drivers/media/pci/ivtv/ivtv-udma.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
     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>

  */

 #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;
 }

 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;
 }

 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_each_sg(dma->SGlist, sg, dma->SG_length, i) {
 		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;
 	}
 }

 /* 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 = dma_map_single(&itv->pdev->dev,
 						     itv->udma.SGarray,
 						     sizeof(itv->udma.SGarray),
 						     DMA_TO_DEVICE);
 		ivtv_udma_sync_for_cpu(itv);
 	}
 }

 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 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;
 	}

 	/* Pin user pages for DMA Xfer */
 	err = pin_user_pages_unlocked(user_dma.uaddr, user_dma.page_count,
 			dma->map, 0);

 	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) {
 			unpin_user_pages(dma->map, err);
 			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) {
 		IVTV_DEBUG_WARN("%s: could not allocate bounce buffers for highmem userspace buffers\n",
 				__func__);
 		unpin_user_pages(dma->map, dma->page_count);
 		dma->page_count = 0;
 		return -ENOMEM;
 	}

 	/* Map SG List */
 	dma->SG_length = dma_map_sg(&itv->pdev->dev, dma->SGlist,
 				    dma->page_count, DMA_TO_DEVICE);
 	if (!dma->SG_length) {
 		IVTV_DEBUG_WARN("%s: DMA map error, SG_length is 0\n", __func__);
 		unpin_user_pages(dma->map, dma->page_count);
 		dma->page_count = 0;
 		return -EINVAL;
 	}

 	/* 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;
 }

 void ivtv_udma_unmap(struct ivtv *itv)
 {
 	struct ivtv_user_dma *dma = &itv->udma;

 	IVTV_DEBUG_INFO("ivtv_unmap_user_dma\n");

 	/* Nothing to free */
 	if (dma->page_count == 0)
 		return;

 	/* Unmap Scatterlist */
 	if (dma->SG_length) {
 		dma_unmap_sg(&itv->pdev->dev, dma->SGlist, dma->page_count,
 			     DMA_TO_DEVICE);
 		dma->SG_length = 0;
 	}
 	/* sync DMA */
 	ivtv_udma_sync_for_cpu(itv);

 	unpin_user_pages(dma->map, dma->page_count);
 	dma->page_count = 0;
 }

 void ivtv_udma_free(struct ivtv *itv)
 {
 	int i;

 	/* Unmap SG Array */
 	if (itv->udma.SG_handle) {
 		dma_unmap_single(&itv->pdev->dev, itv->udma.SG_handle,
 				 sizeof(itv->udma.SGarray), DMA_TO_DEVICE);
 	}

 	/* Unmap Scatterlist */
 	if (itv->udma.SG_length) {
 		dma_unmap_sg(&itv->pdev->dev, itv->udma.SGlist,
 			     itv->udma.page_count, DMA_TO_DEVICE);
 	}

 	for (i = 0; i < IVTV_DMA_SG_OSD_ENT; i++) {
 		if (itv->udma.bouncemap[i])
 			__free_page(itv->udma.bouncemap[i]);
 	}
 }

 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);
 }

 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);
 }
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	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>

	*/

	#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;
	}

	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;
	}

	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_each_sg(dma->SGlist, sg, dma->SG_length, i) {
	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;
	}
	}

	/* 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 = dma_map_single(&itv->pdev->dev,
	itv->udma.SGarray,
	sizeof(itv->udma.SGarray),
	DMA_TO_DEVICE);
	ivtv_udma_sync_for_cpu(itv);
	}
	}

	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 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;
	}

	/* Pin user pages for DMA Xfer */
	err = pin_user_pages_unlocked(user_dma.uaddr, user_dma.page_count,
	dma->map, 0);

	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) {
	unpin_user_pages(dma->map, err);
	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) {
	IVTV_DEBUG_WARN("%s: could not allocate bounce buffers for highmem userspace buffers\n",
	__func__);
	unpin_user_pages(dma->map, dma->page_count);
	dma->page_count = 0;
	return -ENOMEM;
	}

	/* Map SG List */
	dma->SG_length = dma_map_sg(&itv->pdev->dev, dma->SGlist,
	dma->page_count, DMA_TO_DEVICE);
	if (!dma->SG_length) {
	IVTV_DEBUG_WARN("%s: DMA map error, SG_length is 0\n", __func__);
	unpin_user_pages(dma->map, dma->page_count);
	dma->page_count = 0;
	return -EINVAL;
	}

	/* 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;
	}

	void ivtv_udma_unmap(struct ivtv *itv)
	{
	struct ivtv_user_dma *dma = &itv->udma;

	IVTV_DEBUG_INFO("ivtv_unmap_user_dma\n");

	/* Nothing to free */
	if (dma->page_count == 0)
	return;

	/* Unmap Scatterlist */
	if (dma->SG_length) {
	dma_unmap_sg(&itv->pdev->dev, dma->SGlist, dma->page_count,
	DMA_TO_DEVICE);
	dma->SG_length = 0;
	}
	/* sync DMA */
	ivtv_udma_sync_for_cpu(itv);

	unpin_user_pages(dma->map, dma->page_count);
	dma->page_count = 0;
	}

	void ivtv_udma_free(struct ivtv *itv)
	{
	int i;

	/* Unmap SG Array */
	if (itv->udma.SG_handle) {
	dma_unmap_single(&itv->pdev->dev, itv->udma.SG_handle,
	sizeof(itv->udma.SGarray), DMA_TO_DEVICE);
	}

	/* Unmap Scatterlist */
	if (itv->udma.SG_length) {
	dma_unmap_sg(&itv->pdev->dev, itv->udma.SGlist,
	itv->udma.page_count, DMA_TO_DEVICE);
	}

	for (i = 0; i < IVTV_DMA_SG_OSD_ENT; i++) {
	if (itv->udma.bouncemap[i])
	__free_page(itv->udma.bouncemap[i]);
	}
	}

	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);
	}

	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);
	}