2 * Copyright (C) 2001-2006 Silicon Graphics, Inc. All rights
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of version 2 of the GNU General Public License
7 * as published by the Free Software Foundation.
11 * SN Platform Special Memory (mspec) Support
13 * This driver exports the SN special memory (mspec) facility to user
15 * There are three types of memory made available thru this driver:
16 * fetchops, uncached and cached.
18 * Fetchops are atomic memory operations that are implemented in the
19 * memory controller on SGI SN hardware.
21 * Uncached are used for memory write combining feature of the ia64
24 * Cached are used for areas of memory that are used as cached addresses
25 * on our partition and used as uncached addresses from other partitions.
26 * Due to a design constraint of the SN2 Shub, you can not have processors
27 * on the same FSB perform both a cached and uncached reference to the
28 * same cache line. These special memory cached regions prevent the
29 * kernel from ever dropping in a TLB entry and therefore prevent the
30 * processor from ever speculating a cache line from this page.
33 #include <linux/types.h>
34 #include <linux/kernel.h>
35 #include <linux/module.h>
36 #include <linux/init.h>
37 #include <linux/errno.h>
38 #include <linux/miscdevice.h>
39 #include <linux/spinlock.h>
41 #include <linux/vmalloc.h>
42 #include <linux/string.h>
43 #include <linux/slab.h>
44 #include <linux/numa.h>
46 #include <asm/system.h>
47 #include <asm/pgtable.h>
48 #include <asm/atomic.h>
49 #include <asm/tlbflush.h>
50 #include <asm/uncached.h>
51 #include <asm/sn/addrs.h>
52 #include <asm/sn/arch.h>
53 #include <asm/sn/mspec.h>
54 #include <asm/sn/sn_cpuid.h>
55 #include <asm/sn/io.h>
56 #include <asm/sn/bte.h>
57 #include <asm/sn/shubio.h>
60 #define FETCHOP_ID "SGI Fetchop,"
61 #define CACHED_ID "Cached,"
62 #define UNCACHED_ID "Uncached"
63 #define REVISION "4.0"
64 #define MSPEC_BASENAME "mspec"
67 * Page types allocated by the device.
78 * One of these structures is allocated when an mspec region is mmaped. The
79 * structure is pointed to by the vma->vm_private_data field in the vma struct.
80 * This structure is used to record the addresses of the mspec pages.
83 atomic_t refcnt
; /* Number of vmas sharing the data. */
84 spinlock_t lock
; /* Serialize access to the vma. */
85 int count
; /* Number of pages allocated. */
86 int type
; /* Type of pages allocated. */
87 unsigned long maddr
[0]; /* Array of MSPEC addresses. */
90 /* used on shub2 to clear FOP cache in the HUB */
91 static unsigned long scratch_page
[MAX_NUMNODES
];
92 #define SH2_AMO_CACHE_ENTRIES 4
95 mspec_zero_block(unsigned long addr
, int len
)
105 nid
= nasid_to_cnodeid(get_node_number(__pa(addr
)));
106 p
= (void *)TO_AMO(scratch_page
[nid
]);
108 for (i
=0; i
< SH2_AMO_CACHE_ENTRIES
; i
++) {
109 FETCHOP_LOAD_OP(p
, FETCHOP_LOAD
);
110 p
+= FETCHOP_VAR_SIZE
;
114 status
= bte_copy(0, addr
& ~__IA64_UNCACHED_OFFSET
, len
,
115 BTE_WACQUIRE
| BTE_ZERO_FILL
, NULL
);
117 memset((char *) addr
, 0, len
);
126 * Called when a device mapping is created by a means other than mmap
127 * (via fork, etc.). Increments the reference count on the underlying
128 * mspec data so it is not freed prematurely.
131 mspec_open(struct vm_area_struct
*vma
)
133 struct vma_data
*vdata
;
135 vdata
= vma
->vm_private_data
;
136 atomic_inc(&vdata
->refcnt
);
142 * Called when unmapping a device mapping. Frees all mspec pages
143 * belonging to the vma.
146 mspec_close(struct vm_area_struct
*vma
)
148 struct vma_data
*vdata
;
149 int i
, pages
, result
, vdata_size
;
151 vdata
= vma
->vm_private_data
;
152 if (!atomic_dec_and_test(&vdata
->refcnt
))
155 pages
= (vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
;
156 vdata_size
= sizeof(struct vma_data
) + pages
* sizeof(long);
157 for (i
= 0; i
< pages
; i
++) {
158 if (vdata
->maddr
[i
] == 0)
161 * Clear the page before sticking it back
164 result
= mspec_zero_block(vdata
->maddr
[i
], PAGE_SIZE
);
166 uncached_free_page(vdata
->maddr
[i
]);
168 printk(KERN_WARNING
"mspec_close(): "
169 "failed to zero page %i\n",
173 if (vdata_size
<= PAGE_SIZE
)
183 * Creates a mspec page and maps it to user space.
186 mspec_nopfn(struct vm_area_struct
*vma
, unsigned long address
)
188 unsigned long paddr
, maddr
;
191 struct vma_data
*vdata
= vma
->vm_private_data
;
193 index
= (address
- vma
->vm_start
) >> PAGE_SHIFT
;
194 maddr
= (volatile unsigned long) vdata
->maddr
[index
];
196 maddr
= uncached_alloc_page(numa_node_id());
200 spin_lock(&vdata
->lock
);
201 if (vdata
->maddr
[index
] == 0) {
203 vdata
->maddr
[index
] = maddr
;
205 uncached_free_page(maddr
);
206 maddr
= vdata
->maddr
[index
];
208 spin_unlock(&vdata
->lock
);
211 if (vdata
->type
== MSPEC_FETCHOP
)
212 paddr
= TO_AMO(maddr
);
214 paddr
= __pa(TO_CAC(maddr
));
216 pfn
= paddr
>> PAGE_SHIFT
;
221 static struct vm_operations_struct mspec_vm_ops
= {
223 .close
= mspec_close
,
230 * Called when mmaping the device. Initializes the vma with a fault handler
231 * and private data structure necessary to allocate, track, and free the
235 mspec_mmap(struct file
*file
, struct vm_area_struct
*vma
, int type
)
237 struct vma_data
*vdata
;
238 int pages
, vdata_size
;
240 if (vma
->vm_pgoff
!= 0)
243 if ((vma
->vm_flags
& VM_SHARED
) == 0)
246 if ((vma
->vm_flags
& VM_WRITE
) == 0)
249 pages
= (vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
;
250 vdata_size
= sizeof(struct vma_data
) + pages
* sizeof(long);
251 if (vdata_size
<= PAGE_SIZE
)
252 vdata
= kmalloc(vdata_size
, GFP_KERNEL
);
254 vdata
= vmalloc(vdata_size
);
257 memset(vdata
, 0, vdata_size
);
260 spin_lock_init(&vdata
->lock
);
261 vdata
->refcnt
= ATOMIC_INIT(1);
262 vma
->vm_private_data
= vdata
;
264 vma
->vm_flags
|= (VM_IO
| VM_LOCKED
| VM_RESERVED
| VM_PFNMAP
);
265 if (vdata
->type
== MSPEC_FETCHOP
|| vdata
->type
== MSPEC_UNCACHED
)
266 vma
->vm_page_prot
= pgprot_noncached(vma
->vm_page_prot
);
267 vma
->vm_ops
= &mspec_vm_ops
;
273 fetchop_mmap(struct file
*file
, struct vm_area_struct
*vma
)
275 return mspec_mmap(file
, vma
, MSPEC_FETCHOP
);
279 cached_mmap(struct file
*file
, struct vm_area_struct
*vma
)
281 return mspec_mmap(file
, vma
, MSPEC_CACHED
);
285 uncached_mmap(struct file
*file
, struct vm_area_struct
*vma
)
287 return mspec_mmap(file
, vma
, MSPEC_UNCACHED
);
290 static struct file_operations fetchop_fops
= {
291 .owner
= THIS_MODULE
,
295 static struct miscdevice fetchop_miscdev
= {
296 .minor
= MISC_DYNAMIC_MINOR
,
297 .name
= "sgi_fetchop",
298 .fops
= &fetchop_fops
301 static struct file_operations cached_fops
= {
302 .owner
= THIS_MODULE
,
306 static struct miscdevice cached_miscdev
= {
307 .minor
= MISC_DYNAMIC_MINOR
,
308 .name
= "mspec_cached",
312 static struct file_operations uncached_fops
= {
313 .owner
= THIS_MODULE
,
314 .mmap
= uncached_mmap
317 static struct miscdevice uncached_miscdev
= {
318 .minor
= MISC_DYNAMIC_MINOR
,
319 .name
= "mspec_uncached",
320 .fops
= &uncached_fops
326 * Called at boot time to initialize the mspec facility.
335 * The fetchop device only works on SN2 hardware, uncached and cached
336 * memory drivers should both be valid on all ia64 hardware
338 if (ia64_platform_is("sn2")) {
342 for_each_online_node(nid
) {
347 scratch_page
[nid
] = uncached_alloc_page(nid
);
348 if (scratch_page
[nid
] == 0)
349 goto free_scratch_pages
;
350 phys
= __pa(scratch_page
[nid
]);
351 nasid
= get_node_number(phys
);
352 actual_nid
= nasid_to_cnodeid(nasid
);
353 if (actual_nid
!= nid
)
354 goto free_scratch_pages
;
358 ret
= misc_register(&fetchop_miscdev
);
361 "%s: failed to register device %i\n",
363 goto free_scratch_pages
;
366 ret
= misc_register(&cached_miscdev
);
368 printk(KERN_ERR
"%s: failed to register device %i\n",
371 misc_deregister(&fetchop_miscdev
);
372 goto free_scratch_pages
;
374 ret
= misc_register(&uncached_miscdev
);
376 printk(KERN_ERR
"%s: failed to register device %i\n",
378 misc_deregister(&cached_miscdev
);
380 misc_deregister(&fetchop_miscdev
);
381 goto free_scratch_pages
;
384 printk(KERN_INFO
"%s %s initialized devices: %s %s %s\n",
385 MSPEC_BASENAME
, REVISION
, is_sn2
? FETCHOP_ID
: "",
386 CACHED_ID
, UNCACHED_ID
);
392 if (scratch_page
[nid
] != 0)
393 uncached_free_page(scratch_page
[nid
]);
403 misc_deregister(&uncached_miscdev
);
404 misc_deregister(&cached_miscdev
);
406 misc_deregister(&fetchop_miscdev
);
409 if (scratch_page
[nid
] != 0)
410 uncached_free_page(scratch_page
[nid
]);
415 module_init(mspec_init
);
416 module_exit(mspec_exit
);
418 MODULE_AUTHOR("Silicon Graphics, Inc. <linux-altix@sgi.com>");
419 MODULE_DESCRIPTION("Driver for SGI SN special memory operations");
420 MODULE_LICENSE("GPL");