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// SPDX-License-Identifier: GPL-2.0
* MUSB OTG driver DMA controller abstraction
* Copyright 2005 Mentor Graphics Corporation
* Copyright (C) 2005-2006 by Texas Instruments
* Copyright (C) 2006-2007 Nokia Corporation
#ifndef __MUSB_DMA_H__
#define __MUSB_DMA_H__
struct musb_hw_ep;
* DMA Controller Abstraction
* DMA Controllers are abstracted to allow use of a variety of different
* implementations of DMA, as allowed by the Inventra USB cores. On the
* host side, usbcore sets up the DMA mappings and flushes caches; on the
* peripheral side, the gadget controller driver does. Responsibilities
* of a DMA controller driver include:
* - Handling the details of moving multiple USB packets
* in cooperation with the Inventra USB core, including especially
* the correct RX side treatment of short packets and buffer-full
* states (both of which terminate transfers).
* - Knowing the correlation between dma channels and the
* Inventra core's local endpoint resources and data direction.
* - Maintaining a list of allocated/available channels.
* - Updating channel status on interrupts,
* whether shared with the Inventra core or separate.
#define DMA_ADDR_INVALID (~(dma_addr_t)0)
#define is_dma_capable() (0)
#define is_dma_capable() (1)
#define musb_dma_ux500(musb) (musb->ops->quirks & MUSB_DMA_UX500)
#define musb_dma_ux500(musb) 0
#define musb_dma_cppi41(musb) (musb->ops->quirks & MUSB_DMA_CPPI41)
#define musb_dma_cppi41(musb) 0
#define musb_dma_cppi(musb) (musb->ops->quirks & MUSB_DMA_CPPI)
#define musb_dma_cppi(musb) 0
#define tusb_dma_omap(musb) (musb->ops->quirks & MUSB_DMA_TUSB_OMAP)
#define tusb_dma_omap(musb) 0
#define musb_dma_inventra(musb) (musb->ops->quirks & MUSB_DMA_INVENTRA)
#define musb_dma_inventra(musb) 0
#if defined(CONFIG_USB_TI_CPPI_DMA) || defined(CONFIG_USB_TI_CPPI41_DMA)
#define is_cppi_enabled(musb) \
(musb_dma_cppi(musb) || musb_dma_cppi41(musb))
#define is_cppi_enabled(musb) 0
* DMA channel status ... updated by the dma controller driver whenever that
* status changes, and protected by the overall controller spinlock.
enum dma_channel_status {
/* unallocated */
/* allocated ... but not busy, no errors */
/* busy ... transactions are active */
/* transaction(s) aborted due to ... dma or memory bus error */
/* transaction(s) aborted due to ... core error or USB fault */
struct dma_controller;
* struct dma_channel - A DMA channel.
* @private_data: channel-private data
* @max_len: the maximum number of bytes the channel can move in one
* transaction (typically representing many USB maximum-sized packets)
* @actual_len: how many bytes have been transferred
* @status: current channel status (updated e.g. on interrupt)
* @desired_mode: true if mode 1 is desired; false if mode 0 is desired
* channels are associated with an endpoint for the duration of at least
* one usb transfer.
struct dma_channel {
void *private_data;
/* FIXME not void* private_data, but a dma_controller * */
size_t max_len;
size_t actual_len;
enum dma_channel_status status;
bool desired_mode;
bool rx_packet_done;
* dma_channel_status - return status of dma channel
* @c: the channel
* Returns the software's view of the channel status. If that status is BUSY
* then it's possible that the hardware has completed (or aborted) a transfer,
* so the driver needs to update that status.
static inline enum dma_channel_status
dma_channel_status(struct dma_channel *c)
return (is_dma_capable() && c) ? c->status : MUSB_DMA_STATUS_UNKNOWN;
* struct dma_controller - A DMA Controller.
* @musb: the usb controller
* @start: call this to start a DMA controller;
* return 0 on success, else negative errno
* @stop: call this to stop a DMA controller
* return 0 on success, else negative errno
* @channel_alloc: call this to allocate a DMA channel
* @channel_release: call this to release a DMA channel
* @channel_abort: call this to abort a pending DMA transaction,
* returning it to FREE (but allocated) state
* @dma_callback: invoked on DMA completion, useful to run platform
* code such IRQ acknowledgment.
* Controllers manage dma channels.
struct dma_controller {
struct musb *musb;
struct dma_channel *(*channel_alloc)(struct dma_controller *,
struct musb_hw_ep *, u8 is_tx);
void (*channel_release)(struct dma_channel *);
int (*channel_program)(struct dma_channel *channel,
u16 maxpacket, u8 mode,
dma_addr_t dma_addr,
u32 length);
int (*channel_abort)(struct dma_channel *);
int (*is_compatible)(struct dma_channel *channel,
u16 maxpacket,
void *buf, u32 length);
void (*dma_callback)(struct dma_controller *);
/* called after channel_program(), may indicate a fault */
extern void musb_dma_completion(struct musb *musb, u8 epnum, u8 transmit);
static inline struct dma_controller *
musb_dma_controller_create(struct musb *m, void __iomem *io)
return NULL;
static inline void musb_dma_controller_destroy(struct dma_controller *d) { }
extern struct dma_controller *
(*musb_dma_controller_create)(struct musb *, void __iomem *);
extern void (*musb_dma_controller_destroy)(struct dma_controller *);
/* Platform specific DMA functions */
extern struct dma_controller *
musbhs_dma_controller_create(struct musb *musb, void __iomem *base);
extern void musbhs_dma_controller_destroy(struct dma_controller *c);
extern struct dma_controller *
tusb_dma_controller_create(struct musb *musb, void __iomem *base);
extern void tusb_dma_controller_destroy(struct dma_controller *c);
extern struct dma_controller *
cppi_dma_controller_create(struct musb *musb, void __iomem *base);
extern void cppi_dma_controller_destroy(struct dma_controller *c);
extern struct dma_controller *
cppi41_dma_controller_create(struct musb *musb, void __iomem *base);
extern void cppi41_dma_controller_destroy(struct dma_controller *c);
extern struct dma_controller *
ux500_dma_controller_create(struct musb *musb, void __iomem *base);
extern void ux500_dma_controller_destroy(struct dma_controller *c);
#endif /* __MUSB_DMA_H__ */