/* *  linux/arch/arm/mach-sa1100/dma-sa1111.c * *  Copyright (C) 2000 John Dorsey * *  This program is free software; you can redistribute it and/or modify *  it under the terms of the GNU General Public License version 2 as *  published by the Free Software Foundation. * *  4 September 2000 - created. */#include <linux/module.h>#include <linux/init.h>#include <linux/sched.h>#include <linux/delay.h>#include <linux/spinlock.h>#include <linux/errno.h>#include <asm/system.h>#include <asm/irq.h>#include <asm/hardware.h>#include <asm/io.h>#include <asm/dma.h>#include <asm/hardware/sa1111.h>// #define DEBUG#ifdef DEBUG#define DPRINTK( s, arg... )  printk( "dma<%s>: " s, dma->device_id , ##arg )#else#define DPRINTK( x... )#endif/* * Control register structure for the SA1111 SAC DMA */typedef struct {	volatile u_long SAD_CS;	volatile dma_addr_t SAD_SA;	volatile u_long SAD_CA;	volatile dma_addr_t SAD_SB;	volatile u_long SAD_CB;} dma_regs_t;#include "dma.h"void sa1111_reset_sac_dma(dmach_t channel){	sa1100_dma_t *dma = &dma_chan[channel];	dma->regs->SAD_CS = 0;	mdelay(1);	dma->dma_a = dma->dma_b = 0;}int start_sa1111_sac_dma(sa1100_dma_t *dma, dma_addr_t dma_ptr, size_t size){  	dma_regs_t *sac_regs = dma->regs;	DPRINTK(" SAC DMA %cCS %02x at %08x (%d)\n",		(sac_regs==&SADTCS)?'T':'R', sac_regs->SAD_CS, dma_ptr, size);	/* The minimum transfer length requirement has not yet been	 * verified:	 */	if( size < SA1111_SAC_DMA_MIN_XFER )	  printk(KERN_WARNING "Warning: SAC xfers below %u bytes may be buggy!"		 " (%u bytes)\n", SA1111_SAC_DMA_MIN_XFER, size);	if( dma->dma_a && dma->dma_b ){	  	DPRINTK("  neither engine available! (A %d, B %d)\n",			dma->dma_a, dma->dma_b);	  	return -1;	}	if( sa1111_check_dma_bug(dma_ptr) )	  	printk(KERN_WARNING "Warning: DMA address %08x is buggy!\n",		       dma_ptr);	if( (dma->last_dma || dma->dma_b) && dma->dma_a == 0 ){	  	if( sac_regs->SAD_CS & SAD_CS_DBDB ){		  	DPRINTK("  awaiting \"done B\" interrupt, not starting\n");			return -1;		}		sac_regs->SAD_SA = SA1111_DMA_ADDR((u_int)dma_ptr);		sac_regs->SAD_CA = size;		sac_regs->SAD_CS = SAD_CS_DSTA | SAD_CS_DEN;		++dma->dma_a;		DPRINTK("  with A [%02lx %08lx %04lx]\n", sac_regs->SAD_CS,			sac_regs->SAD_SA, sac_regs->SAD_CA);	} else {	  	if( sac_regs->SAD_CS & SAD_CS_DBDA ){		  	DPRINTK("  awaiting \"done A\" interrupt, not starting\n");			return -1;		}		sac_regs->SAD_SB = SA1111_DMA_ADDR((u_int)dma_ptr);		sac_regs->SAD_CB = size;		sac_regs->SAD_CS = SAD_CS_DSTB | SAD_CS_DEN;		++dma->dma_b;		DPRINTK("  with B [%02lx %08lx %04lx]\n", sac_regs->SAD_CS,			sac_regs->SAD_SB, sac_regs->SAD_CB);	}	/* Additional delay to avoid DMA engine lockup during record: */	if( sac_regs == (dma_regs_t*)&SADRCS )	  	mdelay(1);	/* NP : wouuuh! ugly... */	return 0;}static void sa1111_sac_dma_irq(int irq, void *dev_id, struct pt_regs *regs){  	sa1100_dma_t *dma = (sa1100_dma_t *) dev_id;	DPRINTK("irq %d, last DMA serviced was %c, CS %02x\n", irq,		dma->last_dma?'B':'A', dma->regs->SAD_CS);	/* Occasionally, one of the DMA engines (A or B) will	 * lock up. We try to deal with this by quietly kicking	 * the control register for the afflicted transfer	 * direction.	 *	 * Note for the debugging-inclined: we currently aren't	 * properly flushing the DMA engines during channel	 * shutdown. A slight hiccup at the beginning of playback	 * after a channel has been stopped can be heard as	 * evidence of this. Programmatically, this shows up	 * as either a locked engine, or a spurious interrupt. -jd	 */	if(irq==AUDXMTDMADONEA || irq==AUDRCVDMADONEA){	  	if(dma->last_dma == 0){		  	DPRINTK("DMA B has locked up!\n");			dma->regs->SAD_CS = 0;			mdelay(1);			dma->dma_a = dma->dma_b = 0;		} else {		  	if(dma->dma_a == 0)			  	DPRINTK("spurious SAC IRQ %d\n", irq);			else {			  	--dma->dma_a;				/* Servicing the SAC DMA engines too quickly				 * after they issue a DONE interrupt causes				 * them to lock up.				 */				if(irq==AUDRCVDMADONEA || irq==AUDRCVDMADONEB)				  	mdelay(1);			}		}		dma->regs->SAD_CS = SAD_CS_DBDA | SAD_CS_DEN; /* w1c */		dma->last_dma = 0;	} else {	  	if(dma->last_dma == 1){		  	DPRINTK("DMA A has locked up!\n");			dma->regs->SAD_CS = 0;			mdelay(1);			dma->dma_a = dma->dma_b = 0;		} else {		  	if(dma->dma_b == 0)			  	DPRINTK("spurious SAC IRQ %d\n", irq);			else {			  	--dma->dma_b;				/* See lock-up note above. */				if(irq==AUDRCVDMADONEA || irq==AUDRCVDMADONEB)				  	mdelay(1);			}		}		dma->regs->SAD_CS = SAD_CS_DBDB | SAD_CS_DEN; /* w1c */		dma->last_dma = 1;	}	/* NP: maybe this shouldn't be called in all cases? */	sa1100_dma_done (dma);}int sa1111_sac_request_dma(dmach_t *channel, const char *device_id,			   unsigned int direction){	sa1100_dma_t *dma = NULL;	int ch, irq, err;	*channel = -1;		/* to be sure we catch the freeing of a misregistered channel */	ch = SA1111_SAC_DMA_BASE + direction;	if (!channel_is_sa1111_sac(ch)) {	  	printk(KERN_ERR "%s: invalid SA-1111 SAC DMA channel (%d)\n",		       device_id, ch);		return -1;	}	dma = &dma_chan[ch];	if (xchg(&dma->in_use, 1) == 1) {	  	printk(KERN_ERR "%s: SA-1111 SAC DMA channel %d in use\n",		       device_id, ch);		return -EBUSY;	}	irq = AUDXMTDMADONEA + direction;	err = request_irq(irq, sa1111_sac_dma_irq, SA_INTERRUPT,			  device_id, (void *) dma);	if (err) {		printk(KERN_ERR		       "%s: unable to request IRQ %d for DMA channel %d (A)\n",		       device_id, irq, ch);		dma->in_use = 0;		return err;	}	irq = AUDXMTDMADONEB + direction;	err = request_irq(irq, sa1111_sac_dma_irq, SA_INTERRUPT,			  device_id, (void *) dma);	if (err) {		printk(KERN_ERR		       "%s: unable to request IRQ %d for DMA channel %d (B)\n",		       device_id, irq, ch);		dma->in_use = 0;		return err;	}	*channel = ch;	dma->device_id = device_id;	dma->callback = NULL;	dma->spin_size = 0;	return 0;}/* FIXME:  need to complete the three following functions */int sa1111_dma_get_current(dmach_t channel, void **buf_id, dma_addr_t *addr){	sa1100_dma_t *dma = &dma_chan[channel];	int flags, ret;	local_irq_save(flags);	if (dma->curr && dma->spin_ref <= 0) {		dma_buf_t *buf = dma->curr;		if (buf_id)			*buf_id = buf->id;		/* not fully accurate but still... */		*addr = buf->dma_ptr;		ret = 0;	} else {		if (buf_id)			*buf_id = NULL;		*addr = 0;		ret = -ENXIO;	}	local_irq_restore(flags);	return ret;}int sa1111_dma_stop(dmach_t channel){	return 0;}int sa1111_dma_resume(dmach_t channel){	return 0;}void sa1111_cleanup_sac_dma(dmach_t channel){	sa1100_dma_t *dma = &dma_chan[channel];	free_irq(AUDXMTDMADONEA + (channel - SA1111_SAC_DMA_BASE), (void*) dma);	free_irq(AUDXMTDMADONEB + (channel - SA1111_SAC_DMA_BASE), (void*) dma);}/* According to the "Intel StrongARM SA-1111 Microprocessor Companion * Chip Specification Update" (June 2000), erratum #7, there is a * significant bug in Serial Audio Controller DMA. If the SAC is * accessing a region of memory above 1MB relative to the bank base, * it is important that address bit 10 _NOT_ be asserted. Depending * on the configuration of the RAM, bit 10 may correspond to one * of several different (processor-relative) address bits. * * This routine only identifies whether or not a given DMA address * is susceptible to the bug. */int sa1111_check_dma_bug(dma_addr_t addr){	unsigned int physaddr=SA1111_DMA_ADDR((unsigned int)addr);	/* Section 4.6 of the "Intel StrongARM SA-1111 Development Module	 * User's Guide" mentions that jumpers R51 and R52 control the	 * target of SA-1111 DMA (either SDRAM bank 0 on Assabet, or	 * SDRAM bank 1 on Neponset). The default configuration selects	 * Assabet, so any address in bank 1 is necessarily invalid.	 */	if((machine_is_assabet() || machine_is_pfs168()) && addr >= 0xc8000000)	  	return -1;	/* The bug only applies to buffers located more than one megabyte	 * above the start of the target bank:	 */	if(physaddr<(1<<20))	  	return 0;	switch(FExtr(SBI_SMCR, SMCR_DRAC)){	case 01: /* 10 row + bank address bits, A<20> must not be set */	  	if(physaddr & (1<<20))		  	return -1;		break;	case 02: /* 11 row + bank address bits, A<23> must not be set */	  	if(physaddr & (1<<23))		  	return -1;		break;	case 03: /* 12 row + bank address bits, A<24> must not be set */	  	if(physaddr & (1<<24))		  	return -1;		break;	case 04: /* 13 row + bank address bits, A<25> must not be set */	  	if(physaddr & (1<<25))		  	return -1;		break;	case 05: /* 14 row + bank address bits, A<20> must not be set */	  	if(physaddr & (1<<20))		  	return -1;		break;	case 06: /* 15 row + bank address bits, A<20> must not be set */	  	if(physaddr & (1<<20))		  	return -1;		break;	default:	  	printk(KERN_ERR "%s(): invalid SMCR DRAC value 0%lo\n",		       __FUNCTION__, FExtr(SBI_SMCR, SMCR_DRAC));		return -1;	}	return 0;}EXPORT_SYMBOL(sa1111_sac_request_dma);EXPORT_SYMBOL(sa1111_check_dma_bug);static int __init sa1111_init_sac_dma(void){	int channel = SA1111_SAC_DMA_BASE;	dma_chan[channel++].regs = (dma_regs_t *) &SADTCS;	dma_chan[channel++].regs = (dma_regs_t *) &SADRCS;	return 0;}__initcall(sa1111_init_sac_dma);