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linux/drivers/dma/sun4i-dma.c

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/*
* Copyright (C) 2014 Emilio López
* Emilio López <emilio@elopez.com.ar>
*
* 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/bitmap.h>
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/dmaengine.h>
#include <linux/dmapool.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of_dma.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include "virt-dma.h"
/** Common macros to normal and dedicated DMA registers **/
#define SUN4I_DMA_CFG_LOADING BIT(31)
#define SUN4I_DMA_CFG_DST_DATA_WIDTH(width) ((width) << 25)
#define SUN4I_DMA_CFG_DST_BURST_LENGTH(len) ((len) << 23)
#define SUN4I_DMA_CFG_DST_ADDR_MODE(mode) ((mode) << 21)
#define SUN4I_DMA_CFG_DST_DRQ_TYPE(type) ((type) << 16)
#define SUN4I_DMA_CFG_SRC_DATA_WIDTH(width) ((width) << 9)
#define SUN4I_DMA_CFG_SRC_BURST_LENGTH(len) ((len) << 7)
#define SUN4I_DMA_CFG_SRC_ADDR_MODE(mode) ((mode) << 5)
#define SUN4I_DMA_CFG_SRC_DRQ_TYPE(type) (type)
/** Normal DMA register values **/
/* Normal DMA source/destination data request type values */
#define SUN4I_NDMA_DRQ_TYPE_SDRAM 0x16
#define SUN4I_NDMA_DRQ_TYPE_LIMIT (0x1F + 1)
/** Normal DMA register layout **/
/* Dedicated DMA source/destination address mode values */
#define SUN4I_NDMA_ADDR_MODE_LINEAR 0
#define SUN4I_NDMA_ADDR_MODE_IO 1
/* Normal DMA configuration register layout */
#define SUN4I_NDMA_CFG_CONT_MODE BIT(30)
#define SUN4I_NDMA_CFG_WAIT_STATE(n) ((n) << 27)
#define SUN4I_NDMA_CFG_DST_NON_SECURE BIT(22)
#define SUN4I_NDMA_CFG_BYTE_COUNT_MODE_REMAIN BIT(15)
#define SUN4I_NDMA_CFG_SRC_NON_SECURE BIT(6)
/** Dedicated DMA register values **/
/* Dedicated DMA source/destination address mode values */
#define SUN4I_DDMA_ADDR_MODE_LINEAR 0
#define SUN4I_DDMA_ADDR_MODE_IO 1
#define SUN4I_DDMA_ADDR_MODE_HORIZONTAL_PAGE 2
#define SUN4I_DDMA_ADDR_MODE_VERTICAL_PAGE 3
/* Dedicated DMA source/destination data request type values */
#define SUN4I_DDMA_DRQ_TYPE_SDRAM 0x1
#define SUN4I_DDMA_DRQ_TYPE_LIMIT (0x1F + 1)
/** Dedicated DMA register layout **/
/* Dedicated DMA configuration register layout */
#define SUN4I_DDMA_CFG_BUSY BIT(30)
#define SUN4I_DDMA_CFG_CONT_MODE BIT(29)
#define SUN4I_DDMA_CFG_DST_NON_SECURE BIT(28)
#define SUN4I_DDMA_CFG_BYTE_COUNT_MODE_REMAIN BIT(15)
#define SUN4I_DDMA_CFG_SRC_NON_SECURE BIT(12)
/* Dedicated DMA parameter register layout */
#define SUN4I_DDMA_PARA_DST_DATA_BLK_SIZE(n) (((n) - 1) << 24)
#define SUN4I_DDMA_PARA_DST_WAIT_CYCLES(n) (((n) - 1) << 16)
#define SUN4I_DDMA_PARA_SRC_DATA_BLK_SIZE(n) (((n) - 1) << 8)
#define SUN4I_DDMA_PARA_SRC_WAIT_CYCLES(n) (((n) - 1) << 0)
/** DMA register offsets **/
/* General register offsets */
#define SUN4I_DMA_IRQ_ENABLE_REG 0x0
#define SUN4I_DMA_IRQ_PENDING_STATUS_REG 0x4
/* Normal DMA register offsets */
#define SUN4I_NDMA_CHANNEL_REG_BASE(n) (0x100 + (n) * 0x20)
#define SUN4I_NDMA_CFG_REG 0x0
#define SUN4I_NDMA_SRC_ADDR_REG 0x4
#define SUN4I_NDMA_DST_ADDR_REG 0x8
#define SUN4I_NDMA_BYTE_COUNT_REG 0xC
/* Dedicated DMA register offsets */
#define SUN4I_DDMA_CHANNEL_REG_BASE(n) (0x300 + (n) * 0x20)
#define SUN4I_DDMA_CFG_REG 0x0
#define SUN4I_DDMA_SRC_ADDR_REG 0x4
#define SUN4I_DDMA_DST_ADDR_REG 0x8
#define SUN4I_DDMA_BYTE_COUNT_REG 0xC
#define SUN4I_DDMA_PARA_REG 0x18
/** DMA Driver **/
/*
* Normal DMA has 8 channels, and Dedicated DMA has another 8, so
* that's 16 channels. As for endpoints, there's 29 and 21
* respectively. Given that the Normal DMA endpoints (other than
* SDRAM) can be used as tx/rx, we need 78 vchans in total
*/
#define SUN4I_NDMA_NR_MAX_CHANNELS 8
#define SUN4I_DDMA_NR_MAX_CHANNELS 8
#define SUN4I_DMA_NR_MAX_CHANNELS \
(SUN4I_NDMA_NR_MAX_CHANNELS + SUN4I_DDMA_NR_MAX_CHANNELS)
#define SUN4I_NDMA_NR_MAX_VCHANS (29 * 2 - 1)
#define SUN4I_DDMA_NR_MAX_VCHANS 21
#define SUN4I_DMA_NR_MAX_VCHANS \
(SUN4I_NDMA_NR_MAX_VCHANS + SUN4I_DDMA_NR_MAX_VCHANS)
/* This set of SUN4I_DDMA timing parameters were found experimentally while
* working with the SPI driver and seem to make it behave correctly */
#define SUN4I_DDMA_MAGIC_SPI_PARAMETERS \
(SUN4I_DDMA_PARA_DST_DATA_BLK_SIZE(1) | \
SUN4I_DDMA_PARA_SRC_DATA_BLK_SIZE(1) | \
SUN4I_DDMA_PARA_DST_WAIT_CYCLES(2) | \
SUN4I_DDMA_PARA_SRC_WAIT_CYCLES(2))
struct sun4i_dma_pchan {
/* Register base of channel */
void __iomem *base;
/* vchan currently being serviced */
struct sun4i_dma_vchan *vchan;
/* Is this a dedicated pchan? */
int is_dedicated;
};
struct sun4i_dma_vchan {
struct virt_dma_chan vc;
struct dma_slave_config cfg;
struct sun4i_dma_pchan *pchan;
struct sun4i_dma_promise *processing;
struct sun4i_dma_contract *contract;
u8 endpoint;
int is_dedicated;
};
struct sun4i_dma_promise {
u32 cfg;
u32 para;
dma_addr_t src;
dma_addr_t dst;
size_t len;
struct list_head list;
};
/* A contract is a set of promises */
struct sun4i_dma_contract {
struct virt_dma_desc vd;
struct list_head demands;
struct list_head completed_demands;
int is_cyclic;
};
struct sun4i_dma_dev {
DECLARE_BITMAP(pchans_used, SUN4I_DMA_NR_MAX_CHANNELS);
struct dma_device slave;
struct sun4i_dma_pchan *pchans;
struct sun4i_dma_vchan *vchans;
void __iomem *base;
struct clk *clk;
int irq;
spinlock_t lock;
};
static struct sun4i_dma_dev *to_sun4i_dma_dev(struct dma_device *dev)
{
return container_of(dev, struct sun4i_dma_dev, slave);
}
static struct sun4i_dma_vchan *to_sun4i_dma_vchan(struct dma_chan *chan)
{
return container_of(chan, struct sun4i_dma_vchan, vc.chan);
}
static struct sun4i_dma_contract *to_sun4i_dma_contract(struct virt_dma_desc *vd)
{
return container_of(vd, struct sun4i_dma_contract, vd);
}
static struct device *chan2dev(struct dma_chan *chan)
{
return &chan->dev->device;
}
static int convert_burst(u32 maxburst)
{
if (maxburst > 8)
return -EINVAL;
/* 1 -> 0, 4 -> 1, 8 -> 2 */
return (maxburst >> 2);
}
static int convert_buswidth(enum dma_slave_buswidth addr_width)
{
if (addr_width > DMA_SLAVE_BUSWIDTH_4_BYTES)
return -EINVAL;
/* 8 (1 byte) -> 0, 16 (2 bytes) -> 1, 32 (4 bytes) -> 2 */
return (addr_width >> 1);
}
static void sun4i_dma_free_chan_resources(struct dma_chan *chan)
{
struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
vchan_free_chan_resources(&vchan->vc);
}
static struct sun4i_dma_pchan *find_and_use_pchan(struct sun4i_dma_dev *priv,
struct sun4i_dma_vchan *vchan)
{
struct sun4i_dma_pchan *pchan = NULL, *pchans = priv->pchans;
unsigned long flags;
int i, max;
/*
* pchans 0-SUN4I_NDMA_NR_MAX_CHANNELS are normal, and
* SUN4I_NDMA_NR_MAX_CHANNELS+ are dedicated ones
*/
if (vchan->is_dedicated) {
i = SUN4I_NDMA_NR_MAX_CHANNELS;
max = SUN4I_DMA_NR_MAX_CHANNELS;
} else {
i = 0;
max = SUN4I_NDMA_NR_MAX_CHANNELS;
}
spin_lock_irqsave(&priv->lock, flags);
for_each_clear_bit_from(i, priv->pchans_used, max) {
pchan = &pchans[i];
pchan->vchan = vchan;
set_bit(i, priv->pchans_used);
break;
}
spin_unlock_irqrestore(&priv->lock, flags);
return pchan;
}
static void release_pchan(struct sun4i_dma_dev *priv,
struct sun4i_dma_pchan *pchan)
{
unsigned long flags;
int nr = pchan - priv->pchans;
spin_lock_irqsave(&priv->lock, flags);
pchan->vchan = NULL;
clear_bit(nr, priv->pchans_used);
spin_unlock_irqrestore(&priv->lock, flags);
}
static void configure_pchan(struct sun4i_dma_pchan *pchan,
struct sun4i_dma_promise *d)
{
/*
* Configure addresses and misc parameters depending on type
* SUN4I_DDMA has an extra field with timing parameters
*/
if (pchan->is_dedicated) {
writel_relaxed(d->src, pchan->base + SUN4I_DDMA_SRC_ADDR_REG);
writel_relaxed(d->dst, pchan->base + SUN4I_DDMA_DST_ADDR_REG);
writel_relaxed(d->len, pchan->base + SUN4I_DDMA_BYTE_COUNT_REG);
writel_relaxed(d->para, pchan->base + SUN4I_DDMA_PARA_REG);
writel_relaxed(d->cfg, pchan->base + SUN4I_DDMA_CFG_REG);
} else {
writel_relaxed(d->src, pchan->base + SUN4I_NDMA_SRC_ADDR_REG);
writel_relaxed(d->dst, pchan->base + SUN4I_NDMA_DST_ADDR_REG);
writel_relaxed(d->len, pchan->base + SUN4I_NDMA_BYTE_COUNT_REG);
writel_relaxed(d->cfg, pchan->base + SUN4I_NDMA_CFG_REG);
}
}
static void set_pchan_interrupt(struct sun4i_dma_dev *priv,
struct sun4i_dma_pchan *pchan,
int half, int end)
{
u32 reg;
int pchan_number = pchan - priv->pchans;
unsigned long flags;
spin_lock_irqsave(&priv->lock, flags);
reg = readl_relaxed(priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
if (half)
reg |= BIT(pchan_number * 2);
else
reg &= ~BIT(pchan_number * 2);
if (end)
reg |= BIT(pchan_number * 2 + 1);
else
reg &= ~BIT(pchan_number * 2 + 1);
writel_relaxed(reg, priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
spin_unlock_irqrestore(&priv->lock, flags);
}
/**
* Execute pending operations on a vchan
*
* When given a vchan, this function will try to acquire a suitable
* pchan and, if successful, will configure it to fulfill a promise
* from the next pending contract.
*
* This function must be called with &vchan->vc.lock held.
*/
static int __execute_vchan_pending(struct sun4i_dma_dev *priv,
struct sun4i_dma_vchan *vchan)
{
struct sun4i_dma_promise *promise = NULL;
struct sun4i_dma_contract *contract = NULL;
struct sun4i_dma_pchan *pchan;
struct virt_dma_desc *vd;
int ret;
lockdep_assert_held(&vchan->vc.lock);
/* We need a pchan to do anything, so secure one if available */
pchan = find_and_use_pchan(priv, vchan);
if (!pchan)
return -EBUSY;
/*
* Channel endpoints must not be repeated, so if this vchan
* has already submitted some work, we can't do anything else
*/
if (vchan->processing) {
dev_dbg(chan2dev(&vchan->vc.chan),
"processing something to this endpoint already\n");
ret = -EBUSY;
goto release_pchan;
}
do {
/* Figure out which contract we're working with today */
vd = vchan_next_desc(&vchan->vc);
if (!vd) {
dev_dbg(chan2dev(&vchan->vc.chan),
"No pending contract found");
ret = 0;
goto release_pchan;
}
contract = to_sun4i_dma_contract(vd);
if (list_empty(&contract->demands)) {
/* The contract has been completed so mark it as such */
list_del(&contract->vd.node);
vchan_cookie_complete(&contract->vd);
dev_dbg(chan2dev(&vchan->vc.chan),
"Empty contract found and marked complete");
}
} while (list_empty(&contract->demands));
/* Now find out what we need to do */
promise = list_first_entry(&contract->demands,
struct sun4i_dma_promise, list);
vchan->processing = promise;
/* ... and make it reality */
if (promise) {
vchan->contract = contract;
vchan->pchan = pchan;
set_pchan_interrupt(priv, pchan, contract->is_cyclic, 1);
configure_pchan(pchan, promise);
}
return 0;
release_pchan:
release_pchan(priv, pchan);
return ret;
}
static int sanitize_config(struct dma_slave_config *sconfig,
enum dma_transfer_direction direction)
{
switch (direction) {
case DMA_MEM_TO_DEV:
if ((sconfig->dst_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) ||
!sconfig->dst_maxburst)
return -EINVAL;
if (sconfig->src_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED)
sconfig->src_addr_width = sconfig->dst_addr_width;
if (!sconfig->src_maxburst)
sconfig->src_maxburst = sconfig->dst_maxburst;
break;
case DMA_DEV_TO_MEM:
if ((sconfig->src_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) ||
!sconfig->src_maxburst)
return -EINVAL;
if (sconfig->dst_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED)
sconfig->dst_addr_width = sconfig->src_addr_width;
if (!sconfig->dst_maxburst)
sconfig->dst_maxburst = sconfig->src_maxburst;
break;
default:
return 0;
}
return 0;
}
/**
* Generate a promise, to be used in a normal DMA contract.
*
* A NDMA promise contains all the information required to program the
* normal part of the DMA Engine and get data copied. A non-executed
* promise will live in the demands list on a contract. Once it has been
* completed, it will be moved to the completed demands list for later freeing.
* All linked promises will be freed when the corresponding contract is freed
*/
static struct sun4i_dma_promise *
generate_ndma_promise(struct dma_chan *chan, dma_addr_t src, dma_addr_t dest,
size_t len, struct dma_slave_config *sconfig,
enum dma_transfer_direction direction)
{
struct sun4i_dma_promise *promise;
int ret;
ret = sanitize_config(sconfig, direction);
if (ret)
return NULL;
promise = kzalloc(sizeof(*promise), GFP_NOWAIT);
if (!promise)
return NULL;
promise->src = src;
promise->dst = dest;
promise->len = len;
promise->cfg = SUN4I_DMA_CFG_LOADING |
SUN4I_NDMA_CFG_BYTE_COUNT_MODE_REMAIN;
dev_dbg(chan2dev(chan),
"src burst %d, dst burst %d, src buswidth %d, dst buswidth %d",
sconfig->src_maxburst, sconfig->dst_maxburst,
sconfig->src_addr_width, sconfig->dst_addr_width);
/* Source burst */
ret = convert_burst(sconfig->src_maxburst);
if (ret < 0)
goto fail;
promise->cfg |= SUN4I_DMA_CFG_SRC_BURST_LENGTH(ret);
/* Destination burst */
ret = convert_burst(sconfig->dst_maxburst);
if (ret < 0)
goto fail;
promise->cfg |= SUN4I_DMA_CFG_DST_BURST_LENGTH(ret);
/* Source bus width */
ret = convert_buswidth(sconfig->src_addr_width);
if (ret < 0)
goto fail;
promise->cfg |= SUN4I_DMA_CFG_SRC_DATA_WIDTH(ret);
/* Destination bus width */
ret = convert_buswidth(sconfig->dst_addr_width);
if (ret < 0)
goto fail;
promise->cfg |= SUN4I_DMA_CFG_DST_DATA_WIDTH(ret);
return promise;
fail:
kfree(promise);
return NULL;
}
/**
* Generate a promise, to be used in a dedicated DMA contract.
*
* A DDMA promise contains all the information required to program the
* Dedicated part of the DMA Engine and get data copied. A non-executed
* promise will live in the demands list on a contract. Once it has been
* completed, it will be moved to the completed demands list for later freeing.
* All linked promises will be freed when the corresponding contract is freed
*/
static struct sun4i_dma_promise *
generate_ddma_promise(struct dma_chan *chan, dma_addr_t src, dma_addr_t dest,
size_t len, struct dma_slave_config *sconfig)
{
struct sun4i_dma_promise *promise;
int ret;
promise = kzalloc(sizeof(*promise), GFP_NOWAIT);
if (!promise)
return NULL;
promise->src = src;
promise->dst = dest;
promise->len = len;
promise->cfg = SUN4I_DMA_CFG_LOADING |
SUN4I_DDMA_CFG_BYTE_COUNT_MODE_REMAIN;
/* Source burst */
ret = convert_burst(sconfig->src_maxburst);
if (ret < 0)
goto fail;
promise->cfg |= SUN4I_DMA_CFG_SRC_BURST_LENGTH(ret);
/* Destination burst */
ret = convert_burst(sconfig->dst_maxburst);
if (ret < 0)
goto fail;
promise->cfg |= SUN4I_DMA_CFG_DST_BURST_LENGTH(ret);
/* Source bus width */
ret = convert_buswidth(sconfig->src_addr_width);
if (ret < 0)
goto fail;
promise->cfg |= SUN4I_DMA_CFG_SRC_DATA_WIDTH(ret);
/* Destination bus width */
ret = convert_buswidth(sconfig->dst_addr_width);
if (ret < 0)
goto fail;
promise->cfg |= SUN4I_DMA_CFG_DST_DATA_WIDTH(ret);
return promise;
fail:
kfree(promise);
return NULL;
}
/**
* Generate a contract
*
* Contracts function as DMA descriptors. As our hardware does not support
* linked lists, we need to implement SG via software. We use a contract
* to hold all the pieces of the request and process them serially one
* after another. Each piece is represented as a promise.
*/
static struct sun4i_dma_contract *generate_dma_contract(void)
{
struct sun4i_dma_contract *contract;
contract = kzalloc(sizeof(*contract), GFP_NOWAIT);
if (!contract)
return NULL;
INIT_LIST_HEAD(&contract->demands);
INIT_LIST_HEAD(&contract->completed_demands);
return contract;
}
/**
* Get next promise on a cyclic transfer
*
* Cyclic contracts contain a series of promises which are executed on a
* loop. This function returns the next promise from a cyclic contract,
* so it can be programmed into the hardware.
*/
static struct sun4i_dma_promise *
get_next_cyclic_promise(struct sun4i_dma_contract *contract)
{
struct sun4i_dma_promise *promise;
promise = list_first_entry_or_null(&contract->demands,
struct sun4i_dma_promise, list);
if (!promise) {
list_splice_init(&contract->completed_demands,
&contract->demands);
promise = list_first_entry(&contract->demands,
struct sun4i_dma_promise, list);
}
return promise;
}
/**
* Free a contract and all its associated promises
*/
static void sun4i_dma_free_contract(struct virt_dma_desc *vd)
{
struct sun4i_dma_contract *contract = to_sun4i_dma_contract(vd);
struct sun4i_dma_promise *promise, *tmp;
/* Free all the demands and completed demands */
list_for_each_entry_safe(promise, tmp, &contract->demands, list)
kfree(promise);
list_for_each_entry_safe(promise, tmp, &contract->completed_demands, list)
kfree(promise);
kfree(contract);
}
static struct dma_async_tx_descriptor *
sun4i_dma_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest,
dma_addr_t src, size_t len, unsigned long flags)
{
struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
struct dma_slave_config *sconfig = &vchan->cfg;
struct sun4i_dma_promise *promise;
struct sun4i_dma_contract *contract;
contract = generate_dma_contract();
if (!contract)
return NULL;
/*
* We can only do the copy to bus aligned addresses, so
* choose the best one so we get decent performance. We also
* maximize the burst size for this same reason.
*/
sconfig->src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
sconfig->dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
sconfig->src_maxburst = 8;
sconfig->dst_maxburst = 8;
if (vchan->is_dedicated)
promise = generate_ddma_promise(chan, src, dest, len, sconfig);
else
promise = generate_ndma_promise(chan, src, dest, len, sconfig,
DMA_MEM_TO_MEM);
if (!promise) {
kfree(contract);
return NULL;
}
/* Configure memcpy mode */
if (vchan->is_dedicated) {
promise->cfg |= SUN4I_DMA_CFG_SRC_DRQ_TYPE(SUN4I_DDMA_DRQ_TYPE_SDRAM) |
SUN4I_DMA_CFG_DST_DRQ_TYPE(SUN4I_DDMA_DRQ_TYPE_SDRAM);
} else {
promise->cfg |= SUN4I_DMA_CFG_SRC_DRQ_TYPE(SUN4I_NDMA_DRQ_TYPE_SDRAM) |
SUN4I_DMA_CFG_DST_DRQ_TYPE(SUN4I_NDMA_DRQ_TYPE_SDRAM);
}
/* Fill the contract with our only promise */
list_add_tail(&promise->list, &contract->demands);
/* And add it to the vchan */
return vchan_tx_prep(&vchan->vc, &contract->vd, flags);
}
static struct dma_async_tx_descriptor *
sun4i_dma_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf, size_t len,
size_t period_len, enum dma_transfer_direction dir,
unsigned long flags)
{
struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
struct dma_slave_config *sconfig = &vchan->cfg;
struct sun4i_dma_promise *promise;
struct sun4i_dma_contract *contract;
dma_addr_t src, dest;
u32 endpoints;
int nr_periods, offset, plength, i;
if (!is_slave_direction(dir)) {
dev_err(chan2dev(chan), "Invalid DMA direction\n");
return NULL;
}
if (vchan->is_dedicated) {
/*
* As we are using this just for audio data, we need to use
* normal DMA. There is nothing stopping us from supporting
* dedicated DMA here as well, so if a client comes up and
* requires it, it will be simple to implement it.
*/
dev_err(chan2dev(chan),
"Cyclic transfers are only supported on Normal DMA\n");
return NULL;
}
contract = generate_dma_contract();
if (!contract)
return NULL;
contract->is_cyclic = 1;
/* Figure out the endpoints and the address we need */
if (dir == DMA_MEM_TO_DEV) {
src = buf;
dest = sconfig->dst_addr;
endpoints = SUN4I_DMA_CFG_SRC_DRQ_TYPE(SUN4I_NDMA_DRQ_TYPE_SDRAM) |
SUN4I_DMA_CFG_DST_DRQ_TYPE(vchan->endpoint) |
SUN4I_DMA_CFG_DST_ADDR_MODE(SUN4I_NDMA_ADDR_MODE_IO);
} else {
src = sconfig->src_addr;
dest = buf;
endpoints = SUN4I_DMA_CFG_SRC_DRQ_TYPE(vchan->endpoint) |
SUN4I_DMA_CFG_SRC_ADDR_MODE(SUN4I_NDMA_ADDR_MODE_IO) |
SUN4I_DMA_CFG_DST_DRQ_TYPE(SUN4I_NDMA_DRQ_TYPE_SDRAM);
}
/*
* We will be using half done interrupts to make two periods
* out of a promise, so we need to program the DMA engine less
* often
*/
/*
* The engine can interrupt on half-transfer, so we can use
* this feature to program the engine half as often as if we
* didn't use it (keep in mind the hardware doesn't support
* linked lists).
*
* Say you have a set of periods (| marks the start/end, I for
* interrupt, P for programming the engine to do a new
* transfer), the easy but slow way would be to do
*
* |---|---|---|---| (periods / promises)
* P I,P I,P I,P I
*
* Using half transfer interrupts you can do
*
* |-------|-------| (promises as configured on hw)
* |---|---|---|---| (periods)
* P I I,P I I
*
* Which requires half the engine programming for the same
* functionality.
*/
nr_periods = DIV_ROUND_UP(len / period_len, 2);
for (i = 0; i < nr_periods; i++) {
/* Calculate the offset in the buffer and the length needed */
offset = i * period_len * 2;
plength = min((len - offset), (period_len * 2));
if (dir == DMA_MEM_TO_DEV)
src = buf + offset;
else
dest = buf + offset;
/* Make the promise */
promise = generate_ndma_promise(chan, src, dest,
plength, sconfig, dir);
if (!promise) {
/* TODO: should we free everything? */
return NULL;
}
promise->cfg |= endpoints;
/* Then add it to the contract */
list_add_tail(&promise->list, &contract->demands);
}
/* And add it to the vchan */
return vchan_tx_prep(&vchan->vc, &contract->vd, flags);
}
static struct dma_async_tx_descriptor *
sun4i_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 sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
struct dma_slave_config *sconfig = &vchan->cfg;
struct sun4i_dma_promise *promise;
struct sun4i_dma_contract *contract;
u8 ram_type, io_mode, linear_mode;
struct scatterlist *sg;
dma_addr_t srcaddr, dstaddr;
u32 endpoints, para;
int i;
if (!sgl)
return NULL;
if (!is_slave_direction(dir)) {
dev_err(chan2dev(chan), "Invalid DMA direction\n");
return NULL;
}
contract = generate_dma_contract();
if (!contract)
return NULL;
if (vchan->is_dedicated) {
io_mode = SUN4I_DDMA_ADDR_MODE_IO;
linear_mode = SUN4I_DDMA_ADDR_MODE_LINEAR;
ram_type = SUN4I_DDMA_DRQ_TYPE_SDRAM;
} else {
io_mode = SUN4I_NDMA_ADDR_MODE_IO;
linear_mode = SUN4I_NDMA_ADDR_MODE_LINEAR;
ram_type = SUN4I_NDMA_DRQ_TYPE_SDRAM;
}
if (dir == DMA_MEM_TO_DEV)
endpoints = SUN4I_DMA_CFG_DST_DRQ_TYPE(vchan->endpoint) |
SUN4I_DMA_CFG_DST_ADDR_MODE(io_mode) |
SUN4I_DMA_CFG_SRC_DRQ_TYPE(ram_type) |
SUN4I_DMA_CFG_SRC_ADDR_MODE(linear_mode);
else
endpoints = SUN4I_DMA_CFG_DST_DRQ_TYPE(ram_type) |
SUN4I_DMA_CFG_DST_ADDR_MODE(linear_mode) |
SUN4I_DMA_CFG_SRC_DRQ_TYPE(vchan->endpoint) |
SUN4I_DMA_CFG_SRC_ADDR_MODE(io_mode);
for_each_sg(sgl, sg, sg_len, i) {
/* Figure out addresses */
if (dir == DMA_MEM_TO_DEV) {
srcaddr = sg_dma_address(sg);
dstaddr = sconfig->dst_addr;
} else {
srcaddr = sconfig->src_addr;
dstaddr = sg_dma_address(sg);
}
/*
* These are the magic DMA engine timings that keep SPI going.
* I haven't seen any interface on DMAEngine to configure
* timings, and so far they seem to work for everything we
* support, so I've kept them here. I don't know if other
* devices need different timings because, as usual, we only
* have the "para" bitfield meanings, but no comment on what
* the values should be when doing a certain operation :|
*/
para = SUN4I_DDMA_MAGIC_SPI_PARAMETERS;
/* And make a suitable promise */
if (vchan->is_dedicated)
promise = generate_ddma_promise(chan, srcaddr, dstaddr,
sg_dma_len(sg),
sconfig);
else
promise = generate_ndma_promise(chan, srcaddr, dstaddr,
sg_dma_len(sg),
sconfig, dir);
if (!promise)
return NULL; /* TODO: should we free everything? */
promise->cfg |= endpoints;
promise->para = para;
/* Then add it to the contract */
list_add_tail(&promise->list, &contract->demands);
}
/*
* Once we've got all the promises ready, add the contract
* to the pending list on the vchan
*/
return vchan_tx_prep(&vchan->vc, &contract->vd, flags);
}
static int sun4i_dma_terminate_all(struct dma_chan *chan)
{
struct sun4i_dma_dev *priv = to_sun4i_dma_dev(chan->device);
struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
struct sun4i_dma_pchan *pchan = vchan->pchan;
LIST_HEAD(head);
unsigned long flags;
spin_lock_irqsave(&vchan->vc.lock, flags);
vchan_get_all_descriptors(&vchan->vc, &head);
spin_unlock_irqrestore(&vchan->vc.lock, flags);
/*
* Clearing the configuration register will halt the pchan. Interrupts
* may still trigger, so don't forget to disable them.
*/
if (pchan) {
if (pchan->is_dedicated)
writel(0, pchan->base + SUN4I_DDMA_CFG_REG);
else
writel(0, pchan->base + SUN4I_NDMA_CFG_REG);
set_pchan_interrupt(priv, pchan, 0, 0);
release_pchan(priv, pchan);
}
spin_lock_irqsave(&vchan->vc.lock, flags);
vchan_dma_desc_free_list(&vchan->vc, &head);
/* Clear these so the vchan is usable again */
vchan->processing = NULL;
vchan->pchan = NULL;
spin_unlock_irqrestore(&vchan->vc.lock, flags);
return 0;
}
static int sun4i_dma_config(struct dma_chan *chan,
struct dma_slave_config *config)
{
struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
memcpy(&vchan->cfg, config, sizeof(*config));
return 0;
}
static struct dma_chan *sun4i_dma_of_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma)
{
struct sun4i_dma_dev *priv = ofdma->of_dma_data;
struct sun4i_dma_vchan *vchan;
struct dma_chan *chan;
u8 is_dedicated = dma_spec->args[0];
u8 endpoint = dma_spec->args[1];
/* Check if type is Normal or Dedicated */
if (is_dedicated != 0 && is_dedicated != 1)
return NULL;
/* Make sure the endpoint looks sane */
if ((is_dedicated && endpoint >= SUN4I_DDMA_DRQ_TYPE_LIMIT) ||
(!is_dedicated && endpoint >= SUN4I_NDMA_DRQ_TYPE_LIMIT))
return NULL;
chan = dma_get_any_slave_channel(&priv->slave);
if (!chan)
return NULL;
/* Assign the endpoint to the vchan */
vchan = to_sun4i_dma_vchan(chan);
vchan->is_dedicated = is_dedicated;
vchan->endpoint = endpoint;
return chan;
}
static enum dma_status sun4i_dma_tx_status(struct dma_chan *chan,
dma_cookie_t cookie,
struct dma_tx_state *state)
{
struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
struct sun4i_dma_pchan *pchan = vchan->pchan;
struct sun4i_dma_contract *contract;
struct sun4i_dma_promise *promise;
struct virt_dma_desc *vd;
unsigned long flags;
enum dma_status ret;
size_t bytes = 0;
ret = dma_cookie_status(chan, cookie, state);
if (!state || (ret == DMA_COMPLETE))
return ret;
spin_lock_irqsave(&vchan->vc.lock, flags);
vd = vchan_find_desc(&vchan->vc, cookie);
if (!vd)
goto exit;
contract = to_sun4i_dma_contract(vd);
list_for_each_entry(promise, &contract->demands, list)
bytes += promise->len;
/*
* The hardware is configured to return the remaining byte
* quantity. If possible, replace the first listed element's
* full size with the actual remaining amount
*/
promise = list_first_entry_or_null(&contract->demands,
struct sun4i_dma_promise, list);
if (promise && pchan) {
bytes -= promise->len;
if (pchan->is_dedicated)
bytes += readl(pchan->base + SUN4I_DDMA_BYTE_COUNT_REG);
else
bytes += readl(pchan->base + SUN4I_NDMA_BYTE_COUNT_REG);
}
exit:
dma_set_residue(state, bytes);
spin_unlock_irqrestore(&vchan->vc.lock, flags);
return ret;
}
static void sun4i_dma_issue_pending(struct dma_chan *chan)
{
struct sun4i_dma_dev *priv = to_sun4i_dma_dev(chan->device);
struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
unsigned long flags;
spin_lock_irqsave(&vchan->vc.lock, flags);
/*
* If there are pending transactions for this vchan, push one of
* them into the engine to get the ball rolling.
*/
if (vchan_issue_pending(&vchan->vc))
__execute_vchan_pending(priv, vchan);
spin_unlock_irqrestore(&vchan->vc.lock, flags);
}
static irqreturn_t sun4i_dma_interrupt(int irq, void *dev_id)
{
struct sun4i_dma_dev *priv = dev_id;
struct sun4i_dma_pchan *pchans = priv->pchans, *pchan;
struct sun4i_dma_vchan *vchan;
struct sun4i_dma_contract *contract;
struct sun4i_dma_promise *promise;
unsigned long pendirq, irqs, disableirqs;
int bit, i, free_room, allow_mitigation = 1;
pendirq = readl_relaxed(priv->base + SUN4I_DMA_IRQ_PENDING_STATUS_REG);
handle_pending:
disableirqs = 0;
free_room = 0;
for_each_set_bit(bit, &pendirq, 32) {
pchan = &pchans[bit >> 1];
vchan = pchan->vchan;
if (!vchan) /* a terminated channel may still interrupt */
continue;
contract = vchan->contract;
/*
* Disable the IRQ and free the pchan if it's an end
* interrupt (odd bit)
*/
if (bit & 1) {
spin_lock(&vchan->vc.lock);
/*
* Move the promise into the completed list now that
* we're done with it
*/
list_del(&vchan->processing->list);
list_add_tail(&vchan->processing->list,
&contract->completed_demands);
/*
* Cyclic DMA transfers are special:
* - There's always something we can dispatch
* - We need to run the callback
* - Latency is very important, as this is used by audio
* We therefore just cycle through the list and dispatch
* whatever we have here, reusing the pchan. There's
* no need to run the thread after this.
*
* For non-cyclic transfers we need to look around,
* so we can program some more work, or notify the
* client that their transfers have been completed.
*/
if (contract->is_cyclic) {
promise = get_next_cyclic_promise(contract);
vchan->processing = promise;
configure_pchan(pchan, promise);
vchan_cyclic_callback(&contract->vd);
} else {
vchan->processing = NULL;
vchan->pchan = NULL;
free_room = 1;
disableirqs |= BIT(bit);
release_pchan(priv, pchan);
}
spin_unlock(&vchan->vc.lock);
} else {
/* Half done interrupt */
if (contract->is_cyclic)
vchan_cyclic_callback(&contract->vd);
else
disableirqs |= BIT(bit);
}
}
/* Disable the IRQs for events we handled */
spin_lock(&priv->lock);
irqs = readl_relaxed(priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
writel_relaxed(irqs & ~disableirqs,
priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
spin_unlock(&priv->lock);
/* Writing 1 to the pending field will clear the pending interrupt */
writel_relaxed(pendirq, priv->base + SUN4I_DMA_IRQ_PENDING_STATUS_REG);
/*
* If a pchan was freed, we may be able to schedule something else,
* so have a look around
*/
if (free_room) {
for (i = 0; i < SUN4I_DMA_NR_MAX_VCHANS; i++) {
vchan = &priv->vchans[i];
spin_lock(&vchan->vc.lock);
__execute_vchan_pending(priv, vchan);
spin_unlock(&vchan->vc.lock);
}
}
/*
* Handle newer interrupts if some showed up, but only do it once
* to avoid a too long a loop
*/
if (allow_mitigation) {
pendirq = readl_relaxed(priv->base +
SUN4I_DMA_IRQ_PENDING_STATUS_REG);
if (pendirq) {
allow_mitigation = 0;
goto handle_pending;
}
}
return IRQ_HANDLED;
}
static int sun4i_dma_probe(struct platform_device *pdev)
{
struct sun4i_dma_dev *priv;
struct resource *res;
int i, j, ret;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(priv->base))
return PTR_ERR(priv->base);
priv->irq = platform_get_irq(pdev, 0);
if (priv->irq < 0) {
dev_err(&pdev->dev, "Cannot claim IRQ\n");
return priv->irq;
}
priv->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(priv->clk)) {
dev_err(&pdev->dev, "No clock specified\n");
return PTR_ERR(priv->clk);
}
platform_set_drvdata(pdev, priv);
spin_lock_init(&priv->lock);
dma_cap_zero(priv->slave.cap_mask);
dma_cap_set(DMA_PRIVATE, priv->slave.cap_mask);
dma_cap_set(DMA_MEMCPY, priv->slave.cap_mask);
dma_cap_set(DMA_CYCLIC, priv->slave.cap_mask);
dma_cap_set(DMA_SLAVE, priv->slave.cap_mask);
INIT_LIST_HEAD(&priv->slave.channels);
priv->slave.device_free_chan_resources = sun4i_dma_free_chan_resources;
priv->slave.device_tx_status = sun4i_dma_tx_status;
priv->slave.device_issue_pending = sun4i_dma_issue_pending;
priv->slave.device_prep_slave_sg = sun4i_dma_prep_slave_sg;
priv->slave.device_prep_dma_memcpy = sun4i_dma_prep_dma_memcpy;
priv->slave.device_prep_dma_cyclic = sun4i_dma_prep_dma_cyclic;
priv->slave.device_config = sun4i_dma_config;
priv->slave.device_terminate_all = sun4i_dma_terminate_all;
priv->slave.copy_align = 2;
priv->slave.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
priv->slave.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
priv->slave.directions = BIT(DMA_DEV_TO_MEM) |
BIT(DMA_MEM_TO_DEV);
priv->slave.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
priv->slave.dev = &pdev->dev;
priv->pchans = devm_kcalloc(&pdev->dev, SUN4I_DMA_NR_MAX_CHANNELS,
sizeof(struct sun4i_dma_pchan), GFP_KERNEL);
priv->vchans = devm_kcalloc(&pdev->dev, SUN4I_DMA_NR_MAX_VCHANS,
sizeof(struct sun4i_dma_vchan), GFP_KERNEL);
if (!priv->vchans || !priv->pchans)
return -ENOMEM;
/*
* [0..SUN4I_NDMA_NR_MAX_CHANNELS) are normal pchans, and
* [SUN4I_NDMA_NR_MAX_CHANNELS..SUN4I_DMA_NR_MAX_CHANNELS) are
* dedicated ones
*/
for (i = 0; i < SUN4I_NDMA_NR_MAX_CHANNELS; i++)
priv->pchans[i].base = priv->base +
SUN4I_NDMA_CHANNEL_REG_BASE(i);
for (j = 0; i < SUN4I_DMA_NR_MAX_CHANNELS; i++, j++) {
priv->pchans[i].base = priv->base +
SUN4I_DDMA_CHANNEL_REG_BASE(j);
priv->pchans[i].is_dedicated = 1;
}
for (i = 0; i < SUN4I_DMA_NR_MAX_VCHANS; i++) {
struct sun4i_dma_vchan *vchan = &priv->vchans[i];
spin_lock_init(&vchan->vc.lock);
vchan->vc.desc_free = sun4i_dma_free_contract;
vchan_init(&vchan->vc, &priv->slave);
}
ret = clk_prepare_enable(priv->clk);
if (ret) {
dev_err(&pdev->dev, "Couldn't enable the clock\n");
return ret;
}
/*
* Make sure the IRQs are all disabled and accounted for. The bootloader
* likes to leave these dirty
*/
writel(0, priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
writel(0xFFFFFFFF, priv->base + SUN4I_DMA_IRQ_PENDING_STATUS_REG);
ret = devm_request_irq(&pdev->dev, priv->irq, sun4i_dma_interrupt,
0, dev_name(&pdev->dev), priv);
if (ret) {
dev_err(&pdev->dev, "Cannot request IRQ\n");
goto err_clk_disable;
}
ret = dma_async_device_register(&priv->slave);
if (ret) {
dev_warn(&pdev->dev, "Failed to register DMA engine device\n");
goto err_clk_disable;
}
ret = of_dma_controller_register(pdev->dev.of_node, sun4i_dma_of_xlate,
priv);
if (ret) {
dev_err(&pdev->dev, "of_dma_controller_register failed\n");
goto err_dma_unregister;
}
dev_dbg(&pdev->dev, "Successfully probed SUN4I_DMA\n");
return 0;
err_dma_unregister:
dma_async_device_unregister(&priv->slave);
err_clk_disable:
clk_disable_unprepare(priv->clk);
return ret;
}
static int sun4i_dma_remove(struct platform_device *pdev)
{
struct sun4i_dma_dev *priv = platform_get_drvdata(pdev);
/* Disable IRQ so no more work is scheduled */
disable_irq(priv->irq);
of_dma_controller_free(pdev->dev.of_node);
dma_async_device_unregister(&priv->slave);
clk_disable_unprepare(priv->clk);
return 0;
}
static const struct of_device_id sun4i_dma_match[] = {
{ .compatible = "allwinner,sun4i-a10-dma" },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, sun4i_dma_match);
static struct platform_driver sun4i_dma_driver = {
.probe = sun4i_dma_probe,
.remove = sun4i_dma_remove,
.driver = {
.name = "sun4i-dma",
.of_match_table = sun4i_dma_match,
},
};
module_platform_driver(sun4i_dma_driver);
MODULE_DESCRIPTION("Allwinner A10 Dedicated DMA Controller Driver");
MODULE_AUTHOR("Emilio López <emilio@elopez.com.ar>");
MODULE_LICENSE("GPL");
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