DMA example

DMA example

[Philip Balister]

I am trying to setup a dma operation to copy memory from GPMC address 
space into RAM. The only examples using the omap-dma api use hardware 
triggers.

When I start a transfer, I end up with a DMA transaction error when I 
start the transfer.

Does anyone have a good example of a software transfer? Currently, I am 
tracing the omap dma api to see how things map into the registers ....

Philip

Re: DMA example

[Tony Lindgren]

* Philip Balister <philip@balister.org> [100224 11:31]:
> I am trying to setup a dma operation to copy memory from GPMC
> address space into RAM. The only examples using the omap-dma api use
> hardware triggers.
> 
> When I start a transfer, I end up with a DMA transaction error when
> I start the transfer.
> 
> Does anyone have a good example of a software transfer? Currently, I
> am tracing the omap dma api to see how things map into the registers
> ....

Enjoy the GPMC timings. I recommend attaching a logic analyzer there
to verify the things are right for the key lines if you have chance.

Hmm I thought the hardware triggers were optional in at least
drivers/usb/musb/tusb6010_omap.c.. Maybe I don't remember correctly.

Regards,

Tony

RE: DMA example

[Shilimkar, Santosh]

> -----Original Message-----
> From: linux-omap-owner@vger.kernel.org [mailto:linux-omap-owner@vger.kernel.org] On Behalf Of Philip
> Balister
> Sent: Thursday, February 25, 2010 1:04 AM
> To: linux-omap@vger.kernel.org
> Subject: DMA example
> 
> I am trying to setup a dma operation to copy memory from GPMC address
> space into RAM. The only examples using the omap-dma api use hardware
> triggers.
> 
What you mean by GPMC address space. Are you trying to DMA data from NAND/NOR
to SDRAM/SRAM ?

> When I start a transfer, I end up with a DMA transaction error when I
> start the transfer.
> 
> Does anyone have a good example of a software transfer? Currently, I am
> tracing the omap dma api to see how things map into the registers ....
> 
> Philip
> --
> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
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Re: DMA example

[Philip Balister]

On 02/24/2010 12:35 PM, Tony Lindgren wrote:
> * Philip Balister<philip@balister.org>  [100224 11:31]:
>> I am trying to setup a dma operation to copy memory from GPMC
>> address space into RAM. The only examples using the omap-dma api use
>> hardware triggers.
>>
>> When I start a transfer, I end up with a DMA transaction error when
>> I start the transfer.
>>
>> Does anyone have a good example of a software transfer? Currently, I
>> am tracing the omap dma api to see how things map into the registers
>> ....
>
> Enjoy the GPMC timings. I recommend attaching a logic analyzer there
> to verify the things are right for the key lines if you have chance.
>
> Hmm I thought the hardware triggers were optional in at least
> drivers/usb/musb/tusb6010_omap.c.. Maybe I don't remember correctly.

GPMC is easy :)

Basically, I have a device attached to a GPMC chip select and I need to 
read/write to it. The GPNC bit is fine, we'd just like to use the DMA 
controller to move the data.

Philip

Re: DMA example

[Tony Lindgren]

* Philip Balister <philip@balister.org> [100224 14:28]:
> On 02/24/2010 12:35 PM, Tony Lindgren wrote:
> >* Philip Balister<philip@balister.org>  [100224 11:31]:
> >>I am trying to setup a dma operation to copy memory from GPMC
> >>address space into RAM. The only examples using the omap-dma api use
> >>hardware triggers.
> >>
> >>When I start a transfer, I end up with a DMA transaction error when
> >>I start the transfer.
> >>
> >>Does anyone have a good example of a software transfer? Currently, I
> >>am tracing the omap dma api to see how things map into the registers
> >>....
> >
> >Enjoy the GPMC timings. I recommend attaching a logic analyzer there
> >to verify the things are right for the key lines if you have chance.
> >
> >Hmm I thought the hardware triggers were optional in at least
> >drivers/usb/musb/tusb6010_omap.c.. Maybe I don't remember correctly.
> 
> GPMC is easy :)

Sounds like you just got lucky! :)
 
> Basically, I have a device attached to a GPMC chip select and I need
> to read/write to it. The GPNC bit is fine, we'd just like to use the
> DMA controller to move the data.

That should work, at least there has been several memory-to-memory
dma test modules posted here over the years. Have you tried using
OMAP_DMA_NO_DEVICE for omap_request_dma? Also search for omap dmatest
or similar.

Tony

Re: DMA example

[Philip Balister]

On 02/24/2010 02:52 PM, Tony Lindgren wrote:
> * Philip Balister<philip@balister.org>  [100224 14:28]:
>> On 02/24/2010 12:35 PM, Tony Lindgren wrote:
>>> * Philip Balister<philip@balister.org>   [100224 11:31]:
>>>> I am trying to setup a dma operation to copy memory from GPMC
>>>> address space into RAM. The only examples using the omap-dma api use
>>>> hardware triggers.
>>>>
>>>> When I start a transfer, I end up with a DMA transaction error when
>>>> I start the transfer.
>>>>
>>>> Does anyone have a good example of a software transfer? Currently, I
>>>> am tracing the omap dma api to see how things map into the registers
>>>> ....
>>>
>>> Enjoy the GPMC timings. I recommend attaching a logic analyzer there
>>> to verify the things are right for the key lines if you have chance.
>>>
>>> Hmm I thought the hardware triggers were optional in at least
>>> drivers/usb/musb/tusb6010_omap.c.. Maybe I don't remember correctly.
>>
>> GPMC is easy :)
>
> Sounds like you just got lucky! :)

OK, I am using the 2K non-multiplexed mode atm :) Still I have a logic 
analyzer and am confident I can get the mux'd modes working. Burst is 
still a bit scary.

>> Basically, I have a device attached to a GPMC chip select and I need
>> to read/write to it. The GPNC bit is fine, we'd just like to use the
>> DMA controller to move the data.
>
> That should work, at least there has been several memory-to-memory
> dma test modules posted here over the years. Have you tried using
> OMAP_DMA_NO_DEVICE for omap_request_dma? Also search for omap dmatest
> or similar.

Thanks. This is suggesting I am on the right track, but the transfer 
still fails with: DMA transaction error with device 0.

The call to omap_set_dma_transfer_params adds these two args:

params->trigger, params->src_or_dst_synch);

I think they are more for hw synched transfers and set them to zero.

the src|dest param setting calls added the  params->src_ei, 
params->src_fi arguments. I've set these to 1.

Any more clues?

Philip

Re: DMA example

[Philip Balister]

On 02/24/2010 06:24 PM, Philip Balister wrote:
>
> Any more clues?

Never mind, I am an idiot. Not out of the woods, but things are 
happening again :)

Philip

RE: DMA example

[Shilimkar, Santosh]

[-- Attachment #1: Type: text/plain, Size: 689 bytes --]

> -----Original Message-----
> From: linux-omap-owner@vger.kernel.org [mailto:linux-omap-owner@vger.kernel.org] On Behalf Of Philip
> Balister
> Sent: Thursday, February 25, 2010 9:56 AM
> To: Tony Lindgren
> Cc: linux-omap@vger.kernel.org
> Subject: Re: DMA example
> 
> On 02/24/2010 06:24 PM, Philip Balister wrote:
> >
> > Any more clues?
> 
> Never mind, I am an idiot. Not out of the woods, but things are
> happening again :)
> 

Attached is the example module for memory to memory transfer. The module test
is for RAM to RAM but you can easily adapt to you need.

It's slightly old but should help you to set the dma parameters correctly

Regards,
Santosh


[-- Attachment #2: dmaunlnk.c --]
[-- Type: text/plain, Size: 8051 bytes --]

/*
 * /vobs/wtbu/OMAPSW_L/linux/test/device_driver_test/dma/test_code/dmatest.c
 *
 * Dma Test Module
 *
 * Copyright (C) 2004-2006 Texas Instruments, Inc.
 *
 * This package 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.
 *
 * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/sched.h>

#include <asm/io.h>

#include <linux/version.h>

/********************** KERNEL SPECIFIC STUFF *****************/
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,00))
 #include <linux/dma-mapping.h>
#endif				/* kernel specs */

#include "dmatest.h"

#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,27))
 #include <mach/dma.h>
#else
 #include <asm/arch/dma.h>
#endif

/********************** GENERAL VARS *****************/
/* load-time options */
int debug = DEFAULT_DEBUG_LVL;
int channels = 2;
int maximum_transfers = 5;	/* max transfers per channel */
int buf_size = PAGE_SIZE;	/* Buffer size for each channel */
int prio = -1;
int burst = -1;
int query_idx = 0;

static struct dma_stat_id_s *stat_id;
static struct dma_buf_id_s *buf_id;

#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,00))
MODULE_PARM(debug, "i");
MODULE_PARM(channels, "i");
MODULE_PARM(maximum_transfers, "i");
MODULE_PARM(buf_size, "i");
#if defined(CONFIG_ARCH_OMAP24XX) || defined(CONFIG_ARCH_OMAP34XX)
MODULE_PARM(prio, "i");
MODULE_PARM(query_idx, "i");
MODULE_PARM(burst, "i");
#endif  // CONFIG_ARCH_OMAP24XX
#else
module_param(debug, int, 0444);
module_param(channels, int, 0444);
module_param(maximum_transfers, int, 0444);
module_param(buf_size, int, 0444);
#if defined(CONFIG_ARCH_OMAP24XX) || defined(CONFIG_ARCH_OMAP34XX)
module_param(prio, int, 0444);
module_param(burst, int, 0444);
module_param(query_idx, int, 0444);
#endif
#endif

struct dma_test_s {
	int dev_id;
	int dma_ch;
};
static struct dma_test_s dma_test[MAX_CHANNELS];

/********************** TEST LOGIC *****************/

static int get_lch(int channel)
{
	int i = 0;
	for (i = 0; i < MAX_CHANNELS; i++) {
		if (dma_test[i].dma_ch == channel)
			break;
	}
	if (i == MAX_CHANNELS)
		return -EPERM;
	return i;
}
static void dma_callback(int lch, u16 ch_status, void *data)
{
	struct dma_test_s *t = (struct dma_test_s *)data;
	int idx = get_lch(lch);
	int status = 1;
	FN_IN();

	printk("%d: ", lch);
	if (lch == t->dma_ch) {
		ch_status &= ~(OMAP_DMA_BLOCK_IRQ);
		if (!ch_status && !buf_verify(buf_id, idx, buf_size)) {
			printk("P\n");
			status = 0;
		} else {
			printk("F\n");
		}
		/* Dont care abt the continuing the transfer */
		(void)stat_update(stat_id, idx, status);

	} else {
		D(4, "dma_callback(): Unexpected event on channel %d", lch);
	}

#ifdef DMA_DUMP
	{
		int i;
		/* Dump all the dma registers for all channels */
		for (i = 0; i < channels; i++) {
			printk("CH %d\n", i);
			omap_dump_lch_reg(dma_test[i].dma_ch);
		}
	}
#endif
	FN_OUT(0);
}

static void __exit dmatest_cleanup(void)
{
	int i;

	FN_IN();
	for (i = 0; i < channels; i++) {
		if (dma_test[i].dma_ch >= 0) {
			omap_stop_dma(dma_test[i].dma_ch);
			omap_free_dma(dma_test[i].dma_ch);

			dma_test[i].dma_ch = -1;
		}
	}
	buf_free(buf_id, channels, buf_size);
	stat_exit(stat_id);
	FN_OUT(0);
}

static int __init dmatest_init(void)
{
	int i;
	int elem_count, frame_count;
	unsigned int src, dest;
	int ret = 0;

	FN_IN();
	if (channels > MAX_CHANNELS) {
		ERR("channels arg (%d) > MAX_CHANNELS (%d)\n",
		    channels, MAX_CHANNELS);
		FN_OUT(-ENODEV);
		return -ENODEV;
	}

	/* Alloc DMA-able buffers */
	if ((ret = buf_allocate(channels, buf_size, &buf_id))) {
		ERR(" Unable to find memory%d\n", ret);
		return ret;
	}
	/* Init statitistics */
	if ((ret = stat_init("dmaunlnk", channels, &stat_id))) {
		ERR(" Unable to proc init %d\n", ret);
		buf_free(buf_id, channels, buf_size);
		return ret;
	}

	for (i = 0; i < channels; i++) {
		D(3, "DMA test %d\n", i);

		/* Setup DMA transfer */
		dma_test[i].dev_id = OMAP_DMA_NO_DEVICE;
		dma_test[i].dma_ch = -1;
		ret = omap_request_dma(dma_test[i].dev_id, "DMA Test",
				       dma_callback, (void *)&dma_test[i],
				       &dma_test[i].dma_ch);
		if (ret) {
			ERR("request_dma() failed: %d\n", ret);
			dma_test[i].dev_id = 0;
			D(4, "WARNING: Only go %d/%d channels.\n", i, channels);
			channels = i;
			break;
		}

		/* Set stat initialization */
		stat_set_transfer(stat_id, i, dma_test[i].dma_ch, 0);
		/* src buf init */
		D(2, "   pre-filling src buf %d\n", i);
		(void)buf_fill(buf_id, i, dma_test[i].dma_ch, buf_size);	/* dont expect this to die .. yet */
		/* grab the physical pointers */
		(void)buf_get_src_dst_phy(buf_id, i, &src, &dest);
		D(2, "physical address src=0x%08x 0x%08x\n", src, dest);

		elem_count = buf_size / 4;
		frame_count = 1;
#if defined(CONFIG_ARCH_OMAP24XX) || defined(CONFIG_ARCH_OMAP34XX)
		/* 24XX params */
		omap_set_dma_transfer_params(dma_test[i].dma_ch,	/* int lch */
					     OMAP_DMA_DATA_TYPE_S32,	/* int data_type */
					     elem_count,	/* int elem_count */
					     frame_count,	/* int frame_count */
					     OMAP_DMA_SYNC_ELEMENT,	/*  int sync_mode */
					     dma_test[i].dev_id,	/* int dma_trigger */
					     0x0);	/* int src_or_dst_synch */
		omap_set_dma_src_params(dma_test[i].dma_ch,	/* int lch */
					0, /* Port only for OMAP1 */
					OMAP_DMA_AMODE_POST_INC,	/* post increment int src_amode */
					src,	/*  int src_start */
					0x0,	/*  int src_ei */
					0x0);	/* int src_fi */
		omap_set_dma_dest_params(dma_test[i].dma_ch,	/* int lch */
					0, /* Port only for OMAP1 */
					 OMAP_DMA_AMODE_POST_INC,	/* post increment int dst_amode */
					 dest,	/*  int dst_start */
					 0x0,	/*  int dst_ei */
					 0x0);	/* int dst_fi */
		if (burst >= 0) {
			omap_set_dma_src_burst_mode(dma_test[i].dma_ch,
							OMAP_DMA_DATA_BURST_4);
			omap_set_dma_dest_burst_mode(dma_test[i].dma_ch,
							OMAP_DMA_DATA_BURST_4);
		}
#else
		/* 16XX params */
		omap_set_dma_transfer_params(dma_test[i].dma_ch,
					     OMAP_DMA_DATA_TYPE_S32,
					     elem_count,
					     frame_count,
					     OMAP_DMA_SYNC_ELEMENT);
		omap_set_dma_src_params(dma_test[i].dma_ch, OMAP_DMA_PORT_EMIFF,
					OMAP_DMA_AMODE_POST_INC, src);
		omap_set_dma_dest_params(dma_test[i].dma_ch,
					 OMAP_DMA_PORT_EMIFF,
					 OMAP_DMA_AMODE_POST_INC, dest);
#endif

	}

#if defined(CONFIG_ARCH_OMAP24XX) || defined(CONFIG_ARCH_OMAP34XX)
	/* set the priority settings  priority of a single channel alone now.. */
	if (prio >= 0) {
		D(2, "Priority to %d 25%% channel reserved ", prio);
		omap_dma_set_global_params(DMA_DEFAULT_ARB_RATE,
					  DMA_DEFAULT_FIFO_DEPTH,
					  DMA_THREAD_RESERVE_ONET |
					  DMA_THREAD_FIFO_25);
		omap_dma_set_prio_lch(dma_test[prio].dma_ch, DMA_CH_PRIO_HIGH,
				      DMA_CH_PRIO_HIGH);
	}
#endif
	for (i = 0; i < channels; i++) {
		D(3, "   2Start DMA channel %d\n", dma_test[i].dma_ch);
		omap_start_dma(dma_test[i].dma_ch);
	}
	udelay(10);

	if (query_idx) {
		int lh = 0;
		int lch = 0;
		int src[MAX_CHANNELS];
		int dst[MAX_CHANNELS];
	//	int ei[MAX_CHANNELS];
	//	int fi[MAX_CHANNELS];
		for (lh = 0; lh < channels; lh++) {
			lch = dma_test[lh].dma_ch;
			src[lh] = omap_get_dma_src_pos(lch);
			dst[lh] = omap_get_dma_dst_pos(lch);
	//		if (unlikely
	//		    (omap_get_dma_index(lch, &(ei[lh]), &(fi[lh])))) {
	//			printk("lch-%d fialed src indx\n", lch);
	//		}
		}
		printk("idx[lch]-> [src]        [dst]        [ei/fi] \n");
		for (lch = 0; lch < channels; lch++) {
			printk
			    ("%02d [%02d] -> [0x%08X] [0x%08X] \n",		//[0x%08X/0x%08X]\n",
			     lch, dma_test[lch].dma_ch, src[lch], dst[lch]);//
	//		     ,ei[lch], fi[lch]);
		}
	}
	FN_OUT(0);
	return 0;
}

module_init(dmatest_init);
module_exit(dmatest_cleanup);

MODULE_AUTHOR("Texas Instruments");
MODULE_LICENSE("GPL");

Re: DMA example

[Venkatraman S]

On Thu, Feb 25, 2010 at 7:54 AM, Philip Balister <philip@balister.org> wrote:
> On 02/24/2010 02:52 PM, Tony Lindgren wrote:
>>
>> * Philip Balister<philip@balister.org>  [100224 14:28]:
>>>
>>> On 02/24/2010 12:35 PM, Tony Lindgren wrote:
>>>>
>>>> * Philip Balister<philip@balister.org>   [100224 11:31]:
>>>>>
>>>>> I am trying to setup a dma operation to copy memory from GPMC
>>>>> address space into RAM. The only examples using the omap-dma api use
>>>>> hardware triggers.
>>>>>
>>>>> When I start a transfer, I end up with a DMA transaction error when
>>>>> I start the transfer.
>>>>>
>>>>> Does anyone have a good example of a software transfer? Currently, I
>>>>> am tracing the omap dma api to see how things map into the registers
>>>>> ....

For the record, some unit tests for OMAP device drivers are available at
http://dev.omapzoom.org/?p=richo/device_driver_test.git;a=summary.
In dma/test_code/utils/dma/dma_addrmode_doubleidx.c, there's normal
memory to memory transfer example..
Most of the omap_dma* api calls are done via dma_single_channel.c file.

Hope this helps,

Venkat.
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