s390x/css: Add an algorithm to find a free chpid
This introduces a function named css_find_free_chpid() to find a
free channel path. Because virtio-ccw device used zero as its
channel path number, it would be sensible to skip the reserved one
and search upwards.
Signed-off-by: Jing Liu <liujbjl@linux.vnet.ibm.com>
Reviewed-by: QingFeng Hao <haoqf@linux.vnet.ibm.com>
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h
index f1f0d7f..e61fa74 100644
--- a/include/hw/s390x/css.h
+++ b/include/hw/s390x/css.h
@@ -28,6 +28,7 @@
#define MAX_CIWS 62
#define VIRTUAL_CSSID 0xfe
+#define VIRTIO_CCW_CHPID 0 /* used by convention */
typedef struct CIW {
uint8_t type;
@@ -115,6 +116,7 @@
void css_subch_assign(uint8_t cssid, uint8_t ssid, uint16_t schid,
uint16_t devno, SubchDev *sch);
void css_sch_build_virtual_schib(SubchDev *sch, uint8_t chpid, uint8_t type);
+unsigned int css_find_free_chpid(uint8_t cssid);
uint16_t css_build_subchannel_id(SubchDev *sch);
void css_reset(void);
void css_reset_sch(SubchDev *sch);
