[S390] cio: Add chsc subchannel driver.

This patch adds a driver for subchannels of type chsc.

A device /dev/chsc is created which may be used to issue ioctls to:
- obtain information about the machine's I/O configuration
- dynamically change the machine's I/O configuration via
  asynchronous chsc commands

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

Documentation/ioctl-number.txt

@@ -117,6 +117,7 @@ Code	Seq#	Include File		Comments
 					<mailto:natalia@nikhefk.nikhef.nl>
 'c'	00-7F	linux/comstats.h	conflict!
 'c'	00-7F	linux/coda.h		conflict!
+'c'	80-9F	asm-s390/chsc.h
 'd'	00-FF	linux/char/drm/drm/h	conflict!
 'd'	00-DF	linux/video_decoder.h	conflict!
 'd'	F0-FF	linux/digi1.h

arch/s390/Kconfig

@@ -345,6 +345,22 @@ config QDIO_DEBUG
 
 	  If unsure, say N.
 
+config CHSC_SCH
+	tristate "Support for CHSC subchannels"
+	help
+	  This driver allows usage of CHSC subchannels. A CHSC subchannel
+	  is usually present on LPAR only.
+	  The driver creates a device /dev/chsc, which may be used to
+	  obtain I/O configuration information about the machine and
+	  to issue asynchronous chsc commands (DANGEROUS).
+	  You will usually only want to use this interface on a special
+	  LPAR designated for system management.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called chsc_sch.
+
+	  If unsure, say N.
+
 comment "Misc"
 
 config IPL

drivers/s390/cio/Makefile

@@ -7,5 +7,6 @@ obj-y += airq.o blacklist.o chsc.o cio.o css.o chp.o idset.o isc.o scsw.o \
 ccw_device-objs += device.o device_fsm.o device_ops.o
 ccw_device-objs += device_id.o device_pgid.o device_status.o
 obj-y += ccw_device.o cmf.o
+obj-$(CONFIG_CHSC_SCH) += chsc_sch.o
 obj-$(CONFIG_CCWGROUP) += ccwgroup.o
 obj-$(CONFIG_QDIO) += qdio.o

drivers/s390/cio/chp.c

@@ -407,7 +407,7 @@ int chp_new(struct chp_id chpid)
 		 chpid.id);
 
 	/* Obtain channel path description and fill it in. */
-	ret = chsc_determine_channel_path_description(chpid, &chp->desc);
+	ret = chsc_determine_base_channel_path_desc(chpid, &chp->desc);
 	if (ret)
 		goto out_free;
 	if ((chp->desc.flags & 0x80) == 0) {

drivers/s390/cio/chsc.c

@@ -15,6 +15,7 @@
 
 #include <asm/cio.h>
 #include <asm/chpid.h>
+#include <asm/chsc.h>
 
 #include "../s390mach.h"
 #include "css.h"
@@ -627,32 +628,47 @@ chsc_secm(struct channel_subsystem *css, int enable)
 	return ret;
 }
 
-int chsc_determine_channel_path_description(struct chp_id chpid,
-					    struct channel_path_desc *desc)
+int chsc_determine_channel_path_desc(struct chp_id chpid, int fmt, int rfmt,
+				     int c, int m,
+				     struct chsc_response_struct *resp)
 {
 	int ccode, ret;
 
 	struct {
 		struct chsc_header request;
-		u32 : 24;
+		u32 : 2;
+		u32 m : 1;
+		u32 c : 1;
+		u32 fmt : 4;
+		u32 cssid : 8;
+		u32 : 4;
+		u32 rfmt : 4;
 		u32 first_chpid : 8;
 		u32 : 24;
 		u32 last_chpid : 8;
 		u32 zeroes1;
 		struct chsc_header response;
-		u32 zeroes2;
-		struct channel_path_desc desc;
+		u8 data[PAGE_SIZE - 20];
 	} __attribute__ ((packed)) *scpd_area;
 
+	if ((rfmt == 1) && !css_general_characteristics.fcs)
+		return -EINVAL;
+	if ((rfmt == 2) && !css_general_characteristics.cib)
+		return -EINVAL;
 	scpd_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
 	if (!scpd_area)
 		return -ENOMEM;
 
 	scpd_area->request.length = 0x0010;
 	scpd_area->request.code = 0x0002;
 
+	scpd_area->cssid = chpid.cssid;
 	scpd_area->first_chpid = chpid.id;
 	scpd_area->last_chpid = chpid.id;
+	scpd_area->m = m;
+	scpd_area->c = c;
+	scpd_area->fmt = fmt;
+	scpd_area->rfmt = rfmt;
 
 	ccode = chsc(scpd_area);
 	if (ccode > 0) {
@@ -663,15 +679,33 @@ int chsc_determine_channel_path_description(struct chp_id chpid,
 	ret = chsc_error_from_response(scpd_area->response.code);
 	if (ret == 0)
 		/* Success. */
-		memcpy(desc, &scpd_area->desc,
-		       sizeof(struct channel_path_desc));
+		memcpy(resp, &scpd_area->response, scpd_area->response.length);
 	else
 		CIO_CRW_EVENT(2, "chsc: scpd failed (rc=%04x)\n",
 			      scpd_area->response.code);
 out:
 	free_page((unsigned long)scpd_area);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(chsc_determine_channel_path_desc);
+
+int chsc_determine_base_channel_path_desc(struct chp_id chpid,
+					  struct channel_path_desc *desc)
+{
+	struct chsc_response_struct *chsc_resp;
+	int ret;
+
+	chsc_resp = kzalloc(sizeof(*chsc_resp), GFP_KERNEL);
+	if (!chsc_resp)
+		return -ENOMEM;
+	ret = chsc_determine_channel_path_desc(chpid, 0, 0, 0, 0, chsc_resp);
+	if (ret)
+		goto out_free;
+	memcpy(desc, &chsc_resp->data, chsc_resp->length);
+out_free:
+	kfree(chsc_resp);
+	return ret;
+}
 
 static void
 chsc_initialize_cmg_chars(struct channel_path *chp, u8 cmcv,

drivers/s390/cio/chsc.h

@@ -4,7 +4,8 @@
 #include <linux/types.h>
 #include <linux/device.h>
 #include <asm/chpid.h>
-#include "schid.h"
+#include <asm/chsc.h>
+#include <asm/schid.h>
 
 #define CHSC_SDA_OC_MSS   0x2
 
@@ -37,19 +38,24 @@ struct channel_path_desc {
 struct channel_path;
 
 struct css_general_char {
-	u64 : 41;
+	u64 : 12;
+	u32 dynio : 1;	 /* bit 12 */
+	u32 : 28;
 	u32 aif : 1;     /* bit 41 */
 	u32 : 3;
 	u32 mcss : 1;    /* bit 45 */
-	u32 : 2;
+	u32 fcs : 1;	 /* bit 46 */
+	u32 : 1;
 	u32 ext_mb : 1;  /* bit 48 */
 	u32 : 7;
 	u32 aif_tdd : 1; /* bit 56 */
 	u32 : 1;
 	u32 qebsm : 1;   /* bit 58 */
 	u32 : 8;
 	u32 aif_osa : 1; /* bit 67 */
-	u32 : 20;
+	u32 : 14;
+	u32 cib : 1;	 /* bit 82 */
+	u32 : 5;
 	u32 fcx : 1;	 /* bit 88 */
 	u32 : 7;
 }__attribute__((packed));
@@ -86,8 +92,11 @@ struct channel_subsystem;
 extern int chsc_secm(struct channel_subsystem *, int);
 
 int chsc_chp_vary(struct chp_id chpid, int on);
-int chsc_determine_channel_path_description(struct chp_id chpid,
-					    struct channel_path_desc *desc);
+int chsc_determine_channel_path_desc(struct chp_id chpid, int fmt, int rfmt,
+				     int c, int m,
+				     struct chsc_response_struct *resp);
+int chsc_determine_base_channel_path_desc(struct chp_id chpid,
+					  struct channel_path_desc *desc);
 void chsc_chp_online(struct chp_id chpid);
 void chsc_chp_offline(struct chp_id chpid);
 int chsc_get_channel_measurement_chars(struct channel_path *chp);