[RFC] Common header file for FC definitions

[RFC] Common header file for FC definitions

[Christof Schmitt]

zfcp has a couple of definitions to describe the FC protocol. Grepping
through the complete source tree shows that e.g. the lpfc module makes
similar private definitions. It think that it would make sense to
introduce a global header file for FC related definitions that each FC
driver can use.

The attached patch contains some definitons that i found in zfcp and
could be reused by other drivers.

What do others think? Would this be useful?

Christof

---
 include/scsi/fc.h |   47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ b/include/scsi/fc.h	2008-01-08 08:56:32.000000000 +0100
@@ -0,0 +1,47 @@
+/*
+ * Public definitions that are used by Fibre Channel (FC)
+ * device drivers.
+ */
+
+/* FC-PH/FC-GS well-known address identifiers for generic services */
+#define FC_DID_KEY_DISTRIBUTION_SERVICE	0xFFFFF7
+#define FC_DID_ALIAS_SERVICE		0xFFFFF8
+#define FC_DID_MANAGEMENT_SERVICE	0xFFFFFA
+#define FC_DID_TIME_SERVICE		0xFFFFFB
+#define FC_DID_DIRECTORY_SERVICE	0xFFFFFC
+
+#define FC_DID_MASK		      0x00FFFFFF
+
+/* task attribute values in FCP-2 FCP_CMND IU */
+#define SIMPLE_Q	0
+#define HEAD_OF_Q	1
+#define ORDERED_Q	2
+#define ACA_Q		4
+#define UNTAGGED	5
+
+/* task management flags in FCP-2 FCP_CMND IU */
+#define FCP_ABORT_TASK_SET	0x02
+#define FCP_CLEAR_TASK_SET	0x04
+#define FCP_LOGICAL_UNIT_RESET	0x10
+#define FCP_TARGET_RESET	0x20
+#define FCP_CLEAR_ACA		0x40
+
+/* FC-LS */
+#define FC_LS_RLS		0x0f
+#define FC_LS_ADISC		0x52
+#define FC_LS_RPS		0x56
+#define FC_LS_RSCN		0x61
+#define FC_LS_RNID		0x78
+
+/*
+ * FC-GS-2
+ */
+#define FC_CT_REVISION			0x01
+#define FC_CT_DIRECTORY_SERVICE	0xFC
+#define FC_CT_NAME_SERVER		0x02
+#define FC_CT_SYNCHRONOUS		0x00
+#define FC_CT_GID_PN			0x0121
+#define FC_CT_MAX_SIZE			0x1020
+#define FC_CT_ACCEPT			0x8002
+#define FC_CT_REJECT			0x8001
+

Re: [RFC] Common header file for FC definitions

[Christoph Hellwig]

On Tue, Jan 08, 2008 at 09:09:36AM +0100, Christof Schmitt wrote:
> zfcp has a couple of definitions to describe the FC protocol. Grepping
> through the complete source tree shows that e.g. the lpfc module makes
> similar private definitions. It think that it would make sense to
> introduce a global header file for FC related definitions that each FC
> driver can use.
> 
> The attached patch contains some definitons that i found in zfcp and
> could be reused by other drivers.
> 
> What do others think? Would this be useful?

This is a very good idea.  It might make more sense to have the more or
less complete defintions for the fc protocol in the header.  Robert &
folks have been working on a software fc stack part as the fcoe header
so they might have one to contribute.

Re: [RFC] Common header file for FC definitions

[James Smart]

Christoph Hellwig wrote:
> On Tue, Jan 08, 2008 at 09:09:36AM +0100, Christof Schmitt wrote:
>> zfcp has a couple of definitions to describe the FC protocol. Grepping
>> through the complete source tree shows that e.g. the lpfc module makes
>> similar private definitions. It think that it would make sense to
>> introduce a global header file for FC related definitions that each FC
>> driver can use.
>>
>> The attached patch contains some definitons that i found in zfcp and
>> could be reused by other drivers.
>>
>> What do others think? Would this be useful?
> 
> This is a very good idea.  It might make more sense to have the more or
> less complete defintions for the fc protocol in the header.  Robert &
> folks have been working on a software fc stack part as the fcoe header
> so they might have one to contribute.

I Agree - A common header for standard FC definitions would be a good thing.

That said, we have to be a little lenient on when drivers convert over to
the standard headers as there's likely code change required.

-- james s

Re: [RFC] Common header file for FC definitions

[Christof Schmitt]

On Tue, Jan 08, 2008 at 10:46:51AM -0500, James Smart wrote:
> Christoph Hellwig wrote:
> >On Tue, Jan 08, 2008 at 09:09:36AM +0100, Christof Schmitt wrote:
> >>zfcp has a couple of definitions to describe the FC protocol. Grepping
> >>through the complete source tree shows that e.g. the lpfc module makes
> >>similar private definitions. It think that it would make sense to
> >>introduce a global header file for FC related definitions that each FC
> >>driver can use.
> >>
> >>The attached patch contains some definitons that i found in zfcp and
> >>could be reused by other drivers.
> >>
> >>What do others think? Would this be useful?
> >
> >This is a very good idea.  It might make more sense to have the more or
> >less complete defintions for the fc protocol in the header.  Robert &
> >folks have been working on a software fc stack part as the fcoe header
> >so they might have one to contribute.
> 
> I Agree - A common header for standard FC definitions would be a good thing.
> 
> That said, we have to be a little lenient on when drivers convert over to
> the standard headers as there's likely code change required.

For zfcp, i would like to move the FC specific definitions out of the
zfcp_def.h header file. My idea would be to introduce a simple header
file like proposed and to adapt zfcp to use these.  I don't intend to
write header files for the full FC protocol, since zfcp only uses a
small part. When other drivers use more definitions, then the
definitions can be added to the existing file.

When other drivers want to use the global definitions, they can
include the global file, but they don't have to.

Would others also be interested in having structs in the global header
file for FC commands like this?

struct zfcp_ls_adisc {
	u8		code;
	u8		field[3];
	u32		hard_nport_id;
	u64		wwpn;
	u64		wwnn;
	u32		nport_id;
} __attribute__ ((packed));

This could be renamed to fc_ls_adisc and also be part of the global
header file. But probably it makes more sense to start simple now and
think about the common structs later.

Thanks for the comments.

Christof

Re: [RFC] Common header file for FC definitions

[Seokmann Ju]

Christof Schmitt wrote:
> zfcp has a couple of definitions to describe the FC protocol. Grepping
> through the complete source tree shows that e.g. the lpfc module makes
> similar private definitions. It think that it would make sense to
> introduce a global header file for FC related definitions that each FC
> driver can use.
> 
> The attached patch contains some definitons that i found in zfcp and
> could be reused by other drivers.
> 
> What do others think? Would this be useful?
This is good idea. It could be widely used for FC drivers across the vendors as their features get added.
Especially for Link Services including FC-CT protocol.

Thank you,
Seokmann