[linux-2.6-block.git] / arch / arm / mach-spear / pl080.c

/*
 * arch/arm/plat-spear/pl080.c
 *
 * DMAC pl080 definitions for SPEAr platform
 *
 * Copyright (C) 2012 ST Microelectronics
 * Viresh Kumar <vireshk@kernel.org>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/amba/pl08x.h>
#include <linux/amba/bus.h>
#include <linux/bug.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/spinlock_types.h>
#include <mach/spear.h>
#include <mach/misc_regs.h>

static spinlock_t lock = __SPIN_LOCK_UNLOCKED(x);

struct {
	unsigned char busy;
	unsigned char val;
} signals[16] = {{0, 0}, };

int pl080_get_signal(const struct pl08x_channel_data *cd)
{
	unsigned int signal = cd->min_signal, val;
	unsigned long flags;

	spin_lock_irqsave(&lock, flags);

	/* Return if signal is already acquired by somebody else */
	if (signals[signal].busy &&
			(signals[signal].val != cd->muxval)) {
		spin_unlock_irqrestore(&lock, flags);
		return -EBUSY;
	}

	/* If acquiring for the first time, configure it */
	if (!signals[signal].busy) {
		val = readl(DMA_CHN_CFG);

		/*
		 * Each request line has two bits in DMA_CHN_CFG register. To
		 * goto the bits of current request line, do left shift of
		 * value by 2 * signal number.
		 */
		val &= ~(0x3 << (signal * 2));
		val |= cd->muxval << (signal * 2);
		writel(val, DMA_CHN_CFG);
	}

	signals[signal].busy++;
	signals[signal].val = cd->muxval;
	spin_unlock_irqrestore(&lock, flags);

	return signal;
}

void pl080_put_signal(const struct pl08x_channel_data *cd, int signal)
{
	unsigned long flags;

	spin_lock_irqsave(&lock, flags);

	/* if signal is not used */
	if (!signals[signal].busy)
		BUG();

	signals[signal].busy--;

	spin_unlock_irqrestore(&lock, flags);
}
Commit	Line	Data
0b7ee717 VK	1	/*
	2	* arch/arm/plat-spear/pl080.c
	3	*
	4	* DMAC pl080 definitions for SPEAr platform
	5	*
	6	* Copyright (C) 2012 ST Microelectronics
da89947b	7	* Viresh Kumar <vireshk@kernel.org>
0b7ee717 VK	8	*
	9	* This file is licensed under the terms of the GNU General Public
	10	* License version 2. This program is licensed "as is" without any
	11	* warranty of any kind, whether express or implied.
	12	*/
	13
	14	#include <linux/amba/pl08x.h>
	15	#include <linux/amba/bus.h>
	16	#include <linux/bug.h>
	17	#include <linux/err.h>
	18	#include <linux/io.h>
	19	#include <linux/spinlock_types.h>
5019f0b1	20	#include <mach/spear.h>
0b7ee717 VK	21	#include <mach/misc_regs.h>
	22
	23	static spinlock_t lock = __SPIN_LOCK_UNLOCKED(x);
	24
	25	struct {
	26	unsigned char busy;
	27	unsigned char val;
	28	} signals[16] = {{0, 0}, };
	29
a8fb688e	30	int pl080_get_signal(const struct pl08x_channel_data *cd)
0b7ee717	31	{
0b7ee717 VK	32	unsigned int signal = cd->min_signal, val;
	33	unsigned long flags;
	34
	35	spin_lock_irqsave(&lock, flags);
	36
	37	/* Return if signal is already acquired by somebody else */
	38	if (signals[signal].busy &&
	39	(signals[signal].val != cd->muxval)) {
	40	spin_unlock_irqrestore(&lock, flags);
	41	return -EBUSY;
	42	}
	43
	44	/* If acquiring for the first time, configure it */
	45	if (!signals[signal].busy) {
	46	val = readl(DMA_CHN_CFG);
	47
	48	/*
	49	* Each request line has two bits in DMA_CHN_CFG register. To
	50	* goto the bits of current request line, do left shift of
	51	* value by 2 * signal number.
	52	*/
	53	val &= ~(0x3 << (signal * 2));
	54	val \|= cd->muxval << (signal * 2);
	55	writel(val, DMA_CHN_CFG);
	56	}
	57
	58	signals[signal].busy++;
	59	signals[signal].val = cd->muxval;
	60	spin_unlock_irqrestore(&lock, flags);
	61
	62	return signal;
	63	}
	64
a8fb688e	65	void pl080_put_signal(const struct pl08x_channel_data *cd, int signal)
0b7ee717	66	{
0b7ee717 VK	67	unsigned long flags;
	68
	69	spin_lock_irqsave(&lock, flags);
	70
	71	/* if signal is not used */
a8fb688e	72	if (!signals[signal].busy)
0b7ee717 VK	73	BUG();
0b7ee717 VK	74
a8fb688e	75	signals[signal].busy--;
0b7ee717 VK	76
	77	spin_unlock_irqrestore(&lock, flags);
	78	}