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Commit e2d1864d authored by Paul Mundt's avatar Paul Mundt
Browse files

sh: G2 DMA IRQ and residue sampling. 



This fixes a long-standing FIXME for G2 DMA, where we finally
wire up the IRQ handler and allow for sampling remaining bytes
while in-flight.

Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent ade2b3f6

arch/sh/drivers/dma/dma-g2.c

+41 −13
Original line number Diff line number Diff line
@@ -3,7 +3,7 @@ 
 *

 * G2 bus DMA support

 *

 * Copyright (C) 2003, 2004  Paul Mundt

 * Copyright (C) 2003 - 2006  Paul Mundt

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive
@@ -13,7 +13,7 @@ 
#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/interrupt.h>



#include <asm/cacheflush.h>

#include <asm/mach/sysasic.h>

#include <asm/mach/dma.h>

#include <asm/dma.h>
@@ -47,17 +47,31 @@ struct g2_dma_info { 


static volatile struct g2_dma_info *g2_dma = (volatile struct g2_dma_info *)0xa05f7800;



#define g2_bytes_remaining(i) \

	((g2_dma->channel[i].size - \

	  g2_dma->status[i].size) & 0x0fffffff)



static irqreturn_t g2_dma_interrupt(int irq, void *dev_id, struct pt_regs *regs)

{

	/* FIXME: Do some meaningful completion work here.. */

	int i;



	for (i = 0; i < G2_NR_DMA_CHANNELS; i++) {

		if (g2_dma->status[i].status & 0x20000000) {

			unsigned int bytes = g2_bytes_remaining(i);



			if (likely(bytes == 0)) {

				struct dma_info *info = dev_id;

				struct dma_channel *chan = info->channels + i;



				wake_up(&chan->wait_queue);



				return IRQ_HANDLED;

			}

		}

	}



static struct irqaction g2_dma_irq = {

	.name		= "g2 DMA handler",

	.handler	= g2_dma_interrupt,

	.flags		= IRQF_DISABLED,

};

	return IRQ_NONE;

}



static int g2_enable_dma(struct dma_channel *chan)

{
@@ -135,8 +149,14 @@ static int g2_xfer_dma(struct dma_channel *chan) 
	return 0;

}



static int g2_get_residue(struct dma_channel *chan)

{

	return g2_bytes_remaining(chan->chan);

}



static struct dma_ops g2_dma_ops = {

	.xfer		= g2_xfer_dma,

	.get_residue	= g2_get_residue,

};



static struct dma_info g2_dma_info = {
@@ -148,13 +168,22 @@ static struct dma_info g2_dma_info = { 


static int __init g2_dma_init(void)

{

	setup_irq(HW_EVENT_G2_DMA, &g2_dma_irq);

	int ret;



	ret = request_irq(HW_EVENT_G2_DMA, g2_dma_interrupt, IRQF_DISABLED,

			  "g2 DMA handler", &g2_dma_info);

	if (unlikely(ret))

		return -EINVAL;



	/* Magic */

	g2_dma->wait_state	= 27;

	g2_dma->magic		= 0x4659404f;



	return register_dmac(&g2_dma_info);

	ret = register_dmac(&g2_dma_info);

	if (unlikely(ret != 0))

		free_irq(HW_EVENT_G2_DMA, 0);



	return ret;

}



static void __exit g2_dma_exit(void)
@@ -169,4 +198,3 @@ module_exit(g2_dma_exit); 
MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");

MODULE_DESCRIPTION("G2 bus DMA driver");

MODULE_LICENSE("GPL");