From b3476675320eda83cf061a686cdc80b76f2bfdc4 Mon Sep 17 00:00:00 2001 From: Magnus Damm Date: Wed, 23 Jan 2008 15:58:35 +0900 Subject: [PATCH] usb: dma bounce buffer support usb: dma bounce buffer support V4 This patch adds dma bounce buffer support to the usb core. These buffers can be enabled with the HCD_LOCAL_MEM flag, and they make sure that all data passed to the host controller is allocated using dma_alloc_coherent(). Signed-off-by: Magnus Damm Acked-by: Alan Stern Acked-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/buffer.c | 9 +- drivers/usb/core/hcd.c | 176 +++++++++++++++++++++++++++++++++----- drivers/usb/core/hcd.h | 1 + 3 files changed, 163 insertions(+), 23 deletions(-) diff --git a/drivers/usb/core/buffer.c b/drivers/usb/core/buffer.c index 28d4972f7ad..acd9f00a0b7 100644 --- a/drivers/usb/core/buffer.c +++ b/drivers/usb/core/buffer.c @@ -53,7 +53,8 @@ int hcd_buffer_create(struct usb_hcd *hcd) char name[16]; int i, size; - if (!hcd->self.controller->dma_mask) + if (!hcd->self.controller->dma_mask && + !(hcd->driver->flags & HCD_LOCAL_MEM)) return 0; for (i = 0; i < HCD_BUFFER_POOLS; i++) { @@ -107,7 +108,8 @@ void *hcd_buffer_alloc( int i; /* some USB hosts just use PIO */ - if (!bus->controller->dma_mask) { + if (!bus->controller->dma_mask && + !(hcd->driver->flags & HCD_LOCAL_MEM)) { *dma = ~(dma_addr_t) 0; return kmalloc(size, mem_flags); } @@ -132,7 +134,8 @@ void hcd_buffer_free( if (!addr) return; - if (!bus->controller->dma_mask) { + if (!bus->controller->dma_mask && + !(hcd->driver->flags & HCD_LOCAL_MEM)) { kfree(addr); return; } diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index 372372116bb..febd6b40da3 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include @@ -1112,48 +1113,177 @@ void usb_hcd_unlink_urb_from_ep(struct usb_hcd *hcd, struct urb *urb) } EXPORT_SYMBOL_GPL(usb_hcd_unlink_urb_from_ep); -static void map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb) +/* + * Some usb host controllers can only perform dma using a small SRAM area. + * The usb core itself is however optimized for host controllers that can dma + * using regular system memory - like pci devices doing bus mastering. + * + * To support host controllers with limited dma capabilites we provide dma + * bounce buffers. This feature can be enabled using the HCD_LOCAL_MEM flag. + * For this to work properly the host controller code must first use the + * function dma_declare_coherent_memory() to point out which memory area + * that should be used for dma allocations. + * + * The HCD_LOCAL_MEM flag then tells the usb code to allocate all data for + * dma using dma_alloc_coherent() which in turn allocates from the memory + * area pointed out with dma_declare_coherent_memory(). + * + * So, to summarize... + * + * - We need "local" memory, canonical example being + * a small SRAM on a discrete controller being the + * only memory that the controller can read ... + * (a) "normal" kernel memory is no good, and + * (b) there's not enough to share + * + * - The only *portable* hook for such stuff in the + * DMA framework is dma_declare_coherent_memory() + * + * - So we use that, even though the primary requirement + * is that the memory be "local" (hence addressible + * by that device), not "coherent". + * + */ + +static int hcd_alloc_coherent(struct usb_bus *bus, + gfp_t mem_flags, dma_addr_t *dma_handle, + void **vaddr_handle, size_t size, + enum dma_data_direction dir) +{ + unsigned char *vaddr; + + vaddr = hcd_buffer_alloc(bus, size + sizeof(vaddr), + mem_flags, dma_handle); + if (!vaddr) + return -ENOMEM; + + /* + * Store the virtual address of the buffer at the end + * of the allocated dma buffer. The size of the buffer + * may be uneven so use unaligned functions instead + * of just rounding up. It makes sense to optimize for + * memory footprint over access speed since the amount + * of memory available for dma may be limited. + */ + put_unaligned((unsigned long)*vaddr_handle, + (unsigned long *)(vaddr + size)); + + if (dir == DMA_TO_DEVICE) + memcpy(vaddr, *vaddr_handle, size); + + *vaddr_handle = vaddr; + return 0; +} + +static void hcd_free_coherent(struct usb_bus *bus, dma_addr_t *dma_handle, + void **vaddr_handle, size_t size, + enum dma_data_direction dir) +{ + unsigned char *vaddr = *vaddr_handle; + + vaddr = (void *)get_unaligned((unsigned long *)(vaddr + size)); + + if (dir == DMA_FROM_DEVICE) + memcpy(vaddr, *vaddr_handle, size); + + hcd_buffer_free(bus, size + sizeof(vaddr), *vaddr_handle, *dma_handle); + + *vaddr_handle = vaddr; + *dma_handle = 0; +} + +static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb, + gfp_t mem_flags) { + enum dma_data_direction dir; + int ret = 0; + /* Map the URB's buffers for DMA access. * Lower level HCD code should use *_dma exclusively, * unless it uses pio or talks to another transport. */ - if (hcd->self.uses_dma && !is_root_hub(urb->dev)) { - if (usb_endpoint_xfer_control(&urb->ep->desc) - && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) - urb->setup_dma = dma_map_single ( + if (is_root_hub(urb->dev)) + return 0; + + if (usb_endpoint_xfer_control(&urb->ep->desc) + && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) { + if (hcd->self.uses_dma) + urb->setup_dma = dma_map_single( hcd->self.controller, urb->setup_packet, - sizeof (struct usb_ctrlrequest), + sizeof(struct usb_ctrlrequest), DMA_TO_DEVICE); - if (urb->transfer_buffer_length != 0 - && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) + else if (hcd->driver->flags & HCD_LOCAL_MEM) + ret = hcd_alloc_coherent( + urb->dev->bus, mem_flags, + &urb->setup_dma, + (void **)&urb->setup_packet, + sizeof(struct usb_ctrlrequest), + DMA_TO_DEVICE); + } + + dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE; + if (ret == 0 && urb->transfer_buffer_length != 0 + && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) { + if (hcd->self.uses_dma) urb->transfer_dma = dma_map_single ( hcd->self.controller, urb->transfer_buffer, urb->transfer_buffer_length, - usb_urb_dir_in(urb) - ? DMA_FROM_DEVICE - : DMA_TO_DEVICE); + dir); + else if (hcd->driver->flags & HCD_LOCAL_MEM) { + ret = hcd_alloc_coherent( + urb->dev->bus, mem_flags, + &urb->transfer_dma, + &urb->transfer_buffer, + urb->transfer_buffer_length, + dir); + + if (ret && usb_endpoint_xfer_control(&urb->ep->desc) + && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) + hcd_free_coherent(urb->dev->bus, + &urb->setup_dma, + (void **)&urb->setup_packet, + sizeof(struct usb_ctrlrequest), + DMA_TO_DEVICE); + } } + return ret; } static void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb) { - if (hcd->self.uses_dma && !is_root_hub(urb->dev)) { - if (usb_endpoint_xfer_control(&urb->ep->desc) - && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) + enum dma_data_direction dir; + + if (is_root_hub(urb->dev)) + return; + + if (usb_endpoint_xfer_control(&urb->ep->desc) + && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) { + if (hcd->self.uses_dma) dma_unmap_single(hcd->self.controller, urb->setup_dma, sizeof(struct usb_ctrlrequest), DMA_TO_DEVICE); - if (urb->transfer_buffer_length != 0 - && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) + else if (hcd->driver->flags & HCD_LOCAL_MEM) + hcd_free_coherent(urb->dev->bus, &urb->setup_dma, + (void **)&urb->setup_packet, + sizeof(struct usb_ctrlrequest), + DMA_TO_DEVICE); + } + + dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE; + if (urb->transfer_buffer_length != 0 + && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) { + if (hcd->self.uses_dma) dma_unmap_single(hcd->self.controller, urb->transfer_dma, urb->transfer_buffer_length, - usb_urb_dir_in(urb) - ? DMA_FROM_DEVICE - : DMA_TO_DEVICE); + dir); + else if (hcd->driver->flags & HCD_LOCAL_MEM) + hcd_free_coherent(urb->dev->bus, &urb->transfer_dma, + &urb->transfer_buffer, + urb->transfer_buffer_length, + dir); } } @@ -1185,7 +1315,12 @@ int usb_hcd_submit_urb (struct urb *urb, gfp_t mem_flags) * URBs must be submitted in process context with interrupts * enabled. */ - map_urb_for_dma(hcd, urb); + status = map_urb_for_dma(hcd, urb, mem_flags); + if (unlikely(status)) { + usbmon_urb_submit_error(&hcd->self, urb, status); + goto error; + } + if (is_root_hub(urb->dev)) status = rh_urb_enqueue(hcd, urb); else @@ -1194,6 +1329,7 @@ int usb_hcd_submit_urb (struct urb *urb, gfp_t mem_flags) if (unlikely(status)) { usbmon_urb_submit_error(&hcd->self, urb, status); unmap_urb_for_dma(hcd, urb); + error: urb->hcpriv = NULL; INIT_LIST_HEAD(&urb->urb_list); atomic_dec(&urb->use_count); diff --git a/drivers/usb/core/hcd.h b/drivers/usb/core/hcd.h index 080298ad599..0095641c51f 100644 --- a/drivers/usb/core/hcd.h +++ b/drivers/usb/core/hcd.h @@ -165,6 +165,7 @@ struct hc_driver { int flags; #define HCD_MEMORY 0x0001 /* HC regs use memory (else I/O) */ +#define HCD_LOCAL_MEM 0x0002 /* HC needs local memory */ #define HCD_USB11 0x0010 /* USB 1.1 */ #define HCD_USB2 0x0020 /* USB 2.0 */ -- 2.41.1