pci/ivtv/ivtv-udma.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003     User DMA
0004
0005     Copyright (C) 2003-2004  Kevin Thayer <nufan_wfk at yahoo.com>
0006     Copyright (C) 2004  Chris Kennedy <c@groovy.org>
0007     Copyright (C) 2005-2007  Hans Verkuil <hverkuil@xs4all.nl>
0008
0009  */
0010
0011 #include "ivtv-driver.h"
0012 #include "ivtv-udma.h"
0013
0014 void ivtv_udma_get_page_info(struct ivtv_dma_page_info *dma_page, unsigned long first, unsigned long size)
0015 {
0016     dma_page->uaddr = first & PAGE_MASK;
0017     dma_page->offset = first & ~PAGE_MASK;
0018     dma_page->tail = 1 + ((first+size-1) & ~PAGE_MASK);
0019     dma_page->first = (first & PAGE_MASK) >> PAGE_SHIFT;
0020     dma_page->last = ((first+size-1) & PAGE_MASK) >> PAGE_SHIFT;
0021     dma_page->page_count = dma_page->last - dma_page->first + 1;
0022     if (dma_page->page_count == 1) dma_page->tail -= dma_page->offset;
0023 }
0024
0025 int ivtv_udma_fill_sg_list (struct ivtv_user_dma *dma, struct ivtv_dma_page_info *dma_page, int map_offset)
0026 {
0027     int i, offset;
0028     unsigned long flags;
0029
0030     if (map_offset < 0)
0031         return map_offset;
0032
0033     offset = dma_page->offset;
0034
0035     /* Fill SG Array with new values */
0036     for (i = 0; i < dma_page->page_count; i++) {
0037         unsigned int len = (i == dma_page->page_count - 1) ?
0038             dma_page->tail : PAGE_SIZE - offset;
0039
0040         if (PageHighMem(dma->map[map_offset])) {
0041             void *src;
0042
0043             if (dma->bouncemap[map_offset] == NULL)
0044                 dma->bouncemap[map_offset] = alloc_page(GFP_KERNEL);
0045             if (dma->bouncemap[map_offset] == NULL)
0046                 return -1;
0047             local_irq_save(flags);
0048             src = kmap_atomic(dma->map[map_offset]) + offset;
0049             memcpy(page_address(dma->bouncemap[map_offset]) + offset, src, len);
0050             kunmap_atomic(src);
0051             local_irq_restore(flags);
0052             sg_set_page(&dma->SGlist[map_offset], dma->bouncemap[map_offset], len, offset);
0053         }
0054         else {
0055             sg_set_page(&dma->SGlist[map_offset], dma->map[map_offset], len, offset);
0056         }
0057         offset = 0;
0058         map_offset++;
0059     }
0060     return map_offset;
0061 }
0062
0063 void ivtv_udma_fill_sg_array (struct ivtv_user_dma *dma, u32 buffer_offset, u32 buffer_offset_2, u32 split) {
0064     int i;
0065     struct scatterlist *sg;
0066
0067     for_each_sg(dma->SGlist, sg, dma->SG_length, i) {
0068         dma->SGarray[i].size = cpu_to_le32(sg_dma_len(sg));
0069         dma->SGarray[i].src = cpu_to_le32(sg_dma_address(sg));
0070         dma->SGarray[i].dst = cpu_to_le32(buffer_offset);
0071         buffer_offset += sg_dma_len(sg);
0072
0073         split -= sg_dma_len(sg);
0074         if (split == 0)
0075             buffer_offset = buffer_offset_2;
0076     }
0077 }
0078
0079 /* User DMA Buffers */
0080 void ivtv_udma_alloc(struct ivtv *itv)
0081 {
0082     if (itv->udma.SG_handle == 0) {
0083         /* Map DMA Page Array Buffer */
0084         itv->udma.SG_handle = dma_map_single(&itv->pdev->dev,
0085                              itv->udma.SGarray,
0086                              sizeof(itv->udma.SGarray),
0087                              DMA_TO_DEVICE);
0088         ivtv_udma_sync_for_cpu(itv);
0089     }
0090 }
0091
0092 int ivtv_udma_setup(struct ivtv *itv, unsigned long ivtv_dest_addr,
0093                void __user *userbuf, int size_in_bytes)
0094 {
0095     struct ivtv_dma_page_info user_dma;
0096     struct ivtv_user_dma *dma = &itv->udma;
0097     int err;
0098
0099     IVTV_DEBUG_DMA("ivtv_udma_setup, dst: 0x%08x\n", (unsigned int)ivtv_dest_addr);
0100
0101     /* Still in USE */
0102     if (dma->SG_length || dma->page_count) {
0103         IVTV_DEBUG_WARN("ivtv_udma_setup: SG_length %d page_count %d still full?\n",
0104                dma->SG_length, dma->page_count);
0105         return -EBUSY;
0106     }
0107
0108     ivtv_udma_get_page_info(&user_dma, (unsigned long)userbuf, size_in_bytes);
0109
0110     if (user_dma.page_count <= 0) {
0111         IVTV_DEBUG_WARN("ivtv_udma_setup: Error %d page_count from %d bytes %d offset\n",
0112                user_dma.page_count, size_in_bytes, user_dma.offset);
0113         return -EINVAL;
0114     }
0115
0116     /* Pin user pages for DMA Xfer */
0117     err = pin_user_pages_unlocked(user_dma.uaddr, user_dma.page_count,
0118             dma->map, FOLL_FORCE);
0119
0120     if (user_dma.page_count != err) {
0121         IVTV_DEBUG_WARN("failed to map user pages, returned %d instead of %d\n",
0122                err, user_dma.page_count);
0123         if (err >= 0) {
0124             unpin_user_pages(dma->map, err);
0125             return -EINVAL;
0126         }
0127         return err;
0128     }
0129
0130     dma->page_count = user_dma.page_count;
0131
0132     /* Fill SG List with new values */
0133     if (ivtv_udma_fill_sg_list(dma, &user_dma, 0) < 0) {
0134         unpin_user_pages(dma->map, dma->page_count);
0135         dma->page_count = 0;
0136         return -ENOMEM;
0137     }
0138
0139     /* Map SG List */
0140     dma->SG_length = dma_map_sg(&itv->pdev->dev, dma->SGlist,
0141                     dma->page_count, DMA_TO_DEVICE);
0142
0143     /* Fill SG Array with new values */
0144     ivtv_udma_fill_sg_array (dma, ivtv_dest_addr, 0, -1);
0145
0146     /* Tag SG Array with Interrupt Bit */
0147     dma->SGarray[dma->SG_length - 1].size |= cpu_to_le32(0x80000000);
0148
0149     ivtv_udma_sync_for_device(itv);
0150     return dma->page_count;
0151 }
0152
0153 void ivtv_udma_unmap(struct ivtv *itv)
0154 {
0155     struct ivtv_user_dma *dma = &itv->udma;
0156
0157     IVTV_DEBUG_INFO("ivtv_unmap_user_dma\n");
0158
0159     /* Nothing to free */
0160     if (dma->page_count == 0)
0161         return;
0162
0163     /* Unmap Scatterlist */
0164     if (dma->SG_length) {
0165         dma_unmap_sg(&itv->pdev->dev, dma->SGlist, dma->page_count,
0166                  DMA_TO_DEVICE);
0167         dma->SG_length = 0;
0168     }
0169     /* sync DMA */
0170     ivtv_udma_sync_for_cpu(itv);
0171
0172     unpin_user_pages(dma->map, dma->page_count);
0173     dma->page_count = 0;
0174 }
0175
0176 void ivtv_udma_free(struct ivtv *itv)
0177 {
0178     int i;
0179
0180     /* Unmap SG Array */
0181     if (itv->udma.SG_handle) {
0182         dma_unmap_single(&itv->pdev->dev, itv->udma.SG_handle,
0183                  sizeof(itv->udma.SGarray), DMA_TO_DEVICE);
0184     }
0185
0186     /* Unmap Scatterlist */
0187     if (itv->udma.SG_length) {
0188         dma_unmap_sg(&itv->pdev->dev, itv->udma.SGlist,
0189                  itv->udma.page_count, DMA_TO_DEVICE);
0190     }
0191
0192     for (i = 0; i < IVTV_DMA_SG_OSD_ENT; i++) {
0193         if (itv->udma.bouncemap[i])
0194             __free_page(itv->udma.bouncemap[i]);
0195     }
0196 }
0197
0198 void ivtv_udma_start(struct ivtv *itv)
0199 {
0200     IVTV_DEBUG_DMA("start UDMA\n");
0201     write_reg(itv->udma.SG_handle, IVTV_REG_DECDMAADDR);
0202     write_reg_sync(read_reg(IVTV_REG_DMAXFER) | 0x01, IVTV_REG_DMAXFER);
0203     set_bit(IVTV_F_I_DMA, &itv->i_flags);
0204     set_bit(IVTV_F_I_UDMA, &itv->i_flags);
0205     clear_bit(IVTV_F_I_UDMA_PENDING, &itv->i_flags);
0206 }
0207
0208 void ivtv_udma_prepare(struct ivtv *itv)
0209 {
0210     unsigned long flags;
0211
0212     spin_lock_irqsave(&itv->dma_reg_lock, flags);
0213     if (!test_bit(IVTV_F_I_DMA, &itv->i_flags))
0214         ivtv_udma_start(itv);
0215     else
0216         set_bit(IVTV_F_I_UDMA_PENDING, &itv->i_flags);
0217     spin_unlock_irqrestore(&itv->dma_reg_lock, flags);
0218 }