11+/Documentation/pcmcia/devicetable.txt
> ===================================================================
> --- 2.6.11+.orig/Documentation/pcmcia/devicetable.txt	2005-03-08 22:41:21.540138608 +0100
> +++ 2.6.11+/Documentation/pcmcia/devicetable.txt	2005-03-08 23:57:46.000000000 +0100
> @@ -0,0 +1,64 @@
> +Matching of PCMCIA devices to drivers is done using one or more of the 
> +following criteria:
> +
> +- manufactor ID
> +- card ID
> +- product ID strings _and_ hashes of these strings
> +- function ID
> +- device function (actual and pseudo)
> +
> +You should use the helpers in include/pcmcia/device_id.h for generating the
> +struct pcmcia_device_id[] entries which match devices to drivers.
> +
> +If you want to match product ID strings, you also need to pass the crc32
> +hashes of the string to the macro, e.g. if you want to match the product ID
> +string 1, you need to use
> +
> +PCMCIA_DEVICE_PROD_ID1("some_string", 0x(hash_of_some_string)),
> +
> +If the hash is incorrect, the kernel will inform you about this in "dmesg"
> +upon module initialization, and tell you of the correct hash.
> +
> +You can determine the hash of the product ID strings by running
> +"pcmcia-modalias %n.%m" [%n being replaced with the socket number and %m being
> +replaced with the device function] from pcmciautils. It generates a string
> +in the following form:
> +pcmcia:m0149cC1ABf06pfn00fn00pa725B842DpbF1EFEE84pc0877B627pd00000000
> +
> +The hex value after "pa" is the hash of product ID string 1, after "pb" for
> +string 2 and so on.
> +
> +Alternatively, you can use this small tool to determine the crc32 hash.
> +simply pass the string you want to evaluate as argument to this program,
> +e.g. 
> +$ ./crc32hash "Dual Speed"
> +
> +-------------------------------------------------------------------------
> +/* crc32hash.c - derived from linux/lib/crc32.c, GNU GPL v2 */
> +#include <string.h>
> +#include <stdio.h>
> +#include <ctype.h>
> +#include <stdlib.h>
> +
> +unsigned int crc32(unsigned char const *p, unsigned int len)
> +{
> +	int i;
> +	unsigned int crc = 0;
> +	while (len--)
> +		crc ^= *p++;
> +		for (i = 0; i < 8; i++)
> +			crc = (crc >> 1) ^ ((crc & 1) ? 0xedb88320 : 0);
> +	}
> +	return crc;
> +}
> +
> +int main(int argc, char **argv) {
> +	unsigned int result;
> +	if (argc != 2) {
> +		printf("no string passed as argument\n");
> +		return -1;
> +	}
> +	result = crc32(argv[1], strlen(argv[1]));
> +	printf("0x%x\n", result);
> +	return 0;
> +}
> Index: 2.6.11+/Documentation/pcmcia/driver-changes.txt
> ===================================================================
> --- 2.6.11+.orig/Documentation/pcmcia/driver-changes.txt	2005-03-08 22:41:21.540138608 +0100
> +++ 2.6.11+/Documentation/pcmcia/driver-changes.txt	2005-03-09 00:01:07.000000000 +0100
> @@ -0,0 +1,51 @@
> +This file details changes in 2.6 which affect PCMCIA card driver authors:
> +
> +* in-kernel device<->driver matching
> +   PCMCIA devices and their correct drivers can now be matched in
> +   kernelspace. See 'devicetable.txt' for details.
> +
> +* Device model integration (as of 2.6.11)
> +   A struct pcmcia_device is registered with the device model core,
> +   and can be used (e.g. for SET_NETDEV_DEV) by using
> +   handle_to_dev(client_handle_t * handle).
> +
> +* Convert internal I/O port addresses to unsigned long (as of 2.6.11)
> +   ioaddr_t should be replaced by kio_addr_t in PCMCIA card drivers.
> +
> +* irq_mask and irq_list parameters (as of 2.6.11)
> +   The irq_mask and irq_list parameters should no longer be used in
> +   PCMCIA card drivers. Instead, it is the job of the PCMCIA core to
> +   determine which IRQ should be used. Therefore, link->irq.IRQInfo2
> +   is ignored.
> +
> +* client->PendingEvents is gone (as of 2.6.11)
> +   client->PendingEvents is no longer available.
> +
> +* client->Attributes are gone (as of 2.6.11)
> +   client->Attributes is unused, therefore it is removed from all
> +   PCMCIA card drivers
> +
> +* core functions no longer available (as of 2.6.11)
> +   The following functions have been removed from the kernel source
> +   because they are unused by all in-kernel drivers, and no external
> +   driver was reported to rely on them:
> +	pcmcia_get_first_region()
> +	pcmcia_get_next_region()
> +	pcmcia_modify_window()
> +	pcmcia_set_event_mask()
> +	pcmcia_get_first_window()
> +	pcmcia_get_next_window()
> +
> +* device list iteration upon module removal (as of 2.6.10)
> +   It is no longer necessary to iterate on the driver's internal
> +   client list and call the ->detach() function upon module removal.
> +
> +* Resource management. (as of 2.6.8)
> +   Although the PCMCIA subsystem will allocate resources for cards,
> +   it no longer marks these resources busy. This means that driver
> +   authors are now responsible for claiming your resources as per
> +   other drivers in Linux. You should use request_region() to mark
> +   your IO regions in-use, and request_mem_region() to mark your
> +   memory regions in-use. The name argument should be a pointer to
> +   your driver name. Eg, for pcnet_cs, name should point to the
> +   string "pcnet_cs".
> Index: 2.6.11+/drivers/pcmcia/ds.c
> ===================================================================
> --- 2.6.11+.orig/drivers/pcmcia/ds.c	2005-03-08 23:23:30.000000000 +0100
> +++ 2.6.11+/drivers/pcmcia/ds.c	2005-03-08 23:59:01.000000000 +0100
> @@ -262,8 +262,6 @@
>  }
>  EXPORT_SYMBOL(cs_error);
>  
> -#ifdef CONFIG_PCMCIA_DEBUG
> -
>  
>  static void pcmcia_check_driver(struct pcmcia_driver *p_drv)
>  {
> @@ -284,6 +282,9 @@
>  			       "product string \"%s\": is 0x%x, should "
>  			       "be 0x%x\n", p_drv->drv.name, did->prod_id[i],
>  			       did->prod_id_hash[i], hash);
> +			printk(KERN_DEBUG "pcmcia: see "
> +				"Documentation/pcmcia/devicetable.txt for "
> +				"details\n");
>  		}
>  		did++;
>  	}
> @@ -291,12 +292,6 @@
>  	return;
>  }
>  
> -#else
> -static inline void pcmcia_check_driver(struct pcmcia_driver *p_drv) {
> -	return;
> -}
> -#endif
> -
>  
>  #ifdef CONFIG_PCMCIA_LOAD_CIS
>  
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
-- 
Benjamin Herrenschmidt <benh@kernel.crashing.org>

Re: PCMCIA product id strings -> hashes generation at compilation time? [Was: Re: [patch 14/38] pcmcia: id_table for wavelan_cs]

[Greg KH]

On Wed, Mar 09, 2005 at 04:45:09PM +1100, Benjamin Herrenschmidt wrote:
> On Wed, 2005-03-09 at 00:16 +0100, Dominik Brodowski wrote:
> > > Dominik Brodowski <linux@dominikbrodowski.net> wrote:
> > > >
> > > > Most pcmcia devices are matched to drivers using "product ID strings"
> > > >  embedded in the devices' Card Information Structures, as "manufactor ID /
> > > >  card ID" matches are much less reliable. Unfortunately, these strings cannot
> > > >  be passed to userspace for easy userspace-based loading of appropriate
> > > >  modules (MODNAME -- hotplug), so my suggestion is to also store crc32 hashes
> > > >  of the strings in the MODULE_DEVICE_TABLEs, e.g.:
> > > > 
> > > >  PCMCIA_DEVICE_PROD_ID12("LINKSYS", "E-CARD", 0xf7cb0b07, 0x6701da11),
> > > 
> > > What is the difficulty in passing these strings via /sbin/hotplug arguments?
> > 
> > The difficulty is that extracting and evaluating them breaks the wonderful 
> > bus-independent MODNAME implementation for hotplug suggested by Roman Kagan
> > ( http://article.gmane.org/gmane.linux.hotplug.devel/7039 ), and that these
> > strings may contain spaces and other "strange" characters. The latter may be 
> > worked around, but the former cannot. /etc/hotplug/pcmcia.agent looks really
> > clean because of this MODNAME implementation:
> 
> Same goes with Open Firmware match strings that we are about to pass
> down to userspace as well. Hotplug will have to learn to deal with
> those.

Ok, any suggestions that don't involve hashes?

thanks,

greg k-h

Re: PCMCIA product id strings -> hashes generation at compilation time? [Was: Re: [patch 14/38] pcmcia: id_table for wavelan_cs]

[Dominik Brodowski]

On Wed, Mar 09, 2005 at 04:45:09PM +1100, Benjamin Herrenschmidt wrote:
> On Wed, 2005-03-09 at 00:16 +0100, Dominik Brodowski wrote:
> > > Dominik Brodowski <linux@dominikbrodowski.net> wrote:
> > > >
> > > > Most pcmcia devices are matched to drivers using "product ID strings"
> > > >  embedded in the devices' Card Information Structures, as "manufactor ID /
> > > >  card ID" matches are much less reliable. Unfortunately, these strings cannot
> > > >  be passed to userspace for easy userspace-based loading of appropriate
> > > >  modules (MODNAME -- hotplug), so my suggestion is to also store crc32 hashes
> > > >  of the strings in the MODULE_DEVICE_TABLEs, e.g.:
> > > > 
> > > >  PCMCIA_DEVICE_PROD_ID12("LINKSYS", "E-CARD", 0xf7cb0b07, 0x6701da11),
> > > 
> > > What is the difficulty in passing these strings via /sbin/hotplug arguments?
> > 
> > The difficulty is that extracting and evaluating them breaks the wonderful 
> > bus-independent MODNAME implementation for hotplug suggested by Roman Kagan
> > ( http://article.gmane.org/gmane.linux.hotplug.devel/7039 ), and that these
> > strings may contain spaces and other "strange" characters. The latter may be 
> > worked around, but the former cannot. /etc/hotplug/pcmcia.agent looks really
> > clean because of this MODNAME implementation:
> 
> Same goes with Open Firmware match strings that we are about to pass
> down to userspace as well. Hotplug will have to learn to deal with
> those.

Hotplug isn't the tricky part. file2alias is. Any idea on how to do that?

	Dominik

Re: PCMCIA product id strings -> hashes generation at compilation time? [Was: Re: [patch 14/38] pcmcia: id_table for wavelan_cs]

[Benjamin Herrenschmidt]

> > > The difficulty is that extracting and evaluating them breaks the wonderful 
> > > bus-independent MODNAME implementation for hotplug suggested by Roman Kagan
> > > ( http://article.gmane.org/gmane.linux.hotplug.devel/7039 ), and that these
> > > strings may contain spaces and other "strange" characters. The latter may be 
> > > worked around, but the former cannot. /etc/hotplug/pcmcia.agent looks really
> > > clean because of this MODNAME implementation:
> > 
> > Same goes with Open Firmware match strings that we are about to pass
> > down to userspace as well. Hotplug will have to learn to deal with
> > those.
> 
> Ok, any suggestions that don't involve hashes?

Not sure, I haven't looked at the details & issues involves (I just
"spotted" the issue about space while quick-reading lkml). I suppose
quotes around the strings are good enough, at least for OF, I yet have
to see a "compatible", "name" or "type" property with quotes in it...

Ben.

Re: PCMCIA product id strings -> hashes generation at compilation time? [Was: Re: [patch 14/38] pcmcia: id_table for wavelan_cs]

[Greg KH]

On Wed, Mar 09, 2005 at 08:19:42AM +0100, Dominik Brodowski wrote:
> On Wed, Mar 09, 2005 at 04:45:09PM +1100, Benjamin Herrenschmidt wrote:
> > On Wed, 2005-03-09 at 00:16 +0100, Dominik Brodowski wrote:
> > > > Dominik Brodowski <linux@dominikbrodowski.net> wrote:
> > > > >
> > > > > Most pcmcia devices are matched to drivers using "product ID strings"
> > > > >  embedded in the devices' Card Information Structures, as "manufactor ID /
> > > > >  card ID" matches are much less reliable. Unfortunately, these strings cannot
> > > > >  be passed to userspace for easy userspace-based loading of appropriate
> > > > >  modules (MODNAME -- hotplug), so my suggestion is to also store crc32 hashes
> > > > >  of the strings in the MODULE_DEVICE_TABLEs, e.g.:
> > > > > 
> > > > >  PCMCIA_DEVICE_PROD_ID12("LINKSYS", "E-CARD", 0xf7cb0b07, 0x6701da11),
> > > > 
> > > > What is the difficulty in passing these strings via /sbin/hotplug arguments?
> > > 
> > > The difficulty is that extracting and evaluating them breaks the wonderful 
> > > bus-independent MODNAME implementation for hotplug suggested by Roman Kagan
> > > ( http://article.gmane.org/gmane.linux.hotplug.devel/7039 ), and that these
> > > strings may contain spaces and other "strange" characters. The latter may be 
> > > worked around, but the former cannot. /etc/hotplug/pcmcia.agent looks really
> > > clean because of this MODNAME implementation:
> > 
> > Same goes with Open Firmware match strings that we are about to pass
> > down to userspace as well. Hotplug will have to learn to deal with
> > those.
> 
> Hotplug isn't the tricky part. file2alias is. Any idea on how to do that?

I do not, sorry.  Rusty's the person to bug about that.

good luck,

greg k-h