arch/s390/include/asm/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/errno.h>
  17 #include <linux/err.h>
  18 #include <linux/types.h>
  19 #include <linux/slab.h>
  20 #include <asm/cio.h>
  21 #include <asm/uaccess.h>
  22
  23 #ifdef __s390x__
  24 #define IDA_SIZE_LOG 12 /* 11 for 2k , 12 for 4k */
  25 #else
  26 #define IDA_SIZE_LOG 11 /* 11 for 2k , 12 for 4k */
  27 #endif
  28 #define IDA_BLOCK_SIZE (1L<<IDA_SIZE_LOG)
  29
  30 /*
  31  * Test if an address/length pair needs an idal list.
  32  */
  33 static inline int
  34 idal_is_needed(void *vaddr, unsigned int length)
  35 {
  36 #ifdef __s390x__
  37         return ((__pa(vaddr) + length - 1) >> 31) != 0;
  38 #else
  39         return 0;
  40 #endif
  41 }
  42
  43
  44 /*
  45  * Return the number of idal words needed for an address/length pair.
  46  */
  47 static inline unsigned int idal_nr_words(void *vaddr, unsigned int length)
  48 {
  49         return ((__pa(vaddr) & (IDA_BLOCK_SIZE-1)) + length +
  50                 (IDA_BLOCK_SIZE-1)) >> IDA_SIZE_LOG;
  51 }
  52
  53 /*
  54  * Create the list of idal words for an address/length pair.
  55  */
  56 static inline unsigned long *idal_create_words(unsigned long *idaws,
  57                                                void *vaddr, unsigned int length)
  58 {
  59         unsigned long paddr;
  60         unsigned int cidaw;
  61
  62         paddr = __pa(vaddr);
  63         cidaw = ((paddr & (IDA_BLOCK_SIZE-1)) + length +
  64                  (IDA_BLOCK_SIZE-1)) >> IDA_SIZE_LOG;
  65         *idaws++ = paddr;
  66         paddr &= -IDA_BLOCK_SIZE;
  67         while (--cidaw > 0) {
  68                 paddr += IDA_BLOCK_SIZE;
  69                 *idaws++ = paddr;
  70         }
  71         return idaws;
  72 }
  73
  74 /*
  75  * Sets the address of the data in CCW.
  76  * If necessary it allocates an IDAL and sets the appropriate flags.
  77  */
  78 static inline int
  79 set_normalized_cda(struct ccw1 * ccw, void *vaddr)
  80 {
  81 #ifdef __s390x__
  82         unsigned int nridaws;
  83         unsigned long *idal;
  84
  85         if (ccw->flags & CCW_FLAG_IDA)
  86                 return -EINVAL;
  87         nridaws = idal_nr_words(vaddr, ccw->count);
  88         if (nridaws > 0) {
  89                 idal = kmalloc(nridaws * sizeof(unsigned long),
  90                                GFP_ATOMIC | GFP_DMA );
  91                 if (idal == NULL)
  92                         return -ENOMEM;
  93                 idal_create_words(idal, vaddr, ccw->count);
  94                 ccw->flags |= CCW_FLAG_IDA;
  95                 vaddr = idal;
  96         }
  97 #endif
  98         ccw->cda = (__u32)(unsigned long) vaddr;
  99         return 0;
 100 }
 101
 102 /*
 103  * Releases any allocated IDAL related to the CCW.
 104  */
 105 static inline void
 106 clear_normalized_cda(struct ccw1 * ccw)
 107 {
 108 #ifdef __s390x__
 109         if (ccw->flags & CCW_FLAG_IDA) {
 110                 kfree((void *)(unsigned long) ccw->cda);
 111                 ccw->flags &= ~CCW_FLAG_IDA;
 112         }
 113 #endif
 114         ccw->cda = 0;
 115 }
 116
 117 /*
 118  * Idal buffer extension
 119  */
 120 struct idal_buffer {
 121         size_t size;
 122         size_t page_order;
 123         void *data[0];
 124 };
 125
 126 /*
 127  * Allocate an idal buffer
 128  */
 129 static inline struct idal_buffer *
 130 idal_buffer_alloc(size_t size, int page_order)
 131 {
 132         struct idal_buffer *ib;
 133         int nr_chunks, nr_ptrs, i;
 134
 135         nr_ptrs = (size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_LOG;
 136         nr_chunks = (4096 << page_order) >> IDA_SIZE_LOG;
 137         ib = kmalloc(sizeof(struct idal_buffer) + nr_ptrs*sizeof(void *),
 138                      GFP_DMA | GFP_KERNEL);
 139         if (ib == NULL)
 140                 return ERR_PTR(-ENOMEM);
 141         ib->size = size;
 142         ib->page_order = page_order;
 143         for (i = 0; i < nr_ptrs; i++) {
 144                 if ((i & (nr_chunks - 1)) != 0) {
 145                         ib->data[i] = ib->data[i-1] + IDA_BLOCK_SIZE;
 146                         continue;
 147                 }
 148                 ib->data[i] = (void *)
 149                         __get_free_pages(GFP_KERNEL, page_order);
 150                 if (ib->data[i] != NULL)
 151                         continue;
 152                 // Not enough memory
 153                 while (i >= nr_chunks) {
 154                         i -= nr_chunks;
 155                         free_pages((unsigned long) ib->data[i],
 156                                    ib->page_order);
 157                 }
 158                 kfree(ib);
 159                 return ERR_PTR(-ENOMEM);
 160         }
 161         return ib;
 162 }
 163
 164 /*
 165  * Free an idal buffer.
 166  */
 167 static inline void
 168 idal_buffer_free(struct idal_buffer *ib)
 169 {
 170         int nr_chunks, nr_ptrs, i;
 171
 172         nr_ptrs = (ib->size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_LOG;
 173         nr_chunks = (4096 << ib->page_order) >> IDA_SIZE_LOG;
 174         for (i = 0; i < nr_ptrs; i += nr_chunks)
 175                 free_pages((unsigned long) ib->data[i], ib->page_order);
 176         kfree(ib);
 177 }
 178
 179 /*
 180  * Test if a idal list is really needed.
 181  */
 182 static inline int
 183 __idal_buffer_is_needed(struct idal_buffer *ib)
 184 {
 185 #ifdef __s390x__
 186         return ib->size > (4096ul << ib->page_order) ||
 187                 idal_is_needed(ib->data[0], ib->size);
 188 #else
 189         return ib->size > (4096ul << ib->page_order);
 190 #endif
 191 }
 192
 193 /*
 194  * Set channel data address to idal buffer.
 195  */
 196 static inline void
 197 idal_buffer_set_cda(struct idal_buffer *ib, struct ccw1 *ccw)
 198 {
 199         if (__idal_buffer_is_needed(ib)) {
 200                 // setup idals;
 201                 ccw->cda = (u32)(addr_t) ib->data;
 202                 ccw->flags |= CCW_FLAG_IDA;
 203         } else
 204                 // we do not need idals - use direct addressing
 205                 ccw->cda = (u32)(addr_t) ib->data[0];
 206         ccw->count = ib->size;
 207 }
 208
 209 /*
 210  * Copy count bytes from an idal buffer to user memory
 211  */
 212 static inline size_t
 213 idal_buffer_to_user(struct idal_buffer *ib, void __user *to, size_t count)
 214 {
 215         size_t left;
 216         int i;
 217
 218         BUG_ON(count > ib->size);
 219         for (i = 0; count > IDA_BLOCK_SIZE; i++) {
 220                 left = copy_to_user(to, ib->data[i], IDA_BLOCK_SIZE);
 221                 if (left)
 222                         return left + count - IDA_BLOCK_SIZE;
 223                 to = (void __user *) to + IDA_BLOCK_SIZE;
 224                 count -= IDA_BLOCK_SIZE;
 225         }
 226         return copy_to_user(to, ib->data[i], count);
 227 }
 228
 229 /*
 230  * Copy count bytes from user memory to an idal buffer
 231  */
 232 static inline size_t
 233 idal_buffer_from_user(struct idal_buffer *ib, const void __user *from, size_t count)
 234 {
 235         size_t left;
 236         int i;
 237
 238         BUG_ON(count > ib->size);
 239         for (i = 0; count > IDA_BLOCK_SIZE; i++) {
 240                 left = copy_from_user(ib->data[i], from, IDA_BLOCK_SIZE);
 241                 if (left)
 242                         return left + count - IDA_BLOCK_SIZE;
 243                 from = (void __user *) from + IDA_BLOCK_SIZE;
 244                 count -= IDA_BLOCK_SIZE;
 245         }
 246         return copy_from_user(ib->data[i], from, count);
 247 }
 248
 249 #endif