// SPDX-License-Identifier: GPL-2.0+
/*
* BCM2835 DMA engine support
*
* Author: Florian Meier <[email protected]>
* Copyright 2013
*
* Based on
* OMAP DMAengine support by Russell King
*
* BCM2708 DMA Driver
* Copyright (C) 2010 Broadcom
*
* Raspberry Pi PCM I2S ALSA Driver
* Copyright (c) by Phil Poole 2013
*
* MARVELL MMP Peripheral DMA Driver
* Copyright 2012 Marvell International Ltd.
*/
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/of.h>
#include <linux/of_dma.h>
#include "virt-dma.h"
#define BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED 14
#define BCM2835_DMA_CHAN_NAME_SIZE 8
/**
* struct bcm2835_dmadev - BCM2835 DMA controller
* @ddev: DMA device
* @base: base address of register map
* @zero_page: bus address of zero page (to detect transactions copying from
* zero page and avoid accessing memory if so)
*/
struct bcm2835_dmadev {
struct dma_device ddev;
void __iomem *base;
dma_addr_t zero_page;
};
struct bcm2835_dma_cb {
uint32_t info;
uint32_t src;
uint32_t dst;
uint32_t length;
uint32_t stride;
uint32_t next;
uint32_t pad[2];
};
struct bcm2835_cb_entry {
struct bcm2835_dma_cb *cb;
dma_addr_t paddr;
};
struct bcm2835_chan {
struct virt_dma_chan vc;
struct dma_slave_config cfg;
unsigned int dreq;
int ch;
struct bcm2835_desc *desc;
struct dma_pool *cb_pool;
void __iomem *chan_base;
int irq_number;
unsigned int irq_flags;
bool is_lite_channel;
};
struct bcm2835_desc {
struct bcm2835_chan *c;
struct virt_dma_desc vd;
enum dma_transfer_direction dir;
unsigned int frames;
size_t size;
bool cyclic;
struct bcm2835_cb_entry cb_list[];
};
#define BCM2835_DMA_CS 0x00
#define BCM2835_DMA_ADDR 0x04
#define BCM2835_DMA_TI 0x08
#define BCM2835_DMA_SOURCE_AD 0x0c
#define BCM2835_DMA_DEST_AD 0x10
#define BCM2835_DMA_LEN 0x14
#define BCM2835_DMA_STRIDE 0x18
#define BCM2835_DMA_NEXTCB 0x1c
#define BCM2835_DMA_DEBUG 0x20
/* DMA CS Control and Status bits */
#define BCM2835_DMA_ACTIVE BIT(0) /* activate the DMA */
#define BCM2835_DMA_END BIT(1) /* current CB has ended */
#define BCM2835_DMA_INT BIT(2) /* interrupt status */
#define BCM2835_DMA_DREQ BIT(3) /* DREQ state */
#define BCM2835_DMA_ISPAUSED BIT(4) /* Pause requested or not active */
#define BCM2835_DMA_ISHELD BIT(5) /* Is held by DREQ flow control */
#define BCM2835_DMA_WAITING_FOR_WRITES BIT(6) /* waiting for last
* AXI-write to ack
*/
#define BCM2835_DMA_ERR BIT(8)
#define BCM2835_DMA_PRIORITY(x) ((x & 15) << 16) /* AXI priority */
#define BCM2835_DMA_PANIC_PRIORITY(x) ((x & 15) << 20) /* panic priority */
/* current value of TI.BCM2835_DMA_WAIT_RESP */
#define BCM2835_DMA_WAIT_FOR_WRITES BIT(28)
#define BCM2835_DMA_DIS_DEBUG BIT(29) /* disable debug pause signal */
#define BCM2835_DMA_ABORT BIT(30) /* Stop current CB, go to next, WO */
#define BCM2835_DMA_RESET BIT(31) /* WO, self clearing */
/* Transfer information bits - also bcm2835_cb.info field */
#define BCM2835_DMA_INT_EN BIT(0)
#define BCM2835_DMA_TDMODE BIT(1) /* 2D-Mode */
#define BCM2835_DMA_WAIT_RESP BIT(3) /* wait for AXI-write to be acked */
#define BCM2835_DMA_D_INC BIT(4)
#define BCM2835_DMA_D_WIDTH BIT(5) /* 128bit writes if set */
#define BCM2835_DMA_D_DREQ BIT(6) /* enable DREQ for destination */
#define BCM2835_DMA_D_IGNORE BIT(7) /* ignore destination writes */
#define BCM2835_DMA_S_INC BIT(8)
#define BCM2835_DMA_S_WIDTH BIT(9) /* 128bit writes if set */
#define BCM2835_DMA_S_DREQ BIT(10) /* enable SREQ for source */
#define BCM2835_DMA_S_IGNORE BIT(11) /* ignore source reads - read 0 */
#define BCM2835_DMA_BURST_LENGTH(x) ((x & 15) << 12)
#define BCM2835_DMA_PER_MAP(x) ((x & 31) << 16) /* REQ source */
#define BCM2835_DMA_WAIT(x) ((x & 31) << 21) /* add DMA-wait cycles */
#define BCM2835_DMA_NO_WIDE_BURSTS BIT(26) /* no 2 beat write bursts */
/* debug register bits */
#define BCM2835_DMA_DEBUG_LAST_NOT_SET_ERR BIT(0)
#define BCM2835_DMA_DEBUG_FIFO_ERR BIT(1)
#define BCM2835_DMA_DEBUG_READ_ERR BIT(2)
#define BCM2835_DMA_DEBUG_OUTSTANDING_WRITES_SHIFT 4
#define BCM2835_DMA_DEBUG_OUTSTANDING_WRITES_BITS 4
#define BCM2835_DMA_DEBUG_ID_SHIFT 16
#define BCM2835_DMA_DEBUG_ID_BITS 9
#define BCM2835_DMA_DEBUG_STATE_SHIFT 16
#define BCM2835_DMA_DEBUG_STATE_BITS 9
#define BCM2835_DMA_DEBUG_VERSION_SHIFT 25
#define BCM2835_DMA_DEBUG_VERSION_BITS 3
#define BCM2835_DMA_DEBUG_LITE BIT(28)
/* shared registers for all dma channels */
#define BCM2835_DMA_INT_STATUS 0xfe0
#define BCM2835_DMA_ENABLE 0xff0
#define BCM2835_DMA_DATA_TYPE_S8 1
#define BCM2835_DMA_DATA_TYPE_S16 2
#define BCM2835_DMA_DATA_TYPE_S32 4
#define BCM2835_DMA_DATA_TYPE_S128 16
/* Valid only for channels 0 - 14, 15 has its own base address */
#define BCM2835_DMA_CHAN(n) ((n) << 8) /* Base address */
#define BCM2835_DMA_CHANIO(base, n) ((base) + BCM2835_DMA_CHAN(n))
/* the max dma length for different channels */
#define MAX_DMA_LEN SZ_1G
#define MAX_LITE_DMA_LEN (SZ_64K - 4)
static inline size_t bcm2835_dma_max_frame_length(struct bcm2835_chan *c)
{
/* lite and normal channels have different max frame length */
return c->is_lite_channel ? MAX_LITE_DMA_LEN : MAX_DMA_LEN;
}
/* how many frames of max_len size do we need to transfer len bytes */
static inline size_t bcm2835_dma_frames_for_length(size_t len,
size_t max_len)
{
return DIV_ROUND_UP(len, max_len);
}
static inline struct bcm2835_dmadev *to_bcm2835_dma_dev(struct dma_device *d)
{
return container_of(d, struct bcm2835_dmadev, ddev);
}
static inline struct bcm2835_chan *to_bcm2835_dma_chan(struct dma_chan *c)
{
return container_of(c, struct bcm2835_chan, vc.chan);
}
static inline struct bcm2835_desc *to_bcm2835_dma_desc(
struct dma_async_tx_descriptor *t)
{
return container_of(t, struct bcm2835_desc, vd.tx);
}
static void bcm2835_dma_free_cb_chain(struct bcm2835_desc *desc)
{
size_t i;
for (i = 0; i < desc->frames; i++)
dma_pool_free(desc->c->cb_pool, desc->cb_list[i].cb,
desc->cb_list[i].paddr);
kfree(desc);
}
static void bcm2835_dma_desc_free(struct virt_dma_desc *vd)
{
bcm2835_dma_free_cb_chain(
container_of(vd, struct bcm2835_desc, vd));
}
static void bcm2835_dma_create_cb_set_length(
struct bcm2835_chan *chan,
struct bcm2835_dma_cb *control_block,
size_t len,
size_t period_len,
size_t *total_len,
u32 finalextrainfo)
{
size_t max_len = bcm2835_dma_max_frame_length(chan);
/* set the length taking lite-channel limitations into account */
control_block->length = min_t(u32, len, max_len);
/* finished if we have no period_length */
if (!period_len)
return;
/*
* period_len means: that we need to generate
* transfers that are terminating at every
* multiple of period_len - this is typically
* used to set the interrupt flag in info
* which is required during cyclic transfers
*/
/* have we filled in period_length yet? */
if (*total_len + control_block->length < period_len) {
/* update number of bytes in this period so far */
*total_len += control_block->length;
return;
}
/* calculate the length that remains to reach period_length */
control_block->length = period_len - *total_len;
/* reset total_length for next period */
*total_len = 0;
/* add extrainfo bits in info */
control_block->info |= finalextrainfo;
}
static inline size_t bcm2835_dma_count_frames_for_sg(
struct bcm2835_chan *c,
struct scatterlist *sgl,
unsigned int sg_len)
{
size_t frames = 0;
struct scatterlist *sgent;
unsigned int i;
size_t plength = bcm2835_dma_max_frame_length(c);
for_each_sg(sgl, sgent, sg_len, i)
frames += bcm2835_dma_frames_for_length(
sg_dma_len(sgent), plength);
return frames;
}
/**
* bcm2835_dma_create_cb_chain - create a control block and fills data in
*
* @chan: the @dma_chan for which we run this
* @direction: the direction in which we transfer
* @cyclic: it is a cyclic transfer
* @info: the default info bits to apply per controlblock
* @frames: number of controlblocks to allocate
* @src: the src address to assign (if the S_INC bit is set
* in @info, then it gets incremented)
* @dst: the dst address to assign (if the D_INC bit is set
* in @info, then it gets incremented)
* @buf_len: the full buffer length (may also be 0)
* @period_len: the period length when to apply @finalextrainfo
* in addition to the last transfer
* this will also break some control-blocks early
* @finalextrainfo: additional bits in last controlblock
* (or when period_len is reached in case of cyclic)
* @gfp: the GFP flag to use for allocation
*/
static struct bcm2835_desc *bcm2835_dma_create_cb_chain(
struct dma_chan *chan, enum dma_transfer_direction direction,
bool cyclic, u32 info, u32 finalextrainfo, size_t frames,
dma_addr_t src, dma_addr_t dst, size_t buf_len,
size_t period_len, gfp_t gfp)
{
struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
size_t len = buf_len, total_len;
size_t frame;
struct bcm2835_desc *d;
struct bcm2835_cb_entry *cb_entry;
struct bcm2835_dma_cb *control_block;
if (!frames)
return NULL;
/* allocate and setup the descriptor. */
d = kzalloc(struct_size(d, cb_list, frames), gfp);
if (!d)
return NULL;
d->c = c;
d->dir = direction;
d->cyclic = cyclic;
/*
* Iterate over all frames, create a control block
* for each frame and link them together.
*/
for (frame = 0, total_len = 0; frame < frames; d->frames++, frame++) {
cb_entry = &d->cb_list[frame];
cb_entry->cb = dma_pool_alloc(c->cb_pool, gfp,
&cb_entry->paddr);
if (!cb_entry->cb)
goto error_cb;
/* fill in the control block */
control_block = cb_entry->cb;
control_block->info = info;
control_block->src = src;
control_block->dst = dst;
control_block->stride = 0;
control_block->next = 0;
/* set up length in control_block if requested */
if (buf_len) {
/* calculate length honoring period_length */
bcm2835_dma_create_cb_set_length(
c, control_block,
len, period_len, &total_len,
cyclic ? finalextrainfo : 0);
/* calculate new remaining length */
len -= control_block->length;
}
/* link this the last controlblock */
if (frame)
d->cb_list[frame - 1].cb->next = cb_entry->paddr;
/* update src and dst and length */
if (src && (info & BCM2835_DMA_S_INC))
src += control_block->length;
if (dst && (info & BCM2835_DMA_D_INC))
dst += control_block->length;
/* Length of total transfer */
d->size += control_block->length;
}
/* the last frame requires extra flags */
d->cb_list[d->frames - 1].cb->info |= finalextrainfo;
/* detect a size mismatch */
if (buf_len && (d->size != buf_len))
goto error_cb;
return d;
error_cb:
bcm2835_dma_free_cb_chain(d);
return NULL;
}
static void bcm2835_dma_fill_cb_chain_with_sg(
struct dma_chan *chan,
enum dma_transfer_direction direction,
struct bcm2835_cb_entry *cb,
struct scatterlist *sgl,
unsigned int sg_len)
{
struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
size_t len, max_len;
unsigned int i;
dma_addr_t addr;
struct scatterlist *sgent;
max_len = bcm2835_dma_max_frame_length(c);
for_each_sg(sgl, sgent, sg_len, i) {
for (addr = sg_dma_address(sgent), len = sg_dma_len(sgent);
len > 0;
addr += cb->cb->length, len -= cb->cb->length, cb++) {
if (direction == DMA_DEV_TO_MEM)
cb->cb->dst = addr;
else
cb->cb->src = addr;
cb->cb->length = min(len, max_len);
}
}
}
static void bcm2835_dma_abort(struct bcm2835_chan *c)
{
void __iomem *chan_base = c->chan_base;
long int timeout = 10000;
/*
* A zero control block address means the channel is idle.
* (The ACTIVE flag in the CS register is not a reliable indicator.)
*/
if (!readl(chan_base + BCM2835_DMA_ADDR))
return;
/* Write 0 to the active bit - Pause the DMA */
writel(0, chan_base + BCM2835_DMA_CS);
/* Wait for any current AXI transfer to complete */
while ((readl(chan_base + BCM2835_DMA_CS) &
BCM2835_DMA_WAITING_FOR_WRITES) && --timeout)
cpu_relax();
/* Peripheral might be stuck and fail to signal AXI write responses */
if (!timeout)
dev_err(c->vc.chan.device->dev,
"failed to complete outstanding writes\n");
writel(BCM2835_DMA_RESET, chan_base + BCM2835_DMA_CS);
}
static void bcm2835_dma_start_desc(struct bcm2835_chan *c)
{
struct virt_dma_desc *vd = vchan_next_desc(&c->vc);
struct bcm2835_desc *d;
if (!vd) {
c->desc = NULL;
return;
}
list_del(&vd->node);
c->desc = d = to_bcm2835_dma_desc(&vd->tx);
writel(d->cb_list[0].paddr, c->chan_base + BCM2835_DMA_ADDR);
writel(BCM2835_DMA_ACTIVE, c->chan_base + BCM2835_DMA_CS);
}
static irqreturn_t bcm2835_dma_callback(int irq, void *data)
{
struct bcm2835_chan *c = data;
struct bcm2835_desc *d;
unsigned long flags;
/* check the shared interrupt */
if (c->irq_flags & IRQF_SHARED) {
/* check if the interrupt is enabled */
flags = readl(c->chan_base + BCM2835_DMA_CS);
/* if not set then we are not the reason for the irq */
if (!(flags & BCM2835_DMA_INT))
return IRQ_NONE;
}
spin_lock_irqsave(&c->vc.lock, flags);
/*
* Clear the INT flag to receive further interrupts. Keep the channel
* active in case the descriptor is cyclic or in case the client has
* already terminated the descriptor and issued a new one. (May happen
* if this IRQ handler is threaded.) If the channel is finished, it
* will remain idle despite the ACTIVE flag being set.
*/
writel(BCM2835_DMA_INT | BCM2835_DMA_ACTIVE,
c->chan_base + BCM2835_DMA_CS);
d = c->desc;
if (d) {
if (d->cyclic) {
/* call the cyclic callback */
vchan_cyclic_callback(&d->vd);
} else if (!readl(c->chan_base + BCM2835_DMA_ADDR)) {
vchan_cookie_complete(&c->desc->vd);
bcm2835_dma_start_desc(c);
}
}
spin_unlock_irqrestore(&c->vc.lock, flags);
return IRQ_HANDLED;
}
static int bcm2835_dma_alloc_chan_resources(struct dma_chan *chan)
{
struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
struct device *dev = c->vc.chan.device->dev;
dev_dbg(dev, "Allocating DMA channel %d\n", c->ch);
/*
* Control blocks are 256 bit in length and must start at a 256 bit
* (32 byte) aligned address (BCM2835 ARM Peripherals, sec. 4.2.1.1).
*/
c->cb_pool = dma_pool_create(dev_name(dev), dev,
sizeof(struct bcm2835_dma_cb), 32, 0);
if (!c->cb_pool) {
dev_err(dev, "unable to allocate descriptor pool\n");
return -ENOMEM;
}
return request_irq(c->irq_number, bcm2835_dma_callback,
c->irq_flags, "DMA IRQ", c);
}
static void bcm2835_dma_free_chan_resources(struct dma_chan *chan)
{
struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
vchan_free_chan_resources(&c->vc);
free_irq(c->irq_number, c);
dma_pool_destroy(c->cb_pool);
dev_dbg(c->vc.chan.device->dev, "Freeing DMA channel %u\n", c->ch);
}
static size_t bcm2835_dma_desc_size(struct bcm2835_desc *d)
{
return d->size;
}
static size_t bcm2835_dma_desc_size_pos(struct bcm2835_desc *d, dma_addr_t addr)
{
unsigned int i;
size_t size;
for (size = i = 0; i < d->frames; i++) {
struct bcm2835_dma_cb *control_block = d->cb_list[i].cb;
size_t this_size = control_block->length;
dma_addr_t dma;
if (d->dir == DMA_DEV_TO_MEM)
dma = control_block->dst;
else
dma = control_block->src;
if (size)
size += this_size;
else if (addr >= dma && addr < dma + this_size)
size += dma + this_size - addr;
}
return size;
}
static enum dma_status bcm2835_dma_tx_status(struct dma_chan *chan,
dma_cookie_t cookie, struct dma_tx_state *txstate)
{
struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
struct virt_dma_desc *vd;
enum dma_status ret;
unsigned long flags;
ret = dma_cookie_status(chan, cookie, txstate);
if (ret == DMA_COMPLETE || !txstate)
return ret;
spin_lock_irqsave(&c->vc.lock, flags);
vd = vchan_find_desc(&c->vc, cookie);
if (vd) {
txstate->residue =
bcm2835_dma_desc_size(to_bcm2835_dma_desc(&vd->tx));
} else if (c->desc && c->desc->vd.tx.cookie == cookie) {
struct bcm2835_desc *d = c->desc;
dma_addr_t pos;
if (d->dir == DMA_MEM_TO_DEV)
pos = readl(c->chan_base + BCM2835_DMA_SOURCE_AD);
else if (d->dir == DMA_DEV_TO_MEM)
pos = readl(c->chan_base + BCM2835_DMA_DEST_AD);
else
pos = 0;
txstate->residue = bcm2835_dma_desc_size_pos(d, pos);
} else {
txstate->residue = 0;
}
spin_unlock_irqrestore(&c->vc.lock, flags);
return ret;
}
static void bcm2835_dma_issue_pending(struct dma_chan *chan)
{
struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
unsigned long flags;
spin_lock_irqsave(&c->vc.lock, flags);
if (vchan_issue_pending(&c->vc) && !c->desc)
bcm2835_dma_start_desc(c);
spin_unlock_irqrestore(&c->vc.lock, flags);
}
static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_memcpy(
struct dma_chan *chan, dma_addr_t dst, dma_addr_t src,
size_t len, unsigned long flags)
{
struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
struct bcm2835_desc *d;
u32 info = BCM2835_DMA_D_INC | BCM2835_DMA_S_INC;
u32 extra = BCM2835_DMA_INT_EN | BCM2835_DMA_WAIT_RESP;
size_t max_len = bcm2835_dma_max_frame_length(c);
size_t frames;
/* if src, dst or len is not given return with an error */
if (!src || !dst || !len)
return NULL;
/* calculate number of frames */
frames = bcm2835_dma_frames_for_length(len, max_len);
/* allocate the CB chain - this also fills in the pointers */
d = bcm2835_dma_create_cb_chain(chan, DMA_MEM_TO_MEM, false,
info, extra, frames,
src, dst, len, 0, GFP_KERNEL);
if (!d)
return NULL;
return vchan_tx_prep(&c->vc, &d->vd, flags);
}
static struct dma_async_tx_descriptor *bcm2835_dma_prep_slave_sg(
struct dma_chan *chan,
struct scatterlist *sgl, unsigned int sg_len,
enum dma_transfer_direction direction,
unsigned long flags, void *context)
{
struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
struct bcm2835_desc *d;
dma_addr_t src = 0, dst = 0;
u32 info = BCM2835_DMA_WAIT_RESP;
u32 extra = BCM2835_DMA_INT_EN;
size_t frames;
if (!is_slave_direction(direction)) {
dev_err(chan->device->dev,
"%s: bad direction?\n", __func__);
return NULL;
}
if (c->dreq != 0)
info |= BCM2835_DMA_PER_MAP(c->dreq);
if (direction == DMA_DEV_TO_MEM) {
if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
return NULL;
src = c->cfg.src_addr;
info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC;
} else {
if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
return NULL;
dst = c->cfg.dst_addr;
info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC;
}
/* count frames in sg list */
frames = bcm2835_dma_count_frames_for_sg(c, sgl, sg_len);
/* allocate the CB chain */
d = bcm2835_dma_create_cb_chain(chan, direction, false,
info, extra,
frames, src, dst, 0, 0,
GFP_NOWAIT);
if (!d)
return NULL;
/* fill in frames with scatterlist pointers */
bcm2835_dma_fill_cb_chain_with_sg(chan, direction, d->cb_list,
sgl, sg_len);
return vchan_tx_prep(&c->vc, &d->vd, flags);
}
static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic(
struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
size_t period_len, enum dma_transfer_direction direction,
unsigned long flags)
{
struct bcm2835_dmadev *od = to_bcm2835_dma_dev(chan->device);
struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
struct bcm2835_desc *d;
dma_addr_t src, dst;
u32 info = BCM2835_DMA_WAIT_RESP;
u32 extra = 0;
size_t max_len = bcm2835_dma_max_frame_length(c);
size_t frames;
/* Grab configuration */
if (!is_slave_direction(direction)) {
dev_err(chan->device->dev, "%s: bad direction?\n", __func__);
return NULL;
}
if (!buf_len) {
dev_err(chan->device->dev,
"%s: bad buffer length (= 0)\n", __func__);
return NULL;
}
if (flags & DMA_PREP_INTERRUPT)
extra |= BCM2835_DMA_INT_EN;
else
period_len = buf_len;
/*
* warn if buf_len is not a multiple of period_len - this may leed
* to unexpected latencies for interrupts and thus audiable clicks
*/
if (buf_len % period_len)
dev_warn_once(chan->device->dev,
"%s: buffer_length (%zd) is not a multiple of period_len (%zd)\n",
__func__, buf_len, period_len);
/* Setup DREQ channel */
if (c->dreq != 0)
info |= BCM2835_DMA_PER_MAP(c->dreq);
if (direction == DMA_DEV_TO_MEM) {
if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
return NULL;
src = c->cfg.src_addr;
dst = buf_addr;
info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC;
} else {
if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
return NULL;
dst = c->cfg.dst_addr;
src = buf_addr;
info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC;
/* non-lite channels can write zeroes w/o accessing memory */
if (buf_addr == od->zero_page && !c->is_lite_channel)
info |= BCM2835_DMA_S_IGNORE;
}
/* calculate number of frames */
frames = /* number of periods */
DIV_ROUND_UP(buf_len, period_len) *
/* number of frames per period */
bcm2835_dma_frames_for_length(period_len, max_len);
/*
* allocate the CB chain
* note that we need to use GFP_NOWAIT, as the ALSA i2s dmaengine
* implementation calls prep_dma_cyclic with interrupts disabled.
*/
d = bcm2835_dma_create_cb_chain(chan, direction, true,
info, extra,
frames, src, dst, buf_len,
period_len, GFP_NOWAIT);
if (!d)
return NULL;
/* wrap around into a loop */
d->cb_list[d->frames - 1].cb->next = d->cb_list[0].paddr;
return vchan_tx_prep(&c->vc, &d->vd, flags);
}
static int bcm2835_dma_slave_config(struct dma_chan *chan,
struct dma_slave_config *cfg)
{
struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
c->cfg = *cfg;
return 0;
}
static int bcm2835_dma_terminate_all(struct dma_chan *chan)
{
struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
unsigned long flags;
LIST_HEAD(head);
spin_lock_irqsave(&c->vc.lock, flags);
/* stop DMA activity */
if (c->desc) {
vchan_terminate_vdesc(&c->desc->vd);
c->desc = NULL;
bcm2835_dma_abort(c);
}
vchan_get_all_descriptors(&c->vc, &head);
spin_unlock_irqrestore(&c->vc.lock, flags);
vchan_dma_desc_free_list(&c->vc, &head);
return 0;
}
static void bcm2835_dma_synchronize(struct dma_chan *chan)
{
struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
vchan_synchronize(&c->vc);
}
static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id,
int irq, unsigned int irq_flags)
{
struct bcm2835_chan *c;
c = devm_kzalloc(d->ddev.dev, sizeof(*c), GFP_KERNEL);
if (!c)
return -ENOMEM;
c->vc.desc_free = bcm2835_dma_desc_free;
vchan_init(&c->vc, &d->ddev);
c->chan_base = BCM2835_DMA_CHANIO(d->base, chan_id);
c->ch = chan_id;
c->irq_number = irq;
c->irq_flags = irq_flags;
/* check in DEBUG register if this is a LITE channel */
if (readl(c->chan_base + BCM2835_DMA_DEBUG) &
BCM2835_DMA_DEBUG_LITE)
c->is_lite_channel = true;
return 0;
}
static void bcm2835_dma_free(struct bcm2835_dmadev *od)
{
struct bcm2835_chan *c, *next;
list_for_each_entry_safe(c, next, &od->ddev.channels,
vc.chan.device_node) {
list_del(&c->vc.chan.device_node);
tasklet_kill(&c->vc.task);
}
dma_unmap_page_attrs(od->ddev.dev, od->zero_page, PAGE_SIZE,
DMA_TO_DEVICE, DMA_ATTR_SKIP_CPU_SYNC);
}
static const struct of_device_id bcm2835_dma_of_match[] = {
{ .compatible = "brcm,bcm2835-dma", },
{},
};
MODULE_DEVICE_TABLE(of, bcm2835_dma_of_match);
static struct dma_chan *bcm2835_dma_xlate(struct of_phandle_args *spec,
struct of_dma *ofdma)
{
struct bcm2835_dmadev *d = ofdma->of_dma_data;
struct dma_chan *chan;
chan = dma_get_any_slave_channel(&d->ddev);
if (!chan)
return NULL;
/* Set DREQ from param */
to_bcm2835_dma_chan(chan)->dreq = spec->args[0];
return chan;
}
static int bcm2835_dma_probe(struct platform_device *pdev)
{
struct bcm2835_dmadev *od;
void __iomem *base;
int rc;
int i, j;
int irq[BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED + 1];
int irq_flags;
uint32_t chans_available;
char chan_name[BCM2835_DMA_CHAN_NAME_SIZE];
if (!pdev->dev.dma_mask)
pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
if (rc) {
dev_err(&pdev->dev, "Unable to set DMA mask\n");
return rc;
}
od = devm_kzalloc(&pdev->dev, sizeof(*od), GFP_KERNEL);
if (!od)
return -ENOMEM;
dma_set_max_seg_size(&pdev->dev, 0x3FFFFFFF);
base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(base))
return PTR_ERR(base);
od->base = base;
dma_cap_set(DMA_SLAVE, od->ddev.cap_mask);
dma_cap_set(DMA_PRIVATE, od->ddev.cap_mask);
dma_cap_set(DMA_CYCLIC, od->ddev.cap_mask);
dma_cap_set(DMA_MEMCPY, od->ddev.cap_mask);
od->ddev.device_alloc_chan_resources = bcm2835_dma_alloc_chan_resources;
od->ddev.device_free_chan_resources = bcm2835_dma_free_chan_resources;
od->ddev.device_tx_status = bcm2835_dma_tx_status;
od->ddev.device_issue_pending = bcm2835_dma_issue_pending;
od->ddev.device_prep_dma_cyclic = bcm2835_dma_prep_dma_cyclic;
od->ddev.device_prep_slave_sg = bcm2835_dma_prep_slave_sg;
od->ddev.device_prep_dma_memcpy = bcm2835_dma_prep_dma_memcpy;
od->ddev.device_config = bcm2835_dma_slave_config;
od->ddev.device_terminate_all = bcm2835_dma_terminate_all;
od->ddev.device_synchronize = bcm2835_dma_synchronize;
od->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
od->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
od->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) |
BIT(DMA_MEM_TO_MEM);
od->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
od->ddev.descriptor_reuse = true;
od->ddev.dev = &pdev->dev;
INIT_LIST_HEAD(&od->ddev.channels);
platform_set_drvdata(pdev, od);
od->zero_page = dma_map_page_attrs(od->ddev.dev, ZERO_PAGE(0), 0,
PAGE_SIZE, DMA_TO_DEVICE,
DMA_ATTR_SKIP_CPU_SYNC);
if (dma_mapping_error(od->ddev.dev, od->zero_page)) {
dev_err(&pdev->dev, "Failed to map zero page\n");
return -ENOMEM;
}
/* Request DMA channel mask from device tree */
if (of_property_read_u32(pdev->dev.of_node,
"brcm,dma-channel-mask",
&chans_available)) {
dev_err(&pdev->dev, "Failed to get channel mask\n");
rc = -EINVAL;
goto err_no_dma;
}
/* get irqs for each channel that we support */
for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) {
/* skip masked out channels */
if (!(chans_available & (1 << i))) {
irq[i] = -1;
continue;
}
/* get the named irq */
snprintf(chan_name, sizeof(chan_name), "dma%i", i);
irq[i] = platform_get_irq_byname(pdev, chan_name);
if (irq[i] >= 0)
continue;
/* legacy device tree case handling */
dev_warn_once(&pdev->dev,
"missing interrupt-names property in device tree - legacy interpretation is used\n");
/*
* in case of channel >= 11
* use the 11th interrupt and that is shared
*/
irq[i] = platform_get_irq(pdev, i < 11 ? i : 11);
}
/* get irqs for each channel */
for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) {
/* skip channels without irq */
if (irq[i] < 0)
continue;
/* check if there are other channels that also use this irq */
irq_flags = 0;
for (j = 0; j <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; j++)
if ((i != j) && (irq[j] == irq[i])) {
irq_flags = IRQF_SHARED;
break;
}
/* initialize the channel */
rc = bcm2835_dma_chan_init(od, i, irq[i], irq_flags);
if (rc)
goto err_no_dma;
}
dev_dbg(&pdev->dev, "Initialized %i DMA channels\n", i);
/* Device-tree DMA controller registration */
rc = of_dma_controller_register(pdev->dev.of_node,
bcm2835_dma_xlate, od);
if (rc) {
dev_err(&pdev->dev, "Failed to register DMA controller\n");
goto err_no_dma;
}
rc = dma_async_device_register(&od->ddev);
if (rc) {
dev_err(&pdev->dev,
"Failed to register slave DMA engine device: %d\n", rc);
goto err_no_dma;
}
dev_dbg(&pdev->dev, "Load BCM2835 DMA engine driver\n");
return 0;
err_no_dma:
bcm2835_dma_free(od);
return rc;
}
static void bcm2835_dma_remove(struct platform_device *pdev)
{
struct bcm2835_dmadev *od = platform_get_drvdata(pdev);
dma_async_device_unregister(&od->ddev);
bcm2835_dma_free(od);
}
static struct platform_driver bcm2835_dma_driver = {
.probe = bcm2835_dma_probe,
.remove_new = bcm2835_dma_remove,
.driver = {
.name = "bcm2835-dma",
.of_match_table = of_match_ptr(bcm2835_dma_of_match),
},
};
module_platform_driver(bcm2835_dma_driver);
MODULE_ALIAS("platform:bcm2835-dma");
MODULE_DESCRIPTION("BCM2835 DMA engine driver");
MODULE_AUTHOR("Florian Meier <[email protected]>");
MODULE_LICENSE("GPL");
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