[S390] get CPC image name

Provide sysfs attributes that contain the CPC name and the HMC network
name of the machine the operating system is running on. This information
is retrieved with the operation communication parameters (OCF) sclp
interface.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/Makefile

@@ -3,7 +3,7 @@
 #
 
 obj-y += ctrlchar.o keyboard.o defkeymap.o sclp.o sclp_rw.o sclp_quiesce.o \
-	 sclp_cmd.o sclp_config.o sclp_cpi_sys.o
+	 sclp_cmd.o sclp_config.o sclp_cpi_sys.o sclp_ocf.o
 
 obj-$(CONFIG_TN3270) += raw3270.o
 obj-$(CONFIG_TN3270_CONSOLE) += con3270.o

drivers/s390/char/sclp.h

@@ -28,6 +28,7 @@
 #define EVTYP_CONFMGMDATA	0x04
 #define EVTYP_SDIAS		0x1C
 #define EVTYP_ASYNC		0x0A
+#define EVTYP_OCF		0x1E
 
 #define EVTYP_OPCMD_MASK	0x80000000
 #define EVTYP_MSG_MASK		0x40000000
@@ -40,6 +41,7 @@
 #define EVTYP_CONFMGMDATA_MASK	0x10000000
 #define EVTYP_SDIAS_MASK	0x00000010
 #define EVTYP_ASYNC_MASK	0x00400000
+#define EVTYP_OCF_MASK		0x00000004
 
 #define GNRLMSGFLGS_DOM		0x8000
 #define GNRLMSGFLGS_SNDALRM	0x4000

drivers/s390/char/sclp_ocf.c

+/*
+ *  drivers/s390/char/sclp_ocf.c
+ *    SCLP OCF communication parameters sysfs interface
+ *
+ *    Copyright IBM Corp. 2011
+ *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#define KMSG_COMPONENT "sclp_ocf"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/stat.h>
+#include <linux/device.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/kmod.h>
+#include <linux/timer.h>
+#include <linux/err.h>
+#include <asm/ebcdic.h>
+#include <asm/sclp.h>
+
+#include "sclp.h"
+
+#define OCF_LENGTH_HMC_NETWORK 8UL
+#define OCF_LENGTH_CPC_NAME 8UL
+
+static char hmc_network[OCF_LENGTH_HMC_NETWORK + 1];
+static char cpc_name[OCF_LENGTH_CPC_NAME + 1];
+
+static DEFINE_SPINLOCK(sclp_ocf_lock);
+static struct work_struct sclp_ocf_change_work;
+
+static struct kset *ocf_kset;
+
+static void sclp_ocf_change_notify(struct work_struct *work)
+{
+	kobject_uevent(&ocf_kset->kobj, KOBJ_CHANGE);
+}
+
+/* Handler for OCF event. Look for the CPC image name. */
+static void sclp_ocf_handler(struct evbuf_header *evbuf)
+{
+	struct gds_vector *v;
+	struct gds_subvector *sv, *netid, *cpc;
+	size_t size;
+
+	/* Find the 0x9f00 block. */
+	v = sclp_find_gds_vector(evbuf + 1, (void *) evbuf + evbuf->length,
+				 0x9f00);
+	if (!v)
+		return;
+	/* Find the 0x9f22 block inside the 0x9f00 block. */
+	v = sclp_find_gds_vector(v + 1, (void *) v + v->length, 0x9f22);
+	if (!v)
+		return;
+	/* Find the 0x81 block inside the 0x9f22 block. */
+	sv = sclp_find_gds_subvector(v + 1, (void *) v + v->length, 0x81);
+	if (!sv)
+		return;
+	/* Find the 0x01 block inside the 0x81 block. */
+	netid = sclp_find_gds_subvector(sv + 1, (void *) sv + sv->length, 1);
+	/* Find the 0x02 block inside the 0x81 block. */
+	cpc = sclp_find_gds_subvector(sv + 1, (void *) sv + sv->length, 2);
+	/* Copy network name and cpc name. */
+	spin_lock(&sclp_ocf_lock);
+	if (netid) {
+		size = min(OCF_LENGTH_HMC_NETWORK, (size_t) netid->length);
+		memcpy(hmc_network, netid + 1, size);
+		EBCASC(hmc_network, size);
+		hmc_network[size] = 0;
+	}
+	if (cpc) {
+		size = min(OCF_LENGTH_CPC_NAME, (size_t) cpc->length);
+		memcpy(cpc_name, cpc + 1, size);
+		EBCASC(cpc_name, size);
+		cpc_name[size] = 0;
+	}
+	spin_unlock(&sclp_ocf_lock);
+	schedule_work(&sclp_ocf_change_work);
+}
+
+static struct sclp_register sclp_ocf_event = {
+	.receive_mask = EVTYP_OCF_MASK,
+	.receiver_fn = sclp_ocf_handler,
+};
+
+static ssize_t cpc_name_show(struct kobject *kobj,
+			     struct kobj_attribute *attr, char *page)
+{
+	int rc;
+
+	spin_lock_irq(&sclp_ocf_lock);
+	rc = snprintf(page, PAGE_SIZE, "%s\n", cpc_name);
+	spin_unlock_irq(&sclp_ocf_lock);
+	return rc;
+}
+
+static struct kobj_attribute cpc_name_attr =
+	__ATTR(cpc_name, 0444, cpc_name_show, NULL);
+
+static ssize_t hmc_network_show(struct kobject *kobj,
+				struct kobj_attribute *attr, char *page)
+{
+	int rc;
+
+	spin_lock_irq(&sclp_ocf_lock);
+	rc = snprintf(page, PAGE_SIZE, "%s\n", hmc_network);
+	spin_unlock_irq(&sclp_ocf_lock);
+	return rc;
+}
+
+static struct kobj_attribute hmc_network_attr =
+	__ATTR(hmc_network, 0444, hmc_network_show, NULL);
+
+static struct attribute *ocf_attrs[] = {
+	&cpc_name_attr.attr,
+	&hmc_network_attr.attr,
+	NULL,
+};
+
+static struct attribute_group ocf_attr_group = {
+	.attrs = ocf_attrs,
+};
+
+static int __init ocf_init(void)
+{
+	int rc;
+
+	INIT_WORK(&sclp_ocf_change_work, sclp_ocf_change_notify);
+	ocf_kset = kset_create_and_add("ocf", NULL, firmware_kobj);
+	if (!ocf_kset)
+		return -ENOMEM;
+
+	rc = sysfs_create_group(&ocf_kset->kobj, &ocf_attr_group);
+	if (rc) {
+		kset_unregister(ocf_kset);
+		return rc;
+	}
+
+	return sclp_register(&sclp_ocf_event);
+}
+
+device_initcall(ocf_init);