// SPDX-License-Identifier: GPL-2.0
/*
* Core driver for the Synopsys DesignWare DMA Controller
*
* Copyright (C) 2007-2008 Atmel Corporation
* Copyright (C) 2010-2011 ST Microelectronics
* Copyright (C) 2013 Intel Corporation
*/
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>
#include "../dmaengine.h"
#include "internal.h"
/*
* This supports the Synopsys "DesignWare AHB Central DMA Controller",
* (DW_ahb_dmac) which is used with various AMBA 2.0 systems (not all
* of which use ARM any more). See the "Databook" from Synopsys for
* information beyond what licensees probably provide.
*
* The driver has been tested with the Atmel AT32AP7000, which does not
* support descriptor writeback.
*/
/* The set of bus widths supported by the DMA controller */
#define DW_DMA_BUSWIDTHS \
BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) | \
BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
BIT(DMA_SLAVE_BUSWIDTH_4_BYTES)
/*----------------------------------------------------------------------*/
static struct device *chan2dev(struct dma_chan *chan)
{
return &chan->dev->device;
}
static struct dw_desc *dwc_first_active(struct dw_dma_chan *dwc)
{
return to_dw_desc(dwc->active_list.next);
}
static dma_cookie_t dwc_tx_submit(struct dma_async_tx_descriptor *tx)
{
struct dw_desc *desc = txd_to_dw_desc(tx);
struct dw_dma_chan *dwc = to_dw_dma_chan(tx->chan);
dma_cookie_t cookie;
unsigned long flags;
spin_lock_irqsave(&dwc->lock, flags);
cookie = dma_cookie_assign(tx);
/*
* REVISIT: We should attempt to chain as many descriptors as
* possible, perhaps even appending to those already submitted
* for DMA. But this is hard to do in a race-free manner.
*/
list_add_tail(&desc->desc_node, &dwc->queue);
spin_unlock_irqrestore(&dwc->lock, flags);
dev_vdbg(chan2dev(tx->chan), "%s: queued %u\n",
__func__, desc->txd.cookie);
return cookie;
}
static struct dw_desc *dwc_desc_get(struct dw_dma_chan *dwc)
{
struct dw_dma *dw = to_dw_dma(dwc->chan.device);
struct dw_desc *desc;
dma_addr_t phys;
desc = dma_pool_zalloc(dw->desc_pool, GFP_ATOMIC, &phys);
if (!desc)
return NULL;
dwc->descs_allocated++;