[PATCH] spi: spi-ep93xx: use the default master transfer queueing mechanism

From: H Hartley Sweeten
Date: Tue Aug 08 2017 - 16:51:31 EST

Update this driver to the default implementation of transfer_one_message().

Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
drivers/spi/spi-ep93xx.c | 322 ++++++++++++++++-------------------------------
1 file changed, 108 insertions(+), 214 deletions(-)

diff --git a/drivers/spi/spi-ep93xx.c b/drivers/spi/spi-ep93xx.c
index cf7d8175bf79..e5cc07357746 100644
--- a/drivers/spi/spi-ep93xx.c
+++ b/drivers/spi/spi-ep93xx.c
@@ -73,7 +73,6 @@
* @clk: clock for the controller
* @mmio: pointer to ioremap()'d registers
* @sspdr_phys: physical address of the SSPDR register
- * @wait: wait here until given transfer is completed
* @tx: current byte in transfer to transmit
* @rx: current byte in transfer to receive
* @fifo_level: how full is FIFO (%0..%SPI_FIFO_SIZE - %1). Receiving one
@@ -91,7 +90,6 @@ struct ep93xx_spi {
struct clk *clk;
void __iomem *mmio;
unsigned long sspdr_phys;
- struct completion wait;
size_t tx;
size_t rx;
size_t fifo_level;
@@ -123,8 +121,7 @@ static int ep93xx_spi_calc_divisors(struct spi_master *master,

/*
* Make sure that max value is between values supported by the
- * controller. Note that minimum value is already checked in
- * ep93xx_spi_transfer_one_message().
+ * controller.
*/
rate = clamp(rate, master->min_speed_hz, master->max_speed_hz);

@@ -149,15 +146,6 @@ static int ep93xx_spi_calc_divisors(struct spi_master *master,
return -EINVAL;
}

-static void ep93xx_spi_cs_control(struct spi_device *spi, bool enable)
-{
- if (spi->mode & SPI_CS_HIGH)
- enable = !enable;
-
- if (gpio_is_valid(spi->cs_gpio))
- gpio_set_value(spi->cs_gpio, !enable);
-}
-
static int ep93xx_spi_chip_setup(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *xfer)
@@ -188,34 +176,38 @@ static int ep93xx_spi_chip_setup(struct spi_master *master,
return 0;
}

-static void ep93xx_do_write(struct ep93xx_spi *espi, struct spi_transfer *t)
+static void ep93xx_do_write(struct spi_master *master)
{
+ struct ep93xx_spi *espi = spi_master_get_devdata(master);
+ struct spi_transfer *xfer = master->cur_msg->state;
u32 val = 0;

- if (t->bits_per_word > 8) {
- if (t->tx_buf)
- val = ((u16 *)t->tx_buf)[espi->tx];
+ if (xfer->bits_per_word > 8) {
+ if (xfer->tx_buf)
+ val = ((u16 *)xfer->tx_buf)[espi->tx];
espi->tx += 2;
} else {
- if (t->tx_buf)
- val = ((u8 *)t->tx_buf)[espi->tx];
+ if (xfer->tx_buf)
+ val = ((u8 *)xfer->tx_buf)[espi->tx];
espi->tx += 1;
}
writel(val, espi->mmio + SSPDR);
}

-static void ep93xx_do_read(struct ep93xx_spi *espi, struct spi_transfer *t)
+static void ep93xx_do_read(struct spi_master *master)
{
+ struct ep93xx_spi *espi = spi_master_get_devdata(master);
+ struct spi_transfer *xfer = master->cur_msg->state;
u32 val;

val = readl(espi->mmio + SSPDR);
- if (t->bits_per_word > 8) {
- if (t->rx_buf)
- ((u16 *)t->rx_buf)[espi->rx] = val;
+ if (xfer->bits_per_word > 8) {
+ if (xfer->rx_buf)
+ ((u16 *)xfer->rx_buf)[espi->rx] = val;
espi->rx += 2;
} else {
- if (t->rx_buf)
- ((u8 *)t->rx_buf)[espi->rx] = val;
+ if (xfer->rx_buf)
+ ((u8 *)xfer->rx_buf)[espi->rx] = val;
espi->rx += 1;
}
}
@@ -234,45 +226,26 @@ static void ep93xx_do_read(struct ep93xx_spi *espi, struct spi_transfer *t)
static int ep93xx_spi_read_write(struct spi_master *master)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
- struct spi_transfer *t = master->cur_msg->state;
+ struct spi_transfer *xfer = master->cur_msg->state;

/* read as long as RX FIFO has frames in it */
while ((readl(espi->mmio + SSPSR) & SSPSR_RNE)) {
- ep93xx_do_read(espi, t);
+ ep93xx_do_read(master);
espi->fifo_level--;
}

/* write as long as TX FIFO has room */
- while (espi->fifo_level < SPI_FIFO_SIZE && espi->tx < t->len) {
- ep93xx_do_write(espi, t);
+ while (espi->fifo_level < SPI_FIFO_SIZE && espi->tx < xfer->len) {
+ ep93xx_do_write(master);
espi->fifo_level++;
}

- if (espi->rx == t->len)
+ if (espi->rx == xfer->len)
return 0;

return -EINPROGRESS;
}

-static void ep93xx_spi_pio_transfer(struct spi_master *master)
-{
- struct ep93xx_spi *espi = spi_master_get_devdata(master);
-
- /*
- * 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(master)) {
- u32 val;
-
- val = readl(espi->mmio + SSPCR1);
- val |= (SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE);
- writel(val, espi->mmio + SSPCR1);
-
- wait_for_completion(&espi->wait);
- }
-}
-
/**
* ep93xx_spi_dma_prepare() - prepares a DMA transfer
* @master: SPI master
@@ -287,7 +260,7 @@ ep93xx_spi_dma_prepare(struct spi_master *master,
enum dma_transfer_direction dir)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
- struct spi_transfer *t = master->cur_msg->state;
+ struct spi_transfer *xfer = master->cur_msg->state;
struct dma_async_tx_descriptor *txd;
enum dma_slave_buswidth buswidth;
struct dma_slave_config conf;
@@ -295,10 +268,10 @@ ep93xx_spi_dma_prepare(struct spi_master *master,
struct sg_table *sgt;
struct dma_chan *chan;
const void *buf, *pbuf;
- size_t len = t->len;
+ size_t len = xfer->len;
int i, ret, nents;

- if (t->bits_per_word > 8)
+ if (xfer->bits_per_word > 8)
buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
else
buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
@@ -308,14 +281,14 @@ ep93xx_spi_dma_prepare(struct spi_master *master,

if (dir == DMA_DEV_TO_MEM) {
chan = espi->dma_rx;
- buf = t->rx_buf;
+ buf = xfer->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;
+ buf = xfer->tx_buf;
sgt = &espi->tx_sgt;

conf.dst_addr = espi->sspdr_phys;
@@ -406,10 +379,15 @@ static void ep93xx_spi_dma_finish(struct spi_master *master,

static void ep93xx_spi_dma_callback(void *callback_param)
{
- complete(callback_param);
+ struct spi_master *master = callback_param;
+
+ ep93xx_spi_dma_finish(master, DMA_MEM_TO_DEV);
+ ep93xx_spi_dma_finish(master, DMA_DEV_TO_MEM);
+
+ spi_finalize_current_transfer(master);
}

-static void ep93xx_spi_dma_transfer(struct spi_master *master)
+static int ep93xx_spi_dma_transfer(struct spi_master *master)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
struct dma_async_tx_descriptor *rxd, *txd;
@@ -417,177 +395,29 @@ static void ep93xx_spi_dma_transfer(struct spi_master *master)
rxd = ep93xx_spi_dma_prepare(master, DMA_DEV_TO_MEM);
if (IS_ERR(rxd)) {
dev_err(&master->dev, "DMA RX failed: %ld\n", PTR_ERR(rxd));
- master->cur_msg->status = PTR_ERR(rxd);
- return;
+ return PTR_ERR(rxd);
}

txd = ep93xx_spi_dma_prepare(master, DMA_MEM_TO_DEV);
if (IS_ERR(txd)) {
ep93xx_spi_dma_finish(master, DMA_DEV_TO_MEM);
dev_err(&master->dev, "DMA TX failed: %ld\n", PTR_ERR(txd));
- master->cur_msg->status = PTR_ERR(txd);
- return;
+ return PTR_ERR(txd);
}

/* We are ready when RX is done */
rxd->callback = ep93xx_spi_dma_callback;
- rxd->callback_param = &espi->wait;
+ rxd->callback_param = master;

- /* Now submit both descriptors and wait while they finish */
+ /* Now submit both descriptors and start DMA */
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(master, DMA_MEM_TO_DEV);
- ep93xx_spi_dma_finish(master, DMA_DEV_TO_MEM);
-}
-
-/**
- * ep93xx_spi_process_transfer() - processes one SPI transfer
- * @master: SPI master
- * @msg: current message
- * @t: transfer to process
- *
- * This function processes one SPI transfer given in @t. Function waits until
- * transfer is complete (may sleep) and updates @msg->status based on whether
- * transfer was successfully processed or not.
- */
-static void ep93xx_spi_process_transfer(struct spi_master *master,
- struct spi_message *msg,
- struct spi_transfer *t)
-{
- struct ep93xx_spi *espi = spi_master_get_devdata(master);
- int err;
-
- msg->state = t;
-
- err = ep93xx_spi_chip_setup(master, msg->spi, t);
- if (err) {
- dev_err(&master->dev,
- "failed to setup chip for transfer\n");
- msg->status = err;
- return;
- }
-
- espi->rx = 0;
- espi->tx = 0;
-
- /*
- * 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 (espi->dma_rx && t->len > SPI_FIFO_SIZE)
- ep93xx_spi_dma_transfer(master);
- else
- ep93xx_spi_pio_transfer(master);
-
- /*
- * In case of error during transmit, we bail out from processing
- * the message.
- */
- 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.
- */
- if (t->delay_usecs) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- schedule_timeout(usecs_to_jiffies(t->delay_usecs));
- }
- if (t->cs_change) {
- if (!list_is_last(&t->transfer_list, &msg->transfers)) {
- /*
- * In case protocol driver is asking us to drop the
- * chipselect briefly, we let the scheduler to handle
- * any "delay" here.
- */
- ep93xx_spi_cs_control(msg->spi, false);
- cond_resched();
- ep93xx_spi_cs_control(msg->spi, true);
- }
- }
-}
-
-/*
- * ep93xx_spi_process_message() - process one SPI message
- * @master: SPI master
- * @msg: message to process
- *
- * This function processes a single SPI message. We go through all transfers in
- * the message and pass them to ep93xx_spi_process_transfer(). Chipselect is
- * asserted during the whole message (unless per transfer cs_change is set).
- *
- * @msg->status contains %0 in case of success or negative error code in case of
- * failure.
- */
-static void ep93xx_spi_process_message(struct spi_master *master,
- struct spi_message *msg)
-{
- struct ep93xx_spi *espi = spi_master_get_devdata(master);
- unsigned long timeout;
- struct spi_transfer *t;
-
- /*
- * Just to be sure: flush any data from RX FIFO.
- */
- timeout = jiffies + msecs_to_jiffies(SPI_TIMEOUT);
- while (readl(espi->mmio + SSPSR) & SSPSR_RNE) {
- if (time_after(jiffies, timeout)) {
- dev_warn(&master->dev,
- "timeout while flushing RX FIFO\n");
- msg->status = -ETIMEDOUT;
- return;
- }
- readl(espi->mmio + SSPDR);
- }
-
- /*
- * We explicitly handle FIFO level. This way we don't have to check TX
- * FIFO status using %SSPSR_TNF bit which may cause RX FIFO overruns.
- */
- espi->fifo_level = 0;
-
- /*
- * Assert the chipselect.
- */
- ep93xx_spi_cs_control(msg->spi, true);
-
- list_for_each_entry(t, &msg->transfers, transfer_list) {
- ep93xx_spi_process_transfer(master, msg, t);
- if (msg->status)
- break;
- }
-
- /*
- * Now the whole message is transferred (or failed for some reason). We
- * deselect the device and disable the SPI controller.
- */
- ep93xx_spi_cs_control(msg->spi, false);
-}
-
-static int ep93xx_spi_transfer_one_message(struct spi_master *master,
- struct spi_message *msg)
-{
- struct ep93xx_spi *espi = spi_master_get_devdata(master);
-
- msg->state = NULL;
- msg->status = 0;
- msg->actual_length = 0;
-
- ep93xx_spi_process_message(master, msg);
-
- spi_finalize_current_message(master);
-
- return 0;
+ /* signal that we need to wait for completion */
+ return 1;
}

static irqreturn_t ep93xx_spi_interrupt(int irq, void *dev_id)
@@ -630,11 +460,76 @@ static irqreturn_t ep93xx_spi_interrupt(int irq, void *dev_id)
val &= ~(SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE);
writel(val, espi->mmio + SSPCR1);

- complete(&espi->wait);
+ spi_finalize_current_transfer(master);

return IRQ_HANDLED;
}

+static int ep93xx_spi_transfer_one(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *xfer)
+{
+ struct ep93xx_spi *espi = spi_master_get_devdata(master);
+ u32 val;
+ int ret;
+
+ ret = ep93xx_spi_chip_setup(master, spi, xfer);
+ if (ret) {
+ dev_err(&master->dev, "failed to setup chip for transfer\n");
+ return ret;
+ }
+
+ master->cur_msg->state = xfer;
+ espi->rx = 0;
+ espi->tx = 0;
+
+ /*
+ * 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 (espi->dma_rx && xfer->len > SPI_FIFO_SIZE)
+ return ep93xx_spi_dma_transfer(master);
+
+ /* Using PIO so prime the TX FIFO and enable interrupts */
+ ep93xx_spi_read_write(master);
+
+ val = readl(espi->mmio + SSPCR1);
+ val |= (SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE);
+ writel(val, espi->mmio + SSPCR1);
+
+ /* signal that we need to wait for completion */
+ return 1;
+}
+
+static int ep93xx_spi_prepare_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct ep93xx_spi *espi = spi_master_get_devdata(master);
+ unsigned long timeout;
+
+ /*
+ * Just to be sure: flush any data from RX FIFO.
+ */
+ timeout = jiffies + msecs_to_jiffies(SPI_TIMEOUT);
+ while (readl(espi->mmio + SSPSR) & SSPSR_RNE) {
+ if (time_after(jiffies, timeout)) {
+ dev_warn(&master->dev,
+ "timeout while flushing RX FIFO\n");
+ return -ETIMEDOUT;
+ }
+ readl(espi->mmio + SSPDR);
+ }
+
+ /*
+ * We explicitly handle FIFO level. This way we don't have to check TX
+ * FIFO status using %SSPSR_TNF bit which may cause RX FIFO overruns.
+ */
+ espi->fifo_level = 0;
+
+ return 0;
+}
+
static int ep93xx_spi_prepare_hardware(struct spi_master *master)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
@@ -769,7 +664,8 @@ static int ep93xx_spi_probe(struct platform_device *pdev)

master->prepare_transfer_hardware = ep93xx_spi_prepare_hardware;
master->unprepare_transfer_hardware = ep93xx_spi_unprepare_hardware;
- master->transfer_one_message = ep93xx_spi_transfer_one_message;
+ master->prepare_message = ep93xx_spi_prepare_message;
+ master->transfer_one = ep93xx_spi_transfer_one;
master->bus_num = pdev->id;
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
@@ -810,8 +706,6 @@ static int ep93xx_spi_probe(struct platform_device *pdev)
goto fail_release_master;
}

- init_completion(&espi->wait);
-
/*
* Calculate maximum and minimum supported clock rates
* for the controller.
--
2.13.3