drivers/staging/kpc2000/kpc_dma/fileops.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 #include <linux/module.h>
   3 #include <linux/init.h>
   4 #include <linux/mm.h>
   5 #include <linux/kernel.h>   /* printk() */
   6 #include <linux/slab.h>     /* kmalloc() */
   7 #include <linux/fs.h>       /* everything... */
   8 #include <linux/errno.h>    /* error codes */
   9 #include <linux/types.h>    /* size_t */
  10 #include <linux/cdev.h>
  11 #include <linux/uaccess.h>  /* copy_*_user */
  12 #include <linux/highmem.h>
  13 #include <linux/pagemap.h>
  14 #include "kpc_dma_driver.h"
  15 #include "uapi.h"
  16
  17 /**********  Helper Functions  **********/
  18 static inline
  19 unsigned int  count_pages(unsigned long iov_base, size_t iov_len)
  20 {
  21         unsigned long first = (iov_base                 & PAGE_MASK) >> PAGE_SHIFT;
  22         unsigned long last  = ((iov_base + iov_len - 1) & PAGE_MASK) >> PAGE_SHIFT;
  23
  24         return last - first + 1;
  25 }
  26
  27 static inline
  28 unsigned int  count_parts_for_sge(struct scatterlist *sg)
  29 {
  30         return DIV_ROUND_UP(sg_dma_len(sg), 0x80000);
  31 }
  32
  33 /**********  Transfer Helpers  **********/
  34 static int kpc_dma_transfer(struct dev_private_data *priv,
  35                             unsigned long iov_base, size_t iov_len)
  36 {
  37         unsigned int i = 0;
  38         long rv = 0;
  39         struct kpc_dma_device *ldev;
  40         struct aio_cb_data *acd;
  41         DECLARE_COMPLETION_ONSTACK(done);
  42         u32 desc_needed = 0;
  43         struct scatterlist *sg;
  44         u32 num_descrs_avail;
  45         struct kpc_dma_descriptor *desc;
  46         unsigned int pcnt;
  47         unsigned int p;
  48         u64 card_addr;
  49         u64 dma_addr;
  50         u64 user_ctl;
  51
  52         ldev = priv->ldev;
  53
  54         acd = kzalloc(sizeof(*acd), GFP_KERNEL);
  55         if (!acd) {
  56                 dev_err(&priv->ldev->pldev->dev, "Couldn't kmalloc space for for the aio data\n");
  57                 return -ENOMEM;
  58         }
  59         memset(acd, 0x66, sizeof(struct aio_cb_data));
  60
  61         acd->priv = priv;
  62         acd->ldev = priv->ldev;
  63         acd->cpl = &done;
  64         acd->flags = 0;
  65         acd->len = iov_len;
  66         acd->page_count = count_pages(iov_base, iov_len);
  67
  68         // Allocate an array of page pointers
  69         acd->user_pages = kcalloc(acd->page_count, sizeof(struct page *),
  70                                   GFP_KERNEL);
  71         if (!acd->user_pages) {
  72                 dev_err(&priv->ldev->pldev->dev, "Couldn't kmalloc space for for the page pointers\n");
  73                 rv = -ENOMEM;
  74                 goto err_alloc_userpages;
  75         }
  76
  77         // Lock the user buffer pages in memory, and hold on to the page pointers (for the sglist)
  78         down_read(&current->mm->mmap_sem);      /*  get memory map semaphore */
  79         rv = get_user_pages(iov_base, acd->page_count, FOLL_TOUCH | FOLL_WRITE | FOLL_GET, acd->user_pages, NULL);
  80         up_read(&current->mm->mmap_sem);        /*  release the semaphore */
  81         if (rv != acd->page_count) {
  82                 dev_err(&priv->ldev->pldev->dev, "Couldn't get_user_pages (%ld)\n", rv);
  83                 goto err_get_user_pages;
  84         }
  85
  86         // Allocate and setup the sg_table (scatterlist entries)
  87         rv = sg_alloc_table_from_pages(&acd->sgt, acd->user_pages, acd->page_count, iov_base & (PAGE_SIZE - 1), iov_len, GFP_KERNEL);
  88         if (rv) {
  89                 dev_err(&priv->ldev->pldev->dev, "Couldn't alloc sg_table (%ld)\n", rv);
  90                 goto err_alloc_sg_table;
  91         }
  92
  93         // Setup the DMA mapping for all the sg entries
  94         acd->mapped_entry_count = dma_map_sg(&ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, ldev->dir);
  95         if (acd->mapped_entry_count <= 0) {
  96                 dev_err(&priv->ldev->pldev->dev, "Couldn't dma_map_sg (%d)\n", acd->mapped_entry_count);
  97                 goto err_dma_map_sg;
  98         }
  99
 100         // Calculate how many descriptors are actually needed for this transfer.
 101         for_each_sg(acd->sgt.sgl, sg, acd->mapped_entry_count, i) {
 102                 desc_needed += count_parts_for_sge(sg);
 103         }
 104
 105         lock_engine(ldev);
 106
 107         // Figoure out how many descriptors are available and return an error if there aren't enough
 108         num_descrs_avail = count_descriptors_available(ldev);
 109         dev_dbg(&priv->ldev->pldev->dev, "    mapped_entry_count = %d    num_descrs_needed = %d    num_descrs_avail = %d\n", acd->mapped_entry_count, desc_needed, num_descrs_avail);
 110         if (desc_needed >= ldev->desc_pool_cnt) {
 111                 dev_warn(&priv->ldev->pldev->dev, "    mapped_entry_count = %d    num_descrs_needed = %d    num_descrs_avail = %d    TOO MANY to ever complete!\n", acd->mapped_entry_count, desc_needed, num_descrs_avail);
 112                 rv = -EAGAIN;
 113                 goto err_descr_too_many;
 114         }
 115         if (desc_needed > num_descrs_avail) {
 116                 dev_warn(&priv->ldev->pldev->dev, "    mapped_entry_count = %d    num_descrs_needed = %d    num_descrs_avail = %d    Too many to complete right now.\n", acd->mapped_entry_count, desc_needed, num_descrs_avail);
 117                 rv = -EMSGSIZE;
 118                 goto err_descr_too_many;
 119         }
 120
 121         // Loop through all the sg table entries and fill out a descriptor for each one.
 122         desc = ldev->desc_next;
 123         card_addr = acd->priv->card_addr;
 124         for_each_sg(acd->sgt.sgl, sg, acd->mapped_entry_count, i) {
 125                 pcnt = count_parts_for_sge(sg);
 126                 for (p = 0 ; p < pcnt ; p++) {
 127                         // Fill out the descriptor
 128                         BUG_ON(!desc);
 129                         clear_desc(desc);
 130                         if (p != pcnt - 1)
 131                                 desc->DescByteCount = 0x80000;
 132                         else
 133                                 desc->DescByteCount = sg_dma_len(sg) - (p * 0x80000);
 134
 135                         desc->DescBufferByteCount = desc->DescByteCount;
 136
 137                         desc->DescControlFlags |= DMA_DESC_CTL_IRQONERR;
 138                         if (i == 0 && p == 0)
 139                                 desc->DescControlFlags |= DMA_DESC_CTL_SOP;
 140                         if (i == acd->mapped_entry_count - 1 && p == pcnt - 1)
 141                                 desc->DescControlFlags |= DMA_DESC_CTL_EOP | DMA_DESC_CTL_IRQONDONE;
 142
 143                         desc->DescCardAddrLS = (card_addr & 0xFFFFFFFF);
 144                         desc->DescCardAddrMS = (card_addr >> 32) & 0xF;
 145                         card_addr += desc->DescByteCount;
 146
 147                         dma_addr  = sg_dma_address(sg) + (p * 0x80000);
 148                         desc->DescSystemAddrLS = (dma_addr & 0x00000000FFFFFFFFUL) >>  0;
 149                         desc->DescSystemAddrMS = (dma_addr & 0xFFFFFFFF00000000UL) >> 32;
 150
 151                         user_ctl = acd->priv->user_ctl;
 152                         if (i == acd->mapped_entry_count - 1 && p == pcnt - 1)
 153                                 user_ctl = acd->priv->user_ctl_last;
 154
 155                         desc->DescUserControlLS = (user_ctl & 0x00000000FFFFFFFFUL) >>  0;
 156                         desc->DescUserControlMS = (user_ctl & 0xFFFFFFFF00000000UL) >> 32;
 157
 158                         if (i == acd->mapped_entry_count - 1 && p == pcnt - 1)
 159                                 desc->acd = acd;
 160
 161                         dev_dbg(&priv->ldev->pldev->dev, "  Filled descriptor %p (acd = %p)\n", desc, desc->acd);
 162
 163                         ldev->desc_next = desc->Next;
 164                         desc = desc->Next;
 165                 }
 166         }
 167
 168         // Send the filled descriptors off to the hardware to process!
 169         SetEngineSWPtr(ldev, ldev->desc_next);
 170
 171         unlock_engine(ldev);
 172
 173         rv = wait_for_completion_interruptible(&done);
 174         /*
 175          * If the user aborted (rv == -ERESTARTSYS), we're no longer responsible
 176          * for cleaning up the acd
 177          */
 178         if (rv == -ERESTARTSYS)
 179                 acd->cpl = NULL;
 180         if (rv == 0) {
 181                 rv = acd->len;
 182                 kfree(acd);
 183         }
 184         return rv;
 185
 186  err_descr_too_many:
 187         unlock_engine(ldev);
 188         dma_unmap_sg(&ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, ldev->dir);
 189         sg_free_table(&acd->sgt);
 190  err_dma_map_sg:
 191  err_alloc_sg_table:
 192         for (i = 0 ; i < acd->page_count ; i++)
 193                 put_page(acd->user_pages[i]);
 194
 195  err_get_user_pages:
 196         kfree(acd->user_pages);
 197  err_alloc_userpages:
 198         kfree(acd);
 199         dev_dbg(&priv->ldev->pldev->dev, "%s returning with error %ld\n", __func__, rv);
 200         return rv;
 201 }
 202
 203 void  transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags)
 204 {
 205         unsigned int i;
 206
 207         BUG_ON(!acd);
 208         BUG_ON(!acd->user_pages);
 209         BUG_ON(!acd->sgt.sgl);
 210         BUG_ON(!acd->ldev);
 211         BUG_ON(!acd->ldev->pldev);
 212
 213         for (i = 0 ; i < acd->page_count ; i++) {
 214                 if (!PageReserved(acd->user_pages[i]))
 215                         set_page_dirty(acd->user_pages[i]);
 216         }
 217
 218         dma_unmap_sg(&acd->ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, acd->ldev->dir);
 219
 220         for (i = 0 ; i < acd->page_count ; i++)
 221                 put_page(acd->user_pages[i]);
 222
 223         sg_free_table(&acd->sgt);
 224
 225         kfree(acd->user_pages);
 226
 227         acd->flags = flags;
 228
 229         if (acd->cpl) {
 230                 complete(acd->cpl);
 231         } else {
 232                 /*
 233                  * There's no completion, so we're responsible for cleaning up
 234                  * the acd
 235                  */
 236                 kfree(acd);
 237         }
 238 }
 239
 240 /**********  Fileops  **********/
 241 static
 242 int  kpc_dma_open(struct inode *inode, struct file *filp)
 243 {
 244         struct dev_private_data *priv;
 245         struct kpc_dma_device *ldev = kpc_dma_lookup_device(iminor(inode));
 246
 247         if (!ldev)
 248                 return -ENODEV;
 249
 250         if (!atomic_dec_and_test(&ldev->open_count)) {
 251                 atomic_inc(&ldev->open_count);
 252                 return -EBUSY; /* already open */
 253         }
 254
 255         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 256         if (!priv)
 257                 return -ENOMEM;
 258
 259         priv->ldev = ldev;
 260         filp->private_data = priv;
 261
 262         return 0;
 263 }
 264
 265 static
 266 int  kpc_dma_close(struct inode *inode, struct file *filp)
 267 {
 268         struct kpc_dma_descriptor *cur;
 269         struct dev_private_data *priv = (struct dev_private_data *)filp->private_data;
 270         struct kpc_dma_device *eng = priv->ldev;
 271
 272         lock_engine(eng);
 273
 274         stop_dma_engine(eng);
 275
 276         cur = eng->desc_completed->Next;
 277         while (cur != eng->desc_next) {
 278                 dev_dbg(&eng->pldev->dev, "Aborting descriptor %p (acd = %p)\n", cur, cur->acd);
 279                 if (cur->DescControlFlags & DMA_DESC_CTL_EOP) {
 280                         if (cur->acd)
 281                                 transfer_complete_cb(cur->acd, 0, ACD_FLAG_ABORT);
 282                 }
 283
 284                 clear_desc(cur);
 285                 eng->desc_completed = cur;
 286
 287                 cur = cur->Next;
 288         }
 289
 290         start_dma_engine(eng);
 291
 292         unlock_engine(eng);
 293
 294         atomic_inc(&priv->ldev->open_count); /* release the device */
 295         kfree(priv);
 296         return 0;
 297 }
 298
 299 static
 300 ssize_t  kpc_dma_read(struct file *filp,       char __user *user_buf, size_t count, loff_t *ppos)
 301 {
 302         struct dev_private_data *priv = (struct dev_private_data *)filp->private_data;
 303
 304         if (priv->ldev->dir != DMA_FROM_DEVICE)
 305                 return -EMEDIUMTYPE;
 306
 307         return kpc_dma_transfer(priv, (unsigned long)user_buf, count);
 308 }
 309
 310 static
 311 ssize_t  kpc_dma_write(struct file *filp, const char __user *user_buf, size_t count, loff_t *ppos)
 312 {
 313         struct dev_private_data *priv = (struct dev_private_data *)filp->private_data;
 314
 315         if (priv->ldev->dir != DMA_TO_DEVICE)
 316                 return -EMEDIUMTYPE;
 317
 318         return kpc_dma_transfer(priv, (unsigned long)user_buf, count);
 319 }
 320
 321 static
 322 long  kpc_dma_ioctl(struct file *filp, unsigned int ioctl_num, unsigned long ioctl_param)
 323 {
 324         struct dev_private_data *priv = (struct dev_private_data *)filp->private_data;
 325
 326         switch (ioctl_num) {
 327         case KND_IOCTL_SET_CARD_ADDR:
 328                 priv->card_addr  = ioctl_param; return priv->card_addr;
 329         case KND_IOCTL_SET_USER_CTL:
 330                 priv->user_ctl   = ioctl_param; return priv->user_ctl;
 331         case KND_IOCTL_SET_USER_CTL_LAST:
 332                 priv->user_ctl_last = ioctl_param; return priv->user_ctl_last;
 333         case KND_IOCTL_GET_USER_STS:
 334                 return priv->user_sts;
 335         }
 336
 337         return -ENOTTY;
 338 }
 339
 340 const struct file_operations  kpc_dma_fops = {
 341         .owner      = THIS_MODULE,
 342         .open           = kpc_dma_open,
 343         .release        = kpc_dma_close,
 344         .read           = kpc_dma_read,
 345         .write          = kpc_dma_write,
 346         .unlocked_ioctl = kpc_dma_ioctl,
 347 };
 348