include/asm-s390/idals.h

   1 /*
   2  * File...........: linux/include/asm-s390x/idals.h
   3  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
   4  *                  Martin Schwidefsky <schwidefsky@de.ibm.com>
   5  * Bugreports.to..: <Linux390@de.ibm.com>
   6  * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 2000a
   7
   8  * History of changes
   9  * 07/24/00 new file
  10  * 05/04/02 code restructuring.
  11  */
  12
  13 #ifndef _S390_IDALS_H
  14 #define _S390_IDALS_H
  15
  16 #include <linux/config.h>
  17 #include <linux/errno.h>
  18 #include <linux/err.h>
  19 #include <linux/types.h>
  20 #include <linux/slab.h>
  21 #include <asm/cio.h>
  22 #include <asm/uaccess.h>
  23
  24 #ifdef __s390x__
  25 #define IDA_SIZE_LOG 12 /* 11 for 2k , 12 for 4k */
  26 #else
  27 #define IDA_SIZE_LOG 11 /* 11 for 2k , 12 for 4k */
  28 #endif
  29 #define IDA_BLOCK_SIZE (1L<<IDA_SIZE_LOG)
  30
  31 /*
  32  * Test if an address/length pair needs an idal list.
  33  */
  34 static inline int
  35 idal_is_needed(void *vaddr, unsigned int length)
  36 {
  37 #ifdef __s390x__
  38         return ((__pa(vaddr) + length - 1) >> 31) != 0;
  39 #else
  40         return 0;
  41 #endif
  42 }
  43
  44
  45 /*
  46  * Return the number of idal words needed for an address/length pair.
  47  */
  48 static inline unsigned int
  49 idal_nr_words(void *vaddr, unsigned int length)
  50 {
  51 #ifdef __s390x__
  52         if (idal_is_needed(vaddr, length))
  53                 return ((__pa(vaddr) & (IDA_BLOCK_SIZE-1)) + length +
  54                         (IDA_BLOCK_SIZE-1)) >> IDA_SIZE_LOG;
  55 #endif
  56         return 0;
  57 }
  58
  59 /*
  60  * Create the list of idal words for an address/length pair.
  61  */
  62 static inline unsigned long *
  63 idal_create_words(unsigned long *idaws, void *vaddr, unsigned int length)
  64 {
  65 #ifdef __s390x__
  66         unsigned long paddr;
  67         unsigned int cidaw;
  68
  69         paddr = __pa(vaddr);
  70         cidaw = ((paddr & (IDA_BLOCK_SIZE-1)) + length +
  71                  (IDA_BLOCK_SIZE-1)) >> IDA_SIZE_LOG;
  72         *idaws++ = paddr;
  73         paddr &= -IDA_BLOCK_SIZE;
  74         while (--cidaw > 0) {
  75                 paddr += IDA_BLOCK_SIZE;
  76                 *idaws++ = paddr;
  77         }
  78 #endif
  79         return idaws;
  80 }
  81
  82 /*
  83  * Sets the address of the data in CCW.
  84  * If necessary it allocates an IDAL and sets the appropriate flags.
  85  */
  86 static inline int
  87 set_normalized_cda(struct ccw1 * ccw, void *vaddr)
  88 {
  89 #ifdef __s390x__
  90         unsigned int nridaws;
  91         unsigned long *idal;
  92
  93         if (ccw->flags & CCW_FLAG_IDA)
  94                 return -EINVAL;
  95         nridaws = idal_nr_words(vaddr, ccw->count);
  96         if (nridaws > 0) {
  97                 idal = kmalloc(nridaws * sizeof(unsigned long),
  98                                GFP_ATOMIC | GFP_DMA );
  99                 if (idal == NULL)
 100                         return -ENOMEM;
 101                 idal_create_words(idal, vaddr, ccw->count);
 102                 ccw->flags |= CCW_FLAG_IDA;
 103                 vaddr = idal;
 104         }
 105 #endif
 106         ccw->cda = (__u32)(unsigned long) vaddr;
 107         return 0;
 108 }
 109
 110 /*
 111  * Releases any allocated IDAL related to the CCW.
 112  */
 113 static inline void
 114 clear_normalized_cda(struct ccw1 * ccw)
 115 {
 116 #ifdef __s390x__
 117         if (ccw->flags & CCW_FLAG_IDA) {
 118                 kfree((void *)(unsigned long) ccw->cda);
 119                 ccw->flags &= ~CCW_FLAG_IDA;
 120         }
 121 #endif
 122         ccw->cda = 0;
 123 }
 124
 125 /*
 126  * Idal buffer extension
 127  */
 128 struct idal_buffer {
 129         size_t size;
 130         size_t page_order;
 131         void *data[0];
 132 };
 133
 134 /*
 135  * Allocate an idal buffer
 136  */
 137 static inline struct idal_buffer *
 138 idal_buffer_alloc(size_t size, int page_order)
 139 {
 140         struct idal_buffer *ib;
 141         int nr_chunks, nr_ptrs, i;
 142
 143         nr_ptrs = (size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_LOG;
 144         nr_chunks = (4096 << page_order) >> IDA_SIZE_LOG;
 145         ib = kmalloc(sizeof(struct idal_buffer) + nr_ptrs*sizeof(void *),
 146                      GFP_DMA | GFP_KERNEL);
 147         if (ib == NULL)
 148                 return ERR_PTR(-ENOMEM);
 149         ib->size = size;
 150         ib->page_order = page_order;
 151         for (i = 0; i < nr_ptrs; i++) {
 152                 if ((i & (nr_chunks - 1)) != 0) {
 153                         ib->data[i] = ib->data[i-1] + IDA_BLOCK_SIZE;
 154                         continue;
 155                 }
 156                 ib->data[i] = (void *)
 157                         __get_free_pages(GFP_KERNEL, page_order);
 158                 if (ib->data[i] != NULL)
 159                         continue;
 160                 // Not enough memory
 161                 while (i >= nr_chunks) {
 162                         i -= nr_chunks;
 163                         free_pages((unsigned long) ib->data[i],
 164                                    ib->page_order);
 165                 }
 166                 kfree(ib);
 167                 return ERR_PTR(-ENOMEM);
 168         }
 169         return ib;
 170 }
 171
 172 /*
 173  * Free an idal buffer.
 174  */
 175 static inline void
 176 idal_buffer_free(struct idal_buffer *ib)
 177 {
 178         int nr_chunks, nr_ptrs, i;
 179
 180         nr_ptrs = (ib->size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_LOG;
 181         nr_chunks = (4096 << ib->page_order) >> IDA_SIZE_LOG;
 182         for (i = 0; i < nr_ptrs; i += nr_chunks)
 183                 free_pages((unsigned long) ib->data[i], ib->page_order);
 184         kfree(ib);
 185 }
 186
 187 /*
 188  * Test if a idal list is really needed.
 189  */
 190 static inline int
 191 __idal_buffer_is_needed(struct idal_buffer *ib)
 192 {
 193 #ifdef __s390x__
 194         return ib->size > (4096ul << ib->page_order) ||
 195                 idal_is_needed(ib->data[0], ib->size);
 196 #else
 197         return ib->size > (4096ul << ib->page_order);
 198 #endif
 199 }
 200
 201 /*
 202  * Set channel data address to idal buffer.
 203  */
 204 static inline void
 205 idal_buffer_set_cda(struct idal_buffer *ib, struct ccw1 *ccw)
 206 {
 207         if (__idal_buffer_is_needed(ib)) {
 208                 // setup idals;
 209                 ccw->cda = (u32)(addr_t) ib->data;
 210                 ccw->flags |= CCW_FLAG_IDA;
 211         } else
 212                 // we do not need idals - use direct addressing
 213                 ccw->cda = (u32)(addr_t) ib->data[0];
 214         ccw->count = ib->size;
 215 }
 216
 217 /*
 218  * Copy count bytes from an idal buffer to user memory
 219  */
 220 static inline size_t
 221 idal_buffer_to_user(struct idal_buffer *ib, void __user *to, size_t count)
 222 {
 223         size_t left;
 224         int i;
 225
 226         BUG_ON(count > ib->size);
 227         for (i = 0; count > IDA_BLOCK_SIZE; i++) {
 228                 left = copy_to_user(to, ib->data[i], IDA_BLOCK_SIZE);
 229                 if (left)
 230                         return left + count - IDA_BLOCK_SIZE;
 231                 to = (void __user *) to + IDA_BLOCK_SIZE;
 232                 count -= IDA_BLOCK_SIZE;
 233         }
 234         return copy_to_user(to, ib->data[i], count);
 235 }
 236
 237 /*
 238  * Copy count bytes from user memory to an idal buffer
 239  */
 240 static inline size_t
 241 idal_buffer_from_user(struct idal_buffer *ib, const void __user *from, size_t count)
 242 {
 243         size_t left;
 244         int i;
 245
 246         BUG_ON(count > ib->size);
 247         for (i = 0; count > IDA_BLOCK_SIZE; i++) {
 248                 left = copy_from_user(ib->data[i], from, IDA_BLOCK_SIZE);
 249                 if (left)
 250                         return left + count - IDA_BLOCK_SIZE;
 251                 from = (void __user *) from + IDA_BLOCK_SIZE;
 252                 count -= IDA_BLOCK_SIZE;
 253         }
 254         return copy_from_user(ib->data[i], from, count);
 255 }
 256
 257 #endif