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/*
* S390 Channel I/O
*
* Copyright (c) 2013 Alexander Graf <agraf@suse.de>
* Copyright (c) 2019 IBM Corp.
*
* Author(s): Jason J. Herne <jjherne@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or (at
* your option) any later version. See the COPYING file in the top-level
* directory.
*/
#include "libc.h"
#include "s390-ccw.h"
#include "s390-arch.h"
#include "helper.h"
#include "cio.h"
static char chsc_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
static int __do_cio(SubChannelId schid, uint32_t ccw_addr, int fmt, Irb *irb);
int enable_mss_facility(void)
{
int ret;
ChscAreaSda *sda_area = (ChscAreaSda *) chsc_page;
memset(sda_area, 0, PAGE_SIZE);
sda_area->request.length = 0x0400;
sda_area->request.code = 0x0031;
sda_area->operation_code = 0x2;
ret = chsc(sda_area);
if ((ret == 0) && (sda_area->response.code == 0x0001)) {
return 0;
}
return -EIO;
}
void enable_subchannel(SubChannelId schid)
{
Schib schib;
stsch_err(schid, &schib);
schib.pmcw.ena = 1;
msch(schid, &schib);
}
uint16_t cu_type(SubChannelId schid)
{
Ccw1 sense_id_ccw;
SenseId sense_data;
sense_id_ccw.cmd_code = CCW_CMD_SENSE_ID;
sense_id_ccw.cda = ptr2u32(&sense_data);
sense_id_ccw.count = sizeof(sense_data);
sense_id_ccw.flags |= CCW_FLAG_SLI;
if (do_cio(schid, CU_TYPE_UNKNOWN, ptr2u32(&sense_id_ccw), CCW_FMT1)) {
panic("Failed to run SenseID CCw\n");
}
return sense_data.cu_type;
}
int basic_sense(SubChannelId schid, uint16_t cutype, void *sense_data,
uint16_t data_size)
{
Ccw1 senseCcw;
Irb irb;
senseCcw.cmd_code = CCW_CMD_BASIC_SENSE;
senseCcw.cda = ptr2u32(sense_data);
senseCcw.count = data_size;
return __do_cio(schid, ptr2u32(&senseCcw), CCW_FMT1, &irb);
}
static bool irb_error(Irb *irb)
{
if (irb->scsw.cstat) {
return true;
}
return irb->scsw.dstat != (SCSW_DSTAT_DEVEND | SCSW_DSTAT_CHEND);
}
/*
* Handles executing ssch, tsch and returns the irb obtained from tsch.
* Returns 0 on success, -1 if unexpected status pending and we need to retry,
* otherwise returns condition code from ssch/tsch for error cases.
*/
static int __do_cio(SubChannelId schid, uint32_t ccw_addr, int fmt, Irb *irb)
{
CmdOrb orb = {};
int rc;
IPL_assert(fmt == 0 || fmt == 1, "Invalid ccw format");
/* ccw_addr must be <= 24 bits and point to at least one whole ccw. */
if (fmt == 0) {
IPL_assert(ccw_addr <= 0xFFFFFF - 8, "Invalid ccw address");
}
orb.fmt = fmt;
orb.pfch = 1; /* QEMU's cio implementation requires prefetch */
orb.c64 = 1; /* QEMU's cio implementation requires 64-bit idaws */
orb.lpm = 0xFF; /* All paths allowed */
orb.cpa = ccw_addr;
rc = ssch(schid, &orb);
if (rc == 1 || rc == 2) {
/* Subchannel status pending or busy. Eat status and ask for retry. */
tsch(schid, irb);
return -1;
}
if (rc) {
print_int("ssch failed with cc=", rc);
return rc;
}
consume_io_int();
/* collect status */
rc = tsch(schid, irb);
if (rc) {
print_int("tsch failed with cc=", rc);
}
return rc;
}
/*
* Executes a channel program at a given subchannel. The request to run the
* channel program is sent to the subchannel, we then wait for the interrupt
* signaling completion of the I/O operation(s) performed by the channel
* program. Lastly we verify that the i/o operation completed without error and
* that the interrupt we received was for the subchannel used to run the
* channel program.
*
* Note: This function assumes it is running in an environment where no other
* cpus are generating or receiving I/O interrupts. So either run it in a
* single-cpu environment or make sure all other cpus are not doing I/O and
* have I/O interrupts masked off. We also assume that only one device is
* active (generating i/o interrupts).
*
* Returns non-zero on error.
*/
int do_cio(SubChannelId schid, uint16_t cutype, uint32_t ccw_addr, int fmt)
{
Irb irb = {};
SenseDataEckdDasd sd;
int rc, retries = 0;
while (true) {
rc = __do_cio(schid, ccw_addr, fmt, &irb);
if (rc == -1) {
retries++;
continue;
}
if (rc) {
/* ssch/tsch error. Message already reported by __do_cio */
break;
}
if (!irb_error(&irb)) {
break;
}
/*
* Unexpected unit check, or interface-control-check. Use sense to
* clear (unit check only) then retry.
*/
if ((unit_check(&irb) || iface_ctrl_check(&irb)) && retries <= 2) {
if (unit_check(&irb)) {
basic_sense(schid, cutype, &sd, sizeof(sd));
}
retries++;
continue;
}
rc = -1;
break;
}
return rc;
}
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