s390-bios: Support for running format-0/1 channel programs

Introduce a library function for executing format-0 and format-1
channel programs and waiting for their completion before continuing
execution.

Add cu_type() to channel io library. This will be used to query control
unit type which is used to determine if we are booting a virtio device or a
real dasd device.

Signed-off-by: Jason J. Herne <jjherne@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Farhan Ali <alifm@linux.ibm.com>
Message-Id: <1554388475-18329-9-git-send-email-jjherne@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

1 files changed, 144 insertions, 0 deletions

diff --git a/pc-bios/s390-ccw/cio.c b/pc-bios/s390-ccw/cio.c
index 87c6b34e88..c43e50b00b 100644
--- a/pc-bios/s390-ccw/cio.c
+++ b/pc-bios/s390-ccw/cio.c
@@ -13,10 +13,14 @@
 
 #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;
@@ -42,3 +46,143 @@ void enable_subchannel(SubChannelId schid)
     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;
+}