Merge series "spi: stm32: various fixes & cleanup" from Alain Volmat <alain.volmat@foss.st.com>:

This series contains fixes & cleanup mainly regarding fifo
and the way end of transfer triggered, when used with or
without DMA.
An additional patch cleans up the pm_runtime calls and another
one enables the autosuspend.

v2: - split pm_runtime fix patch into two
    - correct revert commit subject line

Alain Volmat (6):
  spi: stm32: fixes pm_runtime calls in probe/remove
  spi: stm32: enable pm_runtime autosuspend
  spi: stm32h7: fix full duplex irq handler handling
  spi: stm32: Revert "properly handle 0 byte transfer"
  spi: stm32h7: don't wait for EOT and flush fifo on disable
  spi: stm32: finalize message either on dma callback or EOT

Amelie Delaunay (1):
  spi: stm32h7: rework rx fifo read function

 drivers/spi/spi-stm32.c | 146 +++++++++++++++++-----------------------
 1 file changed, 61 insertions(+), 85 deletions(-)

--
2.25.1

1 files changed, 44 insertions, 78 deletions

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 05618a618939..14ca7ea04e47 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -162,6 +162,8 @@
 #define SPI_3WIRE_TX		3
 #define SPI_3WIRE_RX		4
 
+#define STM32_SPI_AUTOSUSPEND_DELAY		1	/* 1 ms */
+
 /*
  * use PIO for small transfers, avoiding DMA setup/teardown overhead for drivers
  * without fifo buffers.
@@ -568,29 +570,30 @@ static void stm32f4_spi_read_rx(struct stm32_spi *spi)
 /**
  * stm32h7_spi_read_rxfifo - Read bytes in Receive Data Register
  * @spi: pointer to the spi controller data structure
- * @flush: boolean indicating that FIFO should be flushed
  *
  * Write in rx_buf depends on remaining bytes to avoid to write beyond
  * rx_buf end.
  */
-static void stm32h7_spi_read_rxfifo(struct stm32_spi *spi, bool flush)
+static void stm32h7_spi_read_rxfifo(struct stm32_spi *spi)
 {
 	u32 sr = readl_relaxed(spi->base + STM32H7_SPI_SR);
 	u32 rxplvl = FIELD_GET(STM32H7_SPI_SR_RXPLVL, sr);
 
 	while ((spi->rx_len > 0) &&
 	       ((sr & STM32H7_SPI_SR_RXP) ||
-		(flush && ((sr & STM32H7_SPI_SR_RXWNE) || (rxplvl > 0))))) {
+		((sr & STM32H7_SPI_SR_EOT) &&
+		 ((sr & STM32H7_SPI_SR_RXWNE) || (rxplvl > 0))))) {
 		u32 offs = spi->cur_xferlen - spi->rx_len;
 
 		if ((spi->rx_len >= sizeof(u32)) ||
-		    (flush && (sr & STM32H7_SPI_SR_RXWNE))) {
+		    (sr & STM32H7_SPI_SR_RXWNE)) {
 			u32 *rx_buf32 = (u32 *)(spi->rx_buf + offs);
 
 			*rx_buf32 = readl_relaxed(spi->base + STM32H7_SPI_RXDR);
 			spi->rx_len -= sizeof(u32);
 		} else if ((spi->rx_len >= sizeof(u16)) ||
-			   (flush && (rxplvl >= 2 || spi->cur_bpw > 8))) {
+			   (!(sr & STM32H7_SPI_SR_RXWNE) &&
+			    (rxplvl >= 2 || spi->cur_bpw > 8))) {
 			u16 *rx_buf16 = (u16 *)(spi->rx_buf + offs);
 
 			*rx_buf16 = readw_relaxed(spi->base + STM32H7_SPI_RXDR);
@@ -606,8 +609,8 @@ static void stm32h7_spi_read_rxfifo(struct stm32_spi *spi, bool flush)
 		rxplvl = FIELD_GET(STM32H7_SPI_SR_RXPLVL, sr);
 	}
 
-	dev_dbg(spi->dev, "%s%s: %d bytes left\n", __func__,
-		flush ? "(flush)" : "", spi->rx_len);
+	dev_dbg(spi->dev, "%s: %d bytes left (sr=%08x)\n",
+		__func__, spi->rx_len, sr);
 }
 
 /**
@@ -674,18 +677,12 @@ static void stm32f4_spi_disable(struct stm32_spi *spi)
  * stm32h7_spi_disable - Disable SPI controller
  * @spi: pointer to the spi controller data structure
  *
- * RX-Fifo is flushed when SPI controller is disabled. To prevent any data
- * loss, use stm32h7_spi_read_rxfifo(flush) to read the remaining bytes in
- * RX-Fifo.
- * Normally, if TSIZE has been configured, we should relax the hardware at the
- * reception of the EOT interrupt. But in case of error, EOT will not be
- * raised. So the subsystem unprepare_message call allows us to properly
- * complete the transfer from an hardware point of view.
+ * RX-Fifo is flushed when SPI controller is disabled.
  */
 static void stm32h7_spi_disable(struct stm32_spi *spi)
 {
 	unsigned long flags;
-	u32 cr1, sr;
+	u32 cr1;
 
 	dev_dbg(spi->dev, "disable controller\n");
 
@@ -698,25 +695,6 @@ static void stm32h7_spi_disable(struct stm32_spi *spi)
 		return;
 	}
 
-	/* Wait on EOT or suspend the flow */
-	if (readl_relaxed_poll_timeout_atomic(spi->base + STM32H7_SPI_SR,
-					      sr, !(sr & STM32H7_SPI_SR_EOT),
-					      10, 100000) < 0) {
-		if (cr1 & STM32H7_SPI_CR1_CSTART) {
-			writel_relaxed(cr1 | STM32H7_SPI_CR1_CSUSP,
-				       spi->base + STM32H7_SPI_CR1);
-			if (readl_relaxed_poll_timeout_atomic(
-						spi->base + STM32H7_SPI_SR,
-						sr, !(sr & STM32H7_SPI_SR_SUSP),
-						10, 100000) < 0)
-				dev_warn(spi->dev,
-					 "Suspend request timeout\n");
-		}
-	}
-
-	if (!spi->cur_usedma && spi->rx_buf && (spi->rx_len > 0))
-		stm32h7_spi_read_rxfifo(spi, true);
-
 	if (spi->cur_usedma && spi->dma_tx)
 		dmaengine_terminate_all(spi->dma_tx);
 	if (spi->cur_usedma && spi->dma_rx)
@@ -911,7 +889,7 @@ static irqreturn_t stm32h7_spi_irq_thread(int irq, void *dev_id)
 		if (__ratelimit(&rs))
 			dev_dbg_ratelimited(spi->dev, "Communication suspended\n");
 		if (!spi->cur_usedma && (spi->rx_buf && (spi->rx_len > 0)))
-			stm32h7_spi_read_rxfifo(spi, false);
+			stm32h7_spi_read_rxfifo(spi);
 		/*
 		 * If communication is suspended while using DMA, it means
 		 * that something went wrong, so stop the current transfer
@@ -932,8 +910,11 @@ static irqreturn_t stm32h7_spi_irq_thread(int irq, void *dev_id)
 
 	if (sr & STM32H7_SPI_SR_EOT) {
 		if (!spi->cur_usedma && (spi->rx_buf && (spi->rx_len > 0)))
-			stm32h7_spi_read_rxfifo(spi, true);
-		end = true;
+			stm32h7_spi_read_rxfifo(spi);
+		if (!spi->cur_usedma ||
+		    (spi->cur_usedma && (spi->cur_comm == SPI_SIMPLEX_TX ||
+		     spi->cur_comm == SPI_3WIRE_TX)))
+			end = true;
 	}
 
 	if (sr & STM32H7_SPI_SR_TXP)
@@ -942,7 +923,7 @@ static irqreturn_t stm32h7_spi_irq_thread(int irq, void *dev_id)
 
 	if (sr & STM32H7_SPI_SR_RXP)
 		if (!spi->cur_usedma && (spi->rx_buf && (spi->rx_len > 0)))
-			stm32h7_spi_read_rxfifo(spi, false);
+			stm32h7_spi_read_rxfifo(spi);
 
 	writel_relaxed(sr & mask, spi->base + STM32H7_SPI_IFCR);
 
@@ -1041,42 +1022,17 @@ static void stm32f4_spi_dma_tx_cb(void *data)
 }
 
 /**
- * stm32f4_spi_dma_rx_cb - dma callback
+ * stm32_spi_dma_rx_cb - dma callback
  * @data: pointer to the spi controller data structure
  *
  * DMA callback is called when the transfer is complete for DMA RX channel.
  */
-static void stm32f4_spi_dma_rx_cb(void *data)
+static void stm32_spi_dma_rx_cb(void *data)
 {
 	struct stm32_spi *spi = data;
 
 	spi_finalize_current_transfer(spi->master);
-	stm32f4_spi_disable(spi);
-}
-
-/**
- * stm32h7_spi_dma_cb - dma callback
- * @data: pointer to the spi controller data structure
- *
- * DMA callback is called when the transfer is complete or when an error
- * occurs. If the transfer is complete, EOT flag is raised.
- */
-static void stm32h7_spi_dma_cb(void *data)
-{
-	struct stm32_spi *spi = data;
-	unsigned long flags;
-	u32 sr;
-
-	spin_lock_irqsave(&spi->lock, flags);
-
-	sr = readl_relaxed(spi->base + STM32H7_SPI_SR);
-
-	spin_unlock_irqrestore(&spi->lock, flags);
-
-	if (!(sr & STM32H7_SPI_SR_EOT))
-		dev_warn(spi->dev, "DMA error (sr=0x%08x)\n", sr);
-
-	/* Now wait for EOT, or SUSP or OVR in case of error */
+	spi->cfg->disable(spi);
 }
 
 /**
@@ -1242,11 +1198,13 @@ static void stm32f4_spi_transfer_one_dma_start(struct stm32_spi *spi)
  */
 static void stm32h7_spi_transfer_one_dma_start(struct stm32_spi *spi)
 {
-	/* Enable the interrupts relative to the end of transfer */
-	stm32_spi_set_bits(spi, STM32H7_SPI_IER, STM32H7_SPI_IER_EOTIE |
-						 STM32H7_SPI_IER_TXTFIE |
-						 STM32H7_SPI_IER_OVRIE |
-						 STM32H7_SPI_IER_MODFIE);
+	uint32_t ier = STM32H7_SPI_IER_OVRIE | STM32H7_SPI_IER_MODFIE;
+
+	/* Enable the interrupts */
+	if (spi->cur_comm == SPI_SIMPLEX_TX || spi->cur_comm == SPI_3WIRE_TX)
+		ier |= STM32H7_SPI_IER_EOTIE | STM32H7_SPI_IER_TXTFIE;
+
+	stm32_spi_set_bits(spi, STM32H7_SPI_IER, ier);
 
 	stm32_spi_enable(spi);
 
@@ -1645,10 +1603,6 @@ static int stm32_spi_transfer_one(struct spi_master *master,
 	struct stm32_spi *spi = spi_master_get_devdata(master);
 	int ret;
 
-	/* Don't do anything on 0 bytes transfers */
-	if (transfer->len == 0)
-		return 0;
-
 	spi->tx_buf = transfer->tx_buf;
 	spi->rx_buf = transfer->rx_buf;
 	spi->tx_len = spi->tx_buf ? transfer->len : 0;
@@ -1762,7 +1716,7 @@ static const struct stm32_spi_cfg stm32f4_spi_cfg = {
 	.set_mode = stm32f4_spi_set_mode,
 	.transfer_one_dma_start = stm32f4_spi_transfer_one_dma_start,
 	.dma_tx_cb = stm32f4_spi_dma_tx_cb,
-	.dma_rx_cb = stm32f4_spi_dma_rx_cb,
+	.dma_rx_cb = stm32_spi_dma_rx_cb,
 	.transfer_one_irq = stm32f4_spi_transfer_one_irq,
 	.irq_handler_event = stm32f4_spi_irq_event,
 	.irq_handler_thread = stm32f4_spi_irq_thread,
@@ -1782,8 +1736,11 @@ static const struct stm32_spi_cfg stm32h7_spi_cfg = {
 	.set_data_idleness = stm32h7_spi_data_idleness,
 	.set_number_of_data = stm32h7_spi_number_of_data,
 	.transfer_one_dma_start = stm32h7_spi_transfer_one_dma_start,
-	.dma_rx_cb = stm32h7_spi_dma_cb,
-	.dma_tx_cb = stm32h7_spi_dma_cb,
+	.dma_rx_cb = stm32_spi_dma_rx_cb,
+	/*
+	 * dma_tx_cb is not necessary since in case of TX, dma is followed by
+	 * SPI access hence handling is performed within the SPI interrupt
+	 */
 	.transfer_one_irq = stm32h7_spi_transfer_one_irq,
 	.irq_handler_thread = stm32h7_spi_irq_thread,
 	.baud_rate_div_min = STM32H7_SPI_MBR_DIV_MIN,
@@ -1927,6 +1884,9 @@ static int stm32_spi_probe(struct platform_device *pdev)
 	if (spi->dma_tx || spi->dma_rx)
 		master->can_dma = stm32_spi_can_dma;
 
+	pm_runtime_set_autosuspend_delay(&pdev->dev,
+					 STM32_SPI_AUTOSUSPEND_DELAY);
+	pm_runtime_use_autosuspend(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_get_noresume(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
@@ -1938,6 +1898,9 @@ static int stm32_spi_probe(struct platform_device *pdev)
 		goto err_pm_disable;
 	}
 
+	pm_runtime_mark_last_busy(&pdev->dev);
+	pm_runtime_put_autosuspend(&pdev->dev);
+
 	dev_info(&pdev->dev, "driver initialized\n");
 
 	return 0;
@@ -1946,6 +1909,7 @@ err_pm_disable:
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_put_noidle(&pdev->dev);
 	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
 err_dma_release:
 	if (spi->dma_tx)
 		dma_release_channel(spi->dma_tx);
@@ -1970,6 +1934,8 @@ static int stm32_spi_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_put_noidle(&pdev->dev);
 	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
+
 	if (master->dma_tx)
 		dma_release_channel(master->dma_tx);
 	if (master->dma_rx)