Commit 6c15e9bf authored by Jing Liu's avatar Jing Liu Committed by Cornelia Huck
Browse files

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: default avatarJing Liu <liujbjl@linux.vnet.ibm.com>
Reviewed-by: default avatarQingFeng Hao <haoqf@linux.vnet.ibm.com>
Reviewed-by: default avatarDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
parent ae92cbd5

hw/s390x/css.c

+21 −0
Original line number Diff line number Diff line
@@ -1302,6 +1302,27 @@ bool css_schid_final(int m, uint8_t cssid, uint8_t ssid, uint16_t schid) 
                                 (MAX_SCHID + 1) / sizeof(unsigned long));

}



unsigned int css_find_free_chpid(uint8_t cssid)

{

    CssImage *css = channel_subsys.css[cssid];

    unsigned int chpid;



    if (!css) {

        return MAX_CHPID + 1;

    }



    for (chpid = 0; chpid <= MAX_CHPID; chpid++) {

        /* skip reserved chpid */

        if (chpid == VIRTIO_CCW_CHPID) {

            continue;

        }

        if (!css->chpids[chpid].in_use) {

            return chpid;

        }

    }

    return MAX_CHPID + 1;

}



static int css_add_virtual_chpid(uint8_t cssid, uint8_t chpid, uint8_t type)

{

    CssImage *css;

include/hw/s390x/css.h

+2 −0
Original line number Diff line number Diff line
@@ -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 @@ bool css_devno_used(uint8_t cssid, uint8_t ssid, uint16_t devno); 
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);