s390/cio: use cssid for pgid generation

Obtain the real channel subsystem id and use that for the generation
of a unique path group id. Note that this change does not affect the
channel subsystem id as used in the user-visible naming of subchannels
and friends.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Dong Jia Shi <bjsdjshik@linux.vnet.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/chsc.c

@@ -1131,6 +1131,52 @@ int chsc_enable_facility(int operation_code)
 	return ret;
 }
 
+int __init chsc_get_cssid(int idx)
+{
+	struct {
+		struct chsc_header request;
+		u8 atype;
+		u32 : 24;
+		u32 reserved1[6];
+		struct chsc_header response;
+		u32 reserved2[3];
+		struct {
+			u8 cssid;
+			u32 : 24;
+		} list[0];
+	} __packed *sdcal_area;
+	int ret;
+
+	spin_lock_irq(&chsc_page_lock);
+	memset(chsc_page, 0, PAGE_SIZE);
+	sdcal_area = chsc_page;
+	sdcal_area->request.length = 0x0020;
+	sdcal_area->request.code = 0x0034;
+	sdcal_area->atype = 4;
+
+	ret = chsc(sdcal_area);
+	if (ret) {
+		ret = (ret == 3) ? -ENODEV : -EBUSY;
+		goto exit;
+	}
+
+	ret = chsc_error_from_response(sdcal_area->response.code);
+	if (ret) {
+		CIO_CRW_EVENT(2, "chsc: sdcal failed (rc=%04x)\n",
+			      sdcal_area->response.code);
+		goto exit;
+	}
+
+	if ((addr_t) &sdcal_area->list[idx] <
+	    (addr_t) &sdcal_area->response + sdcal_area->response.length)
+		ret = sdcal_area->list[idx].cssid;
+	else
+		ret = -ENODEV;
+exit:
+	spin_unlock_irq(&chsc_page_lock);
+	return ret;
+}
+
 struct css_general_char css_general_characteristics;
 struct css_chsc_char css_chsc_characteristics;
 

drivers/s390/cio/chsc.h

@@ -242,6 +242,8 @@ int chsc_pnso_brinfo(struct subchannel_id schid,
 		struct chsc_brinfo_resume_token resume_token,
 		int cnc);
 
+int __init chsc_get_cssid(int idx);
+
 #ifdef CONFIG_SCM_BUS
 int scm_update_information(void);
 int scm_process_availability_information(void);

drivers/s390/cio/css.c

@@ -703,7 +703,8 @@ css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 
 	if (css_general_characteristics.mcss) {
 		css->global_pgid.pgid_high.ext_cssid.version = 0x80;
-		css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
+		css->global_pgid.pgid_high.ext_cssid.cssid =
+			(css->cssid < 0) ? 0 : css->cssid;
 	} else {
 		css->global_pgid.pgid_high.cpu_addr = stap();
 	}
@@ -794,7 +795,8 @@ static int __init setup_css(int nr)
 	}
 	mutex_init(&css->mutex);
 	css->valid = 1;
-	css->cssid = nr;
+	css->cssid = chsc_get_cssid(nr);
+
 	dev_set_name(&css->device, "css%x", nr);
 	css->device.release = channel_subsystem_release;
 	tod_high = (u32) (get_tod_clock() >> 32);

drivers/s390/cio/css.h

@@ -113,7 +113,7 @@ extern int for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *);
 void css_update_ssd_info(struct subchannel *sch);
 
 struct channel_subsystem {
-	u8 cssid;
+	int cssid;
 	int valid;
 	struct channel_path *chps[__MAX_CHPID + 1];
 	struct device device;