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linux-sg2042/drivers/dma/sh/rcar-dmac.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Renesas R-Car Gen2/Gen3 DMA Controller Driver
*
* Copyright (C) 2014-2019 Renesas Electronics Inc.
*
* Author: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
*/
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_dma.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include "../dmaengine.h"
/*
* struct rcar_dmac_xfer_chunk - Descriptor for a hardware transfer
* @node: entry in the parent's chunks list
* @src_addr: device source address
* @dst_addr: device destination address
* @size: transfer size in bytes
*/
struct rcar_dmac_xfer_chunk {
struct list_head node;
dma_addr_t src_addr;
dma_addr_t dst_addr;
u32 size;
};
/*
* struct rcar_dmac_hw_desc - Hardware descriptor for a transfer chunk
* @sar: value of the SAR register (source address)
* @dar: value of the DAR register (destination address)
* @tcr: value of the TCR register (transfer count)
*/
struct rcar_dmac_hw_desc {
u32 sar;
u32 dar;
u32 tcr;
u32 reserved;
} __attribute__((__packed__));
/*
* struct rcar_dmac_desc - R-Car Gen2 DMA Transfer Descriptor
* @async_tx: base DMA asynchronous transaction descriptor
* @direction: direction of the DMA transfer
* @xfer_shift: log2 of the transfer size
* @chcr: value of the channel configuration register for this transfer
* @node: entry in the channel's descriptors lists
* @chunks: list of transfer chunks for this transfer
* @running: the transfer chunk being currently processed
* @nchunks: number of transfer chunks for this transfer
* @hwdescs.use: whether the transfer descriptor uses hardware descriptors
* @hwdescs.mem: hardware descriptors memory for the transfer
* @hwdescs.dma: device address of the hardware descriptors memory
* @hwdescs.size: size of the hardware descriptors in bytes
* @size: transfer size in bytes
* @cyclic: when set indicates that the DMA transfer is cyclic
*/
struct rcar_dmac_desc {
struct dma_async_tx_descriptor async_tx;
enum dma_transfer_direction direction;
unsigned int xfer_shift;
u32 chcr;
struct list_head node;
struct list_head chunks;
struct rcar_dmac_xfer_chunk *running;
unsigned int nchunks;
struct {
bool use;
struct rcar_dmac_hw_desc *mem;
dma_addr_t dma;
size_t size;
} hwdescs;
unsigned int size;
bool cyclic;
};
#define to_rcar_dmac_desc(d) container_of(d, struct rcar_dmac_desc, async_tx)
/*
* struct rcar_dmac_desc_page - One page worth of descriptors
* @node: entry in the channel's pages list
* @descs: array of DMA descriptors
* @chunks: array of transfer chunk descriptors
*/
struct rcar_dmac_desc_page {
struct list_head node;
union {
struct rcar_dmac_desc descs[0];
struct rcar_dmac_xfer_chunk chunks[0];
};
};
#define RCAR_DMAC_DESCS_PER_PAGE \
((PAGE_SIZE - offsetof(struct rcar_dmac_desc_page, descs)) / \
sizeof(struct rcar_dmac_desc))
#define RCAR_DMAC_XFER_CHUNKS_PER_PAGE \
((PAGE_SIZE - offsetof(struct rcar_dmac_desc_page, chunks)) / \
sizeof(struct rcar_dmac_xfer_chunk))
/*
* struct rcar_dmac_chan_slave - Slave configuration
* @slave_addr: slave memory address
* @xfer_size: size (in bytes) of hardware transfers
*/
struct rcar_dmac_chan_slave {
phys_addr_t slave_addr;
unsigned int xfer_size;
};
/*
* struct rcar_dmac_chan_map - Map of slave device phys to dma address
* @addr: slave dma address
* @dir: direction of mapping
* @slave: slave configuration that is mapped
*/
struct rcar_dmac_chan_map {
dma_addr_t addr;
enum dma_data_direction dir;
struct rcar_dmac_chan_slave slave;
};
/*
* struct rcar_dmac_chan - R-Car Gen2 DMA Controller Channel
* @chan: base DMA channel object
* @iomem: channel I/O memory base
* @index: index of this channel in the controller
* @irq: channel IRQ
* @src: slave memory address and size on the source side
* @dst: slave memory address and size on the destination side
* @mid_rid: hardware MID/RID for the DMA client using this channel
* @lock: protects the channel CHCR register and the desc members
* @desc.free: list of free descriptors
* @desc.pending: list of pending descriptors (submitted with tx_submit)
* @desc.active: list of active descriptors (activated with issue_pending)
* @desc.done: list of completed descriptors
* @desc.wait: list of descriptors waiting for an ack
* @desc.running: the descriptor being processed (a member of the active list)
* @desc.chunks_free: list of free transfer chunk descriptors
* @desc.pages: list of pages used by allocated descriptors
*/
struct rcar_dmac_chan {
struct dma_chan chan;
void __iomem *iomem;
unsigned int index;
int irq;
struct rcar_dmac_chan_slave src;
struct rcar_dmac_chan_slave dst;
struct rcar_dmac_chan_map map;
int mid_rid;
spinlock_t lock;
struct {
struct list_head free;
struct list_head pending;
struct list_head active;
struct list_head done;
struct list_head wait;
struct rcar_dmac_desc *running;
struct list_head chunks_free;
struct list_head pages;
} desc;
};
#define to_rcar_dmac_chan(c) container_of(c, struct rcar_dmac_chan, chan)
/*
* struct rcar_dmac - R-Car Gen2 DMA Controller
* @engine: base DMA engine object
* @dev: the hardware device
* @dmac_base: remapped base register block
* @chan_base: remapped channel register block (optional)
* @n_channels: number of available channels
* @channels: array of DMAC channels
* @channels_mask: bitfield of which DMA channels are managed by this driver
* @modules: bitmask of client modules in use
*/
struct rcar_dmac {
struct dma_device engine;
struct device *dev;
void __iomem *dmac_base;
void __iomem *chan_base;
unsigned int n_channels;
struct rcar_dmac_chan *channels;
u32 channels_mask;
DECLARE_BITMAP(modules, 256);
};
#define to_rcar_dmac(d) container_of(d, struct rcar_dmac, engine)
#define for_each_rcar_dmac_chan(i, dmac, chan) \
for (i = 0, chan = &(dmac)->channels[0]; i < (dmac)->n_channels; i++, chan++) \
if (!((dmac)->channels_mask & BIT(i))) continue; else
/*
* struct rcar_dmac_of_data - This driver's OF data
* @chan_offset_base: DMAC channels base offset
* @chan_offset_stride: DMAC channels offset stride
*/
struct rcar_dmac_of_data {
u32 chan_offset_base;
u32 chan_offset_stride;
};
/* -----------------------------------------------------------------------------
* Registers
*/
#define RCAR_DMAISTA 0x0020
#define RCAR_DMASEC 0x0030
#define RCAR_DMAOR 0x0060
#define RCAR_DMAOR_PRI_FIXED (0 << 8)
#define RCAR_DMAOR_PRI_ROUND_ROBIN (3 << 8)
#define RCAR_DMAOR_AE (1 << 2)
#define RCAR_DMAOR_DME (1 << 0)
#define RCAR_DMACHCLR 0x0080 /* Not on R-Car V3U */
#define RCAR_DMADPSEC 0x00a0
#define RCAR_DMASAR 0x0000
#define RCAR_DMADAR 0x0004
#define RCAR_DMATCR 0x0008
#define RCAR_DMATCR_MASK 0x00ffffff
#define RCAR_DMATSR 0x0028
#define RCAR_DMACHCR 0x000c
#define RCAR_DMACHCR_CAE (1 << 31)
#define RCAR_DMACHCR_CAIE (1 << 30)
#define RCAR_DMACHCR_DPM_DISABLED (0 << 28)
#define RCAR_DMACHCR_DPM_ENABLED (1 << 28)
#define RCAR_DMACHCR_DPM_REPEAT (2 << 28)
#define RCAR_DMACHCR_DPM_INFINITE (3 << 28)
#define RCAR_DMACHCR_RPT_SAR (1 << 27)
#define RCAR_DMACHCR_RPT_DAR (1 << 26)
#define RCAR_DMACHCR_RPT_TCR (1 << 25)
#define RCAR_DMACHCR_DPB (1 << 22)
#define RCAR_DMACHCR_DSE (1 << 19)
#define RCAR_DMACHCR_DSIE (1 << 18)
#define RCAR_DMACHCR_TS_1B ((0 << 20) | (0 << 3))
#define RCAR_DMACHCR_TS_2B ((0 << 20) | (1 << 3))
#define RCAR_DMACHCR_TS_4B ((0 << 20) | (2 << 3))
#define RCAR_DMACHCR_TS_16B ((0 << 20) | (3 << 3))
#define RCAR_DMACHCR_TS_32B ((1 << 20) | (0 << 3))
#define RCAR_DMACHCR_TS_64B ((1 << 20) | (1 << 3))
#define RCAR_DMACHCR_TS_8B ((1 << 20) | (3 << 3))
#define RCAR_DMACHCR_DM_FIXED (0 << 14)
#define RCAR_DMACHCR_DM_INC (1 << 14)
#define RCAR_DMACHCR_DM_DEC (2 << 14)
#define RCAR_DMACHCR_SM_FIXED (0 << 12)
#define RCAR_DMACHCR_SM_INC (1 << 12)
#define RCAR_DMACHCR_SM_DEC (2 << 12)
#define RCAR_DMACHCR_RS_AUTO (4 << 8)
#define RCAR_DMACHCR_RS_DMARS (8 << 8)
#define RCAR_DMACHCR_IE (1 << 2)
#define RCAR_DMACHCR_TE (1 << 1)
#define RCAR_DMACHCR_DE (1 << 0)
#define RCAR_DMATCRB 0x0018
#define RCAR_DMATSRB 0x0038
#define RCAR_DMACHCRB 0x001c
#define RCAR_DMACHCRB_DCNT(n) ((n) << 24)
#define RCAR_DMACHCRB_DPTR_MASK (0xff << 16)
#define RCAR_DMACHCRB_DPTR_SHIFT 16
#define RCAR_DMACHCRB_DRST (1 << 15)
#define RCAR_DMACHCRB_DTS (1 << 8)
#define RCAR_DMACHCRB_SLM_NORMAL (0 << 4)
#define RCAR_DMACHCRB_SLM_CLK(n) ((8 | (n)) << 4)
#define RCAR_DMACHCRB_PRI(n) ((n) << 0)
#define RCAR_DMARS 0x0040
#define RCAR_DMABUFCR 0x0048
#define RCAR_DMABUFCR_MBU(n) ((n) << 16)
#define RCAR_DMABUFCR_ULB(n) ((n) << 0)
#define RCAR_DMADPBASE 0x0050
#define RCAR_DMADPBASE_MASK 0xfffffff0
#define RCAR_DMADPBASE_SEL (1 << 0)
#define RCAR_DMADPCR 0x0054
#define RCAR_DMADPCR_DIPT(n) ((n) << 24)
#define RCAR_DMAFIXSAR 0x0010
#define RCAR_DMAFIXDAR 0x0014
#define RCAR_DMAFIXDPBASE 0x0060
/* For R-Car V3U */
#define RCAR_V3U_DMACHCLR 0x0100
/* Hardcode the MEMCPY transfer size to 4 bytes. */
#define RCAR_DMAC_MEMCPY_XFER_SIZE 4
/* -----------------------------------------------------------------------------
* Device access
*/
static void rcar_dmac_write(struct rcar_dmac *dmac, u32 reg, u32 data)
{
if (reg == RCAR_DMAOR)
writew(data, dmac->dmac_base + reg);
else
writel(data, dmac->dmac_base + reg);
}
static u32 rcar_dmac_read(struct rcar_dmac *dmac, u32 reg)
{
if (reg == RCAR_DMAOR)
return readw(dmac->dmac_base + reg);
else
return readl(dmac->dmac_base + reg);
}
static u32 rcar_dmac_chan_read(struct rcar_dmac_chan *chan, u32 reg)
{
if (reg == RCAR_DMARS)
return readw(chan->iomem + reg);
else
return readl(chan->iomem + reg);
}
static void rcar_dmac_chan_write(struct rcar_dmac_chan *chan, u32 reg, u32 data)
{
if (reg == RCAR_DMARS)
writew(data, chan->iomem + reg);
else
writel(data, chan->iomem + reg);
}
static void rcar_dmac_chan_clear(struct rcar_dmac *dmac,
struct rcar_dmac_chan *chan)
{
if (dmac->chan_base)
rcar_dmac_chan_write(chan, RCAR_V3U_DMACHCLR, 1);
else
rcar_dmac_write(dmac, RCAR_DMACHCLR, BIT(chan->index));
}
static void rcar_dmac_chan_clear_all(struct rcar_dmac *dmac)
{
struct rcar_dmac_chan *chan;
unsigned int i;
if (dmac->chan_base) {
for_each_rcar_dmac_chan(i, dmac, chan)
rcar_dmac_chan_write(chan, RCAR_V3U_DMACHCLR, 1);
} else {
rcar_dmac_write(dmac, RCAR_DMACHCLR, dmac->channels_mask);
}
}
/* -----------------------------------------------------------------------------
* Initialization and configuration
*/
static bool rcar_dmac_chan_is_busy(struct rcar_dmac_chan *chan)
{
u32 chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
return !!(chcr & (RCAR_DMACHCR_DE | RCAR_DMACHCR_TE));
}
static void rcar_dmac_chan_start_xfer(struct rcar_dmac_chan *chan)
{
struct rcar_dmac_desc *desc = chan->desc.running;
u32 chcr = desc->chcr;
WARN_ON_ONCE(rcar_dmac_chan_is_busy(chan));
if (chan->mid_rid >= 0)
rcar_dmac_chan_write(chan, RCAR_DMARS, chan->mid_rid);
if (desc->hwdescs.use) {
struct rcar_dmac_xfer_chunk *chunk =
list_first_entry(&desc->chunks,
struct rcar_dmac_xfer_chunk, node);
dev_dbg(chan->chan.device->dev,
"chan%u: queue desc %p: %u@%pad\n",
chan->index, desc, desc->nchunks, &desc->hwdescs.dma);
#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
rcar_dmac_chan_write(chan, RCAR_DMAFIXSAR,
chunk->src_addr >> 32);
rcar_dmac_chan_write(chan, RCAR_DMAFIXDAR,
chunk->dst_addr >> 32);
rcar_dmac_chan_write(chan, RCAR_DMAFIXDPBASE,
desc->hwdescs.dma >> 32);
#endif
rcar_dmac_chan_write(chan, RCAR_DMADPBASE,
(desc->hwdescs.dma & 0xfffffff0) |
RCAR_DMADPBASE_SEL);
rcar_dmac_chan_write(chan, RCAR_DMACHCRB,
RCAR_DMACHCRB_DCNT(desc->nchunks - 1) |
RCAR_DMACHCRB_DRST);
/*
* Errata: When descriptor memory is accessed through an IOMMU
* the DMADAR register isn't initialized automatically from the
* first descriptor at beginning of transfer by the DMAC like it
* should. Initialize it manually with the destination address
* of the first chunk.
*/
rcar_dmac_chan_write(chan, RCAR_DMADAR,
chunk->dst_addr & 0xffffffff);
/*
* Program the descriptor stage interrupt to occur after the end
* of the first stage.
*/
rcar_dmac_chan_write(chan, RCAR_DMADPCR, RCAR_DMADPCR_DIPT(1));
chcr |= RCAR_DMACHCR_RPT_SAR | RCAR_DMACHCR_RPT_DAR
| RCAR_DMACHCR_RPT_TCR | RCAR_DMACHCR_DPB;
/*
* If the descriptor isn't cyclic enable normal descriptor mode
* and the transfer completion interrupt.
*/
if (!desc->cyclic)
chcr |= RCAR_DMACHCR_DPM_ENABLED | RCAR_DMACHCR_IE;
/*
* If the descriptor is cyclic and has a callback enable the
* descriptor stage interrupt in infinite repeat mode.
*/
else if (desc->async_tx.callback)
chcr |= RCAR_DMACHCR_DPM_INFINITE | RCAR_DMACHCR_DSIE;
/*
* Otherwise just select infinite repeat mode without any
* interrupt.
*/
else
chcr |= RCAR_DMACHCR_DPM_INFINITE;
} else {
struct rcar_dmac_xfer_chunk *chunk = desc->running;
dev_dbg(chan->chan.device->dev,
"chan%u: queue chunk %p: %u@%pad -> %pad\n",
chan->index, chunk, chunk->size, &chunk->src_addr,
&chunk->dst_addr);
#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
rcar_dmac_chan_write(chan, RCAR_DMAFIXSAR,
chunk->src_addr >> 32);
rcar_dmac_chan_write(chan, RCAR_DMAFIXDAR,
chunk->dst_addr >> 32);
#endif
rcar_dmac_chan_write(chan, RCAR_DMASAR,
chunk->src_addr & 0xffffffff);
rcar_dmac_chan_write(chan, RCAR_DMADAR,
chunk->dst_addr & 0xffffffff);
rcar_dmac_chan_write(chan, RCAR_DMATCR,
chunk->size >> desc->xfer_shift);
chcr |= RCAR_DMACHCR_DPM_DISABLED | RCAR_DMACHCR_IE;
}
rcar_dmac_chan_write(chan, RCAR_DMACHCR,
chcr | RCAR_DMACHCR_DE | RCAR_DMACHCR_CAIE);
}
static int rcar_dmac_init(struct rcar_dmac *dmac)
{
u16 dmaor;
/* Clear all channels and enable the DMAC globally. */
rcar_dmac_chan_clear_all(dmac);
rcar_dmac_write(dmac, RCAR_DMAOR,
RCAR_DMAOR_PRI_FIXED | RCAR_DMAOR_DME);
dmaor = rcar_dmac_read(dmac, RCAR_DMAOR);
if ((dmaor & (RCAR_DMAOR_AE | RCAR_DMAOR_DME)) != RCAR_DMAOR_DME) {
dev_warn(dmac->dev, "DMAOR initialization failed.\n");
return -EIO;
}
return 0;
}
/* -----------------------------------------------------------------------------
* Descriptors submission
*/
static dma_cookie_t rcar_dmac_tx_submit(struct dma_async_tx_descriptor *tx)
{
struct rcar_dmac_chan *chan = to_rcar_dmac_chan(tx->chan);
struct rcar_dmac_desc *desc = to_rcar_dmac_desc(tx);
unsigned long flags;
dma_cookie_t cookie;
spin_lock_irqsave(&chan->lock, flags);
cookie = dma_cookie_assign(tx);
dev_dbg(chan->chan.device->dev, "chan%u: submit #%d@%p\n",
chan->index, tx->cookie, desc);
list_add_tail(&desc->node, &chan->desc.pending);
desc->running = list_first_entry(&desc->chunks,
struct rcar_dmac_xfer_chunk, node);
spin_unlock_irqrestore(&chan->lock, flags);
return cookie;
}
/* -----------------------------------------------------------------------------
* Descriptors allocation and free
*/
/*
* rcar_dmac_desc_alloc - Allocate a page worth of DMA descriptors
* @chan: the DMA channel
* @gfp: allocation flags
*/
static int rcar_dmac_desc_alloc(struct rcar_dmac_chan *chan, gfp_t gfp)
{
struct rcar_dmac_desc_page *page;
unsigned long flags;
LIST_HEAD(list);
unsigned int i;
page = (void *)get_zeroed_page(gfp);
if (!page)
return -ENOMEM;
for (i = 0; i < RCAR_DMAC_DESCS_PER_PAGE; ++i) {
struct rcar_dmac_desc *desc = &page->descs[i];
dma_async_tx_descriptor_init(&desc->async_tx, &chan->chan);
desc->async_tx.tx_submit = rcar_dmac_tx_submit;
INIT_LIST_HEAD(&desc->chunks);
list_add_tail(&desc->node, &list);
}
spin_lock_irqsave(&chan->lock, flags);
list_splice_tail(&list, &chan->desc.free);
list_add_tail(&page->node, &chan->desc.pages);
spin_unlock_irqrestore(&chan->lock, flags);
return 0;
}
/*
* rcar_dmac_desc_put - Release a DMA transfer descriptor
* @chan: the DMA channel
* @desc: the descriptor
*
* Put the descriptor and its transfer chunk descriptors back in the channel's
* free descriptors lists. The descriptor's chunks list will be reinitialized to
* an empty list as a result.
*
* The descriptor must have been removed from the channel's lists before calling
* this function.
*/
static void rcar_dmac_desc_put(struct rcar_dmac_chan *chan,
struct rcar_dmac_desc *desc)
{
unsigned long flags;
spin_lock_irqsave(&chan->lock, flags);
list_splice_tail_init(&desc->chunks, &chan->desc.chunks_free);
list_add(&desc->node, &chan->desc.free);
spin_unlock_irqrestore(&chan->lock, flags);
}
static void rcar_dmac_desc_recycle_acked(struct rcar_dmac_chan *chan)
{
struct rcar_dmac_desc *desc, *_desc;
unsigned long flags;
LIST_HEAD(list);
/*
* We have to temporarily move all descriptors from the wait list to a
* local list as iterating over the wait list, even with
* list_for_each_entry_safe, isn't safe if we release the channel lock
* around the rcar_dmac_desc_put() call.
*/
spin_lock_irqsave(&chan->lock, flags);
list_splice_init(&chan->desc.wait, &list);
spin_unlock_irqrestore(&chan->lock, flags);
list_for_each_entry_safe(desc, _desc, &list, node) {
if (async_tx_test_ack(&desc->async_tx)) {
list_del(&desc->node);
rcar_dmac_desc_put(chan, desc);
}
}
if (list_empty(&list))
return;
/* Put the remaining descriptors back in the wait list. */
spin_lock_irqsave(&chan->lock, flags);
list_splice(&list, &chan->desc.wait);
spin_unlock_irqrestore(&chan->lock, flags);
}
/*
* rcar_dmac_desc_get - Allocate a descriptor for a DMA transfer
* @chan: the DMA channel
*
* Locking: This function must be called in a non-atomic context.
*
* Return: A pointer to the allocated descriptor or NULL if no descriptor can
* be allocated.
*/
static struct rcar_dmac_desc *rcar_dmac_desc_get(struct rcar_dmac_chan *chan)
{
struct rcar_dmac_desc *desc;
unsigned long flags;
int ret;
/* Recycle acked descriptors before attempting allocation. */
rcar_dmac_desc_recycle_acked(chan);
spin_lock_irqsave(&chan->lock, flags);
while (list_empty(&chan->desc.free)) {
/*
* No free descriptors, allocate a page worth of them and try
* again, as someone else could race us to get the newly
* allocated descriptors. If the allocation fails return an
* error.
*/
spin_unlock_irqrestore(&chan->lock, flags);
ret = rcar_dmac_desc_alloc(chan, GFP_NOWAIT);
if (ret < 0)
return NULL;
spin_lock_irqsave(&chan->lock, flags);
}
desc = list_first_entry(&chan->desc.free, struct rcar_dmac_desc, node);
list_del(&desc->node);
spin_unlock_irqrestore(&chan->lock, flags);
return desc;
}
/*
* rcar_dmac_xfer_chunk_alloc - Allocate a page worth of transfer chunks
* @chan: the DMA channel
* @gfp: allocation flags
*/
static int rcar_dmac_xfer_chunk_alloc(struct rcar_dmac_chan *chan, gfp_t gfp)
{
struct rcar_dmac_desc_page *page;
unsigned long flags;
LIST_HEAD(list);
unsigned int i;
page = (void *)get_zeroed_page(gfp);
if (!page)
return -ENOMEM;
for (i = 0; i < RCAR_DMAC_XFER_CHUNKS_PER_PAGE; ++i) {
struct rcar_dmac_xfer_chunk *chunk = &page->chunks[i];
list_add_tail(&chunk->node, &list);
}
spin_lock_irqsave(&chan->lock, flags);
list_splice_tail(&list, &chan->desc.chunks_free);
list_add_tail(&page->node, &chan->desc.pages);
spin_unlock_irqrestore(&chan->lock, flags);
return 0;
}
/*
* rcar_dmac_xfer_chunk_get - Allocate a transfer chunk for a DMA transfer
* @chan: the DMA channel
*
* Locking: This function must be called in a non-atomic context.
*
* Return: A pointer to the allocated transfer chunk descriptor or NULL if no
* descriptor can be allocated.
*/
static struct rcar_dmac_xfer_chunk *
rcar_dmac_xfer_chunk_get(struct rcar_dmac_chan *chan)
{
struct rcar_dmac_xfer_chunk *chunk;
unsigned long flags;
int ret;
spin_lock_irqsave(&chan->lock, flags);
while (list_empty(&chan->desc.chunks_free)) {
/*
* No free descriptors, allocate a page worth of them and try
* again, as someone else could race us to get the newly
* allocated descriptors. If the allocation fails return an
* error.
*/
spin_unlock_irqrestore(&chan->lock, flags);
ret = rcar_dmac_xfer_chunk_alloc(chan, GFP_NOWAIT);
if (ret < 0)
return NULL;
spin_lock_irqsave(&chan->lock, flags);
}
chunk = list_first_entry(&chan->desc.chunks_free,
struct rcar_dmac_xfer_chunk, node);
list_del(&chunk->node);
spin_unlock_irqrestore(&chan->lock, flags);
return chunk;
}
static void rcar_dmac_realloc_hwdesc(struct rcar_dmac_chan *chan,
struct rcar_dmac_desc *desc, size_t size)
{
/*
* dma_alloc_coherent() allocates memory in page size increments. To
* avoid reallocating the hardware descriptors when the allocated size
* wouldn't change align the requested size to a multiple of the page
* size.
*/
size = PAGE_ALIGN(size);
if (desc->hwdescs.size == size)
return;
if (desc->hwdescs.mem) {
dma_free_coherent(chan->chan.device->dev, desc->hwdescs.size,
desc->hwdescs.mem, desc->hwdescs.dma);
desc->hwdescs.mem = NULL;
desc->hwdescs.size = 0;
}
if (!size)
return;
desc->hwdescs.mem = dma_alloc_coherent(chan->chan.device->dev, size,
&desc->hwdescs.dma, GFP_NOWAIT);
if (!desc->hwdescs.mem)
return;
desc->hwdescs.size = size;
}
static int rcar_dmac_fill_hwdesc(struct rcar_dmac_chan *chan,
struct rcar_dmac_desc *desc)
{
struct rcar_dmac_xfer_chunk *chunk;
struct rcar_dmac_hw_desc *hwdesc;
rcar_dmac_realloc_hwdesc(chan, desc, desc->nchunks * sizeof(*hwdesc));
hwdesc = desc->hwdescs.mem;
if (!hwdesc)
return -ENOMEM;
list_for_each_entry(chunk, &desc->chunks, node) {
hwdesc->sar = chunk->src_addr;
hwdesc->dar = chunk->dst_addr;
hwdesc->tcr = chunk->size >> desc->xfer_shift;
hwdesc++;
}
return 0;
}
/* -----------------------------------------------------------------------------
* Stop and reset
*/
static void rcar_dmac_chcr_de_barrier(struct rcar_dmac_chan *chan)
{
u32 chcr;
unsigned int i;
/*
* Ensure that the setting of the DE bit is actually 0 after
* clearing it.
*/
for (i = 0; i < 1024; i++) {
chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
if (!(chcr & RCAR_DMACHCR_DE))
return;
udelay(1);
}
dev_err(chan->chan.device->dev, "CHCR DE check error\n");
}
static void rcar_dmac_clear_chcr_de(struct rcar_dmac_chan *chan)
{
u32 chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
/* set DE=0 and flush remaining data */
rcar_dmac_chan_write(chan, RCAR_DMACHCR, (chcr & ~RCAR_DMACHCR_DE));
/* make sure all remaining data was flushed */
rcar_dmac_chcr_de_barrier(chan);
}
static void rcar_dmac_chan_halt(struct rcar_dmac_chan *chan)
{
u32 chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
chcr &= ~(RCAR_DMACHCR_DSE | RCAR_DMACHCR_DSIE | RCAR_DMACHCR_IE |
RCAR_DMACHCR_TE | RCAR_DMACHCR_DE |
RCAR_DMACHCR_CAE | RCAR_DMACHCR_CAIE);
rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr);
rcar_dmac_chcr_de_barrier(chan);
}
static void rcar_dmac_chan_reinit(struct rcar_dmac_chan *chan)
{
struct rcar_dmac_desc *desc, *_desc;
unsigned long flags;
LIST_HEAD(descs);
spin_lock_irqsave(&chan->lock, flags);
/* Move all non-free descriptors to the local lists. */
list_splice_init(&chan->desc.pending, &descs);
list_splice_init(&chan->desc.active, &descs);
list_splice_init(&chan->desc.done, &descs);
list_splice_init(&chan->desc.wait, &descs);
chan->desc.running = NULL;
spin_unlock_irqrestore(&chan->lock, flags);
list_for_each_entry_safe(desc, _desc, &descs, node) {
list_del(&desc->node);
rcar_dmac_desc_put(chan, desc);
}
}
static void rcar_dmac_stop_all_chan(struct rcar_dmac *dmac)
{
struct rcar_dmac_chan *chan;
unsigned int i;
/* Stop all channels. */
for_each_rcar_dmac_chan(i, dmac, chan) {
/* Stop and reinitialize the channel. */
spin_lock_irq(&chan->lock);
rcar_dmac_chan_halt(chan);
spin_unlock_irq(&chan->lock);
}
}
static int rcar_dmac_chan_pause(struct dma_chan *chan)
{
unsigned long flags;
struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
spin_lock_irqsave(&rchan->lock, flags);
rcar_dmac_clear_chcr_de(rchan);
spin_unlock_irqrestore(&rchan->lock, flags);
return 0;
}
/* -----------------------------------------------------------------------------
* Descriptors preparation
*/
static void rcar_dmac_chan_configure_desc(struct rcar_dmac_chan *chan,
struct rcar_dmac_desc *desc)
{
static const u32 chcr_ts[] = {
RCAR_DMACHCR_TS_1B, RCAR_DMACHCR_TS_2B,
RCAR_DMACHCR_TS_4B, RCAR_DMACHCR_TS_8B,
RCAR_DMACHCR_TS_16B, RCAR_DMACHCR_TS_32B,
RCAR_DMACHCR_TS_64B,
};
unsigned int xfer_size;
u32 chcr;
switch (desc->direction) {
case DMA_DEV_TO_MEM:
chcr = RCAR_DMACHCR_DM_INC | RCAR_DMACHCR_SM_FIXED
| RCAR_DMACHCR_RS_DMARS;
xfer_size = chan->src.xfer_size;
break;
case DMA_MEM_TO_DEV:
chcr = RCAR_DMACHCR_DM_FIXED | RCAR_DMACHCR_SM_INC
| RCAR_DMACHCR_RS_DMARS;
xfer_size = chan->dst.xfer_size;
break;
case DMA_MEM_TO_MEM:
default:
chcr = RCAR_DMACHCR_DM_INC | RCAR_DMACHCR_SM_INC
| RCAR_DMACHCR_RS_AUTO;
xfer_size = RCAR_DMAC_MEMCPY_XFER_SIZE;
break;
}
desc->xfer_shift = ilog2(xfer_size);
desc->chcr = chcr | chcr_ts[desc->xfer_shift];
}
/*
* rcar_dmac_chan_prep_sg - prepare transfer descriptors from an SG list
*
* Common routine for public (MEMCPY) and slave DMA. The MEMCPY case is also
* converted to scatter-gather to guarantee consistent locking and a correct
* list manipulation. For slave DMA direction carries the usual meaning, and,
* logically, the SG list is RAM and the addr variable contains slave address,
* e.g., the FIFO I/O register. For MEMCPY direction equals DMA_MEM_TO_MEM
* and the SG list contains only one element and points at the source buffer.
*/
static struct dma_async_tx_descriptor *
rcar_dmac_chan_prep_sg(struct rcar_dmac_chan *chan, struct scatterlist *sgl,
unsigned int sg_len, dma_addr_t dev_addr,
enum dma_transfer_direction dir, unsigned long dma_flags,
bool cyclic)
{
struct rcar_dmac_xfer_chunk *chunk;
struct rcar_dmac_desc *desc;
struct scatterlist *sg;
unsigned int nchunks = 0;
unsigned int max_chunk_size;
unsigned int full_size = 0;
bool cross_boundary = false;
unsigned int i;
#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
u32 high_dev_addr;
u32 high_mem_addr;
#endif
desc = rcar_dmac_desc_get(chan);
if (!desc)
return NULL;
desc->async_tx.flags = dma_flags;
desc->async_tx.cookie = -EBUSY;
desc->cyclic = cyclic;
desc->direction = dir;
rcar_dmac_chan_configure_desc(chan, desc);
max_chunk_size = RCAR_DMATCR_MASK << desc->xfer_shift;
/*
* Allocate and fill the transfer chunk descriptors. We own the only
* reference to the DMA descriptor, there's no need for locking.
*/
for_each_sg(sgl, sg, sg_len, i) {
dma_addr_t mem_addr = sg_dma_address(sg);
unsigned int len = sg_dma_len(sg);
full_size += len;
#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
if (i == 0) {
high_dev_addr = dev_addr >> 32;
high_mem_addr = mem_addr >> 32;
}
if ((dev_addr >> 32 != high_dev_addr) ||
(mem_addr >> 32 != high_mem_addr))
cross_boundary = true;
#endif
while (len) {
unsigned int size = min(len, max_chunk_size);
#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
/*
* Prevent individual transfers from crossing 4GB
* boundaries.
*/
if (dev_addr >> 32 != (dev_addr + size - 1) >> 32) {
size = ALIGN(dev_addr, 1ULL << 32) - dev_addr;
cross_boundary = true;
}
if (mem_addr >> 32 != (mem_addr + size - 1) >> 32) {
size = ALIGN(mem_addr, 1ULL << 32) - mem_addr;
cross_boundary = true;
}
#endif
chunk = rcar_dmac_xfer_chunk_get(chan);
if (!chunk) {
rcar_dmac_desc_put(chan, desc);
return NULL;
}
if (dir == DMA_DEV_TO_MEM) {
chunk->src_addr = dev_addr;
chunk->dst_addr = mem_addr;
} else {
chunk->src_addr = mem_addr;
chunk->dst_addr = dev_addr;
}
chunk->size = size;
dev_dbg(chan->chan.device->dev,
"chan%u: chunk %p/%p sgl %u@%p, %u/%u %pad -> %pad\n",
chan->index, chunk, desc, i, sg, size, len,
&chunk->src_addr, &chunk->dst_addr);
mem_addr += size;
if (dir == DMA_MEM_TO_MEM)
dev_addr += size;
len -= size;
list_add_tail(&chunk->node, &desc->chunks);
nchunks++;
}
}
desc->nchunks = nchunks;
desc->size = full_size;
/*
* Use hardware descriptor lists if possible when more than one chunk
* needs to be transferred (otherwise they don't make much sense).
*
* Source/Destination address should be located in same 4GiB region
* in the 40bit address space when it uses Hardware descriptor,
* and cross_boundary is checking it.
*/
desc->hwdescs.use = !cross_boundary && nchunks > 1;
if (desc->hwdescs.use) {
if (rcar_dmac_fill_hwdesc(chan, desc) < 0)
desc->hwdescs.use = false;
}
return &desc->async_tx;
}
/* -----------------------------------------------------------------------------
* DMA engine operations
*/
static int rcar_dmac_alloc_chan_resources(struct dma_chan *chan)
{
struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
int ret;
INIT_LIST_HEAD(&rchan->desc.chunks_free);
INIT_LIST_HEAD(&rchan->desc.pages);
/* Preallocate descriptors. */
ret = rcar_dmac_xfer_chunk_alloc(rchan, GFP_KERNEL);
if (ret < 0)
return -ENOMEM;
ret = rcar_dmac_desc_alloc(rchan, GFP_KERNEL);
if (ret < 0)
return -ENOMEM;
return pm_runtime_get_sync(chan->device->dev);
}
static void rcar_dmac_free_chan_resources(struct dma_chan *chan)
{
struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
struct rcar_dmac *dmac = to_rcar_dmac(chan->device);
struct rcar_dmac_chan_map *map = &rchan->map;
struct rcar_dmac_desc_page *page, *_page;
struct rcar_dmac_desc *desc;
LIST_HEAD(list);
/* Protect against ISR */
spin_lock_irq(&rchan->lock);
rcar_dmac_chan_halt(rchan);
spin_unlock_irq(&rchan->lock);
/*
* Now no new interrupts will occur, but one might already be
* running. Wait for it to finish before freeing resources.
*/
synchronize_irq(rchan->irq);
if (rchan->mid_rid >= 0) {
/* The caller is holding dma_list_mutex */
clear_bit(rchan->mid_rid, dmac->modules);
rchan->mid_rid = -EINVAL;
}
list_splice_init(&rchan->desc.free, &list);
list_splice_init(&rchan->desc.pending, &list);
list_splice_init(&rchan->desc.active, &list);
list_splice_init(&rchan->desc.done, &list);
list_splice_init(&rchan->desc.wait, &list);
rchan->desc.running = NULL;
list_for_each_entry(desc, &list, node)
rcar_dmac_realloc_hwdesc(rchan, desc, 0);
list_for_each_entry_safe(page, _page, &rchan->desc.pages, node) {
list_del(&page->node);
free_page((unsigned long)page);
}
/* Remove slave mapping if present. */
if (map->slave.xfer_size) {
dma_unmap_resource(chan->device->dev, map->addr,
map->slave.xfer_size, map->dir, 0);
map->slave.xfer_size = 0;
}
pm_runtime_put(chan->device->dev);
}
static struct dma_async_tx_descriptor *
rcar_dmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dma_dest,
dma_addr_t dma_src, size_t len, unsigned long flags)
{
struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
struct scatterlist sgl;
if (!len)
return NULL;
sg_init_table(&sgl, 1);
sg_set_page(&sgl, pfn_to_page(PFN_DOWN(dma_src)), len,
offset_in_page(dma_src));
sg_dma_address(&sgl) = dma_src;
sg_dma_len(&sgl) = len;
return rcar_dmac_chan_prep_sg(rchan, &sgl, 1, dma_dest,
DMA_MEM_TO_MEM, flags, false);
}
static int rcar_dmac_map_slave_addr(struct dma_chan *chan,
enum dma_transfer_direction dir)
{
struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
struct rcar_dmac_chan_map *map = &rchan->map;
phys_addr_t dev_addr;
size_t dev_size;
enum dma_data_direction dev_dir;
if (dir == DMA_DEV_TO_MEM) {
dev_addr = rchan->src.slave_addr;
dev_size = rchan->src.xfer_size;
dev_dir = DMA_TO_DEVICE;
} else {
dev_addr = rchan->dst.slave_addr;
dev_size = rchan->dst.xfer_size;
dev_dir = DMA_FROM_DEVICE;
}
/* Reuse current map if possible. */
if (dev_addr == map->slave.slave_addr &&
dev_size == map->slave.xfer_size &&
dev_dir == map->dir)
return 0;
/* Remove old mapping if present. */
if (map->slave.xfer_size)
dma_unmap_resource(chan->device->dev, map->addr,
map->slave.xfer_size, map->dir, 0);
map->slave.xfer_size = 0;
/* Create new slave address map. */
map->addr = dma_map_resource(chan->device->dev, dev_addr, dev_size,
dev_dir, 0);
if (dma_mapping_error(chan->device->dev, map->addr)) {
dev_err(chan->device->dev,
"chan%u: failed to map %zx@%pap", rchan->index,
dev_size, &dev_addr);
return -EIO;
}
dev_dbg(chan->device->dev, "chan%u: map %zx@%pap to %pad dir: %s\n",
rchan->index, dev_size, &dev_addr, &map->addr,
dev_dir == DMA_TO_DEVICE ? "DMA_TO_DEVICE" : "DMA_FROM_DEVICE");
map->slave.slave_addr = dev_addr;
map->slave.xfer_size = dev_size;
map->dir = dev_dir;
return 0;
}
static struct dma_async_tx_descriptor *
rcar_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
unsigned int sg_len, enum dma_transfer_direction dir,
unsigned long flags, void *context)
{
struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
/* Someone calling slave DMA on a generic channel? */
if (rchan->mid_rid < 0 || !sg_len || !sg_dma_len(sgl)) {
dev_warn(chan->device->dev,
"%s: bad parameter: len=%d, id=%d\n",
__func__, sg_len, rchan->mid_rid);
return NULL;
}
if (rcar_dmac_map_slave_addr(chan, dir))
return NULL;
return rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, rchan->map.addr,
dir, flags, false);
}
#define RCAR_DMAC_MAX_SG_LEN 32
static struct dma_async_tx_descriptor *
rcar_dmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr,
size_t buf_len, size_t period_len,
enum dma_transfer_direction dir, unsigned long flags)
{
struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
struct dma_async_tx_descriptor *desc;
struct scatterlist *sgl;
unsigned int sg_len;
unsigned int i;
/* Someone calling slave DMA on a generic channel? */
if (rchan->mid_rid < 0 || buf_len < period_len) {
dev_warn(chan->device->dev,
"%s: bad parameter: buf_len=%zu, period_len=%zu, id=%d\n",
__func__, buf_len, period_len, rchan->mid_rid);
return NULL;
}
if (rcar_dmac_map_slave_addr(chan, dir))
return NULL;
sg_len = buf_len / period_len;
if (sg_len > RCAR_DMAC_MAX_SG_LEN) {
dev_err(chan->device->dev,
"chan%u: sg length %d exceeds limit %d",
rchan->index, sg_len, RCAR_DMAC_MAX_SG_LEN);
return NULL;
}
/*
* Allocate the sg list dynamically as it would consume too much stack
* space.
*/
sgl = kmalloc_array(sg_len, sizeof(*sgl), GFP_NOWAIT);
if (!sgl)
return NULL;
sg_init_table(sgl, sg_len);
for (i = 0; i < sg_len; ++i) {
dma_addr_t src = buf_addr + (period_len * i);
sg_set_page(&sgl[i], pfn_to_page(PFN_DOWN(src)), period_len,
offset_in_page(src));
sg_dma_address(&sgl[i]) = src;
sg_dma_len(&sgl[i]) = period_len;
}
desc = rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, rchan->map.addr,
dir, flags, true);
kfree(sgl);
return desc;
}
static int rcar_dmac_device_config(struct dma_chan *chan,
struct dma_slave_config *cfg)
{
struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
/*
* We could lock this, but you shouldn't be configuring the
* channel, while using it...
*/
rchan->src.slave_addr = cfg->src_addr;
rchan->dst.slave_addr = cfg->dst_addr;
rchan->src.xfer_size = cfg->src_addr_width;
rchan->dst.xfer_size = cfg->dst_addr_width;
return 0;
}
static int rcar_dmac_chan_terminate_all(struct dma_chan *chan)
{
struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
unsigned long flags;
spin_lock_irqsave(&rchan->lock, flags);
rcar_dmac_chan_halt(rchan);
spin_unlock_irqrestore(&rchan->lock, flags);
/*
* FIXME: No new interrupt can occur now, but the IRQ thread might still
* be running.
*/
rcar_dmac_chan_reinit(rchan);
return 0;
}
static unsigned int rcar_dmac_chan_get_residue(struct rcar_dmac_chan *chan,
dma_cookie_t cookie)
{
struct rcar_dmac_desc *desc = chan->desc.running;
struct rcar_dmac_xfer_chunk *running = NULL;
struct rcar_dmac_xfer_chunk *chunk;
enum dma_status status;
unsigned int residue = 0;
unsigned int dptr = 0;
unsigned int chcrb;
unsigned int tcrb;
unsigned int i;
if (!desc)
return 0;
/*
* If the cookie corresponds to a descriptor that has been completed
* there is no residue. The same check has already been performed by the
* caller but without holding the channel lock, so the descriptor could
* now be complete.
*/
status = dma_cookie_status(&chan->chan, cookie, NULL);
if (status == DMA_COMPLETE)
return 0;
/*
* If the cookie doesn't correspond to the currently running transfer
* then the descriptor hasn't been processed yet, and the residue is
* equal to the full descriptor size.
* Also, a client driver is possible to call this function before
* rcar_dmac_isr_channel_thread() runs. In this case, the "desc.running"
* will be the next descriptor, and the done list will appear. So, if
* the argument cookie matches the done list's cookie, we can assume
* the residue is zero.
*/
if (cookie != desc->async_tx.cookie) {
list_for_each_entry(desc, &chan->desc.done, node) {
if (cookie == desc->async_tx.cookie)
return 0;
}
list_for_each_entry(desc, &chan->desc.pending, node) {
if (cookie == desc->async_tx.cookie)
return desc->size;
}
list_for_each_entry(desc, &chan->desc.active, node) {
if (cookie == desc->async_tx.cookie)
return desc->size;
}
/*
* No descriptor found for the cookie, there's thus no residue.
* This shouldn't happen if the calling driver passes a correct
* cookie value.
*/
WARN(1, "No descriptor for cookie!");
return 0;
}
/*
* We need to read two registers.
* Make sure the control register does not skip to next chunk
* while reading the counter.
* Trying it 3 times should be enough: Initial read, retry, retry
* for the paranoid.
*/
for (i = 0; i < 3; i++) {
chcrb = rcar_dmac_chan_read(chan, RCAR_DMACHCRB) &
RCAR_DMACHCRB_DPTR_MASK;
tcrb = rcar_dmac_chan_read(chan, RCAR_DMATCRB);
/* Still the same? */
if (chcrb == (rcar_dmac_chan_read(chan, RCAR_DMACHCRB) &
RCAR_DMACHCRB_DPTR_MASK))
break;
}
WARN_ONCE(i >= 3, "residue might be not continuous!");
/*
* In descriptor mode the descriptor running pointer is not maintained
* by the interrupt handler, find the running descriptor from the
* descriptor pointer field in the CHCRB register. In non-descriptor
* mode just use the running descriptor pointer.
*/
if (desc->hwdescs.use) {
dptr = chcrb >> RCAR_DMACHCRB_DPTR_SHIFT;
if (dptr == 0)
dptr = desc->nchunks;
dptr--;
WARN_ON(dptr >= desc->nchunks);
} else {
running = desc->running;
}
/* Compute the size of all chunks still to be transferred. */
list_for_each_entry_reverse(chunk, &desc->chunks, node) {
if (chunk == running || ++dptr == desc->nchunks)
break;
residue += chunk->size;
}
/* Add the residue for the current chunk. */
residue += tcrb << desc->xfer_shift;
return residue;
}
static enum dma_status rcar_dmac_tx_status(struct dma_chan *chan,
dma_cookie_t cookie,
struct dma_tx_state *txstate)
{
struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
enum dma_status status;
unsigned long flags;
unsigned int residue;
bool cyclic;
status = dma_cookie_status(chan, cookie, txstate);
if (status == DMA_COMPLETE || !txstate)
return status;
spin_lock_irqsave(&rchan->lock, flags);
residue = rcar_dmac_chan_get_residue(rchan, cookie);
cyclic = rchan->desc.running ? rchan->desc.running->cyclic : false;
spin_unlock_irqrestore(&rchan->lock, flags);
/* if there's no residue, the cookie is complete */
if (!residue && !cyclic)
return DMA_COMPLETE;
dma_set_residue(txstate, residue);
return status;
}
static void rcar_dmac_issue_pending(struct dma_chan *chan)
{
struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
unsigned long flags;
spin_lock_irqsave(&rchan->lock, flags);
if (list_empty(&rchan->desc.pending))
goto done;
/* Append the pending list to the active list. */
list_splice_tail_init(&rchan->desc.pending, &rchan->desc.active);
/*
* If no transfer is running pick the first descriptor from the active
* list and start the transfer.
*/
if (!rchan->desc.running) {
struct rcar_dmac_desc *desc;
desc = list_first_entry(&rchan->desc.active,
struct rcar_dmac_desc, node);
rchan->desc.running = desc;
rcar_dmac_chan_start_xfer(rchan);
}
done:
spin_unlock_irqrestore(&rchan->lock, flags);
}
static void rcar_dmac_device_synchronize(struct dma_chan *chan)
{
struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
synchronize_irq(rchan->irq);
}
/* -----------------------------------------------------------------------------
* IRQ handling
*/
static irqreturn_t rcar_dmac_isr_desc_stage_end(struct rcar_dmac_chan *chan)
{
struct rcar_dmac_desc *desc = chan->desc.running;
unsigned int stage;
if (WARN_ON(!desc || !desc->cyclic)) {
/*
* This should never happen, there should always be a running
* cyclic descriptor when a descriptor stage end interrupt is
* triggered. Warn and return.
*/
return IRQ_NONE;
}
/* Program the interrupt pointer to the next stage. */
stage = (rcar_dmac_chan_read(chan, RCAR_DMACHCRB) &
RCAR_DMACHCRB_DPTR_MASK) >> RCAR_DMACHCRB_DPTR_SHIFT;
rcar_dmac_chan_write(chan, RCAR_DMADPCR, RCAR_DMADPCR_DIPT(stage));
return IRQ_WAKE_THREAD;
}
static irqreturn_t rcar_dmac_isr_transfer_end(struct rcar_dmac_chan *chan)
{
struct rcar_dmac_desc *desc = chan->desc.running;
irqreturn_t ret = IRQ_WAKE_THREAD;
if (WARN_ON_ONCE(!desc)) {
/*
* This should never happen, there should always be a running
* descriptor when a transfer end interrupt is triggered. Warn
* and return.
*/
return IRQ_NONE;
}
/*
* The transfer end interrupt isn't generated for each chunk when using
* descriptor mode. Only update the running chunk pointer in
* non-descriptor mode.
*/
if (!desc->hwdescs.use) {
/*
* If we haven't completed the last transfer chunk simply move
* to the next one. Only wake the IRQ thread if the transfer is
* cyclic.
*/
if (!list_is_last(&desc->running->node, &desc->chunks)) {
desc->running = list_next_entry(desc->running, node);
if (!desc->cyclic)
ret = IRQ_HANDLED;
goto done;
}
/*
* We've completed the last transfer chunk. If the transfer is
* cyclic, move back to the first one.
*/
if (desc->cyclic) {
desc->running =
list_first_entry(&desc->chunks,
struct rcar_dmac_xfer_chunk,
node);
goto done;
}
}
/* The descriptor is complete, move it to the done list. */
list_move_tail(&desc->node, &chan->desc.done);
/* Queue the next descriptor, if any. */
if (!list_empty(&chan->desc.active))
chan->desc.running = list_first_entry(&chan->desc.active,
struct rcar_dmac_desc,
node);
else
chan->desc.running = NULL;
done:
if (chan->desc.running)
rcar_dmac_chan_start_xfer(chan);
return ret;
}
static irqreturn_t rcar_dmac_isr_channel(int irq, void *dev)
{
u32 mask = RCAR_DMACHCR_DSE | RCAR_DMACHCR_TE;
struct rcar_dmac_chan *chan = dev;
irqreturn_t ret = IRQ_NONE;
bool reinit = false;
u32 chcr;
spin_lock(&chan->lock);
chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
if (chcr & RCAR_DMACHCR_CAE) {
struct rcar_dmac *dmac = to_rcar_dmac(chan->chan.device);
/*
* We don't need to call rcar_dmac_chan_halt()
* because channel is already stopped in error case.
* We need to clear register and check DE bit as recovery.
*/
rcar_dmac_chan_clear(dmac, chan);
rcar_dmac_chcr_de_barrier(chan);
reinit = true;
goto spin_lock_end;
}
if (chcr & RCAR_DMACHCR_TE)
mask |= RCAR_DMACHCR_DE;
rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr & ~mask);
if (mask & RCAR_DMACHCR_DE)
rcar_dmac_chcr_de_barrier(chan);
if (chcr & RCAR_DMACHCR_DSE)
ret |= rcar_dmac_isr_desc_stage_end(chan);
if (chcr & RCAR_DMACHCR_TE)
ret |= rcar_dmac_isr_transfer_end(chan);
spin_lock_end:
spin_unlock(&chan->lock);
if (reinit) {
dev_err(chan->chan.device->dev, "Channel Address Error\n");
rcar_dmac_chan_reinit(chan);
ret = IRQ_HANDLED;
}
return ret;
}
static irqreturn_t rcar_dmac_isr_channel_thread(int irq, void *dev)
{
struct rcar_dmac_chan *chan = dev;
struct rcar_dmac_desc *desc;
struct dmaengine_desc_callback cb;
spin_lock_irq(&chan->lock);
/* For cyclic transfers notify the user after every chunk. */
if (chan->desc.running && chan->desc.running->cyclic) {
desc = chan->desc.running;
dmaengine_desc_get_callback(&desc->async_tx, &cb);
if (dmaengine_desc_callback_valid(&cb)) {
spin_unlock_irq(&chan->lock);
dmaengine_desc_callback_invoke(&cb, NULL);
spin_lock_irq(&chan->lock);
}
}
/*
* Call the callback function for all descriptors on the done list and
* move them to the ack wait list.
*/
while (!list_empty(&chan->desc.done)) {
desc = list_first_entry(&chan->desc.done, struct rcar_dmac_desc,
node);
dma_cookie_complete(&desc->async_tx);
list_del(&desc->node);
dmaengine_desc_get_callback(&desc->async_tx, &cb);
if (dmaengine_desc_callback_valid(&cb)) {
spin_unlock_irq(&chan->lock);
/*
* We own the only reference to this descriptor, we can
* safely dereference it without holding the channel
* lock.
*/
dmaengine_desc_callback_invoke(&cb, NULL);
spin_lock_irq(&chan->lock);
}
list_add_tail(&desc->node, &chan->desc.wait);
}
spin_unlock_irq(&chan->lock);
/* Recycle all acked descriptors. */
rcar_dmac_desc_recycle_acked(chan);
return IRQ_HANDLED;
}
/* -----------------------------------------------------------------------------
* OF xlate and channel filter
*/
static bool rcar_dmac_chan_filter(struct dma_chan *chan, void *arg)
{
struct rcar_dmac *dmac = to_rcar_dmac(chan->device);
struct of_phandle_args *dma_spec = arg;
/*
* FIXME: Using a filter on OF platforms is a nonsense. The OF xlate
* function knows from which device it wants to allocate a channel from,
* and would be perfectly capable of selecting the channel it wants.
* Forcing it to call dma_request_channel() and iterate through all
* channels from all controllers is just pointless.
*/
if (chan->device->device_config != rcar_dmac_device_config)
return false;
return !test_and_set_bit(dma_spec->args[0], dmac->modules);
}
static struct dma_chan *rcar_dmac_of_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma)
{
struct rcar_dmac_chan *rchan;
struct dma_chan *chan;
dma_cap_mask_t mask;
if (dma_spec->args_count != 1)
return NULL;
/* Only slave DMA channels can be allocated via DT */
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
chan = __dma_request_channel(&mask, rcar_dmac_chan_filter, dma_spec,
ofdma->of_node);
if (!chan)
return NULL;
rchan = to_rcar_dmac_chan(chan);
rchan->mid_rid = dma_spec->args[0];
return chan;
}
/* -----------------------------------------------------------------------------
* Power management
*/
#ifdef CONFIG_PM
static int rcar_dmac_runtime_suspend(struct device *dev)
{
return 0;
}
static int rcar_dmac_runtime_resume(struct device *dev)
{
struct rcar_dmac *dmac = dev_get_drvdata(dev);
return rcar_dmac_init(dmac);
}
#endif
static const struct dev_pm_ops rcar_dmac_pm = {
/*
* TODO for system sleep/resume:
* - Wait for the current transfer to complete and stop the device,
* - Resume transfers, if any.
*/
SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
pm_runtime_force_resume)
SET_RUNTIME_PM_OPS(rcar_dmac_runtime_suspend, rcar_dmac_runtime_resume,
NULL)
};
/* -----------------------------------------------------------------------------
* Probe and remove
*/
static int rcar_dmac_chan_probe(struct rcar_dmac *dmac,
struct rcar_dmac_chan *rchan)
{
struct platform_device *pdev = to_platform_device(dmac->dev);
struct dma_chan *chan = &rchan->chan;
char pdev_irqname[5];
char *irqname;
int ret;
rchan->mid_rid = -EINVAL;
spin_lock_init(&rchan->lock);
INIT_LIST_HEAD(&rchan->desc.free);
INIT_LIST_HEAD(&rchan->desc.pending);
INIT_LIST_HEAD(&rchan->desc.active);
INIT_LIST_HEAD(&rchan->desc.done);
INIT_LIST_HEAD(&rchan->desc.wait);
/* Request the channel interrupt. */
sprintf(pdev_irqname, "ch%u", rchan->index);
rchan->irq = platform_get_irq_byname(pdev, pdev_irqname);
if (rchan->irq < 0)
return -ENODEV;
irqname = devm_kasprintf(dmac->dev, GFP_KERNEL, "%s:%u",
dev_name(dmac->dev), rchan->index);
if (!irqname)
return -ENOMEM;
/*
* Initialize the DMA engine channel and add it to the DMA engine
* channels list.
*/
chan->device = &dmac->engine;
dma_cookie_init(chan);
list_add_tail(&chan->device_node, &dmac->engine.channels);
ret = devm_request_threaded_irq(dmac->dev, rchan->irq,
rcar_dmac_isr_channel,
rcar_dmac_isr_channel_thread, 0,
irqname, rchan);
if (ret) {
dev_err(dmac->dev, "failed to request IRQ %u (%d)\n",
rchan->irq, ret);
return ret;
}
return 0;
}
#define RCAR_DMAC_MAX_CHANNELS 32
static int rcar_dmac_parse_of(struct device *dev, struct rcar_dmac *dmac)
{
struct device_node *np = dev->of_node;
int ret;
ret = of_property_read_u32(np, "dma-channels", &dmac->n_channels);
if (ret < 0) {
dev_err(dev, "unable to read dma-channels property\n");
return ret;
}
/* The hardware and driver don't support more than 32 bits in CHCLR */
if (dmac->n_channels <= 0 ||
dmac->n_channels >= RCAR_DMAC_MAX_CHANNELS) {
dev_err(dev, "invalid number of channels %u\n",
dmac->n_channels);
return -EINVAL;
}
/*
* If the driver is unable to read dma-channel-mask property,
* the driver assumes that it can use all channels.
*/
dmac->channels_mask = GENMASK(dmac->n_channels - 1, 0);
of_property_read_u32(np, "dma-channel-mask", &dmac->channels_mask);
/* If the property has out-of-channel mask, this driver clears it */
dmac->channels_mask &= GENMASK(dmac->n_channels - 1, 0);
return 0;
}
static int rcar_dmac_probe(struct platform_device *pdev)
{
const enum dma_slave_buswidth widths = DMA_SLAVE_BUSWIDTH_1_BYTE |
DMA_SLAVE_BUSWIDTH_2_BYTES | DMA_SLAVE_BUSWIDTH_4_BYTES |
DMA_SLAVE_BUSWIDTH_8_BYTES | DMA_SLAVE_BUSWIDTH_16_BYTES |
DMA_SLAVE_BUSWIDTH_32_BYTES | DMA_SLAVE_BUSWIDTH_64_BYTES;
const struct rcar_dmac_of_data *data;
struct rcar_dmac_chan *chan;
struct dma_device *engine;
void __iomem *chan_base;
struct rcar_dmac *dmac;
unsigned int i;
int ret;
data = of_device_get_match_data(&pdev->dev);
if (!data)
return -EINVAL;
dmac = devm_kzalloc(&pdev->dev, sizeof(*dmac), GFP_KERNEL);
if (!dmac)
return -ENOMEM;
dmac->dev = &pdev->dev;
platform_set_drvdata(pdev, dmac);
dma_set_max_seg_size(dmac->dev, RCAR_DMATCR_MASK);
dma_set_mask_and_coherent(dmac->dev, DMA_BIT_MASK(40));
ret = rcar_dmac_parse_of(&pdev->dev, dmac);
if (ret < 0)
return ret;
/*
* A still unconfirmed hardware bug prevents the IPMMU microTLB 0 to be
* flushed correctly, resulting in memory corruption. DMAC 0 channel 0
* is connected to microTLB 0 on currently supported platforms, so we
* can't use it with the IPMMU. As the IOMMU API operates at the device
* level we can't disable it selectively, so ignore channel 0 for now if
* the device is part of an IOMMU group.
*/
if (device_iommu_mapped(&pdev->dev))
dmac->channels_mask &= ~BIT(0);
dmac->channels = devm_kcalloc(&pdev->dev, dmac->n_channels,
sizeof(*dmac->channels), GFP_KERNEL);
if (!dmac->channels)
return -ENOMEM;
/* Request resources. */
dmac->dmac_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(dmac->dmac_base))
return PTR_ERR(dmac->dmac_base);
if (!data->chan_offset_base) {
dmac->chan_base = devm_platform_ioremap_resource(pdev, 1);
if (IS_ERR(dmac->chan_base))
return PTR_ERR(dmac->chan_base);
chan_base = dmac->chan_base;
} else {
chan_base = dmac->dmac_base + data->chan_offset_base;
}
for_each_rcar_dmac_chan(i, dmac, chan) {
chan->index = i;
chan->iomem = chan_base + i * data->chan_offset_stride;
}
/* Enable runtime PM and initialize the device. */
pm_runtime_enable(&pdev->dev);
ret = pm_runtime_get_sync(&pdev->dev);
if (ret < 0) {
dev_err(&pdev->dev, "runtime PM get sync failed (%d)\n", ret);
return ret;
}
ret = rcar_dmac_init(dmac);
pm_runtime_put(&pdev->dev);
if (ret) {
dev_err(&pdev->dev, "failed to reset device\n");
goto error;
}
/* Initialize engine */
engine = &dmac->engine;
dma_cap_set(DMA_MEMCPY, engine->cap_mask);
dma_cap_set(DMA_SLAVE, engine->cap_mask);
engine->dev = &pdev->dev;
engine->copy_align = ilog2(RCAR_DMAC_MEMCPY_XFER_SIZE);
engine->src_addr_widths = widths;
engine->dst_addr_widths = widths;
engine->directions = BIT(DMA_MEM_TO_DEV) | BIT(DMA_DEV_TO_MEM);
engine->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
engine->device_alloc_chan_resources = rcar_dmac_alloc_chan_resources;
engine->device_free_chan_resources = rcar_dmac_free_chan_resources;
engine->device_prep_dma_memcpy = rcar_dmac_prep_dma_memcpy;
engine->device_prep_slave_sg = rcar_dmac_prep_slave_sg;
engine->device_prep_dma_cyclic = rcar_dmac_prep_dma_cyclic;
engine->device_config = rcar_dmac_device_config;
engine->device_pause = rcar_dmac_chan_pause;
engine->device_terminate_all = rcar_dmac_chan_terminate_all;
engine->device_tx_status = rcar_dmac_tx_status;
engine->device_issue_pending = rcar_dmac_issue_pending;
engine->device_synchronize = rcar_dmac_device_synchronize;
INIT_LIST_HEAD(&engine->channels);
for_each_rcar_dmac_chan(i, dmac, chan) {
ret = rcar_dmac_chan_probe(dmac, chan);
if (ret < 0)
goto error;
}
/* Register the DMAC as a DMA provider for DT. */
ret = of_dma_controller_register(pdev->dev.of_node, rcar_dmac_of_xlate,
NULL);
if (ret < 0)
goto error;
/*
* Register the DMA engine device.
*
* Default transfer size of 32 bytes requires 32-byte alignment.
*/
ret = dma_async_device_register(engine);
if (ret < 0)
goto error;
return 0;
error:
of_dma_controller_free(pdev->dev.of_node);
pm_runtime_disable(&pdev->dev);
return ret;
}
static int rcar_dmac_remove(struct platform_device *pdev)
{
struct rcar_dmac *dmac = platform_get_drvdata(pdev);
of_dma_controller_free(pdev->dev.of_node);
dma_async_device_unregister(&dmac->engine);
pm_runtime_disable(&pdev->dev);
return 0;
}
static void rcar_dmac_shutdown(struct platform_device *pdev)
{
struct rcar_dmac *dmac = platform_get_drvdata(pdev);
rcar_dmac_stop_all_chan(dmac);
}
static const struct rcar_dmac_of_data rcar_dmac_data = {
.chan_offset_base = 0x8000,
.chan_offset_stride = 0x80,
};
static const struct rcar_dmac_of_data rcar_v3u_dmac_data = {
.chan_offset_base = 0x0,
.chan_offset_stride = 0x1000,
};
static const struct of_device_id rcar_dmac_of_ids[] = {
{
.compatible = "renesas,rcar-dmac",
.data = &rcar_dmac_data,
}, {
.compatible = "renesas,dmac-r8a779a0",
.data = &rcar_v3u_dmac_data,
},
{ /* Sentinel */ }
};
MODULE_DEVICE_TABLE(of, rcar_dmac_of_ids);
static struct platform_driver rcar_dmac_driver = {
.driver = {
.pm = &rcar_dmac_pm,
.name = "rcar-dmac",
.of_match_table = rcar_dmac_of_ids,
},
.probe = rcar_dmac_probe,
.remove = rcar_dmac_remove,
.shutdown = rcar_dmac_shutdown,
};
module_platform_driver(rcar_dmac_driver);
MODULE_DESCRIPTION("R-Car Gen2 DMA Controller Driver");
MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
MODULE_LICENSE("GPL v2");
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