Message-Id: <E1dfUHz-0005TP-1f@debutante>
Date:   Wed, 09 Aug 2017 17:56:59 +0100
From:   Mark Brown <broonie@...nel.org>
To:     H Hartley Sweeten <hsweeten@...ionengravers.com>
Cc:     Chris Packham <chris.packham@...iedtelesis.co.nz>,
        Mark Brown <broonie@...nel.org>, broonie@...nel.org,
        linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org,
        andy.shevchenko@...il.com, hsweeten@...ionengravers.com,
        linux-spi@...r.kernel.org
Subject: Applied "spi: spi-ep93xx: use the default master transfer queueing mechanism" to the spi tree

The patch

   spi: spi-ep93xx: use the default master transfer queueing mechanism

has been applied to the spi tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From d9a017713d909697f528a3f6569d5deb7477cea1 Mon Sep 17 00:00:00 2001
From: H Hartley Sweeten <hsweeten@...ionengravers.com>
Date: Wed, 9 Aug 2017 08:51:31 +1200
Subject: [PATCH] spi: spi-ep93xx: use the default master transfer queueing
 mechanism

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

Signed-off-by: H Hartley Sweeten <hsweeten@...ionengravers.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
Signed-off-by: Chris Packham <chris.packham@...iedtelesis.co.nz>
Signed-off-by: Mark Brown <broonie@...nel.org>
---
 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

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