s390: add scm block driver

Block device driver for Storage Class Memory (SCM). This driver
provides a block device interface for each available SCM increment.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/block/Kconfig

@@ -70,3 +70,14 @@ config DASD_EER
 	  This driver provides a character device interface to the
 	  DASD extended error reporting. This is only needed if you want to
 	  use applications written for the EER facility.
+
+config SCM_BLOCK
+	def_tristate m
+	prompt "Support for Storage Class Memory"
+	depends on S390 && BLOCK && EADM_SCH && SCM_BUS
+	help
+	  Block device driver for Storage Class Memory (SCM). This driver
+	  provides a block device interface for each available SCM increment.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called scm_block.

drivers/s390/block/Makefile

@@ -17,3 +17,6 @@ obj-$(CONFIG_DASD_ECKD) += dasd_eckd_mod.o
 obj-$(CONFIG_DASD_FBA)  += dasd_fba_mod.o
 obj-$(CONFIG_BLK_DEV_XPRAM) += xpram.o
 obj-$(CONFIG_DCSSBLK) += dcssblk.o
+
+scm_block-objs := scm_drv.o scm_blk.o
+obj-$(CONFIG_SCM_BLOCK) += scm_block.o

drivers/s390/block/scm_blk.h

+#ifndef SCM_BLK_H
+#define SCM_BLK_H
+
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/blkdev.h>
+#include <linux/genhd.h>
+#include <linux/list.h>
+
+#include <asm/debug.h>
+#include <asm/eadm.h>
+
+#define SCM_NR_PARTS 8
+#define SCM_QUEUE_DELAY 5
+
+struct scm_blk_dev {
+	struct tasklet_struct tasklet;
+	struct request_queue *rq;
+	struct gendisk *gendisk;
+	struct scm_device *scmdev;
+	spinlock_t rq_lock;	/* guard the request queue */
+	spinlock_t lock;	/* guard the rest of the blockdev */
+	atomic_t queued_reqs;
+	struct list_head finished_requests;
+};
+
+struct scm_request {
+	struct scm_blk_dev *bdev;
+	struct request *request;
+	struct aidaw *aidaw;
+	struct aob *aob;
+	struct list_head list;
+	u8 retries;
+	int error;
+};
+
+#define to_aobrq(rq) container_of((void *) rq, struct aob_rq_header, data)
+
+int scm_blk_dev_setup(struct scm_blk_dev *, struct scm_device *);
+void scm_blk_dev_cleanup(struct scm_blk_dev *);
+void scm_blk_irq(struct scm_device *, void *, int);
+
+int scm_drv_init(void);
+void scm_drv_cleanup(void);
+
+
+extern debug_info_t *scm_debug;
+
+#define SCM_LOG(imp, txt) do {					\
+		debug_text_event(scm_debug, imp, txt);		\
+	} while (0)
+
+static inline void SCM_LOG_HEX(int level, void *data, int length)
+{
+	if (level > scm_debug->level)
+		return;
+	while (length > 0) {
+		debug_event(scm_debug, level, data, length);
+		length -= scm_debug->buf_size;
+		data += scm_debug->buf_size;
+	}
+}
+
+static inline void SCM_LOG_STATE(int level, struct scm_device *scmdev)
+{
+	struct {
+		u64 address;
+		u8 oper_state;
+		u8 rank;
+	} __packed data = {
+		.address = scmdev->address,
+		.oper_state = scmdev->attrs.oper_state,
+		.rank = scmdev->attrs.rank,
+	};
+
+	SCM_LOG_HEX(level, &data, sizeof(data));
+}
+
+#endif /* SCM_BLK_H */

drivers/s390/block/scm_drv.c

+/*
+ * Device driver for s390 storage class memory.
+ *
+ * Copyright IBM Corp. 2012
+ * Author(s): Sebastian Ott <sebott@linux.vnet.ibm.com>
+ */
+
+#define KMSG_COMPONENT "scm_block"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <asm/eadm.h>
+#include "scm_blk.h"
+
+static void notify(struct scm_device *scmdev)
+{
+	pr_info("%lu: The capabilities of the SCM increment changed\n",
+		(unsigned long) scmdev->address);
+	SCM_LOG(2, "State changed");
+	SCM_LOG_STATE(2, scmdev);
+}
+
+static int scm_probe(struct scm_device *scmdev)
+{
+	struct scm_blk_dev *bdev;
+	int ret;
+
+	SCM_LOG(2, "probe");
+	SCM_LOG_STATE(2, scmdev);
+
+	if (scmdev->attrs.oper_state != OP_STATE_GOOD)
+		return -EINVAL;
+
+	bdev = kzalloc(sizeof(*bdev), GFP_KERNEL);
+	if (!bdev)
+		return -ENOMEM;
+
+	spin_lock_irq(&scmdev->lock);
+	dev_set_drvdata(&scmdev->dev, bdev);
+	spin_unlock_irq(&scmdev->lock);
+
+	ret = scm_blk_dev_setup(bdev, scmdev);
+	if (ret) {
+		spin_lock_irq(&scmdev->lock);
+		dev_set_drvdata(&scmdev->dev, NULL);
+		spin_unlock_irq(&scmdev->lock);
+		kfree(bdev);
+		goto out;
+	}
+
+out:
+	return ret;
+}
+
+static int scm_remove(struct scm_device *scmdev)
+{
+	struct scm_blk_dev *bdev;
+
+	spin_lock_irq(&scmdev->lock);
+	bdev = dev_get_drvdata(&scmdev->dev);
+	dev_set_drvdata(&scmdev->dev, NULL);
+	spin_unlock_irq(&scmdev->lock);
+	scm_blk_dev_cleanup(bdev);
+	kfree(bdev);
+
+	return 0;
+}
+
+static struct scm_driver scm_drv = {
+	.drv = {
+		.name = "scm_block",
+		.owner = THIS_MODULE,
+	},
+	.notify = notify,
+	.probe = scm_probe,
+	.remove = scm_remove,
+	.handler = scm_blk_irq,
+};
+
+int __init scm_drv_init(void)
+{
+	return scm_driver_register(&scm_drv);
+}
+
+void scm_drv_cleanup(void)
+{
+	scm_driver_unregister(&scm_drv);
+}