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 = kzalloc(sizeof(struct page *) * acd->page_count, GFP_KERNEL);
  70         if (!acd->user_pages) {
  71                 dev_err(&priv->ldev->pldev->dev, "Couldn't kmalloc space for for the page pointers\n");
  72                 rv = -ENOMEM;
  73                 goto err_alloc_userpages;
  74         }
  75
  76         // Lock the user buffer pages in memory, and hold on to the page pointers (for the sglist)
  77         down_read(&current->mm->mmap_sem);      /*  get memory map semaphore */
  78         rv = get_user_pages(iov_base, acd->page_count, FOLL_TOUCH | FOLL_WRITE | FOLL_GET, acd->user_pages, NULL);
  79         up_read(&current->mm->mmap_sem);        /*  release the semaphore */
  80         if (rv != acd->page_count) {
  81                 dev_err(&priv->ldev->pldev->dev, "Couldn't get_user_pages (%ld)\n", rv);
  82                 goto err_get_user_pages;
  83         }
  84
  85         // Allocate and setup the sg_table (scatterlist entries)
  86         rv = sg_alloc_table_from_pages(&acd->sgt, acd->user_pages, acd->page_count, iov_base & (PAGE_SIZE-1), iov_len, GFP_KERNEL);
  87         if (rv) {
  88                 dev_err(&priv->ldev->pldev->dev, "Couldn't alloc sg_table (%ld)\n", rv);
  89                 goto err_alloc_sg_table;
  90         }
  91
  92         // Setup the DMA mapping for all the sg entries
  93         acd->mapped_entry_count = dma_map_sg(&ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, ldev->dir);
  94         if (acd->mapped_entry_count <= 0) {
  95                 dev_err(&priv->ldev->pldev->dev, "Couldn't dma_map_sg (%d)\n", acd->mapped_entry_count);
  96                 goto err_dma_map_sg;
  97         }
  98
  99         // Calculate how many descriptors are actually needed for this transfer.
 100         for_each_sg(acd->sgt.sgl, sg, acd->mapped_entry_count, i) {
 101                 desc_needed += count_parts_for_sge(sg);
 102         }
 103
 104         lock_engine(ldev);
 105
 106         // Figoure out how many descriptors are available and return an error if there aren't enough
 107         num_descrs_avail = count_descriptors_available(ldev);
 108         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);
 109         if (desc_needed >= ldev->desc_pool_cnt) {
 110                 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);
 111                 rv = -EAGAIN;
 112                 goto err_descr_too_many;
 113         }
 114         if (desc_needed > num_descrs_avail) {
 115                 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);
 116                 rv = -EMSGSIZE;
 117                 goto err_descr_too_many;
 118         }
 119
 120         // Loop through all the sg table entries and fill out a descriptor for each one.
 121         desc = ldev->desc_next;
 122         card_addr = acd->priv->card_addr;
 123         for_each_sg(acd->sgt.sgl, sg, acd->mapped_entry_count, i) {
 124                 pcnt = count_parts_for_sge(sg);
 125                 for (p = 0 ; p < pcnt ; p++) {
 126                         // Fill out the descriptor
 127                         BUG_ON(desc == NULL);
 128                         clear_desc(desc);
 129                         if (p != pcnt-1) {
 130                                 desc->DescByteCount = 0x80000;
 131                         } else {
 132                                 desc->DescByteCount = sg_dma_len(sg) - (p * 0x80000);
 133                         }
 134                         desc->DescBufferByteCount = desc->DescByteCount;
 135
 136                         desc->DescControlFlags |= DMA_DESC_CTL_IRQONERR;
 137                         if (i == 0 && p == 0)
 138                                 desc->DescControlFlags |= DMA_DESC_CTL_SOP;
 139                         if (i == acd->mapped_entry_count-1 && p == pcnt-1)
 140                                 desc->DescControlFlags |= DMA_DESC_CTL_EOP | DMA_DESC_CTL_IRQONDONE;
 141
 142                         desc->DescCardAddrLS = (card_addr & 0xFFFFFFFF);
 143                         desc->DescCardAddrMS = (card_addr >> 32) & 0xF;
 144                         card_addr += desc->DescByteCount;
 145
 146                         dma_addr  = sg_dma_address(sg) + (p * 0x80000);
 147                         desc->DescSystemAddrLS = (dma_addr & 0x00000000FFFFFFFFUL) >>  0;
 148                         desc->DescSystemAddrMS = (dma_addr & 0xFFFFFFFF00000000UL) >> 32;
 149
 150                         user_ctl = acd->priv->user_ctl;
 151                         if (i == acd->mapped_entry_count-1 && p == pcnt-1) {
 152                                 user_ctl = acd->priv->user_ctl_last;
 153                         }
 154                         desc->DescUserControlLS = (user_ctl & 0x00000000FFFFFFFFUL) >>  0;
 155                         desc->DescUserControlMS = (user_ctl & 0xFFFFFFFF00000000UL) >> 32;
 156
 157                         if (i == acd->mapped_entry_count-1 && p == pcnt-1)
 158                                 desc->acd = acd;
 159
 160                         dev_dbg(&priv->ldev->pldev->dev, "  Filled descriptor %p (acd = %p)\n", desc, desc->acd);
 161
 162                         ldev->desc_next = desc->Next;
 163                         desc = desc->Next;
 164                 }
 165         }
 166
 167         // Send the filled descriptors off to the hardware to process!
 168         SetEngineSWPtr(ldev, ldev->desc_next);
 169
 170         unlock_engine(ldev);
 171
 172         rv = wait_for_completion_interruptible(&done);
 173         /*
 174          * If the user aborted (rv == -ERESTARTSYS), we're no longer responsible
 175          * for cleaning up the acd
 176          */
 177         if (rv == -ERESTARTSYS)
 178                 acd->cpl = NULL;
 179         if (rv == 0) {
 180                 rv = acd->len;
 181                 kfree(acd);
 182         }
 183         return rv;
 184
 185  err_descr_too_many:
 186         unlock_engine(ldev);
 187         dma_unmap_sg(&ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, ldev->dir);
 188         sg_free_table(&acd->sgt);
 189  err_dma_map_sg:
 190  err_alloc_sg_table:
 191         for (i = 0 ; i < acd->page_count ; i++) {
 192                 put_page(acd->user_pages[i]);
 193         }
 194  err_get_user_pages:
 195         kfree(acd->user_pages);
 196  err_alloc_userpages:
 197         kfree(acd);
 198         dev_dbg(&priv->ldev->pldev->dev, "%s returning with error %ld\n", __func__, rv);
 199         return rv;
 200 }
 201
 202 void  transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags)
 203 {
 204         unsigned int i;
 205
 206         BUG_ON(acd == NULL);
 207         BUG_ON(acd->user_pages == NULL);
 208         BUG_ON(acd->sgt.sgl == NULL);
 209         BUG_ON(acd->ldev == NULL);
 210         BUG_ON(acd->ldev->pldev == NULL);
 211
 212         for (i = 0 ; i < acd->page_count ; i++) {
 213                 if (!PageReserved(acd->user_pages[i])) {
 214                         set_page_dirty(acd->user_pages[i]);
 215                 }
 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
 224         sg_free_table(&acd->sgt);
 225
 226         kfree(acd->user_pages);
 227
 228         acd->flags = flags;
 229
 230         if (acd->cpl) {
 231                 complete(acd->cpl);
 232         } else {
 233                 /*
 234                  * There's no completion, so we're responsible for cleaning up
 235                  * the acd
 236                  */
 237                 kfree(acd);
 238         }
 239 }
 240
 241 /**********  Fileops  **********/
 242 static
 243 int  kpc_dma_open(struct inode *inode, struct file *filp)
 244 {
 245         struct dev_private_data *priv;
 246         struct kpc_dma_device *ldev = kpc_dma_lookup_device(iminor(inode));
 247
 248         if (!ldev)
 249                 return -ENODEV;
 250
 251         if (!atomic_dec_and_test(&ldev->open_count)) {
 252                 atomic_inc(&ldev->open_count);
 253                 return -EBUSY; /* already open */
 254         }
 255
 256         priv = kzalloc(sizeof(struct dev_private_data), GFP_KERNEL);
 257         if (!priv)
 258                 return -ENOMEM;
 259
 260         priv->ldev = ldev;
 261         filp->private_data = priv;
 262
 263         return 0;
 264 }
 265
 266 static
 267 int  kpc_dma_close(struct inode *inode, struct file *filp)
 268 {
 269         struct kpc_dma_descriptor *cur;
 270         struct dev_private_data *priv = (struct dev_private_data *)filp->private_data;
 271         struct kpc_dma_device *eng = priv->ldev;
 272
 273         lock_engine(eng);
 274
 275         stop_dma_engine(eng);
 276
 277         cur = eng->desc_completed->Next;
 278         while (cur != eng->desc_next) {
 279                 dev_dbg(&eng->pldev->dev, "Aborting descriptor %p (acd = %p)\n", cur, cur->acd);
 280                 if (cur->DescControlFlags & DMA_DESC_CTL_EOP) {
 281                         if (cur->acd)
 282                                 transfer_complete_cb(cur->acd, 0, ACD_FLAG_ABORT);
 283                 }
 284
 285                 clear_desc(cur);
 286                 eng->desc_completed = cur;
 287
 288                 cur = cur->Next;
 289         }
 290
 291         start_dma_engine(eng);
 292
 293         unlock_engine(eng);
 294
 295         atomic_inc(&priv->ldev->open_count); /* release the device */
 296         kfree(priv);
 297         return 0;
 298 }
 299
 300 static
 301 ssize_t  kpc_dma_read(struct file *filp,       char __user *user_buf, size_t count, loff_t *ppos)
 302 {
 303         struct dev_private_data *priv = (struct dev_private_data *)filp->private_data;
 304
 305         if (priv->ldev->dir != DMA_FROM_DEVICE)
 306                 return -EMEDIUMTYPE;
 307
 308         return kpc_dma_transfer(priv, (unsigned long)user_buf, count);
 309 }
 310
 311 static
 312 ssize_t  kpc_dma_write(struct file *filp, const char __user *user_buf, size_t count, loff_t *ppos)
 313 {
 314         struct dev_private_data *priv = (struct dev_private_data *)filp->private_data;
 315
 316         if (priv->ldev->dir != DMA_TO_DEVICE)
 317                 return -EMEDIUMTYPE;
 318
 319         return kpc_dma_transfer(priv, (unsigned long)user_buf, count);
 320 }
 321
 322 static
 323 long  kpc_dma_ioctl(struct file *filp, unsigned int ioctl_num, unsigned long ioctl_param)
 324 {
 325         struct dev_private_data *priv = (struct dev_private_data *)filp->private_data;
 326
 327         switch (ioctl_num) {
 328         case KND_IOCTL_SET_CARD_ADDR:
 329                 priv->card_addr  = ioctl_param; return priv->card_addr;
 330         case KND_IOCTL_SET_USER_CTL:
 331                 priv->user_ctl   = ioctl_param; return priv->user_ctl;
 332         case KND_IOCTL_SET_USER_CTL_LAST:
 333                 priv->user_ctl_last = ioctl_param; return priv->user_ctl_last;
 334         case KND_IOCTL_GET_USER_STS:
 335                 return priv->user_sts;
 336         }
 337
 338         return -ENOTTY;
 339 }
 340
 341 const struct file_operations  kpc_dma_fops = {
 342         .owner      = THIS_MODULE,
 343         .open           = kpc_dma_open,
 344         .release        = kpc_dma_close,
 345         .read           = kpc_dma_read,
 346         .write          = kpc_dma_write,
 347         .unlocked_ioctl = kpc_dma_ioctl,
 348 };
 349