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kernel/drivers/dma/ep93xx_dma.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Driver for the Cirrus Logic EP93xx DMA Controller
*
* Copyright (C) 2011 Mika Westerberg
*
* DMA M2P implementation is based on the original
* arch/arm/mach-ep93xx/dma-m2p.c which has following copyrights:
*
* Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
* Copyright (C) 2006 Applied Data Systems
* Copyright (C) 2009 Ryan Mallon <rmallon@gmail.com>
*
* This driver is based on dw_dmac and amba-pl08x drivers.
*/
#include <linux/clk.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/dmaengine.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/platform_data/dma-ep93xx.h>
#include "dmaengine.h"
/* M2P registers */
#define M2P_CONTROL 0x0000
#define M2P_CONTROL_STALLINT BIT(0)
#define M2P_CONTROL_NFBINT BIT(1)
#define M2P_CONTROL_CH_ERROR_INT BIT(3)
#define M2P_CONTROL_ENABLE BIT(4)
#define M2P_CONTROL_ICE BIT(6)
#define M2P_INTERRUPT 0x0004
#define M2P_INTERRUPT_STALL BIT(0)
#define M2P_INTERRUPT_NFB BIT(1)
#define M2P_INTERRUPT_ERROR BIT(3)
#define M2P_PPALLOC 0x0008
#define M2P_STATUS 0x000c
#define M2P_MAXCNT0 0x0020
#define M2P_BASE0 0x0024
#define M2P_MAXCNT1 0x0030
#define M2P_BASE1 0x0034
#define M2P_STATE_IDLE 0
#define M2P_STATE_STALL 1
#define M2P_STATE_ON 2
#define M2P_STATE_NEXT 3
/* M2M registers */
#define M2M_CONTROL 0x0000
#define M2M_CONTROL_DONEINT BIT(2)
#define M2M_CONTROL_ENABLE BIT(3)
#define M2M_CONTROL_START BIT(4)
#define M2M_CONTROL_DAH BIT(11)
#define M2M_CONTROL_SAH BIT(12)
#define M2M_CONTROL_PW_SHIFT 9
#define M2M_CONTROL_PW_8 (0 << M2M_CONTROL_PW_SHIFT)
#define M2M_CONTROL_PW_16 (1 << M2M_CONTROL_PW_SHIFT)
#define M2M_CONTROL_PW_32 (2 << M2M_CONTROL_PW_SHIFT)
#define M2M_CONTROL_PW_MASK (3 << M2M_CONTROL_PW_SHIFT)
#define M2M_CONTROL_TM_SHIFT 13
#define M2M_CONTROL_TM_TX (1 << M2M_CONTROL_TM_SHIFT)
#define M2M_CONTROL_TM_RX (2 << M2M_CONTROL_TM_SHIFT)
#define M2M_CONTROL_NFBINT BIT(21)
#define M2M_CONTROL_RSS_SHIFT 22
#define M2M_CONTROL_RSS_SSPRX (1 << M2M_CONTROL_RSS_SHIFT)
#define M2M_CONTROL_RSS_SSPTX (2 << M2M_CONTROL_RSS_SHIFT)
#define M2M_CONTROL_RSS_IDE (3 << M2M_CONTROL_RSS_SHIFT)
#define M2M_CONTROL_NO_HDSK BIT(24)
#define M2M_CONTROL_PWSC_SHIFT 25
#define M2M_INTERRUPT 0x0004
#define M2M_INTERRUPT_MASK 6
#define M2M_STATUS 0x000c
#define M2M_STATUS_CTL_SHIFT 1
#define M2M_STATUS_CTL_IDLE (0 << M2M_STATUS_CTL_SHIFT)
#define M2M_STATUS_CTL_STALL (1 << M2M_STATUS_CTL_SHIFT)
#define M2M_STATUS_CTL_MEMRD (2 << M2M_STATUS_CTL_SHIFT)
#define M2M_STATUS_CTL_MEMWR (3 << M2M_STATUS_CTL_SHIFT)
#define M2M_STATUS_CTL_BWCWAIT (4 << M2M_STATUS_CTL_SHIFT)
#define M2M_STATUS_CTL_MASK (7 << M2M_STATUS_CTL_SHIFT)
#define M2M_STATUS_BUF_SHIFT 4
#define M2M_STATUS_BUF_NO (0 << M2M_STATUS_BUF_SHIFT)
#define M2M_STATUS_BUF_ON (1 << M2M_STATUS_BUF_SHIFT)
#define M2M_STATUS_BUF_NEXT (2 << M2M_STATUS_BUF_SHIFT)
#define M2M_STATUS_BUF_MASK (3 << M2M_STATUS_BUF_SHIFT)
#define M2M_STATUS_DONE BIT(6)
#define M2M_BCR0 0x0010
#define M2M_BCR1 0x0014
#define M2M_SAR_BASE0 0x0018
#define M2M_SAR_BASE1 0x001c
#define M2M_DAR_BASE0 0x002c
#define M2M_DAR_BASE1 0x0030
#define DMA_MAX_CHAN_BYTES 0xffff
#define DMA_MAX_CHAN_DESCRIPTORS 32
struct ep93xx_dma_engine;
static int ep93xx_dma_slave_config_write(struct dma_chan *chan,
enum dma_transfer_direction dir,
struct dma_slave_config *config);
/**
* struct ep93xx_dma_desc - EP93xx specific transaction descriptor
* @src_addr: source address of the transaction
* @dst_addr: destination address of the transaction
* @size: size of the transaction (in bytes)
* @complete: this descriptor is completed
* @txd: dmaengine API descriptor
* @tx_list: list of linked descriptors
* @node: link used for putting this into a channel queue
*/
struct ep93xx_dma_desc {
u32 src_addr;
u32 dst_addr;
size_t size;
bool complete;
struct dma_async_tx_descriptor txd;
struct list_head tx_list;
struct list_head node;
};
/**
* struct ep93xx_dma_chan - an EP93xx DMA M2P/M2M channel
* @chan: dmaengine API channel
* @edma: pointer to to the engine device
* @regs: memory mapped registers
* @irq: interrupt number of the channel
* @clk: clock used by this channel
* @tasklet: channel specific tasklet used for callbacks
* @lock: lock protecting the fields following
* @flags: flags for the channel
* @buffer: which buffer to use next (0/1)
* @active: flattened chain of descriptors currently being processed
* @queue: pending descriptors which are handled next
* @free_list: list of free descriptors which can be used
* @runtime_addr: physical address currently used as dest/src (M2M only). This
* is set via .device_config before slave operation is
* prepared
* @runtime_ctrl: M2M runtime values for the control register.
* @slave_config: slave configuration
*
* As EP93xx DMA controller doesn't support real chained DMA descriptors we
* will have slightly different scheme here: @active points to a head of
* flattened DMA descriptor chain.
*
* @queue holds pending transactions. These are linked through the first
* descriptor in the chain. When a descriptor is moved to the @active queue,
* the first and chained descriptors are flattened into a single list.
*
* @chan.private holds pointer to &struct ep93xx_dma_data which contains
* necessary channel configuration information. For memcpy channels this must
* be %NULL.
*/
struct ep93xx_dma_chan {
struct dma_chan chan;
const struct ep93xx_dma_engine *edma;
void __iomem *regs;
int irq;
struct clk *clk;
struct tasklet_struct tasklet;
/* protects the fields following */
spinlock_t lock;
unsigned long flags;
/* Channel is configured for cyclic transfers */
#define EP93XX_DMA_IS_CYCLIC 0
int buffer;
struct list_head active;
struct list_head queue;
struct list_head free_list;
u32 runtime_addr;
u32 runtime_ctrl;
struct dma_slave_config slave_config;
};
/**
* struct ep93xx_dma_engine - the EP93xx DMA engine instance
* @dma_dev: holds the dmaengine device
* @m2m: is this an M2M or M2P device
* @hw_setup: method which sets the channel up for operation
* @hw_synchronize: synchronizes DMA channel termination to current context
* @hw_shutdown: shuts the channel down and flushes whatever is left
* @hw_submit: pushes active descriptor(s) to the hardware
* @hw_interrupt: handle the interrupt
* @num_channels: number of channels for this instance
* @channels: array of channels
*
* There is one instance of this struct for the M2P channels and one for the
* M2M channels. hw_xxx() methods are used to perform operations which are
* different on M2M and M2P channels. These methods are called with channel
* lock held and interrupts disabled so they cannot sleep.
*/
struct ep93xx_dma_engine {
struct dma_device dma_dev;
bool m2m;
int (*hw_setup)(struct ep93xx_dma_chan *);
void (*hw_synchronize)(struct ep93xx_dma_chan *);
void (*hw_shutdown)(struct ep93xx_dma_chan *);
void (*hw_submit)(struct ep93xx_dma_chan *);
int (*hw_interrupt)(struct ep93xx_dma_chan *);
#define INTERRUPT_UNKNOWN 0
#define INTERRUPT_DONE 1
#define INTERRUPT_NEXT_BUFFER 2
size_t num_channels;
struct ep93xx_dma_chan channels[];
};
static inline struct device *chan2dev(struct ep93xx_dma_chan *edmac)
{
return &edmac->chan.dev->device;
}
static struct ep93xx_dma_chan *to_ep93xx_dma_chan(struct dma_chan *chan)
{
return container_of(chan, struct ep93xx_dma_chan, chan);
}
/**
* ep93xx_dma_set_active - set new active descriptor chain
* @edmac: channel
* @desc: head of the new active descriptor chain
*
* Sets @desc to be the head of the new active descriptor chain. This is the
* chain which is processed next. The active list must be empty before calling
* this function.
*
* Called with @edmac->lock held and interrupts disabled.
*/
static void ep93xx_dma_set_active(struct ep93xx_dma_chan *edmac,
struct ep93xx_dma_desc *desc)
{
BUG_ON(!list_empty(&edmac->active));
list_add_tail(&desc->node, &edmac->active);
/* Flatten the @desc->tx_list chain into @edmac->active list */
while (!list_empty(&desc->tx_list)) {
struct ep93xx_dma_desc *d = list_first_entry(&desc->tx_list,
struct ep93xx_dma_desc, node);
/*
* We copy the callback parameters from the first descriptor
* to all the chained descriptors. This way we can call the
* callback without having to find out the first descriptor in
* the chain. Useful for cyclic transfers.
*/
d->txd.callback = desc->txd.callback;
d->txd.callback_param = desc->txd.callback_param;
list_move_tail(&d->node, &edmac->active);
}
}
/* Called with @edmac->lock held and interrupts disabled */
static struct ep93xx_dma_desc *
ep93xx_dma_get_active(struct ep93xx_dma_chan *edmac)
{
return list_first_entry_or_null(&edmac->active,
struct ep93xx_dma_desc, node);
}
/**
* ep93xx_dma_advance_active - advances to the next active descriptor
* @edmac: channel
*
* Function advances active descriptor to the next in the @edmac->active and
* returns %true if we still have descriptors in the chain to process.
* Otherwise returns %false.
*
* When the channel is in cyclic mode always returns %true.
*
* Called with @edmac->lock held and interrupts disabled.
*/
static bool ep93xx_dma_advance_active(struct ep93xx_dma_chan *edmac)
{
struct ep93xx_dma_desc *desc;
list_rotate_left(&edmac->active);
if (test_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags))
return true;
desc = ep93xx_dma_get_active(edmac);
if (!desc)
return false;
/*
* If txd.cookie is set it means that we are back in the first
* descriptor in the chain and hence done with it.
*/
return !desc->txd.cookie;
}
/*
* M2P DMA implementation
*/
static void m2p_set_control(struct ep93xx_dma_chan *edmac, u32 control)
{
writel(control, edmac->regs + M2P_CONTROL);
/*
* EP93xx User's Guide states that we must perform a dummy read after
* write to the control register.
*/
readl(edmac->regs + M2P_CONTROL);
}
static int m2p_hw_setup(struct ep93xx_dma_chan *edmac)
{
struct ep93xx_dma_data *data = edmac->chan.private;
u32 control;
writel(data->port & 0xf, edmac->regs + M2P_PPALLOC);
control = M2P_CONTROL_CH_ERROR_INT | M2P_CONTROL_ICE
| M2P_CONTROL_ENABLE;
m2p_set_control(edmac, control);
edmac->buffer = 0;
return 0;
}
static inline u32 m2p_channel_state(struct ep93xx_dma_chan *edmac)
{
return (readl(edmac->regs + M2P_STATUS) >> 4) & 0x3;
}
static void m2p_hw_synchronize(struct ep93xx_dma_chan *edmac)
{
unsigned long flags;
u32 control;
spin_lock_irqsave(&edmac->lock, flags);
control = readl(edmac->regs + M2P_CONTROL);
control &= ~(M2P_CONTROL_STALLINT | M2P_CONTROL_NFBINT);
m2p_set_control(edmac, control);
spin_unlock_irqrestore(&edmac->lock, flags);
while (m2p_channel_state(edmac) >= M2P_STATE_ON)
schedule();
}
static void m2p_hw_shutdown(struct ep93xx_dma_chan *edmac)
{
m2p_set_control(edmac, 0);
while (m2p_channel_state(edmac) != M2P_STATE_IDLE)
dev_warn(chan2dev(edmac), "M2P: Not yet IDLE\n");
}
static void m2p_fill_desc(struct ep93xx_dma_chan *edmac)
{
struct ep93xx_dma_desc *desc;
u32 bus_addr;
desc = ep93xx_dma_get_active(edmac);
if (!desc) {
dev_warn(chan2dev(edmac), "M2P: empty descriptor list\n");
return;
}
if (ep93xx_dma_chan_direction(&edmac->chan) == DMA_MEM_TO_DEV)
bus_addr = desc->src_addr;
else
bus_addr = desc->dst_addr;
if (edmac->buffer == 0) {
writel(desc->size, edmac->regs + M2P_MAXCNT0);
writel(bus_addr, edmac->regs + M2P_BASE0);
} else {
writel(desc->size, edmac->regs + M2P_MAXCNT1);
writel(bus_addr, edmac->regs + M2P_BASE1);
}
edmac->buffer ^= 1;
}
static void m2p_hw_submit(struct ep93xx_dma_chan *edmac)
{
u32 control = readl(edmac->regs + M2P_CONTROL);
m2p_fill_desc(edmac);
control |= M2P_CONTROL_STALLINT;
if (ep93xx_dma_advance_active(edmac)) {
m2p_fill_desc(edmac);
control |= M2P_CONTROL_NFBINT;
}
m2p_set_control(edmac, control);
}
static int m2p_hw_interrupt(struct ep93xx_dma_chan *edmac)
{
u32 irq_status = readl(edmac->regs + M2P_INTERRUPT);
u32 control;
if (irq_status & M2P_INTERRUPT_ERROR) {
struct ep93xx_dma_desc *desc = ep93xx_dma_get_active(edmac);
/* Clear the error interrupt */
writel(1, edmac->regs + M2P_INTERRUPT);
/*
* It seems that there is no easy way of reporting errors back
* to client so we just report the error here and continue as
* usual.
*
* Revisit this when there is a mechanism to report back the
* errors.
*/
dev_err(chan2dev(edmac),
"DMA transfer failed! Details:\n"
"\tcookie : %d\n"
"\tsrc_addr : 0x%08x\n"
"\tdst_addr : 0x%08x\n"
"\tsize : %zu\n",
desc->txd.cookie, desc->src_addr, desc->dst_addr,
desc->size);
}
/*
* Even latest E2 silicon revision sometimes assert STALL interrupt
* instead of NFB. Therefore we treat them equally, basing on the
* amount of data we still have to transfer.
*/
if (!(irq_status & (M2P_INTERRUPT_STALL | M2P_INTERRUPT_NFB)))
return INTERRUPT_UNKNOWN;
if (ep93xx_dma_advance_active(edmac)) {
m2p_fill_desc(edmac);
return INTERRUPT_NEXT_BUFFER;
}
/* Disable interrupts */
control = readl(edmac->regs + M2P_CONTROL);
control &= ~(M2P_CONTROL_STALLINT | M2P_CONTROL_NFBINT);
m2p_set_control(edmac, control);
return INTERRUPT_DONE;
}
/*
* M2M DMA implementation
*/
static int m2m_hw_setup(struct ep93xx_dma_chan *edmac)
{
const struct ep93xx_dma_data *data = edmac->chan.private;
u32 control = 0;
if (!data) {
/* This is memcpy channel, nothing to configure */
writel(control, edmac->regs + M2M_CONTROL);
return 0;
}
switch (data->port) {
case EP93XX_DMA_SSP:
/*
* This was found via experimenting - anything less than 5
* causes the channel to perform only a partial transfer which
* leads to problems since we don't get DONE interrupt then.
*/
control = (5 << M2M_CONTROL_PWSC_SHIFT);
control |= M2M_CONTROL_NO_HDSK;
if (data->direction == DMA_MEM_TO_DEV) {
control |= M2M_CONTROL_DAH;
control |= M2M_CONTROL_TM_TX;
control |= M2M_CONTROL_RSS_SSPTX;
} else {
control |= M2M_CONTROL_SAH;
control |= M2M_CONTROL_TM_RX;
control |= M2M_CONTROL_RSS_SSPRX;
}
break;
case EP93XX_DMA_IDE:
/*
* This IDE part is totally untested. Values below are taken
* from the EP93xx Users's Guide and might not be correct.
*/
if (data->direction == DMA_MEM_TO_DEV) {
/* Worst case from the UG */
control = (3 << M2M_CONTROL_PWSC_SHIFT);
control |= M2M_CONTROL_DAH;
control |= M2M_CONTROL_TM_TX;
} else {
control = (2 << M2M_CONTROL_PWSC_SHIFT);
control |= M2M_CONTROL_SAH;
control |= M2M_CONTROL_TM_RX;
}
control |= M2M_CONTROL_NO_HDSK;
control |= M2M_CONTROL_RSS_IDE;
control |= M2M_CONTROL_PW_16;
break;
default:
return -EINVAL;
}
writel(control, edmac->regs + M2M_CONTROL);
return 0;
}
static void m2m_hw_shutdown(struct ep93xx_dma_chan *edmac)
{
/* Just disable the channel */
writel(0, edmac->regs + M2M_CONTROL);
}
static void m2m_fill_desc(struct ep93xx_dma_chan *edmac)
{
struct ep93xx_dma_desc *desc;
desc = ep93xx_dma_get_active(edmac);
if (!desc) {
dev_warn(chan2dev(edmac), "M2M: empty descriptor list\n");
return;
}
if (edmac->buffer == 0) {
writel(desc->src_addr, edmac->regs + M2M_SAR_BASE0);
writel(desc->dst_addr, edmac->regs + M2M_DAR_BASE0);
writel(desc->size, edmac->regs + M2M_BCR0);
} else {
writel(desc->src_addr, edmac->regs + M2M_SAR_BASE1);
writel(desc->dst_addr, edmac->regs + M2M_DAR_BASE1);
writel(desc->size, edmac->regs + M2M_BCR1);
}
edmac->buffer ^= 1;
}
static void m2m_hw_submit(struct ep93xx_dma_chan *edmac)
{
struct ep93xx_dma_data *data = edmac->chan.private;
u32 control = readl(edmac->regs + M2M_CONTROL);
/*
* Since we allow clients to configure PW (peripheral width) we always
* clear PW bits here and then set them according what is given in
* the runtime configuration.
*/
control &= ~M2M_CONTROL_PW_MASK;
control |= edmac->runtime_ctrl;
m2m_fill_desc(edmac);
control |= M2M_CONTROL_DONEINT;
if (ep93xx_dma_advance_active(edmac)) {
m2m_fill_desc(edmac);
control |= M2M_CONTROL_NFBINT;
}
/*
* Now we can finally enable the channel. For M2M channel this must be
* done _after_ the BCRx registers are programmed.
*/
control |= M2M_CONTROL_ENABLE;
writel(control, edmac->regs + M2M_CONTROL);
if (!data) {
/*
* For memcpy channels the software trigger must be asserted
* in order to start the memcpy operation.
*/
control |= M2M_CONTROL_START;
writel(control, edmac->regs + M2M_CONTROL);
}
}
/*
* According to EP93xx User's Guide, we should receive DONE interrupt when all
* M2M DMA controller transactions complete normally. This is not always the
* case - sometimes EP93xx M2M DMA asserts DONE interrupt when the DMA channel
* is still running (channel Buffer FSM in DMA_BUF_ON state, and channel
* Control FSM in DMA_MEM_RD state, observed at least in IDE-DMA operation).
* In effect, disabling the channel when only DONE bit is set could stop
* currently running DMA transfer. To avoid this, we use Buffer FSM and
* Control FSM to check current state of DMA channel.
*/
static int m2m_hw_interrupt(struct ep93xx_dma_chan *edmac)
{
u32 status = readl(edmac->regs + M2M_STATUS);
u32 ctl_fsm = status & M2M_STATUS_CTL_MASK;
u32 buf_fsm = status & M2M_STATUS_BUF_MASK;
bool done = status & M2M_STATUS_DONE;
bool last_done;
u32 control;
struct ep93xx_dma_desc *desc;
/* Accept only DONE and NFB interrupts */
if (!(readl(edmac->regs + M2M_INTERRUPT) & M2M_INTERRUPT_MASK))
return INTERRUPT_UNKNOWN;
if (done) {
/* Clear the DONE bit */
writel(0, edmac->regs + M2M_INTERRUPT);
}
/*
* Check whether we are done with descriptors or not. This, together
* with DMA channel state, determines action to take in interrupt.
*/
desc = ep93xx_dma_get_active(edmac);
last_done = !desc || desc->txd.cookie;
/*
* Use M2M DMA Buffer FSM and Control FSM to check current state of
* DMA channel. Using DONE and NFB bits from channel status register
* or bits from channel interrupt register is not reliable.
*/
if (!last_done &&
(buf_fsm == M2M_STATUS_BUF_NO ||
buf_fsm == M2M_STATUS_BUF_ON)) {
/*
* Two buffers are ready for update when Buffer FSM is in
* DMA_NO_BUF state. Only one buffer can be prepared without
* disabling the channel or polling the DONE bit.
* To simplify things, always prepare only one buffer.
*/
if (ep93xx_dma_advance_active(edmac)) {
m2m_fill_desc(edmac);
if (done && !edmac->chan.private) {
/* Software trigger for memcpy channel */
control = readl(edmac->regs + M2M_CONTROL);
control |= M2M_CONTROL_START;
writel(control, edmac->regs + M2M_CONTROL);
}
return INTERRUPT_NEXT_BUFFER;
} else {
last_done = true;
}
}
/*
* Disable the channel only when Buffer FSM is in DMA_NO_BUF state
* and Control FSM is in DMA_STALL state.
*/
if (last_done &&
buf_fsm == M2M_STATUS_BUF_NO &&
ctl_fsm == M2M_STATUS_CTL_STALL) {
/* Disable interrupts and the channel */
control = readl(edmac->regs + M2M_CONTROL);
control &= ~(M2M_CONTROL_DONEINT | M2M_CONTROL_NFBINT
| M2M_CONTROL_ENABLE);
writel(control, edmac->regs + M2M_CONTROL);
return INTERRUPT_DONE;
}
/*
* Nothing to do this time.
*/
return INTERRUPT_NEXT_BUFFER;
}
/*
* DMA engine API implementation
*/
static struct ep93xx_dma_desc *
ep93xx_dma_desc_get(struct ep93xx_dma_chan *edmac)
{
struct ep93xx_dma_desc *desc, *_desc;
struct ep93xx_dma_desc *ret = NULL;
unsigned long flags;
spin_lock_irqsave(&edmac->lock, flags);
list_for_each_entry_safe(desc, _desc, &edmac->free_list, node) {
if (async_tx_test_ack(&desc->txd)) {
list_del_init(&desc->node);
/* Re-initialize the descriptor */
desc->src_addr = 0;
desc->dst_addr = 0;
desc->size = 0;
desc->complete = false;
desc->txd.cookie = 0;
desc->txd.callback = NULL;
desc->txd.callback_param = NULL;
ret = desc;
break;
}
}
spin_unlock_irqrestore(&edmac->lock, flags);
return ret;
}
static void ep93xx_dma_desc_put(struct ep93xx_dma_chan *edmac,
struct ep93xx_dma_desc *desc)
{
if (desc) {
unsigned long flags;
spin_lock_irqsave(&edmac->lock, flags);
list_splice_init(&desc->tx_list, &edmac->free_list);
list_add(&desc->node, &edmac->free_list);
spin_unlock_irqrestore(&edmac->lock, flags);
}
}
/**
* ep93xx_dma_advance_work - start processing the next pending transaction
* @edmac: channel
*
* If we have pending transactions queued and we are currently idling, this
* function takes the next queued transaction from the @edmac->queue and
* pushes it to the hardware for execution.
*/
static void ep93xx_dma_advance_work(struct ep93xx_dma_chan *edmac)
{
struct ep93xx_dma_desc *new;
unsigned long flags;
spin_lock_irqsave(&edmac->lock, flags);
if (!list_empty(&edmac->active) || list_empty(&edmac->queue)) {
spin_unlock_irqrestore(&edmac->lock, flags);
return;
}
/* Take the next descriptor from the pending queue */
new = list_first_entry(&edmac->queue, struct ep93xx_dma_desc, node);
list_del_init(&new->node);
ep93xx_dma_set_active(edmac, new);
/* Push it to the hardware */
edmac->edma->hw_submit(edmac);
spin_unlock_irqrestore(&edmac->lock, flags);
}
static void ep93xx_dma_tasklet(struct tasklet_struct *t)
{
struct ep93xx_dma_chan *edmac = from_tasklet(edmac, t, tasklet);
struct ep93xx_dma_desc *desc, *d;
struct dmaengine_desc_callback cb;
LIST_HEAD(list);
memset(&cb, 0, sizeof(cb));
spin_lock_irq(&edmac->lock);
/*
* If dma_terminate_all() was called before we get to run, the active
* list has become empty. If that happens we aren't supposed to do
* anything more than call ep93xx_dma_advance_work().
*/
desc = ep93xx_dma_get_active(edmac);
if (desc) {
if (desc->complete) {
/* mark descriptor complete for non cyclic case only */
if (!test_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags))
dma_cookie_complete(&desc->txd);
list_splice_init(&edmac->active, &list);
}
dmaengine_desc_get_callback(&desc->txd, &cb);
}
spin_unlock_irq(&edmac->lock);
/* Pick up the next descriptor from the queue */
ep93xx_dma_advance_work(edmac);
/* Now we can release all the chained descriptors */
list_for_each_entry_safe(desc, d, &list, node) {
dma_descriptor_unmap(&desc->txd);
ep93xx_dma_desc_put(edmac, desc);
}
dmaengine_desc_callback_invoke(&cb, NULL);
}
static irqreturn_t ep93xx_dma_interrupt(int irq, void *dev_id)
{
struct ep93xx_dma_chan *edmac = dev_id;
struct ep93xx_dma_desc *desc;
irqreturn_t ret = IRQ_HANDLED;
spin_lock(&edmac->lock);
desc = ep93xx_dma_get_active(edmac);
if (!desc) {
dev_warn(chan2dev(edmac),
"got interrupt while active list is empty\n");
spin_unlock(&edmac->lock);
return IRQ_NONE;
}
switch (edmac->edma->hw_interrupt(edmac)) {
case INTERRUPT_DONE:
desc->complete = true;
tasklet_schedule(&edmac->tasklet);
break;
case INTERRUPT_NEXT_BUFFER:
if (test_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags))
tasklet_schedule(&edmac->tasklet);
break;
default:
dev_warn(chan2dev(edmac), "unknown interrupt!\n");
ret = IRQ_NONE;
break;
}
spin_unlock(&edmac->lock);
return ret;
}
/**
* ep93xx_dma_tx_submit - set the prepared descriptor(s) to be executed
* @tx: descriptor to be executed
*
* Function will execute given descriptor on the hardware or if the hardware
* is busy, queue the descriptor to be executed later on. Returns cookie which
* can be used to poll the status of the descriptor.
*/
static dma_cookie_t ep93xx_dma_tx_submit(struct dma_async_tx_descriptor *tx)
{
struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(tx->chan);
struct ep93xx_dma_desc *desc;
dma_cookie_t cookie;
unsigned long flags;
spin_lock_irqsave(&edmac->lock, flags);
cookie = dma_cookie_assign(tx);
desc = container_of(tx, struct ep93xx_dma_desc, txd);
/*
* If nothing is currently processed, we push this descriptor
* directly to the hardware. Otherwise we put the descriptor
* to the pending queue.
*/
if (list_empty(&edmac->active)) {
ep93xx_dma_set_active(edmac, desc);
edmac->edma->hw_submit(edmac);
} else {
list_add_tail(&desc->node, &edmac->queue);
}
spin_unlock_irqrestore(&edmac->lock, flags);
return cookie;
}
/**
* ep93xx_dma_alloc_chan_resources - allocate resources for the channel
* @chan: channel to allocate resources
*
* Function allocates necessary resources for the given DMA channel and
* returns number of allocated descriptors for the channel. Negative errno
* is returned in case of failure.
*/
static int ep93xx_dma_alloc_chan_resources(struct dma_chan *chan)
{
struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan);
struct ep93xx_dma_data *data = chan->private;
const char *name = dma_chan_name(chan);
int ret, i;
/* Sanity check the channel parameters */
if (!edmac->edma->m2m) {
if (!data)
return -EINVAL;
if (data->port < EP93XX_DMA_I2S1 ||
data->port > EP93XX_DMA_IRDA)
return -EINVAL;
if (data->direction != ep93xx_dma_chan_direction(chan))
return -EINVAL;
} else {
if (data) {
switch (data->port) {
case EP93XX_DMA_SSP:
case EP93XX_DMA_IDE:
if (!is_slave_direction(data->direction))
return -EINVAL;
break;
default:
return -EINVAL;
}
}
}
if (data && data->name)
name = data->name;
ret = clk_enable(edmac->clk);
if (ret)
return ret;
ret = request_irq(edmac->irq, ep93xx_dma_interrupt, 0, name, edmac);
if (ret)
goto fail_clk_disable;
spin_lock_irq(&edmac->lock);
dma_cookie_init(&edmac->chan);
ret = edmac->edma->hw_setup(edmac);
spin_unlock_irq(&edmac->lock);
if (ret)
goto fail_free_irq;
for (i = 0; i < DMA_MAX_CHAN_DESCRIPTORS; i++) {
struct ep93xx_dma_desc *desc;
desc = kzalloc(sizeof(*desc), GFP_KERNEL);
if (!desc) {
dev_warn(chan2dev(edmac), "not enough descriptors\n");
break;
}
INIT_LIST_HEAD(&desc->tx_list);
dma_async_tx_descriptor_init(&desc->txd, chan);
desc->txd.flags = DMA_CTRL_ACK;
desc->txd.tx_submit = ep93xx_dma_tx_submit;
ep93xx_dma_desc_put(edmac, desc);
}
return i;
fail_free_irq:
free_irq(edmac->irq, edmac);
fail_clk_disable:
clk_disable(edmac->clk);
return ret;
}
/**
* ep93xx_dma_free_chan_resources - release resources for the channel
* @chan: channel
*
* Function releases all the resources allocated for the given channel.
* The channel must be idle when this is called.
*/
static void ep93xx_dma_free_chan_resources(struct dma_chan *chan)
{
struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan);
struct ep93xx_dma_desc *desc, *d;
unsigned long flags;
LIST_HEAD(list);
BUG_ON(!list_empty(&edmac->active));
BUG_ON(!list_empty(&edmac->queue));
spin_lock_irqsave(&edmac->lock, flags);
edmac->edma->hw_shutdown(edmac);
edmac->runtime_addr = 0;
edmac->runtime_ctrl = 0;
edmac->buffer = 0;
list_splice_init(&edmac->free_list, &list);
spin_unlock_irqrestore(&edmac->lock, flags);
list_for_each_entry_safe(desc, d, &list, node)
kfree(desc);
clk_disable(edmac->clk);
free_irq(edmac->irq, edmac);
}
/**
* ep93xx_dma_prep_dma_memcpy - prepare a memcpy DMA operation
* @chan: channel
* @dest: destination bus address
* @src: source bus address
* @len: size of the transaction
* @flags: flags for the descriptor
*
* Returns a valid DMA descriptor or %NULL in case of failure.
*/
static struct dma_async_tx_descriptor *
ep93xx_dma_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest,
dma_addr_t src, size_t len, unsigned long flags)
{
struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan);
struct ep93xx_dma_desc *desc, *first;
size_t bytes, offset;
first = NULL;
for (offset = 0; offset < len; offset += bytes) {
desc = ep93xx_dma_desc_get(edmac);
if (!desc) {
dev_warn(chan2dev(edmac), "couldn't get descriptor\n");
goto fail;
}
bytes = min_t(size_t, len - offset, DMA_MAX_CHAN_BYTES);
desc->src_addr = src + offset;
desc->dst_addr = dest + offset;
desc->size = bytes;
if (!first)
first = desc;
else
list_add_tail(&desc->node, &first->tx_list);
}
first->txd.cookie = -EBUSY;
first->txd.flags = flags;
return &first->txd;
fail:
ep93xx_dma_desc_put(edmac, first);
return NULL;
}
/**
* ep93xx_dma_prep_slave_sg - prepare a slave DMA operation
* @chan: channel
* @sgl: list of buffers to transfer
* @sg_len: number of entries in @sgl
* @dir: direction of the DMA transfer
* @flags: flags for the descriptor
* @context: operation context (ignored)
*
* Returns a valid DMA descriptor or %NULL in case of failure.
*/
static struct dma_async_tx_descriptor *
ep93xx_dma_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 ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan);
struct ep93xx_dma_desc *desc, *first;
struct scatterlist *sg;
int i;
if (!edmac->edma->m2m && dir != ep93xx_dma_chan_direction(chan)) {
dev_warn(chan2dev(edmac),
"channel was configured with different direction\n");
return NULL;
}
if (test_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags)) {
dev_warn(chan2dev(edmac),
"channel is already used for cyclic transfers\n");
return NULL;
}
ep93xx_dma_slave_config_write(chan, dir, &edmac->slave_config);
first = NULL;
for_each_sg(sgl, sg, sg_len, i) {
size_t len = sg_dma_len(sg);
if (len > DMA_MAX_CHAN_BYTES) {
dev_warn(chan2dev(edmac), "too big transfer size %zu\n",
len);
goto fail;
}
desc = ep93xx_dma_desc_get(edmac);
if (!desc) {
dev_warn(chan2dev(edmac), "couldn't get descriptor\n");
goto fail;
}
if (dir == DMA_MEM_TO_DEV) {
desc->src_addr = sg_dma_address(sg);
desc->dst_addr = edmac->runtime_addr;
} else {
desc->src_addr = edmac->runtime_addr;
desc->dst_addr = sg_dma_address(sg);
}
desc->size = len;
if (!first)
first = desc;
else
list_add_tail(&desc->node, &first->tx_list);
}
first->txd.cookie = -EBUSY;
first->txd.flags = flags;
return &first->txd;
fail:
ep93xx_dma_desc_put(edmac, first);
return NULL;
}
/**
* ep93xx_dma_prep_dma_cyclic - prepare a cyclic DMA operation
* @chan: channel
* @dma_addr: DMA mapped address of the buffer
* @buf_len: length of the buffer (in bytes)
* @period_len: length of a single period
* @dir: direction of the operation
* @flags: tx descriptor status flags
*
* Prepares a descriptor for cyclic DMA operation. This means that once the
* descriptor is submitted, we will be submitting in a @period_len sized
* buffers and calling callback once the period has been elapsed. Transfer
* terminates only when client calls dmaengine_terminate_all() for this
* channel.
*
* Returns a valid DMA descriptor or %NULL in case of failure.
*/
static struct dma_async_tx_descriptor *
ep93xx_dma_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t dma_addr,
size_t buf_len, size_t period_len,
enum dma_transfer_direction dir, unsigned long flags)
{
struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan);
struct ep93xx_dma_desc *desc, *first;
size_t offset = 0;
if (!edmac->edma->m2m && dir != ep93xx_dma_chan_direction(chan)) {
dev_warn(chan2dev(edmac),
"channel was configured with different direction\n");
return NULL;
}
if (test_and_set_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags)) {
dev_warn(chan2dev(edmac),
"channel is already used for cyclic transfers\n");
return NULL;
}
if (period_len > DMA_MAX_CHAN_BYTES) {
dev_warn(chan2dev(edmac), "too big period length %zu\n",
period_len);
return NULL;
}
ep93xx_dma_slave_config_write(chan, dir, &edmac->slave_config);
/* Split the buffer into period size chunks */
first = NULL;
for (offset = 0; offset < buf_len; offset += period_len) {
desc = ep93xx_dma_desc_get(edmac);
if (!desc) {
dev_warn(chan2dev(edmac), "couldn't get descriptor\n");
goto fail;
}
if (dir == DMA_MEM_TO_DEV) {
desc->src_addr = dma_addr + offset;
desc->dst_addr = edmac->runtime_addr;
} else {
desc->src_addr = edmac->runtime_addr;
desc->dst_addr = dma_addr + offset;
}
desc->size = period_len;
if (!first)
first = desc;
else
list_add_tail(&desc->node, &first->tx_list);
}
first->txd.cookie = -EBUSY;
return &first->txd;
fail:
ep93xx_dma_desc_put(edmac, first);
return NULL;
}
/**
* ep93xx_dma_synchronize - Synchronizes the termination of transfers to the
* current context.
* @chan: channel
*
* Synchronizes the DMA channel termination to the current context. When this
* function returns it is guaranteed that all transfers for previously issued
* descriptors have stopped and and it is safe to free the memory associated
* with them. Furthermore it is guaranteed that all complete callback functions
* for a previously submitted descriptor have finished running and it is safe to
* free resources accessed from within the complete callbacks.
*/
static void ep93xx_dma_synchronize(struct dma_chan *chan)
{
struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan);
if (edmac->edma->hw_synchronize)
edmac->edma->hw_synchronize(edmac);
}
/**
* ep93xx_dma_terminate_all - terminate all transactions
* @chan: channel
*
* Stops all DMA transactions. All descriptors are put back to the
* @edmac->free_list and callbacks are _not_ called.
*/
static int ep93xx_dma_terminate_all(struct dma_chan *chan)
{
struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan);
struct ep93xx_dma_desc *desc, *_d;
unsigned long flags;
LIST_HEAD(list);
spin_lock_irqsave(&edmac->lock, flags);
/* First we disable and flush the DMA channel */
edmac->edma->hw_shutdown(edmac);
clear_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags);
list_splice_init(&edmac->active, &list);
list_splice_init(&edmac->queue, &list);
/*
* We then re-enable the channel. This way we can continue submitting
* the descriptors by just calling ->hw_submit() again.
*/
edmac->edma->hw_setup(edmac);
spin_unlock_irqrestore(&edmac->lock, flags);
list_for_each_entry_safe(desc, _d, &list, node)
ep93xx_dma_desc_put(edmac, desc);
return 0;
}
static int ep93xx_dma_slave_config(struct dma_chan *chan,
struct dma_slave_config *config)
{
struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan);
memcpy(&edmac->slave_config, config, sizeof(*config));
return 0;
}
static int ep93xx_dma_slave_config_write(struct dma_chan *chan,
enum dma_transfer_direction dir,
struct dma_slave_config *config)
{
struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan);
enum dma_slave_buswidth width;
unsigned long flags;
u32 addr, ctrl;
if (!edmac->edma->m2m)
return -EINVAL;
switch (dir) {
case DMA_DEV_TO_MEM:
width = config->src_addr_width;
addr = config->src_addr;
break;
case DMA_MEM_TO_DEV:
width = config->dst_addr_width;
addr = config->dst_addr;
break;
default:
return -EINVAL;
}
switch (width) {
case DMA_SLAVE_BUSWIDTH_1_BYTE:
ctrl = 0;
break;
case DMA_SLAVE_BUSWIDTH_2_BYTES:
ctrl = M2M_CONTROL_PW_16;
break;
case DMA_SLAVE_BUSWIDTH_4_BYTES:
ctrl = M2M_CONTROL_PW_32;
break;
default:
return -EINVAL;
}
spin_lock_irqsave(&edmac->lock, flags);
edmac->runtime_addr = addr;
edmac->runtime_ctrl = ctrl;
spin_unlock_irqrestore(&edmac->lock, flags);
return 0;
}
/**
* ep93xx_dma_tx_status - check if a transaction is completed
* @chan: channel
* @cookie: transaction specific cookie
* @state: state of the transaction is stored here if given
*
* This function can be used to query state of a given transaction.
*/
static enum dma_status ep93xx_dma_tx_status(struct dma_chan *chan,
dma_cookie_t cookie,
struct dma_tx_state *state)
{
return dma_cookie_status(chan, cookie, state);
}
/**
* ep93xx_dma_issue_pending - push pending transactions to the hardware
* @chan: channel
*
* When this function is called, all pending transactions are pushed to the
* hardware and executed.
*/
static void ep93xx_dma_issue_pending(struct dma_chan *chan)
{
ep93xx_dma_advance_work(to_ep93xx_dma_chan(chan));
}
static int __init ep93xx_dma_probe(struct platform_device *pdev)
{
struct ep93xx_dma_platform_data *pdata = dev_get_platdata(&pdev->dev);
struct ep93xx_dma_engine *edma;
struct dma_device *dma_dev;
size_t edma_size;
int ret, i;
edma_size = pdata->num_channels * sizeof(struct ep93xx_dma_chan);
edma = kzalloc(sizeof(*edma) + edma_size, GFP_KERNEL);
if (!edma)
return -ENOMEM;
dma_dev = &edma->dma_dev;
edma->m2m = platform_get_device_id(pdev)->driver_data;
edma->num_channels = pdata->num_channels;
INIT_LIST_HEAD(&dma_dev->channels);
for (i = 0; i < pdata->num_channels; i++) {
const struct ep93xx_dma_chan_data *cdata = &pdata->channels[i];
struct ep93xx_dma_chan *edmac = &edma->channels[i];
edmac->chan.device = dma_dev;
edmac->regs = cdata->base;
edmac->irq = cdata->irq;
edmac->edma = edma;
edmac->clk = clk_get(NULL, cdata->name);
if (IS_ERR(edmac->clk)) {
dev_warn(&pdev->dev, "failed to get clock for %s\n",
cdata->name);
continue;
}
spin_lock_init(&edmac->lock);
INIT_LIST_HEAD(&edmac->active);
INIT_LIST_HEAD(&edmac->queue);
INIT_LIST_HEAD(&edmac->free_list);
tasklet_setup(&edmac->tasklet, ep93xx_dma_tasklet);
list_add_tail(&edmac->chan.device_node,
&dma_dev->channels);
}
dma_cap_zero(dma_dev->cap_mask);
dma_cap_set(DMA_SLAVE, dma_dev->cap_mask);
dma_cap_set(DMA_CYCLIC, dma_dev->cap_mask);
dma_dev->dev = &pdev->dev;
dma_dev->device_alloc_chan_resources = ep93xx_dma_alloc_chan_resources;
dma_dev->device_free_chan_resources = ep93xx_dma_free_chan_resources;
dma_dev->device_prep_slave_sg = ep93xx_dma_prep_slave_sg;
dma_dev->device_prep_dma_cyclic = ep93xx_dma_prep_dma_cyclic;
dma_dev->device_config = ep93xx_dma_slave_config;
dma_dev->device_synchronize = ep93xx_dma_synchronize;
dma_dev->device_terminate_all = ep93xx_dma_terminate_all;
dma_dev->device_issue_pending = ep93xx_dma_issue_pending;
dma_dev->device_tx_status = ep93xx_dma_tx_status;
dma_set_max_seg_size(dma_dev->dev, DMA_MAX_CHAN_BYTES);
if (edma->m2m) {
dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask);
dma_dev->device_prep_dma_memcpy = ep93xx_dma_prep_dma_memcpy;
edma->hw_setup = m2m_hw_setup;
edma->hw_shutdown = m2m_hw_shutdown;
edma->hw_submit = m2m_hw_submit;
edma->hw_interrupt = m2m_hw_interrupt;
} else {
dma_cap_set(DMA_PRIVATE, dma_dev->cap_mask);
edma->hw_synchronize = m2p_hw_synchronize;
edma->hw_setup = m2p_hw_setup;
edma->hw_shutdown = m2p_hw_shutdown;
edma->hw_submit = m2p_hw_submit;
edma->hw_interrupt = m2p_hw_interrupt;
}
ret = dma_async_device_register(dma_dev);
if (unlikely(ret)) {
for (i = 0; i < edma->num_channels; i++) {
struct ep93xx_dma_chan *edmac = &edma->channels[i];
if (!IS_ERR_OR_NULL(edmac->clk))
clk_put(edmac->clk);
}
kfree(edma);
} else {
dev_info(dma_dev->dev, "EP93xx M2%s DMA ready\n",
edma->m2m ? "M" : "P");
}
return ret;
}
static const struct platform_device_id ep93xx_dma_driver_ids[] = {
{ "ep93xx-dma-m2p", 0 },
{ "ep93xx-dma-m2m", 1 },
{ },
};
static struct platform_driver ep93xx_dma_driver = {
.driver = {
.name = "ep93xx-dma",
},
.id_table = ep93xx_dma_driver_ids,
};
static int __init ep93xx_dma_module_init(void)
{
return platform_driver_probe(&ep93xx_dma_driver, ep93xx_dma_probe);
}
subsys_initcall(ep93xx_dma_module_init);
MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
MODULE_DESCRIPTION("EP93xx DMA driver");
MODULE_LICENSE("GPL");
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