mirror of
https://github.com/AetherDroid/android_kernel_samsung_on5xelte.git
synced 2025-09-07 08:48:05 -04:00
66 lines
1.6 KiB
C
66 lines
1.6 KiB
C
/*
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* SCSI library functions depending on DMA
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*/
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#include <linux/blkdev.h>
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#include <linux/device.h>
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#include <linux/export.h>
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#include <linux/kernel.h>
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#include <scsi/scsi.h>
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#include <scsi/scsi_cmnd.h>
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#include <scsi/scsi_device.h>
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#include <scsi/scsi_host.h>
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static struct dma_attrs scsi_direct_attrs;
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/**
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* scsi_dma_map - perform DMA mapping against command's sg lists
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* @cmd: scsi command
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*
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* Returns the number of sg lists actually used, zero if the sg lists
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* is NULL, or -ENOMEM if the mapping failed.
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*/
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int scsi_dma_map(struct scsi_cmnd *cmd)
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{
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int nseg = 0;
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struct dma_attrs *attrs = &scsi_direct_attrs;
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if (scsi_sg_count(cmd)) {
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struct device *dev = cmd->device->host->dma_dev;
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if (dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
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attrs = (cmd->request->cmd_flags & REQ_KERNEL) ?
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&scsi_direct_attrs : NULL;
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nseg = dma_map_sg_attr(dev, scsi_sglist(cmd),scsi_sg_count(cmd), cmd->sc_data_direction, attrs);
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if (unlikely(!nseg))
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return -ENOMEM;
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}
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return nseg;
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}
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EXPORT_SYMBOL(scsi_dma_map);
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/**
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* scsi_dma_unmap - unmap command's sg lists mapped by scsi_dma_map
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* @cmd: scsi command
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*/
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void scsi_dma_unmap(struct scsi_cmnd *cmd)
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{
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if (scsi_sg_count(cmd)) {
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struct device *dev = cmd->device->host->dma_dev;
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dma_unmap_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
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cmd->sc_data_direction);
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}
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}
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EXPORT_SYMBOL(scsi_dma_unmap);
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/**
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* scsi_dma_set_skip_cpu_sync - skip operations for cache coherency
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*/
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void scsi_dma_set_skip_cpu_sync(void)
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{
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init_dma_attrs(&scsi_direct_attrs);
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dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &scsi_direct_attrs);
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}
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EXPORT_SYMBOL(scsi_dma_set_skip_cpu_sync);
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