/*
* include/asm-ppc/ppc4xx_dma.h
*
* IBM PPC4xx DMA engine library
*
* Copyright 2000-2004 MontaVista Software Inc.
*
* Cleaned up a bit more, Matt Porter <mporter@kernel.crashing.org>
*
* Original code by Armin Kuster <akuster@mvista.com>
* and Pete Popov <ppopov@mvista.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifdef __KERNEL__
#ifndef __ASMPPC_PPC4xx_DMA_H
#define __ASMPPC_PPC4xx_DMA_H
#include <linux/types.h>
#include <asm/mmu.h>
#include <asm/ibm4xx.h>
#undef DEBUG_4xxDMA
#define MAX_PPC4xx_DMA_CHANNELS 4
/*
* Function return status codes
* These values are used to indicate whether or not the function
* call was successful, or a bad/invalid parameter was passed.
*/
#define DMA_STATUS_GOOD 0
#define DMA_STATUS_BAD_CHANNEL 1
#define DMA_STATUS_BAD_HANDLE 2
#define DMA_STATUS_BAD_MODE 3
#define DMA_STATUS_NULL_POINTER 4
#define DMA_STATUS_OUT_OF_MEMORY 5
#define DMA_STATUS_SGL_LIST_EMPTY 6
#define DMA_STATUS_GENERAL_ERROR 7
#define DMA_STATUS_CHANNEL_NOTFREE 8
#define DMA_CHANNEL_BUSY 0x80000000
/*
* These indicate status as returned from the DMA Status Register.
*/
#define DMA_STATUS_NO_ERROR 0
#define DMA_STATUS_CS 1 /* Count Status */
#define DMA_STATUS_TS 2 /* Transfer Status */
#define DMA_STATUS_DMA_ERROR 3 /* DMA Error Occurred */
#define DMA_STATUS_DMA_BUSY 4 /* The channel is busy */
/*
* DMA Channel Control Registers
*/
#ifdef CONFIG_44x
#define PPC4xx_DMA_64BIT
#define DMA_CR_OFFSET 1
#else
#define DMA_CR_OFFSET 0
#endif
#define DMA_CE_ENABLE (1<<31) /* DMA Channel Enable */
#define SET_DMA_CE_ENABLE(x) (((x)&0x1)<<31)
#define GET_DMA_CE_ENABLE(x) (((x)&DMA_CE_ENABLE)>>31)
#define DMA_CIE_ENABLE (1<<30) /* DMA Channel Interrupt Enable */
#define SET_DMA_CIE_ENABLE(x) (((x)&0x1)<<30)
#define GET_DMA_CIE_ENABLE(x) (((x)&DMA_CIE_ENABLE)>>30)
#define DMA_TD (1<<29)
#define SET_DMA_TD(x) (((x)&0x1)<<29)
#define GET_DMA_TD(x) (((x)&DMA_TD)>>29)
#define DMA_PL (1<<28) /* Peripheral Location */
#define SET_DMA_PL(x) (((x)&0x1)<<28)
#define GET_DMA_PL(x) (((x)&DMA_PL)>>28)
#define EXTERNAL_PERIPHERAL 0
#define INTERNAL_PERIPHERAL 1
#define SET_DMA_PW(x) (((x)&0x3)<<(26-DMA_CR_OFFSET)) /* Peripheral Width */
#define DMA_PW_MASK SET_DMA_PW(3)
#define PW_8 0
#define PW_16 1
#define PW_32 2
#define PW_64 3
/* FIXME: Add PW_128 support for 440GP DMA block */
#define GET_DMA_PW(x) (((x)&DMA_PW_MASK)>>(26-DMA_CR_OFFSET))
#define DMA_DAI (1<<(25-DMA_CR_OFFSET)) /* Destination Address Increment */
#define SET_DMA_DAI(x) (((x)&0x1)<<(25-DMA_CR_OFFSET))
#define DMA_SAI (1<<(24-DMA_CR_OFFSET)) /* Source Address Increment */
#define SET_DMA_SAI(x) (((x)&0x1)<<(24-DMA_CR_OFFSET))
#define DMA_BEN (1<<(23-DMA_CR_OFFSET)) /* Buffer Enable */
#define SET_DMA_BEN(x) (((x)&0x1)<<(23-DMA_CR_OFFSET))
#define SET_DMA_TM(x) (((x)&0x3)<<(21-DMA_CR_OFFSET)) /* Transfer Mode */
#define DMA_TM_MASK SET_DMA_TM(3)
#define TM_PERIPHERAL 0 /* Peripheral */
#define TM_RESERVED 1 /* Reserved */
#define TM_S_MM 2 /* Memory to Memory */
#define TM_D_MM 3 /* Device Paced Memory to Memory */
#define GET_DMA_TM(x) (((x)&DMA_TM_MASK)>>(21-DMA_CR_OFFSET))
#define SET_DMA_PSC(x) (((x)&0x3)<<(19-DMA_CR_OFFSET)) /* Peripheral Setup Cycles */
#define DMA_PSC_MASK SET_DMA_PSC(3)
#define GET_DMA_PSC(x) (((x)&DMA_PSC_MASK)>>(19-DMA_CR_OFFSET))
#define SET_DMA_PWC(x) (((x)&0x3F)<<(13-DMA_CR_OFFSET)) /* Peripheral Wait Cycles */
#define DMA_PWC_MASK SET_DMA_PWC(0x3F)
#define GET_DMA_PWC(x) (((x)&DMA_PWC_MASK)>>(13-DMA_CR_OFFSET))
#define SET_DMA_PHC(x) (((x)&0x7)<<(10-DMA_CR_OFFSET)) /* Peripheral Hold Cycles */
#define DMA_PHC_MASK SET_DMA_PHC(0x7)
#define GET_DMA_PHC(x) (((x)&DMA_PHC_MASK)>>(10-DMA_CR_OFFSET))
#define DMA_ETD_OUTPUT (1<<(9-DMA_CR_OFFSET)) /* EOT pin is a TC output */
#define SET_DMA_ETD(x) (((x)&0x1)<<(9-DMA_CR_OFFSET))
#define DMA_TCE_ENABLE (1<<(8-DMA_CR_OFFSET))
#define SET_DMA_TCE(x) (((x)&0x1)<<(8-DMA_CR_OFFSET))
#define DMA_DEC (1<<(2)) /* Address Decrement */
#define SET_DMA_DEC(x) (((x)&0x1)<<2)
#define GET_DMA_DEC(x) (((x)&DMA_DEC)>>2)
/*
* Transfer Modes
* These modes are defined in a way that makes it possible to
* simply "or" in the value in the control register.
*/
#define DMA_MODE_MM (SET_DMA_TM(TM_S_MM)) /* memory to memory */
/* Device-paced memory to memory, */
/* device is at source address */
#define DMA_MODE_MM_DEVATSRC (DMA_TD | SET_DMA_TM(TM_D_MM))
/* Device-paced memory to memory, */
/* device is at destination address */
#define DMA_MODE_MM_DEVATDST (SET_DMA_TM(TM_D_MM))
/* 405gp/440gp */
#define SET_DMA_PREFETCH(x) (((x)&0x3)<<(4-DMA_CR_OFFSET)) /* Memory Read Prefetch */
#define DMA_PREFETCH_MASK SET_DMA_PREFETCH(3)
#define PREFETCH_1 0 /* Prefetch 1 Double Word */
#define PREFETCH_2 1
#define PREFETCH_4 2
#define GET_DMA_PREFETCH(x) (((x)&DMA_PREFETCH_MASK)>>(4-DMA_CR_OFFSET))
#define DMA_PCE (1<<(3-DMA_CR_OFFSET)) /* Parity Check Enable */
#define SET_DMA_PCE(x) (((x)&0x1)<<(3-DMA_CR_OFFSET))
#define GET_DMA_PCE(x) (((x)&DMA_PCE)>>(3-DMA_CR_OFFSET))
/* stb3x */
#define DMA_ECE_ENABLE (1<<5)
#define SET_DMA_ECE(x) (((x)&0x1)<<5)
#define GET_DMA_ECE(x) (((x)&DMA_ECE_ENABLE)>>5)
#define DMA_TCD_DISABLE (1<<4)
#define SET_DMA_TCD(x) (((x)&0x1)<<4)
#define GET_DMA_TCD(x) (((x)&DMA_TCD_DISABLE)>>4)
typedef uint32_t sgl_handle_t;
#ifdef CONFIG_PPC4xx_EDMA
#define SGL_LIST_SIZE 4096
#define DMA_PPC4xx_SIZE SGL_LIST_SIZE
#define SET_DMA_PRIORITY(x) (((x)&0x3)<<(6-DMA_CR_OFFSET)) /* DMA Channel Priority */
#define DMA_PRIORITY_MASK SET_DMA_PRIORITY(3)
#define PRIORITY_LOW 0
#define PRIORITY_MID_LOW 1
#define PRIORITY_MID_HIGH 2
#define PRIORITY_HIGH 3
#define GET_DMA_PRIORITY(x) (((x)&DMA_PRIORITY_MASK)>>(6-DMA_CR_OFFSET))
/*
* DMA Polarity Configuration Register
*/
#define DMAReq_ActiveLow(chan) (1<<(31-(chan*3)))
#define DMAAck_ActiveLow(chan) (1<<(30-(chan*3)))
#define EOT_ActiveLow(chan) (1<<(29-(chan*3))) /* End of Transfer */
/*
* DMA Sleep Mode Register
*/
#define SLEEP_MODE_ENABLE (1<<21)
/*
* DMA Status Register
*/
#define DMA_CS0 (1<<31) /* Terminal Count has been reached */
#define DMA_CS1 (1<<30)
#define DMA_CS2 (1<<29)
#define DMA_CS3 (1<<28)
#define DMA_TS0 (1<<27) /* End of Transfer has been requested */
#define DMA_TS1 (1<<26)
#define DMA_TS2 (1<<25)
#define DMA_TS3 (1<<24)
#define DMA_CH0_ERR (1<<23) /* DMA Chanel 0 Error */
#define DMA_CH1_ERR (1<<22)
#define DMA_CH2_ERR (1<<21)
#define DMA_CH3_ERR (1<<20)
#define DMA_IN_DMA_REQ0 (1<<19) /* Internal DMA Request is pending */
#define DMA_IN_DMA_REQ1 (1<<18)
#define DMA_IN_DMA_REQ2 (1<<17)
#define DMA_IN_DMA_REQ3 (1<<16)
#define DMA_EXT_DMA_REQ0 (1<<15) /* External DMA Request is pending */
#define DMA_EXT_DMA_REQ1 (1<<14)
#define DMA_EXT_DMA_REQ2 (1<<13)
#define DMA_EXT_DMA_REQ3 (1<<12)
#define DMA_CH0_BUSY (1<<11) /* DMA Channel 0 Busy */
#define DMA_CH1_BUSY (1<<10)
#define DMA_CH2_BUSY (1<<9)
#define DMA_CH3_BUSY (1<<8)
#define DMA_SG0 (1<<7) /* DMA Channel 0 Scatter/Gather in progress */
#define DMA_SG1 (1<<6)
#define DMA_SG2 (1<<5)
#define DMA_SG3 (1<<4)
/* DMA Channel Count Register */
#define DMA_CTC_BTEN (1<<23) /* Burst Enable/Disable bit */
#define DMA_CTC_BSIZ_MSK (3<<21) /* Mask of the Burst size bits */
#define DMA_CTC_BSIZ_2 (0)
#define DMA_CTC_BSIZ_4 (1<<21)
#define DMA_CTC_BSIZ_8 (2<<21)
#define DMA_CTC_BSIZ_16 (3<<21)
/*
* DMA SG Command Register
*/
#define SSG_ENABLE(chan) (1<<(31-chan)) /* Start Scatter Gather */
#define SSG_MASK_ENABLE(chan) (1<<(15-chan)) /* Enable writing to SSG0 bit */
/*
* DMA Scatter/Gather Descriptor Bit fields
*/
#define SG_LINK (1<<31) /* Link */
#define SG_TCI_ENABLE (1<<29) /* Enable Terminal Count Interrupt */
#define SG_ETI_ENABLE (1<<28) /* Enable End of Transfer Interrupt */
#define SG_ERI_ENABLE (1<<27) /* Enable Error Interrupt */
#define SG_COUNT_MASK 0xFFFF /* Count Field */
#define SET_DMA_CONTROL \
(SET_DMA_CIE_ENABLE(p_init->int_enable) | /* interrupt enable */ \
SET_DMA_BEN(p_init->buffer_enable) | /* buffer enable */\
SET_DMA_ETD(p_init->etd_output) | /* end of transfer pin */ \
SET_DMA_TCE(p_init->tce_enable) | /* terminal count enable */ \
SET_DMA_PL(p_init->pl) | /* peripheral location */ \
SET_DMA_DAI(p_init->dai) | /* dest addr increment */ \
SET_DMA_SAI(p_init->sai) | /* src addr increment */ \
SET_DMA_PRIORITY(p_init->cp) | /* channel priority */ \
SET_DMA_PW(p_init->pwidth) | /* peripheral/bus width */ \
SET_DMA_PSC(p_init->psc) | /* peripheral setup cycles */ \
SET_DMA_PWC(p_init->pwc) | /* peripheral wait cycles */ \
SET_DMA_PHC(p_init->phc) | /* peripheral hold cycles */ \
SET_DMA_PREFETCH(p_init->pf) /* read prefetch */)
#define GET_DMA_POLARITY(chan) (DMAReq_ActiveLow(chan) | DMAAck_ActiveLow(chan) | EOT_ActiveLow(chan))
#elif defined(CONFIG_STB03xxx) /* stb03xxx */
#define DMA_PPC4xx_SIZE 4096
/*
* DMA Status Register
*/
#define SET_DMA_PRIORITY(x) (((x)&0x00800001)) /* DMA Channel Priority */
#define DMA_PRIORITY_MASK 0x00800001
#define PRIORITY_LOW 0x00000000
#define PRIORITY_MID_LOW 0x00000001
#define PRIORITY_MID_HIGH 0x00800000
#define PRIORITY_HIGH 0x00800001
#define GET_DMA_PRIORITY(x) (((((x)&DMA_PRIORITY_MASK) &0x00800000) >> 22 ) | (((x)&DMA_PRIORITY_MASK) &0x00000001))
#define DMA_CS0 (1<<31) /* Terminal Count has been reached */
#define DMA_CS1 (1<<30)
#define DMA_CS2 (1<<29)
#define DMA_CS3 (1<<28)
#define DMA_TS0 (1<<27) /* End of Transfer has been requested */
#define DMA_TS1 (1<<26)
#define DMA_TS2 (1<<25)
#define DMA_TS3 (1<<24)
#define DMA_CH0_ERR (1<<23) /* DMA Chanel 0 Error */
#define DMA_CH1_ERR (1<<22)
#define DMA_CH2_ERR (1<<21)
#define DMA_CH3_ERR (1<<20)
#define DMA_CT0 (1<<19) /* Chained transfere */
#define DMA_IN_DMA_REQ0 (1<<18) /* Internal DMA Request is pending */
#define DMA_IN_DMA_REQ1 (1<<17)
#define DMA_IN_DMA_REQ2 (1<<16)
#define DMA_IN_DMA_REQ3 (1<<15)
#define DMA_EXT_DMA_REQ0 (1<<14) /* External DMA Request is pending */
#define DMA_EXT_DMA_REQ1 (1<<13)
#define DMA_EXT_DMA_REQ2 (1<<12)
#define DMA_EXT_DMA_REQ3 (1<<11)
#define DMA_CH0_BUSY (1<<10) /* DMA Channel 0 Busy */
#define DMA_CH1_BUSY (1<<9)
#define DMA_CH2_BUSY (1<<8)
#define DMA_CH3_BUSY (1<<7)
#define DMA_CT1 (1<<6) /* Chained transfere */
#define DMA_CT2 (1<<5)
#define DMA_CT3 (1<<4)
#define DMA_CH_ENABLE (1<<7)
#define SET_DMA_CH(x) (((x)&0x1)<<7)
#define GET_DMA_CH(x) (((x)&DMA_CH_ENABLE)>>7)
/* STBx25xxx dma unique */
/* enable device port on a dma channel
* example ext 0 on dma 1
*/
#define SSP0_RECV 15
#define SSP0_XMIT 14
#define EXT_DMA_0 12
#define SC1_XMIT 11
#define SC1_RECV 10
#define EXT_DMA_2 9
#define EXT_DMA_3 8
#define SERIAL2_XMIT 7
#define SERIAL2_RECV 6
#define SC0_XMIT 5
#define SC0_RECV 4
#define SERIAL1_XMIT 3
#define SERIAL1_RECV 2
#define SERIAL0_XMIT 1
#define SERIAL0_RECV 0
#define DMA_CHAN_0 1
#define DMA_CHAN_1 2
#define DMA_CHAN_2 3
#define DMA_CHAN_3 4
/* end STBx25xx */
/*
* Bit 30 must be one for Redwoods, otherwise transfers may receive errors.
*/
#define DMA_CR_MB0 0x2
#define SET_DMA_CONTROL \
(SET_DMA_CIE_ENABLE(p_init->int_enable) | /* interrupt enable */ \
SET_DMA_ETD(p_init->etd_output) | /* end of transfer pin */ \
SET_DMA_TCE(p_init->tce_enable) | /* terminal count enable */ \
SET_DMA_PL(p_init->pl) | /* peripheral location */ \
SET_DMA_DAI(p_init->dai) | /* dest addr increment */ \
SET_DMA_SAI(p_init->sai) | /* src addr increment */ \
SET_DMA_PRIORITY(p_init->cp) | /* channel priority */ \
SET_DMA_PW(p_init->pwidth) | /* peripheral/bus width */ \
SET_DMA_PSC(p_init->psc) | /* peripheral setup cycles */ \
SET_DMA_PWC(p_init->pwc) | /* peripheral wait cycles */ \
SET_DMA_PHC(p_init->phc) | /* peripheral hold cycles */ \
SET_DMA_TCD(p_init->tcd_disable) | /* TC chain mode disable */ \
SET_DMA_ECE(p_init->ece_enable) | /* ECE chanin mode enable */ \
SET_DMA_CH(p_init->ch_enable) | /* Chain enable */ \
DMA_CR_MB0 /* must be one */)
#define GET_DMA_POLARITY(chan) chan
#endif
typedef struct {
unsigned short in_use; /* set when channel is being used, clr when
* available.
*/
/*
* Valid polarity settings:
* DMAReq_ActiveLow(n)
* DMAAck_ActiveLow(n)
* EOT_ActiveLow(n)
*
* n is 0 to max dma chans
*/
unsigned int polarity;
char buffer_enable; /* Boolean: buffer enable */
char tce_enable; /* Boolean: terminal count enable */
char etd_output; /* Boolean: eot pin is a tc output */
char pce; /* Boolean: parity check enable */
/*
* Peripheral location:
* INTERNAL_PERIPHERAL (UART0 on the 405GP)
* EXTERNAL_PERIPHERAL
*/
char pl; /* internal/external peripheral */
/*
* Valid pwidth settings:
* PW_8
* PW_16
* PW_32
* PW_64
*/
unsigned int pwidth;
char dai; /* Boolean: dst address increment */
char sai; /* Boolean: src address increment */
/*
* Valid psc settings: 0-3
*/
unsigned int psc; /* Peripheral Setup Cycles */
/*
* Valid pwc settings:
* 0-63
*/
unsigned int pwc; /* Peripheral Wait Cycles */
/*
* Valid phc settings:
* 0-7
*/
unsigned int phc; /* Peripheral Hold Cycles */
/*
* Valid cp (channel priority) settings:
* PRIORITY_LOW
* PRIORITY_MID_LOW
* PRIORITY_MID_HIGH
* PRIORITY_HIGH
*/
unsigned int cp; /* channel priority */
/*
* Valid pf (memory read prefetch) settings:
*
* PREFETCH_1
* PREFETCH_2
* PREFETCH_4
*/
unsigned int pf; /* memory read prefetch */
/*
* Boolean: channel interrupt enable
* NOTE: for sgl transfers, only the last descriptor will be setup to
* interrupt.
*/
char int_enable;
char shift; /* easy access to byte_count shift, based on */
/* the width of the channel */
uint32_t control; /* channel control word */
/* These variabled are used ONLY in single dma transfers */
unsigned int mode; /* transfer mode */
phys_addr_t addr;
char ce; /* channel enable */
#ifdef CONFIG_STB03xxx
char ch_enable;
char tcd_disable;
char ece_enable;
char td; /* transfer direction */
#endif
char int_on_final_sg;/* for scatter/gather - only interrupt on last sg */
} ppc_dma_ch_t;
/*
* PPC44x DMA implementations have a slightly different
* descriptor layout. Probably moved about due to the
* change to 64-bit addresses and link pointer. I don't
* know why they didn't just leave control_count after
* the dst_addr.
*/
#ifdef PPC4xx_DMA_64BIT
typedef struct {
uint32_t control;
uint32_t control_count;
phys_addr_t src_addr;
phys_addr_t dst_addr;
phys_addr_t next;
} ppc_sgl_t;
#else
typedef struct {
uint32_t control;
phys_addr_t src_addr;
phys_addr_t dst_addr;
uint32_t control_count;
uint32_t next;
} ppc_sgl_t;
#endif
typedef struct {
unsigned int dmanr;
uint32_t control; /* channel ctrl word; loaded from each descrptr */
uint32_t sgl_control; /* LK, TCI, ETI, and ERI bits in sgl descriptor */
dma_addr_t dma_addr; /* dma (physical) address of this list */
ppc_sgl_t *phead;
dma_addr_t phead_dma;
ppc_sgl_t *ptail;
dma_addr_t ptail_dma;
} sgl_list_info_t;
typedef struct {
phys_addr_t *src_addr;
phys_addr_t *dst_addr;
phys_addr_t dma_src_addr;
phys_addr_t dma_dst_addr;
} pci_alloc_desc_t;
extern ppc_dma_ch_t dma_channels[];
/*
* The DMA API are in ppc4xx_dma.c and ppc4xx_sgdma.c
*/
extern int ppc4xx_init_dma_channel(unsigned int, ppc_dma_ch_t *);
extern int ppc4xx_get_channel_config(unsigned int, ppc_dma_ch_t *);
extern int ppc4xx_set_channel_priority(unsigned int, unsigned int);
extern unsigned int ppc4xx_get_peripheral_width(unsigned int);
extern void ppc4xx_set_sg_addr(int, phys_addr_t);
extern int ppc4xx_add_dma_sgl(sgl_handle_t, phys_addr_t, phys_addr_t, unsigned int);
extern void ppc4xx_enable_dma_sgl(sgl_handle_t);
extern void ppc4xx_disable_dma_sgl(sgl_handle_t);
extern int ppc4xx_get_dma_sgl_residue(sgl_handle_t, phys_addr_t *, phys_addr_t *);
extern int ppc4xx_delete_dma_sgl_element(sgl_handle_t, phys_addr_t *, phys_addr_t *);
extern int ppc4xx_alloc_dma_handle(sgl_handle_t *, unsigned int, unsigned int);
extern void ppc4xx_free_dma_handle(sgl_handle_t);
extern int ppc4xx_get_dma_status(void);
extern int ppc4xx_enable_burst(unsigned int);
extern int ppc4xx_disable_burst(unsigned int);
extern int ppc4xx_set_burst_size(unsigned int, unsigned int);
extern void ppc4xx_set_src_addr(int dmanr, phys_addr_t src_addr);
extern void ppc4xx_set_dst_addr(int dmanr, phys_addr_t dst_addr);
extern void ppc4xx_enable_dma(unsigned int dmanr);
extern void ppc4xx_disable_dma(unsigned int dmanr);
extern void ppc4xx_set_dma_count(unsigned int dmanr, unsigned int count);
extern int ppc4xx_get_dma_residue(unsigned int dmanr);
extern void ppc4xx_set_dma_addr2(unsigned int dmanr, phys_addr_t src_dma_addr,
phys_addr_t dst_dma_addr);
extern int ppc4xx_enable_dma_interrupt(unsigned int dmanr);
extern int ppc4xx_disable_dma_interrupt(unsigned int dmanr);
extern int ppc4xx_clr_dma_status(unsigned int dmanr);
extern int ppc4xx_map_dma_port(unsigned int dmanr, unsigned int ocp_dma,short dma_chan);
extern int ppc4xx_disable_dma_port(unsigned int dmanr, unsigned int ocp_dma,short dma_chan);
extern int ppc4xx_set_dma_mode(unsigned int dmanr, unsigned int mode);
/* These are in kernel/dma.c: */
/* reserve a DMA channel */
extern int request_dma(unsigned int dmanr, const char *device_id);
/* release it again */
extern void free_dma(unsigned int dmanr);
#endif
#endif /* __KERNEL__ */
