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charset="utf-8" This will add usb_alloc_noncoherent() and usb_free_noncoherent() functions to support alloc and free buffer in a dma-noncoherent way. To explicit manage the memory ownership for the kernel and device, this will also add usb_dma_noncoherent_sync_for_cpu/device() functions and call it at proper time. The management requires the user save sg_table returned by usb_alloc_noncoherent() to urb->sgt. Signed-off-by: Xu Yang Reviewed-by: Alan Stern --- Changes in v5: - improve if-else logic again Changes in v4: - improve if-else logic Changes in v3: - put Return section at the end of description - correct some abbreviations - remove usb_dma_noncoherent_sync_for_cpu() and usb_dma_noncoherent_sync_for_device() - do DMA sync in usb_hcd_map_urb_for_dma() and usb_hcd_unmap_urb_for_dma() - call flush_kernel_vmap_range() for OUT transfers and invalidate_kernel_vmap_range() for IN transfers --- drivers/usb/core/hcd.c | 29 ++++++++++----- drivers/usb/core/usb.c | 80 ++++++++++++++++++++++++++++++++++++++++++ include/linux/usb.h | 11 ++++++ 3 files changed, 112 insertions(+), 8 deletions(-) diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index c22de97432a0..03771bbc6c01 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -1342,29 +1342,35 @@ void usb_hcd_unmap_urb_for_dma(struct usb_hcd *hcd,= struct urb *urb) =20 dir =3D usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE; if (IS_ENABLED(CONFIG_HAS_DMA) && - (urb->transfer_flags & URB_DMA_MAP_SG)) + (urb->transfer_flags & URB_DMA_MAP_SG)) { dma_unmap_sg(hcd->self.sysdev, urb->sg, urb->num_sgs, dir); - else if (IS_ENABLED(CONFIG_HAS_DMA) && - (urb->transfer_flags & URB_DMA_MAP_PAGE)) + } else if (IS_ENABLED(CONFIG_HAS_DMA) && + (urb->transfer_flags & URB_DMA_MAP_PAGE)) { dma_unmap_page(hcd->self.sysdev, urb->transfer_dma, urb->transfer_buffer_length, dir); - else if (IS_ENABLED(CONFIG_HAS_DMA) && - (urb->transfer_flags & URB_DMA_MAP_SINGLE)) + } else if (IS_ENABLED(CONFIG_HAS_DMA) && + (urb->transfer_flags & URB_DMA_MAP_SINGLE)) { dma_unmap_single(hcd->self.sysdev, urb->transfer_dma, urb->transfer_buffer_length, dir); - else if (urb->transfer_flags & URB_MAP_LOCAL) + } else if (urb->transfer_flags & URB_MAP_LOCAL) { hcd_free_coherent(urb->dev->bus, &urb->transfer_dma, &urb->transfer_buffer, urb->transfer_buffer_length, dir); + } else if ((urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP) && urb->sgt) { + dma_sync_sgtable_for_cpu(hcd->self.sysdev, urb->sgt, dir); + if (dir =3D=3D DMA_FROM_DEVICE) + invalidate_kernel_vmap_range(urb->transfer_buffer, + urb->transfer_buffer_length); + } =20 /* Make it safe to call this routine more than once */ urb->transfer_flags &=3D ~(URB_DMA_MAP_SG | URB_DMA_MAP_PAGE | @@ -1425,8 +1431,15 @@ int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, str= uct urb *urb, } =20 dir =3D usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE; - if (urb->transfer_buffer_length !=3D 0 - && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) { + if (urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP) { + if (!urb->sgt) + return 0; + + if (dir =3D=3D DMA_TO_DEVICE) + flush_kernel_vmap_range(urb->transfer_buffer, + urb->transfer_buffer_length); + dma_sync_sgtable_for_device(hcd->self.sysdev, urb->sgt, dir); + } else if (urb->transfer_buffer_length !=3D 0) { if (hcd->localmem_pool) { ret =3D hcd_alloc_coherent( urb->dev->bus, mem_flags, diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index 118fa4c93a79..fca7735fc660 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -1030,6 +1030,86 @@ void usb_free_coherent(struct usb_device *dev, size_= t size, void *addr, } EXPORT_SYMBOL_GPL(usb_free_coherent); =20 +/** + * usb_alloc_noncoherent - allocate dma-noncoherent buffer for URB_NO_xxx_= DMA_MAP + * @dev: device the buffer will be used with + * @size: requested buffer size + * @mem_flags: affect whether allocation may block + * @dma: used to return DMA address of buffer + * @dir: DMA transfer direction + * @table: used to return sg_table of allocated memory + * + * To explicit manage the memory ownership for the kernel vs the device by + * USB core, the user needs save sg_table to urb->sgt. Then USB core will + * do DMA sync for CPU and device properly. + * + * When the buffer is no longer used, free it with usb_free_noncoherent(). + * + * Return: Either null (indicating no buffer could be allocated), or the + * cpu-space pointer to a buffer that may be used to perform DMA to the + * specified device. Such cpu-space buffers are returned along with the D= MA + * address (through the pointer provided). + */ +void *usb_alloc_noncoherent(struct usb_device *dev, size_t size, + gfp_t mem_flags, dma_addr_t *dma, + enum dma_data_direction dir, + struct sg_table **table) +{ + struct device *dmadev; + struct sg_table *sgt; + void *buffer; + + if (!dev || !dev->bus) + return NULL; + + dmadev =3D bus_to_hcd(dev->bus)->self.sysdev; + + sgt =3D dma_alloc_noncontiguous(dmadev, size, dir, mem_flags, 0); + if (!sgt) + return NULL; + + buffer =3D dma_vmap_noncontiguous(dmadev, size, sgt); + if (!buffer) { + dma_free_noncontiguous(dmadev, size, sgt, dir); + return NULL; + } + + *table =3D sgt; + *dma =3D sg_dma_address(sgt->sgl); + + return buffer; +} +EXPORT_SYMBOL_GPL(usb_alloc_noncoherent); + +/** + * usb_free_noncoherent - free memory allocated with usb_alloc_noncoherent= () + * @dev: device the buffer was used with + * @size: requested buffer size + * @addr: CPU address of buffer + * @dir: DMA transfer direction + * @table: describe the allocated and DMA mapped memory, + * + * This reclaims an I/O buffer, letting it be reused. The memory must have + * been allocated using usb_alloc_noncoherent(), and the parameters must m= atch + * those provided in that allocation request. + */ +void usb_free_noncoherent(struct usb_device *dev, size_t size, + void *addr, enum dma_data_direction dir, + struct sg_table *table) +{ + struct device *dmadev; + + if (!dev || !dev->bus) + return; + if (!addr) + return; + + dmadev =3D bus_to_hcd(dev->bus)->self.sysdev; + dma_vunmap_noncontiguous(dmadev, addr); + dma_free_noncontiguous(dmadev, size, table, dir); +} +EXPORT_SYMBOL_GPL(usb_free_noncoherent); + /* * Notifications of device and interface registration */ diff --git a/include/linux/usb.h b/include/linux/usb.h index e8662843e68c..9ade441ab4c8 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -1619,6 +1619,7 @@ struct urb { void *transfer_buffer; /* (in) associated data buffer */ dma_addr_t transfer_dma; /* (in) dma addr for transfer_buffer */ struct scatterlist *sg; /* (in) scatter gather buffer list */ + struct sg_table *sgt; /* (in) scatter gather table for noncoherent buffe= r */ int num_mapped_sgs; /* (internal) mapped sg entries */ int num_sgs; /* (in) number of entries in the sg list */ u32 transfer_buffer_length; /* (in) data buffer length */ @@ -1824,6 +1825,16 @@ void *usb_alloc_coherent(struct usb_device *dev, siz= e_t size, void usb_free_coherent(struct usb_device *dev, size_t size, void *addr, dma_addr_t dma); =20 +enum dma_data_direction; + +void *usb_alloc_noncoherent(struct usb_device *dev, size_t size, + gfp_t mem_flags, dma_addr_t *dma, + enum dma_data_direction dir, + struct sg_table **table); +void usb_free_noncoherent(struct usb_device *dev, size_t size, + void *addr, enum dma_data_direction dir, + struct sg_table *table); + /*-------------------------------------------------------------------* * SYNCHRONOUS CALL SUPPORT * *-------------------------------------------------------------------*/ --=20 2.34.1