dma.c

linux 内核源代码

/*
 *  linux/arch/arm/mach-pnx4008/dma.c
 *
 *  PNX4008 DMA registration and IRQ dispatching
 *
 *  Author:	Vitaly Wool
 *  Copyright:	MontaVista Software Inc. (c) 2005
 *
 *  Based on the code from Nicolas Pitre
 *
 *  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.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/dma-mapping.h>
#include <linux/clk.h>

#include <asm/system.h>
#include <asm/hardware.h>
#include <asm/dma.h>
#include <asm/dma-mapping.h>
#include <asm/io.h>
#include <asm/mach/dma.h>
#include <asm/arch/clock.h>

static struct dma_channel {
	char *name;
	void (*irq_handler) (int, int, void *);
	void *data;
	struct pnx4008_dma_ll *ll;
	u32 ll_dma;
	void *target_addr;
	int target_id;
} dma_channels[MAX_DMA_CHANNELS];

static struct ll_pool {
	void *vaddr;
	void *cur;
	dma_addr_t dma_addr;
	int count;
} ll_pool;

static DEFINE_SPINLOCK(ll_lock);

struct pnx4008_dma_ll *pnx4008_alloc_ll_entry(dma_addr_t * ll_dma)
{
	struct pnx4008_dma_ll *ll = NULL;
	unsigned long flags;

	spin_lock_irqsave(&ll_lock, flags);
	if (ll_pool.count > 4) { /* can give one more */
		ll = *(struct pnx4008_dma_ll **) ll_pool.cur;
		*ll_dma = ll_pool.dma_addr + ((void *)ll - ll_pool.vaddr);
		*(void **)ll_pool.cur = **(void ***)ll_pool.cur;
		memset(ll, 0, sizeof(*ll));
		ll_pool.count--;
	}
	spin_unlock_irqrestore(&ll_lock, flags);

	return ll;
}

EXPORT_SYMBOL_GPL(pnx4008_alloc_ll_entry);

void pnx4008_free_ll_entry(struct pnx4008_dma_ll * ll, dma_addr_t ll_dma)
{
	unsigned long flags;

	if (ll) {
		if ((unsigned long)((long)ll - (long)ll_pool.vaddr) > 0x4000) {
			printk(KERN_ERR "Trying to free entry not allocated by DMA\n");
			BUG();
		}

		if (ll->flags & DMA_BUFFER_ALLOCATED)
			ll->free(ll->alloc_data);

		spin_lock_irqsave(&ll_lock, flags);
		*(long *)ll = *(long *)ll_pool.cur;
		*(long *)ll_pool.cur = (long)ll;
		ll_pool.count++;
		spin_unlock_irqrestore(&ll_lock, flags);
	}
}

EXPORT_SYMBOL_GPL(pnx4008_free_ll_entry);

void pnx4008_free_ll(u32 ll_dma, struct pnx4008_dma_ll * ll)
{
	struct pnx4008_dma_ll *ptr;
	u32 dma;

	while (ll) {
		dma = ll->next_dma;
		ptr = ll->next;
		pnx4008_free_ll_entry(ll, ll_dma);

		ll_dma = dma;
		ll = ptr;
	}
}

EXPORT_SYMBOL_GPL(pnx4008_free_ll);

static int dma_channels_requested = 0;

static inline void dma_increment_usage(void)
{
	if (!dma_channels_requested++) {
		struct clk *clk = clk_get(0, "dma_ck");
		if (!IS_ERR(clk)) {
			clk_set_rate(clk, 1);
			clk_put(clk);
		}
		pnx4008_config_dma(-1, -1, 1);
	}
}
static inline void dma_decrement_usage(void)
{
	if (!--dma_channels_requested) {
		struct clk *clk = clk_get(0, "dma_ck");
		if (!IS_ERR(clk)) {
			clk_set_rate(clk, 0);
			clk_put(clk);
		}
		pnx4008_config_dma(-1, -1, 0);

	}
}

static DEFINE_SPINLOCK(dma_lock);

static inline void pnx4008_dma_lock(void)
{
	spin_lock_irq(&dma_lock);
}

static inline void pnx4008_dma_unlock(void)
{
	spin_unlock_irq(&dma_lock);
}

#define VALID_CHANNEL(c)	(((c) >= 0) && ((c) < MAX_DMA_CHANNELS))

int pnx4008_request_channel(char *name, int ch,
			    void (*irq_handler) (int, int, void *), void *data)
{
	int i, found = 0;

	/* basic sanity checks */
	if (!name || (ch != -1 && !VALID_CHANNEL(ch)))
		return -EINVAL;

	pnx4008_dma_lock();

	/* try grabbing a DMA channel with the requested priority */
	for (i = MAX_DMA_CHANNELS - 1; i >= 0; i--) {
		if (!dma_channels[i].name && (ch == -1 || ch == i)) {
			found = 1;
			break;
		}
	}

	if (found) {
		dma_increment_usage();
		dma_channels[i].name = name;
		dma_channels[i].irq_handler = irq_handler;
		dma_channels[i].data = data;
		dma_channels[i].ll = NULL;
		dma_channels[i].ll_dma = 0;
	} else {
		printk(KERN_WARNING "No more available DMA channels for %s\n",
		       name);
		i = -ENODEV;
	}

	pnx4008_dma_unlock();
	return i;
}

EXPORT_SYMBOL_GPL(pnx4008_request_channel);

void pnx4008_free_channel(int ch)
{
	if (!dma_channels[ch].name) {
		printk(KERN_CRIT
		       "%s: trying to free channel %d which is already freed\n",
		       __FUNCTION__, ch);
		return;
	}

	pnx4008_dma_lock();
	pnx4008_free_ll(dma_channels[ch].ll_dma, dma_channels[ch].ll);
	dma_channels[ch].ll = NULL;
	dma_decrement_usage();

	dma_channels[ch].name = NULL;
	pnx4008_dma_unlock();
}

EXPORT_SYMBOL_GPL(pnx4008_free_channel);

int pnx4008_config_dma(int ahb_m1_be, int ahb_m2_be, int enable)
{
	unsigned long dma_cfg = __raw_readl(DMAC_CONFIG);

	switch (ahb_m1_be) {
	case 0:
		dma_cfg &= ~(1 << 1);
		break;
	case 1:
		dma_cfg |= (1 << 1);
		break;
	default:
		break;
	}

	switch (ahb_m2_be) {
	case 0:
		dma_cfg &= ~(1 << 2);
		break;
	case 1:
		dma_cfg |= (1 << 2);
		break;
	default:
		break;
	}

	switch (enable) {
	case 0:
		dma_cfg &= ~(1 << 0);
		break;
	case 1:
		dma_cfg |= (1 << 0);
		break;
	default:
		break;
	}

	pnx4008_dma_lock();
	__raw_writel(dma_cfg, DMAC_CONFIG);
	pnx4008_dma_unlock();

	return 0;
}

EXPORT_SYMBOL_GPL(pnx4008_config_dma);

int pnx4008_dma_pack_control(const struct pnx4008_dma_ch_ctrl * ch_ctrl,
			     unsigned long *ctrl)
{
	int i = 0, dbsize, sbsize, err = 0;

	if (!ctrl || !ch_ctrl) {
		err = -EINVAL;
		goto out;
	}

	*ctrl = 0;

	switch (ch_ctrl->tc_mask) {
	case 0:
		break;
	case 1:
		*ctrl |= (1 << 31);
		break;

	default:
		err = -EINVAL;
		goto out;
	}

	switch (ch_ctrl->cacheable) {
	case 0:
		break;
	case 1:
		*ctrl |= (1 << 30);
		break;

	default:
		err = -EINVAL;
		goto out;
	}
	switch (ch_ctrl->bufferable) {
	case 0:
		break;
	case 1:
		*ctrl |= (1 << 29);
		break;

	default:
		err = -EINVAL;
		goto out;
	}
	switch (ch_ctrl->priv_mode) {
	case 0:
		break;
	case 1:
		*ctrl |= (1 << 28);
		break;

	default:
		err = -EINVAL;
		goto out;
	}
	switch (ch_ctrl->di) {
	case 0:
		break;
	case 1:
		*ctrl |= (1 << 27);
		break;

	default:
		err = -EINVAL;
		goto out;
	}
	switch (ch_ctrl->si) {
	case 0:
		break;
	case 1:
		*ctrl |= (1 << 26);
		break;

	default:
		err = -EINVAL;
		goto out;
	}
	switch (ch_ctrl->dest_ahb1) {
	case 0:
		break;
	case 1:
		*ctrl |= (1 << 25);
		break;

	default:
		err = -EINVAL;
		goto out;
	}
	switch (ch_ctrl->src_ahb1) {
	case 0:
		break;
	case 1:
		*ctrl |= (1 << 24);
		break;

	default:
		err = -EINVAL;
		goto out;
	}
	switch (ch_ctrl->dwidth) {
	case WIDTH_BYTE:
		*ctrl &= ~(7 << 21);
		break;
	case WIDTH_HWORD:
		*ctrl &= ~(7 << 21);
		*ctrl |= (1 << 21);
		break;
	case WIDTH_WORD:
		*ctrl &= ~(7 << 21);
		*ctrl |= (2 << 21);
		break;

	default:
		err = -EINVAL;
		goto out;
	}
	switch (ch_ctrl->swidth) {
	case WIDTH_BYTE:
		*ctrl &= ~(7 << 18);
		break;
	case WIDTH_HWORD:
		*ctrl &= ~(7 << 18);
		*ctrl |= (1 << 18);
		break;
	case WIDTH_WORD:
		*ctrl &= ~(7 << 18);
		*ctrl |= (2 << 18);
		break;

	default:
		err = -EINVAL;
		goto out;
	}
	dbsize = ch_ctrl->dbsize;
	while (!(dbsize & 1)) {
		i++;
		dbsize >>= 1;
	}
	if (ch_ctrl->dbsize != 1 || i > 8 || i == 1) {
		err = -EINVAL;
		goto out;
	} else if (i > 1)
		i--;
	*ctrl &= ~(7 << 15);
	*ctrl |= (i << 15);

	sbsize = ch_ctrl->sbsize;
	while (!(sbsize & 1)) {
		i++;
		sbsize >>= 1;
	}
	if (ch_ctrl->sbsize != 1 || i > 8 || i == 1) {
		err = -EINVAL;
		goto out;
	} else if (i > 1)
		i--;
	*ctrl &= ~(7 << 12);
	*ctrl |= (i << 12);

	if (ch_ctrl->tr_size > 0x7ff) {
		err = -E2BIG;
		goto out;
	}
	*ctrl &= ~0x7ff;
	*ctrl |= ch_ctrl->tr_size & 0x7ff;

out:
	return err;
}

EXPORT_SYMBOL_GPL(pnx4008_dma_pack_control);

int pnx4008_dma_parse_control(unsigned long ctrl,
			      struct pnx4008_dma_ch_ctrl * ch_ctrl)
{
	int err = 0;

	if (!ch_ctrl) {
		err = -EINVAL;
		goto out;
	}

	ch_ctrl->tr_size = ctrl & 0x7ff;
	ctrl >>= 12;

	ch_ctrl->sbsize = 1 << (ctrl & 7);
	if (ch_ctrl->sbsize > 1)
		ch_ctrl->sbsize <<= 1;
	ctrl >>= 3;

	ch_ctrl->dbsize = 1 << (ctrl & 7);
	if (ch_ctrl->dbsize > 1)
		ch_ctrl->dbsize <<= 1;
	ctrl >>= 3;

	switch (ctrl & 7) {
	case 0:
		ch_ctrl->swidth = WIDTH_BYTE;
		break;
	case 1:
		ch_ctrl->swidth = WIDTH_HWORD;
		break;
	case 2:
		ch_ctrl->swidth = WIDTH_WORD;
		break;
	default:
		err = -EINVAL;
		goto out;
	}
	ctrl >>= 3;

	switch (ctrl & 7) {
	case 0:
		ch_ctrl->dwidth = WIDTH_BYTE;
		break;
	case 1:
		ch_ctrl->dwidth = WIDTH_HWORD;
		break;
	case 2:
		ch_ctrl->dwidth = WIDTH_WORD;
		break;
	default:
		err = -EINVAL;
		goto out;
	}
	ctrl >>= 3;

	ch_ctrl->src_ahb1 = ctrl & 1;
	ctrl >>= 1;

	ch_ctrl->dest_ahb1 = ctrl & 1;
	ctrl >>= 1;

	ch_ctrl->si = ctrl & 1;
	ctrl >>= 1;

	ch_ctrl->di = ctrl & 1;
	ctrl >>= 1;

	ch_ctrl->priv_mode = ctrl & 1;
	ctrl >>= 1;

	ch_ctrl->bufferable = ctrl & 1;
	ctrl >>= 1;

	ch_ctrl->cacheable = ctrl & 1;
	ctrl >>= 1;

	ch_ctrl->tc_mask = ctrl & 1;

out:
	return err;
}

EXPORT_SYMBOL_GPL(pnx4008_dma_parse_control);

int pnx4008_dma_pack_config(const struct pnx4008_dma_ch_config * ch_cfg,
			    unsigned long *cfg)
{
	int err = 0;

	if (!cfg || !ch_cfg) {
		err = -EINVAL;
		goto out;
	}

	*cfg = 0;

	switch (ch_cfg->halt) {
	case 0:
		break;
	case 1:
		*cfg |= (1 << 18);
		break;

	default:
		err = -EINVAL;
		goto out;
	}
	switch (ch_cfg->active) {
	case 0:
		break;
	case 1:
		*cfg |= (1 << 17);
		break;

	default:
		err = -EINVAL;
		goto out;
	}
	switch (ch_cfg->lock) {
	case 0:
		break;
	case 1:
		*cfg |= (1 << 16);
		break;