spi/ep93xx: add DMA support
This patch adds DMA support for the EP93xx SPI driver. By default the DMA is not enabled but it can be enabled by setting ep93xx_spi_info.use_dma to true in board configuration file. Note that the SPI driver still uses PIO for small transfers (<= 8 bytes) for performance reasons. Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi> Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com> Acked-by: Vinod Koul <vinod.koul@intel.com> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Mika Westerberg
Grant Likely
parent
71cebd7002
commit
626a96db11
4 changed files with 308 additions and 13 deletions
|
|
@ -88,6 +88,16 @@ static void __init ts72xx_init_machine(void)
|
|||
ARRAY_SIZE(ts72xx_spi_devices));
|
||||
}
|
||||
|
||||
The driver can use DMA for the transfers also. In this case ts72xx_spi_info
|
||||
becomes:
|
||||
|
||||
static struct ep93xx_spi_info ts72xx_spi_info = {
|
||||
.num_chipselect = ARRAY_SIZE(ts72xx_spi_devices),
|
||||
.use_dma = true;
|
||||
};
|
||||
|
||||
Note that CONFIG_EP93XX_DMA should be enabled as well.
|
||||
|
||||
Thanks to
|
||||
=========
|
||||
Martin Guy, H. Hartley Sweeten and others who helped me during development of
|
||||
|
|
|
|||
|
|
@ -488,11 +488,15 @@ static struct resource ep93xx_spi_resources[] = {
|
|||
},
|
||||
};
|
||||
|
||||
static u64 ep93xx_spi_dma_mask = DMA_BIT_MASK(32);
|
||||
|
||||
static struct platform_device ep93xx_spi_device = {
|
||||
.name = "ep93xx-spi",
|
||||
.id = 0,
|
||||
.dev = {
|
||||
.platform_data = &ep93xx_spi_master_data,
|
||||
.platform_data = &ep93xx_spi_master_data,
|
||||
.coherent_dma_mask = DMA_BIT_MASK(32),
|
||||
.dma_mask = &ep93xx_spi_dma_mask,
|
||||
},
|
||||
.num_resources = ARRAY_SIZE(ep93xx_spi_resources),
|
||||
.resource = ep93xx_spi_resources,
|
||||
|
|
|
|||
|
|
@ -7,9 +7,11 @@ struct spi_device;
|
|||
* struct ep93xx_spi_info - EP93xx specific SPI descriptor
|
||||
* @num_chipselect: number of chip selects on this board, must be
|
||||
* at least one
|
||||
* @use_dma: use DMA for the transfers
|
||||
*/
|
||||
struct ep93xx_spi_info {
|
||||
int num_chipselect;
|
||||
bool use_dma;
|
||||
};
|
||||
|
||||
/**
|
||||
|
|
|
|||
|
|
@ -1,7 +1,7 @@
|
|||
/*
|
||||
* Driver for Cirrus Logic EP93xx SPI controller.
|
||||
*
|
||||
* Copyright (c) 2010 Mika Westerberg
|
||||
* Copyright (C) 2010-2011 Mika Westerberg
|
||||
*
|
||||
* Explicit FIFO handling code was inspired by amba-pl022 driver.
|
||||
*
|
||||
|
|
@ -21,13 +21,16 @@
|
|||
#include <linux/err.h>
|
||||
#include <linux/delay.h>
|
||||
#include <linux/device.h>
|
||||
#include <linux/dmaengine.h>
|
||||
#include <linux/bitops.h>
|
||||
#include <linux/interrupt.h>
|
||||
#include <linux/platform_device.h>
|
||||
#include <linux/workqueue.h>
|
||||
#include <linux/sched.h>
|
||||
#include <linux/scatterlist.h>
|
||||
#include <linux/spi/spi.h>
|
||||
|
||||
#include <mach/dma.h>
|
||||
#include <mach/ep93xx_spi.h>
|
||||
|
||||
#define SSPCR0 0x0000
|
||||
|
|
@ -71,6 +74,7 @@
|
|||
* @pdev: pointer to platform device
|
||||
* @clk: clock for the controller
|
||||
* @regs_base: pointer to ioremap()'d registers
|
||||
* @sspdr_phys: physical address of the SSPDR register
|
||||
* @irq: IRQ number used by the driver
|
||||
* @min_rate: minimum clock rate (in Hz) supported by the controller
|
||||
* @max_rate: maximum clock rate (in Hz) supported by the controller
|
||||
|
|
@ -84,6 +88,14 @@
|
|||
* @rx: current byte in transfer to receive
|
||||
* @fifo_level: how full is FIFO (%0..%SPI_FIFO_SIZE - %1). Receiving one
|
||||
* frame decreases this level and sending one frame increases it.
|
||||
* @dma_rx: RX DMA channel
|
||||
* @dma_tx: TX DMA channel
|
||||
* @dma_rx_data: RX parameters passed to the DMA engine
|
||||
* @dma_tx_data: TX parameters passed to the DMA engine
|
||||
* @rx_sgt: sg table for RX transfers
|
||||
* @tx_sgt: sg table for TX transfers
|
||||
* @zeropage: dummy page used as RX buffer when only TX buffer is passed in by
|
||||
* the client
|
||||
*
|
||||
* This structure holds EP93xx SPI controller specific information. When
|
||||
* @running is %true, driver accepts transfer requests from protocol drivers.
|
||||
|
|
@ -100,6 +112,7 @@ struct ep93xx_spi {
|
|||
const struct platform_device *pdev;
|
||||
struct clk *clk;
|
||||
void __iomem *regs_base;
|
||||
unsigned long sspdr_phys;
|
||||
int irq;
|
||||
unsigned long min_rate;
|
||||
unsigned long max_rate;
|
||||
|
|
@ -112,6 +125,13 @@ struct ep93xx_spi {
|
|||
size_t tx;
|
||||
size_t rx;
|
||||
size_t fifo_level;
|
||||
struct dma_chan *dma_rx;
|
||||
struct dma_chan *dma_tx;
|
||||
struct ep93xx_dma_data dma_rx_data;
|
||||
struct ep93xx_dma_data dma_tx_data;
|
||||
struct sg_table rx_sgt;
|
||||
struct sg_table tx_sgt;
|
||||
void *zeropage;
|
||||
};
|
||||
|
||||
/**
|
||||
|
|
@ -496,14 +516,195 @@ static int ep93xx_spi_read_write(struct ep93xx_spi *espi)
|
|||
espi->fifo_level++;
|
||||
}
|
||||
|
||||
if (espi->rx == t->len) {
|
||||
msg->actual_length += t->len;
|
||||
if (espi->rx == t->len)
|
||||
return 0;
|
||||
}
|
||||
|
||||
return -EINPROGRESS;
|
||||
}
|
||||
|
||||
static void ep93xx_spi_pio_transfer(struct ep93xx_spi *espi)
|
||||
{
|
||||
/*
|
||||
* Now everything is set up for the current transfer. We prime the TX
|
||||
* FIFO, enable interrupts, and wait for the transfer to complete.
|
||||
*/
|
||||
if (ep93xx_spi_read_write(espi)) {
|
||||
ep93xx_spi_enable_interrupts(espi);
|
||||
wait_for_completion(&espi->wait);
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* ep93xx_spi_dma_prepare() - prepares a DMA transfer
|
||||
* @espi: ep93xx SPI controller struct
|
||||
* @dir: DMA transfer direction
|
||||
*
|
||||
* Function configures the DMA, maps the buffer and prepares the DMA
|
||||
* descriptor. Returns a valid DMA descriptor in case of success and ERR_PTR
|
||||
* in case of failure.
|
||||
*/
|
||||
static struct dma_async_tx_descriptor *
|
||||
ep93xx_spi_dma_prepare(struct ep93xx_spi *espi, enum dma_data_direction dir)
|
||||
{
|
||||
struct spi_transfer *t = espi->current_msg->state;
|
||||
struct dma_async_tx_descriptor *txd;
|
||||
enum dma_slave_buswidth buswidth;
|
||||
struct dma_slave_config conf;
|
||||
struct scatterlist *sg;
|
||||
struct sg_table *sgt;
|
||||
struct dma_chan *chan;
|
||||
const void *buf, *pbuf;
|
||||
size_t len = t->len;
|
||||
int i, ret, nents;
|
||||
|
||||
if (bits_per_word(espi) > 8)
|
||||
buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
|
||||
else
|
||||
buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
|
||||
|
||||
memset(&conf, 0, sizeof(conf));
|
||||
conf.direction = dir;
|
||||
|
||||
if (dir == DMA_FROM_DEVICE) {
|
||||
chan = espi->dma_rx;
|
||||
buf = t->rx_buf;
|
||||
sgt = &espi->rx_sgt;
|
||||
|
||||
conf.src_addr = espi->sspdr_phys;
|
||||
conf.src_addr_width = buswidth;
|
||||
} else {
|
||||
chan = espi->dma_tx;
|
||||
buf = t->tx_buf;
|
||||
sgt = &espi->tx_sgt;
|
||||
|
||||
conf.dst_addr = espi->sspdr_phys;
|
||||
conf.dst_addr_width = buswidth;
|
||||
}
|
||||
|
||||
ret = dmaengine_slave_config(chan, &conf);
|
||||
if (ret)
|
||||
return ERR_PTR(ret);
|
||||
|
||||
/*
|
||||
* We need to split the transfer into PAGE_SIZE'd chunks. This is
|
||||
* because we are using @espi->zeropage to provide a zero RX buffer
|
||||
* for the TX transfers and we have only allocated one page for that.
|
||||
*
|
||||
* For performance reasons we allocate a new sg_table only when
|
||||
* needed. Otherwise we will re-use the current one. Eventually the
|
||||
* last sg_table is released in ep93xx_spi_release_dma().
|
||||
*/
|
||||
|
||||
nents = DIV_ROUND_UP(len, PAGE_SIZE);
|
||||
if (nents != sgt->nents) {
|
||||
sg_free_table(sgt);
|
||||
|
||||
ret = sg_alloc_table(sgt, nents, GFP_KERNEL);
|
||||
if (ret)
|
||||
return ERR_PTR(ret);
|
||||
}
|
||||
|
||||
pbuf = buf;
|
||||
for_each_sg(sgt->sgl, sg, sgt->nents, i) {
|
||||
size_t bytes = min_t(size_t, len, PAGE_SIZE);
|
||||
|
||||
if (buf) {
|
||||
sg_set_page(sg, virt_to_page(pbuf), bytes,
|
||||
offset_in_page(pbuf));
|
||||
} else {
|
||||
sg_set_page(sg, virt_to_page(espi->zeropage),
|
||||
bytes, 0);
|
||||
}
|
||||
|
||||
pbuf += bytes;
|
||||
len -= bytes;
|
||||
}
|
||||
|
||||
if (WARN_ON(len)) {
|
||||
dev_warn(&espi->pdev->dev, "len = %d expected 0!", len);
|
||||
return ERR_PTR(-EINVAL);
|
||||
}
|
||||
|
||||
nents = dma_map_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
|
||||
if (!nents)
|
||||
return ERR_PTR(-ENOMEM);
|
||||
|
||||
txd = chan->device->device_prep_slave_sg(chan, sgt->sgl, nents,
|
||||
dir, DMA_CTRL_ACK);
|
||||
if (!txd) {
|
||||
dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
|
||||
return ERR_PTR(-ENOMEM);
|
||||
}
|
||||
return txd;
|
||||
}
|
||||
|
||||
/**
|
||||
* ep93xx_spi_dma_finish() - finishes with a DMA transfer
|
||||
* @espi: ep93xx SPI controller struct
|
||||
* @dir: DMA transfer direction
|
||||
*
|
||||
* Function finishes with the DMA transfer. After this, the DMA buffer is
|
||||
* unmapped.
|
||||
*/
|
||||
static void ep93xx_spi_dma_finish(struct ep93xx_spi *espi,
|
||||
enum dma_data_direction dir)
|
||||
{
|
||||
struct dma_chan *chan;
|
||||
struct sg_table *sgt;
|
||||
|
||||
if (dir == DMA_FROM_DEVICE) {
|
||||
chan = espi->dma_rx;
|
||||
sgt = &espi->rx_sgt;
|
||||
} else {
|
||||
chan = espi->dma_tx;
|
||||
sgt = &espi->tx_sgt;
|
||||
}
|
||||
|
||||
dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
|
||||
}
|
||||
|
||||
static void ep93xx_spi_dma_callback(void *callback_param)
|
||||
{
|
||||
complete(callback_param);
|
||||
}
|
||||
|
||||
static void ep93xx_spi_dma_transfer(struct ep93xx_spi *espi)
|
||||
{
|
||||
struct spi_message *msg = espi->current_msg;
|
||||
struct dma_async_tx_descriptor *rxd, *txd;
|
||||
|
||||
rxd = ep93xx_spi_dma_prepare(espi, DMA_FROM_DEVICE);
|
||||
if (IS_ERR(rxd)) {
|
||||
dev_err(&espi->pdev->dev, "DMA RX failed: %ld\n", PTR_ERR(rxd));
|
||||
msg->status = PTR_ERR(rxd);
|
||||
return;
|
||||
}
|
||||
|
||||
txd = ep93xx_spi_dma_prepare(espi, DMA_TO_DEVICE);
|
||||
if (IS_ERR(txd)) {
|
||||
ep93xx_spi_dma_finish(espi, DMA_FROM_DEVICE);
|
||||
dev_err(&espi->pdev->dev, "DMA TX failed: %ld\n", PTR_ERR(rxd));
|
||||
msg->status = PTR_ERR(txd);
|
||||
return;
|
||||
}
|
||||
|
||||
/* We are ready when RX is done */
|
||||
rxd->callback = ep93xx_spi_dma_callback;
|
||||
rxd->callback_param = &espi->wait;
|
||||
|
||||
/* Now submit both descriptors and wait while they finish */
|
||||
dmaengine_submit(rxd);
|
||||
dmaengine_submit(txd);
|
||||
|
||||
dma_async_issue_pending(espi->dma_rx);
|
||||
dma_async_issue_pending(espi->dma_tx);
|
||||
|
||||
wait_for_completion(&espi->wait);
|
||||
|
||||
ep93xx_spi_dma_finish(espi, DMA_TO_DEVICE);
|
||||
ep93xx_spi_dma_finish(espi, DMA_FROM_DEVICE);
|
||||
}
|
||||
|
||||
/**
|
||||
* ep93xx_spi_process_transfer() - processes one SPI transfer
|
||||
* @espi: ep93xx SPI controller struct
|
||||
|
|
@ -556,13 +757,14 @@ static void ep93xx_spi_process_transfer(struct ep93xx_spi *espi,
|
|||
espi->tx = 0;
|
||||
|
||||
/*
|
||||
* Now everything is set up for the current transfer. We prime the TX
|
||||
* FIFO, enable interrupts, and wait for the transfer to complete.
|
||||
* There is no point of setting up DMA for the transfers which will
|
||||
* fit into the FIFO and can be transferred with a single interrupt.
|
||||
* So in these cases we will be using PIO and don't bother for DMA.
|
||||
*/
|
||||
if (ep93xx_spi_read_write(espi)) {
|
||||
ep93xx_spi_enable_interrupts(espi);
|
||||
wait_for_completion(&espi->wait);
|
||||
}
|
||||
if (espi->dma_rx && t->len > SPI_FIFO_SIZE)
|
||||
ep93xx_spi_dma_transfer(espi);
|
||||
else
|
||||
ep93xx_spi_pio_transfer(espi);
|
||||
|
||||
/*
|
||||
* In case of error during transmit, we bail out from processing
|
||||
|
|
@ -571,6 +773,8 @@ static void ep93xx_spi_process_transfer(struct ep93xx_spi *espi,
|
|||
if (msg->status)
|
||||
return;
|
||||
|
||||
msg->actual_length += t->len;
|
||||
|
||||
/*
|
||||
* After this transfer is finished, perform any possible
|
||||
* post-transfer actions requested by the protocol driver.
|
||||
|
|
@ -752,6 +956,75 @@ static irqreturn_t ep93xx_spi_interrupt(int irq, void *dev_id)
|
|||
return IRQ_HANDLED;
|
||||
}
|
||||
|
||||
static bool ep93xx_spi_dma_filter(struct dma_chan *chan, void *filter_param)
|
||||
{
|
||||
if (ep93xx_dma_chan_is_m2p(chan))
|
||||
return false;
|
||||
|
||||
chan->private = filter_param;
|
||||
return true;
|
||||
}
|
||||
|
||||
static int ep93xx_spi_setup_dma(struct ep93xx_spi *espi)
|
||||
{
|
||||
dma_cap_mask_t mask;
|
||||
int ret;
|
||||
|
||||
espi->zeropage = (void *)get_zeroed_page(GFP_KERNEL);
|
||||
if (!espi->zeropage)
|
||||
return -ENOMEM;
|
||||
|
||||
dma_cap_zero(mask);
|
||||
dma_cap_set(DMA_SLAVE, mask);
|
||||
|
||||
espi->dma_rx_data.port = EP93XX_DMA_SSP;
|
||||
espi->dma_rx_data.direction = DMA_FROM_DEVICE;
|
||||
espi->dma_rx_data.name = "ep93xx-spi-rx";
|
||||
|
||||
espi->dma_rx = dma_request_channel(mask, ep93xx_spi_dma_filter,
|
||||
&espi->dma_rx_data);
|
||||
if (!espi->dma_rx) {
|
||||
ret = -ENODEV;
|
||||
goto fail_free_page;
|
||||
}
|
||||
|
||||
espi->dma_tx_data.port = EP93XX_DMA_SSP;
|
||||
espi->dma_tx_data.direction = DMA_TO_DEVICE;
|
||||
espi->dma_tx_data.name = "ep93xx-spi-tx";
|
||||
|
||||
espi->dma_tx = dma_request_channel(mask, ep93xx_spi_dma_filter,
|
||||
&espi->dma_tx_data);
|
||||
if (!espi->dma_tx) {
|
||||
ret = -ENODEV;
|
||||
goto fail_release_rx;
|
||||
}
|
||||
|
||||
return 0;
|
||||
|
||||
fail_release_rx:
|
||||
dma_release_channel(espi->dma_rx);
|
||||
espi->dma_rx = NULL;
|
||||
fail_free_page:
|
||||
free_page((unsigned long)espi->zeropage);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void ep93xx_spi_release_dma(struct ep93xx_spi *espi)
|
||||
{
|
||||
if (espi->dma_rx) {
|
||||
dma_release_channel(espi->dma_rx);
|
||||
sg_free_table(&espi->rx_sgt);
|
||||
}
|
||||
if (espi->dma_tx) {
|
||||
dma_release_channel(espi->dma_tx);
|
||||
sg_free_table(&espi->tx_sgt);
|
||||
}
|
||||
|
||||
if (espi->zeropage)
|
||||
free_page((unsigned long)espi->zeropage);
|
||||
}
|
||||
|
||||
static int __init ep93xx_spi_probe(struct platform_device *pdev)
|
||||
{
|
||||
struct spi_master *master;
|
||||
|
|
@ -818,6 +1091,7 @@ static int __init ep93xx_spi_probe(struct platform_device *pdev)
|
|||
goto fail_put_clock;
|
||||
}
|
||||
|
||||
espi->sspdr_phys = res->start + SSPDR;
|
||||
espi->regs_base = ioremap(res->start, resource_size(res));
|
||||
if (!espi->regs_base) {
|
||||
dev_err(&pdev->dev, "failed to map resources\n");
|
||||
|
|
@ -832,10 +1106,13 @@ static int __init ep93xx_spi_probe(struct platform_device *pdev)
|
|||
goto fail_unmap_regs;
|
||||
}
|
||||
|
||||
if (info->use_dma && ep93xx_spi_setup_dma(espi))
|
||||
dev_warn(&pdev->dev, "DMA setup failed. Falling back to PIO\n");
|
||||
|
||||
espi->wq = create_singlethread_workqueue("ep93xx_spid");
|
||||
if (!espi->wq) {
|
||||
dev_err(&pdev->dev, "unable to create workqueue\n");
|
||||
goto fail_free_irq;
|
||||
goto fail_free_dma;
|
||||
}
|
||||
INIT_WORK(&espi->msg_work, ep93xx_spi_work);
|
||||
INIT_LIST_HEAD(&espi->msg_queue);
|
||||
|
|
@ -857,7 +1134,8 @@ static int __init ep93xx_spi_probe(struct platform_device *pdev)
|
|||
|
||||
fail_free_queue:
|
||||
destroy_workqueue(espi->wq);
|
||||
fail_free_irq:
|
||||
fail_free_dma:
|
||||
ep93xx_spi_release_dma(espi);
|
||||
free_irq(espi->irq, espi);
|
||||
fail_unmap_regs:
|
||||
iounmap(espi->regs_base);
|
||||
|
|
@ -901,6 +1179,7 @@ static int __exit ep93xx_spi_remove(struct platform_device *pdev)
|
|||
}
|
||||
spin_unlock_irq(&espi->lock);
|
||||
|
||||
ep93xx_spi_release_dma(espi);
|
||||
free_irq(espi->irq, espi);
|
||||
iounmap(espi->regs_base);
|
||||
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||||
|
|
|
|||
Loading…
Reference in a new issue