[S390] zcrypt adjunct processor bus.

Add a bus for the adjunct processor interface. Up to 64 devices can
be connect to the ap bus interface, each device with 16 domains. That
makes 1024 message queues. The interface is asynchronous, the answer
to a message sent to a queue needs to be received at some later point
in time. Unfortunately the interface does not provide interrupts when
a message reply is pending. So the ap bus needs to implement some
fancy polling, each active queue is polled once per 1/HZ second or
continuously if an idle cpus exsists and the poll thread is activ
(see poll_thread parameter).

The ap bus uses the sysfs path /sys/bus/ap and has two bus attributes,
ap_domain and config_time. The ap_domain selects one of the 16 domains
to be used for this system. This limits the maximum number of ap devices
to 64. The config_time attribute contains the number of seconds between
two ap bus scans to find new devices.

The ap bus uses the modalias entries of the form "ap:tN" to autoload
the ap driver for hardware type N. Currently known types are:
3 - PCICC, 4 - PCICA, 5 - PCIXCC, 6 - CEX2A and 7 - CEX2C.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Ralph Wuerthner <rwuerthn@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 158 insertions, 0 deletions

diff --git a/drivers/s390/crypto/ap_bus.h b/drivers/s390/crypto/ap_bus.h
new file mode 100644
index 000000000000..83b69c01cd6e
--- /dev/null
+++ b/drivers/s390/crypto/ap_bus.h
@@ -0,0 +1,158 @@
+/*
+ * linux/drivers/s390/crypto/ap_bus.h
+ *
+ * Copyright (C) 2006 IBM Corporation
+ * Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
+ *            Martin Schwidefsky <schwidefsky@de.ibm.com>
+ *            Ralph Wuerthner <rwuerthn@de.ibm.com>
+ *
+ * Adjunct processor bus header file.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef _AP_BUS_H_
+#define _AP_BUS_H_
+
+#include <linux/device.h>
+#include <linux/mod_devicetable.h>
+#include <linux/types.h>
+
+#define AP_DEVICES 64           /* Number of AP devices. */
+#define AP_DOMAINS 16           /* Number of AP domains. */
+#define AP_MAX_RESET 90         /* Maximum number of resets. */
+#define AP_CONFIG_TIME 30       /* Time in seconds between AP bus rescans. */
+#define AP_POLL_TIME 1          /* Time in ticks between receive polls. */
+
+extern int ap_domain_index;
+
+/**
+ * The ap_qid_t identifier of an ap queue. It contains a
+ * 6 bit device index and a 4 bit queue index (domain).
+ */
+typedef unsigned int ap_qid_t;
+
+#define AP_MKQID(_device,_queue) (((_device) & 63) << 8 | ((_queue) & 15))
+#define AP_QID_DEVICE(_qid) (((_qid) >> 8) & 63)
+#define AP_QID_QUEUE(_qid) ((_qid) & 15)
+
+/**
+ * The ap queue status word is returned by all three AP functions
+ * (PQAP, NQAP and DQAP).  There's a set of flags in the first
+ * byte, followed by a 1 byte response code.
+ */
+struct ap_queue_status {
+        unsigned int queue_empty        : 1;
+        unsigned int replies_waiting    : 1;
+        unsigned int queue_full         : 1;
+        unsigned int pad1               : 5;
+        unsigned int response_code      : 8;
+        unsigned int pad2               : 16;
+};
+
+#define AP_RESPONSE_NORMAL              0x00
+#define AP_RESPONSE_Q_NOT_AVAIL         0x01
+#define AP_RESPONSE_RESET_IN_PROGRESS   0x02
+#define AP_RESPONSE_DECONFIGURED        0x03
+#define AP_RESPONSE_CHECKSTOPPED        0x04
+#define AP_RESPONSE_BUSY                0x05
+#define AP_RESPONSE_Q_FULL              0x10
+#define AP_RESPONSE_NO_PENDING_REPLY    0x10
+#define AP_RESPONSE_INDEX_TOO_BIG       0x11
+#define AP_RESPONSE_NO_FIRST_PART       0x13
+#define AP_RESPONSE_MESSAGE_TOO_BIG     0x15
+
+/**
+ * Known device types
+ */
+#define AP_DEVICE_TYPE_PCICC    3
+#define AP_DEVICE_TYPE_PCICA    4
+#define AP_DEVICE_TYPE_PCIXCC   5
+#define AP_DEVICE_TYPE_CEX2A    6
+#define AP_DEVICE_TYPE_CEX2C    7
+
+struct ap_device;
+struct ap_message;
+
+struct ap_driver {
+        struct device_driver driver;
+        struct ap_device_id *ids;
+
+        int (*probe)(struct ap_device *);
+        void (*remove)(struct ap_device *);
+        /* receive is called from tasklet context */
+        void (*receive)(struct ap_device *, struct ap_message *,
+                        struct ap_message *);
+};
+
+#define to_ap_drv(x) container_of((x), struct ap_driver, driver)
+
+int ap_driver_register(struct ap_driver *, struct module *, char *);
+void ap_driver_unregister(struct ap_driver *);
+
+struct ap_device {
+        struct device device;
+        struct ap_driver *drv;          /* Pointer to AP device driver. */
+        spinlock_t lock;                /* Per device lock. */
+
+        ap_qid_t qid;                   /* AP queue id. */
+        int queue_depth;                /* AP queue depth.*/
+        int device_type;                /* AP device type. */
+        int unregistered;               /* marks AP device as unregistered */
+
+        int queue_count;                /* # messages currently on AP queue. */
+
+        struct list_head pendingq;      /* List of message sent to AP queue. */
+        int pendingq_count;             /* # requests on pendingq list. */
+        struct list_head requestq;      /* List of message yet to be sent. */
+        int requestq_count;             /* # requests on requestq list. */
+        int total_request_count;        /* # requests ever for this AP device. */
+
+        struct ap_message *reply;       /* Per device reply message. */
+
+        void *private;                  /* ap driver private pointer. */
+};
+
+#define to_ap_dev(x) container_of((x), struct ap_device, device)
+
+struct ap_message {
+        struct list_head list;          /* Request queueing. */
+        unsigned long long psmid;       /* Message id. */
+        void *message;                  /* Pointer to message buffer. */
+        size_t length;                  /* Message length. */
+
+        void *private;                  /* ap driver private pointer. */
+};
+
+#define AP_DEVICE(dt)                                   \
+        .dev_type=(dt),                                 \
+        .match_flags=AP_DEVICE_ID_MATCH_DEVICE_TYPE,
+
+/**
+ * Note: don't use ap_send/ap_recv after using ap_queue_message
+ * for the first time. Otherwise the ap message queue will get
+ * confused.
+ */
+int ap_send(ap_qid_t, unsigned long long, void *, size_t);
+int ap_recv(ap_qid_t, unsigned long long *, void *, size_t);
+
+void ap_queue_message(struct ap_device *ap_dev, struct ap_message *ap_msg);
+void ap_cancel_message(struct ap_device *ap_dev, struct ap_message *ap_msg);
+void ap_flush_queue(struct ap_device *ap_dev);
+
+int ap_module_init(void);
+void ap_module_exit(void);
+
+#endif /* _AP_BUS_H_ */