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>

1 files changed, 46 insertions, 0 deletions

diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index 928d11454b7e..7b0b295b2313 100644
--- a/drivers/s390/cio/chsc.c
+++ b/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;