/* linux/drivers/dma/pl330.c
*
* Copyright (C) 2010 Samsung Electronics Co. Ltd.
* Jaswinder Singh <jassi.brar@samsung.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/io.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/dmaengine.h>
#include <linux/interrupt.h>
#include <linux/amba/bus.h>
#include <linux/amba/pl330.h>
#include <linux/pm_runtime.h>
#include <linux/scatterlist.h>
#include <linux/of.h>
#define NR_DEFAULT_DESC 16
enum desc_status {
/* In the DMAC pool */
FREE,
/*
* Allocted to some channel during prep_xxx
* Also may be sitting on the work_list.
*/
PREP,
/*
* Sitting on the work_list and already submitted
* to the PL330 core. Not more than two descriptors
* of a channel can be BUSY at any time.
*/
BUSY,
/*
* Sitting on the channel work_list but xfer done
* by PL330 core
*/
DONE,
};
struct dma_pl330_chan {
/* Schedule desc completion */
struct tasklet_struct task;
/* DMA-Engine Channel */
struct dma_chan chan;
/* Last completed cookie */
dma_cookie_t completed;
/* List of to be xfered descriptors */
struct list_head work_list;
/* Pointer to the DMAC that manages this channel,
* NULL if the channel is available to be acquired.
* As the parent, this DMAC also provides descriptors
* to the channel.
*/
struct dma_pl330_dmac *dmac;
/* To protect channel manipulation */
spinlock_t lock;
/* Token of a hardware channel thread of PL330 DMAC
* NULL if the channel is available to be acquired.
*/
void *pl330_chid;
/* For D-to-M and M-to-D channels */
int burst_sz; /* the peripheral fifo width */
int burst_len; /* the number of burst */
dma_addr_t fifo_addr;
/* for cyclic capability */
bool cyclic;
};
struct dma_pl330_dmac {
struct pl330_info pif;
/* DMA-Engine Device */
struct dma_device ddma;
/* Pool of descriptors available for the DMAC's channels */
struct list_head desc_pool;
/* To protect desc_pool manipulation */
spinlock_t pool_lock;
/* Peripheral channels connected to this DMAC */
struct dma_pl330_chan *peripherals; /* keep at end */
struct clk *clk;
};
struct dma_pl330_desc {
/* To attach to a queue as child */
struct list_head node;
/* Descriptor for the DMA Engine API */
struct dma_async_tx_descriptor txd;
/* Xfer for PL330 core */
struct pl330_xfer px;
struct pl330_reqcfg rqcfg;
struct pl330_req req;
enum desc_status status;
/* The channel which currently holds this desc */
struct dma_pl330_chan *pchan;
};
/* forward declaration */
static struct amba_driver pl330_driver;
static inline struct dma_pl330_chan *
to_pchan(struct dma_chan *ch)
{
if (!ch)
return NULL;
return container_of(ch, struct dma_pl330_chan, chan);
}
static inline struct dma_pl330_desc *
to_desc(struct dma_async_tx_descriptor *tx)
{
return container_of(tx, struct dma_pl330_desc, txd);
}
static inline void free_desc_list(struct list_head *list)
{
struct dma_pl330_dmac *pdmac;
struct dma_pl330_desc *desc;
struct dma_pl330_chan *pch;
unsigned long flags;
if (list_empty(list))
return;
/* Finish off the work list */
list_for_each_entry(desc, list, node) {
dma_async_tx_callback callback;
void *param;
/* All desc in a list belong to same channel */
pch = desc->pchan;
callback = desc->txd.callback;
param = desc->txd.callback_param;
if (callback)
callback(param);
desc->pchan = NULL;
}
pdmac = pch->dmac;
spin_lock_irqsave(&pdmac->pool_lock, flags);
list_splice_tail_init(list, &pdmac->desc_pool);
spin_unlock_irqrestore(&pdmac->pool_lock, flags);
}
static inline void handle_cyclic_desc_list(struct list_head *list)
{
struct dma_pl330_desc *desc;
struct dma_pl330_chan *pch;
unsigned long flags;
if (list_empty(list))
return;
list_for_each_entry(desc, list, node) {
dma_async_tx_callback callback;
/* Change status to reload it */
desc->status = PREP;
pch = desc->pchan;
callback = desc->txd.callback;
if (callback)
callback(desc->txd.callback_param);
}
spin_lock_irqsave(&pch->lock, flags);