cregit-Linux how code gets into the kernel

Release 4.7 drivers/media/pci/ivtv/ivtv-udma.c

/*
    User DMA

    Copyright (C) 2003-2004  Kevin Thayer <nufan_wfk at yahoo.com>
    Copyright (C) 2004  Chris Kennedy <c@groovy.org>
    Copyright (C) 2005-2007  Hans Verkuil <hverkuil@xs4all.nl>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "ivtv-driver.h"
#include "ivtv-udma.h"


void ivtv_udma_get_page_info(struct ivtv_dma_page_info *dma_page, unsigned long first, unsigned long size) { dma_page->uaddr = first & PAGE_MASK; dma_page->offset = first & ~PAGE_MASK; dma_page->tail = 1 + ((first+size-1) & ~PAGE_MASK); dma_page->first = (first & PAGE_MASK) >> PAGE_SHIFT; dma_page->last = ((first+size-1) & PAGE_MASK) >> PAGE_SHIFT; dma_page->page_count = dma_page->last - dma_page->first + 1; if (dma_page->page_count == 1) dma_page->tail -= dma_page->offset; }

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int ivtv_udma_fill_sg_list (struct ivtv_user_dma *dma, struct ivtv_dma_page_info *dma_page, int map_offset) { int i, offset; unsigned long flags; if (map_offset < 0) return map_offset; offset = dma_page->offset; /* Fill SG Array with new values */ for (i = 0; i < dma_page->page_count; i++) { unsigned int len = (i == dma_page->page_count - 1) ? dma_page->tail : PAGE_SIZE - offset; if (PageHighMem(dma->map[map_offset])) { void *src; if (dma->bouncemap[map_offset] == NULL) dma->bouncemap[map_offset] = alloc_page(GFP_KERNEL); if (dma->bouncemap[map_offset] == NULL) return -1; local_irq_save(flags); src = kmap_atomic(dma->map[map_offset]) + offset; memcpy(page_address(dma->bouncemap[map_offset]) + offset, src, len); kunmap_atomic(src); local_irq_restore(flags); sg_set_page(&dma->SGlist[map_offset], dma->bouncemap[map_offset], len, offset); } else { sg_set_page(&dma->SGlist[map_offset], dma->map[map_offset], len, offset); } offset = 0; map_offset++; } return map_offset; }

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void ivtv_udma_fill_sg_array (struct ivtv_user_dma *dma, u32 buffer_offset, u32 buffer_offset_2, u32 split) { int i; struct scatterlist *sg; for (i = 0, sg = dma->SGlist; i < dma->SG_length; i++, sg = sg_next(sg)) { dma->SGarray[i].size = cpu_to_le32(sg_dma_len(sg)); dma->SGarray[i].src = cpu_to_le32(sg_dma_address(sg)); dma->SGarray[i].dst = cpu_to_le32(buffer_offset); buffer_offset += sg_dma_len(sg); split -= sg_dma_len(sg); if (split == 0) buffer_offset = buffer_offset_2; } }

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/* User DMA Buffers */
void ivtv_udma_alloc(struct ivtv *itv) { if (itv->udma.SG_handle == 0) { /* Map DMA Page Array Buffer */ itv->udma.SG_handle = pci_map_single(itv->pdev, itv->udma.SGarray, sizeof(itv->udma.SGarray), PCI_DMA_TODEVICE); ivtv_udma_sync_for_cpu(itv); } }

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int ivtv_udma_setup(struct ivtv *itv, unsigned long ivtv_dest_addr, void __user *userbuf, int size_in_bytes) { struct ivtv_dma_page_info user_dma; struct ivtv_user_dma *dma = &itv->udma; int i, err; IVTV_DEBUG_DMA("ivtv_udma_setup, dst: 0x%08x\n", (unsigned int)ivtv_dest_addr); /* Still in USE */ if (dma->SG_length || dma->page_count) { IVTV_DEBUG_WARN("ivtv_udma_setup: SG_length %d page_count %d still full?\n", dma->SG_length, dma->page_count); return -EBUSY; } ivtv_udma_get_page_info(&user_dma, (unsigned long)userbuf, size_in_bytes); if (user_dma.page_count <= 0) { IVTV_DEBUG_WARN("ivtv_udma_setup: Error %d page_count from %d bytes %d offset\n", user_dma.page_count, size_in_bytes, user_dma.offset); return -EINVAL; } /* Get user pages for DMA Xfer */ err = get_user_pages_unlocked(user_dma.uaddr, user_dma.page_count, 0, 1, dma->map); if (user_dma.page_count != err) { IVTV_DEBUG_WARN("failed to map user pages, returned %d instead of %d\n", err, user_dma.page_count); if (err >= 0) { for (i = 0; i < err; i++) put_page(dma->map[i]); return -EINVAL; } return err; } dma->page_count = user_dma.page_count; /* Fill SG List with new values */ if (ivtv_udma_fill_sg_list(dma, &user_dma, 0) < 0) { for (i = 0; i < dma->page_count; i++) { put_page(dma->map[i]); } dma->page_count = 0; return -ENOMEM; } /* Map SG List */ dma->SG_length = pci_map_sg(itv->pdev, dma->SGlist, dma->page_count, PCI_DMA_TODEVICE); /* Fill SG Array with new values */ ivtv_udma_fill_sg_array (dma, ivtv_dest_addr, 0, -1); /* Tag SG Array with Interrupt Bit */ dma->SGarray[dma->SG_length - 1].size |= cpu_to_le32(0x80000000); ivtv_udma_sync_for_device(itv); return dma->page_count; }

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void ivtv_udma_unmap(struct ivtv *itv) { struct ivtv_user_dma *dma = &itv->udma; int i; IVTV_DEBUG_INFO("ivtv_unmap_user_dma\n"); /* Nothing to free */ if (dma->page_count == 0) return; /* Unmap Scatterlist */ if (dma->SG_length) { pci_unmap_sg(itv->pdev, dma->SGlist, dma->page_count, PCI_DMA_TODEVICE); dma->SG_length = 0; } /* sync DMA */ ivtv_udma_sync_for_cpu(itv); /* Release User Pages */ for (i = 0; i < dma->page_count; i++) { put_page(dma->map[i]); } dma->page_count = 0; }

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void ivtv_udma_free(struct ivtv *itv) { int i; /* Unmap SG Array */ if (itv->udma.SG_handle) { pci_unmap_single(itv->pdev, itv->udma.SG_handle, sizeof(itv->udma.SGarray), PCI_DMA_TODEVICE); } /* Unmap Scatterlist */ if (itv->udma.SG_length) { pci_unmap_sg(itv->pdev, itv->udma.SGlist, itv->udma.page_count, PCI_DMA_TODEVICE); } for (i = 0; i < IVTV_DMA_SG_OSD_ENT; i++) { if (itv->udma.bouncemap[i]) __free_page(itv->udma.bouncemap[i]); } }

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void ivtv_udma_start(struct ivtv *itv) { IVTV_DEBUG_DMA("start UDMA\n"); write_reg(itv->udma.SG_handle, IVTV_REG_DECDMAADDR); write_reg_sync(read_reg(IVTV_REG_DMAXFER) | 0x01, IVTV_REG_DMAXFER); set_bit(IVTV_F_I_DMA, &itv->i_flags); set_bit(IVTV_F_I_UDMA, &itv->i_flags); clear_bit(IVTV_F_I_UDMA_PENDING, &itv->i_flags); }

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void ivtv_udma_prepare(struct ivtv *itv) { unsigned long flags; spin_lock_irqsave(&itv->dma_reg_lock, flags); if (!test_bit(IVTV_F_I_DMA, &itv->i_flags)) ivtv_udma_start(itv); else set_bit(IVTV_F_I_UDMA_PENDING, &itv->i_flags); spin_unlock_irqrestore(&itv->dma_reg_lock, flags); }

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