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at_hdmac.c
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/*
* Driver for the Atmel AHB DMA Controller (aka HDMA or DMAC on AT91 systems)
*
* Copyright (C) 2008 Atmel Corporation
*
* 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.
*
*
* This supports the Atmel AHB DMA Controller found in several Atmel SoCs.
* The only Atmel DMA Controller that is not covered by this driver is the one
* found on AT91SAM9263.
*/
#include <dt-bindings/dma/at91.h>
#include <linux/clk.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_dma.h>
#include "at_hdmac_regs.h"
#include "dmaengine.h"
/*
* Glossary
* --------
*
* at_hdmac : Name of the ATmel AHB DMA Controller
* at_dma_ / atdma : ATmel DMA controller entity related
* atc_ / atchan : ATmel DMA Channel entity related
*/
#define ATC_DEFAULT_CFG (ATC_FIFOCFG_HALFFIFO)
#define ATC_DEFAULT_CTRLB (ATC_SIF(AT_DMA_MEM_IF) \
|ATC_DIF(AT_DMA_MEM_IF))
#define ATC_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))
#define ATC_MAX_DSCR_TRIALS 10
/*
* Initial number of descriptors to allocate for each channel. This could
* be increased during dma usage.
*/
static unsigned int init_nr_desc_per_channel = 64;
module_param(init_nr_desc_per_channel, uint, 0644);
MODULE_PARM_DESC(init_nr_desc_per_channel,
"initial descriptors per channel (default: 64)");
/* prototypes */
static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx);
static void atc_issue_pending(struct dma_chan *chan);
/*----------------------------------------------------------------------*/
static inline unsigned int atc_get_xfer_width(dma_addr_t src, dma_addr_t dst,
size_t len)
{
unsigned int width;
if (!((src | dst | len) & 3))
width = 2;
else if (!((src | dst | len) & 1))
width = 1;
else
width = 0;
return width;
}
static struct at_desc *atc_first_active(struct at_dma_chan *atchan)
{
return list_first_entry(&atchan->active_list,
struct at_desc, desc_node);
}
static struct at_desc *atc_first_queued(struct at_dma_chan *atchan)
{
return list_first_entry(&atchan->queue,
struct at_desc, desc_node);
}
/**
* atc_alloc_descriptor - allocate and return an initialized descriptor
* @chan: the channel to allocate descriptors for
* @gfp_flags: GFP allocation flags
*
* Note: The ack-bit is positioned in the descriptor flag at creation time
* to make initial allocation more convenient. This bit will be cleared
* and control will be given to client at usage time (during
* preparation functions).
*/
static struct at_desc *atc_alloc_descriptor(struct dma_chan *chan,
gfp_t gfp_flags)
{
struct at_desc *desc = NULL;
struct at_dma *atdma = to_at_dma(chan->device);
dma_addr_t phys;
desc = dma_pool_alloc(atdma->dma_desc_pool, gfp_flags, &phys);
if (desc) {
memset(desc, 0, sizeof(struct at_desc));
INIT_LIST_HEAD(&desc->tx_list);
dma_async_tx_descriptor_init(&desc->txd, chan);
/* txd.flags will be overwritten in prep functions */
desc->txd.flags = DMA_CTRL_ACK;
desc->txd.tx_submit = atc_tx_submit;
desc->txd.phys = phys;
}
return desc;
}
/**
* atc_desc_get - get an unused descriptor from free_list
* @atchan: channel we want a new descriptor for
*/
static struct at_desc *atc_desc_get(struct at_dma_chan *atchan)
{
struct at_desc *desc, *_desc;
struct at_desc *ret = NULL;
unsigned long flags;
unsigned int i = 0;
LIST_HEAD(tmp_list);
spin_lock_irqsave(&atchan->lock, flags);
list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) {
i++;
if (async_tx_test_ack(&desc->txd)) {
list_del(&desc->desc_node);
ret = desc;
break;
}
dev_dbg(chan2dev(&atchan->chan_common),
"desc %p not ACKed\n", desc);
}
spin_unlock_irqrestore(&atchan->lock, flags);
dev_vdbg(chan2dev(&atchan->chan_common),
"scanned %u descriptors on freelist\n", i);
/* no more descriptor available in initial pool: create one more */
if (!ret) {
ret = atc_alloc_descriptor(&atchan->chan_common, GFP_ATOMIC);
if (ret) {
spin_lock_irqsave(&atchan->lock, flags);
atchan->descs_allocated++;
spin_unlock_irqrestore(&atchan->lock, flags);
} else {
dev_err(chan2dev(&atchan->chan_common),
"not enough descriptors available\n");
}
}
return ret;
}
/**
* atc_desc_put - move a descriptor, including any children, to the free list
* @atchan: channel we work on
* @desc: descriptor, at the head of a chain, to move to free list
*/
static void atc_desc_put(struct at_dma_chan *atchan, struct at_desc *desc)
{
if (desc) {
struct at_desc *child;
unsigned long flags;
spin_lock_irqsave(&atchan->lock, flags);
list_for_each_entry(child, &desc->tx_list, desc_node)
dev_vdbg(chan2dev(&atchan->chan_common),
"moving child desc %p to freelist\n",
child);
list_splice_init(&desc->tx_list, &atchan->free_list);
dev_vdbg(chan2dev(&atchan->chan_common),
"moving desc %p to freelist\n", desc);
list_add(&desc->desc_node, &atchan->free_list);
spin_unlock_irqrestore(&atchan->lock, flags);
}
}
/**
* atc_desc_chain - build chain adding a descriptor
* @first: address of first descriptor of the chain
* @prev: address of previous descriptor of the chain
* @desc: descriptor to queue
*
* Called from prep_* functions
*/
static void atc_desc_chain(struct at_desc **first, struct at_desc **prev,
struct at_desc *desc)
{
if (!(*first)) {
*first = desc;
} else {
/* inform the HW lli about chaining */
(*prev)->lli.dscr = desc->txd.phys;
/* insert the link descriptor to the LD ring */
list_add_tail(&desc->desc_node,
&(*first)->tx_list);
}
*prev = desc;
}
/**
* atc_dostart - starts the DMA engine for real
* @atchan: the channel we want to start
* @first: first descriptor in the list we want to begin with
*
* Called with atchan->lock held and bh disabled
*/
static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first)
{
struct at_dma *atdma = to_at_dma(atchan->chan_common.device);
/* ASSERT: channel is idle */
if (atc_chan_is_enabled(atchan)) {
dev_err(chan2dev(&atchan->chan_common),
"BUG: Attempted to start non-idle channel\n");
dev_err(chan2dev(&atchan->chan_common),
" channel: s0x%x d0x%x ctrl0x%x:0x%x l0x%x\n",
channel_readl(atchan, SADDR),
channel_readl(atchan, DADDR),
channel_readl(atchan, CTRLA),
channel_readl(atchan, CTRLB),
channel_readl(atchan, DSCR));
/* The tasklet will hopefully advance the queue... */
return;
}
vdbg_dump_regs(atchan);
channel_writel(atchan, SADDR, 0);
channel_writel(atchan, DADDR, 0);
channel_writel(atchan, CTRLA, 0);
channel_writel(atchan, CTRLB, 0);
channel_writel(atchan, DSCR, first->txd.phys);
channel_writel(atchan, SPIP, ATC_SPIP_HOLE(first->src_hole) |
ATC_SPIP_BOUNDARY(first->boundary));
channel_writel(atchan, DPIP, ATC_DPIP_HOLE(first->dst_hole) |
ATC_DPIP_BOUNDARY(first->boundary));
dma_writel(atdma, CHER, atchan->mask);
vdbg_dump_regs(atchan);
}
/*
* atc_get_desc_by_cookie - get the descriptor of a cookie
* @atchan: the DMA channel
* @cookie: the cookie to get the descriptor for
*/
static struct at_desc *atc_get_desc_by_cookie(struct at_dma_chan *atchan,
dma_cookie_t cookie)
{
struct at_desc *desc, *_desc;
list_for_each_entry_safe(desc, _desc, &atchan->queue, desc_node) {
if (desc->txd.cookie == cookie)
return desc;
}
list_for_each_entry_safe(desc, _desc, &atchan->active_list, desc_node) {
if (desc->txd.cookie == cookie)
return desc;
}
return NULL;
}
/**
* atc_calc_bytes_left - calculates the number of bytes left according to the
* value read from CTRLA.
*
* @current_len: the number of bytes left before reading CTRLA
* @ctrla: the value of CTRLA
*/
static inline int atc_calc_bytes_left(int current_len, u32 ctrla)
{
u32 btsize = (ctrla & ATC_BTSIZE_MAX);
u32 src_width = ATC_REG_TO_SRC_WIDTH(ctrla);
/*
* According to the datasheet, when reading the Control A Register
* (ctrla), the Buffer Transfer Size (btsize) bitfield refers to the
* number of transfers completed on the Source Interface.
* So btsize is always a number of source width transfers.
*/
return current_len - (btsize << src_width);
}
/**
* atc_get_bytes_left - get the number of bytes residue for a cookie
* @chan: DMA channel
* @cookie: transaction identifier to check status of
*/
static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_desc *desc_first = atc_first_active(atchan);
struct at_desc *desc;
int ret;
u32 ctrla, dscr, trials;
/*
* If the cookie doesn't match to the currently running transfer then
* we can return the total length of the associated DMA transfer,
* because it is still queued.
*/
desc = atc_get_desc_by_cookie(atchan, cookie);
if (desc == NULL)
return -EINVAL;
else if (desc != desc_first)
return desc->total_len;
/* cookie matches to the currently running transfer */
ret = desc_first->total_len;
if (desc_first->lli.dscr) {
/* hardware linked list transfer */
/*
* Calculate the residue by removing the length of the child
* descriptors already transferred from the total length.
* To get the current child descriptor we can use the value of
* the channel's DSCR register and compare it against the value
* of the hardware linked list structure of each child
* descriptor.
*
* The CTRLA register provides us with the amount of data
* already read from the source for the current child
* descriptor. So we can compute a more accurate residue by also
* removing the number of bytes corresponding to this amount of
* data.
*
* However, the DSCR and CTRLA registers cannot be read both
* atomically. Hence a race condition may occur: the first read
* register may refer to one child descriptor whereas the second
* read may refer to a later child descriptor in the list
* because of the DMA transfer progression inbetween the two
* reads.
*
* One solution could have been to pause the DMA transfer, read
* the DSCR and CTRLA then resume the DMA transfer. Nonetheless,
* this approach presents some drawbacks:
* - If the DMA transfer is paused, RX overruns or TX underruns
* are more likey to occur depending on the system latency.
* Taking the USART driver as an example, it uses a cyclic DMA
* transfer to read data from the Receive Holding Register
* (RHR) to avoid RX overruns since the RHR is not protected
* by any FIFO on most Atmel SoCs. So pausing the DMA transfer
* to compute the residue would break the USART driver design.
* - The atc_pause() function masks interrupts but we'd rather
* avoid to do so for system latency purpose.
*
* Then we'd rather use another solution: the DSCR is read a
* first time, the CTRLA is read in turn, next the DSCR is read
* a second time. If the two consecutive read values of the DSCR
* are the same then we assume both refers to the very same
* child descriptor as well as the CTRLA value read inbetween
* does. For cyclic tranfers, the assumption is that a full loop
* is "not so fast".
* If the two DSCR values are different, we read again the CTRLA
* then the DSCR till two consecutive read values from DSCR are
* equal or till the maxium trials is reach.
* This algorithm is very unlikely not to find a stable value for
* DSCR.
*/
dscr = channel_readl(atchan, DSCR);
rmb(); /* ensure DSCR is read before CTRLA */
ctrla = channel_readl(atchan, CTRLA);
for (trials = 0; trials < ATC_MAX_DSCR_TRIALS; ++trials) {
u32 new_dscr;
rmb(); /* ensure DSCR is read after CTRLA */
new_dscr = channel_readl(atchan, DSCR);
/*
* If the DSCR register value has not changed inside the
* DMA controller since the previous read, we assume
* that both the dscr and ctrla values refers to the
* very same descriptor.
*/
if (likely(new_dscr == dscr))
break;
/*
* DSCR has changed inside the DMA controller, so the
* previouly read value of CTRLA may refer to an already
* processed descriptor hence could be outdated.
* We need to update ctrla to match the current
* descriptor.
*/
dscr = new_dscr;
rmb(); /* ensure DSCR is read before CTRLA */
ctrla = channel_readl(atchan, CTRLA);
}
if (unlikely(trials >= ATC_MAX_DSCR_TRIALS))
return -ETIMEDOUT;
/* for the first descriptor we can be more accurate */
if (desc_first->lli.dscr == dscr)
return atc_calc_bytes_left(ret, ctrla);
ret -= desc_first->len;
list_for_each_entry(desc, &desc_first->tx_list, desc_node) {
if (desc->lli.dscr == dscr)
break;
ret -= desc->len;
}
/*
* For the current descriptor in the chain we can calculate
* the remaining bytes using the channel's register.
*/
ret = atc_calc_bytes_left(ret, ctrla);
} else {
/* single transfer */
ctrla = channel_readl(atchan, CTRLA);
ret = atc_calc_bytes_left(ret, ctrla);
}
return ret;
}
/**
* atc_chain_complete - finish work for one transaction chain
* @atchan: channel we work on
* @desc: descriptor at the head of the chain we want do complete
*
* Called with atchan->lock held and bh disabled */
static void
atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
{
struct dma_async_tx_descriptor *txd = &desc->txd;
struct at_dma *atdma = to_at_dma(atchan->chan_common.device);
dev_vdbg(chan2dev(&atchan->chan_common),
"descriptor %u complete\n", txd->cookie);
/* mark the descriptor as complete for non cyclic cases only */
if (!atc_chan_is_cyclic(atchan))
dma_cookie_complete(txd);
/* If the transfer was a memset, free our temporary buffer */
if (desc->memset_buffer) {
dma_pool_free(atdma->memset_pool, desc->memset_vaddr,
desc->memset_paddr);
desc->memset_buffer = false;
}
/* move children to free_list */
list_splice_init(&desc->tx_list, &atchan->free_list);
/* move myself to free_list */
list_move(&desc->desc_node, &atchan->free_list);
dma_descriptor_unmap(txd);
/* for cyclic transfers,
* no need to replay callback function while stopping */
if (!atc_chan_is_cyclic(atchan)) {
/*
* The API requires that no submissions are done from a
* callback, so we don't need to drop the lock here
*/
dmaengine_desc_get_callback_invoke(txd, NULL);
}
dma_run_dependencies(txd);
}
/**
* atc_complete_all - finish work for all transactions
* @atchan: channel to complete transactions for
*
* Eventually submit queued descriptors if any
*
* Assume channel is idle while calling this function
* Called with atchan->lock held and bh disabled
*/
static void atc_complete_all(struct at_dma_chan *atchan)
{
struct at_desc *desc, *_desc;
LIST_HEAD(list);
dev_vdbg(chan2dev(&atchan->chan_common), "complete all\n");
/*
* Submit queued descriptors ASAP, i.e. before we go through
* the completed ones.
*/
if (!list_empty(&atchan->queue))
atc_dostart(atchan, atc_first_queued(atchan));
/* empty active_list now it is completed */
list_splice_init(&atchan->active_list, &list);
/* empty queue list by moving descriptors (if any) to active_list */
list_splice_init(&atchan->queue, &atchan->active_list);
list_for_each_entry_safe(desc, _desc, &list, desc_node)
atc_chain_complete(atchan, desc);
}
/**
* atc_advance_work - at the end of a transaction, move forward
* @atchan: channel where the transaction ended
*
* Called with atchan->lock held and bh disabled
*/
static void atc_advance_work(struct at_dma_chan *atchan)
{
dev_vdbg(chan2dev(&atchan->chan_common), "advance_work\n");
if (atc_chan_is_enabled(atchan))
return;
if (list_empty(&atchan->active_list) ||
list_is_singular(&atchan->active_list)) {
atc_complete_all(atchan);
} else {
atc_chain_complete(atchan, atc_first_active(atchan));
/* advance work */
atc_dostart(atchan, atc_first_active(atchan));
}
}
/**
* atc_handle_error - handle errors reported by DMA controller
* @atchan: channel where error occurs
*
* Called with atchan->lock held and bh disabled
*/
static void atc_handle_error(struct at_dma_chan *atchan)
{
struct at_desc *bad_desc;
struct at_desc *child;
/*
* The descriptor currently at the head of the active list is
* broked. Since we don't have any way to report errors, we'll
* just have to scream loudly and try to carry on.
*/
bad_desc = atc_first_active(atchan);
list_del_init(&bad_desc->desc_node);
/* As we are stopped, take advantage to push queued descriptors
* in active_list */
list_splice_init(&atchan->queue, atchan->active_list.prev);
/* Try to restart the controller */
if (!list_empty(&atchan->active_list))
atc_dostart(atchan, atc_first_active(atchan));
/*
* KERN_CRITICAL may seem harsh, but since this only happens
* when someone submits a bad physical address in a
* descriptor, we should consider ourselves lucky that the
* controller flagged an error instead of scribbling over
* random memory locations.
*/
dev_crit(chan2dev(&atchan->chan_common),
"Bad descriptor submitted for DMA!\n");
dev_crit(chan2dev(&atchan->chan_common),
" cookie: %d\n", bad_desc->txd.cookie);
atc_dump_lli(atchan, &bad_desc->lli);
list_for_each_entry(child, &bad_desc->tx_list, desc_node)
atc_dump_lli(atchan, &child->lli);
/* Pretend the descriptor completed successfully */
atc_chain_complete(atchan, bad_desc);
}
/**
* atc_handle_cyclic - at the end of a period, run callback function
* @atchan: channel used for cyclic operations
*
* Called with atchan->lock held and bh disabled
*/
static void atc_handle_cyclic(struct at_dma_chan *atchan)
{
struct at_desc *first = atc_first_active(atchan);
struct dma_async_tx_descriptor *txd = &first->txd;
dev_vdbg(chan2dev(&atchan->chan_common),
"new cyclic period llp 0x%08x\n",
channel_readl(atchan, DSCR));
dmaengine_desc_get_callback_invoke(txd, NULL);
}
/*-- IRQ & Tasklet ---------------------------------------------------*/
static void atc_tasklet(unsigned long data)
{
struct at_dma_chan *atchan = (struct at_dma_chan *)data;
unsigned long flags;
spin_lock_irqsave(&atchan->lock, flags);
if (test_and_clear_bit(ATC_IS_ERROR, &atchan->status))
atc_handle_error(atchan);
else if (atc_chan_is_cyclic(atchan))
atc_handle_cyclic(atchan);
else
atc_advance_work(atchan);
spin_unlock_irqrestore(&atchan->lock, flags);
}
static irqreturn_t at_dma_interrupt(int irq, void *dev_id)
{
struct at_dma *atdma = (struct at_dma *)dev_id;
struct at_dma_chan *atchan;
int i;
u32 status, pending, imr;
int ret = IRQ_NONE;
do {
imr = dma_readl(atdma, EBCIMR);
status = dma_readl(atdma, EBCISR);
pending = status & imr;
if (!pending)
break;
dev_vdbg(atdma->dma_common.dev,
"interrupt: status = 0x%08x, 0x%08x, 0x%08x\n",
status, imr, pending);
for (i = 0; i < atdma->dma_common.chancnt; i++) {
atchan = &atdma->chan[i];
if (pending & (AT_DMA_BTC(i) | AT_DMA_ERR(i))) {
if (pending & AT_DMA_ERR(i)) {
/* Disable channel on AHB error */
dma_writel(atdma, CHDR,
AT_DMA_RES(i) | atchan->mask);
/* Give information to tasklet */
set_bit(ATC_IS_ERROR, &atchan->status);
}
tasklet_schedule(&atchan->tasklet);
ret = IRQ_HANDLED;
}
}
} while (pending);
return ret;
}
/*-- DMA Engine API --------------------------------------------------*/
/**
* atc_tx_submit - set the prepared descriptor(s) to be executed by the engine
* @desc: descriptor at the head of the transaction chain
*
* Queue chain if DMA engine is working already
*
* Cookie increment and adding to active_list or queue must be atomic
*/
static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx)
{
struct at_desc *desc = txd_to_at_desc(tx);
struct at_dma_chan *atchan = to_at_dma_chan(tx->chan);
dma_cookie_t cookie;
unsigned long flags;
spin_lock_irqsave(&atchan->lock, flags);
cookie = dma_cookie_assign(tx);
if (list_empty(&atchan->active_list)) {
dev_vdbg(chan2dev(tx->chan), "tx_submit: started %u\n",
desc->txd.cookie);
atc_dostart(atchan, desc);
list_add_tail(&desc->desc_node, &atchan->active_list);
} else {
dev_vdbg(chan2dev(tx->chan), "tx_submit: queued %u\n",
desc->txd.cookie);
list_add_tail(&desc->desc_node, &atchan->queue);
}
spin_unlock_irqrestore(&atchan->lock, flags);
return cookie;
}
/**
* atc_prep_dma_interleaved - prepare memory to memory interleaved operation
* @chan: the channel to prepare operation on
* @xt: Interleaved transfer template
* @flags: tx descriptor status flags
*/
static struct dma_async_tx_descriptor *
atc_prep_dma_interleaved(struct dma_chan *chan,
struct dma_interleaved_template *xt,
unsigned long flags)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct data_chunk *first = xt->sgl;
struct at_desc *desc = NULL;
size_t xfer_count;
unsigned int dwidth;
u32 ctrla;
u32 ctrlb;
size_t len = 0;
int i;
if (unlikely(!xt || xt->numf != 1 || !xt->frame_size))
return NULL;
dev_info(chan2dev(chan),
"%s: src=%pad, dest=%pad, numf=%d, frame_size=%d, flags=0x%lx\n",
__func__, &xt->src_start, &xt->dst_start, xt->numf,
xt->frame_size, flags);
/*
* The controller can only "skip" X bytes every Y bytes, so we
* need to make sure we are given a template that fit that
* description, ie a template with chunks that always have the
* same size, with the same ICGs.
*/
for (i = 0; i < xt->frame_size; i++) {
struct data_chunk *chunk = xt->sgl + i;
if ((chunk->size != xt->sgl->size) ||
(dmaengine_get_dst_icg(xt, chunk) != dmaengine_get_dst_icg(xt, first)) ||
(dmaengine_get_src_icg(xt, chunk) != dmaengine_get_src_icg(xt, first))) {
dev_err(chan2dev(chan),
"%s: the controller can transfer only identical chunks\n",
__func__);
return NULL;
}
len += chunk->size;
}
dwidth = atc_get_xfer_width(xt->src_start,
xt->dst_start, len);
xfer_count = len >> dwidth;
if (xfer_count > ATC_BTSIZE_MAX) {
dev_err(chan2dev(chan), "%s: buffer is too big\n", __func__);
return NULL;
}
ctrla = ATC_SRC_WIDTH(dwidth) |
ATC_DST_WIDTH(dwidth);
ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN
| ATC_SRC_ADDR_MODE_INCR
| ATC_DST_ADDR_MODE_INCR
| ATC_SRC_PIP
| ATC_DST_PIP
| ATC_FC_MEM2MEM;
/* create the transfer */
desc = atc_desc_get(atchan);
if (!desc) {
dev_err(chan2dev(chan),
"%s: couldn't allocate our descriptor\n", __func__);
return NULL;
}
desc->lli.saddr = xt->src_start;
desc->lli.daddr = xt->dst_start;
desc->lli.ctrla = ctrla | xfer_count;
desc->lli.ctrlb = ctrlb;
desc->boundary = first->size >> dwidth;
desc->dst_hole = (dmaengine_get_dst_icg(xt, first) >> dwidth) + 1;
desc->src_hole = (dmaengine_get_src_icg(xt, first) >> dwidth) + 1;
desc->txd.cookie = -EBUSY;
desc->total_len = desc->len = len;
/* set end-of-link to the last link descriptor of list*/
set_desc_eol(desc);
desc->txd.flags = flags; /* client is in control of this ack */
return &desc->txd;
}
/**
* atc_prep_dma_memcpy - prepare a memcpy operation
* @chan: the channel to prepare operation on
* @dest: operation virtual destination address
* @src: operation virtual source address
* @len: operation length
* @flags: tx descriptor status flags
*/
static struct dma_async_tx_descriptor *
atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
size_t len, unsigned long flags)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_desc *desc = NULL;
struct at_desc *first = NULL;
struct at_desc *prev = NULL;
size_t xfer_count;
size_t offset;
unsigned int src_width;
unsigned int dst_width;
u32 ctrla;
u32 ctrlb;
dev_vdbg(chan2dev(chan), "prep_dma_memcpy: d%pad s%pad l0x%zx f0x%lx\n",
&dest, &src, len, flags);
if (unlikely(!len)) {
dev_dbg(chan2dev(chan), "prep_dma_memcpy: length is zero!\n");
return NULL;
}
ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN
| ATC_SRC_ADDR_MODE_INCR
| ATC_DST_ADDR_MODE_INCR
| ATC_FC_MEM2MEM;
/*
* We can be a lot more clever here, but this should take care
* of the most common optimization.
*/
src_width = dst_width = atc_get_xfer_width(src, dest, len);
ctrla = ATC_SRC_WIDTH(src_width) |
ATC_DST_WIDTH(dst_width);
for (offset = 0; offset < len; offset += xfer_count << src_width) {
xfer_count = min_t(size_t, (len - offset) >> src_width,
ATC_BTSIZE_MAX);
desc = atc_desc_get(atchan);
if (!desc)
goto err_desc_get;
desc->lli.saddr = src + offset;
desc->lli.daddr = dest + offset;
desc->lli.ctrla = ctrla | xfer_count;
desc->lli.ctrlb = ctrlb;
desc->txd.cookie = 0;
desc->len = xfer_count << src_width;
atc_desc_chain(&first, &prev, desc);
}
/* First descriptor of the chain embedds additional information */
first->txd.cookie = -EBUSY;
first->total_len = len;
/* set end-of-link to the last link descriptor of list*/
set_desc_eol(desc);
first->txd.flags = flags; /* client is in control of this ack */
return &first->txd;
err_desc_get:
atc_desc_put(atchan, first);
return NULL;
}
static struct at_desc *atc_create_memset_desc(struct dma_chan *chan,
dma_addr_t psrc,
dma_addr_t pdst,
size_t len)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_desc *desc;
size_t xfer_count;
u32 ctrla = ATC_SRC_WIDTH(2) | ATC_DST_WIDTH(2);
u32 ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN |
ATC_SRC_ADDR_MODE_FIXED |
ATC_DST_ADDR_MODE_INCR |
ATC_FC_MEM2MEM;
xfer_count = len >> 2;
if (xfer_count > ATC_BTSIZE_MAX) {
dev_err(chan2dev(chan), "%s: buffer is too big\n",
__func__);
return NULL;
}
desc = atc_desc_get(atchan);
if (!desc) {
dev_err(chan2dev(chan), "%s: can't get a descriptor\n",
__func__);
return NULL;
}
desc->lli.saddr = psrc;
desc->lli.daddr = pdst;
desc->lli.ctrla = ctrla | xfer_count;
desc->lli.ctrlb = ctrlb;
desc->txd.cookie = 0;
desc->len = len;
return desc;
}
/**
* atc_prep_dma_memset - prepare a memcpy operation
* @chan: the channel to prepare operation on
* @dest: operation virtual destination address
* @value: value to set memory buffer to
* @len: operation length
* @flags: tx descriptor status flags
*/
static struct dma_async_tx_descriptor *
atc_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
size_t len, unsigned long flags)
{
struct at_dma *atdma = to_at_dma(chan->device);
struct at_desc *desc;
void __iomem *vaddr;
dma_addr_t paddr;
dev_vdbg(chan2dev(chan), "%s: d%pad v0x%x l0x%zx f0x%lx\n", __func__,
&dest, value, len, flags);
if (unlikely(!len)) {
dev_dbg(chan2dev(chan), "%s: length is zero!\n", __func__);
return NULL;
}
if (!is_dma_fill_aligned(chan->device, dest, 0, len)) {
dev_dbg(chan2dev(chan), "%s: buffer is not aligned\n",
__func__);
return NULL;
}
vaddr = dma_pool_alloc(atdma->memset_pool, GFP_ATOMIC, &paddr);
if (!vaddr) {
dev_err(chan2dev(chan), "%s: couldn't allocate buffer\n",
__func__);
return NULL;
}
*(u32*)vaddr = value;
desc = atc_create_memset_desc(chan, paddr, dest, len);
if (!desc) {
dev_err(chan2dev(chan), "%s: couldn't get a descriptor\n",
__func__);
goto err_free_buffer;
}
desc->memset_paddr = paddr;
desc->memset_vaddr = vaddr;
desc->memset_buffer = true;
desc->txd.cookie = -EBUSY;
desc->total_len = len;
/* set end-of-link on the descriptor */
set_desc_eol(desc);
desc->txd.flags = flags;
return &desc->txd;
err_free_buffer:
dma_pool_free(atdma->memset_pool, vaddr, paddr);
return NULL;
}
static struct dma_async_tx_descriptor *
atc_prep_dma_memset_sg(struct dma_chan *chan,
struct scatterlist *sgl,
unsigned int sg_len, int value,
unsigned long flags)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_dma *atdma = to_at_dma(chan->device);
struct at_desc *desc = NULL, *first = NULL, *prev = NULL;
struct scatterlist *sg;
void __iomem *vaddr;
dma_addr_t paddr;
size_t total_len = 0;
int i;
dev_vdbg(chan2dev(chan), "%s: v0x%x l0x%zx f0x%lx\n", __func__,
value, sg_len, flags);
if (unlikely(!sgl || !sg_len)) {