omap3_dma.c
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/* Copyright (C) 2011
* Corscience GmbH & Co. KG - Simon Schwarz <schwarz@corscience.de>
*
* SPDX-License-Identifier: GPL-2.0+
*/
/* This is a basic implementation of the SDMA/DMA4 controller of OMAP3
* Tested on Silicon Revision major:0x4 minor:0x0
*/
#include <common.h>
#include <asm/arch/cpu.h>
#include <asm/arch/omap3.h>
#include <asm/arch/dma.h>
#include <asm/io.h>
#include <asm/errno.h>
static struct dma4 *dma4_cfg = (struct dma4 *)OMAP34XX_DMA4_BASE;
uint32_t dma_active; /* if a transfer is started the respective
bit is set for the logical channel */
/* Check if we have the given channel
* PARAMETERS:
* chan: Channel number
*
* RETURN of non-zero means error */
static inline int check_channel(uint32_t chan)
{
if (chan < CHAN_NR_MIN || chan > CHAN_NR_MAX)
return -EINVAL;
return 0;
}
static inline void reset_irq(uint32_t chan)
{
/* reset IRQ reason */
writel(0x1DFE, &dma4_cfg->chan[chan].csr);
/* reset IRQ */
writel((1 << chan), &dma4_cfg->irqstatus_l[0]);
dma_active &= ~(1 << chan);
}
/* Set Source, Destination and Size of DMA transfer for the
* specified channel.
* PARAMETERS:
* chan: channel to use
* src: source of the transfer
* dst: destination of the transfer
* sze: Size of the transfer
*
* RETURN of non-zero means error */
int omap3_dma_conf_transfer(uint32_t chan, uint32_t *src, uint32_t *dst,
uint32_t sze)
{
if (check_channel(chan))
return -EINVAL;
/* CDSA0 */
writel((uint32_t)src, &dma4_cfg->chan[chan].cssa);
writel((uint32_t)dst, &dma4_cfg->chan[chan].cdsa);
writel(sze, &dma4_cfg->chan[chan].cen);
return 0;
}
/* Start the DMA transfer */
int omap3_dma_start_transfer(uint32_t chan)
{
uint32_t val;
if (check_channel(chan))
return -EINVAL;
val = readl(&dma4_cfg->chan[chan].ccr);
/* Test for channel already in use */
if (val & CCR_ENABLE_ENABLE)
return -EBUSY;
writel((val | CCR_ENABLE_ENABLE), &dma4_cfg->chan[chan].ccr);
dma_active |= (1 << chan);
debug("started transfer...\n");
return 0;
}
/* Busy-waiting for a DMA transfer
* This has to be called before another transfer is started
* PARAMETER
* chan: Channel to wait for
*
* RETURN of non-zero means error*/
int omap3_dma_wait_for_transfer(uint32_t chan)
{
uint32_t val;
if (!(dma_active & (1 << chan))) {
val = readl(&dma4_cfg->irqstatus_l[0]);
if (!(val & chan)) {
debug("dma: The channel you are trying to wait for "
"was never activated - ERROR\n");
return -1; /* channel was never active */
}
}
/* all irqs on line 0 */
while (!(readl(&dma4_cfg->irqstatus_l[0]) & (1 << chan)))
asm("nop");
val = readl(&dma4_cfg->chan[chan].csr);
if ((val & CSR_TRANS_ERR) | (val & CSR_SUPERVISOR_ERR) |
(val & CSR_MISALIGNED_ADRS_ERR)) {
debug("err code: %X\n", val);
debug("dma: transfer error detected\n");
reset_irq(chan);
return -1;
}
reset_irq(chan);
return 0;
}
/* Get the revision of the DMA module
* PARAMETER
* minor: Address of minor revision to write
* major: Address of major revision to write
*
* RETURN of non-zero means error
*/
int omap3_dma_get_revision(uint32_t *minor, uint32_t *major)
{
uint32_t val;
/* debug information */
val = readl(&dma4_cfg->revision);
*major = (val & 0x000000F0) >> 4;
*minor = (val & 0x0000000F);
debug("DMA Silicon revision (maj/min): 0x%X/0x%X\n", *major, *minor);
return 0;
}
/* Initial config of omap dma
*/
void omap3_dma_init(void)
{
dma_active = 0;
/* All interrupts on channel 0 */
writel(0xFFFFFFFF, &dma4_cfg->irqenable_l[0]);
}
/* set channel config to config
*
* RETURN of non-zero means error */
int omap3_dma_conf_chan(uint32_t chan, struct dma4_chan *config)
{
if (check_channel(chan))
return -EINVAL;
dma4_cfg->chan[chan] = *config;
return 0;
}
/* get channel config to config
*
* RETURN of non-zero means error */
int omap3_dma_get_conf_chan(uint32_t chan, struct dma4_chan *config)
{
if (check_channel(chan))
return -EINVAL;
*config = dma4_cfg->chan[chan];
return 0;
}