[PATCH] s390: 64 bit diag250 support

Add support for diag 250 access to dasd devices for 64 bit kernels.  In
addition fix detach/attach for diag disks.  The VM control block needs to get
recreated by a call to mdsk_init_io.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 212 insertions, 122 deletions

diff --git a/drivers/s390/block/dasd_diag.c b/drivers/s390/block/dasd_diag.c
index 127699830fa1..7478423b53bb 100644
--- a/drivers/s390/block/dasd_diag.c
+++ b/drivers/s390/block/dasd_diag.c
@@ -6,17 +6,18 @@
  * Bugreports.to..: <Linux390@de.ibm.com>
  * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999,2000
  *
- * $Revision: 1.42 $
+ * $Revision: 1.49 $
  */
 
 #include <linux/config.h>
 #include <linux/stddef.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
-#include <linux/hdreg.h>        /* HDIO_GETGEO                      */
+#include <linux/hdreg.h>
 #include <linux/bio.h>
 #include <linux/module.h>
 #include <linux/init.h>
+#include <linux/jiffies.h>
 
 #include <asm/dasd.h>
 #include <asm/debug.h>
@@ -28,58 +29,89 @@
 #include "dasd_int.h"
 #include "dasd_diag.h"
 
-#ifdef PRINTK_HEADER
-#undef PRINTK_HEADER
-#endif                          /* PRINTK_HEADER */
 #define PRINTK_HEADER "dasd(diag):"
 
 MODULE_LICENSE("GPL");
 
+/* The maximum number of blocks per request (max_blocks) is dependent on the
+ * amount of storage that is available in the static I/O buffer for each
+ * device. Currently each device gets 2 pages. We want to fit two requests
+ * into the available memory so that we can immediately start the next if one
+ * finishes. */
+#define DIAG_MAX_BLOCKS (((2 * PAGE_SIZE - sizeof(struct dasd_ccw_req) - \
+                           sizeof(struct dasd_diag_req)) / \
+                           sizeof(struct dasd_diag_bio)) / 2)
+#define DIAG_MAX_RETRIES        32
+#define DIAG_TIMEOUT            50 * HZ
+
 struct dasd_discipline dasd_diag_discipline;
 
 struct dasd_diag_private {
         struct dasd_diag_characteristics rdc_data;
         struct dasd_diag_rw_io iob;
         struct dasd_diag_init_io iib;
-        unsigned int pt_block;
+        blocknum_t pt_block;
 };
 
 struct dasd_diag_req {
-        int block_count;
+        unsigned int block_count;
         struct dasd_diag_bio bio[0];
 };
 
+static const u8 DASD_DIAG_CMS1[] = { 0xc3, 0xd4, 0xe2, 0xf1 };/* EBCDIC CMS1 */
+
+/* Perform DIAG250 call with block I/O parameter list iob (input and output)
+ * and function code cmd.
+ * In case of an exception return 3. Otherwise return result of bitwise OR of
+ * resulting condition code and DIAG return code. */
 static __inline__ int
 dia250(void *iob, int cmd)
 {
+        typedef struct {
+                char _[max(sizeof (struct dasd_diag_init_io),
+                           sizeof (struct dasd_diag_rw_io))];
+        } addr_type;
         int rc;
 
-        __asm__ __volatile__("    lhi   %0,3\n"
-                             "    lr    0,%2\n"
-                             "    diag  0,%1,0x250\n"
-                             "0:  ipm   %0\n"
-                             "    srl   %0,28\n"
-                             "    or    %0,1\n"
-                             "1:\n"
-#ifndef CONFIG_ARCH_S390X
-                             ".section __ex_table,\"a\"\n"
-                             "    .align 4\n"
-                             "    .long 0b,1b\n"
-                             ".previous\n"
+        __asm__ __volatile__(
+#ifdef CONFIG_ARCH_S390X
+                "       lghi    %0,3\n"
+                "       lgr     0,%3\n"
+                "       diag    0,%2,0x250\n"
+                "0:     ipm     %0\n"
+                "       srl     %0,28\n"
+                "       or      %0,1\n"
+                "1:\n"
+                ".section __ex_table,\"a\"\n"
+                "       .align 8\n"
+                "       .quad  0b,1b\n"
+                ".previous\n"
 #else
-                             ".section __ex_table,\"a\"\n"
-                             "    .align 8\n"
-                             "    .quad  0b,1b\n"
-                             ".previous\n"
+                "       lhi     %0,3\n"
+                "       lr      0,%3\n"
+                "       diag    0,%2,0x250\n"
+                "0:     ipm     %0\n"
+                "       srl     %0,28\n"
+                "       or      %0,1\n"
+                "1:\n"
+                ".section __ex_table,\"a\"\n"
+                "       .align 4\n"
+                "       .long 0b,1b\n"
+                ".previous\n"
 #endif
-                             : "=&d" (rc)
-                             : "d" (cmd), "d" ((void *) __pa(iob))
-                             : "0", "1", "cc");
+                : "=&d" (rc), "=m" (*(addr_type *) iob)
+                : "d" (cmd), "d" (iob), "m" (*(addr_type *) iob)
+                : "0", "1", "cc");
         return rc;
 }
 
+/* Initialize block I/O to DIAG device using the specified blocksize and
+ * block offset. On success, return zero and set end_block to contain the
+ * number of blocks on the device minus the specified offset. Return non-zero
+ * otherwise. */
 static __inline__ int
-mdsk_init_io(struct dasd_device * device, int blocksize, int offset, int size)
+mdsk_init_io(struct dasd_device *device, unsigned int blocksize,
+             blocknum_t offset, blocknum_t *end_block)
 {
         struct dasd_diag_private *private;
         struct dasd_diag_init_io *iib;
@@ -92,14 +124,18 @@ mdsk_init_io(struct dasd_device * device, int blocksize, int offset, int size)
         iib->dev_nr = _ccw_device_get_device_number(device->cdev);
         iib->block_size = blocksize;
         iib->offset = offset;
-        iib->start_block = 0;
-        iib->end_block = size;
+        iib->flaga = DASD_DIAG_FLAGA_DEFAULT;
 
         rc = dia250(iib, INIT_BIO);
 
-        return rc & 3;
+        if ((rc & 3) == 0 && end_block)
+                *end_block = iib->end_block;
+
+        return rc;
 }
 
+/* Remove block I/O environment for device. Return zero on success, non-zero
+ * otherwise. */
 static __inline__ int
 mdsk_term_io(struct dasd_device * device)
 {
@@ -112,9 +148,25 @@ mdsk_term_io(struct dasd_device * device)
         memset(iib, 0, sizeof (struct dasd_diag_init_io));
         iib->dev_nr = _ccw_device_get_device_number(device->cdev);
         rc = dia250(iib, TERM_BIO);
-        return rc & 3;
+        return rc;
+}
+
+/* Error recovery for failed DIAG requests - try to reestablish the DIAG
+ * environment. */
+static void
+dasd_diag_erp(struct dasd_device *device)
+{
+        int rc;
+
+        mdsk_term_io(device);
+        rc = mdsk_init_io(device, device->bp_block, 0, NULL);
+        if (rc)
+                DEV_MESSAGE(KERN_WARNING, device, "DIAG ERP unsuccessful, "
+                            "rc=%d", rc);
 }
 
+/* Start a given request at the device. Return zero on success, non-zero
+ * otherwise. */
 static int
 dasd_start_diag(struct dasd_ccw_req * cqr)
 {
@@ -124,32 +176,66 @@ dasd_start_diag(struct dasd_ccw_req * cqr)
         int rc;
 
         device = cqr->device;
+        if (cqr->retries < 0) {
+                DEV_MESSAGE(KERN_WARNING, device, "DIAG start_IO: request %p "
+                            "- no retry left)", cqr);
+                cqr->status = DASD_CQR_FAILED;
+                return -EIO;
+        }
         private = (struct dasd_diag_private *) device->private;
         dreq = (struct dasd_diag_req *) cqr->data;
 
         private->iob.dev_nr = _ccw_device_get_device_number(device->cdev);
         private->iob.key = 0;
-        private->iob.flags = 2; /* do asynchronous io */
+        private->iob.flags = DASD_DIAG_RWFLAG_ASYNC;
         private->iob.block_count = dreq->block_count;
-        private->iob.interrupt_params = (u32)(addr_t) cqr;
+        private->iob.interrupt_params = (addr_t) cqr;
         private->iob.bio_list = __pa(dreq->bio);
+        private->iob.flaga = DASD_DIAG_FLAGA_DEFAULT;
 
         cqr->startclk = get_clock();
+        cqr->starttime = jiffies;
+        cqr->retries--;
 
         rc = dia250(&private->iob, RW_BIO);
-        if (rc > 8) {
-                DEV_MESSAGE(KERN_WARNING, device, "dia250 returned CC %d", rc);
-                cqr->status = DASD_CQR_ERROR;
-        } else if (rc == 0) {
+        switch (rc) {
+        case 0: /* Synchronous I/O finished successfully */
+                cqr->stopclk = get_clock();
                 cqr->status = DASD_CQR_DONE;
-                dasd_schedule_bh(device);
-        } else {
+                /* Indicate to calling function that only a dasd_schedule_bh()
+                   and no timer is needed */
+                rc = -EACCES;
+                break;
+        case 8: /* Asynchronous I/O was started */
                 cqr->status = DASD_CQR_IN_IO;
                 rc = 0;
+                break;
+        default: /* Error condition */
+                cqr->status = DASD_CQR_QUEUED;
+                DEV_MESSAGE(KERN_WARNING, device, "dia250 returned rc=%d", rc);
+                dasd_diag_erp(device);
+                rc = -EIO;
+                break;
         }
         return rc;
 }
 
+/* Terminate given request at the device. */
+static int
+dasd_diag_term_IO(struct dasd_ccw_req * cqr)
+{
+        struct dasd_device *device;
+
+        device = cqr->device;
+        mdsk_term_io(device);
+        mdsk_init_io(device, device->bp_block, 0, NULL);
+        cqr->status = DASD_CQR_CLEAR;
+        cqr->stopclk = get_clock();
+        dasd_schedule_bh(device);
+        return 0;
+}
+
+/* Handle external interruption. */
 static void
 dasd_ext_handler(struct pt_regs *regs, __u16 code)
 {
@@ -157,25 +243,27 @@ dasd_ext_handler(struct pt_regs *regs, __u16 code)
         struct dasd_device *device;
         unsigned long long expires;
         unsigned long flags;
-        char status;
-        int ip;
-
-        /*
-         * Get the external interruption subcode. VM stores
-         * this in the 'cpu address' field associated with
-         * the external interrupt. For diag 250 the subcode
-         * needs to be 3.
-         */
-        if ((S390_lowcore.cpu_addr & 0xff00) != 0x0300)
-                return;
-        status = *((char *) &S390_lowcore.ext_params + 5);
-        ip = S390_lowcore.ext_params;
+        u8 int_code, status;
+        addr_t ip;
+        int rc;
 
+        int_code = *((u8 *) DASD_DIAG_LC_INT_CODE);
+        status = *((u8 *) DASD_DIAG_LC_INT_STATUS);
+        switch (int_code) {
+        case DASD_DIAG_CODE_31BIT:
+                ip = (addr_t) *((u32 *) DASD_DIAG_LC_INT_PARM_31BIT);
+                break;
+        case DASD_DIAG_CODE_64BIT:
+                ip = (addr_t) *((u64 *) DASD_DIAG_LC_INT_PARM_64BIT);
+                break;
+        default:
+                return;
+        }
         if (!ip) {              /* no intparm: unsolicited interrupt */
                 MESSAGE(KERN_DEBUG, "%s", "caught unsolicited interrupt");
                 return;
         }
-        cqr = (struct dasd_ccw_req *)(addr_t) ip;
+        cqr = (struct dasd_ccw_req *) ip;
         device = (struct dasd_device *) cqr->device;
         if (strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
                 DEV_MESSAGE(KERN_WARNING, device,
@@ -188,6 +276,15 @@ dasd_ext_handler(struct pt_regs *regs, __u16 code)
         /* get irq lock to modify request queue */
         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 
+        /* Check for a pending clear operation */
+        if (cqr->status == DASD_CQR_CLEAR) {
+                cqr->status = DASD_CQR_QUEUED;
+                dasd_clear_timer(device);
+                dasd_schedule_bh(device);
+                spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+                return;
+        }
+
         cqr->stopclk = get_clock();
 
         expires = 0;
@@ -198,16 +295,22 @@ dasd_ext_handler(struct pt_regs *regs, __u16 code)
                         next = list_entry(device->ccw_queue.next,
                                           struct dasd_ccw_req, list);
                         if (next->status == DASD_CQR_QUEUED) {
-                                if (dasd_start_diag(next) == 0)
+                                rc = dasd_start_diag(next);
+                                if (rc == 0)
                                         expires = next->expires;
-                                else
+                                else if (rc != -EACCES)
                                         DEV_MESSAGE(KERN_WARNING, device, "%s",
                                                     "Interrupt fastpath "
                                                     "failed!");
                         }
                 }
-        } else 
-                cqr->status = DASD_CQR_FAILED;
+        } else {
+                cqr->status = DASD_CQR_QUEUED;
+                DEV_MESSAGE(KERN_WARNING, device, "interrupt status for "
+                            "request %p was %d (%d retries left)", cqr, status,
+                            cqr->retries);
+                dasd_diag_erp(device);
+        }
 
         if (expires != 0)
                 dasd_set_timer(device, expires);
@@ -218,14 +321,17 @@ dasd_ext_handler(struct pt_regs *regs, __u16 code)
         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 }
 
+/* Check whether device can be controlled by DIAG discipline. Return zero on
+ * success, non-zero otherwise. */
 static int
 dasd_diag_check_device(struct dasd_device *device)
 {
         struct dasd_diag_private *private;
         struct dasd_diag_characteristics *rdc_data;
         struct dasd_diag_bio bio;
-        long *label;
-        int sb, bsize;
+        struct dasd_diag_cms_label *label;
+        blocknum_t end_block;
+        unsigned int sb, bsize;
         int rc;
 
         private = (struct dasd_diag_private *) device->private;
@@ -244,8 +350,11 @@ dasd_diag_check_device(struct dasd_device *device)
         rdc_data->rdc_len = sizeof (struct dasd_diag_characteristics);
 
         rc = diag210((struct diag210 *) rdc_data);
-        if (rc)
+        if (rc) {
+                DEV_MESSAGE(KERN_WARNING, device, "failed to retrieve device "
+                            "information (rc=%d)", rc);
                 return -ENOTSUPP;
+        }
 
         /* Figure out position of label block */
         switch (private->rdc_data.vdev_class) {
@@ -256,6 +365,8 @@ dasd_diag_check_device(struct dasd_device *device)
                 private->pt_block = 2;
                 break;
         default:
+                DEV_MESSAGE(KERN_WARNING, device, "unsupported device class "
+                            "(class=%d)", private->rdc_data.vdev_class);
                 return -ENOTSUPP;
         }
 
@@ -269,15 +380,17 @@ dasd_diag_check_device(struct dasd_device *device)
         mdsk_term_io(device);
 
         /* figure out blocksize of device */
-        label = (long *) get_zeroed_page(GFP_KERNEL);
+        label = (struct dasd_diag_cms_label *) get_zeroed_page(GFP_KERNEL);
         if (label == NULL)  {
                 DEV_MESSAGE(KERN_WARNING, device, "%s",
                             "No memory to allocate initialization request");
                 return -ENOMEM;
         }
+        rc = 0;
+        end_block = 0;
         /* try all sizes - needed for ECKD devices */
         for (bsize = 512; bsize <= PAGE_SIZE; bsize <<= 1) {
-                mdsk_init_io(device, bsize, 0, 64);
+                mdsk_init_io(device, bsize, 0, &end_block);
                 memset(&bio, 0, sizeof (struct dasd_diag_bio));
                 bio.type = MDSK_READ_REQ;
                 bio.block_number = private->pt_block + 1;
@@ -289,37 +402,45 @@ dasd_diag_check_device(struct dasd_device *device)
                 private->iob.block_count = 1;
                 private->iob.interrupt_params = 0;
                 private->iob.bio_list = __pa(&bio);
-                if (dia250(&private->iob, RW_BIO) == 0)
+                private->iob.flaga = DASD_DIAG_FLAGA_DEFAULT;
+                rc = dia250(&private->iob, RW_BIO);
+                if (rc == 0 || rc == 3)
                         break;
                 mdsk_term_io(device);
         }
-        if (bsize <= PAGE_SIZE && label[0] == 0xc3d4e2f1) {
-                /* get formatted blocksize from label block */
-                bsize = (int) label[3];
-                device->blocks = label[7];
+        if (rc == 3) {
+                DEV_MESSAGE(KERN_WARNING, device, "%s", "DIAG call failed");
+                rc = -EOPNOTSUPP;
+        } else if (rc != 0) {
+                DEV_MESSAGE(KERN_WARNING, device, "device access failed "
+                            "(rc=%d)", rc);
+                rc = -EIO;
+        } else {
+                if (memcmp(label->label_id, DASD_DIAG_CMS1,
+                          sizeof(DASD_DIAG_CMS1)) == 0) {
+                        /* get formatted blocksize from label block */
+                        bsize = (unsigned int) label->block_size;
+                        device->blocks = (unsigned long) label->block_count;
+                } else
+                        device->blocks = end_block;
                 device->bp_block = bsize;
                 device->s2b_shift = 0;  /* bits to shift 512 to get a block */
                 for (sb = 512; sb < bsize; sb = sb << 1)
                         device->s2b_shift++;
                 
                 DEV_MESSAGE(KERN_INFO, device,
-                            "capacity (%dkB blks): %ldkB",
-                            (device->bp_block >> 10),
-                            (device->blocks << device->s2b_shift) >> 1);
+                            "(%ld B/blk): %ldkB",
+                            (unsigned long) device->bp_block,
+                            (unsigned long) (device->blocks <<
+                                device->s2b_shift) >> 1);
                 rc = 0;
-        } else {
-                if (bsize > PAGE_SIZE)
-                        DEV_MESSAGE(KERN_WARNING, device, "%s",
-                                    "DIAG access failed");
-                else
-                        DEV_MESSAGE(KERN_WARNING, device, "%s",
-                                    "volume is not CMS formatted");
-                rc = -EMEDIUMTYPE;
         }
         free_page((long) label);
         return rc;
 }
 
+/* Fill in virtual disk geometry for device. Return zero on success, non-zero
+ * otherwise. */
 static int
 dasd_diag_fill_geometry(struct dasd_device *device, struct hd_geometry *geo)
 {
@@ -349,6 +470,8 @@ dasd_diag_erp_postaction(struct dasd_ccw_req * cqr)
         return dasd_default_erp_postaction;
 }
 
+/* Create DASD request from block device request. Return pointer to new
+ * request on success, ERR_PTR otherwise. */
 static struct dasd_ccw_req *
 dasd_diag_build_cp(struct dasd_device * device, struct request *req)
 {
@@ -358,9 +481,9 @@ dasd_diag_build_cp(struct dasd_device * device, struct request *req)
         struct bio *bio;
         struct bio_vec *bv;
         char *dst;
-        int count, datasize;
+        unsigned int count, datasize;
         sector_t recid, first_rec, last_rec;
-        unsigned blksize, off;
+        unsigned int blksize, off;
         unsigned char rw_cmd;
         int i;
 
@@ -413,13 +536,16 @@ dasd_diag_build_cp(struct dasd_device * device, struct request *req)
                         }
                 }
         }
+        cqr->retries = DIAG_MAX_RETRIES;
         cqr->buildclk = get_clock();
         cqr->device = device;
-        cqr->expires = 50 * HZ; /* 50 seconds */
+        cqr->expires = DIAG_TIMEOUT;
         cqr->status = DASD_CQR_FILLED;
         return cqr;
 }
 
+/* Release DASD request. Return non-zero if request was successful, zero
+ * otherwise. */
 static int
 dasd_diag_free_cp(struct dasd_ccw_req *cqr, struct request *req)
 {
@@ -430,6 +556,7 @@ dasd_diag_free_cp(struct dasd_ccw_req *cqr, struct request *req)
         return status;
 }
 
+/* Fill in IOCTL data for device. */
 static int
 dasd_diag_fill_info(struct dasd_device * device,
                     struct dasd_information2_t * info)
@@ -437,7 +564,7 @@ dasd_diag_fill_info(struct dasd_device * device,
         struct dasd_diag_private *private;
 
         private = (struct dasd_diag_private *) device->private;
-        info->label_block = private->pt_block;
+        info->label_block = (unsigned int) private->pt_block;
         info->FBA_layout = 1;
         info->format = DASD_FORMAT_LDL;
         info->characteristics_size = sizeof (struct dasd_diag_characteristics);
@@ -456,26 +583,15 @@ dasd_diag_dump_sense(struct dasd_device *device, struct dasd_ccw_req * req,
                     "dump sense not available for DIAG data");
 }
 
-/*
- * max_blocks is dependent on the amount of storage that is available
- * in the static io buffer for each device. Currently each device has
- * 8192 bytes (=2 pages). dasd diag is only relevant for 31 bit.
- * The struct dasd_ccw_req has 96 bytes, the struct dasd_diag_req has
- * 8 bytes and the struct dasd_diag_bio for each block has 16 bytes. 
- * That makes:
- * (8192 - 96 - 8) / 16 = 505.5 blocks at maximum.
- * We want to fit two into the available memory so that we can immediately
- * start the next request if one finishes off. That makes 252.75 blocks
- * for one request. Give a little safety and the result is 240.
- */
 struct dasd_discipline dasd_diag_discipline = {
         .owner = THIS_MODULE,
         .name = "DIAG",
         .ebcname = "DIAG",
-        .max_blocks = 240,
+        .max_blocks = DIAG_MAX_BLOCKS,
         .check_device = dasd_diag_check_device,
         .fill_geometry = dasd_diag_fill_geometry,
         .start_IO = dasd_start_diag,
+        .term_IO = dasd_diag_term_IO,
         .examine_error = dasd_diag_examine_error,
         .erp_action = dasd_diag_erp_action,
         .erp_postaction = dasd_diag_erp_postaction,
@@ -493,7 +609,7 @@ dasd_diag_init(void)
                             "Machine is not VM: %s "
                             "discipline not initializing",
                             dasd_diag_discipline.name);
-                return -EINVAL;
+                return -ENODEV;
         }
         ASCEBC(dasd_diag_discipline.ebcname, 4);
 
@@ -506,13 +622,6 @@ dasd_diag_init(void)
 static void __exit
 dasd_diag_cleanup(void)
 {
-        if (!MACHINE_IS_VM) {
-                MESSAGE_LOG(KERN_INFO,
-                            "Machine is not VM: %s "
-                            "discipline not cleaned",
-                            dasd_diag_discipline.name);
-                return;
-        }
         unregister_external_interrupt(0x2603, dasd_ext_handler);
         ctl_clear_bit(0, 9);
         dasd_diag_discipline_pointer = NULL;
@@ -520,22 +629,3 @@ dasd_diag_cleanup(void)
 
 module_init(dasd_diag_init);
 module_exit(dasd_diag_cleanup);
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-indent-level: 4 
- * c-brace-imaginary-offset: 0
- * c-brace-offset: -4
- * c-argdecl-indent: 4
- * c-label-offset: -4
- * c-continued-statement-offset: 4
- * c-continued-brace-offset: 0
- * indent-tabs-mode: 1
- * tab-width: 8
- * End:
- */