linux/drivers/dma/ep93xx_dma.c
Alexander Sverdlin 94901e1b24 dmaengine: ep93xx: Treat STALL and NFB IRQs same way
Debugging ALSA hangups it was found that EP9302 (latest E2 rev.) DMA controller
sometimes asserts STALL interrupt instead of NFB interrupt. Simply ignoring the
difference and simply acting upon the amount of data we still have to transfer
seems to work fine. This somehow sounds similar to M2M issue which is already
dealt with in the driver, when the controller asserts DONE interrupt too early.

The issue is not documented in Cirrus Logic erratas for EP93XX, but original
Cirrus DMA driver from 2003 (not based on DMA API) did the similar handling
of STALL interrupt. In-tree driver (6d831c65) did it also, before conversion to
DMA engine API.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2016-01-25 09:49:55 +05:30

1391 lines
37 KiB
C

/*
* 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.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/clk.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/dmaengine.h>
#include <linux/module.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;
/**
* 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.
*
* 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 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_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_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)
{
if (list_empty(&edmac->active))
return NULL;
return list_first_entry(&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);
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_shutdown(struct ep93xx_dma_chan *edmac)
{
u32 control;
control = readl(edmac->regs + M2P_CONTROL);
control &= ~(M2P_CONTROL_STALLINT | M2P_CONTROL_NFBINT);
m2p_set_control(edmac, control);
while (m2p_channel_state(edmac) >= M2P_STATE_ON)
cpu_relax();
m2p_set_control(edmac, 0);
while (m2p_channel_state(edmac) == M2P_STATE_STALL)
cpu_relax();
}
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(unsigned long data)
{
struct ep93xx_dma_chan *edmac = (struct ep93xx_dma_chan *)data;
struct ep93xx_dma_desc *desc, *d;
dma_async_tx_callback callback = NULL;
void *callback_param = NULL;
LIST_HEAD(list);
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);
}
callback = desc->txd.callback;
callback_param = desc->txd.callback_param;
}
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);
}
if (callback)
callback(callback_param);
}
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 prosessed, 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), "couln'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 tha 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;
}
first = NULL;
for_each_sg(sgl, sg, sg_len, i) {
size_t sg_len = sg_dma_len(sg);
if (sg_len > DMA_MAX_CHAN_BYTES) {
dev_warn(chan2dev(edmac), "too big transfer size %d\n",
sg_len);
goto fail;
}
desc = ep93xx_dma_desc_get(edmac);
if (!desc) {
dev_warn(chan2dev(edmac), "couln'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 = sg_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 %d\n",
period_len);
return NULL;
}
/* 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), "couln'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_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);
enum dma_slave_buswidth width;
unsigned long flags;
u32 addr, ctrl;
if (!edmac->edma->m2m)
return -EINVAL;
switch (config->direction) {
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_init(&edmac->tasklet, ep93xx_dma_tasklet,
(unsigned long)edmac);
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_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_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");